CONTENTS

• NAME
• DESCRIPTION
• AV Handling
• Callback Functions
• Casting
• Character case changing
• Character classification
• Compiler and Preprocessor information
• Compiler directives
• Compile-time scope hooks
• Concurrency
• COPs and Hint Hashes
• Custom Operators
• CV Handling
• Debugging
• Display functions
• Embedding, Threads, and Interpreter Cloning
• Errno
• Exception Handling (simple) Macros
• Filesystem configuration values
• Floating point
• General Configuration
  • List of capability HAS_foo symbols
  • List of #include needed symbols
• Global Variables
• GV Handling and Stashes
• Hook manipulation
• HV Handling
• Input/Output
• Integer
• I/O Formats
• Lexer interface
• Locales
• Magic
• Memory Management
• MRO
• Multicall Functions
• Numeric Functions
• Optrees
• Pack and Unpack
• Pad Data Structures
• Password and Group access
• Paths to system commands
• Prototype information
• Reference-counted stack manipulation
• REGEXP Functions
• Reports and Formats
• Signals
• Site configuration
• Sockets configuration values
• Source Filters
• Stack Manipulation Macros
• String Handling
• SV Flags
• SV Handling
• Tainting
• Time
• Typedef names
• Unicode Support
• Utility Functions
• Versioning
• Warning and Dieing
• XS
• Undocumented elements
• AUTHORS
• SEE ALSO

#NAME

perlapi - autogenerated documentation for the perl public API

#DESCRIPTION

This file contains most of the documentation of the perl public API, as generated by embed.pl. Specifically, it is a listing of functions, macros, flags, and variables that may be used by extension writers. Besides perlintern and config.h, some items are listed here as being actually documented in another pod.

At the end is a list of functions which have yet to be documented. Patches welcome! The interfaces of these are subject to change without notice.

Some of the functions documented here are consolidated so that a single entry serves for multiple functions which all do basically the same thing, but have some slight differences. For example, one form might process magic, while another doesn't. The name of each variation is listed at the top of the single entry.

The names of all API functions begin with the prefix Perl_ so as to prevent any name collisions with your code. But, unless -Accflags=-DPERL_NO_SHORT_NAMES has been specified in compiling your code (see "Hiding Perl_" in perlembed), synonymous macros are also available to you that don't have this prefix, and also hide from you the need (or not) to have a thread context parameter passed to the function. Generally, code is easier to write and to read when the short form is used, so in practice that compilation flag is not used. Not all functions have the short form; both are listed here when available.

Anything not listed here or in the other mentioned pods is not part of the public API, and should not be used by extension writers at all. For these reasons, blindly using functions listed in proto.h is to be avoided when writing extensions.

In Perl, unlike C, a string of characters may generally contain embedded NUL characters. Sometimes in the documentation a Perl string is referred to as a "buffer" to distinguish it from a C string, but sometimes they are both just referred to as strings.

Note that all Perl API global variables must be referenced with the PL_ prefix. Again, those not listed here are not to be used by extension writers, and may be changed or removed without notice; same with macros. Some macros are provided for compatibility with the older, unadorned names, but this support may be disabled in a future release.

Perl was originally written to handle US-ASCII only (that is characters whose ordinal numbers are in the range 0 - 127). And documentation and comments may still use the term ASCII, when sometimes in fact the entire range from 0 - 255 is meant.

The non-ASCII characters below 256 can have various meanings, depending on various things. (See, most notably, perllocale.) But usually the whole range can be referred to as ISO-8859-1. Often, the term "Latin-1" (or "Latin1") is used as an equivalent for ISO-8859-1. But some people treat "Latin1" as referring just to the characters in the range 128 through 255, or sometimes from 160 through 255. This documentation uses "Latin1" and "Latin-1" to refer to all 256 characters.

Note that Perl can be compiled and run under either ASCII or EBCDIC (See perlebcdic). Most of the documentation (and even comments in the code) ignore the EBCDIC possibility. For almost all purposes the differences are transparent. As an example, under EBCDIC, instead of UTF-8, UTF-EBCDIC is used to encode Unicode strings, and so whenever this documentation refers to utf8 (and variants of that name, including in function names), it also (essentially transparently) means UTF-EBCDIC. But the ordinals of characters differ between ASCII, EBCDIC, and the UTF- encodings, and a string encoded in UTF-EBCDIC may occupy a different number of bytes than in UTF-8.

The organization of this document is tentative and subject to change. Suggestions and patches welcome perl5-porters@perl.org.

The API elements are grouped by functionality into sections, as follows. Within sections the elements are ordered alphabetically, ignoring case, with non-leading underscores sorted first, and leading underscores and digits sorted last.

#"AV Handling"

#"Callback Functions"

#"Casting"

#"Character case changing"

#"Character classification"

#"Compiler and Preprocessor information"

#"Compiler directives"

#"Compile-time scope hooks"

#"Concurrency"

#"COPs and Hint Hashes"

#"Custom Operators"

#"CV Handling"

#"Debugging"

#"Display functions"

#"Embedding, Threads, and Interpreter Cloning"

#"Errno"

#"Exception Handling (simple) Macros"

#"Filesystem configuration values"

#"Floating point"

#"General Configuration"

#"Global Variables"

#"GV Handling and Stashes"

#"Hook manipulation"

#"HV Handling"

#"Input/Output"

#"Integer"

#"I/O Formats"

#"Lexer interface"

#"Locales"

#"Magic"

#"Memory Management"

#"MRO"

#"Multicall Functions"

#"Numeric Functions"

#"Optrees"

#"Pack and Unpack"

#"Pad Data Structures"

#"Password and Group access"

#"Paths to system commands"

#"Prototype information"

#"Reference-counted stack manipulation"

#"REGEXP Functions"

#"Reports and Formats"

#"Signals"

#"Site configuration"

#"Sockets configuration values"

#"Source Filters"

#"Stack Manipulation Macros"

#"String Handling"

#"SV Flags"

#"SV Handling"

#"Tainting"

#"Time"

#"Typedef names"

#"Unicode Support"

#"Utility Functions"

#"Versioning"

#"Warning and Dieing"

#"XS"

#"Undocumented elements"

The listing below is alphabetical, case insensitive.

#AV Handling

#AV

Described in perlguts.

#av_clear

Frees all the elements of an array, leaving it empty. The XS equivalent of @array = (). See also "av_undef".

Note that it is possible that the actions of a destructor called directly or indirectly by freeing an element of the array could cause the reference count of the array itself to be reduced (e.g. by deleting an entry in the symbol table). So it is a possibility that the AV could have been freed (or even reallocated) on return from the call unless you hold a reference to it.

void       av_clear(      AV *av)
void  Perl_av_clear(pTHX_ AV *av)

#av_count

Returns the number of elements in the array av. This is the true length of the array, including any undefined elements. It is always the same as av_top_index(av) + 1.

Size_t       av_count(      AV *av)
Size_t  Perl_av_count(pTHX_ AV *av)

#av_create_and_push

Push an SV onto the end of the array, creating the array if necessary. A small internal helper function to remove a commonly duplicated idiom.

void  Perl_av_create_and_push(pTHX_ AV ** const avp,
                                    SV * const val)

#av_create_and_unshift_one

Unshifts an SV onto the beginning of the array, creating the array if necessary. A small internal helper function to remove a commonly duplicated idiom.

SV **  Perl_av_create_and_unshift_one(pTHX_ AV ** const avp,
                                            SV * const val)

#av_delete

Deletes the element indexed by key from the array, makes the element mortal, and returns it. If flags equals G_DISCARD, the element is freed and NULL is returned. NULL is also returned if key is out of range.

Perl equivalent: splice(@myarray, $key, 1, undef) (with the splice in void context if G_DISCARD is present).

SV *       av_delete(      AV *av, SSize_t key, I32 flags)
SV *  Perl_av_delete(pTHX_ AV *av, SSize_t key, I32 flags)

#av_exists

Returns true if the element indexed by key has been initialized.

This relies on the fact that uninitialized array elements are set to NULL.

Perl equivalent: exists($myarray[$key]).

bool       av_exists(      AV *av, SSize_t key)
bool  Perl_av_exists(pTHX_ AV *av, SSize_t key)

#av_extend

Pre-extend an array so that it is capable of storing values at indexes 0..key. Thus av_extend(av,99) guarantees that the array can store 100 elements, i.e. that av_store(av, 0, sv) through av_store(av, 99, sv) on a plain array will work without any further memory allocation.

If the av argument is a tied array then will call the EXTEND tied array method with an argument of (key+1).

void       av_extend(      AV *av, SSize_t key)
void  Perl_av_extend(pTHX_ AV *av, SSize_t key)

#av_fetch

Returns the SV at the specified index in the array. The key is the index. If lval is true, you are guaranteed to get a real SV back (in case it wasn't real before), which you can then modify. Check that the return value is non-NULL before dereferencing it to a SV*.

See "Understanding the Magic of Tied Hashes and Arrays" in perlguts for more information on how to use this function on tied arrays.

The rough perl equivalent is $myarray[$key].

SV **       av_fetch(      AV *av, SSize_t key, I32 lval)
SV **  Perl_av_fetch(pTHX_ AV *av, SSize_t key, I32 lval)

#av_fill

Set the highest index in the array to the given number, equivalent to Perl's $#array = $fill;.

The number of elements in the array will be fill + 1 after av_fill() returns. If the array was previously shorter, then the additional elements appended are set to NULL. If the array was longer, then the excess elements are freed. av_fill(av, -1) is the same as av_clear(av).

void       av_fill(      AV *av, SSize_t fill)
void  Perl_av_fill(pTHX_ AV *av, SSize_t fill)

#av_len*

Described under "av_top_index"

#av_make

Creates a new AV and populates it with a list (**strp, length size) of SVs. A copy is made of each SV, so their refcounts are not changed. The new AV will have a reference count of 1.

Perl equivalent: my @new_array = ($scalar1, $scalar2, $scalar3...);

AV *       av_make(      SSize_t size, SV **strp)
AV *  Perl_av_make(pTHX_ SSize_t size, SV **strp)

#av_pop

Removes one SV from the end of the array, reducing its size by one and returning the SV (transferring control of one reference count) to the caller. Returns &PL_sv_undef if the array is empty.

Perl equivalent: pop(@myarray);

SV *       av_pop(      AV *av)
SV *  Perl_av_pop(pTHX_ AV *av)

#av_push

#av_push_simple

These each push an SV (transferring control of one reference count) onto the end of the array. The array will grow automatically to accommodate the addition.

Perl equivalent: push @myarray, $val;.

av_push is the general purpose form, suitable for all situations.

av_push_simple is a cut-down version of av_push that assumes that the array is very straightforward, with no magic, not readonly, and is AvREAL (see "Real AVs - and those that are not" in perlguts), and that key is not less than -1. This function MUST NOT be used in situations where any of those assumptions may not hold.

void       av_push       (      AV *av, SV *val)
void  Perl_av_push       (pTHX_ AV *av, SV *val)
void       av_push_simple(      AV *av, SV *val)
void  Perl_av_push_simple(pTHX_ AV *av, SV *val)

#av_shift

Removes one SV from the start of the array, reducing its size by one and returning the SV (transferring control of one reference count) to the caller. Returns &PL_sv_undef if the array is empty.

Perl equivalent: shift(@myarray);

SV *       av_shift(      AV *av)
SV *  Perl_av_shift(pTHX_ AV *av)

#av_store

Stores an SV in an array. The array index is specified as key. The return value will be NULL if the operation failed or if the value did not need to be actually stored within the array (as in the case of tied arrays). Otherwise, it can be dereferenced to get the SV* that was stored there (= val)).

Note that the caller is responsible for suitably incrementing the reference count of val before the call, and decrementing it if the function returned NULL.

Approximate Perl equivalent: splice(@myarray, $key, 1, $val).

See "Understanding the Magic of Tied Hashes and Arrays" in perlguts for more information on how to use this function on tied arrays.

SV **       av_store(      AV *av, SSize_t key, SV *val)
SV **  Perl_av_store(pTHX_ AV *av, SSize_t key, SV *val)

#av_top_index

#av_tindex

#AvFILL

#av_len

These behave identically. If the array av is empty, these return -1; otherwise they return the maximum value of the indices of all the array elements which are currently defined in av.

They process 'get' magic.

The Perl equivalent for these is $#av.

Note that, unlike what the name av_len implies, it returns the maximum index in the array. This is unlike "sv_len", which returns what you would expect. To get the actual number of elements in an array, use "av_count".

SSize_t       av_top_index(      AV *av)
SSize_t       av_tindex   (      AV *av)
SSize_t       AvFILL      (      AV* av)
SSize_t       av_len      (      AV *av)
SSize_t  Perl_av_len      (pTHX_ AV *av)

#av_undef

Undefines the array. The XS equivalent of undef(@array).

As well as freeing all the elements of the array (like av_clear()), this also frees the memory used by the av to store its list of scalars.

See "av_clear" for a note about the array possibly being invalid on return.

void       av_undef(      AV *av)
void  Perl_av_undef(pTHX_ AV *av)

#av_unshift

Unshift the given number of undef values onto the beginning of the array. The array will grow automatically to accommodate the addition.

Perl equivalent: unshift @myarray, ((undef) x $num);

void       av_unshift(      AV *av, SSize_t num)
void  Perl_av_unshift(pTHX_ AV *av, SSize_t num)

#AvALLOC

Described in perlguts.

AvALLOC(AV* av)

#AvARRAY

Returns a pointer to the AV's internal SV* array.

This is useful for doing pointer arithmetic on the array. If all you need is to look up an array element, then prefer av_fetch.

SV**  AvARRAY(AV* av)

#AvFILL*

Described under "av_top_index"

#AvREFCNT_inc

#AvREFCNT_inc_simple

#AvREFCNT_inc_simple_NN

These all increment the reference count of the given SV, which must be an AV. They are useful when assigning the result into a typed pointer as they avoid the need to cast the result to the appropriate type.

AV *  AvREFCNT_inc          (AV *av)
AV *  AvREFCNT_inc_simple   (AV *av)
AV *  AvREFCNT_inc_simple_NN(AV *av)

#get_av

Returns the AV of the specified Perl global or package array with the given name (so it won't work on lexical variables). flags are passed to gv_fetchpv. If GV_ADD is set and the Perl variable does not exist then it will be created. If flags is zero (ignoring SVf_UTF8) and the variable does not exist then NULL is returned.

Perl equivalent: @{"$name"}.

NOTE: the perl_get_av() form is deprecated.

AV *       get_av(      const char *name, I32 flags)
AV *  Perl_get_av(pTHX_ const char *name, I32 flags)

#newAV

#newAV_mortal

#newAV_alloc_x

#newAV_alloc_xz

These all create a new AV, setting the reference count to 1. If you also know the initial elements of the array with, see "av_make".

As background, an array consists of three things:

1. A data structure containing information about the array as a whole, such as its size and reference count.

2. A C language array of pointers to the individual elements. These are treated as pointers to SVs, so all must be castable to SV*.

3. The individual elements themselves. These could be, for instance, SVs and/or AVs and/or HVs, etc.

An empty array need only have the first data structure, and all these functions create that. They differ in what else they do, as follows:

#newAV form

This does nothing beyond creating the whole-array data structure. The Perl equivalent is approximately my @array;

This is useful when the minimum size of the array could be zero (perhaps there are likely code paths that will entirely skip using it).

If the array does get used, the pointers data structure will need to be allocated at that time. This will end up being done by "av_extend">, either explicitly:

av_extend(av, len);

or implicitly when the first element is stored:

(void)av_store(av, 0, sv);

Unused array elements are typically initialized by av_extend.

#newAV_mortal form

This also creates the whole-array data structure, but also mortalises it. (That is to say, a reference to the AV is added to the temps stack.)

#newAV_alloc_x form

This effectively does a newAV followed by also allocating (uninitialized) space for the pointers array. This is used when you know ahead of time the likely minimum size of the array. It is more efficient to do this than doing a plain newAV followed by an av_extend.

Of course the array can be extended later should it become necessary.

size must be at least 1.

#newAV_alloc_xz form

This is newAV_alloc_x, but initializes each pointer in it to NULL. This gives added safety to guard against them being read before being set.

size must be at least 1.

The following examples all result in an array that can fit four elements (indexes 0 .. 3):

AV *av = newAV();
av_extend(av, 3);
AV *av = newAV_alloc_x(4);
AV *av = newAV_alloc_xz(4);

In contrast, the following examples allocate an array that is only guaranteed to fit one element without extending:

AV *av = newAV_alloc_x(1);
AV *av = newAV_alloc_xz(1);

AV *       newAV         ()
AV *  Perl_newAV         (pTHX)
AV *       newAV_mortal  ()
AV *       newAV_alloc_x (SSize_t size)
AV *       newAV_alloc_xz(SSize_t size)

#newAVav

Creates a new AV and populates it with values copied from an existing AV. The new AV will have a reference count of 1, and will contain newly created SVs copied from the original SV. The original source will remain unchanged.

Perl equivalent: my @new_array = @existing_array;

AV *       newAVav(      AV *oav)
AV *  Perl_newAVav(pTHX_ AV *oav)

#newAVhv

Creates a new AV and populates it with keys and values copied from an existing HV. The new AV will have a reference count of 1, and will contain newly created SVs copied from the original HV. The original source will remain unchanged.

Perl equivalent: my @new_array = %existing_hash;

AV *       newAVhv(      HV *ohv)
AV *  Perl_newAVhv(pTHX_ HV *ohv)

#Nullav

DEPRECATED! It is planned to remove Nullav from a future release of Perl. Do not use it for new code; remove it from existing code.

Null AV pointer.

(deprecated - use (AV *)NULL instead)

#Callback Functions

#call_argv

Performs a callback to the specified named and package-scoped Perl subroutine with argv (a NULL-terminated array of strings) as arguments. See perlcall.

Approximate Perl equivalent: &{"$sub_name"}(@$argv).

NOTE: the perl_call_argv() form is deprecated.

SSize_t       call_argv(      const char *sub_name, I32 flags,
                              char **argv)
SSize_t  Perl_call_argv(pTHX_ const char *sub_name, I32 flags,
                              char **argv)

#call_method

Performs a callback to the specified Perl method. The blessed object must be on the stack. See perlcall.

NOTE: the perl_call_method() form is deprecated.

SSize_t       call_method(      const char *methname, I32 flags)
SSize_t  Perl_call_method(pTHX_ const char *methname, I32 flags)

#call_pv

Performs a callback to the specified Perl sub. See perlcall.

NOTE: the perl_call_pv() form is deprecated.

SSize_t       call_pv(      const char *sub_name, I32 flags)
SSize_t  Perl_call_pv(pTHX_ const char *sub_name, I32 flags)

#call_sv

Performs a callback to the Perl sub specified by the SV.

If neither the G_METHOD nor G_METHOD_NAMED flag is supplied, the SV may be any of a CV, a GV, a reference to a CV, a reference to a GV or SvPV(sv) will be used as the name of the sub to call.

If the G_METHOD flag is supplied, the SV may be a reference to a CV or SvPV(sv) will be used as the name of the method to call.

If the G_METHOD_NAMED flag is supplied, SvPV(sv) will be used as the name of the method to call.

Some other values are treated specially for internal use and should not be depended on.

See perlcall.

NOTE: the perl_call_sv() form is deprecated.

SSize_t       call_sv(      SV *sv, I32 flags)
SSize_t  Perl_call_sv(pTHX_ SV *sv, I32 flags)

#DESTRUCTORFUNC_NOCONTEXT_t

#DESTRUCTORFUNC_t

Described in perlguts.

#ENTER

Opening bracket on a callback. See "LEAVE" and perlcall.

ENTER;

#ENTER_with_name

Same as "ENTER", but when debugging is enabled it also associates the given literal string with the new scope.

ENTER_with_name("name");

#eval_pv

Tells Perl to eval the given string in scalar context and return an SV* result.

NOTE: the perl_eval_pv() form is deprecated.

SV *       eval_pv(      const char *p, I32 croak_on_error)
SV *  Perl_eval_pv(pTHX_ const char *p, I32 croak_on_error)

#eval_sv

Tells Perl to eval the string in the SV. It supports the same flags as call_sv, with the obvious exception of G_EVAL. See perlcall.

The G_RETHROW flag can be used if you only need eval_sv() to execute code specified by a string, but not catch any errors.

By default the code is compiled and executed with the default hints, such as strict and features. Set G_USEHINTS in flags to use the current hints from PL_curcop.

NOTE: the perl_eval_sv() form is deprecated.

SSize_t       eval_sv(      SV *sv, I32 flags)
SSize_t  Perl_eval_sv(pTHX_ SV *sv, I32 flags)

#FREETMPS

Closing bracket for temporaries on a callback. See "SAVETMPS" and perlcall.

FREETMPS;

#G_DISCARD

#G_EVAL

#G_KEEPERR

#G_LIST

#G_NOARGS

#G_SCALAR

#G_VOID

Described in perlcall.

#GIMME

DEPRECATED! It is planned to remove GIMME from a future release of Perl. Do not use it for new code; remove it from existing code.

A backward-compatible version of GIMME_V which can only return G_SCALAR or G_LIST; in a void context, it returns G_SCALAR. Deprecated. Use GIMME_V instead.

U32  GIMME

#GIMME_V

The XSUB-writer's equivalent to Perl's wantarray. Returns G_VOID, G_SCALAR or G_LIST for void, scalar or list context, respectively. See perlcall for a usage example.

U32  GIMME_V

#is_lvalue_sub

Returns non-zero if the sub calling this function is being called in an lvalue context. Returns 0 otherwise.

I32       is_lvalue_sub()
I32  Perl_is_lvalue_sub(pTHX)

#LEAVE

Closing bracket on a callback. See "ENTER" and perlcall.

LEAVE;

#LEAVE_with_name

Same as "LEAVE", but when debugging is enabled it first checks that the scope has the given name. name must be a literal string.

LEAVE_with_name("name");

#mortal_destructor_sv

This function arranges for either a Perl code reference, or a C function reference to be called at the end of the current statement.

The coderef argument determines the type of function that will be called. If it is SvROK() it is assumed to be a reference to a CV and will arrange for the coderef to be called. If it is not SvROK() then it is assumed to be a SvIV() which is SvIOK() whose value is a pointer to a C function of type DESTRUCTORFUNC_t created using PTR2INT(). Either way the args parameter will be provided to the callback as a parameter, although the rules for doing so differ between the Perl and C mode. Normally this function is only used directly for the Perl case and the wrapper mortal_destructor_x() is used for the C function case.

When operating in Perl callback mode the args parameter may be NULL in which case the code reference is called with no arguments, otherwise if it is an AV (SvTYPE(args) == SVt_PVAV) then the contents of the AV will be used as the arguments to the code reference, and if it is any other type then the args SV will be provided as a single argument to the code reference.

When operating in a C callback mode the args parameter will be passed directly to the C function as a void * pointer. No additional processing of the argument will be performed, and it is the callers responsibility to free the args parameter if necessary.

Be aware that there is a significant difference in timing between the end of the current statement and the end of the current pseudo block. If you are looking for a mechanism to trigger a function at the end of the current pseudo block you should look at "SAVEDESTRUCTOR_X" in perlapi instead of this function.

void       mortal_destructor_sv(      SV *coderef, SV *args)
void  Perl_mortal_destructor_sv(pTHX_ SV *coderef, SV *args)

#MORTALDESTRUCTOR_SV

#MORTALSVFUNC_X

Described in perlguts.

MORTALDESTRUCTOR_SV(SV *coderef, SV *args)
MORTALSVFUNC_X     (SVFUNC_t f, SV *sv)

#PL_errgv

Described in perlcall.

#save_aelem

#save_aelem_flags

These each arrange for the value of the array element av[idx] to be restored at the end of the enclosing pseudo-block.

In save_aelem, the SV at C**sptr> will be replaced by a new undef scalar. That scalar will inherit any magic from the original **sptr, and any 'set' magic will be processed.

In save_aelem_flags, SAVEf_KEEPOLDELEM being set in flags causes the function to forgo all that: the scalar at **sptr is untouched. If SAVEf_KEEPOLDELEM is not set, the SV at C**sptr> will be replaced by a new undef scalar. That scalar will inherit any magic from the original **sptr. Any 'set' magic will be processed if and only if SAVEf_SETMAGIC is set in in flags.

void       save_aelem      (      AV *av, SSize_t idx, SV **sptr)
void       save_aelem_flags(      AV *av, SSize_t idx, SV **sptr,
                                  const U32 flags)
void  Perl_save_aelem_flags(pTHX_ AV *av, SSize_t idx, SV **sptr,
                                  const U32 flags)

#save_aptr

#save_ary

#save_hash

Described in perlguts.

void       save_aptr(      AV **aptr)
void  Perl_save_aptr(pTHX_ AV **aptr)
AV *       save_ary (      GV *gv)
AV *  Perl_save_ary (pTHX_ GV *gv)
HV *       save_hash(      GV *gv)
HV *  Perl_save_hash(pTHX_ GV *gv)

#save_helem

#save_helem_flags

These each arrange for the value of the hash element (in Perlish terms) $hv{key}] to be restored at the end of the enclosing pseudo-block.

In save_helem, the SV at C**sptr> will be replaced by a new undef scalar. That scalar will inherit any magic from the original **sptr, and any 'set' magic will be processed.

In save_helem_flags, SAVEf_KEEPOLDELEM being set in flags causes the function to forgo all that: the scalar at **sptr is untouched. If SAVEf_KEEPOLDELEM is not set, the SV at C**sptr> will be replaced by a new undef scalar. That scalar will inherit any magic from the original **sptr. Any 'set' magic will be processed if and only if SAVEf_SETMAGIC is set in in flags.

void       save_helem      (      HV *hv, SV *key, SV **sptr)
void       save_helem_flags(      HV *hv, SV *key, SV **sptr,
                                  const U32 flags)
void  Perl_save_helem_flags(pTHX_ HV *hv, SV *key, SV **sptr,
                                  const U32 flags)

#save_hptr

#save_item

#save_scalar

#save_svref

#SAVEBOOL

#SAVEDELETE

#SAVEDESTRUCTOR

#SAVEDESTRUCTOR_X

#SAVEFREEOP

#SAVEFREEPV

#SAVEFREERCPV

#SAVEFREESV

#SAVEGENERICSV

#SAVEINT

#SAVEIV

#SAVEI8

#SAVEI16

#SAVEI32

#SAVEMORTALIZESV

#SAVEPPTR

#SAVERCPV

#SAVESPTR

#SAVESTACK_POS

#SAVESTRLEN

Described in perlguts.

void       save_hptr       (      HV **hptr)
void  Perl_save_hptr       (pTHX_ HV **hptr)
void       save_item       (      SV *item)
void  Perl_save_item       (pTHX_ SV *item)
SV *       save_scalar     (      GV *gv)
SV *  Perl_save_scalar     (pTHX_ GV *gv)
SV *       save_svref      (      SV **sptr)
SV *  Perl_save_svref      (pTHX_ SV **sptr)
           SAVEBOOL        (      bool i)
           SAVEDELETE      (      HV * hv, char * key,
                                  I32 length)
           SAVEDESTRUCTOR  (      DESTRUCTORFUNC_NOCONTEXT_t f,
                                  void *p)
           SAVEDESTRUCTOR_X(      DESTRUCTORFUNC_t f, void *p)
           SAVEFREEOP      (      OP *op)
           SAVEFREEPV      (      char *pv)
           SAVEFREERCPV    (      char *pv)
           SAVEFREESV      (      SV* sv)
           SAVEGENERICSV   (      char **psv)
           SAVEINT         (      int i)
           SAVEIV          (      IV i)
           SAVEI8          (      I8 i)
           SAVEI16         (      I16 i)
           SAVEI32         (      I32 i)
           SAVEMORTALIZESV (      SV* sv)
           SAVEPPTR        (      char * p)
           SAVERCPV        (      char *pv)
           SAVESPTR        (      SV * s)
           SAVESTACK_POS   ()
           SAVESTRLEN      (      STRLEN i)

#SAVETMPS

Opening bracket for temporaries on a callback. See "FREETMPS" and perlcall.

SAVETMPS;

#Casting

#cBOOL

Cast-to-bool. When Perl was able to be compiled on pre-C99 compilers, a (bool) cast didn't necessarily do the right thing, so this macro was created (and made somewhat complicated to work around bugs in old compilers). Now, many years later, and C99 is used, this is no longer required, but is kept for backwards compatibility.

bool  cBOOL(bool expr)

#I_V

Cast an NV to IV while avoiding undefined C behavior

IV  I_V(NV what)

#I_32

Cast an NV to I32 while avoiding undefined C behavior

I32  I_32(NV what)

#INT2PTR

#PTRV

#PTR2IV

#PTR2nat

#PTR2NV

#PTR2ul

#PTR2UV

Described in perlguts.

type           INT2PTR(type, int value)
IV             PTR2IV (void * ptr)
IV             PTR2nat(void *)
NV             PTR2NV (void * ptr)
unsigned long  PTR2ul (void *)
UV             PTR2UV (void * ptr)

#U_V

Cast an NV to UV while avoiding undefined C behavior

UV  U_V(NV what)

#U_32

Cast an NV to U32 while avoiding undefined C behavior

U32  U_32(NV what)

#Character case changing

Perl uses "full" Unicode case mappings. This means that converting a single character to another case may result in a sequence of more than one character. For example, the uppercase of ß (LATIN SMALL LETTER SHARP S) is the two character sequence SS. This presents some complications The lowercase of all characters in the range 0..255 is a single character, and thus "toLOWER_L1" is furnished. But, toUPPER_L1 can't exist, as it couldn't return a valid result for all legal inputs. Instead "toUPPER_uvchr" has an API that does allow every possible legal result to be returned.) Likewise no other function that is crippled by not being able to give the correct results for the full range of possible inputs has been implemented here.

#toFOLD

#toFOLD_A

#toFOLD_utf8

#toFOLD_utf8_safe

#toFOLD_uvchr

These all return the foldcase of a character. "foldcase" is an internal case for /i pattern matching. If the foldcase of character A and the foldcase of character B are the same, they match caselessly; otherwise they don't.

The differences in the forms are what domain they operate on, and whether the input is specified as a code point (those forms with a cp parameter) or as a UTF-8 string (the others). In the latter case, the code point to use is the first one in the buffer of UTF-8 encoded code points, delineated by the arguments p .. e - 1.

toFOLD and toFOLD_A are synonyms of each other. They return the foldcase of any ASCII-range code point. In this range, the foldcase is identical to the lowercase. All other inputs are returned unchanged. Since these are macros, the input type may be any integral one, and the output will occupy the same number of bits as the input.

There is no toFOLD_L1 nor toFOLD_LATIN1 as the foldcase of some code points in the 0..255 range is above that range or consists of multiple characters. Instead use toFOLD_uvchr.

toFOLD_uvchr returns the foldcase of any Unicode code point. The return value is identical to that of toFOLD_A for input code points in the ASCII range. The foldcase of the vast majority of Unicode code points is the same as the code point itself. For these, and for code points above the legal Unicode maximum, this returns the input code point unchanged. It additionally stores the UTF-8 of the result into the buffer beginning at s, and its length in bytes into *lenp. The caller must have made s large enough to contain at least UTF8_MAXBYTES_CASE+1 bytes to avoid possible overflow.

NOTE: the foldcase of a code point may be more than one code point. The return value of this function is only the first of these. The entire foldcase is returned in s. To determine if the result is more than a single code point, you can do something like this:

uc = toFOLD_uvchr(cp, s, &len);
if (len > UTF8SKIP(s)) { is multiple code points }
else { is a single code point }

toFOLD_utf8 and toFOLD_utf8_safe are synonyms of each other. The only difference between these and toFOLD_uvchr is that the source for these is encoded in UTF-8, instead of being a code point. It is passed as a buffer starting at p, with e pointing to one byte beyond its end. The p buffer may certainly contain more than one code point; but only the first one (up through e - 1) is examined. If the UTF-8 for the input character is malformed in some way, the program may croak, or the function may return the REPLACEMENT CHARACTER, at the discretion of the implementation, and subject to change in future releases.

UV  toFOLD          (UV cp)
UV  toFOLD_A        (UV cp)
UV  toFOLD_utf8     (U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toFOLD_utf8_safe(U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toFOLD_uvchr    (UV cp, U8* s, STRLEN* lenp)

#toLOWER

#toLOWER_A

#toLOWER_LATIN1

#toLOWER_LC

#toLOWER_L1

#toLOWER_utf8

#toLOWER_utf8_safe

#toLOWER_uvchr

These all return the lowercase of a character. The differences are what domain they operate on, and whether the input is specified as a code point (those forms with a cp parameter) or as a UTF-8 string (the others). In the latter case, the code point to use is the first one in the buffer of UTF-8 encoded code points, delineated by the arguments p .. e - 1.

toLOWER and toLOWER_A are synonyms of each other. They return the lowercase of any uppercase ASCII-range code point. All other inputs are returned unchanged. Since these are macros, the input type may be any integral one, and the output will occupy the same number of bits as the input.

toLOWER_L1 and toLOWER_LATIN1 are synonyms of each other. They behave identically as toLOWER for ASCII-range input. But additionally will return the lowercase of any uppercase code point in the entire 0..255 range, assuming a Latin-1 encoding (or the EBCDIC equivalent on such platforms).

toLOWER_LC returns the lowercase of the input code point according to the rules of the current POSIX locale. Input code points outside the range 0..255 are returned unchanged.

toLOWER_uvchr returns the lowercase of any Unicode code point. The return value is identical to that of toLOWER_L1 for input code points in the 0..255 range. The lowercase of the vast majority of Unicode code points is the same as the code point itself. For these, and for code points above the legal Unicode maximum, this returns the input code point unchanged. It additionally stores the UTF-8 of the result into the buffer beginning at s, and its length in bytes into *lenp. The caller must have made s large enough to contain at least UTF8_MAXBYTES_CASE+1 bytes to avoid possible overflow.

NOTE: the lowercase of a code point may be more than one code point. The return value of this function is only the first of these. The entire lowercase is returned in s. To determine if the result is more than a single code point, you can do something like this:

uc = toLOWER_uvchr(cp, s, &len);
if (len > UTF8SKIP(s)) { is multiple code points }
else { is a single code point }

toLOWER_utf8 and toLOWER_utf8_safe are synonyms of each other. The only difference between these and toLOWER_uvchr is that the source for these is encoded in UTF-8, instead of being a code point. It is passed as a buffer starting at p, with e pointing to one byte beyond its end. The p buffer may certainly contain more than one code point; but only the first one (up through e - 1) is examined. If the UTF-8 for the input character is malformed in some way, the program may croak, or the function may return the REPLACEMENT CHARACTER, at the discretion of the implementation, and subject to change in future releases.

UV  toLOWER          (UV cp)
UV  toLOWER_A        (UV cp)
UV  toLOWER_LATIN1   (UV cp)
UV  toLOWER_LC       (UV cp)
UV  toLOWER_L1       (UV cp)
UV  toLOWER_utf8     (U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toLOWER_utf8_safe(U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toLOWER_uvchr    (UV cp, U8* s, STRLEN* lenp)

#toTITLE

#toTITLE_A

#toTITLE_utf8

#toTITLE_utf8_safe

#toTITLE_uvchr

These all return the titlecase of a character. The differences are what domain they operate on, and whether the input is specified as a code point (those forms with a cp parameter) or as a UTF-8 string (the others). In the latter case, the code point to use is the first one in the buffer of UTF-8 encoded code points, delineated by the arguments p .. e - 1.

toTITLE and toTITLE_A are synonyms of each other. They return the titlecase of any lowercase ASCII-range code point. In this range, the titlecase is identical to the uppercase. All other inputs are returned unchanged. Since these are macros, the input type may be any integral one, and the output will occupy the same number of bits as the input.

There is no toTITLE_L1 nor toTITLE_LATIN1 as the titlecase of some code points in the 0..255 range is above that range or consists of multiple characters. Instead use toTITLE_uvchr.

toTITLE_uvchr returns the titlecase of any Unicode code point. The return value is identical to that of toTITLE_A for input code points in the ASCII range. The titlecase of the vast majority of Unicode code points is the same as the code point itself. For these, and for code points above the legal Unicode maximum, this returns the input code point unchanged. It additionally stores the UTF-8 of the result into the buffer beginning at s, and its length in bytes into *lenp. The caller must have made s large enough to contain at least UTF8_MAXBYTES_CASE+1 bytes to avoid possible overflow.

NOTE: the titlecase of a code point may be more than one code point. The return value of this function is only the first of these. The entire titlecase is returned in s. To determine if the result is more than a single code point, you can do something like this:

uc = toTITLE_uvchr(cp, s, &len);
if (len > UTF8SKIP(s)) { is multiple code points }
else { is a single code point }

toTITLE_utf8 and toTITLE_utf8_safe are synonyms of each other. The only difference between these and toTITLE_uvchr is that the source for these is encoded in UTF-8, instead of being a code point. It is passed as a buffer starting at p, with e pointing to one byte beyond its end. The p buffer may certainly contain more than one code point; but only the first one (up through e - 1) is examined. If the UTF-8 for the input character is malformed in some way, the program may croak, or the function may return the REPLACEMENT CHARACTER, at the discretion of the implementation, and subject to change in future releases.

UV  toTITLE          (UV cp)
UV  toTITLE_A        (UV cp)
UV  toTITLE_utf8     (U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toTITLE_utf8_safe(U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toTITLE_uvchr    (UV cp, U8* s, STRLEN* lenp)

#toUPPER

#toUPPER_A

#toUPPER_utf8

#toUPPER_utf8_safe

#toUPPER_uvchr

These all return the uppercase of a character. The differences are what domain they operate on, and whether the input is specified as a code point (those forms with a cp parameter) or as a UTF-8 string (the others). In the latter case, the code point to use is the first one in the buffer of UTF-8 encoded code points, delineated by the arguments p .. e - 1.

toUPPER and toUPPER_A are synonyms of each other. They return the uppercase of any lowercase ASCII-range code point. All other inputs are returned unchanged. Since these are macros, the input type may be any integral one, and the output will occupy the same number of bits as the input.

There is no toUPPER_L1 nor toUPPER_LATIN1 as the uppercase of some code points in the 0..255 range is above that range or consists of multiple characters. Instead use toUPPER_uvchr.

toUPPER_uvchr returns the uppercase of any Unicode code point. The return value is identical to that of toUPPER_A for input code points in the ASCII range. The uppercase of the vast majority of Unicode code points is the same as the code point itself. For these, and for code points above the legal Unicode maximum, this returns the input code point unchanged. It additionally stores the UTF-8 of the result into the buffer beginning at s, and its length in bytes into *lenp. The caller must have made s large enough to contain at least UTF8_MAXBYTES_CASE+1 bytes to avoid possible overflow.

NOTE: the uppercase of a code point may be more than one code point. The return value of this function is only the first of these. The entire uppercase is returned in s. To determine if the result is more than a single code point, you can do something like this:

uc = toUPPER_uvchr(cp, s, &len);
if (len > UTF8SKIP(s)) { is multiple code points }
else { is a single code point }

toUPPER_utf8 and toUPPER_utf8_safe are synonyms of each other. The only difference between these and toUPPER_uvchr is that the source for these is encoded in UTF-8, instead of being a code point. It is passed as a buffer starting at p, with e pointing to one byte beyond its end. The p buffer may certainly contain more than one code point; but only the first one (up through e - 1) is examined. If the UTF-8 for the input character is malformed in some way, the program may croak, or the function may return the REPLACEMENT CHARACTER, at the discretion of the implementation, and subject to change in future releases.

UV  toUPPER          (UV cp)
UV  toUPPER_A        (UV cp)
UV  toUPPER_utf8     (U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toUPPER_utf8_safe(U8* p, U8* e, U8* s, STRLEN* lenp)
UV  toUPPER_uvchr    (UV cp, U8* s, STRLEN* lenp)

#Character classification

This section is about functions (really macros) that classify characters into types, such as punctuation versus alphabetic, etc. Most of these are analogous to regular expression character classes. (See "POSIX Character Classes" in perlrecharclass.) There are several variants for each class. (Not all macros have all variants; each item below lists the ones valid for it.) None are affected by use bytes, and only the ones with LC in the name are affected by the current locale.

The base function, e.g., isALPHA(), takes any signed or unsigned value, treating it as a code point, and returns a boolean as to whether or not the character represented by it is (or on non-ASCII platforms, corresponds to) an ASCII character in the named class based on platform, Unicode, and Perl rules. If the input is a number that doesn't fit in an octet, FALSE is returned.

Variant isFOO_A (e.g., isALPHA_A()) is identical to the base function with no suffix "_A". This variant is used to emphasize by its name that only ASCII-range characters can return TRUE.

Variant isFOO_L1 imposes the Latin-1 (or EBCDIC equivalent) character set onto the platform. That is, the code points that are ASCII are unaffected, since ASCII is a subset of Latin-1. But the non-ASCII code points are treated as if they are Latin-1 characters. For example, isWORDCHAR_L1() will return true when called with the code point 0xDF, which is a word character in both ASCII and EBCDIC (though it represents different characters in each). If the input is a number that doesn't fit in an octet, FALSE is returned. (Perl's documentation uses a colloquial definition of Latin-1, to include all code points below 256.)

Variant isFOO_uvchr is exactly like the isFOO_L1 variant, for inputs below 256, but if the code point is larger than 255, Unicode rules are used to determine if it is in the character class. For example, isWORDCHAR_uvchr(0x100) returns TRUE, since 0x100 is LATIN CAPITAL LETTER A WITH MACRON in Unicode, and is a word character.

Variants isFOO_utf8 and isFOO_utf8_safe are like isFOO_uvchr, but are used for UTF-8 encoded strings. The two forms are different names for the same thing. Each call to one of these classifies the first character of the string starting at p. The second parameter, e, points to anywhere in the string beyond the first character, up to one byte past the end of the entire string. Although both variants are identical, the suffix _safe in one name emphasizes that it will not attempt to read beyond e - 1, provided that the constraint s < e is true (this is asserted for in -DDEBUGGING builds). If the UTF-8 for the input character is malformed in some way, the program may croak, or the function may return FALSE, at the discretion of the implementation, and subject to change in future releases.

Variant isFOO_LC is like the isFOO_A and isFOO_L1 variants, but the result is based on the current locale, which is what LC in the name stands for. If Perl can determine that the current locale is a UTF-8 locale, it uses the published Unicode rules; otherwise, it uses the C library function that gives the named classification. For example, isDIGIT_LC() when not in a UTF-8 locale returns the result of calling isdigit(). FALSE is always returned if the input won't fit into an octet. On some platforms where the C library function is known to be defective, Perl changes its result to follow the POSIX standard's rules.

Variant isFOO_LC_uvchr acts exactly like isFOO_LC for inputs less than 256, but for larger ones it returns the Unicode classification of the code point.

Variants isFOO_LC_utf8 and isFOO_LC_utf8_safe are like isFOO_LC_uvchr, but are used for UTF-8 encoded strings. The two forms are different names for the same thing. Each call to one of these classifies the first character of the string starting at p. The second parameter, e, points to anywhere in the string beyond the first character, up to one byte past the end of the entire string. Although both variants are identical, the suffix _safe in one name emphasizes that it will not attempt to read beyond e - 1, provided that the constraint s < e is true (this is asserted for in -DDEBUGGING builds). If the UTF-8 for the input character is malformed in some way, the program may croak, or the function may return FALSE, at the discretion of the implementation, and subject to change in future releases.

#isALNUM

#isALNUM_A

#isALNUM_LC

#isALNUM_LC_uvchr

These are each a synonym for their respectively named "isWORDCHAR" variant.

They are provided for backward compatibility, even though a word character includes more than the standard C language meaning of alphanumeric. To get the C language definition, use the corresponding "isALPHANUMERIC" variant.

bool  isALNUM         (UV ch)
bool  isALNUM_A       (UV ch)
bool  isALNUM_LC      (UV ch)
bool  isALNUM_LC_uvchr(UV ch)

#isALNUMC

#isALNUMC_A

#isALNUMC_LC

#isALNUMC_LC_uvchr

#isALNUMC_L1

These are discouraged, backward compatibility macros for "isALPHANUMERIC". That is, each returns a boolean indicating whether the specified character is one of [A-Za-z0-9], analogous to m/[[:alnum:]]/.

The C suffix in the names was meant to indicate that they correspond to the C language isalnum(3).

bool  isALNUMC         (UV ch)
bool  isALNUMC_A       (UV ch)
bool  isALNUMC_LC      (UV ch)
bool  isALNUMC_LC_uvchr(UV ch)
bool  isALNUMC_L1      (UV ch)

#isALPHA

#isALPHA_A

#isALPHA_LC

#isALPHA_LC_utf8_safe

#isALPHA_LC_uvchr

#isALPHA_L1

#isALPHA_utf8

#isALPHA_utf8_safe

#isALPHA_uvchr

Returns a boolean indicating whether the specified input is one of [A-Za-z], analogous to m/[[:alpha:]]/. See the top of this section for an explanation of the variants.

bool  isALPHA             (UV ch)
bool  isALPHA_A           (UV ch)
bool  isALPHA_LC          (UV ch)
bool  isALPHA_LC_utf8_safe(U8 * s, U8 *end)
bool  isALPHA_LC_uvchr    (UV ch)
bool  isALPHA_L1          (UV ch)
bool  isALPHA_utf8        (U8 * s, U8 * end)
bool  isALPHA_utf8_safe   (U8 * s, U8 * end)
bool  isALPHA_uvchr       (UV ch)

#isALPHANUMERIC

#isALPHANUMERIC_A

#isALPHANUMERIC_LC

#isALPHANUMERIC_LC_utf8_safe

#isALPHANUMERIC_LC_uvchr

#isALPHANUMERIC_L1

#isALPHANUMERIC_utf8

#isALPHANUMERIC_utf8_safe

#isALPHANUMERIC_uvchr

Returns a boolean indicating whether the specified character is one of [A-Za-z0-9], analogous to m/[[:alnum:]]/. See the top of this section for an explanation of the variants.

bool  isALPHANUMERIC             (UV ch)
bool  isALPHANUMERIC_A           (UV ch)
bool  isALPHANUMERIC_LC          (UV ch)
bool  isALPHANUMERIC_LC_utf8_safe(U8 * s, U8 *end)
bool  isALPHANUMERIC_LC_uvchr    (UV ch)
bool  isALPHANUMERIC_L1          (UV ch)
bool  isALPHANUMERIC_utf8        (U8 * s, U8 * end)
bool  isALPHANUMERIC_utf8_safe   (U8 * s, U8 * end)
bool  isALPHANUMERIC_uvchr       (UV ch)

#isASCII

#isASCII_A

#isASCII_LC

#isASCII_LC_utf8_safe

#isASCII_LC_uvchr

#isASCII_L1

#isASCII_utf8

#isASCII_utf8_safe

#isASCII_uvchr

Returns a boolean indicating whether the specified character is one of the 128 characters in the ASCII character set, analogous to m/[[:ascii:]]/. On non-ASCII platforms, it returns TRUE iff this character corresponds to an ASCII character. Variants isASCII_A() and isASCII_L1() are identical to isASCII(). See the top of this section for an explanation of the variants. Note, however, that some platforms do not have the C library routine isascii(). In these cases, the variants whose names contain LC are the same as the corresponding ones without.

Also note, that because all ASCII characters are UTF-8 invariant (meaning they have the exact same representation (always a single byte) whether encoded in UTF-8 or not), isASCII will give the correct results when called with any byte in any string encoded or not in UTF-8. And similarly isASCII_utf8 and isASCII_utf8_safe will work properly on any string encoded or not in UTF-8.

bool  isASCII             (UV ch)
bool  isASCII_A           (UV ch)
bool  isASCII_LC          (UV ch)
bool  isASCII_LC_utf8_safe(U8 * s, U8 *end)
bool  isASCII_LC_uvchr    (UV ch)
bool  isASCII_L1          (UV ch)
bool  isASCII_utf8        (U8 * s, U8 * end)
bool  isASCII_utf8_safe   (U8 * s, U8 * end)
bool  isASCII_uvchr       (UV ch)

#isBLANK

#isBLANK_A

#isBLANK_LC

#isBLANK_LC_utf8_safe

#isBLANK_LC_uvchr

#isBLANK_L1

#isBLANK_utf8

#isBLANK_utf8_safe

#isBLANK_uvchr

Returns a boolean indicating whether the specified character is a character considered to be a blank, analogous to m/[[:blank:]]/. See the top of this section for an explanation of the variants. Note, however, that some platforms do not have the C library routine isblank(). In these cases, the variants whose names contain LC are the same as the corresponding ones without.

bool  isBLANK             (UV ch)
bool  isBLANK_A           (UV ch)
bool  isBLANK_LC          (UV ch)
bool  isBLANK_LC_utf8_safe(U8 * s, U8 *end)
bool  isBLANK_LC_uvchr    (UV ch)
bool  isBLANK_L1          (UV ch)
bool  isBLANK_utf8        (U8 * s, U8 * end)
bool  isBLANK_utf8_safe   (U8 * s, U8 * end)
bool  isBLANK_uvchr       (UV ch)

#isCNTRL

#isCNTRL_A

#isCNTRL_LC

#isCNTRL_LC_utf8_safe

#isCNTRL_LC_uvchr

#isCNTRL_L1

#isCNTRL_utf8

#isCNTRL_utf8_safe

#isCNTRL_uvchr

Returns a boolean indicating whether the specified character is a control character, analogous to m/[[:cntrl:]]/. See the top of this section for an explanation of the variants. On EBCDIC platforms, you almost always want to use the isCNTRL_L1 variant.

bool  isCNTRL             (UV ch)
bool  isCNTRL_A           (UV ch)
bool  isCNTRL_LC          (UV ch)
bool  isCNTRL_LC_utf8_safe(U8 * s, U8 *end)
bool  isCNTRL_LC_uvchr    (UV ch)
bool  isCNTRL_L1          (UV ch)
bool  isCNTRL_utf8        (U8 * s, U8 * end)
bool  isCNTRL_utf8_safe   (U8 * s, U8 * end)
bool  isCNTRL_uvchr       (UV ch)

#isDIGIT

#isDIGIT_A

#isDIGIT_LC

#isDIGIT_LC_utf8_safe

#isDIGIT_LC_uvchr

#isDIGIT_L1

#isDIGIT_utf8

#isDIGIT_utf8_safe

#isDIGIT_uvchr

Returns a boolean indicating whether the specified character is a digit, analogous to m/[[:digit:]]/. Variants isDIGIT_A and isDIGIT_L1 are identical to isDIGIT. See the top of this section for an explanation of the variants.

bool  isDIGIT             (UV ch)
bool  isDIGIT_A           (UV ch)
bool  isDIGIT_LC          (UV ch)
bool  isDIGIT_LC_utf8_safe(U8 * s, U8 *end)
bool  isDIGIT_LC_uvchr    (UV ch)
bool  isDIGIT_L1          (UV ch)
bool  isDIGIT_utf8        (U8 * s, U8 * end)
bool  isDIGIT_utf8_safe   (U8 * s, U8 * end)
bool  isDIGIT_uvchr       (UV ch)

#isGRAPH

#isGRAPH_A

#isGRAPH_LC

#isGRAPH_LC_utf8_safe

#isGRAPH_LC_uvchr

#isGRAPH_L1

#isGRAPH_utf8

#isGRAPH_utf8_safe

#isGRAPH_uvchr

Returns a boolean indicating whether the specified character is a graphic character, analogous to m/[[:graph:]]/. See the top of this section for an explanation of the variants.

bool  isGRAPH             (UV ch)
bool  isGRAPH_A           (UV ch)
bool  isGRAPH_LC          (UV ch)
bool  isGRAPH_LC_utf8_safe(U8 * s, U8 *end)
bool  isGRAPH_LC_uvchr    (UV ch)
bool  isGRAPH_L1          (UV ch)
bool  isGRAPH_utf8        (U8 * s, U8 * end)
bool  isGRAPH_utf8_safe   (U8 * s, U8 * end)
bool  isGRAPH_uvchr       (UV ch)

#isIDCONT

#isIDCONT_A

#isIDCONT_LC

#isIDCONT_LC_utf8_safe

#isIDCONT_LC_uvchr

#isIDCONT_L1

#isIDCONT_utf8

#isIDCONT_utf8_safe

#isIDCONT_uvchr

Returns a boolean indicating whether the specified character can be the second or succeeding character of an identifier. This is very close to, but not quite the same as the official Unicode property XID_Continue. The difference is that this returns true only if the input character also matches "isWORDCHAR". See the top of this section for an explanation of the variants.

bool  isIDCONT             (UV ch)
bool  isIDCONT_A           (UV ch)
bool  isIDCONT_LC          (UV ch)
bool  isIDCONT_LC_utf8_safe(U8 * s, U8 *end)
bool  isIDCONT_LC_uvchr    (UV ch)
bool  isIDCONT_L1          (UV ch)
bool  isIDCONT_utf8        (U8 * s, U8 * end)
bool  isIDCONT_utf8_safe   (U8 * s, U8 * end)
bool  isIDCONT_uvchr       (UV ch)

#isIDFIRST

#isIDFIRST_A

#isIDFIRST_LC

#isIDFIRST_LC_utf8_safe

#isIDFIRST_LC_uvchr

#isIDFIRST_L1

#isIDFIRST_utf8

#isIDFIRST_utf8_safe

#isIDFIRST_uvchr

Returns a boolean indicating whether the specified character can be the first character of an identifier. This is very close to, but not quite the same as the official Unicode property XID_Start. The difference is that this returns true only if the input character also matches "isWORDCHAR". See the top of this section for an explanation of the variants.

bool  isIDFIRST             (UV ch)
bool  isIDFIRST_A           (UV ch)
bool  isIDFIRST_LC          (UV ch)
bool  isIDFIRST_LC_utf8_safe(U8 * s, U8 *end)
bool  isIDFIRST_LC_uvchr    (UV ch)
bool  isIDFIRST_L1          (UV ch)
bool  isIDFIRST_utf8        (U8 * s, U8 * end)
bool  isIDFIRST_utf8_safe   (U8 * s, U8 * end)
bool  isIDFIRST_uvchr       (UV ch)

#isLOWER

#isLOWER_A

#isLOWER_LC

#isLOWER_LC_utf8_safe

#isLOWER_LC_uvchr

#isLOWER_L1

#isLOWER_utf8

#isLOWER_utf8_safe

#isLOWER_uvchr

Returns a boolean indicating whether the specified character is a lowercase character, analogous to m/[[:lower:]]/. See the top of this section for an explanation of the variants

bool  isLOWER             (UV ch)
bool  isLOWER_A           (UV ch)
bool  isLOWER_LC          (UV ch)
bool  isLOWER_LC_utf8_safe(U8 * s, U8 *end)
bool  isLOWER_LC_uvchr    (UV ch)
bool  isLOWER_L1          (UV ch)
bool  isLOWER_utf8        (U8 * s, U8 * end)
bool  isLOWER_utf8_safe   (U8 * s, U8 * end)
bool  isLOWER_uvchr       (UV ch)

#isOCTAL

#isOCTAL_A

#isOCTAL_L1

Returns a boolean indicating whether the specified character is an octal digit, [0-7]. The only two variants are isOCTAL_A and isOCTAL_L1; each is identical to isOCTAL.

bool  isOCTAL   (UV ch)
bool  isOCTAL_A (UV ch)
bool  isOCTAL_L1(UV ch)

#isPRINT

#isPRINT_A

#isPRINT_LC

#isPRINT_LC_utf8_safe

#isPRINT_LC_uvchr

#isPRINT_L1

#isPRINT_utf8

#isPRINT_utf8_safe

#isPRINT_uvchr

Returns a boolean indicating whether the specified character is a printable character, analogous to m/[[:print:]]/. See the top of this section for an explanation of the variants.

bool  isPRINT             (UV ch)
bool  isPRINT_A           (UV ch)
bool  isPRINT_LC          (UV ch)
bool  isPRINT_LC_utf8_safe(U8 * s, U8 *end)
bool  isPRINT_LC_uvchr    (UV ch)
bool  isPRINT_L1          (UV ch)
bool  isPRINT_utf8        (U8 * s, U8 * end)
bool  isPRINT_utf8_safe   (U8 * s, U8 * end)
bool  isPRINT_uvchr       (UV ch)

#isPSXSPC

#isPSXSPC_A

#isPSXSPC_LC

#isPSXSPC_LC_utf8_safe

#isPSXSPC_LC_uvchr

#isPSXSPC_L1

#isPSXSPC_utf8

#isPSXSPC_utf8_safe

#isPSXSPC_uvchr

(short for Posix Space) Starting in 5.18, this is identical in all its forms to the corresponding isSPACE() macros. The locale forms of this macro are identical to their corresponding isSPACE() forms in all Perl releases. In releases prior to 5.18, the non-locale forms differ from their isSPACE() forms only in that the isSPACE() forms don't match a Vertical Tab, and the isPSXSPC() forms do. Otherwise they are identical. Thus this macro is analogous to what m/[[:space:]]/ matches in a regular expression. See the top of this section for an explanation of the variants.

bool  isPSXSPC             (UV ch)
bool  isPSXSPC_A           (UV ch)
bool  isPSXSPC_LC          (UV ch)
bool  isPSXSPC_LC_utf8_safe(U8 * s, U8 *end)
bool  isPSXSPC_LC_uvchr    (UV ch)
bool  isPSXSPC_L1          (UV ch)
bool  isPSXSPC_utf8        (U8 * s, U8 * end)
bool  isPSXSPC_utf8_safe   (U8 * s, U8 * end)
bool  isPSXSPC_uvchr       (UV ch)

#isPUNCT

#isPUNCT_A

#isPUNCT_LC

#isPUNCT_LC_utf8_safe

#isPUNCT_LC_uvchr

#isPUNCT_L1

#isPUNCT_utf8

#isPUNCT_utf8_safe

#isPUNCT_uvchr

Returns a boolean indicating whether the specified character is a punctuation character, analogous to m/[[:punct:]]/. Note that the definition of what is punctuation isn't as straightforward as one might desire. See "POSIX Character Classes" in perlrecharclass for details. See the top of this section for an explanation of the variants.

bool  isPUNCT             (UV ch)
bool  isPUNCT_A           (UV ch)
bool  isPUNCT_LC          (UV ch)
bool  isPUNCT_LC_utf8_safe(U8 * s, U8 *end)
bool  isPUNCT_LC_uvchr    (UV ch)
bool  isPUNCT_L1          (UV ch)
bool  isPUNCT_utf8        (U8 * s, U8 * end)
bool  isPUNCT_utf8_safe   (U8 * s, U8 * end)
bool  isPUNCT_uvchr       (UV ch)

#isSPACE

#isSPACE_A

#isSPACE_LC

#isSPACE_LC_utf8_safe

#isSPACE_LC_uvchr

#isSPACE_L1

#isSPACE_utf8

#isSPACE_utf8_safe

#isSPACE_uvchr

Returns a boolean indicating whether the specified character is a whitespace character. This is analogous to what m/\s/ matches in a regular expression. Starting in Perl 5.18 this also matches what m/[[:space:]]/ does. Prior to 5.18, only the locale forms of this macro (the ones with LC in their names) matched precisely what m/[[:space:]]/ does. In those releases, the only difference, in the non-locale variants, was that isSPACE() did not match a vertical tab. (See "isPSXSPC" for a macro that matches a vertical tab in all releases.) See the top of this section for an explanation of the variants.

bool  isSPACE             (UV ch)
bool  isSPACE_A           (UV ch)
bool  isSPACE_LC          (UV ch)
bool  isSPACE_LC_utf8_safe(U8 * s, U8 *end)
bool  isSPACE_LC_uvchr    (UV ch)
bool  isSPACE_L1          (UV ch)
bool  isSPACE_utf8        (U8 * s, U8 * end)
bool  isSPACE_utf8_safe   (U8 * s, U8 * end)
bool  isSPACE_uvchr       (UV ch)

#isUPPER

#isUPPER_A

#isUPPER_LC

#isUPPER_LC_utf8_safe

#isUPPER_LC_uvchr

#isUPPER_L1

#isUPPER_utf8

#isUPPER_utf8_safe

#isUPPER_uvchr

Returns a boolean indicating whether the specified character is an uppercase character, analogous to m/[[:upper:]]/. See the top of this section for an explanation of the variants.

bool  isUPPER             (UV ch)
bool  isUPPER_A           (UV ch)
bool  isUPPER_LC          (UV ch)
bool  isUPPER_LC_utf8_safe(U8 * s, U8 *end)
bool  isUPPER_LC_uvchr    (UV ch)
bool  isUPPER_L1          (UV ch)
bool  isUPPER_utf8        (U8 * s, U8 * end)
bool  isUPPER_utf8_safe   (U8 * s, U8 * end)
bool  isUPPER_uvchr       (UV ch)

#isWORDCHAR

#isWORDCHAR_A

#isWORDCHAR_LC

#isWORDCHAR_LC_utf8_safe

#isWORDCHAR_LC_uvchr

#isWORDCHAR_L1

#isWORDCHAR_utf8

#isWORDCHAR_utf8_safe

#isWORDCHAR_uvchr

Returns a boolean indicating whether the specified character is a character that is a word character, analogous to what m/\w/ and m/[[:word:]]/ match in a regular expression. A word character is an alphabetic character, a decimal digit, a connecting punctuation character (such as an underscore), or a "mark" character that attaches to one of those (like some sort of accent).

See the top of this section for an explanation of the variants.

isWORDCHAR_A, isWORDCHAR_L1, isWORDCHAR_uvchr, isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8, and isWORDCHAR_LC_utf8_safe are also as described there, but additionally include the platform's native underscore.

bool  isWORDCHAR             (UV ch)
bool  isWORDCHAR_A           (UV ch)
bool  isWORDCHAR_LC          (UV ch)
bool  isWORDCHAR_LC_utf8_safe(U8 * s, U8 *end)
bool  isWORDCHAR_LC_uvchr    (UV ch)
bool  isWORDCHAR_L1          (UV ch)
bool  isWORDCHAR_utf8        (U8 * s, U8 * end)
bool  isWORDCHAR_utf8_safe   (U8 * s, U8 * end)
bool  isWORDCHAR_uvchr       (UV ch)

#isXDIGIT

#isXDIGIT_A

#isXDIGIT_LC

#isXDIGIT_LC_utf8_safe

#isXDIGIT_LC_uvchr

#isXDIGIT_L1

#isXDIGIT_utf8

#isXDIGIT_utf8_safe

#isXDIGIT_uvchr

Returns a boolean indicating whether the specified character is a hexadecimal digit. In the ASCII range these are [0-9A-Fa-f]. Variants isXDIGIT_A() and isXDIGIT_L1() are identical to isXDIGIT(). See the top of this section for an explanation of the variants.

bool  isXDIGIT             (UV ch)
bool  isXDIGIT_A           (UV ch)
bool  isXDIGIT_LC          (UV ch)
bool  isXDIGIT_LC_utf8_safe(U8 * s, U8 *end)
bool  isXDIGIT_LC_uvchr    (UV ch)
bool  isXDIGIT_L1          (UV ch)
bool  isXDIGIT_utf8        (U8 * s, U8 * end)
bool  isXDIGIT_utf8_safe   (U8 * s, U8 * end)
bool  isXDIGIT_uvchr       (UV ch)

#Compiler and Preprocessor information

#CPPLAST

This symbol is intended to be used along with CPPRUN in the same manner symbol CPPMINUS is used with CPPSTDIN. It contains either "-" or "".

#CPPMINUS

This symbol contains the second part of the string which will invoke the C preprocessor on the standard input and produce to standard output. This symbol will have the value "-" if CPPSTDIN needs a minus to specify standard input, otherwise the value is "".

#CPPRUN

This symbol contains the string which will invoke a C preprocessor on the standard input and produce to standard output. It needs to end with CPPLAST, after all other preprocessor flags have been specified. The main difference with CPPSTDIN is that this program will never be a pointer to a shell wrapper, i.e. it will be empty if no preprocessor is available directly to the user. Note that it may well be different from the preprocessor used to compile the C program.

#CPPSTDIN

This symbol contains the first part of the string which will invoke the C preprocessor on the standard input and produce to standard output. Typical value of "cc -E" or "/lib/cpp", but it can also call a wrapper. See "CPPRUN".

#HAS_BUILTIN_ADD_OVERFLOW

This symbol, if defined, indicates that the compiler supports __builtin_add_overflow for adding integers with overflow checks.

#HAS_BUILTIN_CHOOSE_EXPR

Can we handle GCC builtin for compile-time ternary-like expressions

#HAS_BUILTIN_EXPECT

Can we handle GCC builtin for telling that certain values are more likely

#HAS_BUILTIN_MUL_OVERFLOW

This symbol, if defined, indicates that the compiler supports __builtin_mul_overflow for multiplying integers with overflow checks.

#HAS_BUILTIN_SUB_OVERFLOW

This symbol, if defined, indicates that the compiler supports __builtin_sub_overflow for subtracting integers with overflow checks.

#HAS_C99_VARIADIC_MACROS

If defined, the compiler supports C99 variadic macros.

#HAS_STATIC_INLINE

This symbol, if defined, indicates that the C compiler supports C99-style static inline. That is, the function can't be called from another translation unit.

#HASATTRIBUTE_ALWAYS_INLINE

Can we handle GCC attribute for functions that should always be inlined.

#HASATTRIBUTE_DEPRECATED

Can we handle GCC attribute for marking deprecated APIs

#HASATTRIBUTE_FORMAT

Can we handle GCC attribute for checking printf-style formats

#HASATTRIBUTE_NONNULL

Can we handle GCC attribute for nonnull function parms.

#HASATTRIBUTE_NORETURN

Can we handle GCC attribute for functions that do not return

#HASATTRIBUTE_PURE

Can we handle GCC attribute for pure functions

#HASATTRIBUTE_UNUSED

Can we handle GCC attribute for unused variables and arguments

#HASATTRIBUTE_VISIBILITY

Can we handle GCC attribute for functions that should have a different visibility.

#HASATTRIBUTE_WARN_UNUSED_RESULT

Can we handle GCC attribute for warning on unused results

#MEM_ALIGNBYTES

This symbol contains the number of bytes required to align a double, or a long double when applicable. Usual values are 2, 4 and 8. The default is eight, for safety. For cross-compiling or multiarch support, Configure will set a minimum of 8.

#PERL_STATIC_INLINE

This symbol gives the best-guess incantation to use for static inline functions. If HAS_STATIC_INLINE is defined, this will give C99-style inline. If HAS_STATIC_INLINE is not defined, this will give a plain 'static'. It will always be defined to something that gives static linkage. Possibilities include

static inline       (c99)
static __inline__   (gcc -ansi)
static __inline     (MSVC)
static _inline      (older MSVC)
static              (c89 compilers)

#PERL_THREAD_LOCAL

This symbol, if defined, gives a linkage specification for thread-local storage. For example, for a C11 compiler this will be _Thread_local. Beware, some compilers are sensitive to the C language standard they are told to parse. For example, suncc defaults to C11, so our probe will report that _Thread_local can be used. However, if the -std=c99 is later added to the compiler flags, then _Thread_local will become a syntax error. Hence it is important for these flags to be consistent between probing and use.

#U32_ALIGNMENT_REQUIRED

This symbol, if defined, indicates that you must access character data through U32-aligned pointers.

#Compiler directives

#__ASSERT_

This is a helper macro to avoid preprocessor issues, replaced by nothing unless under DEBUGGING, where it expands to an assert of its argument, followed by a comma (hence the comma operator). If we just used a straight assert(), we would get a comma with nothing before it when not DEBUGGING.

__ASSERT_(bool expr)

#ASSUME

ASSUME is like assert(), but it has a benefit in a release build. It is a hint to a compiler about a statement of fact in a function call free expression, which allows the compiler to generate better machine code. In a debug build, ASSUME(x) is a synonym for assert(x). ASSUME(0) means the control path is unreachable. In a for loop, ASSUME can be used to hint that a loop will run at least X times. ASSUME is based off MSVC's __assume intrinsic function, see its documents for more details.

ASSUME(bool expr)

#dNOOP

Declare nothing; typically used as a placeholder to replace something that used to declare something. Works on compilers that require declarations before any code.

dNOOP;

#END_EXTERN_C

When not compiling using C++, expands to nothing. Otherwise ends a section of code already begun by a "START_EXTERN_C".

#EXTERN_C

When not compiling using C++, expands to nothing. Otherwise is used in a declaration of a function to indicate the function should have external C linkage. This is required for things to work for just about all functions with external linkage compiled into perl. Often, you can use "START_EXTERN_C" ... "END_EXTERN_C" blocks surrounding all your code that you need to have this linkage.

Example usage:

EXTERN_C int flock(int fd, int op);

#LIKELY

Returns the input unchanged, but at the same time it gives a branch prediction hint to the compiler that this condition is likely to be true.

LIKELY(bool expr)

#NOOP

Do nothing; typically used as a placeholder to replace something that used to do something.

NOOP;

#PERL_UNUSED_ARG

This is used to suppress compiler warnings that a parameter to a function is not used. This situation can arise, for example, when a parameter is needed under some configuration conditions, but not others, so that C preprocessor conditional compilation causes it be used just sometimes.

PERL_UNUSED_ARG(void x);

#PERL_UNUSED_CONTEXT

This is used to suppress compiler warnings that the thread context parameter to a function is not used. This situation can arise, for example, when a C preprocessor conditional compilation causes it be used just some times.

PERL_UNUSED_CONTEXT;

#PERL_UNUSED_DECL

Tells the compiler that the parameter in the function prototype just before it is not necessarily expected to be used in the function. Not that many compilers understand this, so this should only be used in cases where "PERL_UNUSED_ARG" can't conveniently be used.

Example usage:

Signal_t
Perl_perly_sighandler(int sig, Siginfo_t *sip PERL_UNUSED_DECL,
                      void *uap PERL_UNUSED_DECL, bool safe)

#PERL_UNUSED_RESULT

This macro indicates to discard the return value of the function call inside it, e.g.,

PERL_UNUSED_RESULT(foo(a, b))

The main reason for this is that the combination of gcc -Wunused-result (part of -Wall) and the __attribute__((warn_unused_result)) cannot be silenced with casting to void. This causes trouble when the system header files use the attribute.

Use PERL_UNUSED_RESULT sparingly, though, since usually the warning is there for a good reason: you might lose success/failure information, or leak resources, or changes in resources.

But sometimes you just want to ignore the return value, e.g., on codepaths soon ending up in abort, or in "best effort" attempts, or in situations where there is no good way to handle failures.

Sometimes PERL_UNUSED_RESULT might not be the most natural way: another possibility is that you can capture the return value and use "PERL_UNUSED_VAR" on that.

PERL_UNUSED_RESULT(void x)

#PERL_UNUSED_VAR

This is used to suppress compiler warnings that the variable x is not used. This situation can arise, for example, when a C preprocessor conditional compilation causes it be used just some times.

PERL_UNUSED_VAR(void x);

#START_EXTERN_C

When not compiling using C++, expands to nothing. Otherwise begins a section of code in which every function will effectively have "EXTERN_C" applied to it, that is to have external C linkage. The section is ended by a "END_EXTERN_C".

#STATIC

Described in perlguts.

#STMT_START

#STMT_END

These allow a series of statements in a macro to be used as a single statement, as in

if (x) STMT_START { ... } STMT_END else ...

Note that you can't return a value out of this construct and cannot use it as an operand to the comma operator. These limit its utility.

But, a value could be returned by constructing the API so that a pointer is passed and the macro dereferences this to set the return. If the value can be any of various types, depending on context, you can handle that situation in some situations by adding the type of the return as an extra accompanying parameter:

#define foo(param, type)  STMT_START {
                             type * param; *param = do_calc; ...
                          } STMT_END

This could be awkward, so consider instead using a C language static inline function.

If you do use this construct, it is easy to forget that it is a macro and not a function, and hence fall into traps that might not show up until someone someday writes code which contains names that clash with the ones you chose here, or calls it with a parameter which is an expression with side effects, the consequences of which you didn't think about. See "Writing safer macros" in perlhacktips for how to avoid these.

#UNLIKELY

Returns the input unchanged, but at the same time it gives a branch prediction hint to the compiler that this condition is likely to be false.

UNLIKELY(bool expr)

#Compile-time scope hooks

#BhkDISABLE

NOTE: BhkDISABLE is experimental and may change or be removed without notice.

Temporarily disable an entry in this BHK structure, by clearing the appropriate flag. which is a preprocessor token indicating which entry to disable.

void  BhkDISABLE(BHK *hk, token which)

#BhkENABLE

NOTE: BhkENABLE is experimental and may change or be removed without notice.

Re-enable an entry in this BHK structure, by setting the appropriate flag. which is a preprocessor token indicating which entry to enable. This will assert (under -DDEBUGGING) if the entry doesn't contain a valid pointer.

void  BhkENABLE(BHK *hk, token which)

#BhkENTRY_set

NOTE: BhkENTRY_set is experimental and may change or be removed without notice.

Set an entry in the BHK structure, and set the flags to indicate it is valid. which is a preprocessing token indicating which entry to set. The type of ptr depends on the entry.

void  BhkENTRY_set(BHK *hk, token which, void *ptr)

#blockhook_register

NOTE: blockhook_register is experimental and may change or be removed without notice.

Register a set of hooks to be called when the Perl lexical scope changes at compile time. See "Compile-time scope hooks" in perlguts.

void  Perl_blockhook_register(pTHX_ BHK *hk)

#Concurrency

#aTHX

#aTHX_

Described in perlguts.

#CPERLscope

DEPRECATED! It is planned to remove CPERLscope from a future release of Perl. Do not use it for new code; remove it from existing code.

Now a no-op.

void  CPERLscope(void x)

#dTHR

#dTHX

Described in perlguts.

#dTHXa

On threaded perls, set pTHX to a; on unthreaded perls, do nothing

#dTHXoa

Now a synonym for "dTHXa".

#dVAR

This is now a synonym for dNOOP: declare nothing

#GETENV_PRESERVES_OTHER_THREAD

This symbol, if defined, indicates that the getenv system call doesn't zap the static buffer of getenv() in a different thread. The typical getenv() implementation will return a pointer to the proper position in **environ. But some may instead copy them to a static buffer in getenv(). If there is a per-thread instance of that buffer, or the return points to **environ, then a many-reader/1-writer mutex will work; otherwise an exclusive locking mutex is required to prevent races.

#HAS_PTHREAD_ATFORK

This symbol, if defined, indicates that the pthread_atfork routine is available to setup fork handlers.

#HAS_PTHREAD_ATTR_SETSCOPE

This symbol, if defined, indicates that the pthread_attr_setscope system call is available to set the contention scope attribute of a thread attribute object.

#HAS_PTHREAD_YIELD

This symbol, if defined, indicates that the pthread_yield routine is available to yield the execution of the current thread. sched_yield is preferable to pthread_yield.

#HAS_SCHED_YIELD

This symbol, if defined, indicates that the sched_yield routine is available to yield the execution of the current thread. sched_yield is preferable to pthread_yield.

#I_MACH_CTHREADS

This symbol, if defined, indicates to the C program that it should include mach/cthreads.h.

#ifdef I_MACH_CTHREADS
    #include <mach_cthreads.h>
#endif

#I_PTHREAD

This symbol, if defined, indicates to the C program that it should include pthread.h.

#ifdef I_PTHREAD
    #include <pthread.h>
#endif

#MULTIPLICITY

This symbol, if defined, indicates that Perl should be built to use multiplicity.

#OLD_PTHREAD_CREATE_JOINABLE

This symbol, if defined, indicates how to create pthread in joinable (aka undetached) state. NOTE: not defined if pthread.h already has defined PTHREAD_CREATE_JOINABLE (the new version of the constant). If defined, known values are PTHREAD_CREATE_UNDETACHED and __UNDETACHED.

#OLD_PTHREADS_API

This symbol, if defined, indicates that Perl should be built to use the old draft POSIX threads API.

#PERL_IMPLICIT_CONTEXT

#PERL_NO_GET_CONTEXT

#pTHX

#pTHX_

Described in perlguts.

#SCHED_YIELD

This symbol defines the way to yield the execution of the current thread. Known ways are sched_yield, pthread_yield, and pthread_yield with NULL.

#COPs and Hint Hashes

#cop_fetch_label

NOTE: cop_fetch_label is experimental and may change or be removed without notice.

Returns the label attached to a cop, and stores its length in bytes into *len. Upon return, *flags will be set to either SVf_UTF8 or 0.

Alternatively, use the macro "CopLABEL_len_flags"; or if you don't need to know if the label is UTF-8 or not, the macro "CopLABEL_len"; or if you additionally don't need to know the length, "CopLABEL".

const char *       cop_fetch_label(      COP * const cop,
                                         STRLEN *len, U32 *flags)
const char *  Perl_cop_fetch_label(pTHX_ COP * const cop,
                                         STRLEN *len, U32 *flags)

#cop_hints_exists_pv

#cop_hints_exists_pvn

#cop_hints_exists_pvs

#cop_hints_exists_sv

These look up the hint entry in the cop cop with the key specified by key (and keylen in the pvn form), returning true if a value exists, and false otherwise.

The forms differ in how the key is specified. In all forms, the key is pointed to by key. In the plain pv form, the key is a C language NUL-terminated string. In the pvs form, the key is a C language string literal. In the pvn form, an additional parameter, keylen, specifies the length of the string, which hence, may contain embedded-NUL characters. In the sv form, *key is an SV, and the key is the PV extracted from that. using "SvPV_const".

hash is a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from the pvs form, as it is computed automatically at compile time.

The only flag currently used from the flags parameter is COPHH_KEY_UTF8. It is illegal to set this in the sv form. In the pv* forms, it specifies whether the key octets are interpreted as UTF-8 (if set) or as Latin-1 (if cleared). The sv form uses the underlying SV to determine the UTF-8ness of the octets.

bool  cop_hints_exists_pv (const COP *cop, const char *key,
                           U32 hash, U32 flags)
bool  cop_hints_exists_pvn(const COP *cop, const char *key,
                           STRLEN keylen, U32 hash, U32 flags)
bool  cop_hints_exists_pvs(const COP *cop, "key", U32 flags)
bool  cop_hints_exists_sv (const COP *cop, SV *key, U32 hash,
                           U32 flags)

#cop_hints_fetch_pv

#cop_hints_fetch_pvn

#cop_hints_fetch_pvs

#cop_hints_fetch_sv

These look up the hint entry in the cop cop with the key specified by key (and keylen in the pvn form), returning that value as a mortal scalar copy, or &PL_sv_placeholder if there is no value associated with the key.

The forms differ in how the key is specified. In the plain pv form, the key is a C language NUL-terminated string. In the pvs form, the key is a C language string literal. In the pvn form, an additional parameter, keylen, specifies the length of the string, which hence, may contain embedded-NUL characters. In the sv form, *key is an SV, and the key is the PV extracted from that. using "SvPV_const".

hash is a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from the pvs form, as it is computed automatically at compile time.

The only flag currently used from the flags parameter is COPHH_KEY_UTF8. It is illegal to set this in the sv form. In the pv* forms, it specifies whether the key octets are interpreted as UTF-8 (if set) or as Latin-1 (if cleared). The sv form uses the underlying SV to determine the UTF-8ness of the octets.

SV *  cop_hints_fetch_pv (const COP *cop, const char *key,
                          U32 hash, U32 flags)
SV *  cop_hints_fetch_pvn(const COP *cop, const char *key,
                          STRLEN keylen, U32 hash, U32 flags)
SV *  cop_hints_fetch_pvs(const COP *cop, "key", U32 flags)
SV *  cop_hints_fetch_sv (const COP *cop, SV *key, U32 hash,
                          U32 flags)

#cop_hints_2hv

Generates and returns a standard Perl hash representing the full set of hint entries in the cop cop. flags is currently unused and must be zero.

HV *  cop_hints_2hv(const COP *cop, U32 flags)

#cop_store_label

NOTE: cop_store_label is experimental and may change or be removed without notice.

Save a label into a cop_hints_hash. You need to set flags to SVf_UTF8 for a UTF-8 label. Any other flag is ignored.

void       cop_store_label(      COP * const cop,
                                 const char *label, STRLEN len,
                                 U32 flags)
void  Perl_cop_store_label(pTHX_ COP * const cop,
                                 const char *label, STRLEN len,
                                 U32 flags)

#CopFILE

Returns the name of the file associated with the COP c

const char *  CopFILE(const COP * c)

#CopFILE_copy

Efficiently copies the cop file name from one COP to another. Wraps the required logic to do a refcounted copy under threads or not.

void  CopFILE_copy(COP * dst, COP * src)

#CopFILE_free

Frees the file data in a cop. Under the hood this is a refcounting operation.

void  CopFILE_free(COP * c)

#CopFILE_LEN

Returns the length of the file associated with the COP c

const char *  CopFILE_LEN(const COP * c)

#CopFILE_set

#CopFILE_setn

These each make pv the name of the file associated with the COP c. In the plain CopFILE_set form, pv is a C language NUL-terminated string. In CopFILE_setn, len is the length of pv, which hence may contain embedded NUL characters.

void  CopFILE_set (COP * c, const char * pv)
void  CopFILE_setn(COP * c, const char * pv, STRLEN len)

#CopFILEAV

Returns the AV associated with the COP c, creating it if necessary.

AV *  CopFILEAV(const COP * c)

#CopFILEAVn

Returns the AV associated with the COP c, returning NULL if it doesn't already exist.

AV *  CopFILEAVn(const COP * c)

#CopFILEGV

Returns the GV associated with the COP c

GV *  CopFILEGV(const COP * c)

#CopFILEGV_set

Available only on unthreaded perls. Makes pv the name of the file associated with the COP c

void  CopFILEGV_set(COP *c, GV *gv)

#CopFILESV

Returns the SV associated with the COP c

SV *  CopFILESV(const COP * c)

#cophh_copy

NOTE: cophh_copy is experimental and may change or be removed without notice.

Make and return a complete copy of the cop hints hash cophh.

COPHH *  cophh_copy(COPHH *cophh)

#cophh_delete_pv

#cophh_delete_pvn

#cophh_delete_pvs

#cophh_delete_sv

NOTE: all these forms are experimental and may change or be removed without notice.

These delete a key and its associated value from the cop hints hash cophh, and return the modified hash. The returned hash pointer is in general not the same as the hash pointer that was passed in. The input hash is consumed by the function, and the pointer to it must not be subsequently used. Use "cophh_copy" if you need both hashes.

The forms differ in how the key is specified. In all forms, the key is pointed to by key. In the plain pv form, the key is a C language NUL-terminated string. In the pvs form, the key is a C language string literal. In the pvn form, an additional parameter, keylen, specifies the length of the string, which hence, may contain embedded-NUL characters. In the sv form, *key is an SV, and the key is the PV extracted from that. using "SvPV_const".

hash is a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from the pvs form, as it is computed automatically at compile time.

The only flag currently used from the flags parameter is COPHH_KEY_UTF8. It is illegal to set this in the sv form. In the pv* forms, it specifies whether the key octets are interpreted as UTF-8 (if set) or as Latin-1 (if cleared). The sv form uses the underlying SV to determine the UTF-8ness of the octets.

COPHH *  cophh_delete_pv (COPHH *cophh, const char *key,
                          U32 hash, U32 flags)
COPHH *  cophh_delete_pvn(COPHH *cophh, const char *key,
                          STRLEN keylen, U32 hash, U32 flags)
COPHH *  cophh_delete_pvs(COPHH *cophh, "key", U32 flags)
COPHH *  cophh_delete_sv (COPHH *cophh, SV *key, U32 hash,
                          U32 flags)

#cophh_exists_pvn

NOTE: cophh_exists_pvn is experimental and may change or be removed without notice.

These look up the hint entry in the cop cop with the key specified by key (and keylen in the pvn form), returning true if a value exists, and false otherwise.

The forms differ in how the key is specified. In the plain pv form, the key is a C language NUL-terminated string. In the pvs form, the key is a C language string literal. In the pvn form, an additional parameter, keylen, specifies the length of the string, which hence, may contain embedded-NUL characters. In the sv form, *key is an SV, and the key is the PV extracted from that. using "SvPV_const".

hash is a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from the pvs form, as it is computed automatically at compile time.

The only flag currently used from the flags parameter is COPHH_KEY_UTF8. It is illegal to set this in the sv form. In the pv* forms, it specifies whether the key octets are interpreted as UTF-8 (if set) or as Latin-1 (if cleared). The sv form uses the underlying SV to determine the UTF-8ness of the octets.

bool  cophh_exists_pvn(const COPHH *cophh, const char *key,
                       STRLEN keylen, U32 hash, U32 flags)

#cophh_fetch_pv

#cophh_fetch_pvn

#cophh_fetch_pvs

#cophh_fetch_sv

NOTE: all these forms are experimental and may change or be removed without notice.

These look up the entry in the cop hints hash cophh with the key specified by key (and keylen in the pvn form), returning that value as a mortal scalar copy, or &PL_sv_placeholder if there is no value associated with the key.

The forms differ in how the key is specified. In the plain pv form, the key is a C language NUL-terminated string. In the pvs form, the key is a C language string literal. In the pvn form, an additional parameter, keylen, specifies the length of the string, which hence, may contain embedded-NUL characters. In the sv form, *key is an SV, and the key is the PV extracted from that. using "SvPV_const".

hash is a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from the pvs form, as it is computed automatically at compile time.

The only flag currently used from the flags parameter is COPHH_KEY_UTF8. It is illegal to set this in the sv form. In the pv* forms, it specifies whether the key octets are interpreted as UTF-8 (if set) or as Latin-1 (if cleared). The sv form uses the underlying SV to determine the UTF-8ness of the octets.

SV *  cophh_fetch_pv (const COPHH *cophh, const char *key,
                      U32 hash, U32 flags)
SV *  cophh_fetch_pvn(const COPHH *cophh, const char *key,
                      STRLEN keylen, U32 hash, U32 flags)
SV *  cophh_fetch_pvs(const COPHH *cophh, "key", U32 flags)
SV *  cophh_fetch_sv (const COPHH *cophh, SV *key, U32 hash,
                      U32 flags)

#cophh_free

NOTE: cophh_free is experimental and may change or be removed without notice.

Discard the cop hints hash cophh, freeing all resources associated with it.

void  cophh_free(COPHH *cophh)

#cophh_new_empty

NOTE: cophh_new_empty is experimental and may change or be removed without notice.

Generate and return a fresh cop hints hash containing no entries.

COPHH *  cophh_new_empty()

#cophh_store_pv

#cophh_store_pvn

#cophh_store_pvs

#cophh_store_sv

NOTE: all these forms are experimental and may change or be removed without notice.

These store a value, associated with a key, in the cop hints hash cophh, and return the modified hash. The returned hash pointer is in general not the same as the hash pointer that was passed in. The input hash is consumed by the function, and the pointer to it must not be subsequently used. Use "cophh_copy" if you need both hashes.

value is the scalar value to store for this key. value is copied by these functions, which thus do not take ownership of any reference to it, and hence later changes to the scalar will not be reflected in the value visible in the cop hints hash. Complex types of scalar will not be stored with referential integrity, but will be coerced to strings.

The forms differ in how the key is specified. In all forms, the key is pointed to by key. In the plain pv form, the key is a C language NUL-terminated string. In the pvs form, the key is a C language string literal. In the pvn form, an additional parameter, keylen, specifies the length of the string, which hence, may contain embedded-NUL characters. In the sv form, *key is an SV, and the key is the PV extracted from that. using "SvPV_const".

hash is a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from the pvs form, as it is computed automatically at compile time.

The only flag currently used from the flags parameter is COPHH_KEY_UTF8. It is illegal to set this in the sv form. In the pv* forms, it specifies whether the key octets are interpreted as UTF-8 (if set) or as Latin-1 (if cleared). The sv form uses the underlying SV to determine the UTF-8ness of the octets.

COPHH *  cophh_store_pv (COPHH *cophh, const char *key, U32 hash,
                         SV *value, U32 flags)
COPHH *  cophh_store_pvn(COPHH *cophh, const char *key,
                         STRLEN keylen, U32 hash, SV *value,
                         U32 flags)
COPHH *  cophh_store_pvs(COPHH *cophh, "key", SV *value,
                         U32 flags)
COPHH *  cophh_store_sv (COPHH *cophh, SV *key, U32 hash,
                         SV *value, U32 flags)

#cophh_2hv

NOTE: cophh_2hv is experimental and may change or be removed without notice.

Generates and returns a standard Perl hash representing the full set of key/value pairs in the cop hints hash cophh. flags is currently unused and must be zero.

HV *  cophh_2hv(const COPHH *cophh, U32 flags)

#CopLABEL

#CopLABEL_len

#CopLABEL_len_flags

These return the label attached to a cop.

CopLABEL_len and CopLABEL_len_flags additionally store the number of bytes comprising the returned label into *len.

CopLABEL_len_flags additionally returns the UTF-8ness of the returned label, by setting *flags to 0 or SVf_UTF8.

const char *  CopLABEL          (COP *const cop)
const char *  CopLABEL_len      (COP *const cop, STRLEN *len)
const char *  CopLABEL_len_flags(COP *const cop, STRLEN *len,
                                 U32 *flags)

#CopLINE

Returns the line number in the source code associated with the COP c

line_t  CopLINE(const COP * c)

#CopSTASH

Returns the stash associated with c.

HV *  CopSTASH(const COP * c)

#CopSTASH_eq

Returns a boolean as to whether or not hv is the stash associated with c.

bool  CopSTASH_eq(const COP * c, const HV * hv)

#CopSTASH_set

Set the stash associated with c to hv.

bool  CopSTASH_set(COP * c, HV * hv)

#CopSTASHPV

Returns the package name of the stash associated with c, or NULL if no associated stash

char *  CopSTASHPV(const COP * c)

#CopSTASHPV_set

Set the package name of the stash associated with c, to the NUL-terminated C string p, creating the package if necessary.

void  CopSTASHPV_set(COP * c, const char * pv)

#PERL_SI

Use this typedef to declare variables that are to hold struct stackinfo.

#PL_curcop

The currently active COP (control op) roughly representing the current statement in the source.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

COP*  PL_curcop

#RCPV_LEN

Returns the length of a pv created with rcpv_new(). Note that this reflects the length of the string from the callers point of view, it does not include the mandatory null which is always injected at the end of the string by rcpv_new(). No checks are performed to ensure that pv was actually allocated with rcpv_new(), it is the callers responsibility to ensure that this is the case.

RCPV *  RCPV_LEN(char *pv)

#RCPV_REFCNT_dec

Decrements the refcount for a char * pointer which was created with a call to rcpv_new(). Same as calling rcpv_free(). No checks are performed to ensure that pv was actually allocated with rcpv_new(), it is the callers responsibility to ensure that this is the case.

RCPV *  RCPV_REFCNT_dec(char *pv)

#RCPV_REFCNT_inc

Increments the refcount for a char * pointer which was created with a call to rcpv_new(). Same as calling rcpv_copy(). No checks are performed to ensure that pv was actually allocated with rcpv_new(), it is the callers responsibility to ensure that this is the case.

RCPV *  RCPV_REFCNT_inc(char *pv)

#RCPV_REFCOUNT

Returns the refcount for a pv created with rcpv_new(). No checks are performed to ensure that pv was actually allocated with rcpv_new(), it is the callers responsibility to ensure that this is the case.

RCPV *  RCPV_REFCOUNT(char *pv)

#RCPVx

Returns the RCPV structure (struct rcpv) for a refcounted string pv created with rcpv_new(). No checks are performed to ensure that pv was actually allocated with rcpv_new(), it is the callers responsibility to ensure that this is the case.

RCPV *  RCPVx(char *pv)

#Custom Operators

#custom_op_register

Register a custom op. See "Custom Operators" in perlguts.

void  Perl_custom_op_register(pTHX_ Perl_ppaddr_t ppaddr,
                                    const XOP *xop)

#Perl_custom_op_xop

Return the XOP structure for a given custom op. This macro should be considered internal to OP_NAME and the other access macros: use them instead. This macro does call a function. Prior to 5.19.6, this was implemented as a function.

const XOP *  Perl_custom_op_xop(const OP *o)

#XopDISABLE

Temporarily disable a member of the XOP, by clearing the appropriate flag.

void  XopDISABLE(XOP *xop, token which)

#XopENABLE

Reenable a member of the XOP which has been disabled.

void  XopENABLE(XOP *xop, token which)

#XopENTRY

Return a member of the XOP structure. which is a cpp token indicating which entry to return. If the member is not set this will return a default value. The return type depends on which. This macro evaluates its arguments more than once. If you are using Perl_custom_op_xop to retrieve a XOP * from a OP *, use the more efficient "XopENTRYCUSTOM" instead.

XopENTRY(XOP *xop, token which)

#XopENTRY_set

Set a member of the XOP structure. which is a cpp token indicating which entry to set. See "Custom Operators" in perlguts for details about the available members and how they are used. This macro evaluates its argument more than once.

void  XopENTRY_set(XOP *xop, token which, value)

#XopENTRYCUSTOM

Exactly like XopENTRY(XopENTRY(Perl_custom_op_xop(aTHX_ o), which) but more efficient. The which parameter is identical to "XopENTRY".

XopENTRYCUSTOM(const OP *o, token which)

#XopFLAGS

Return the XOP's flags.

U32  XopFLAGS(XOP *xop)

#CV Handling

This section documents functions to manipulate CVs which are code-values, meaning subroutines. For more information, see perlguts.

#caller_cx

The XSUB-writer's equivalent of caller(). The returned PERL_CONTEXT structure can be interrogated to find all the information returned to Perl by caller. Note that XSUBs don't get a stack frame, so caller_cx(0, NULL) will return information for the immediately-surrounding Perl code.

This function skips over the automatic calls to &DB::sub made on the behalf of the debugger. If the stack frame requested was a sub called by DB::sub, the return value will be the frame for the call to DB::sub, since that has the correct line number/etc. for the call site. If dbcxp is non-NULL, it will be set to a pointer to the frame for the sub call itself.

const PERL_CONTEXT *       caller_cx(I32 level,
                                      const PERL_CONTEXT **dbcxp)
const PERL_CONTEXT *  Perl_caller_cx(pTHX_ I32 level,
                                      const PERL_CONTEXT **dbcxp)

#CvDEPTH

Returns the recursion level of the CV sv. Hence >= 2 indicates we are in a recursive call.

I32 *       CvDEPTH(const CV * const sv)
I32 *  Perl_CvDEPTH(const CV * const sv)

#CvGV

Returns the GV associated with the CV sv, reifying it if necessary.

GV *       CvGV(      CV *sv)
GV *  Perl_CvGV(pTHX_ CV *sv)

#CvREFCNT_inc

#CvREFCNT_inc_simple

#CvREFCNT_inc_simple_NN

These all increment the reference count of the given SV, which must be a CV. They are useful when assigning the result into a typed pointer as they avoid the need to cast the result to the appropriate type.

CV *  CvREFCNT_inc          (CV *cv)
CV *  CvREFCNT_inc_simple   (CV *cv)
CV *  CvREFCNT_inc_simple_NN(CV *cv)

#CvSTASH

Returns the stash of the CV. A stash is the symbol table hash, containing the package-scoped variables in the package where the subroutine was defined. For more information, see perlguts.

This also has a special use with XS AUTOLOAD subs. See "Autoloading with XSUBs" in perlguts.

HV*  CvSTASH(CV* cv)

#find_runcv

Locate the CV corresponding to the currently executing sub or eval. If db_seqp is non_null, skip CVs that are in the DB package and populate *db_seqp with the cop sequence number at the point that the DB:: code was entered. (This allows debuggers to eval in the scope of the breakpoint rather than in the scope of the debugger itself.)

CV *       find_runcv(      U32 *db_seqp)
CV *  Perl_find_runcv(pTHX_ U32 *db_seqp)

#get_cv

#get_cvn_flags

#get_cvs

These return the CV of the specified Perl subroutine. flags are passed to gv_fetchpvn_flags. If GV_ADD is set and the Perl subroutine does not exist then it will be declared (which has the same effect as saying sub name;). If GV_ADD is not set and the subroutine does not exist, then NULL is returned.

The forms differ only in how the subroutine is specified.. With get_cvs, the name is a literal C string, enclosed in double quotes. With get_cv, the name is given by the name parameter, which must be a NUL-terminated C string. With get_cvn_flags, the name is also given by the name parameter, but it is a Perl string (possibly containing embedded NUL bytes), and its length in bytes is contained in the len parameter.

NOTE: the perl_get_cv() form is deprecated.

CV *       get_cv       (      const char *name, I32 flags)
CV *  Perl_get_cv       (pTHX_ const char *name, I32 flags)
CV *       get_cvn_flags(      const char *name, STRLEN len,
                               I32 flags)
CV *  Perl_get_cvn_flags(pTHX_ const char *name, STRLEN len,
                               I32 flags)
CV *       get_cvs      (      "name", I32 flags)

#Nullcv

DEPRECATED! It is planned to remove Nullcv from a future release of Perl. Do not use it for new code; remove it from existing code.

Null CV pointer.

(deprecated - use (CV *)NULL instead)

#Debugging

#av_dump

Dumps the contents of an AV to the STDERR filehandle, Similar to using Devel::Peek on an arrayref but does not expect an RV wrapper. Dumps contents to a depth of 3 levels deep.

void       av_dump(      AV *av)
void  Perl_av_dump(pTHX_ AV *av)

#deb

#deb_nocontext

#vdeb

When perl is compiled with -DDEBUGGING, these each print to STDERR the information given by the arguments, prefaced by the name of the file containing the script causing the call, and the line number within that file.

If the v (verbose) debugging option is in effect, the process id is also printed.

deb and deb_nocontext differ only in that deb_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

vdeb is the same as deb except args are an encapsulated argument list.

void  Perl_deb          (pTHX_ const char *pat, ...)
void       deb_nocontext(      const char *pat, ...)
void  Perl_deb_nocontext(      const char *pat, ...)
void       vdeb         (      const char *pat, va_list *args)
void  Perl_vdeb         (pTHX_ const char *pat, va_list *args)

#debstack

Dump the current stack

I32       debstack()
I32  Perl_debstack(pTHX)

#dump_all

Dumps the entire optree of the current program starting at PL_main_root to STDERR. Also dumps the optrees for all visible subroutines in PL_defstash.

void       dump_all()
void  Perl_dump_all(pTHX)

#dump_c_backtrace

Dumps the C backtrace to the given fp.

Returns true if a backtrace could be retrieved, false if not.

bool       dump_c_backtrace(      PerlIO *fp, int max_depth,
                                  int skip)
bool  Perl_dump_c_backtrace(pTHX_ PerlIO *fp, int max_depth,
                                  int skip)

#dump_eval

Described in perlguts.

void       dump_eval()
void  Perl_dump_eval(pTHX)

#dump_form

Dumps the contents of the format contained in the GV gv to STDERR, or a message that one doesn't exist.

void       dump_form(      const GV *gv)
void  Perl_dump_form(pTHX_ const GV *gv)

#dump_packsubs

Dumps the optrees for all visible subroutines in stash.

void       dump_packsubs(      const HV *stash)
void  Perl_dump_packsubs(pTHX_ const HV *stash)

#dump_sub

Described in perlguts.

void       dump_sub(      const GV *gv)
void  Perl_dump_sub(pTHX_ const GV *gv)

#get_c_backtrace_dump

Returns a SV containing a dump of depth frames of the call stack, skipping the skip innermost ones. depth of 20 is usually enough.

The appended output looks like:

...
1   10e004812:0082   Perl_croak   util.c:1716    /usr/bin/perl
2   10df8d6d2:1d72   perl_parse   perl.c:3975    /usr/bin/perl
...

The fields are tab-separated. The first column is the depth (zero being the innermost non-skipped frame). In the hex:offset, the hex is where the program counter was in S_parse_body, and the :offset (might be missing) tells how much inside the S_parse_body the program counter was.

The util.c:1716 is the source code file and line number.

The /usr/bin/perl is obvious (hopefully).

Unknowns are "-". Unknowns can happen unfortunately quite easily: if the platform doesn't support retrieving the information; if the binary is missing the debug information; if the optimizer has transformed the code by for example inlining.

SV *       get_c_backtrace_dump(      int max_depth, int skip)
SV *  Perl_get_c_backtrace_dump(pTHX_ int max_depth, int skip)

#gv_dump

Dump the name and, if they differ, the effective name of the GV gv to STDERR.

void       gv_dump(      GV *gv)
void  Perl_gv_dump(pTHX_ GV *gv)

#HAS_BACKTRACE

This symbol, if defined, indicates that the backtrace() routine is available to get a stack trace. The execinfo.h header must be included to use this routine.

#hv_dump

Dumps the contents of an HV to the STDERR filehandle. Similar to using Devel::Peek on an hashref but does not expect an RV wrapper. Dumps contents to a depth of 3 levels deep.

void       hv_dump(      HV *hv)
void  Perl_hv_dump(pTHX_ HV *hv)

#magic_dump

Dumps the contents of the MAGIC mg to STDERR.

void       magic_dump(      const MAGIC *mg)
void  Perl_magic_dump(pTHX_ const MAGIC *mg)

#op_class

Given an op, determine what type of struct it has been allocated as. Returns one of the OPclass enums, such as OPclass_LISTOP.

OPclass       op_class(      const OP *o)
OPclass  Perl_op_class(pTHX_ const OP *o)

#op_dump

Dumps the optree starting at OP o to STDERR.

void       op_dump(      const OP *o)
void  Perl_op_dump(pTHX_ const OP *o)

#opdump_printf

Prints formatted output to STDERR according to the pattern and subsequent arguments, in the style of printf() et.al. This should only be called by a function invoked by the xop_dump field of a custom operator, where the ctx opaque structure pointer should be passed in from the argument given to the xop_dump callback.

This function handles indentation after linefeeds, so message strings passed in should not account for it themselves. Multiple lines may be passed to this function at once, or a single line may be split across multiple calls.

void  Perl_opdump_printf(pTHX_ struct Perl_OpDumpContext *ctx,
                               const char *pat, ...)

#PL_op

Described in perlhacktips.

#PL_runops

Described in perlguts.

runops_proc_t  PL_runops

#PL_sv_serial

Described in perlhacktips.

#pmop_dump

Dump an OP that is related to Pattern Matching, such as s/foo/bar/; these require special handling.

void       pmop_dump(      PMOP *pm)
void  Perl_pmop_dump(pTHX_ PMOP *pm)

#sv_dump

#sv_dump_depth

These each dump the contents of an SV to the STDERR filehandle.

sv_dump_depth is a more flexible variant of sv_dump, taking an extra parameter giving the maximum depth to dump.

sv_dump is limited to dumping items to a depth of 4 if the item is an SvROK, and dumping only the top level item otherwise. This means that it will not dump the contents of an AV * or HV *. For that use "av_dump" or "hv_dump".

For an example of its output, see Devel::Peek.

In contrast, sv_dump_depth can be used on any SV derived type (GV, HV, AV) with an appropriate cast:

HV *hv = ...;
sv_dump_depth((SV*)hv, 2);

would dump the hv, its keys and values, but would not recurse into any RV values.

void       sv_dump      (      SV *sv)
void  Perl_sv_dump      (pTHX_ SV *sv)
void       sv_dump_depth(      SV *sv, I32 depth)
void  Perl_sv_dump_depth(pTHX_ SV *sv, I32 depth)

#vdeb*

Described under "deb"

#Display functions

#form

#form_nocontext

#vform

These each take a sprintf-style format pattern and conventional (non-SV) arguments and return the formatted string.

(char *) form(const char* pat, ...)

They can be used any place a string (char *) is required:

char * s = form_nocontext("%d.%d", major, minor);

They each return a temporary that will be freed "soon", automatically by the system, at the same time that SVs operated on by "sv_2mortal" are freed.

Use the result immediately, or copy to a stable place for longer retention. This is contrary to the incorrect previous documentation of these that claimed that the return was a single per-thread buffer. That was (and is) actually true only when these are called during global destruction.

form and form_nocontext differ only in that form_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context (and can be called without the Perl_ prefix.

vform is the same as form except the arguments are an encapsulated argument list. It does need a thread context parameter, but that is supplied automatically when called without the Perl_ prefix.

char *  Perl_form          (pTHX_ const char *pat, ...)
char *       form_nocontext(      const char *pat, ...)
char *  Perl_form_nocontext(      const char *pat, ...)
char *       vform         (      const char *pat, va_list *args)
char *  Perl_vform         (pTHX_ const char *pat, va_list *args)

#mess

#mess_nocontext

#vmess

These each take a sprintf-style format pattern and argument list, which are used to generate a string message. If the message does not end with a newline, then it will be extended with some indication of the current location in the code, as described for "mess_sv".

mess and mess_nocontext differ only in that mess_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

vmess is the same as mess except the arguments are an encapsulated argument list. It needs a thread context parameter only when called with the Perl_ prefix.

Normally, the resulting message is returned in a new mortal SV. But during global destruction a single SV may be shared between uses of this function.

SV *  Perl_mess          (pTHX_ const char *pat, ...)
SV *       mess_nocontext(      const char *pat, ...)
SV *  Perl_mess_nocontext(      const char *pat, ...)
SV *       vmess         (      const char *pat, va_list *args)
SV *  Perl_vmess         (pTHX_ const char *pat, va_list *args)

#mess_sv

Expands a message, intended for the user, to include an indication of the current location in the code, if the message does not already appear to be complete.

basemsg is the initial message or object. If it is a reference, it will be used as-is and will be the result of this function. Otherwise it is used as a string, and if it already ends with a newline, it is taken to be complete, and the result of this function will be the same string. If the message does not end with a newline, then a segment such as at foo.pl line 37 will be appended, and possibly other clauses indicating the current state of execution. The resulting message will end with a dot and a newline.

Normally, the resulting message is returned in a new mortal SV. During global destruction a single SV may be shared between uses of this function. If consume is true, then the function is permitted (but not required) to modify and return basemsg instead of allocating a new SV.

SV *       mess_sv(      SV *basemsg, bool consume)
SV *  Perl_mess_sv(pTHX_ SV *basemsg, bool consume)

#pv_display

Similar to

pv_escape(dsv,pv,cur,pvlim,PERL_PV_ESCAPE_QUOTE);

except that an additional "\0" will be appended to the string when len > cur and pv[cur] is "\0".

Note that the final string may be up to 7 chars longer than pvlim.

char *       pv_display(      SV *dsv, const char *pv,
                              STRLEN cur, STRLEN len,
                              STRLEN pvlim)
char *  Perl_pv_display(pTHX_ SV *dsv, const char *pv,
                              STRLEN cur, STRLEN len,
                              STRLEN pvlim)

#pv_escape

Escapes at most the first count chars of pv and puts the results into dsv such that the size of the escaped string will not exceed max chars and will not contain any incomplete escape sequences. The number of bytes escaped will be returned in the STRLEN *escaped parameter if it is not null. When the dsv parameter is null no escaping actually occurs, but the number of bytes that would be escaped were it not null will be calculated.

If flags contains PERL_PV_ESCAPE_QUOTE then any double quotes in the string will also be escaped.

Normally the SV will be cleared before the escaped string is prepared, but when PERL_PV_ESCAPE_NOCLEAR is set this will not occur.

If PERL_PV_ESCAPE_UNI is set then the input string is treated as UTF-8. If PERL_PV_ESCAPE_UNI_DETECT is set then the input string is scanned using is_utf8_string() to determine if it is UTF-8.

If PERL_PV_ESCAPE_ALL is set then all input chars will be output using \x01F1 style escapes, otherwise if PERL_PV_ESCAPE_NONASCII is set, only non-ASCII chars will be escaped using this style; otherwise, only chars above 255 will be so escaped; other non printable chars will use octal or common escaped patterns like \n. Otherwise, if PERL_PV_ESCAPE_NOBACKSLASH then all chars below 255 will be treated as printable and will be output as literals. The PERL_PV_ESCAPE_NON_WC modifies the previous rules to cause word chars, unicode or otherwise, to be output as literals, note this uses the *unicode* rules for deciding on word characters.

If PERL_PV_ESCAPE_FIRSTCHAR is set then only the first char of the string will be escaped, regardless of max. If the output is to be in hex, then it will be returned as a plain hex sequence. Thus the output will either be a single char, an octal escape sequence, a special escape like \n or a hex value.

If PERL_PV_ESCAPE_RE is set then the escape char used will be a "%" and not a "\\". This is because regexes very often contain backslashed sequences, whereas "%" is not a particularly common character in patterns.

Returns a pointer to the escaped text as held by dsv.

char *       pv_escape(      SV *dsv, char const * const str,
                             const STRLEN count, STRLEN max,
                             STRLEN * const escaped, U32 flags)
char *  Perl_pv_escape(pTHX_ SV *dsv, char const * const str,
                             const STRLEN count, STRLEN max,
                             STRLEN * const escaped, U32 flags)

#pv_pretty

Converts a string into something presentable, handling escaping via pv_escape() and supporting quoting and ellipses.

If the PERL_PV_PRETTY_QUOTE flag is set then the result will be double quoted with any double quotes in the string escaped. Otherwise if the PERL_PV_PRETTY_LTGT flag is set then the result be wrapped in angle brackets.

If the PERL_PV_PRETTY_ELLIPSES flag is set and not all characters in string were output then an ellipsis ... will be appended to the string. Note that this happens AFTER it has been quoted.

If start_color is non-null then it will be inserted after the opening quote (if there is one) but before the escaped text. If end_color is non-null then it will be inserted after the escaped text but before any quotes or ellipses.

Returns a pointer to the prettified text as held by dsv.

char *       pv_pretty(      SV *dsv, char const * const str,
                             const STRLEN count,
                             const STRLEN max,
                             char const * const start_color,
                             char const * const end_color,
                             const U32 flags)
char *  Perl_pv_pretty(pTHX_ SV *dsv, char const * const str,
                             const STRLEN count,
                             const STRLEN max,
                             char const * const start_color,
                             char const * const end_color,
                             const U32 flags)

#vform*

Described under "form"

#vmess*

Described under "mess"

#Embedding, Threads, and Interpreter Cloning

#call_atexit

Add a function fn to the list of functions to be called at global destruction. ptr will be passed as an argument to fn; it can point to a struct so that you can pass anything you want.

Note that under threads, fn may run multiple times. This is because the list is executed each time the current or any descendent thread terminates.

void       call_atexit(      ATEXIT_t fn, void *ptr)
void  Perl_call_atexit(pTHX_ ATEXIT_t fn, void *ptr)

#cv_clone

Clone a CV, making a lexical closure. proto supplies the prototype of the function: its code, pad structure, and other attributes. The prototype is combined with a capture of outer lexicals to which the code refers, which are taken from the currently-executing instance of the immediately surrounding code.

CV *       cv_clone(      CV *proto)
CV *  Perl_cv_clone(pTHX_ CV *proto)

#cv_name

Returns an SV containing the name of the CV, mainly for use in error reporting. The CV may actually be a GV instead, in which case the returned SV holds the GV's name. Anything other than a GV or CV is treated as a string already holding the sub name, but this could change in the future.

An SV may be passed as a second argument. If so, the name will be assigned to it and it will be returned. Otherwise the returned SV will be a new mortal.

If flags has the CV_NAME_NOTQUAL bit set, then the package name will not be included. If the first argument is neither a CV nor a GV, this flag is ignored (subject to change).

SV *       cv_name(      NOCHECK CV *cv, SV *sv, U32 flags)
SV *  Perl_cv_name(pTHX_ NOCHECK CV *cv, SV *sv, U32 flags)

#cv_undef

Clear out all the active components of a CV. This can happen either by an explicit undef &foo, or by the reference count going to zero. In the former case, we keep the CvOUTSIDE pointer, so that any anonymous children can still follow the full lexical scope chain.

void       cv_undef(      CV *cv)
void  Perl_cv_undef(pTHX_ CV *cv)

#find_rundefsv

Returns the global variable $_.

SV *       find_rundefsv()
SV *  Perl_find_rundefsv(pTHX)

#get_op_descs

DEPRECATED! It is planned to remove get_op_descs from a future release of Perl. Do not use it for new code; remove it from existing code.

Return a pointer to the array of all the descriptions of the various OPs Given an opcode from the enum in opcodes.h, PL_op_desc[opcode] returns a pointer to a C language string giving its description.

char **       get_op_descs()
char **  Perl_get_op_descs(pTHX)

#get_op_names

DEPRECATED! It is planned to remove get_op_names from a future release of Perl. Do not use it for new code; remove it from existing code.

Return a pointer to the array of all the names of the various OPs Given an opcode from the enum in opcodes.h, PL_op_name[opcode] returns a pointer to a C language string giving its name.

char **       get_op_names()
char **  Perl_get_op_names(pTHX)

#HAS_SKIP_LOCALE_INIT

Described in perlembed.

#intro_my

"Introduce" my variables to visible status. This is called during parsing at the end of each statement to make lexical variables visible to subsequent statements.

U32       intro_my()
U32  Perl_intro_my(pTHX)

#load_module

#load_module_nocontext

These load the module whose name is pointed to by the string part of name. Note that the actual module name, not its filename, should be given. Eg, "Foo::Bar" instead of "Foo/Bar.pm". ver, if specified and not NULL, provides version semantics similar to use Foo::Bar VERSION. The optional trailing arguments can be used to specify arguments to the module's import() method, similar to use Foo::Bar VERSION LIST; their precise handling depends on the flags. The flags argument is a bitwise-ORed collection of any of PERL_LOADMOD_DENY, PERL_LOADMOD_NOIMPORT, or PERL_LOADMOD_IMPORT_OPS (or 0 for no flags).

If PERL_LOADMOD_NOIMPORT is set, the module is loaded as if with an empty import list, as in use Foo::Bar (); this is the only circumstance in which the trailing optional arguments may be omitted entirely. Otherwise, if PERL_LOADMOD_IMPORT_OPS is set, the trailing arguments must consist of exactly one OP*, containing the op tree that produces the relevant import arguments. Otherwise, the trailing arguments must all be SV* values that will be used as import arguments; and the list must be terminated with (SV*) NULL. If neither PERL_LOADMOD_NOIMPORT nor PERL_LOADMOD_IMPORT_OPS is set, the trailing NULL pointer is needed even if no import arguments are desired. The reference count for each specified SV* argument is decremented. In addition, the name argument is modified.

If PERL_LOADMOD_DENY is set, the module is loaded as if with no rather than use.

load_module and load_module_nocontext have the same apparent signature, but the former hides the fact that it is accessing a thread context parameter. So use the latter when you get a compilation error about pTHX.

void       load_module          (      U32 flags, SV *name,
                                       SV *ver, ...)
void  Perl_load_module          (pTHX_ U32 flags, SV *name,
                                       SV *ver, ...)
void       load_module_nocontext(      U32 flags, SV *name,
                                       SV *ver, ...)
void  Perl_load_module_nocontext(      U32 flags, SV *name,
                                       SV *ver, ...)

#my_exit

A wrapper for the C library exit(3), honoring what "PL_exit_flags" in perlapi say to do.

void       my_exit(      U32 status)
void  Perl_my_exit(pTHX_ U32 status)

#my_failure_exit

Exit the running Perl process with an error.

On non-VMS platforms, this is essentially equivalent to "my_exit", using errno, but forces an en error code of 255 if errno is 0.

On VMS, it takes care to set the appropriate severity bits in the exit status.

void       my_failure_exit()
void  Perl_my_failure_exit(pTHX)

#newPADNAMELIST

NOTE: newPADNAMELIST is experimental and may change or be removed without notice.

Creates a new pad name list. max is the highest index for which space is allocated.

PADNAMELIST *       newPADNAMELIST(size_t max)
PADNAMELIST *  Perl_newPADNAMELIST(size_t max)

#newPADNAMEouter

NOTE: newPADNAMEouter is experimental and may change or be removed without notice.

Constructs and returns a new pad name. Only use this function for names that refer to outer lexicals. (See also "newPADNAMEpvn".) outer is the outer pad name that this one mirrors. The returned pad name has the PADNAMEf_OUTER flag already set.

PADNAME *       newPADNAMEouter(PADNAME *outer)
PADNAME *  Perl_newPADNAMEouter(PADNAME *outer)

#newPADNAMEpvn

NOTE: newPADNAMEpvn is experimental and may change or be removed without notice.

Constructs and returns a new pad name. s must be a UTF-8 string. Do not use this for pad names that point to outer lexicals. See "newPADNAMEouter".

PADNAME *       newPADNAMEpvn(const char *s, STRLEN len)
PADNAME *  Perl_newPADNAMEpvn(const char *s, STRLEN len)

#nothreadhook

Stub that provides thread hook for perl_destruct when there are no threads.

int       nothreadhook()
int  Perl_nothreadhook(pTHX)

#pad_add_anon

Allocates a place in the currently-compiling pad (via "pad_alloc") for an anonymous function that is lexically scoped inside the currently-compiling function. The function func is linked into the pad, and its CvOUTSIDE link to the outer scope is weakened to avoid a reference loop.

One reference count is stolen, so you may need to do SvREFCNT_inc(func).

optype should be an opcode indicating the type of operation that the pad entry is to support. This doesn't affect operational semantics, but is used for debugging.

PADOFFSET       pad_add_anon(      CV *func, I32 optype)
PADOFFSET  Perl_pad_add_anon(pTHX_ CV *func, I32 optype)

#pad_add_name_pv

#pad_add_name_pvn

#pad_add_name_sv

These each allocate a place in the currently-compiling pad for a named lexical variable. They store the name and other metadata in the name part of the pad, and make preparations to manage the variable's lexical scoping. They return the offset of the allocated pad slot.

They differ only in how the input variable's name is specified.

If typestash is non-null, the name is for a typed lexical, and this identifies the type. If ourstash is non-null, it's a lexical reference to a package variable, and this identifies the package. The following flags can be OR'ed together:

padadd_OUR          redundantly specifies if it's a package var
padadd_STATE        variable will retain value persistently
padadd_NO_DUP_CHECK skip check for lexical shadowing
padadd_FIELD        specifies that the lexical is a field for a class

In all forms, the variable name must include the leading sigil.

In pad_add_name_sv, the input name is taken from the SV parameter using "SvPVutf8"().

In pad_add_name_pv, the input name is a NUL-terminated string, which must be encoded in UTF-8.

In pad_add_name_pvn, namelen gives the length of the input name in bytes, which means it may contain embedded NUL characters. Again, it must be encoded in UTF-8.

PADOFFSET       pad_add_name_pv (      const char *name,
                                       const U32 flags,
                                       HV *typestash,
                                       HV *ourstash)
PADOFFSET  Perl_pad_add_name_pv (pTHX_ const char *name,
                                       const U32 flags,
                                       HV *typestash,
                                       HV *ourstash)
PADOFFSET       pad_add_name_pvn(      const char *namepv,
                                       STRLEN namelen, U32 flags,
                                       HV *typestash,
                                       HV *ourstash)
PADOFFSET  Perl_pad_add_name_pvn(pTHX_ const char *namepv,
                                       STRLEN namelen, U32 flags,
                                       HV *typestash,
                                       HV *ourstash)
PADOFFSET       pad_add_name_sv (      SV *name, U32 flags,
                                       HV *typestash,
                                       HV *ourstash)
PADOFFSET  Perl_pad_add_name_sv (pTHX_ SV *name, U32 flags,
                                       HV *typestash,
                                       HV *ourstash)

#pad_alloc

NOTE: pad_alloc is experimental and may change or be removed without notice.

Allocates a place in the currently-compiling pad, returning the offset of the allocated pad slot. No name is initially attached to the pad slot. tmptype is a set of flags indicating the kind of pad entry required, which will be set in the value SV for the allocated pad entry:

SVs_PADMY    named lexical variable ("my", "our", "state")
SVs_PADTMP   unnamed temporary store
SVf_READONLY constant shared between recursion levels

SVf_READONLY has been supported here only since perl 5.20. To work with earlier versions as well, use SVf_READONLY|SVs_PADTMP. SVf_READONLY does not cause the SV in the pad slot to be marked read-only, but simply tells pad_alloc that it will be made read-only (by the caller), or at least should be treated as such.

optype should be an opcode indicating the type of operation that the pad entry is to support. This doesn't affect operational semantics, but is used for debugging.

PADOFFSET       pad_alloc(      I32 optype, U32 tmptype)
PADOFFSET  Perl_pad_alloc(pTHX_ I32 optype, U32 tmptype)

#pad_findmy_pv

#pad_findmy_pvn

#pad_findmy_pvs

#pad_findmy_sv

Given the name of a lexical variable, including its leading sigil, find its position in the currently-compiling pad.

If it is not in the current pad but appears in the pad of any lexically enclosing scope, then a pseudo-entry for it is added in the current pad.

These each return the offset in the current pad, or NOT_IN_PAD if no such lexical is in scope.

The forms differ only in how the variable's name is specified.

In pad_findmy_pvs, the variable name is a C language string literal, enclosed in double quotes.

In plain pad_findmy_pv, the variable name is a C language NUL-terminated string.

In pad_findmy_pvn, len gives the length of the variable name in bytes, so it may contain embedded-NUL characters. The caller must make sure namepv contains at least len bytes.

In pad_findmy_sv, the variable name is taken from the SV parameter using "SvPVutf8"().

flags is reserved and must be zero.

PADOFFSET       pad_findmy_pv (      const char *name, U32 flags)
PADOFFSET  Perl_pad_findmy_pv (pTHX_ const char *name, U32 flags)
PADOFFSET       pad_findmy_pvn(      const char *namepv,
                                     STRLEN namelen, U32 flags)
PADOFFSET  Perl_pad_findmy_pvn(pTHX_ const char *namepv,
                                     STRLEN namelen, U32 flags)
PADOFFSET       pad_findmy_pvs(      "name", U32 flags)
PADOFFSET       pad_findmy_sv (      SV *name, U32 flags)
PADOFFSET  Perl_pad_findmy_sv (pTHX_ SV *name, U32 flags)

#pad_tidy

NOTE: pad_tidy is experimental and may change or be removed without notice.

Tidy up a pad at the end of compilation of the code to which it belongs. Jobs performed here are: remove most stuff from the pads of anonsub prototypes; give it a @_; mark temporaries as such. type indicates the kind of subroutine:

padtidy_SUB        ordinary subroutine
padtidy_SUBCLONE   prototype for lexical closure
padtidy_FORMAT     format

void       pad_tidy(      padtidy_type type)
void  Perl_pad_tidy(pTHX_ padtidy_type type)

#padnamelist_fetch

NOTE: padnamelist_fetch is experimental and may change or be removed without notice.

Fetches the pad name from the given index.

PADNAME *       padnamelist_fetch(PADNAMELIST *pnl, SSize_t key)
PADNAME *  Perl_padnamelist_fetch(PADNAMELIST *pnl, SSize_t key)

#padnamelist_store

NOTE: padnamelist_store is experimental and may change or be removed without notice.

Stores the pad name (which may be null) at the given index, freeing any existing pad name in that slot.

PADNAME **       padnamelist_store(      PADNAMELIST *pnl,
                                         SSize_t key,
                                         PADNAME *val)
PADNAME **  Perl_padnamelist_store(pTHX_ PADNAMELIST *pnl,
                                         SSize_t key,
                                         PADNAME *val)

#perl_alloc

Allocates a new Perl interpreter. See perlembed.

PerlInterpreter *  perl_alloc()

#PERL_ASYNC_CHECK

Described in perlinterp.

void  PERL_ASYNC_CHECK()

#perl_clone

Create and return a new interpreter by cloning the current one.

perl_clone takes these flags as parameters:

CLONEf_COPY_STACKS - is used to, well, copy the stacks also, without it we only clone the data and zero the stacks, with it we copy the stacks and the new perl interpreter is ready to run at the exact same point as the previous one. The pseudo-fork code uses COPY_STACKS while the threads->create doesn't.

CLONEf_KEEP_PTR_TABLE - perl_clone keeps a ptr_table with the pointer of the old variable as a key and the new variable as a value, this allows it to check if something has been cloned and not clone it again, but rather just use the value and increase the refcount. If KEEP_PTR_TABLE is not set then perl_clone will kill the ptr_table using the function ptr_table_free(PL_ptr_table); PL_ptr_table = NULL;. A reason to keep it around is if you want to dup some of your own variables which are outside the graph that perl scans.

CLONEf_CLONE_HOST - This is a win32 thing, it is ignored on unix, it tells perl's win32host code (which is c++) to clone itself, this is needed on win32 if you want to run two threads at the same time, if you just want to do some stuff in a separate perl interpreter and then throw it away and return to the original one, you don't need to do anything.

PerlInterpreter *  perl_clone(PerlInterpreter *proto_perl,
                              UV flags)

#perl_construct

Initializes a new Perl interpreter. See perlembed.

void  perl_construct(PerlInterpreter *my_perl)

#perl_destruct

Shuts down a Perl interpreter. See perlembed for a tutorial.

my_perl points to the Perl interpreter. It must have been previously created through the use of "perl_alloc" and "perl_construct". It may have been initialised through "perl_parse", and may have been used through "perl_run" and other means. This function should be called for any Perl interpreter that has been constructed with "perl_construct", even if subsequent operations on it failed, for example if "perl_parse" returned a non-zero value.

If the interpreter's PL_exit_flags word has the PERL_EXIT_DESTRUCT_END flag set, then this function will execute code in END blocks before performing the rest of destruction. If it is desired to make any use of the interpreter between "perl_parse" and "perl_destruct" other than just calling "perl_run", then this flag should be set early on. This matters if "perl_run" will not be called, or if anything else will be done in addition to calling "perl_run".

Returns a value be a suitable value to pass to the C library function exit (or to return from main), to serve as an exit code indicating the nature of the way the interpreter terminated. This takes into account any failure of "perl_parse" and any early exit from "perl_run". The exit code is of the type required by the host operating system, so because of differing exit code conventions it is not portable to interpret specific numeric values as having specific meanings.

int  perl_destruct(PerlInterpreter *my_perl)

#perl_free

Releases a Perl interpreter. See perlembed.

void  perl_free(PerlInterpreter *my_perl)

#PERL_GET_CONTEXT

Described in perlguts.

PerlInterpreter*  PERL_GET_CONTEXT

#perl_parse

Tells a Perl interpreter to parse a Perl script. This performs most of the initialisation of a Perl interpreter. See perlembed for a tutorial.

my_perl points to the Perl interpreter that is to parse the script. It must have been previously created through the use of "perl_alloc" and "perl_construct". xsinit points to a callback function that will be called to set up the ability for this Perl interpreter to load XS extensions, or may be null to perform no such setup.

argc and argv supply a set of command-line arguments to the Perl interpreter, as would normally be passed to the main function of a C program. argv[argc] must be null. These arguments are where the script to parse is specified, either by naming a script file or by providing a script in a -e option. If $0 will be written to in the Perl interpreter, then the argument strings must be in writable memory, and so mustn't just be string constants.

env specifies a set of environment variables that will be used by this Perl interpreter. If non-null, it must point to a null-terminated array of environment strings. If null, the Perl interpreter will use the environment supplied by the environ global variable.

This function initialises the interpreter, and parses and compiles the script specified by the command-line arguments. This includes executing code in BEGIN, UNITCHECK, and CHECK blocks. It does not execute INIT blocks or the main program.

Returns an integer of slightly tricky interpretation. The correct use of the return value is as a truth value indicating whether there was a failure in initialisation. If zero is returned, this indicates that initialisation was successful, and it is safe to proceed to call "perl_run" and make other use of it. If a non-zero value is returned, this indicates some problem that means the interpreter wants to terminate. The interpreter should not be just abandoned upon such failure; the caller should proceed to shut the interpreter down cleanly with "perl_destruct" and free it with "perl_free".

For historical reasons, the non-zero return value also attempts to be a suitable value to pass to the C library function exit (or to return from main), to serve as an exit code indicating the nature of the way initialisation terminated. However, this isn't portable, due to differing exit code conventions. An attempt is made to return an exit code of the type required by the host operating system, but because it is constrained to be non-zero, it is not necessarily possible to indicate every type of exit. It is only reliable on Unix, where a zero exit code can be augmented with a set bit that will be ignored. In any case, this function is not the correct place to acquire an exit code: one should get that from "perl_destruct".

int  perl_parse(PerlInterpreter *my_perl, XSINIT_t xsinit,
                int argc, char **argv, char **env)

#perl_run

Tells a Perl interpreter to run its main program. See perlembed for a tutorial.

my_perl points to the Perl interpreter. It must have been previously created through the use of "perl_alloc" and "perl_construct", and initialised through "perl_parse". This function should not be called if "perl_parse" returned a non-zero value, indicating a failure in initialisation or compilation.

This function executes code in INIT blocks, and then executes the main program. The code to be executed is that established by the prior call to "perl_parse". If the interpreter's PL_exit_flags word does not have the PERL_EXIT_DESTRUCT_END flag set, then this function will also execute code in END blocks. If it is desired to make any further use of the interpreter after calling this function, then END blocks should be postponed to "perl_destruct" time by setting that flag.

Returns an integer of slightly tricky interpretation. The correct use of the return value is as a truth value indicating whether the program terminated non-locally. If zero is returned, this indicates that the program ran to completion, and it is safe to make other use of the interpreter (provided that the PERL_EXIT_DESTRUCT_END flag was set as described above). If a non-zero value is returned, this indicates that the interpreter wants to terminate early. The interpreter should not be just abandoned because of this desire to terminate; the caller should proceed to shut the interpreter down cleanly with "perl_destruct" and free it with "perl_free".

For historical reasons, the non-zero return value also attempts to be a suitable value to pass to the C library function exit (or to return from main), to serve as an exit code indicating the nature of the way the program terminated. However, this isn't portable, due to differing exit code conventions. An attempt is made to return an exit code of the type required by the host operating system, but because it is constrained to be non-zero, it is not necessarily possible to indicate every type of exit. It is only reliable on Unix, where a zero exit code can be augmented with a set bit that will be ignored. In any case, this function is not the correct place to acquire an exit code: one should get that from "perl_destruct".

int  perl_run(PerlInterpreter *my_perl)

#PERL_SET_CONTEXT

Described in perlguts.

void  PERL_SET_CONTEXT(PerlInterpreter* i)

#PERL_SYS_INIT

#PERL_SYS_INIT3

These provide system-specific tune up of the C runtime environment necessary to run Perl interpreters. Only one should be used, and it should be called only once, before creating any Perl interpreters.

They differ in that PERL_SYS_INIT3 also initializes env.

void  PERL_SYS_INIT (int *argc, char*** argv)
void  PERL_SYS_INIT3(int *argc, char*** argv, char*** env)

#PERL_SYS_TERM

Provides system-specific clean up of the C runtime environment after running Perl interpreters. This should be called only once, after freeing any remaining Perl interpreters.

void  PERL_SYS_TERM()

#PerlInterpreter

Described in perlembed.

#PL_exit_flags

Contains flags controlling perl's behaviour on exit():

• PERL_EXIT_DESTRUCT_END

  If set, END blocks are executed when the interpreter is destroyed. This is normally set by perl itself after the interpreter is constructed.

• PERL_EXIT_ABORT

  Call abort() on exit. This is used internally by perl itself to abort if exit is called while processing exit.

• PERL_EXIT_WARN

  Warn on exit.

• PERL_EXIT_EXPECTED

  Set by the "exit" in perlfunc operator.

U8  PL_exit_flags

#PL_origalen

Described in perlembed.

#PL_perl_destruct_level

This value may be set when embedding for full cleanup.

Possible values:

• 0 - none

• 1 - full

• 2 or greater - full with checks.

If $ENV{PERL_DESTRUCT_LEVEL} is set to an integer greater than the value of PL_perl_destruct_level its value is used instead.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

signed char  PL_perl_destruct_level

#ptr_table_fetch

Look for sv in the pointer-mapping table tbl, returning its value, or NULL if not found.

void *       ptr_table_fetch(      PTR_TBL_t * const tbl,
                                   const void * const sv)
void *  Perl_ptr_table_fetch(pTHX_ PTR_TBL_t * const tbl,
                                   const void * const sv)

#ptr_table_free

Clear and free a ptr table

void       ptr_table_free(      PTR_TBL_t * const tbl)
void  Perl_ptr_table_free(pTHX_ PTR_TBL_t * const tbl)

#ptr_table_new

Create a new pointer-mapping table

PTR_TBL_t *       ptr_table_new()
PTR_TBL_t *  Perl_ptr_table_new(pTHX)

#ptr_table_split

Double the hash bucket size of an existing ptr table

void       ptr_table_split(      PTR_TBL_t * const tbl)
void  Perl_ptr_table_split(pTHX_ PTR_TBL_t * const tbl)

#ptr_table_store

Add a new entry to a pointer-mapping table tbl. In hash terms, oldsv is the key; Cnewsv> is the value.

The names "old" and "new" are specific to the core's typical use of ptr_tables in thread cloning.

void       ptr_table_store(      PTR_TBL_t * const tbl,
                                 const void * const oldsv,
                                 void * const newsv)
void  Perl_ptr_table_store(pTHX_ PTR_TBL_t * const tbl,
                                 const void * const oldsv,
                                 void * const newsv)

#require_pv

Tells Perl to require the file named by the string argument. It is analogous to the Perl code eval "require '$file'". It's even implemented that way; consider using load_module instead.

NOTE: the perl_require_pv() form is deprecated.

void       require_pv(      const char *pv)
void  Perl_require_pv(pTHX_ const char *pv)

#vload_module

Like "load_module" but the arguments are an encapsulated argument list.

void       vload_module(      U32 flags, SV *name, SV *ver,
                              va_list *args)
void  Perl_vload_module(pTHX_ U32 flags, SV *name, SV *ver,
                              va_list *args)

#Errno

#sv_string_from_errnum

Generates the message string describing an OS error and returns it as an SV. errnum must be a value that errno could take, identifying the type of error.

If tgtsv is non-null then the string will be written into that SV (overwriting existing content) and it will be returned. If tgtsv is a null pointer then the string will be written into a new mortal SV which will be returned.

The message will be taken from whatever locale would be used by $!, and will be encoded in the SV in whatever manner would be used by $!. The details of this process are subject to future change. Currently, the message is taken from the C locale by default (usually producing an English message), and from the currently selected locale when in the scope of the use locale pragma. A heuristic attempt is made to decode the message from the locale's character encoding, but it will only be decoded as either UTF-8 or ISO-8859-1. It is always correctly decoded in a UTF-8 locale, usually in an ISO-8859-1 locale, and never in any other locale.

The SV is always returned containing an actual string, and with no other OK bits set. Unlike $!, a message is even yielded for errnum zero (meaning success), and if no useful message is available then a useless string (currently empty) is returned.

SV *       sv_string_from_errnum(      int errnum, SV *tgtsv)
SV *  Perl_sv_string_from_errnum(pTHX_ int errnum, SV *tgtsv)

#Exception Handling (simple) Macros

#dXCPT

Set up necessary local variables for exception handling. See "Exception Handling" in perlguts.

dXCPT;

#JMPENV_JUMP

#JMPENV_PUSH

#PL_restartop

Described in perlinterp.

void  JMPENV_JUMP (int v)
void  JMPENV_PUSH (int v)
OP *  PL_restartop

#XCPT_CATCH

Introduces a catch block. See "Exception Handling" in perlguts.

#XCPT_RETHROW

Rethrows a previously caught exception. See "Exception Handling" in perlguts.

XCPT_RETHROW;

#XCPT_TRY_END

Ends a try block. See "Exception Handling" in perlguts.

#XCPT_TRY_START

Starts a try block. See "Exception Handling" in perlguts.

#Filesystem configuration values

Also see "List of capability HAS_foo symbols".

#DIRNAMLEN

This symbol, if defined, indicates to the C program that the length of directory entry names is provided by a d_namlen field. Otherwise you need to do strlen() on the d_name field.

#DOSUID

This symbol, if defined, indicates that the C program should check the script that it is executing for setuid/setgid bits, and attempt to emulate setuid/setgid on systems that have disabled setuid #! scripts because the kernel can't do it securely. It is up to the package designer to make sure that this emulation is done securely. Among other things, it should do an fstat on the script it just opened to make sure it really is a setuid/setgid script, it should make sure the arguments passed correspond exactly to the argument on the #! line, and it should not trust any subprocesses to which it must pass the filename rather than the file descriptor of the script to be executed.

#EOF_NONBLOCK

This symbol, if defined, indicates to the C program that a read() on a non-blocking file descriptor will return 0 on EOF, and not the value held in RD_NODATA (-1 usually, in that case!).

#FCNTL_CAN_LOCK

This symbol, if defined, indicates that fcntl() can be used for file locking. Normally on Unix systems this is defined. It may be undefined on VMS.

#FFLUSH_ALL

This symbol, if defined, tells that to flush all pending stdio output one must loop through all the stdio file handles stored in an array and fflush them. Note that if fflushNULL is defined, fflushall will not even be probed for and will be left undefined.

#FFLUSH_NULL

This symbol, if defined, tells that fflush(NULL) correctly flushes all pending stdio output without side effects. In particular, on some platforms calling fflush(NULL) *still* corrupts STDIN if it is a pipe.

#FILE_base

This macro is used to access the _base field (or equivalent) of the FILE structure pointed to by its argument. This macro will always be defined if USE_STDIO_BASE is defined.

void *  FILE_base(FILE * f)

#FILE_bufsiz

This macro is used to determine the number of bytes in the I/O buffer pointed to by _base field (or equivalent) of the FILE structure pointed to its argument. This macro will always be defined if USE_STDIO_BASE is defined.

Size_t  FILE_bufsiz(FILE *f)

#FILE_cnt

This macro is used to access the _cnt field (or equivalent) of the FILE structure pointed to by its argument. This macro will always be defined if USE_STDIO_PTR is defined.

Size_t  FILE_cnt(FILE * f)

#FILE_ptr

This macro is used to access the _ptr field (or equivalent) of the FILE structure pointed to by its argument. This macro will always be defined if USE_STDIO_PTR is defined.

void *  FILE_ptr(FILE * f)

#FLEXFILENAMES

This symbol, if defined, indicates that the system supports filenames longer than 14 characters.

#HAS_DIR_DD_FD

This symbol, if defined, indicates that the DIR* dirstream structure contains a member variable named dd_fd.

#HAS_DUP2

This symbol, if defined, indicates that the dup2 routine is available to duplicate file descriptors.

#HAS_DUP3

This symbol, if defined, indicates that the dup3 routine is available to duplicate file descriptors.

#HAS_FAST_STDIO

This symbol, if defined, indicates that the "fast stdio" is available to manipulate the stdio buffers directly.

#HAS_FCHDIR

This symbol, if defined, indicates that the fchdir routine is available to change directory using a file descriptor.

#HAS_FCNTL

This symbol, if defined, indicates to the C program that the fcntl() function exists.

#HAS_FDCLOSE

This symbol, if defined, indicates that the fdclose routine is available to free a FILE structure without closing the underlying file descriptor. This function appeared in FreeBSD 10.2.

#HAS_FDOPENDIR

This symbol, if defined, indicates that the fdopendir routine is available to open a directory descriptor.

#HAS_FPATHCONF

This symbol, if defined, indicates that pathconf() is available to determine file-system related limits and options associated with a given open file descriptor.

#HAS_FPOS64_T

This symbol will be defined if the C compiler supports fpos64_t.

#HAS_FSTATFS

This symbol, if defined, indicates that the fstatfs routine is available to stat filesystems by file descriptors.

#HAS_FSTATVFS

This symbol, if defined, indicates that the fstatvfs routine is available to stat filesystems by file descriptors.

#HAS_GETFSSTAT

This symbol, if defined, indicates that the getfsstat routine is available to stat filesystems in bulk.

#HAS_GETMNT

This symbol, if defined, indicates that the getmnt routine is available to get filesystem mount info by filename.

#HAS_GETMNTENT

This symbol, if defined, indicates that the getmntent routine is available to iterate through mounted file systems to get their info.

#HAS_HASMNTOPT

This symbol, if defined, indicates that the hasmntopt routine is available to query the mount options of file systems.

#HAS_LSEEK_PROTO

This symbol, if defined, indicates that the system provides a prototype for the lseek() function. Otherwise, it is up to the program to supply one. A good guess is

extern off_t lseek(int, off_t, int);

#HAS_MKDIR

This symbol, if defined, indicates that the mkdir routine is available to create directories. Otherwise you should fork off a new process to exec /bin/mkdir.

#HAS_OFF64_T

This symbol will be defined if the C compiler supports off64_t.

#HAS_OPENAT

This symbol is defined if the openat() routine is available.

#HAS_OPEN3

This manifest constant lets the C program know that the three argument form of open(2) is available.

#HAS_POLL

This symbol, if defined, indicates that the poll routine is available to poll active file descriptors. Please check I_POLL and I_SYS_POLL to know which header should be included as well.

#HAS_READDIR

This symbol, if defined, indicates that the readdir routine is available to read directory entries. You may have to include dirent.h. See "I_DIRENT".

#HAS_READDIR64_R

This symbol, if defined, indicates that the readdir64_r routine is available to readdir64 re-entrantly.

#HAS_REWINDDIR

This symbol, if defined, indicates that the rewinddir routine is available. You may have to include dirent.h. See "I_DIRENT".

#HAS_RMDIR

This symbol, if defined, indicates that the rmdir routine is available to remove directories. Otherwise you should fork off a new process to exec /bin/rmdir.

#HAS_SEEKDIR

This symbol, if defined, indicates that the seekdir routine is available. You may have to include dirent.h. See "I_DIRENT".

#HAS_SELECT

This symbol, if defined, indicates that the select routine is available to select active file descriptors. If the timeout field is used, sys/time.h may need to be included.

#HAS_SETVBUF

This symbol, if defined, indicates that the setvbuf routine is available to change buffering on an open stdio stream. to a line-buffered mode.

#HAS_STDIO_STREAM_ARRAY

This symbol, if defined, tells that there is an array holding the stdio streams.

#HAS_STRUCT_FS_DATA

This symbol, if defined, indicates that the struct fs_data to do statfs() is supported.

#HAS_STRUCT_STATFS

This symbol, if defined, indicates that the struct statfs to do statfs() is supported.

#HAS_STRUCT_STATFS_F_FLAGS

This symbol, if defined, indicates that the struct statfs does have the f_flags member containing the mount flags of the filesystem containing the file. This kind of struct statfs is coming from sys/mount.h (BSD 4.3), not from sys/statfs.h (SYSV). Older BSDs (like Ultrix) do not have statfs() and struct statfs, they have ustat() and getmnt() with struct ustat and struct fs_data.

#HAS_TELLDIR

This symbol, if defined, indicates that the telldir routine is available. You may have to include dirent.h. See "I_DIRENT".

#HAS_USTAT

This symbol, if defined, indicates that the ustat system call is available to query file system statistics by dev_t.

#I_FCNTL

This manifest constant tells the C program to include fcntl.h.

#ifdef I_FCNTL
    #include <fcntl.h>
#endif

#I_SYS_DIR

This symbol, if defined, indicates to the C program that it should include sys/dir.h.

#ifdef I_SYS_DIR
    #include <sys_dir.h>
#endif

#I_SYS_FILE

This symbol, if defined, indicates to the C program that it should include sys/file.h to get definition of R_OK and friends.

#ifdef I_SYS_FILE
    #include <sys_file.h>
#endif

#I_SYS_NDIR

This symbol, if defined, indicates to the C program that it should include sys/ndir.h.

#ifdef I_SYS_NDIR
    #include <sys_ndir.h>
#endif

#I_SYS_STATFS

This symbol, if defined, indicates that sys/statfs.h exists.

#ifdef I_SYS_STATFS
    #include <sys_statfs.h>
#endif

#LSEEKSIZE

This symbol holds the number of bytes used by the Off_t.

#RD_NODATA

This symbol holds the return code from read() when no data is present on the non-blocking file descriptor. Be careful! If EOF_NONBLOCK is not defined, then you can't distinguish between no data and EOF by issuing a read(). You'll have to find another way to tell for sure!

#READDIR64_R_PROTO

This symbol encodes the prototype of readdir64_r. It is zero if d_readdir64_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_readdir64_r is defined.

#ST_INO_SIGN

This symbol holds the signedness of struct stat's st_ino. 1 for unsigned, -1 for signed.

#ST_INO_SIZE

This variable contains the size of struct stat's st_ino in bytes.

#STDCHAR

This symbol is defined to be the type of char used in stdio.h. It has the values "unsigned char" or "char".

#STDIO_CNT_LVALUE

This symbol is defined if the FILE_cnt macro can be used as an lvalue.

#STDIO_PTR_LVAL_NOCHANGE_CNT

This symbol is defined if using the FILE_ptr macro as an lvalue to increase the pointer by n leaves File_cnt(fp) unchanged.

#STDIO_PTR_LVAL_SETS_CNT

This symbol is defined if using the FILE_ptr macro as an lvalue to increase the pointer by n has the side effect of decreasing the value of File_cnt(fp) by n.

#STDIO_PTR_LVALUE

This symbol is defined if the FILE_ptr macro can be used as an lvalue.

#STDIO_STREAM_ARRAY

This symbol tells the name of the array holding the stdio streams. Usual values include _iob, __iob, and __sF.

#VAL_EAGAIN

This symbol holds the errno error code set by read() when no data was present on the non-blocking file descriptor.

#VAL_O_NONBLOCK

This symbol is to be used during open() or fcntl(F_SETFL) to turn on non-blocking I/O for the file descriptor. Note that there is no way back, i.e. you cannot turn it blocking again this way. If you wish to alternatively switch between blocking and non-blocking, use the ioctl(FIOSNBIO) call instead, but that is not supported by all devices.

#VOID_CLOSEDIR

This symbol, if defined, indicates that the closedir() routine does not return a value.

#Floating point

Also "List of capability HAS_foo symbols" lists capabilities that arent in this section. For example HAS_ASINH, for the hyperbolic sine function.

#CASTFLAGS

This symbol contains flags that say what difficulties the compiler has casting odd floating values to unsigned long:

0 = ok
1 = couldn't cast < 0
2 = couldn't cast >= 0x80000000
4 = couldn't cast in argument expression list

#CASTNEGFLOAT

This symbol is defined if the C compiler can cast negative numbers to unsigned longs, ints and shorts.

#DOUBLE_HAS_INF

This symbol, if defined, indicates that the double has the infinity.

#DOUBLE_HAS_NAN

This symbol, if defined, indicates that the double has the not-a-number.

#DOUBLE_HAS_NEGATIVE_ZERO

This symbol, if defined, indicates that the double has the negative_zero.

#DOUBLE_HAS_SUBNORMALS

This symbol, if defined, indicates that the double has the subnormals (denormals).

#DOUBLE_STYLE_CRAY

This symbol, if defined, indicates that the double is the 64-bit CRAY mainframe format.

#DOUBLE_STYLE_IBM

This symbol, if defined, indicates that the double is the 64-bit IBM mainframe format.

#DOUBLE_STYLE_IEEE

This symbol, if defined, indicates that the double is the 64-bit IEEE 754.

#DOUBLE_STYLE_VAX

This symbol, if defined, indicates that the double is the 64-bit VAX format D or G.

#DOUBLEINFBYTES

This symbol, if defined, is a comma-separated list of hexadecimal bytes for the double precision infinity.

#DOUBLEKIND

DOUBLEKIND will be one of DOUBLE_IS_IEEE_754_32_BIT_LITTLE_ENDIAN DOUBLE_IS_IEEE_754_32_BIT_BIG_ENDIAN DOUBLE_IS_IEEE_754_64_BIT_LITTLE_ENDIAN DOUBLE_IS_IEEE_754_64_BIT_BIG_ENDIAN DOUBLE_IS_IEEE_754_128_BIT_LITTLE_ENDIAN DOUBLE_IS_IEEE_754_128_BIT_BIG_ENDIAN DOUBLE_IS_IEEE_754_64_BIT_MIXED_ENDIAN_LE_BE DOUBLE_IS_IEEE_754_64_BIT_MIXED_ENDIAN_BE_LE DOUBLE_IS_VAX_F_FLOAT DOUBLE_IS_VAX_D_FLOAT DOUBLE_IS_VAX_G_FLOAT DOUBLE_IS_IBM_SINGLE_32_BIT DOUBLE_IS_IBM_DOUBLE_64_BIT DOUBLE_IS_CRAY_SINGLE_64_BIT DOUBLE_IS_UNKNOWN_FORMAT

#DOUBLEMANTBITS

This symbol, if defined, tells how many mantissa bits there are in double precision floating point format. Note that this is usually DBL_MANT_DIG minus one, since with the standard IEEE 754 formats DBL_MANT_DIG includes the implicit bit, which doesn't really exist.

#DOUBLENANBYTES

This symbol, if defined, is a comma-separated list of hexadecimal bytes (0xHH) for the double precision not-a-number.

#DOUBLESIZE

This symbol contains the size of a double, so that the C preprocessor can make decisions based on it.

#Gconvert

This preprocessor macro is defined to convert a floating point number to a string without a trailing decimal point. This emulates the behavior of sprintf("%g"), but is sometimes much more efficient. If gconvert() is not available, but gcvt() drops the trailing decimal point, then gcvt() is used. If all else fails, a macro using sprintf("%g") is used. Arguments for the Gconvert macro are: value, number of digits, whether trailing zeros should be retained, and the output buffer. The usual values are:

d_Gconvert='gconvert((x),(n),(t),(b))'
d_Gconvert='gcvt((x),(n),(b))'
d_Gconvert='sprintf((b),"%.*g",(n),(x))'

The last two assume trailing zeros should not be kept.

char *  Gconvert(double x, Size_t n, bool t, char * b)

#HAS_ATOLF

This symbol, if defined, indicates that the atolf routine is available to convert strings into long doubles.

#HAS_CLASS

This symbol, if defined, indicates that the class routine is available to classify doubles. Available for example in AIX. The returned values are defined in float.h and are:

FP_PLUS_NORM    Positive normalized, nonzero
FP_MINUS_NORM   Negative normalized, nonzero
FP_PLUS_DENORM  Positive denormalized, nonzero
FP_MINUS_DENORM Negative denormalized, nonzero
FP_PLUS_ZERO    +0.0
FP_MINUS_ZERO   -0.0
FP_PLUS_INF     +INF
FP_MINUS_INF    -INF
FP_NANS         Signaling Not a Number (NaNS)
FP_NANQ         Quiet Not a Number (NaNQ)

#HAS_FINITE

This symbol, if defined, indicates that the finite routine is available to check whether a double is finite (non-infinity non-NaN).

#HAS_FINITEL

This symbol, if defined, indicates that the finitel routine is available to check whether a long double is finite (non-infinity non-NaN).

#HAS_FP_CLASS

This symbol, if defined, indicates that the fp_class routine is available to classify doubles. Available for example in Digital UNIX. The returned values are defined in math.h and are:

FP_SNAN           Signaling NaN (Not-a-Number)
FP_QNAN           Quiet NaN (Not-a-Number)
FP_POS_INF        +infinity
FP_NEG_INF        -infinity
FP_POS_NORM       Positive normalized
FP_NEG_NORM       Negative normalized
FP_POS_DENORM     Positive denormalized
FP_NEG_DENORM     Negative denormalized
FP_POS_ZERO       +0.0 (positive zero)
FP_NEG_ZERO       -0.0 (negative zero)

#HAS_FP_CLASSIFY

This symbol, if defined, indicates that the fp_classify routine is available to classify doubles. The values are defined in math.h

FP_NORMAL     Normalized
FP_ZERO       Zero
FP_INFINITE   Infinity
FP_SUBNORMAL  Denormalized
FP_NAN        NaN

#HAS_FP_CLASSL

This symbol, if defined, indicates that the fp_classl routine is available to classify long doubles. Available for example in Digital UNIX. See for possible values HAS_FP_CLASS.

#HAS_FPCLASS

This symbol, if defined, indicates that the fpclass routine is available to classify doubles. Available for example in Solaris/SVR4. The returned values are defined in ieeefp.h and are:

FP_SNAN         signaling NaN
FP_QNAN         quiet NaN
FP_NINF         negative infinity
FP_PINF         positive infinity
FP_NDENORM      negative denormalized non-zero
FP_PDENORM      positive denormalized non-zero
FP_NZERO        negative zero
FP_PZERO        positive zero
FP_NNORM        negative normalized non-zero
FP_PNORM        positive normalized non-zero

#HAS_FPCLASSIFY

This symbol, if defined, indicates that the fpclassify routine is available to classify doubles. Available for example in HP-UX. The returned values are defined in math.h and are

FP_NORMAL     Normalized
FP_ZERO       Zero
FP_INFINITE   Infinity
FP_SUBNORMAL  Denormalized
FP_NAN        NaN

#HAS_FPCLASSL

This symbol, if defined, indicates that the fpclassl routine is available to classify long doubles. Available for example in IRIX. The returned values are defined in ieeefp.h and are:

FP_SNAN         signaling NaN
FP_QNAN         quiet NaN
FP_NINF         negative infinity
FP_PINF         positive infinity
FP_NDENORM      negative denormalized non-zero
FP_PDENORM      positive denormalized non-zero
FP_NZERO        negative zero
FP_PZERO        positive zero
FP_NNORM        negative normalized non-zero
FP_PNORM        positive normalized non-zero

#HAS_FPGETROUND

This symbol, if defined, indicates that the fpgetround routine is available to get the floating point rounding mode.

#HAS_FREXPL

This symbol, if defined, indicates that the frexpl routine is available to break a long double floating-point number into a normalized fraction and an integral power of 2.

#HAS_ILOGB

This symbol, if defined, indicates that the ilogb routine is available to get integer exponent of a floating-point value.

#HAS_ISFINITE

This symbol, if defined, indicates that the isfinite routine is available to check whether a double is finite (non-infinity non-NaN).

#HAS_ISFINITEL

This symbol, if defined, indicates that the isfinitel routine is available to check whether a long double is finite. (non-infinity non-NaN).

#HAS_ISINF

This symbol, if defined, indicates that the isinf routine is available to check whether a double is an infinity.

#HAS_ISINFL

This symbol, if defined, indicates that the isinfl routine is available to check whether a long double is an infinity.

#HAS_ISNAN

This symbol, if defined, indicates that the isnan routine is available to check whether a double is a NaN.

#HAS_ISNANL

This symbol, if defined, indicates that the isnanl routine is available to check whether a long double is a NaN.

#HAS_ISNORMAL

This symbol, if defined, indicates that the isnormal routine is available to check whether a double is normal (non-zero normalized).

#HAS_J0

This symbol, if defined, indicates to the C program that the j0() function is available for Bessel functions of the first kind of the order zero, for doubles.

#HAS_J0L

This symbol, if defined, indicates to the C program that the j0l() function is available for Bessel functions of the first kind of the order zero, for long doubles.

#HAS_LDBL_DIG

This symbol, if defined, indicates that this system's float.h or limits.h defines the symbol LDBL_DIG, which is the number of significant digits in a long double precision number. Unlike for DBL_DIG, there's no good guess for LDBL_DIG if it is undefined.

#HAS_LDEXPL

This symbol, if defined, indicates that the ldexpl routine is available to shift a long double floating-point number by an integral power of 2.

#HAS_LLRINT

This symbol, if defined, indicates that the llrint routine is available to return the long long value closest to a double (according to the current rounding mode).

#HAS_LLRINTL

This symbol, if defined, indicates that the llrintl routine is available to return the long long value closest to a long double (according to the current rounding mode).

#HAS_LLROUNDL

This symbol, if defined, indicates that the llroundl routine is available to return the nearest long long value away from zero of the long double argument value.

#HAS_LONG_DOUBLE

This symbol will be defined if the C compiler supports long doubles.

#HAS_LRINT

This symbol, if defined, indicates that the lrint routine is available to return the integral value closest to a double (according to the current rounding mode).

#HAS_LRINTL

This symbol, if defined, indicates that the lrintl routine is available to return the integral value closest to a long double (according to the current rounding mode).

#HAS_LROUNDL

This symbol, if defined, indicates that the lroundl routine is available to return the nearest integral value away from zero of the long double argument value.

#HAS_MODFL

This symbol, if defined, indicates that the modfl routine is available to split a long double x into a fractional part f and an integer part i such that |f| < 1.0 and (f + i) = x.

#HAS_NAN

This symbol, if defined, indicates that the nan routine is available to generate NaN.

#HAS_NEXTTOWARD

This symbol, if defined, indicates that the nexttoward routine is available to return the next machine representable long double from x in direction y.

#HAS_REMAINDER

This symbol, if defined, indicates that the remainder routine is available to return the floating-point remainder.

#HAS_SCALBN

This symbol, if defined, indicates that the scalbn routine is available to multiply floating-point number by integral power of radix.

#HAS_SIGNBIT

This symbol, if defined, indicates that the signbit routine is available to check if the given number has the sign bit set. This should include correct testing of -0.0. This will only be set if the signbit() routine is safe to use with the NV type used internally in perl. Users should call Perl_signbit(), which will be #defined to the system's signbit() function or macro if this symbol is defined.

#HAS_SQRTL

This symbol, if defined, indicates that the sqrtl routine is available to do long double square roots.

#HAS_STRTOD_L

This symbol, if defined, indicates that the strtod_l routine is available to convert strings to long doubles.

#HAS_STRTOLD

This symbol, if defined, indicates that the strtold routine is available to convert strings to long doubles.

#HAS_STRTOLD_L

This symbol, if defined, indicates that the strtold_l routine is available to convert strings to long doubles.

#HAS_TRUNC

This symbol, if defined, indicates that the trunc routine is available to round doubles towards zero.

#HAS_UNORDERED

This symbol, if defined, indicates that the unordered routine is available to check whether two doubles are unordered (effectively: whether either of them is NaN)

#I_FENV

This symbol, if defined, indicates to the C program that it should include fenv.h to get the floating point environment definitions.

#ifdef I_FENV
    #include <fenv.h>
#endif

#I_QUADMATH

This symbol, if defined, indicates that quadmath.h exists and should be included.

#ifdef I_QUADMATH
    #include <quadmath.h>
#endif

#LONG_DOUBLE_STYLE_IEEE

This symbol, if defined, indicates that the long double is any of the IEEE 754 style long doubles: LONG_DOUBLE_STYLE_IEEE_STD, LONG_DOUBLE_STYLE_IEEE_EXTENDED, LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE.

#LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE

This symbol, if defined, indicates that the long double is the 128-bit double-double.

#LONG_DOUBLE_STYLE_IEEE_EXTENDED

This symbol, if defined, indicates that the long double is the 80-bit IEEE 754. Note that despite the 'extended' this is less than the 'std', since this is an extension of the double precision.

#LONG_DOUBLE_STYLE_IEEE_STD

This symbol, if defined, indicates that the long double is the 128-bit IEEE 754.

#LONG_DOUBLE_STYLE_VAX

This symbol, if defined, indicates that the long double is the 128-bit VAX format H.

#LONG_DOUBLEKIND

LONG_DOUBLEKIND will be one of LONG_DOUBLE_IS_DOUBLE LONG_DOUBLE_IS_IEEE_754_128_BIT_LITTLE_ENDIAN LONG_DOUBLE_IS_IEEE_754_128_BIT_BIG_ENDIAN LONG_DOUBLE_IS_X86_80_BIT_LITTLE_ENDIAN LONG_DOUBLE_IS_X86_80_BIT_BIG_ENDIAN LONG_DOUBLE_IS_DOUBLEDOUBLE_128_BIT_LE_LE LONG_DOUBLE_IS_DOUBLEDOUBLE_128_BIT_BE_BE LONG_DOUBLE_IS_DOUBLEDOUBLE_128_BIT_LE_BE LONG_DOUBLE_IS_DOUBLEDOUBLE_128_BIT_BE_LE LONG_DOUBLE_IS_DOUBLEDOUBLE_128_BIT_LITTLE_ENDIAN LONG_DOUBLE_IS_DOUBLEDOUBLE_128_BIT_BIG_ENDIAN LONG_DOUBLE_IS_VAX_H_FLOAT LONG_DOUBLE_IS_UNKNOWN_FORMAT It is only defined if the system supports long doubles.

#LONG_DOUBLESIZE

This symbol contains the size of a long double, so that the C preprocessor can make decisions based on it. It is only defined if the system supports long doubles. Note that this is sizeof(long double), which may include unused bytes.

#LONGDBLINFBYTES

This symbol, if defined, is a comma-separated list of hexadecimal bytes for the long double precision infinity.

#LONGDBLMANTBITS

This symbol, if defined, tells how many mantissa bits there are in long double precision floating point format. Note that this can be LDBL_MANT_DIG minus one, since LDBL_MANT_DIG can include the IEEE 754 implicit bit. The common x86-style 80-bit long double does not have an implicit bit.

#LONGDBLNANBYTES

This symbol, if defined, is a comma-separated list of hexadecimal bytes (0xHH) for the long double precision not-a-number.

#NV

Described in perlguts.

#NV_OVERFLOWS_INTEGERS_AT

This symbol gives the largest integer value that NVs can hold. This value + 1.0 cannot be stored accurately. It is expressed as constant floating point expression to reduce the chance of decimal/binary conversion issues. If it can not be determined, the value 0 is given.

#NV_PRESERVES_UV

This symbol, if defined, indicates that a variable of type NVTYPE can preserve all the bits of a variable of type UVTYPE.

#NV_PRESERVES_UV_BITS

This symbol contains the number of bits a variable of type NVTYPE can preserve of a variable of type UVTYPE.

#NV_ZERO_IS_ALLBITS_ZERO

This symbol, if defined, indicates that a variable of type NVTYPE stores 0.0 in memory as all bits zero.

#NVMANTBITS

This symbol, if defined, tells how many mantissa bits (not including implicit bit) there are in a Perl NV. This depends on which floating point type was chosen.

#NVSIZE

This symbol contains the sizeof(NV). Note that some floating point formats have unused bytes. The most notable example is the x86* 80-bit extended precision which comes in byte sizes of 12 and 16 (for 32 and 64 bit platforms, respectively), but which only uses 10 bytes. Perl compiled with -Duselongdouble on x86* is like this.

#NVTYPE

This symbol defines the C type used for Perl's NV.

#General Configuration

This section contains configuration information not otherwise found in the more specialized sections of this document. At the end is a list of #defines whose name should be enough to tell you what they do, and a list of #defines which tell you if you need to #include files to get the corresponding functionality.

#ASCIIish

A preprocessor symbol that is defined iff the system is an ASCII platform; this symbol would not be defined on "EBCDIC" platforms.

#ifdef  ASCIIish

#BYTEORDER

This symbol holds the hexadecimal constant defined in byteorder, in a UV, i.e. 0x1234 or 0x4321 or 0x12345678, etc... If the compiler supports cross-compiling or multiple-architecture binaries, use compiler-defined macros to determine the byte order.

#CAT2

This macro concatenates 2 tokens together.

token  CAT2(token x, token y)

#CHARBITS

This symbol contains the size of a char, so that the C preprocessor can make decisions based on it.

#DB_VERSION_MAJOR_CFG

This symbol, if defined, defines the major version number of Berkeley DB found in the db.h header when Perl was configured.

#DB_VERSION_MINOR_CFG

This symbol, if defined, defines the minor version number of Berkeley DB found in the db.h header when Perl was configured. For DB version 1 this is always 0.

#DB_VERSION_PATCH_CFG

This symbol, if defined, defines the patch version number of Berkeley DB found in the db.h header when Perl was configured. For DB version 1 this is always 0.

#DEFAULT_INC_EXCLUDES_DOT

This symbol, if defined, removes the legacy default behavior of including '.' at the end of @INC.

#DLSYM_NEEDS_UNDERSCORE

This symbol, if defined, indicates that we need to prepend an underscore to the symbol name before calling dlsym(). This only makes sense if you *have* dlsym, which we will presume is the case if you're using dl_dlopen.xs.

#Drand01

This macro is to be used to generate uniformly distributed random numbers over the range [0., 1.[. You may have to supply an 'extern double drand48();' in your program since SunOS 4.1.3 doesn't provide you with anything relevant in its headers. See "HAS_DRAND48_PROTO".

double  Drand01()

#EBCDIC

This symbol, if defined, indicates that this system uses EBCDIC encoding.

#HAS_CSH

This symbol, if defined, indicates that the C-shell exists.

#HAS_GETHOSTNAME

This symbol, if defined, indicates that the C program may use the gethostname() routine to derive the host name. See also "HAS_UNAME" and "PHOSTNAME".

#HAS_GNULIBC

This symbol, if defined, indicates to the C program that the GNU C library is being used. A better check is to use the __GLIBC__ and __GLIBC_MINOR__ symbols supplied with glibc.

#HAS_LGAMMA

This symbol, if defined, indicates that the lgamma routine is available to do the log gamma function. See also "HAS_TGAMMA" and "HAS_LGAMMA_R".

#HAS_LGAMMA_R

This symbol, if defined, indicates that the lgamma_r routine is available to do the log gamma function without using the global signgam variable.

#HAS_NON_INT_BITFIELDS

This symbol, if defined, indicates that the C compiler accepts, without error or warning, struct bitfields that are declared with sizes other than plain 'int'; for example 'unsigned char' is accepted.

#HAS_PRCTL_SET_NAME

This symbol, if defined, indicates that the prctl routine is available to set process title and supports PR_SET_NAME.

#HAS_PROCSELFEXE

This symbol is defined if PROCSELFEXE_PATH is a symlink to the absolute pathname of the executing program.

#HAS_PSEUDOFORK

This symbol, if defined, indicates that an emulation of the fork routine is available.

#HAS_REGCOMP

This symbol, if defined, indicates that the regcomp() routine is available to do some regular pattern matching (usually on POSIX.2 conforming systems).

#HAS_SETPGID

This symbol, if defined, indicates that the setpgid(pid, gpid) routine is available to set process group ID.

#HAS_SIGSETJMP

This variable indicates to the C program that the sigsetjmp() routine is available to save the calling process's registers and stack environment for later use by siglongjmp(), and to optionally save the process's signal mask. See "Sigjmp_buf", "Sigsetjmp", and "Siglongjmp".

#HAS_STRUCT_CMSGHDR

This symbol, if defined, indicates that the struct cmsghdr is supported.

#HAS_STRUCT_MSGHDR

This symbol, if defined, indicates that the struct msghdr is supported.

#HAS_TGAMMA

This symbol, if defined, indicates that the tgamma routine is available to do the gamma function. See also "HAS_LGAMMA".

#HAS_UNAME

This symbol, if defined, indicates that the C program may use the uname() routine to derive the host name. See also "HAS_GETHOSTNAME" and "PHOSTNAME".

#HAS_UNION_SEMUN

This symbol, if defined, indicates that the union semun is defined by including sys/sem.h. If not, the user code probably needs to define it as:

union semun {
int val;
struct semid_ds *buf;
unsigned short *array;
}

#I_DIRENT

This symbol, if defined, indicates to the C program that it should include dirent.h. Using this symbol also triggers the definition of the Direntry_t define which ends up being 'struct dirent' or 'struct direct' depending on the availability of dirent.h.

#ifdef I_DIRENT
    #include <dirent.h>
#endif

#I_POLL

This symbol, if defined, indicates that poll.h exists and should be included. (see also "HAS_POLL")

#ifdef I_POLL
    #include <poll.h>
#endif

#I_SYS_RESOURCE

This symbol, if defined, indicates to the C program that it should include sys/resource.h.

#ifdef I_SYS_RESOURCE
    #include <sys_resource.h>
#endif

#LIBM_LIB_VERSION

This symbol, if defined, indicates that libm exports _LIB_VERSION and that math.h defines the enum to manipulate it.

#NEED_VA_COPY

This symbol, if defined, indicates that the system stores the variable argument list datatype, va_list, in a format that cannot be copied by simple assignment, so that some other means must be used when copying is required. As such systems vary in their provision (or non-provision) of copying mechanisms, handy.h defines a platform- independent macro, Perl_va_copy(src, dst), to do the job.

#OSNAME

This symbol contains the name of the operating system, as determined by Configure. You shouldn't rely on it too much; the specific feature tests from Configure are generally more reliable.

#OSVERS

This symbol contains the version of the operating system, as determined by Configure. You shouldn't rely on it too much; the specific feature tests from Configure are generally more reliable.

#PERL_USE_GCC_BRACE_GROUPS

This C pre-processor value, if defined, indicates that it is permissible to use the GCC brace groups extension. However, use of this extension is DISCOURAGED. Use a static inline function instead.

The extension, of the form

({ statement ... })

turns the block consisting of statement ... into an expression with a value, unlike plain C language blocks. This can present optimization possibilities, BUT, unless you know for sure that this will never be compiled without this extension being available and not forbidden, you need to specify an alternative. Thus two code paths have to be maintained, which can get out-of-sync. All these issues are solved by using a static inline function instead.

Perl can be configured to not use this feature by passing the parameter -Accflags=-DPERL_GCC_BRACE_GROUPS_FORBIDDEN to Configure.

#ifdef  PERL_USE_GCC_BRACE_GROUPS

#PHOSTNAME

This symbol, if defined, indicates the command to feed to the popen() routine to derive the host name. See also "HAS_GETHOSTNAME" and "HAS_UNAME". Note that the command uses a fully qualified path, so that it is safe even if used by a process with super-user privileges.

#PROCSELFEXE_PATH

If HAS_PROCSELFEXE is defined this symbol is the filename of the symbolic link pointing to the absolute pathname of the executing program.

#PTRSIZE

This symbol contains the size of a pointer, so that the C preprocessor can make decisions based on it. It will be sizeof(void *) if the compiler supports (void *); otherwise it will be sizeof(char *).

#RANDBITS

This symbol indicates how many bits are produced by the function used to generate normalized random numbers. Values include 15, 16, 31, and 48.

#seedDrand01

This symbol defines the macro to be used in seeding the random number generator (see "Drand01").

void  seedDrand01(Rand_seed_t x)

#SELECT_MIN_BITS

This symbol holds the minimum number of bits operated by select. That is, if you do select(n, ...), how many bits at least will be cleared in the masks if some activity is detected. Usually this is either n or 32*ceil(n/32), especially many little-endians do the latter. This is only useful if you have select(), naturally.

#SETUID_SCRIPTS_ARE_SECURE_NOW

This symbol, if defined, indicates that the bug that prevents setuid scripts from being secure is not present in this kernel.

#ST_DEV_SIGN

This symbol holds the signedness of struct stat's st_dev. 1 for unsigned, -1 for signed.

#ST_DEV_SIZE

This variable contains the size of struct stat's st_dev in bytes.

#STRINGIFY

This macro surrounds its token with double quotes.

string  STRINGIFY(token x)

#List of capability HAS_foo symbols

This is a list of those symbols that dont appear elsewhere in ths document that indicate if the current platform has a certain capability. Their names all begin with HAS_. Only those symbols whose capability is directly derived from the name are listed here. All others have their meaning expanded out elsewhere in this document. This (relatively) compact list is because we think that the expansion would add little or no value and take up a lot of space (because there are so many). If you think certain ones should be expanded, send email to perl5-porters@perl.org.

Each symbol here will be #defined if and only if the platform has the capability. If you need more detail, see the corresponding entry in config.h. For convenience, the list is split so that the ones that indicate there is a reentrant version of a capability are listed separately

HAS__FWALK, HAS_ACCEPT4, HAS_ACCESS, HAS_ACCESSX, HAS_ACOSH, HAS_AINTL, HAS_ALARM, HAS_ASINH, HAS_ATANH, HAS_ATOLL, HAS_CBRT, HAS_CHOWN, HAS_CHROOT, HAS_CHSIZE, HAS_CLEARENV, HAS_COPYSIGN, HAS_COPYSIGNL, HAS_CRYPT, HAS_CTERMID, HAS_CUSERID, HAS_DIRFD, HAS_DLADDR, HAS_DLERROR, HAS_EACCESS, HAS_ENDHOSTENT, HAS_ENDNETENT, HAS_ENDPROTOENT, HAS_ENDSERVENT, HAS_ERF, HAS_ERFC, HAS_EXPM1, HAS_EXP2, HAS_FCHMOD, HAS_FCHMODAT, HAS_FCHOWN, HAS_FD_SET, HAS_FDIM, HAS_FEGETROUND, HAS_FFS, HAS_FFSL, HAS_FGETPOS, HAS_FLOCK, HAS_FMA, HAS_FMAX, HAS_FMIN, HAS_FORK, HAS_FSEEKO, HAS_FSETPOS, HAS_FSYNC, HAS_FTELLO, HAS_GAI_STRERROR, HAS_GETADDRINFO, HAS_GETCWD, HAS_GETESPWNAM, HAS_GETGROUPS, HAS_GETHOSTBYADDR, HAS_GETHOSTBYNAME, HAS_GETHOSTENT, HAS_GETLOGIN, HAS_GETNAMEINFO, HAS_GETNETBYADDR, HAS_GETNETBYNAME, HAS_GETNETENT, HAS_GETPAGESIZE, HAS_GETPGID, HAS_GETPGRP, HAS_GETPGRP2, HAS_GETPPID, HAS_GETPRIORITY, HAS_GETPROTOBYNAME, HAS_GETPROTOBYNUMBER, HAS_GETPROTOENT, HAS_GETPRPWNAM, HAS_GETSERVBYNAME, HAS_GETSERVBYPORT, HAS_GETSERVENT, HAS_GETSPNAM, HAS_HTONL, HAS_HTONS, HAS_HYPOT, HAS_ILOGBL, HAS_INET_ATON, HAS_INETNTOP, HAS_INETPTON, HAS_IP_MREQ, HAS_IP_MREQ_SOURCE, HAS_IPV6_MREQ, HAS_IPV6_MREQ_SOURCE, HAS_ISASCII, HAS_ISBLANK, HAS_ISLESS, HAS_KILLPG, HAS_LCHOWN, HAS_LINK, HAS_LINKAT, HAS_LLROUND, HAS_LOCKF, HAS_LOGB, HAS_LOG1P, HAS_LOG2, HAS_LROUND, HAS_LSTAT, HAS_MADVISE, HAS_MBLEN, HAS_MBRLEN, HAS_MBRTOWC, HAS_MBSTOWCS, HAS_MBTOWC, HAS_MEMMEM, HAS_MEMRCHR, HAS_MKDTEMP, HAS_MKFIFO, HAS_MKOSTEMP, HAS_MKSTEMP, HAS_MKSTEMPS, HAS_MMAP, HAS_MPROTECT, HAS_MSG, HAS_MSYNC, HAS_MUNMAP, HAS_NEARBYINT, HAS_NEXTAFTER, HAS_NICE, HAS_NTOHL, HAS_NTOHS, HAS_PATHCONF, HAS_PAUSE, HAS_PHOSTNAME, HAS_PIPE, HAS_PIPE2, HAS_PRCTL, HAS_PTRDIFF_T, HAS_READLINK, HAS_READV, HAS_RECVMSG, HAS_REMQUO, HAS_RENAME, HAS_RENAMEAT, HAS_RINT, HAS_ROUND, HAS_SCALBNL, HAS_SEM, HAS_SENDMSG, HAS_SETEGID, HAS_SETENV, HAS_SETEUID, HAS_SETGROUPS, HAS_SETHOSTENT, HAS_SETLINEBUF, HAS_SETNETENT, HAS_SETPGRP, HAS_SETPGRP2, HAS_SETPRIORITY, HAS_SETPROCTITLE, HAS_SETPROTOENT, HAS_SETREGID, HAS_SETRESGID, HAS_SETRESUID, HAS_SETREUID, HAS_SETRGID, HAS_SETRUID, HAS_SETSERVENT, HAS_SETSID, HAS_SHM, HAS_SIGACTION, HAS_SIGPROCMASK, HAS_SIN6_SCOPE_ID, HAS_SNPRINTF, HAS_STAT, HAS_STRCOLL, HAS_STRERROR_L, HAS_STRLCAT, HAS_STRLCPY, HAS_STRNLEN, HAS_STRTOD, HAS_STRTOL, HAS_STRTOLL, HAS_STRTOQ, HAS_STRTOUL, HAS_STRTOULL, HAS_STRTOUQ, HAS_STRXFRM, HAS_STRXFRM_L, HAS_SYMLINK, HAS_SYS_ERRLIST, HAS_SYSCALL, HAS_SYSCONF, HAS_SYSTEM, HAS_TCGETPGRP, HAS_TCSETPGRP, HAS_TOWLOWER, HAS_TOWUPPER, HAS_TRUNCATE, HAS_TRUNCL, HAS_UALARM, HAS_UMASK, HAS_UNLINKAT, HAS_UNSETENV, HAS_VFORK, HAS_VSNPRINTF, HAS_WAITPID, HAS_WAIT4, HAS_WCRTOMB, HAS_WCSCMP, HAS_WCSTOMBS, HAS_WCSXFRM, HAS_WCTOMB, HAS_WRITEV

And, the reentrant capabilities:

HAS_CRYPT_R, HAS_CTERMID_R, HAS_DRAND48_R, HAS_ENDHOSTENT_R, HAS_ENDNETENT_R, HAS_ENDPROTOENT_R, HAS_ENDSERVENT_R, HAS_GETGRGID_R, HAS_GETGRNAM_R, HAS_GETHOSTBYADDR_R, HAS_GETHOSTBYNAME_R, HAS_GETHOSTENT_R, HAS_GETLOGIN_R, HAS_GETNETBYADDR_R, HAS_GETNETBYNAME_R, HAS_GETNETENT_R, HAS_GETPROTOBYNAME_R, HAS_GETPROTOBYNUMBER_R, HAS_GETPROTOENT_R, HAS_GETPWNAM_R, HAS_GETPWUID_R, HAS_GETSERVBYNAME_R, HAS_GETSERVBYPORT_R, HAS_GETSERVENT_R, HAS_GETSPNAM_R, HAS_RANDOM_R, HAS_READDIR_R, HAS_SETHOSTENT_R, HAS_SETNETENT_R, HAS_SETPROTOENT_R, HAS_SETSERVENT_R, HAS_SRANDOM_R, HAS_SRAND48_R, HAS_STRERROR_R, HAS_TMPNAM_R, HAS_TTYNAME_R

Example usage:

#ifdef HAS_STRNLEN
  use strnlen()
#else
  use an alternative implementation
#endif

#List of #include needed symbols

This list contains symbols that indicate if certain #include files are present on the platform. If your code accesses the functionality that one of these is for, you will need to #include it if the symbol on this list is #defined. For more detail, see the corresponding entry in config.h.

I_ARPA_INET, I_BFD, I_CRYPT, I_DBM, I_DLFCN, I_EXECINFO, I_FP, I_FP_CLASS, I_GDBM, I_GDBM_NDBM, I_GDBMNDBM, I_GRP, I_IEEEFP, I_INTTYPES, I_LIBUTIL, I_MNTENT, I_NDBM, I_NET_ERRNO, I_NETDB, I_NETINET_IN, I_NETINET_TCP, I_PROT, I_PWD, I_RPCSVC_DBM, I_SGTTY, I_SHADOW, I_STDBOOL, I_STDINT, I_SUNMATH, I_SYS_ACCESS, I_SYS_IOCTL, I_SYS_MOUNT, I_SYS_PARAM, I_SYS_POLL, I_SYS_SECURITY, I_SYS_SELECT, I_SYS_STAT, I_SYS_STATVFS, I_SYS_SYSCALL, I_SYS_TIME, I_SYS_TIME_KERNEL, I_SYS_TIMES, I_SYS_TYPES, I_SYS_UN, I_SYS_VFS, I_SYS_WAIT, I_SYSLOG, I_SYSMODE, I_SYSUIO, I_SYSUTSNAME, I_TERMIO, I_TERMIOS, I_UNISTD, I_USTAT, I_VFORK, I_WCHAR, I_WCTYPE

Example usage:

#ifdef I_WCHAR
  #include <wchar.h>
#endif

#Global Variables

These variables are global to an entire process. They are shared between all interpreters and all threads in a process. Any variables not documented here may be changed or removed without notice, so don't use them! If you feel you really do need to use an unlisted variable, first send email to perl5-porters@perl.org. It may be that someone there will point out a way to accomplish what you need without using an internal variable. But if not, you should get a go-ahead to document and then use the variable.

#PL_check

Array, indexed by opcode, of functions that will be called for the "check" phase of optree building during compilation of Perl code. For most (but not all) types of op, once the op has been initially built and populated with child ops it will be filtered through the check function referenced by the appropriate element of this array. The new op is passed in as the sole argument to the check function, and the check function returns the completed op. The check function may (as the name suggests) check the op for validity and signal errors. It may also initialise or modify parts of the ops, or perform more radical surgery such as adding or removing child ops, or even throw the op away and return a different op in its place.

This array of function pointers is a convenient place to hook into the compilation process. An XS module can put its own custom check function in place of any of the standard ones, to influence the compilation of a particular type of op. However, a custom check function must never fully replace a standard check function (or even a custom check function from another module). A module modifying checking must instead wrap the preexisting check function. A custom check function must be selective about when to apply its custom behaviour. In the usual case where it decides not to do anything special with an op, it must chain the preexisting op function. Check functions are thus linked in a chain, with the core's base checker at the end.

For thread safety, modules should not write directly to this array. Instead, use the function "wrap_op_checker".

#PL_infix_plugin

NOTE: PL_infix_plugin is experimental and may change or be removed without notice.

NOTE: This API exists entirely for the purpose of making the CPAN module XS::Parse::Infix work. It is not expected that additional modules will make use of it; rather, that they should use XS::Parse::Infix to provide parsing of new infix operators.

Function pointer, pointing at a function used to handle extended infix operators. The function should be declared as

int infix_plugin_function(pTHX_
        char *opname, STRLEN oplen,
        struct Perl_custom_infix **infix_ptr)

The function is called from the tokenizer whenever a possible infix operator is seen. opname points to the operator name in the parser's input buffer, and oplen gives the maximum number of bytes of it that should be consumed; it is not null-terminated. The function is expected to examine the operator name and possibly other state such as %^H, to determine whether it wants to handle the operator name.

As compared to the single stage of PL_keyword_plugin, parsing of additional infix operators occurs in three separate stages. This is because of the more complex interactions it has with the parser, to ensure that operator precedence rules work correctly. These stages are co-ordinated by the use of an additional information structure.

If the function wants to handle the infix operator, it must set the variable pointed to by infix_ptr to the address of a structure that provides this additional information about the subsequent parsing stages. If it does not, it should make a call to the next function in the chain.

This structure has the following definition:

struct Perl_custom_infix {
    enum Perl_custom_infix_precedence prec;
    void (*parse)(pTHX_ SV **opdata,
	struct Perl_custom_infix *);
    OP *(*build_op)(pTHX_ SV **opdata, OP *lhs, OP *rhs,
	struct Perl_custom_infix *);
};

The function must then return an integer giving the number of bytes consumed by the name of this operator. In the case of an operator whose name is composed of identifier characters, this must be equal to oplen. In the case of an operator named by non-identifier characters, this is permitted to be shorter than oplen, and any additional characters after it will not be claimed by the infix operator but instead will be consumed by the tokenizer and parser as normal.

If the optional parse function is provided, it is called immediately by the parser to let the operator's definition consume any additional syntax from the source code. This should not be used for normal operand parsing, but it may be useful when implementing things like parametric operators or meta-operators that consume more syntax themselves. This function may use the variable pointed to by opdata to provide an SV containing additional data to be passed into the build_op function later on.

The information structure gives the operator precedence level in the prec field. This is used to tell the parser how much of the surrounding syntax before and after should be considered as operands to the operator.

The tokenizer and parser will then continue to operate as normal until enough additional input has been parsed to form both the left- and right-hand side operands to the operator, according to the precedence level. At this point the build_op function is called, being passed the left- and right-hand operands as optree fragments. It is expected to combine them into the resulting optree fragment, which it should return.

After the build_op function has returned, if the variable pointed to by opdata was set to a non-NULL value, it will then be destroyed by calling SvREFCNT_dec().

For thread safety, modules should not set this variable directly. Instead, use the function "wrap_infix_plugin".

However, that all said, the introductory note above still applies. This variable is provided in core perl only for the benefit of the XS::Parse::Infix module. That module acts as a central registry for infix operators, automatically handling things like deparse support and discovery/reflection, and these abilities only work because it knows all the registered operators. Other modules should not use this interpreter variable directly to implement them because then those central features would no longer work properly.

Furthermore, it is likely that this (experimental) API will be replaced in a future Perl version by a more complete API that fully implements the central registry and other semantics currently provided by XS::Parse::Infix, once the module has had sufficient experimental testing time. This current mechanism exists only as an interim measure to get to that stage.

#PL_keyword_plugin

NOTE: PL_keyword_plugin is experimental and may change or be removed without notice.

Function pointer, pointing at a function used to handle extended keywords. The function should be declared as

int keyword_plugin_function(pTHX_
        char *keyword_ptr, STRLEN keyword_len,
        OP **op_ptr)

The function is called from the tokeniser, whenever a possible keyword is seen. keyword_ptr points at the word in the parser's input buffer, and keyword_len gives its length; it is not null-terminated. The function is expected to examine the word, and possibly other state such as %^H, to decide whether it wants to handle it as an extended keyword. If it does not, the function should return KEYWORD_PLUGIN_DECLINE, and the normal parser process will continue.

If the function wants to handle the keyword, it first must parse anything following the keyword that is part of the syntax introduced by the keyword. See "Lexer interface" for details.

When a keyword is being handled, the plugin function must build a tree of OP structures, representing the code that was parsed. The root of the tree must be stored in *op_ptr. The function then returns a constant indicating the syntactic role of the construct that it has parsed: KEYWORD_PLUGIN_STMT if it is a complete statement, or KEYWORD_PLUGIN_EXPR if it is an expression. Note that a statement construct cannot be used inside an expression (except via do BLOCK and similar), and an expression is not a complete statement (it requires at least a terminating semicolon).

When a keyword is handled, the plugin function may also have (compile-time) side effects. It may modify %^H, define functions, and so on. Typically, if side effects are the main purpose of a handler, it does not wish to generate any ops to be included in the normal compilation. In this case it is still required to supply an op tree, but it suffices to generate a single null op.

That's how the *PL_keyword_plugin function needs to behave overall. Conventionally, however, one does not completely replace the existing handler function. Instead, take a copy of PL_keyword_plugin before assigning your own function pointer to it. Your handler function should look for keywords that it is interested in and handle those. Where it is not interested, it should call the saved plugin function, passing on the arguments it received. Thus PL_keyword_plugin actually points at a chain of handler functions, all of which have an opportunity to handle keywords, and only the last function in the chain (built into the Perl core) will normally return KEYWORD_PLUGIN_DECLINE.

For thread safety, modules should not set this variable directly. Instead, use the function "wrap_keyword_plugin".

#PL_phase

A value that indicates the current Perl interpreter's phase. Possible values include PERL_PHASE_CONSTRUCT, PERL_PHASE_START, PERL_PHASE_CHECK, PERL_PHASE_INIT, PERL_PHASE_RUN, PERL_PHASE_END, and PERL_PHASE_DESTRUCT.

For example, the following determines whether the interpreter is in global destruction:

if (PL_phase == PERL_PHASE_DESTRUCT) {
    // we are in global destruction
}

PL_phase was introduced in Perl 5.14; in prior perls you can use PL_dirty (boolean) to determine whether the interpreter is in global destruction. (Use of PL_dirty is discouraged since 5.14.)

enum perl_phase  PL_phase

#GV Handling and Stashes

A GV is a structure which corresponds to a Perl typeglob, i.e., *foo. It is a structure that holds a pointer to a scalar, an array, a hash etc, corresponding to $foo, @foo, %foo.

GVs are usually found as values in stashes (symbol table hashes) where Perl stores its global variables.

A stash is a hash that contains all variables that are defined within a package. See "Stashes and Globs" in perlguts

#amagic_call

Perform the overloaded (active magic) operation given by method. method is one of the values found in overload.h.

flags affects how the operation is performed, as follows:

#AMGf_noleft

left is not to be used in this operation.

#AMGf_noright

right is not to be used in this operation.

#AMGf_unary

The operation is done only on just one operand.

#AMGf_assign

The operation changes one of the operands, e.g., $x += 1

SV *       amagic_call(      SV *left, SV *right, int method,
                             int dir)
SV *  Perl_amagic_call(pTHX_ SV *left, SV *right, int method,
                             int dir)

#amagic_deref_call

Perform method overloading dereferencing on ref, returning the dereferenced result. method must be one of the dereference operations given in overload.h.

If overloading is inactive on ref, returns ref itself.

SV *       amagic_deref_call(      SV *ref, int method)
SV *  Perl_amagic_deref_call(pTHX_ SV *ref, int method)

#gv_add_by_type

Make sure there is a slot of type type in the GV gv.

GV *       gv_add_by_type(      GV *gv, svtype type)
GV *  Perl_gv_add_by_type(pTHX_ GV *gv, svtype type)

#Gv_AMupdate

Recalculates overload magic in the package given by stash.

Returns:

#1 on success and there is some overload

#0 if there is no overload

#-1 if some error occurred and it couldn't croak (because destructing is true).

int       Gv_AMupdate(      HV *stash, bool destructing)
int  Perl_Gv_AMupdate(pTHX_ HV *stash, bool destructing)

#gv_autoload_pv

#gv_autoload_pvn

#gv_autoload_sv

#gv_autoload4

These each search for an AUTOLOAD method, returning NULL if not found, or else returning a pointer to its GV, while setting the package $AUTOLOAD variable to the name (fully qualified). Also, if found and the GV's CV is an XSUB, the CV's PV will be set to the name, and its stash will be set to the stash of the GV.

Searching is done in MRO order, as specified in "gv_fetchmeth", beginning with stash if it isn't NULL.

gv_autoload4) has a method parameter; the others a flags one (both types explained below). Otherwise, the forms differ only in how the name is specified.

In gv_autoload_pv, namepv is a C language NUL-terminated string.

In gv_autoload_pvn and gv_autoload4), name points to the first byte of the name, and an additional parameter, len, specifies its length in bytes. Hence, *name may contain embedded-NUL characters.

In gv_autoload_sv, *namesv is an SV, and the name is the PV extracted from that using "SvPV". If the SV is marked as being in UTF-8, the extracted PV will also be.

The other way to indicate that the name is encoded as UTF-8 is to set the SVf_UTF8 bit in flags for the forms that have that parameter. The name is never considered to be UTF-8 in gv_autoload4.

The method parameter in gv_autoload4 is used only to indicate that the name is for a method (non-zero), or not (zero). The other forms use the GV_AUTOLOAD_ISMETHOD bit in flags to indicate this.

The only other significant value in flags currently is GV_SUPER to indicate, if set, to skip searching for the name in stash.

GV *       gv_autoload_pv (      NOCHECK HV *stash,
                                 const char *namepv, U32 flags)
GV *  Perl_gv_autoload_pv (pTHX_ NOCHECK HV *stash,
                                 const char *namepv, U32 flags)
GV *       gv_autoload_pvn(      NOCHECK HV *stash,
                                 const char *name, STRLEN len,
                                 U32 flags)
GV *  Perl_gv_autoload_pvn(pTHX_ NOCHECK HV *stash,
                                 const char *name, STRLEN len,
                                 U32 flags)
GV *       gv_autoload_sv (      NOCHECK HV *stash, SV *namesv,
                                 U32 flags)
GV *  Perl_gv_autoload_sv (pTHX_ NOCHECK HV *stash, SV *namesv,
                                 U32 flags)
GV *       gv_autoload4   (      HV *stash, const char *name,
                                 STRLEN len, I32 method
)

#gv_AVadd

#gv_HVadd

#gv_IOadd

#gv_SVadd

Make sure there is a slot of the given type (AV, HV, IO, SV) in the GV gv.

GV *       gv_AVadd(      GV *gv)
GV *  Perl_gv_AVadd(pTHX_ GV *gv)
GV *       gv_HVadd(      GV *gv)
GV *  Perl_gv_HVadd(pTHX_ GV *gv)
GV *       gv_IOadd(      GV *gv)
GV *  Perl_gv_IOadd(pTHX_ GV *gv)
GV *       gv_SVadd(      GV *gv)
GV *  Perl_gv_SVadd(pTHX_ GV *gv)

#gv_const_sv

If gv is a typeglob whose subroutine entry is a constant sub eligible for inlining, or gv is a placeholder reference that would be promoted to such a typeglob, then returns the value returned by the sub. Otherwise, returns NULL.

SV *       gv_const_sv(      GV *gv)
SV *  Perl_gv_const_sv(pTHX_ GV *gv)

#gv_efullname3

#gv_efullname4

#gv_fullname3

#gv_fullname4

Place the full package name of gv into sv. The gv_e* forms return instead the effective package name (see "HvENAME").

If prefix is non-NULL, it is considered to be a C language NUL-terminated string, and the stored name will be prefaced with it.

The other difference between the functions is that the *4 forms have an extra parameter, keepmain. If true an initial main:: in the name is kept; if false it is stripped. With the *3 forms, it is always kept.

void       gv_efullname3(      SV *sv, const GV *gv,
                               const char *prefix)
void  Perl_gv_efullname3(pTHX_ SV *sv, const GV *gv,
                               const char *prefix)
void       gv_efullname4(      SV *sv, const GV *gv,
                               const char *prefix, bool keepmain)
void  Perl_gv_efullname4(pTHX_ SV *sv, const GV *gv,
                               const char *prefix, bool keepmain)
void       gv_fullname3 (      SV *sv, const GV *gv,
                               const char *prefix)
void  Perl_gv_fullname3 (pTHX_ SV *sv, const GV *gv,
                               const char *prefix)
void       gv_fullname4 (      SV *sv, const GV *gv,
                               const char *prefix, bool keepmain)
void  Perl_gv_fullname4 (pTHX_ SV *sv, const GV *gv,
                               const char *prefix, bool keepmain)

#gv_fetchfile

#gv_fetchfile_flags

These return the debugger glob for the file (compiled by Perl) whose name is given by the name parameter.

There are currently exactly two differences between these functions.

The name parameter to gv_fetchfile is a C string, meaning it is NUL-terminated; whereas the name parameter to gv_fetchfile_flags is a Perl string, whose length (in bytes) is passed in via the namelen parameter This means the name may contain embedded NUL characters. namelen doesn't exist in plain gv_fetchfile).

The other difference is that gv_fetchfile_flags has an extra flags parameter, which is currently completely ignored, but allows for possible future extensions.

GV *       gv_fetchfile      (      const char *name)
GV *  Perl_gv_fetchfile      (pTHX_ const char *name)
GV *       gv_fetchfile_flags(      const char * const name,
                                    const STRLEN len,
                                    const U32 flags)
GV *  Perl_gv_fetchfile_flags(pTHX_ const char * const name,
                                    const STRLEN len,
                                    const U32 flags)

#gv_fetchmeth

#gv_fetchmeth_autoload

#gv_fetchmeth_pv

#gv_fetchmeth_pv_autoload

#gv_fetchmeth_pvn

#gv_fetchmeth_pvn_autoload

#gv_fetchmeth_sv

#gv_fetchmeth_sv_autoload

These each look for a glob with name name, containing a defined subroutine, returning the GV of that glob if found, or NULL if not.

You probably want to use the "gv_fetchmethod" family of functions instead.

Searching is always done in the following order, with some steps skipped depending on various criteria. The first match found is used, ending the search. gv_fetchmeth_pv and gv_fetchmeth_pv_autoload lack a flags parameter, so in the following, consider flags to be zero for those two functions.

1. stash is searched first, unless stash either is NULL or GV_SUPER is set in flags.

2. Stashes accessible via @ISA are searched next.

   Searching is conducted according to MRO order.

3. UNIVERSAL:: is searched unless GV_NOUNIVERSAL is set.

4. Autoloaded subroutines are then looked for, but only for the forms whose names end in _autoload, and when stash is not NULL and GV_SUPER is not set.

The argument level should be either 0 or -1.

#If -1

No method caching is done.

#If 0

If GV_SUPER is not set in flags, the method found is cached in stash.

If GV_SUPER is set in flags, the method is cached in the super cache for stash.

If the method is not found a negative cache entry is added.

Note that subroutines found in UNIVERSAL:: are not cached, though this may change.

The GV returned from these may be a method cache entry, which is not visible to Perl code. So when calling "call_sv", you should not use the GV directly; instead, you should use the method's CV, which can be obtained from the GV with the GvCV macro. For an autoloaded subroutine without a stub, GvCV() of the result may be zero.

The only other significant value for flags is SVf_UTF8, indicating that name is to be treated as being encoded in UTF-8. Since plain gv_fetchmeth and gv_fetchmeth_autoload lack a flags parameter, name is never UTF-8.

Otherwise, the functions behave identically, except as noted below.

In gv_fetchmeth_pv and gv_fetchmeth_pv_autoload, name is a C language NUL-terminated string.

In gv_fetchmeth, gv_fetchmeth_pvn, gv_fetchmeth_autoload, and gv_fetchmeth_pvn_autoload, name points to the first byte of the name, and an additional parameter, len, specifies its length in bytes. Hence, the name may contain embedded-NUL characters.

In gv_fetchmeth_sv and gv_fetchmeth_sv_autoload, *name is an SV, and the name is the PV extracted from that, using "SvPV". If the SV is marked as being in UTF-8, the extracted PV will also be. Including SVf_UTF8 in flags will force the name to be considered to be UTF-8 even if the SV is not so marked.

GV *       gv_fetchmeth             (      NOCHECK HV *stash,
                                           const char *name,
                                           STRLEN len, I32 level)
GV *       gv_fetchmeth_autoload    (      NOCHECK HV *stash,
                                           const char *name,
                                           STRLEN len, I32 level)
GV *       gv_fetchmeth_pv          (      NOCHECK HV *stash,
                                           const char *name,
                                           I32 level, U32 flags)
GV *  Perl_gv_fetchmeth_pv          (pTHX_ NOCHECK HV *stash,
                                           const char *name,
                                           I32 level, U32 flags)
GV *       gv_fetchmeth_pv_autoload (      NOCHECK HV *stash,
                                           const char *name,
                                           I32 level, U32 flags)
GV *  Perl_gv_fetchmeth_pv_autoload (pTHX_ NOCHECK HV *stash,
                                           const char *name,
                                           I32 level, U32 flags)
GV *       gv_fetchmeth_pvn         (      NOCHECK HV *stash,
                                           const char *name,
                                           STRLEN len, I32 level,
                                           U32 flags)
GV *  Perl_gv_fetchmeth_pvn         (pTHX_ NOCHECK HV *stash,
                                           const char *name,
                                           STRLEN len, I32 level,
                                           U32 flags)
GV *       gv_fetchmeth_pvn_autoload(      NOCHECK HV *stash,
                                           const char *name,
                                           STRLEN len, I32 level,
                                           U32 flags)
GV *  Perl_gv_fetchmeth_pvn_autoload(pTHX_ NOCHECK HV *stash,
                                           const char *name,
                                           STRLEN len, I32 level,
                                           U32 flags)
GV *       gv_fetchmeth_sv          (      NOCHECK HV *stash,
                                           SV *namesv, I32 level,
                                           U32 flags)
GV *  Perl_gv_fetchmeth_sv          (pTHX_ NOCHECK HV *stash,
                                           SV *namesv, I32 level,
                                           U32 flags)
GV *       gv_fetchmeth_sv_autoload (      NOCHECK HV *stash,
                                           SV *namesv, I32 level,
                                           U32 flags)
GV *  Perl_gv_fetchmeth_sv_autoload (pTHX_ NOCHECK HV *stash,
                                           SV *namesv, I32 level,
                                           U32 flags)

#gv_fetchmethod

#gv_fetchmethod_autoload

These each return the glob which contains the subroutine to call to invoke the method on the stash. In fact in the presence of autoloading this may be the glob for "AUTOLOAD". In this case the corresponding variable $AUTOLOAD is already setup.

The third parameter of gv_fetchmethod_autoload determines whether AUTOLOAD lookup is performed if the given method is not present: non-zero means yes, look for AUTOLOAD; zero means no, don't look for AUTOLOAD. Calling gv_fetchmethod is equivalent to calling gv_fetchmethod_autoload with a non-zero autoload parameter.

These functions grant "SUPER" token as a prefix of the method name. Note that if you want to keep the returned glob for a long time, you need to check for it being "AUTOLOAD", since at the later time the call may load a different subroutine due to $AUTOLOAD changing its value. Use the glob created as a side effect to do this.

These functions have the same side-effects as gv_fetchmeth with level==0. The warning against passing the GV returned by gv_fetchmeth to call_sv applies equally to these functions.

GV *       gv_fetchmethod         (      NOCHECK HV *stash,
                                         const char *name)
GV *  Perl_gv_fetchmethod         (pTHX_ NOCHECK HV *stash,
                                         const char *name)
GV *       gv_fetchmethod_autoload(      NOCHECK HV *stash,
                                         const char *name,
                                         I32 autoload)
GV *  Perl_gv_fetchmethod_autoload(pTHX_ NOCHECK HV *stash,
                                         const char *name,
                                         I32 autoload)

#gv_fetchpv

#gv_fetchpvn

#gv_fetchpvn_flags

#gv_fetchpvs

#gv_fetchsv

#gv_fetchsv_nomg

These all return the GV of type sv_type whose name is given by the inputs, or NULL if no GV of that name and type could be found. See "Stashes and Globs" in perlguts.

The only differences are how the input name is specified, and if 'get' magic is normally used in getting that name.

Don't be fooled by the fact that only one form has flags in its name. They all have a flags parameter in fact, and all the flag bits have the same meanings for all

If any of the flags GV_ADD, GV_ADDMG, GV_ADDWARN, GV_ADDMULTI, or GV_NOINIT is set, a GV is created if none already exists for the input name and type. However, GV_ADDMG will only do the creation for magical GV's. For all of these flags except GV_NOINIT, "gv_init_pvn" is called after the addition. GV_ADDWARN is used when the caller expects that adding won't be necessary because the symbol should already exist; but if not, add it anyway, with a warning that it was unexpectedly absent. The GV_ADDMULTI flag means to pretend that the GV has been seen before (i.e., suppress "Used once" warnings).

The flag GV_NOADD_NOINIT causes "gv_init_pvn" not be to called if the GV existed but isn't PVGV.

If the SVf_UTF8 bit is set, the name is treated as being encoded in UTF-8; otherwise the name won't be considered to be UTF-8 in the pv-named forms, and the UTF-8ness of the underlying SVs will be used in the sv forms.

If the flag GV_NOTQUAL is set, the caller warrants that the input name is a plain symbol name, not qualified with a package, otherwise the name is checked for being a qualified one.

In gv_fetchpv, nambeg is a C string, NUL-terminated with no intermediate NULs.

In gv_fetchpvs, name is a literal C string, hence is enclosed in double quotes.

gv_fetchpvn and gv_fetchpvn_flags are identical. In these, <nambeg> is a Perl string whose byte length is given by full_len, and may contain embedded NULs.

In gv_fetchsv and gv_fetchsv_nomg, the name is extracted from the PV of the input name SV. The only difference between these two forms is that 'get' magic is normally done on name in gv_fetchsv, and always skipped with gv_fetchsv_nomg. Including GV_NO_SVGMAGIC in the flags parameter to gv_fetchsv makes it behave identically to gv_fetchsv_nomg.

GV *       gv_fetchpv       (      const char *nambeg, I32 flags,
                                   const svtype sv_type)
GV *  Perl_gv_fetchpv       (pTHX_ const char *nambeg, I32 flags,
                                   const svtype sv_type)
GV *       gv_fetchpvn      (      const char * nambeg,
                                   STRLEN full_len, I32 flags,
                                   const svtype sv_type)
GV *       gv_fetchpvn_flags(      const char *name, STRLEN len,
                                   I32 flags,
                                   const svtype sv_type)
GV *  Perl_gv_fetchpvn_flags(pTHX_ const char *name, STRLEN len,
                                   I32 flags,
                                   const svtype sv_type)
GV *       gv_fetchpvs      (      "name", I32 flags,
                                   const svtype sv_type)
GV *       gv_fetchsv       (      SV *name, I32 flags,
                                   const svtype sv_type)
GV *  Perl_gv_fetchsv       (pTHX_ SV *name, I32 flags,
                                   const svtype sv_type)
GV *       gv_fetchsv_nomg  (      SV *name, I32 flags,
                                   const svtype sv_type)

#gv_fullname3*

#gv_fullname4*

Described under "gv_efullname3"

#gv_HVadd*

Described under "gv_AVadd"

#gv_init

#gv_init_pv

#gv_init_pvn

#gv_init_sv

These each convert a scalar into a typeglob. This is an incoercible typeglob; assigning a reference to it will assign to one of its slots, instead of overwriting it as happens with typeglobs created by SvSetSV. Converting any scalar that is SvOK() may produce unpredictable results and is reserved for perl's internal use.

gv is the scalar to be converted.

stash is the parent stash/package, if any.

In gv_init and gv_init_pvn, name and len give the name. The name must be unqualified; that is, it must not include the package name. If gv is a stash element, it is the caller's responsibility to ensure that the name passed to this function matches the name of the element. If it does not match, perl's internal bookkeeping will get out of sync. name may contain embedded NUL characters.

gv_init_pv is identical to gv_init_pvn, but takes a NUL-terminated string for the name instead of separate char * and length parameters.

In gv_init_sv, the name is given by sv.

All but gv_init take a flags parameter. Set flags to include SVf_UTF8 if name is a UTF-8 string. In gv_init_sv, if SvUTF8(sv) is non-zero, name will be also be considered to be a UTF-8 string. It's unlikely to be a good idea to pass this particular flag to gv_init_sv, as that would potentially override the (presumaby known) state of sv.

flags can also take the GV_ADDMULTI flag, which means to pretend that the GV has been seen before (i.e., suppress "Used once" warnings).

gv_init is the old form of gv_init_pvn. It does not work with UTF-8 strings, as it has no flags parameter. Setting the multi parameter to non-zero has the same effect as setting the GV_ADDMULTI flag in the other forms.

void       gv_init    (      GV *gv, HV *stash, const char *name,
                             STRLEN len, int multi)
void       gv_init_pv (      GV *gv, HV *stash, const char *name,
                             U32 flags)
void  Perl_gv_init_pv (pTHX_ GV *gv, HV *stash, const char *name,
                             U32 flags)
void       gv_init_pvn(      GV *gv, HV *stash, const char *name,
                             STRLEN len, U32 flags)
void  Perl_gv_init_pvn(pTHX_ GV *gv, HV *stash, const char *name,
                             STRLEN len, U32 flags)
void       gv_init_sv (      GV *gv, HV *stash, SV *namesv,
                             U32 flags)
void  Perl_gv_init_sv (pTHX_ GV *gv, HV *stash, SV *namesv,
                             U32 flags)

#gv_IOadd*

Described under "gv_AVadd"

#gv_name_set

Set the name for GV gv to name which is len bytes long. Thus it may contain embedded NUL characters.

If flags contains SVf_UTF8, the name is treated as being encoded in UTF-8; otherwise not.

void       gv_name_set(      GV *gv, const char *name, U32 len,
                             U32 flags)
void  Perl_gv_name_set(pTHX_ GV *gv, const char *name, U32 len,
                             U32 flags)

#gv_stashpv

#gv_stashpvn

#gv_stashpvs

#gv_stashsv

Note gv_stashsv is strongly preferred for performance reasons.

These each return a pointer to the stash for a specified package.

In gv_stashsv, the package is specified by sv.

In gv_stashpvs, the package is specified by the literal C string enclosed in double quotes.

In the other forms, name specifies the package. In gv_stashpvn, namelen gives the length of the name in bytes, so it may include embedded NUL characters. In gv_stashpv, name ends at the first NUL character.

flags is passed to gv_fetchpvn_flags(), so if set to GV_ADD then the package will be created if it does not already exist. If the package does not exist and flags is 0 (or any other setting that does not create packages) then NULL is returned.

Flags may be one of:

GV_ADD           Create and initialize the package if doesn't
                 already exist
GV_NOADD_NOINIT  Don't create the package,
GV_ADDMG         GV_ADD iff the GV is magical
GV_NOINIT        GV_ADD, but don't initialize
GV_NOEXPAND      Don't expand SvOK() entries to PVGV
SVf_UTF8         The name is in UTF-8

The most important of which are probably GV_ADD and SVf_UTF8.

HV *       gv_stashpv (      const char *name, I32 flags)
HV *  Perl_gv_stashpv (pTHX_ const char *name, I32 flags)
HV *       gv_stashpvn(      const char *name, U32 namelen,
                             I32 flags)
HV *  Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen,
                             I32 flags)
HV*        gv_stashpvs(      "name", I32 create)
HV *       gv_stashsv (      SV *sv, I32 flags)
HV *  Perl_gv_stashsv (pTHX_ SV *sv, I32 flags)

#gv_SVadd*

Described under "gv_AVadd"

#GvAV

Return the AV from the GV.

AV*  GvAV(GV* gv)

#GvCV

Return the CV from the GV.

CV*  GvCV(GV* gv)

#GvHV

Return the HV from the GV.

HV*  GvHV(GV* gv)

#GvREFCNT_inc

#GvREFCNT_inc_simple

#GvREFCNT_inc_simple_NN

These all increment the reference count of the given SV, which must be a GV. They are useful when assigning the result into a typed pointer as they avoid the need to cast the result to the appropriate type.

GV *  GvREFCNT_inc          (GV *gv)
GV *  GvREFCNT_inc_simple   (GV *gv)
GV *  GvREFCNT_inc_simple_NN(GV *gv)

#GvSV

Return the SV from the GV.

Prior to Perl v5.9.3, this would add a scalar if none existed. Nowadays, use "GvSVn" for that, or compile perl with -DPERL_CREATE_GVSV. See perl5100delta.

SV*  GvSV(GV* gv)

#GvSVn

Like "GvSV", but creates an empty scalar if none already exists.

SV*  GvSVn(GV* gv)

#newGVgen

#newGVgen_flags

Create a new, guaranteed to be unique, GV in the package given by the NUL-terminated C language string pack, and return a pointer to it.

For newGVgen or if flags in newGVgen_flags is 0, pack is to be considered to be encoded in Latin-1. The only other legal flags value is SVf_UTF8, which indicates pack is to be considered to be encoded in UTF-8.

GV *       newGVgen      (      const char *pack)
GV *       newGVgen_flags(      const char *pack, U32 flags)
GV *  Perl_newGVgen_flags(pTHX_ const char *pack, U32 flags)

#PL_curstash

The stash for the package code will be compiled into.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

HV*  PL_curstash

#PL_defgv

The GV representing *_. Useful for access to $_.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

GV *  PL_defgv

#PL_defoutgv

See "setdefout".

#PL_defstash

Described in perlguts.

#save_gp

Saves the current GP of gv on the save stack to be restored on scope exit.

If empty is true, replace the GP with a new GP.

If empty is false, mark gv with GVf_INTRO so the next reference assigned is localized, which is how local *foo = $someref; works.

void       save_gp(      GV *gv, I32 empty)
void  Perl_save_gp(pTHX_ GV *gv, I32 empty)

#setdefout

Sets PL_defoutgv, the default file handle for output, to the passed in typeglob. As PL_defoutgv "owns" a reference on its typeglob, the reference count of the passed in typeglob is increased by one, and the reference count of the typeglob that PL_defoutgv points to is decreased by one.

void       setdefout(      GV *gv)
void  Perl_setdefout(pTHX_ GV *gv)

#Hook manipulation

These functions provide convenient and thread-safe means of manipulating hook variables.

#rcpv_copy

refcount increment a shared memory refcounted string, and when the refcount goes to 0 free it using PerlMemShared_free().

It is the callers responsibility to ensure that the pv is the result of a rcpv_new() call.

Returns the same pointer that was passed in.

new = rcpv_copy(pv);

char *       rcpv_copy(      char * const pv)
char *  Perl_rcpv_copy(pTHX_ char * const pv)

#rcpv_free

refcount decrement a shared memory refcounted string, and when the refcount goes to 0 free it using perlmemshared_free().

it is the callers responsibility to ensure that the pv is the result of a rcpv_new() call.

Always returns NULL so it can be used like this:

thing = rcpv_free(thing);

char *       rcpv_free(      char * const pv)
char *  Perl_rcpv_free(pTHX_ char * const pv)

#rcpv_new

Create a new shared memory refcounted string with the requested size, and with the requested initialization and a refcount of 1. The actual space allocated will be 1 byte more than requested and rcpv_new() will ensure that the extra byte is a null regardless of any flags settings.

If the RCPVf_NO_COPY flag is set then the pv argument will be ignored, otherwise the contents of the pv pointer will be copied into the new buffer or if it is NULL the function will do nothing and return NULL.

If the RCPVf_USE_STRLEN flag is set then the len argument is ignored and recomputed using strlen(pv). It is an error to combine RCPVf_USE_STRLEN and RCPVf_NO_COPY at the same time.

Under DEBUGGING rcpv_new() will assert() if it is asked to create a 0 length shared string unless the RCPVf_ALLOW_EMPTY flag is set.

The return value from the function is suitable for passing into rcpv_copy() and rcpv_free(). To access the RCPV * from the returned value use the RCPVx() macro. The 'len' member of the RCPV struct stores the allocated length (including the extra byte), but the RCPV_LEN() macro returns the requested length (not including the extra byte).

Note that rcpv_new() does NOT use a hash table or anything like that to dedupe inputs given the same text content. Each call with a non-null pv parameter will produce a distinct pointer with its own refcount regardless of the input content.

char *       rcpv_new(      const char * const pv, STRLEN len,
                            U32 flags)
char *  Perl_rcpv_new(pTHX_ const char * const pv, STRLEN len,
                            U32 flags)

#wrap_op_checker

Puts a C function into the chain of check functions for a specified op type. This is the preferred way to manipulate the "PL_check" array. opcode specifies which type of op is to be affected. new_checker is a pointer to the C function that is to be added to that opcode's check chain, and old_checker_p points to the storage location where a pointer to the next function in the chain will be stored. The value of new_checker is written into the "PL_check" array, while the value previously stored there is written to *old_checker_p.

"PL_check" is global to an entire process, and a module wishing to hook op checking may find itself invoked more than once per process, typically in different threads. To handle that situation, this function is idempotent. The location *old_checker_p must initially (once per process) contain a null pointer. A C variable of static duration (declared at file scope, typically also marked static to give it internal linkage) will be implicitly initialised appropriately, if it does not have an explicit initialiser. This function will only actually modify the check chain if it finds *old_checker_p to be null. This function is also thread safe on the small scale. It uses appropriate locking to avoid race conditions in accessing "PL_check".

When this function is called, the function referenced by new_checker must be ready to be called, except for *old_checker_p being unfilled. In a threading situation, new_checker may be called immediately, even before this function has returned. *old_checker_p will always be appropriately set before new_checker is called. If new_checker decides not to do anything special with an op that it is given (which is the usual case for most uses of op check hooking), it must chain the check function referenced by *old_checker_p.

Taken all together, XS code to hook an op checker should typically look something like this:

static Perl_check_t nxck_frob;
static OP *myck_frob(pTHX_ OP *op) {
    ...
    op = nxck_frob(aTHX_ op);
    ...
    return op;
}
BOOT:
    wrap_op_checker(OP_FROB, myck_frob, &nxck_frob);

If you want to influence compilation of calls to a specific subroutine, then use "cv_set_call_checker_flags" rather than hooking checking of all entersub ops.

void       wrap_op_checker(      Optype opcode,
                                 Perl_check_t new_checker,
                                 Perl_check_t *old_checker_p)
void  Perl_wrap_op_checker(pTHX_ Optype opcode,
                                 Perl_check_t new_checker,
                                 Perl_check_t *old_checker_p)

#HV Handling

A HV structure represents a Perl hash. It consists mainly of an array of pointers, each of which points to a linked list of HE structures. The array is indexed by the hash function of the key, so each linked list represents all the hash entries with the same hash value. Each HE contains a pointer to the actual value, plus a pointer to a HEK structure which holds the key and hash value.

#get_hv

Returns the HV of the specified Perl hash. flags are passed to gv_fetchpv. If GV_ADD is set and the Perl variable does not exist then it will be created. If flags is zero (ignoring SVf_UTF8) and the variable does not exist then NULL is returned.

NOTE: the perl_get_hv() form is deprecated.

HV *       get_hv(      const char *name, I32 flags)
HV *  Perl_get_hv(pTHX_ const char *name, I32 flags)

#HE

Described in perlguts.

#HEf_SVKEY

This flag, used in the length slot of hash entries and magic structures, specifies the structure contains an SV* pointer where a char* pointer is to be expected. (For information only--not to be used).

#HeHASH

Returns the computed hash stored in the hash entry.

U32  HeHASH(HE* he)

#HeKEY

Returns the actual pointer stored in the key slot of the hash entry. The pointer may be either char* or SV*, depending on the value of HeKLEN(). Can be assigned to. The HePV() or HeSVKEY() macros are usually preferable for finding the value of a key.

void*  HeKEY(HE* he)

#HeKLEN

If this is negative, and amounts to HEf_SVKEY, it indicates the entry holds an SV* key. Otherwise, holds the actual length of the key. Can be assigned to. The HePV() macro is usually preferable for finding key lengths.

STRLEN  HeKLEN(HE* he)

#HePV

Returns the key slot of the hash entry as a char* value, doing any necessary dereferencing of possibly SV* keys. The length of the string is placed in len (this is a macro, so do not use &len). If you do not care about what the length of the key is, you may use the global variable PL_na, though this is rather less efficient than using a local variable. Remember though, that hash keys in perl are free to contain embedded nulls, so using strlen() or similar is not a good way to find the length of hash keys. This is very similar to the SvPV() macro described elsewhere in this document. See also "HeUTF8".

If you are using HePV to get values to pass to newSVpvn() to create a new SV, you should consider using newSVhek(HeKEY_hek(he)) as it is more efficient.

char*  HePV(HE* he, STRLEN len)

#HeSVKEY

Returns the key as an SV*, or NULL if the hash entry does not contain an SV* key.

SV*  HeSVKEY(HE* he)

#HeSVKEY_force

Returns the key as an SV*. Will create and return a temporary mortal SV* if the hash entry contains only a char* key.

SV*  HeSVKEY_force(HE* he)

#HeSVKEY_set

Sets the key to a given SV*, taking care to set the appropriate flags to indicate the presence of an SV* key, and returns the same SV*.

SV*  HeSVKEY_set(HE* he, SV* sv)

#HeUTF8

Returns whether the char * value returned by HePV is encoded in UTF-8, doing any necessary dereferencing of possibly SV* keys. The value returned will be 0 or non-0, not necessarily 1 (or even a value with any low bits set), so do not blindly assign this to a bool variable, as bool may be a typedef for char.

U32  HeUTF8(HE* he)

#HeVAL

Returns the value slot (type SV*) stored in the hash entry. Can be assigned to.

SV *foo= HeVAL(hv);
HeVAL(hv)= sv;

SV*  HeVAL(HE* he)

#HV

Described in perlguts.

#hv_assert

Check that a hash is in an internally consistent state.

void  Perl_hv_assert(pTHX_ HV *hv)

#hv_bucket_ratio

NOTE: hv_bucket_ratio is experimental and may change or be removed without notice.

If the hash is tied dispatches through to the SCALAR tied method, otherwise if the hash contains no keys returns 0, otherwise returns a mortal sv containing a string specifying the number of used buckets, followed by a slash, followed by the number of available buckets.

This function is expensive, it must scan all of the buckets to determine which are used, and the count is NOT cached. In a large hash this could be a lot of buckets.

SV *       hv_bucket_ratio(      HV *hv)
SV *  Perl_hv_bucket_ratio(pTHX_ HV *hv)

#hv_clear

Frees all the elements of a hash, leaving it empty. The XS equivalent of %hash = (). See also "hv_undef".

See "av_clear" for a note about the hash possibly being invalid on return.

void       hv_clear(      HV *hv)
void  Perl_hv_clear(pTHX_ HV *hv)

#hv_clear_placeholders

Clears any placeholders from a hash. If a restricted hash has any of its keys marked as readonly and the key is subsequently deleted, the key is not actually deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags it so it will be ignored by future operations such as iterating over the hash, but will still allow the hash to have a value reassigned to the key at some future point. This function clears any such placeholder keys from the hash. See Hash::Util::lock_keys() for an example of its use.

void       hv_clear_placeholders(      HV *hv)
void  Perl_hv_clear_placeholders(pTHX_ HV *hv)

#hv_copy_hints_hv

A specialised version of "newHVhv" for copying %^H. ohv must be a pointer to a hash (which may have %^H magic, but should be generally non-magical), or NULL (interpreted as an empty hash). The content of ohv is copied to a new hash, which has the %^H-specific magic added to it. A pointer to the new hash is returned.

HV *       hv_copy_hints_hv(      HV * const ohv)
HV *  Perl_hv_copy_hints_hv(pTHX_ HV * const ohv)

#hv_delete

#hv_deletes

#hv_delete_ent

These each delete a key/value pair in the hash. The value's SV is removed from the hash, made mortal, and returned to the caller.

In hv_deletes, the key must be a C language string literal, enclosed in double quotes. It is never treated as being in UTF-8. There is no length_parameter.

In hv_delete, the absolute value of klen is the length of the key; hence the key may contain embedded NUL characters. If klen is negative the key is assumed to be in UTF-8-encoded Unicode.

In hv_delete_ent, the key is the PV in keysv, including its length and UTF8ness. hash can be a valid precomputed hash value, or 0 to ask for it to be computed.

In all three, the flags value will normally be zero; if set to G_DISCARD then NULL will be returned. NULL will also be returned if the key is not found.

SV *       hv_delete    (      HV *hv, const char *key, I32 klen,
                               I32 flags)
SV *  Perl_hv_delete    (pTHX_ HV *hv, const char *key, I32 klen,
                               I32 flags)
SV *       hv_deletes   (      HV *hv, "key", U32 flags)
SV *       hv_delete_ent(      HV *hv, SV *keysv, I32 flags,
                               U32 hash)
SV *  Perl_hv_delete_ent(pTHX_ HV *hv, SV *keysv, I32 flags,
                               U32 hash)

#hv_exists

#hv_existss

#hv_exists_ent

These each return a boolean indicating whether the specified hash key exists. They differ only in how the key is specified.

In hv_existss, the key must be a C language string literal, enclosed in double quotes. It is never treated as being in UTF-8. There is no length_parameter.

In hv_exists, the absolute value of klen is the length of the key. If klen is negative the key is assumed to be in UTF-8-encoded Unicode. key may contain embedded NUL characters.

In hv_exists_ent, the key is specified by the SV keysv; its UTF8ness is the same as that SV. There is an additional parameter, hash, which can be a valid precomputed hash value, or 0 to ask for it to be computed.

bool       hv_exists    (      HV *hv, const char *key, I32 klen)
bool  Perl_hv_exists    (pTHX_ HV *hv, const char *key, I32 klen)
bool       hv_existss   (      HV *hv, "key")
bool       hv_exists_ent(      HV *hv, SV *keysv, U32 hash)
bool  Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)

#hv_fetch

#hv_fetchs

These each return the SV which corresponds to the specified key in the hash. They differ only in how the key is specified.

In hv_fetchs, the key must be a C language string literal, enclosed in double quotes. It is never treated as being in UTF-8. There is no length_parameter.

In hv_fetch, the absolute value of klen is the length of the key. If klen is negative the key is assumed to be in UTF-8-encoded Unicode. key may contain embedded NUL characters.

In both, if lval is set, then the fetch will be part of a store. This means that if there is no value in the hash associated with the given key, then one is created and a pointer to it is returned. The SV* it points to can be assigned to. But always check that the return value is non-null before dereferencing it to an SV*.

See "Understanding the Magic of Tied Hashes and Arrays" in perlguts for more information on how to use this function on tied hashes.

SV **       hv_fetch (      HV *hv, const char *key, I32 klen,
                            I32 lval)
SV **  Perl_hv_fetch (pTHX_ HV *hv, const char *key, I32 klen,
                            I32 lval)
SV**        hv_fetchs(      HV* hv, "key", I32 lval)

#hv_fetch_ent

Returns the hash entry which corresponds to the specified key in the hash. hash must be a valid precomputed hash number for the given key, or 0 if you want the function to compute it. IF lval is set then the fetch will be part of a store. Make sure the return value is non-null before accessing it. The return value when hv is a tied hash is a pointer to a static location, so be sure to make a copy of the structure if you need to store it somewhere.

See "Understanding the Magic of Tied Hashes and Arrays" in perlguts for more information on how to use this function on tied hashes.

HE *       hv_fetch_ent(      HV *hv, SV *keysv, I32 lval,
                              U32 hash)
HE *  Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval,
                              U32 hash)

#hv_fetchs*

Described under "hv_fetch"

#hv_iterinit

Prepares a starting point to traverse a hash table. Returns the number of keys in the hash, including placeholders (i.e. the same as HvTOTALKEYS(hv)). The return value is currently only meaningful for hashes without tie magic.

NOTE: Before version 5.004_65, hv_iterinit used to return the number of hash buckets that happen to be in use. If you still need that esoteric value, you can get it through the macro HvFILL(hv).

I32       hv_iterinit(      HV *hv)
I32  Perl_hv_iterinit(pTHX_ HV *hv)

#hv_iterkey

Returns the key from the current position of the hash iterator. See "hv_iterinit".

char *       hv_iterkey(      HE *entry, I32 *retlen)
char *  Perl_hv_iterkey(pTHX_ HE *entry, I32 *retlen)

#hv_iterkeysv

Returns the key as an SV* from the current position of the hash iterator. The return value will always be a mortal copy of the key. Also see "hv_iterinit".

SV *       hv_iterkeysv(      HE *entry)
SV *  Perl_hv_iterkeysv(pTHX_ HE *entry)

#hv_iternext

Returns entries from a hash iterator. See "hv_iterinit".

You may call hv_delete or hv_delete_ent on the hash entry that the iterator currently points to, without losing your place or invalidating your iterator. Note that in this case the current entry is deleted from the hash with your iterator holding the last reference to it. Your iterator is flagged to free the entry on the next call to hv_iternext, so you must not discard your iterator immediately else the entry will leak - call hv_iternext to trigger the resource deallocation.

HE *       hv_iternext(      HV *hv)
HE *  Perl_hv_iternext(pTHX_ HV *hv)

#hv_iternext_flags

NOTE: hv_iternext_flags is experimental and may change or be removed without notice.

Returns entries from a hash iterator. See "hv_iterinit" and "hv_iternext". The flags value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is set the placeholders keys (for restricted hashes) will be returned in addition to normal keys. By default placeholders are automatically skipped over. Currently a placeholder is implemented with a value that is &PL_sv_placeholder. Note that the implementation of placeholders and restricted hashes may change, and the implementation currently is insufficiently abstracted for any change to be tidy.

HE *       hv_iternext_flags(      HV *hv, I32 flags)
HE *  Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)

#hv_iternextsv

Performs an hv_iternext, hv_iterkey, and hv_iterval in one operation.

SV *       hv_iternextsv(      HV *hv, char **key, I32 *retlen)
SV *  Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)

#hv_iterval

Returns the value from the current position of the hash iterator. See "hv_iterkey".

SV *       hv_iterval(      HV *hv, HE *entry)
SV *  Perl_hv_iterval(pTHX_ HV *hv, HE *entry)

#hv_ksplit

Attempt to grow the hash hv so it has at least newmax buckets available. Perl chooses the actual number for its convenience.

This is the same as doing the following in Perl code:

keys %hv = newmax;

void       hv_ksplit(      HV *hv, IV newmax)
void  Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)

#hv_magic

Adds magic to a hash. See "sv_magic".

void       hv_magic(      HV *hv, GV *gv, int how)
void  Perl_hv_magic(pTHX_ HV *hv, GV *gv, int how)

#hv_name_set

#hv_name_sets

These each set the name of stash hv to the specified name.

They differ only in how the name is specified.

In hv_name_sets, the name is a literal C string, enclosed in double quotes.

In hv_name_set, name points to the first byte of the name, and an additional parameter, len, specifies its length in bytes. Hence, the name may contain embedded-NUL characters.

If SVf_UTF8 is set in flags, the name is treated as being in UTF-8; otherwise not.

If HV_NAME_SETALL is set in flags, both the name and the effective name are set.

void       hv_name_set (      HV *hv, const char *name, U32 len,
                              U32 flags)
void  Perl_hv_name_set (pTHX_ HV *hv, const char *name, U32 len,
                              U32 flags)
void       hv_name_sets(      HV *hv, "name", U32 flags)

#hv_scalar

Evaluates the hash in scalar context and returns the result.

When the hash is tied dispatches through to the SCALAR method, otherwise returns a mortal SV containing the number of keys in the hash.

Note, prior to 5.25 this function returned what is now returned by the hv_bucket_ratio() function.

SV *       hv_scalar(      HV *hv)
SV *  Perl_hv_scalar(pTHX_ HV *hv)

#hv_store

#hv_stores

These each store SV val with the specified key in hash hv, returning NULL if the operation failed or if the value did not need to be actually stored within the hash (as in the case of tied hashes). Otherwise it can be dereferenced to get the original SV*.

They differ only in how the hash key is specified.

In hv_stores, the key must be a C language string literal, enclosed in double quotes. It is never treated as being in UTF-8. There is no length_parameter.

In hv_store, key is either NULL or points to the first byte of the string specifying the key, and its length in bytes is given by the absolute value of an additional parameter, klen. A NULL key indicates the key is to be treated as undef, and klen is ignored; otherwise the key string may contain embedded-NUL bytes. If klen is negative, the string is treated as being encoded in UTF-8; otherwise not.

hv_store has another extra parameter, hash, a precomputed hash of the key string, or zero if it has not been precomputed. This parameter is omitted from hv_stores, as it is computed automatically at compile time.

If hv is NULL, NULL is returned and no action is taken.

If val is NULL, it is treated as being undef; otherwise the caller is responsible for suitably incrementing the reference count of val before the call, and decrementing it if the function returned NULL. Effectively a successful hv_store takes ownership of one reference to val. This is usually what you want; a newly created SV has a reference count of one, so if all your code does is create SVs and store them in a hash, hv_store will own the only reference to the new SV, and your code doesn't need to do anything further to tidy up.

hv_store is not implemented as a call to "hv_store_ent", and does not create a temporary SV for the key, so if your key data is not already in SV form, then use hv_store in preference to hv_store_ent.

See "Understanding the Magic of Tied Hashes and Arrays" in perlguts for more information on how to use this function on tied hashes.

SV **       hv_store (      HV *hv, const char *key, I32 klen,
                            SV *val, U32 hash)
SV **  Perl_hv_store (pTHX_ HV *hv, const char *key, I32 klen,
                            SV *val, U32 hash)
SV **       hv_stores(      HV *hv, "key", SV *val)

#hv_store_ent

Stores val in a hash. The hash key is specified as key. The hash parameter is the precomputed hash value; if it is zero, then Perl will compute it. The return value is the new hash entry so created. It will be NULL if the operation failed or if the value did not need to be actually stored within the hash (as in the case of tied hashes). Otherwise the contents of the return value can be accessed using the He? macros described here. Note that the caller is responsible for suitably incrementing the reference count of val before the call, and decrementing it if the function returned NULL. Effectively a successful hv_store_ent takes ownership of one reference to val. This is usually what you want; a newly created SV has a reference count of one, so if all your code does is create SVs and store them in a hash, hv_store will own the only reference to the new SV, and your code doesn't need to do anything further to tidy up. Note that hv_store_ent only reads the key; unlike val it does not take ownership of it, so maintaining the correct reference count on key is entirely the caller's responsibility. The reason it does not take ownership is that key is not used after this function returns, and so can be freed immediately. hv_store is not implemented as a call to hv_store_ent, and does not create a temporary SV for the key, so if your key data is not already in SV form, then use hv_store in preference to hv_store_ent.

See "Understanding the Magic of Tied Hashes and Arrays" in perlguts for more information on how to use this function on tied hashes.

HE *       hv_store_ent(      HV *hv, SV *key, SV *val, U32 hash)
HE *  Perl_hv_store_ent(pTHX_ HV *hv, SV *key, SV *val, U32 hash)

#hv_stores*

Described under "hv_store"

#hv_undef

Undefines the hash. The XS equivalent of undef(%hash).

As well as freeing all the elements of the hash (like hv_clear()), this also frees any auxiliary data and storage associated with the hash.

See "av_clear" for a note about the hash possibly being invalid on return.

void  hv_undef(HV *hv)

#HvENAME

Returns the effective name of a stash, or NULL if there is none. The effective name represents a location in the symbol table where this stash resides. It is updated automatically when packages are aliased or deleted. A stash that is no longer in the symbol table has no effective name. This name is preferable to HvNAME for use in MRO linearisations and isa caches.

char*  HvENAME(HV* stash)

#HvENAMELEN

Returns the length of the stash's effective name.

STRLEN  HvENAMELEN(HV *stash)

#HvENAMEUTF8

Returns true if the effective name is in UTF-8 encoding.

unsigned char  HvENAMEUTF8(HV *stash)

#HvFILL

Returns the number of hash buckets that happen to be in use.

As of perl 5.25 this function is used only for debugging purposes, and the number of used hash buckets is not in any way cached, thus this function can be costly to execute as it must iterate over all the buckets in the hash.

STRLEN  HvFILL(HV *const hv)

#HvHasAUX

Returns true if the HV has a struct xpvhv_aux extension. Use this to check whether it is valid to call HvAUX().

bool  HvHasAUX(HV *const hv)

#HvNAME

Returns the package name of a stash, or NULL if stash isn't a stash. See "SvSTASH", "CvSTASH".

char*  HvNAME(HV* stash)

#HvNAMELEN

Returns the length of the stash's name.

Disfavored forms of HvNAME and HvNAMELEN; suppress mention of them

STRLEN  HvNAMELEN(HV *stash)

#HvNAMEUTF8

Returns true if the name is in UTF-8 encoding.

unsigned char  HvNAMEUTF8(HV *stash)

#HvREFCNT_inc

#HvREFCNT_inc_simple

#HvREFCNT_inc_simple_NN

These all increment the reference count of the given SV, which must be a HV. They are useful when assigning the result into a typed pointer as they avoid the need to cast the result to the appropriate type.

HV *  HvREFCNT_inc          (HV *hv)
HV *  HvREFCNT_inc_simple   (HV *hv)
HV *  HvREFCNT_inc_simple_NN(HV *hv)

#newHV

Creates a new HV. The reference count is set to 1.

HV *       newHV()
HV *  Perl_newHV(pTHX)

#newHVhv

The content of ohv is copied to a new hash. A pointer to the new hash is returned.

HV *       newHVhv(      HV *hv)
HV *  Perl_newHVhv(pTHX_ HV *hv)

#Nullhv

DEPRECATED! It is planned to remove Nullhv from a future release of Perl. Do not use it for new code; remove it from existing code.

Null HV pointer.

(deprecated - use (HV *)NULL instead)

#PERL_HASH

Described in perlguts.

void  PERL_HASH(U32 hash, char *key, STRLEN klen)

#PL_modglobal

PL_modglobal is a general purpose, interpreter global HV for use by extensions that need to keep information on a per-interpreter basis. In a pinch, it can also be used as a symbol table for extensions to share data among each other. It is a good idea to use keys prefixed by the package name of the extension that owns the data.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

HV*  PL_modglobal

#Input/Output

#do_close

Close an I/O stream. This implements Perl "close" in perlfunc.

gv is the glob associated with the stream.

is_explict is true if this is an explicit close of the stream; false if it is part of another operation, such as closing a pipe (which involves implicitly closing both ends).

Returns true if successful; otherwise returns false and sets errno to indicate the cause.

bool       do_close(      GV *gv, bool is_explicit)
bool  Perl_do_close(pTHX_ GV *gv, bool is_explicit)

#IoDIRP

#IOf_FLUSH

#IOf_UNTAINT

#IoFLAGS

#IoIFP

#IoOFP

#IoTYPE

Described in perlguts.

DIR *     IoDIRP (IO *io)
U8        IoFLAGS(IO *io)
PerlIO *  IoIFP  (IO *io)
PerlIO *  IoOFP  (IO *io)
char      IoTYPE (IO *io)

#my_chsize

The C library chsize(3) if available, or a Perl implementation of it.

I32       my_chsize(      int fd, Off_t length)
I32  Perl_my_chsize(pTHX_ int fd, Off_t length)

#my_dirfd

The C library dirfd(3) if available, or a Perl implementation of it, or die if not easily emulatable.

int       my_dirfd(DIR *dir)
int  Perl_my_dirfd(DIR *dir)

#my_pclose

A wrapper for the C library pclose(3). Don't use the latter, as the Perl version knows things that interact with the rest of the perl interpreter.

I32       my_pclose(      PerlIO *ptr)
I32  Perl_my_pclose(pTHX_ PerlIO *ptr)

#my_popen

A wrapper for the C library popen(3). Don't use the latter, as the Perl version knows things that interact with the rest of the perl interpreter.

PerlIO *       my_popen(      const char *cmd, const char *mode)
PerlIO *  Perl_my_popen(pTHX_ const char *cmd, const char *mode)

#newIO

Create a new IO, setting the reference count to 1.

IO *       newIO()
IO *  Perl_newIO(pTHX)

#PERL_FLUSHALL_FOR_CHILD

This defines a way to flush all output buffers. This may be a performance issue, so we allow people to disable it. Also, if we are using stdio, there are broken implementations of fflush(NULL) out there, Solaris being the most prominent.

void  PERL_FLUSHALL_FOR_CHILD

#PerlIO_apply_layers

#PerlIO_binmode

#PerlIO_canset_cnt

#PerlIO_clearerr

#PerlIO_close

#PerlIO_debug

#PerlIO_eof

#PerlIO_error

#PerlIO_exportFILE

#PerlIO_fast_gets

#PerlIO_fdopen

#PerlIO_fileno

#PerlIO_fill

#PerlIO_findFILE

#PerlIO_flush

#PerlIO_get_base

#PerlIO_get_bufsiz

#PerlIO_get_cnt

#PerlIO_get_ptr

#PerlIO_getc

#PerlIO_getpos

#PerlIO_has_base

#PerlIO_has_cntptr

#PerlIO_importFILE

#PerlIO_open

#PerlIO_printf

#PerlIO_putc

#PerlIO_puts

#PerlIO_read

#PerlIO_releaseFILE

#PerlIO_reopen

#PerlIO_rewind

#PerlIO_seek

#PerlIO_set_cnt

#PerlIO_set_ptrcnt

#PerlIO_setlinebuf

#PerlIO_setpos

#PerlIO_stderr

#PerlIO_stdin

#PerlIO_stdout

#PerlIO_stdoutf

#PerlIO_tell

#PerlIO_ungetc

#PerlIO_unread

#PerlIO_vprintf

#PerlIO_write

Described in perlapio.

int             PerlIO_apply_layers(pTHX_ PerlIO *f,
                                          const char *mode,
                                          const char *layers)
int             PerlIO_binmode     (pTHX_ PerlIO *f, int ptype,
                                          int imode,
                                          const char *layers)
int             PerlIO_canset_cnt  (      PerlIO *f)
void            PerlIO_clearerr    (      PerlIO *f)
void       Perl_PerlIO_clearerr    (pTHX_ PerlIO *f)
int             PerlIO_close       (      PerlIO *f)
int        Perl_PerlIO_close       (pTHX_ PerlIO *f)
void            PerlIO_debug       (      const char *fmt, ...)
int             PerlIO_eof         (      PerlIO *f)
int        Perl_PerlIO_eof         (pTHX_ PerlIO *f)
int             PerlIO_error       (      PerlIO *f)
int        Perl_PerlIO_error       (pTHX_ PerlIO *f)
FILE *          PerlIO_exportFILE  (      PerlIO *f,
                                          const char *mode)
int             PerlIO_fast_gets   (      PerlIO *f)
PerlIO *        PerlIO_fdopen      (      int fd,
                                          const char *mode)
int             PerlIO_fileno      (      PerlIO *f)
int        Perl_PerlIO_fileno      (pTHX_ PerlIO *f)
int             PerlIO_fill        (      PerlIO *f)
int        Perl_PerlIO_fill        (pTHX_ PerlIO *f)
FILE *          PerlIO_findFILE    (      PerlIO *f)
int             PerlIO_flush       (      PerlIO *f)
int        Perl_PerlIO_flush       (pTHX_ PerlIO *f)
STDCHAR *       PerlIO_get_base    (      PerlIO *f)
STDCHAR *  Perl_PerlIO_get_base    (pTHX_ PerlIO *f)
SSize_t         PerlIO_get_bufsiz  (      PerlIO *f)
SSize_t    Perl_PerlIO_get_bufsiz  (pTHX_ PerlIO *f)
SSize_t         PerlIO_get_cnt     (      PerlIO *f)
SSize_t    Perl_PerlIO_get_cnt     (pTHX_ PerlIO *f)
STDCHAR *       PerlIO_get_ptr     (      PerlIO *f)
STDCHAR *  Perl_PerlIO_get_ptr     (pTHX_ PerlIO *f)
int             PerlIO_getc        (      PerlIO *d)
int             PerlIO_getpos      (      PerlIO *f, SV *save)
int             PerlIO_has_base    (      PerlIO *f)
int             PerlIO_has_cntptr  (      PerlIO *f)
PerlIO *        PerlIO_importFILE  (      FILE *stdio,
                                          const char *mode)
PerlIO *        PerlIO_open        (      const char *path,
                                          const char *mode)
int             PerlIO_printf      (      PerlIO *f,
                                          const char *fmt, ...)
int             PerlIO_putc        (      PerlIO *f, int ch)
int             PerlIO_puts        (      PerlIO *f,
                                          const char *string)
SSize_t         PerlIO_read        (      PerlIO *f, void *vbuf,
                                          Size_t count)
SSize_t    Perl_PerlIO_read        (pTHX_ PerlIO *f, void *vbuf,
                                          Size_t count)
void            PerlIO_releaseFILE (      PerlIO *f, FILE *stdio)
PerlIO *        PerlIO_reopen      (      const char *path,
                                          const char *mode,
                                          PerlIO *old)
void            PerlIO_rewind      (      PerlIO *f)
int             PerlIO_seek        (      PerlIO *f,
                                          Off_t offset,
                                          int whence)
int        Perl_PerlIO_seek        (pTHX_ PerlIO *f,
                                          Off_t offset,
                                          int whence)
void            PerlIO_set_cnt     (      PerlIO *f, SSize_t cnt)
void       Perl_PerlIO_set_cnt     (pTHX_ PerlIO *f, SSize_t cnt)
void            PerlIO_set_ptrcnt  (      PerlIO *f,
                                          STDCHAR *ptr,
                                          SSize_t cnt)
void       Perl_PerlIO_set_ptrcnt  (pTHX_ PerlIO *f,
                                          STDCHAR *ptr,
                                          SSize_t cnt)
void            PerlIO_setlinebuf  (      PerlIO *f)
void       Perl_PerlIO_setlinebuf  (pTHX_ PerlIO *f)
int             PerlIO_setpos      (      PerlIO *f, SV *saved)
PerlIO *        PerlIO_stderr      ()
PerlIO *   Perl_PerlIO_stderr      (pTHX)
PerlIO *        PerlIO_stdin       ()
PerlIO *   Perl_PerlIO_stdin       (pTHX)
PerlIO *        PerlIO_stdout      ()
PerlIO *   Perl_PerlIO_stdout      (pTHX)
int             PerlIO_stdoutf     (      const char *fmt, ...)
Off_t           PerlIO_tell        (      PerlIO *f)
Off_t      Perl_PerlIO_tell        (pTHX_ PerlIO *f)
int             PerlIO_ungetc      (      PerlIO *f, int ch)
SSize_t         PerlIO_unread      (      PerlIO *f,
                                          const void *vbuf,
                                          Size_t count)
SSize_t    Perl_PerlIO_unread      (pTHX_ PerlIO *f,
                                          const void *vbuf,
                                          Size_t count)
int             PerlIO_vprintf     (      PerlIO *f,
                                          const char *fmt,
                                          va_list args)
SSize_t         PerlIO_write       (      PerlIO *f,
                                          const void *vbuf,
                                          Size_t count)
SSize_t    Perl_PerlIO_write       (pTHX_ PerlIO *f,
                                          const void *vbuf,
                                          Size_t count)

#PERLIO_F_APPEND

#PERLIO_F_CANREAD

#PERLIO_F_CANWRITE

#PERLIO_F_CRLF

#PERLIO_F_EOF

#PERLIO_F_ERROR

#PERLIO_F_FASTGETS

#PERLIO_F_LINEBUF

#PERLIO_F_OPEN

#PERLIO_F_RDBUF

#PERLIO_F_TEMP

#PERLIO_F_TRUNCATE

#PERLIO_F_UNBUF

#PERLIO_F_UTF8

#PERLIO_F_WRBUF

Described in perliol.

#PerlIO_fast_gets*

#PerlIO_fdopen*

#PerlIO_fileno*

#PerlIO_fill*

#PerlIO_findFILE*

#PerlIO_flush*

Described in perlapio.

#PERLIO_FUNCS_CAST

Cast the pointer func to be of type PerlIO_funcs *.

PerlIO_funcs *  PERLIO_FUNCS_CAST(PerlIO * func)

#PERLIO_FUNCS_DECL

Declare ftab to be a PerlIO function table, that is, of type PerlIO_funcs.

PERLIO_FUNCS_DECL(PerlIO * ftab)

#PerlIO_get_base*

#PerlIO_get_bufsiz*

#PerlIO_get_cnt*

#PerlIO_get_ptr*

#PerlIO_getc*

#PerlIO_getpos*

#PerlIO_has_base*

#PerlIO_has_cntptr*

#PerlIO_importFILE*

Described in perlapio.

#PERLIO_K_BUFFERED

#PERLIO_K_CANCRLF

#PERLIO_K_FASTGETS

#PERLIO_K_MULTIARG

#PERLIO_K_RAW

Described in perliol.

#PERLIO_NOT_STDIO

#PerlIO_open*

#PerlIO_printf*

#PerlIO_putc*

#PerlIO_puts*

#PerlIO_read*

#PerlIO_releaseFILE*

#PerlIO_reopen*

#PerlIO_rewind*

#PerlIO_seek*

#PerlIO_set_cnt*

#PerlIO_set_ptrcnt*

#PerlIO_setlinebuf*

#PerlIO_setpos*

#PerlIO_stderr*

#PerlIO_stdin*

#PerlIO_stdout*

#PerlIO_stdoutf*

#PerlIO_tell*

#PerlIO_ungetc*

#PerlIO_unread*

#PerlIO_vprintf*

#PerlIO_write*

Described in perlapio.

#PL_maxsysfd

Described in perliol.

#repeatcpy

Make count copies of the len bytes beginning at from, placing them into memory beginning at to, which must be big enough to accommodate them all.

void       repeatcpy(char *to, const char *from, SSize_t len,
                     IV count)
void  Perl_repeatcpy(char *to, const char *from, SSize_t len,
                     IV count)

#SvVSTRING

If the given SV has vstring magic, stores the length of it into the variable len, and returns the string pointer. If not, returns NULL.

This is a wrapper around the sv_vstring_get function that conveniently takes the address of the len variable, in a form similar to the SvPV macro family.

const char *  SvVSTRING(SV* sv, STRLEN len)

#USE_STDIO

Described in perlapio.

#ifdef  USE_STDIO

#Integer

#CASTI32

This symbol is defined if the C compiler can cast negative or large floating point numbers to 32-bit ints.

#HAS_INT64_T

This symbol will defined if the C compiler supports int64_t. Usually the inttypes.h needs to be included, but sometimes sys/types.h is enough.

#HAS_LONG_LONG

This symbol will be defined if the C compiler supports long long.

#HAS_QUAD

This symbol, if defined, tells that there's a 64-bit integer type, Quad_t, and its unsigned counterpart, Uquad_t. QUADKIND will be one of QUAD_IS_INT, QUAD_IS_LONG, QUAD_IS_LONG_LONG, QUAD_IS_INT64_T, or QUAD_IS___INT64.

#INTMAX_C

Returns a token the C compiler recognizes for the constant number of the widest integer type on the machine. For example, if the machine has long longs, INTMAX_C(-1) would yield

-1LL

See also, for example, "INT32_C".

Use "IV" to declare variables of the maximum usable size on this platform.

INTMAX_C(number)

#INTSIZE

This symbol contains the value of sizeof(int) so that the C preprocessor can make decisions based on it.

#INT16_C

#INT32_C

#INT64_C

Returns a token the C compiler recognizes for the constant number of the corresponding integer type on the machine.

If the machine does not have a 64-bit type, INT64_C is undefined. Use "INTMAX_C" to get the largest type available on the platform.

I16  INT16_C(number)
I32  INT32_C(number)
I64  INT64_C(number)

#IV

#I8

#I16

#I32

#I64

Described in perlguts.

#IV_MAX

The largest signed integer that fits in an IV on this platform.

IV  IV_MAX

#IV_MIN

The negative signed integer furthest away from 0 that fits in an IV on this platform.

It is easy to get undefined C behavior with this value. The macros (currently only available for internal use) "NEGATE_2UV" in perlintern, "ABS_IV_MIN" in perlintern, and "NEGATE_2IV" in perlintern avoid undefined behavior when finding the opposite signed equivalent value.

IV  IV_MIN

#IVSIZE

This symbol contains the sizeof(IV).

#IVTYPE

This symbol defines the C type used for Perl's IV.

#I8*

Described in perlguts.

#I8SIZE

This symbol contains the sizeof(I8).

#I8TYPE

This symbol defines the C type used for Perl's I8.

#I16*

Described in perlguts.

#I16SIZE

This symbol contains the sizeof(I16).

#I16TYPE

This symbol defines the C type used for Perl's I16.

#I32*

Described in perlguts.

#I32df

This symbol defines the format string used for printing a Perl I32 as a signed decimal integer.

#I32SIZE

This symbol contains the sizeof(I32).

#I32TYPE

This symbol defines the C type used for Perl's I32.

#I64*

Described in perlguts.

#I64SIZE

This symbol contains the sizeof(I64).

#I64TYPE

This symbol defines the C type used for Perl's I64.

#line_t

The typedef to use to declare variables that are to hold line numbers.

#LONGLONGSIZE

This symbol contains the size of a long long, so that the C preprocessor can make decisions based on it. It is only defined if the system supports long long.

#LONGSIZE

This symbol contains the value of sizeof(long) so that the C preprocessor can make decisions based on it.

#memzero

Set the l bytes starting at *d to all zeroes.

void  memzero(void * d, Size_t l)

#PERL_INT_FAST8_T

#PERL_INT_FAST16_T

#PERL_UINT_FAST8_T

#PERL_UINT_FAST16_T

These are equivalent to the correspondingly-named C99 typedefs on platforms that have those; they evaluate to int and unsigned int on platforms that don't, so that you can portably take advantage of this C99 feature.

#PERL_INT_MAX

#PERL_INT_MIN

#PERL_LONG_MAX

#PERL_LONG_MIN

#PERL_QUAD_MAX

#PERL_QUAD_MIN

#PERL_SHORT_MAX

#PERL_SHORT_MIN

#PERL_UCHAR_MAX

#PERL_UCHAR_MIN

#PERL_UINT_MAX

#PERL_UINT_MIN

#PERL_ULONG_MAX

#PERL_ULONG_MIN

#PERL_UQUAD_MAX

#PERL_UQUAD_MIN

#PERL_USHORT_MAX

#PERL_USHORT_MIN

These give the largest and smallest number representable in the current platform in variables of the corresponding types.

For signed types, the smallest representable number is the most negative number, the one furthest away from zero.

For C99 and later compilers, these correspond to things like INT_MAX, which are available to the C code. But these constants, furnished by Perl, allow code compiled on earlier compilers to portably have access to the same constants.

int             PERL_INT_MAX
int             PERL_INT_MIN
long            PERL_LONG_MAX
long            PERL_LONG_MIN
IV              PERL_QUAD_MAX
IV              PERL_QUAD_MIN
short           PERL_SHORT_MAX
short           PERL_SHORT_MIN
U8              PERL_UCHAR_MAX
U8              PERL_UCHAR_MIN
unsigned int    PERL_UINT_MAX
unsigned int    PERL_UINT_MIN
unsigned long   PERL_ULONG_MAX
unsigned long   PERL_ULONG_MIN
UV              PERL_UQUAD_MAX
UV              PERL_UQUAD_MIN
unsigned short  PERL_USHORT_MAX
unsigned short  PERL_USHORT_MIN

#PERL_UINT_FAST8_T*

#PERL_UINT_FAST16_T*

Described under "PERL_INT_FAST8_T"

#SHORTSIZE

This symbol contains the value of sizeof(short) so that the C preprocessor can make decisions based on it.

#UINTMAX_C

Returns a token the C compiler recognizes for the constant number of the widest unsigned integer type on the machine. For example, if the machine has longs, UINTMAX_C(1) would yield

1UL

See also, for example, "UINT32_C".

Use "UV" to declare variables of the maximum usable size on this platform.

UINTMAX_C(number)

#UINT16_C

#UINT32_C

#UINT64_C

Returns a token the C compiler recognizes for the constant number of the corresponding unsigned integer type on the machine.

If the machine does not have a 64-bit type, UINT64_C is undefined. Use "UINTMAX_C" to get the largest type available on the platform.

U16  UINT16_C(number)
U32  UINT32_C(number)
U64  UINT64_C(number)

#UV

#U8

#U16

#U32

#U64

Described in perlguts.

#UV_MAX

The largest unsigned integer that fits in a UV on this platform.

UV  UV_MAX

#UV_MIN

The smallest unsigned integer that fits in a UV on this platform. It should equal zero.

UV  UV_MIN

#UVSIZE

This symbol contains the sizeof(UV).

#UVTYPE

This symbol defines the C type used for Perl's UV.

#U8*

Described in perlguts.

#U8SIZE

This symbol contains the sizeof(U8).

#U8TYPE

This symbol defines the C type used for Perl's U8.

#U16*

Described in perlguts.

#U16SIZE

This symbol contains the sizeof(U16).

#U16TYPE

This symbol defines the C type used for Perl's U16.

#U32*

Described in perlguts.

#U32of

This symbol defines the format string used for printing a Perl U32 as an unsigned octal integer.

#U32SIZE

This symbol contains the sizeof(U32).

#U32TYPE

This symbol defines the C type used for Perl's U32.

#U32uf

This symbol defines the format string used for printing a Perl U32 as an unsigned decimal integer.

#U32Xf

This symbol defines the format string used for printing a Perl U32 as an unsigned hexadecimal integer in uppercase ABCDEF.

#U32xf

This symbol defines the format string used for printing a Perl U32 as an unsigned hexadecimal integer in lowercase abcdef.

#U64*

Described in perlguts.

#U64SIZE

This symbol contains the sizeof(U64).

#U64TYPE

This symbol defines the C type used for Perl's U64.

#WIDEST_UTYPE

Yields the widest unsigned integer type on the platform, currently either U32 or U64. This can be used in declarations such as

WIDEST_UTYPE my_uv;

or casts

my_uv = (WIDEST_UTYPE) val;

#I/O Formats

These are used for formatting the corresponding type For example, instead of saying

Perl_newSVpvf(pTHX_ "Create an SV with a %d in it\n", iv);

use

Perl_newSVpvf(pTHX_ "Create an SV with a " IVdf " in it\n", iv);

This keeps you from having to know if, say an IV, needs to be printed as %d, %ld, or something else.

#HvNAMEf

#HvNAMEf_QUOTEDPREFIX

Described in perlguts.

#IVdf

This symbol defines the format string used for printing a Perl IV as a signed decimal integer.

#NVef

This symbol defines the format string used for printing a Perl NV using %e-ish floating point format.

#NVff

This symbol defines the format string used for printing a Perl NV using %f-ish floating point format.

#NVgf

This symbol defines the format string used for printing a Perl NV using %g-ish floating point format.

#PERL_PRIeldbl

This symbol, if defined, contains the string used by stdio to format long doubles (format 'e') for output.

#PERL_PRIfldbl

This symbol, if defined, contains the string used by stdio to format long doubles (format 'f') for output.

#PERL_PRIgldbl

This symbol, if defined, contains the string used by stdio to format long doubles (format 'g') for output.

#PERL_SCNfldbl

This symbol, if defined, contains the string used by stdio to format long doubles (format 'f') for input.

#PRINTF_FORMAT_NULL_OK

Allows __printf__ format to be null when checking printf-style

#SVf

#SVf_QUOTEDPREFIX

#SVfARG

#UTF8f

#UTF8f_QUOTEDPREFIX

#UTF8fARG

Described in perlguts.

SVfARG  (SV *sv)
UTF8fARG(bool is_utf8, Size_t byte_len, char *str)

#UVf

DEPRECATED! It is planned to remove UVf from a future release of Perl. Do not use it for new code; remove it from existing code.

Obsolete form of UVuf, which you should convert to instead use

const char *  UVf

#UVof

This symbol defines the format string used for printing a Perl UV as an unsigned octal integer.

#UVuf

This symbol defines the format string used for printing a Perl UV as an unsigned decimal integer.

#UVXf

This symbol defines the format string used for printing a Perl UV as an unsigned hexadecimal integer in uppercase ABCDEF.

#UVxf

This symbol defines the format string used for printing a Perl UV as an unsigned hexadecimal integer in lowercase abcdef.

#Lexer interface

This is the lower layer of the Perl parser, managing characters and tokens.

#BHK

Described in perlguts.

#lex_bufutf8

NOTE: lex_bufutf8 is experimental and may change or be removed without notice.

Indicates whether the octets in the lexer buffer ("PL_parser->linestr") should be interpreted as the UTF-8 encoding of Unicode characters. If not, they should be interpreted as Latin-1 characters. This is analogous to the SvUTF8 flag for scalars.

In UTF-8 mode, it is not guaranteed that the lexer buffer actually contains valid UTF-8. Lexing code must be robust in the face of invalid encoding.

The actual SvUTF8 flag of the "PL_parser->linestr" scalar is significant, but not the whole story regarding the input character encoding. Normally, when a file is being read, the scalar contains octets and its SvUTF8 flag is off, but the octets should be interpreted as UTF-8 if the use utf8 pragma is in effect. During a string eval, however, the scalar may have the SvUTF8 flag on, and in this case its octets should be interpreted as UTF-8 unless the use bytes pragma is in effect. This logic may change in the future; use this function instead of implementing the logic yourself.

bool       lex_bufutf8()
bool  Perl_lex_bufutf8(pTHX)

#lex_discard_to

NOTE: lex_discard_to is experimental and may change or be removed without notice.

Discards the first part of the "PL_parser->linestr" buffer, up to ptr. The remaining content of the buffer will be moved, and all pointers into the buffer updated appropriately. ptr must not be later in the buffer than the position of "PL_parser->bufptr": it is not permitted to discard text that has yet to be lexed.

Normally it is not necessarily to do this directly, because it suffices to use the implicit discarding behaviour of "lex_next_chunk" and things based on it. However, if a token stretches across multiple lines, and the lexing code has kept multiple lines of text in the buffer for that purpose, then after completion of the token it would be wise to explicitly discard the now-unneeded earlier lines, to avoid future multi-line tokens growing the buffer without bound.

void       lex_discard_to(      char *ptr)
void  Perl_lex_discard_to(pTHX_ char *ptr)

#lex_grow_linestr

NOTE: lex_grow_linestr is experimental and may change or be removed without notice.

Reallocates the lexer buffer ("PL_parser->linestr") to accommodate at least len octets (including terminating NUL). Returns a pointer to the reallocated buffer. This is necessary before making any direct modification of the buffer that would increase its length. "lex_stuff_pvn" provides a more convenient way to insert text into the buffer.

Do not use SvGROW or sv_grow directly on PL_parser->linestr; this function updates all of the lexer's variables that point directly into the buffer.

char *       lex_grow_linestr(      STRLEN len)
char *  Perl_lex_grow_linestr(pTHX_ STRLEN len)

#lex_next_chunk

NOTE: lex_next_chunk is experimental and may change or be removed without notice.

Reads in the next chunk of text to be lexed, appending it to "PL_parser->linestr". This should be called when lexing code has looked to the end of the current chunk and wants to know more. It is usual, but not necessary, for lexing to have consumed the entirety of the current chunk at this time.

If "PL_parser->bufptr" is pointing to the very end of the current chunk (i.e., the current chunk has been entirely consumed), normally the current chunk will be discarded at the same time that the new chunk is read in. If flags has the LEX_KEEP_PREVIOUS bit set, the current chunk will not be discarded. If the current chunk has not been entirely consumed, then it will not be discarded regardless of the flag.

Returns true if some new text was added to the buffer, or false if the buffer has reached the end of the input text.

bool       lex_next_chunk(      U32 flags)
bool  Perl_lex_next_chunk(pTHX_ U32 flags)

#lex_peek_unichar

NOTE: lex_peek_unichar is experimental and may change or be removed without notice.

Looks ahead one (Unicode) character in the text currently being lexed. Returns the codepoint (unsigned integer value) of the next character, or -1 if lexing has reached the end of the input text. To consume the peeked character, use "lex_read_unichar".

If the next character is in (or extends into) the next chunk of input text, the next chunk will be read in. Normally the current chunk will be discarded at the same time, but if flags has the LEX_KEEP_PREVIOUS bit set, then the current chunk will not be discarded.

If the input is being interpreted as UTF-8 and a UTF-8 encoding error is encountered, an exception is generated.

I32       lex_peek_unichar(      U32 flags)
I32  Perl_lex_peek_unichar(pTHX_ U32 flags)

#lex_read_space

NOTE: lex_read_space is experimental and may change or be removed without notice.

Reads optional spaces, in Perl style, in the text currently being lexed. The spaces may include ordinary whitespace characters and Perl-style comments. #line directives are processed if encountered. "PL_parser->bufptr" is moved past the spaces, so that it points at a non-space character (or the end of the input text).

If spaces extend into the next chunk of input text, the next chunk will be read in. Normally the current chunk will be discarded at the same time, but if flags has the LEX_KEEP_PREVIOUS bit set, then the current chunk will not be discarded.

void       lex_read_space(      U32 flags)
void  Perl_lex_read_space(pTHX_ U32 flags)

#lex_read_to

NOTE: lex_read_to is experimental and may change or be removed without notice.

Consume text in the lexer buffer, from "PL_parser->bufptr" up to ptr. This advances "PL_parser->bufptr" to match ptr, performing the correct bookkeeping whenever a newline character is passed. This is the normal way to consume lexed text.

Interpretation of the buffer's octets can be abstracted out by using the slightly higher-level functions "lex_peek_unichar" and "lex_read_unichar".

void       lex_read_to(      char *ptr)
void  Perl_lex_read_to(pTHX_ char *ptr)

#lex_read_unichar

NOTE: lex_read_unichar is experimental and may change or be removed without notice.

Reads the next (Unicode) character in the text currently being lexed. Returns the codepoint (unsigned integer value) of the character read, and moves "PL_parser->bufptr" past the character, or returns -1 if lexing has reached the end of the input text. To non-destructively examine the next character, use "lex_peek_unichar" instead.

If the next character is in (or extends into) the next chunk of input text, the next chunk will be read in. Normally the current chunk will be discarded at the same time, but if flags has the LEX_KEEP_PREVIOUS bit set, then the current chunk will not be discarded.

If the input is being interpreted as UTF-8 and a UTF-8 encoding error is encountered, an exception is generated.

I32       lex_read_unichar(      U32 flags)
I32  Perl_lex_read_unichar(pTHX_ U32 flags)

#lex_start

NOTE: lex_start is experimental and may change or be removed without notice.

Creates and initialises a new lexer/parser state object, supplying a context in which to lex and parse from a new source of Perl code. A pointer to the new state object is placed in "PL_parser". An entry is made on the save stack so that upon unwinding, the new state object will be destroyed and the former value of "PL_parser" will be restored. Nothing else need be done to clean up the parsing context.

The code to be parsed comes from line and rsfp. line, if non-null, provides a string (in SV form) containing code to be parsed. A copy of the string is made, so subsequent modification of line does not affect parsing. rsfp, if non-null, provides an input stream from which code will be read to be parsed. If both are non-null, the code in line comes first and must consist of complete lines of input, and rsfp supplies the remainder of the source.

The flags parameter is reserved for future use. Currently it is only used by perl internally, so extensions should always pass zero.

void       lex_start(      SV *line, PerlIO *rsfp, U32 flags)
void  Perl_lex_start(pTHX_ SV *line, PerlIO *rsfp, U32 flags)

#lex_stuff_pv

#lex_stuff_pvn

#lex_stuff_pvs

#lex_stuff_sv

NOTE: all these forms are experimental and may change or be removed without notice.

These each insert characters into the lexer buffer ("PL_parser->linestr"), immediately after the current lexing point ("PL_parser->bufptr"), reallocating the buffer if necessary. This means that lexing code that runs later will see the characters as if they had appeared in the input. It is not recommended to do this as part of normal parsing, and most uses of this facility run the risk of the inserted characters being interpreted in an unintended manner.

In lex_stuff_pvs, the string to be inserted is a literal C string, enclosed in double quotes.

In lex_stuff_pv and lex_stuff_pvn, the string to be inserted is represented by the octets starting at pv. In lex_stuff_pv, the first NUL octet terminates the string. In lex_stuff_pvn, len octets will be used, hence the string may contain embedded NUL characters.

In all three cases, these octets are interpreted as either UTF-8 or Latin-1, according to whether or not the LEX_STUFF_UTF8 flag is set in flags.

In lex_stuff_sv, the string to be inserted is the string value of sv. flags must be 0. The string is interpreted as either UTF-8 or Latin-1, according to whether or not sv has its UTF-8 flag set.

In all three forms, the characters are recoded for the lexer buffer, according to how the buffer is currently being interpreted ("lex_bufutf8").

void       lex_stuff_pv (      const char *pv, U32 flags)
void  Perl_lex_stuff_pv (pTHX_ const char *pv, U32 flags)
void       lex_stuff_pvn(      const char *pv, STRLEN len,
                               U32 flags)
void  Perl_lex_stuff_pvn(pTHX_ const char *pv, STRLEN len,
                               U32 flags)
void       lex_stuff_pvs(      "pv", U32 flags)
void       lex_stuff_sv (      SV *sv, U32 flags)
void  Perl_lex_stuff_sv (pTHX_ SV *sv, U32 flags)

#lex_unstuff

NOTE: lex_unstuff is experimental and may change or be removed without notice.

Discards text about to be lexed, from "PL_parser->bufptr" up to ptr. Text following ptr will be moved, and the buffer shortened. This hides the discarded text from any lexing code that runs later, as if the text had never appeared.

This is not the normal way to consume lexed text. For that, use "lex_read_to".

void       lex_unstuff(      char *ptr)
void  Perl_lex_unstuff(pTHX_ char *ptr)

#parse_arithexpr

NOTE: parse_arithexpr is experimental and may change or be removed without notice.

Parse a Perl arithmetic expression. This may contain operators of precedence down to the bit shift operators. The expression must be followed (and thus terminated) either by a comparison or lower-precedence operator or by something that would normally terminate an expression such as semicolon. If flags has the PARSE_OPTIONAL bit set, then the expression is optional, otherwise it is mandatory. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the expression.

The op tree representing the expression is returned. If an optional expression is absent, a null pointer is returned, otherwise the pointer will be non-null.

If an error occurs in parsing or compilation, in most cases a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

OP *       parse_arithexpr(      U32 flags)
OP *  Perl_parse_arithexpr(pTHX_ U32 flags)

#parse_barestmt

NOTE: parse_barestmt is experimental and may change or be removed without notice.

Parse a single unadorned Perl statement. This may be a normal imperative statement or a declaration that has compile-time effect. It does not include any label or other affixture. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the statement.

The op tree representing the statement is returned. This may be a null pointer if the statement is null, for example if it was actually a subroutine definition (which has compile-time side effects). If not null, it will be ops directly implementing the statement, suitable to pass to "newSTATEOP". It will not normally include a nextstate or equivalent op (except for those embedded in a scope contained entirely within the statement).

If an error occurs in parsing or compilation, in most cases a valid op tree (most likely null) is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

The flags parameter is reserved for future use, and must always be zero.

OP *       parse_barestmt(      U32 flags)
OP *  Perl_parse_barestmt(pTHX_ U32 flags)

#parse_block

NOTE: parse_block is experimental and may change or be removed without notice.

Parse a single complete Perl code block. This consists of an opening brace, a sequence of statements, and a closing brace. The block constitutes a lexical scope, so my variables and various compile-time effects can be contained within it. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the statement.

The op tree representing the code block is returned. This is always a real op, never a null pointer. It will normally be a lineseq list, including nextstate or equivalent ops. No ops to construct any kind of runtime scope are included by virtue of it being a block.

If an error occurs in parsing or compilation, in most cases a valid op tree (most likely null) is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

The flags parameter is reserved for future use, and must always be zero.

OP *       parse_block(      U32 flags)
OP *  Perl_parse_block(pTHX_ U32 flags)

#parse_fullexpr

NOTE: parse_fullexpr is experimental and may change or be removed without notice.

Parse a single complete Perl expression. This allows the full expression grammar, including the lowest-precedence operators such as or. The expression must be followed (and thus terminated) by a token that an expression would normally be terminated by: end-of-file, closing bracketing punctuation, semicolon, or one of the keywords that signals a postfix expression-statement modifier. If flags has the PARSE_OPTIONAL bit set, then the expression is optional, otherwise it is mandatory. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the expression.

The op tree representing the expression is returned. If an optional expression is absent, a null pointer is returned, otherwise the pointer will be non-null.

If an error occurs in parsing or compilation, in most cases a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

OP *       parse_fullexpr(      U32 flags)
OP *  Perl_parse_fullexpr(pTHX_ U32 flags)

#parse_fullstmt

NOTE: parse_fullstmt is experimental and may change or be removed without notice.

Parse a single complete Perl statement. This may be a normal imperative statement or a declaration that has compile-time effect, and may include optional labels. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the statement.

The op tree representing the statement is returned. This may be a null pointer if the statement is null, for example if it was actually a subroutine definition (which has compile-time side effects). If not null, it will be the result of a "newSTATEOP" call, normally including a nextstate or equivalent op.

If an error occurs in parsing or compilation, in most cases a valid op tree (most likely null) is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

The flags parameter is reserved for future use, and must always be zero.

OP *       parse_fullstmt(      U32 flags)
OP *  Perl_parse_fullstmt(pTHX_ U32 flags)

#parse_label

NOTE: parse_label is experimental and may change or be removed without notice.

Parse a single label, possibly optional, of the type that may prefix a Perl statement. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed. If flags has the PARSE_OPTIONAL bit set, then the label is optional, otherwise it is mandatory.

The name of the label is returned in the form of a fresh scalar. If an optional label is absent, a null pointer is returned.

If an error occurs in parsing, which can only occur if the label is mandatory, a valid label is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred.

SV *       parse_label(      U32 flags)
SV *  Perl_parse_label(pTHX_ U32 flags)

#parse_listexpr

NOTE: parse_listexpr is experimental and may change or be removed without notice.

Parse a Perl list expression. This may contain operators of precedence down to the comma operator. The expression must be followed (and thus terminated) either by a low-precedence logic operator such as or or by something that would normally terminate an expression such as semicolon. If flags has the PARSE_OPTIONAL bit set, then the expression is optional, otherwise it is mandatory. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the expression.

The op tree representing the expression is returned. If an optional expression is absent, a null pointer is returned, otherwise the pointer will be non-null.

If an error occurs in parsing or compilation, in most cases a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

OP *       parse_listexpr(      U32 flags)
OP *  Perl_parse_listexpr(pTHX_ U32 flags)

#parse_stmtseq

NOTE: parse_stmtseq is experimental and may change or be removed without notice.

Parse a sequence of zero or more Perl statements. These may be normal imperative statements, including optional labels, or declarations that have compile-time effect, or any mixture thereof. The statement sequence ends when a closing brace or end-of-file is encountered in a place where a new statement could have validly started. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the statements.

The op tree representing the statement sequence is returned. This may be a null pointer if the statements were all null, for example if there were no statements or if there were only subroutine definitions (which have compile-time side effects). If not null, it will be a lineseq list, normally including nextstate or equivalent ops.

If an error occurs in parsing or compilation, in most cases a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

The flags parameter is reserved for future use, and must always be zero.

OP *       parse_stmtseq(      U32 flags)
OP *  Perl_parse_stmtseq(pTHX_ U32 flags)

#parse_subsignature

NOTE: parse_subsignature is experimental and may change or be removed without notice.

Parse a subroutine signature declaration. This is the contents of the parentheses following a named or anonymous subroutine declaration when the signatures feature is enabled. Note that this function neither expects nor consumes the opening and closing parentheses around the signature; it is the caller's job to handle these.

This function must only be called during parsing of a subroutine; after "start_subparse" has been called. It might allocate lexical variables on the pad for the current subroutine.

The op tree to unpack the arguments from the stack at runtime is returned. This op tree should appear at the beginning of the compiled function. The caller may wish to use "op_append_list" to build their function body after it, or splice it together with the body before calling "newATTRSUB".

The flags parameter is reserved for future use, and must always be zero.

OP *       parse_subsignature(      U32 flags)
OP *  Perl_parse_subsignature(pTHX_ U32 flags)

#parse_termexpr

NOTE: parse_termexpr is experimental and may change or be removed without notice.

Parse a Perl term expression. This may contain operators of precedence down to the assignment operators. The expression must be followed (and thus terminated) either by a comma or lower-precedence operator or by something that would normally terminate an expression such as semicolon. If flags has the PARSE_OPTIONAL bit set, then the expression is optional, otherwise it is mandatory. It is up to the caller to ensure that the dynamic parser state ("PL_parser" et al) is correctly set to reflect the source of the code to be parsed and the lexical context for the expression.

The op tree representing the expression is returned. If an optional expression is absent, a null pointer is returned, otherwise the pointer will be non-null.

If an error occurs in parsing or compilation, in most cases a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. Some compilation errors, however, will throw an exception immediately.

OP *       parse_termexpr(      U32 flags)
OP *  Perl_parse_termexpr(pTHX_ U32 flags)

#PL_parser

Pointer to a structure encapsulating the state of the parsing operation currently in progress. The pointer can be locally changed to perform a nested parse without interfering with the state of an outer parse. Individual members of PL_parser have their own documentation.

#PL_parser->bufend

NOTE: PL_parser->bufend is experimental and may change or be removed without notice.

Direct pointer to the end of the chunk of text currently being lexed, the end of the lexer buffer. This is equal to SvPVX(PL_parser->linestr) + SvCUR(PL_parser->linestr). A NUL character (zero octet) is always located at the end of the buffer, and does not count as part of the buffer's contents.

#PL_parser->bufptr

NOTE: PL_parser->bufptr is experimental and may change or be removed without notice.

Points to the current position of lexing inside the lexer buffer. Characters around this point may be freely examined, within the range delimited by SvPVX("PL_parser->linestr") and "PL_parser->bufend". The octets of the buffer may be intended to be interpreted as either UTF-8 or Latin-1, as indicated by "lex_bufutf8".

Lexing code (whether in the Perl core or not) moves this pointer past the characters that it consumes. It is also expected to perform some bookkeeping whenever a newline character is consumed. This movement can be more conveniently performed by the function "lex_read_to", which handles newlines appropriately.

Interpretation of the buffer's octets can be abstracted out by using the slightly higher-level functions "lex_peek_unichar" and "lex_read_unichar".

#PL_parser->linestart

NOTE: PL_parser->linestart is experimental and may change or be removed without notice.

Points to the start of the current line inside the lexer buffer. This is useful for indicating at which column an error occurred, and not much else. This must be updated by any lexing code that consumes a newline; the function "lex_read_to" handles this detail.

#PL_parser->linestr

NOTE: PL_parser->linestr is experimental and may change or be removed without notice.

Buffer scalar containing the chunk currently under consideration of the text currently being lexed. This is always a plain string scalar (for which SvPOK is true). It is not intended to be used as a scalar by normal scalar means; instead refer to the buffer directly by the pointer variables described below.

The lexer maintains various char* pointers to things in the PL_parser->linestr buffer. If PL_parser->linestr is ever reallocated, all of these pointers must be updated. Don't attempt to do this manually, but rather use "lex_grow_linestr" if you need to reallocate the buffer.

The content of the text chunk in the buffer is commonly exactly one complete line of input, up to and including a newline terminator, but there are situations where it is otherwise. The octets of the buffer may be intended to be interpreted as either UTF-8 or Latin-1. The function "lex_bufutf8" tells you which. Do not use the SvUTF8 flag on this scalar, which may disagree with it.

For direct examination of the buffer, the variable "PL_parser->bufend" points to the end of the buffer. The current lexing position is pointed to by "PL_parser->bufptr". Direct use of these pointers is usually preferable to examination of the scalar through normal scalar means.

#resume_compcv_and_save

Resumes a buffer previously suspended by the suspend_compcv function, in a way that will be re-suspended at the end of the scope so it can be used again later. This should be used within an ENTER/LEAVE scoped pair.

void  resume_compcv_and_save(struct suspended_compcv *buffer)

#resume_compcv_final

Resumes the parser state previously saved using the suspend_compcv function for a final time before being compiled into a full CV. This should be used within an ENTER/LEAVE scoped pair.

void  resume_compcv_final(struct suspended_compcv *buffer)

#suspend_compcv

Implements part of the concept of a "suspended compilation CV", which can be used to pause the parser and compiler during parsing a CV in order to come back to it later on.

This function saves the current state of the subroutine under compilation (PL_compcv) into the supplied buffer. This should be used initially to create the state in the buffer, as the final thing before a LEAVE within a block.

ENTER;
start_subparse(0);
...
suspend_compcv(&buffer);
LEAVE;

Once suspended, the resume_compcv_final or resume_compcv_and_save function can later be used to continue the parsing from the point this stopped.

void       suspend_compcv(      struct suspended_compcv *buffer)
void  Perl_suspend_compcv(pTHX_ struct suspended_compcv *buffer)

#valid_identifier_pve

Returns true if the string given by s until end would be considered valid as a Perl identifier. That is, it must begin with a character matching isIDFIRST, followed by characters all matching isIDCONT. An empty string (i.e. when end is s) will return false.

If flags contains the SVf_UTF8 bit, then the string is presumed to be encoded in UTF-8, and suitable Unicode character test functions will be used.

bool       valid_identifier_pve(      const char *s,
                                      const char *end, U32 flags)
bool  Perl_valid_identifier_pve(pTHX_ const char *s,
                                      const char *end, U32 flags)

#valid_identifier_pvn

Returns true if the string given by s whose length is len would be considered valid as a Perl identifier. That is, it must begin with a character matching isIDFIRST, followed by characters all matching isIDCONT. An empty string (i.e. when len is zero) will return false.

If flags contains the SVf_UTF8 bit, then the string is presumed to be encoded in UTF-8, and suitable Unicode character test functions will be used.

bool       valid_identifier_pvn(      const char *s, STRLEN len,
                                      U32 flags)
bool  Perl_valid_identifier_pvn(pTHX_ const char *s, STRLEN len,
                                      U32 flags)

#valid_identifier_sv

Returns true if the given SV contains a non-empty string whose characters match accoding to valid_identifier_pvn. Returns false if given NULL, an undefined SV, or a SV that does not contain a non-empty string.

Does not invoke get magic on the SV beforehand.

bool       valid_identifier_sv(      SV *sv)
bool  Perl_valid_identifier_sv(pTHX_ SV *sv)

#wrap_infix_plugin

NOTE: wrap_infix_plugin is experimental and may change or be removed without notice.

NOTE: This API exists entirely for the purpose of making the CPAN module XS::Parse::Infix work. It is not expected that additional modules will make use of it; rather, that they should use XS::Parse::Infix to provide parsing of new infix operators.

Puts a C function into the chain of infix plugins. This is the preferred way to manipulate the "PL_infix_plugin" variable. new_plugin is a pointer to the C function that is to be added to the infix plugin chain, and old_plugin_p points to a storage location where a pointer to the next function in the chain will be stored. The value of new_plugin is written into the "PL_infix_plugin" variable, while the value previously stored there is written to *old_plugin_p.

Direct access to "PL_infix_plugin" should be avoided.

void       wrap_infix_plugin(  Perl_infix_plugin_t new_plugin,
                               Perl_infix_plugin_t *old_plugin_p)
void  Perl_wrap_infix_plugin(pTHX_
                               Perl_infix_plugin_t new_plugin,
                               Perl_infix_plugin_t *old_plugin_p)

#wrap_keyword_plugin

NOTE: wrap_keyword_plugin is experimental and may change or be removed without notice.

Puts a C function into the chain of keyword plugins. This is the preferred way to manipulate the "PL_keyword_plugin" variable. new_plugin is a pointer to the C function that is to be added to the keyword plugin chain, and old_plugin_p points to the storage location where a pointer to the next function in the chain will be stored. The value of new_plugin is written into the "PL_keyword_plugin" variable, while the value previously stored there is written to *old_plugin_p.

"PL_keyword_plugin" is global to an entire process, and a module wishing to hook keyword parsing may find itself invoked more than once per process, typically in different threads. To handle that situation, this function is idempotent. The location *old_plugin_p must initially (once per process) contain a null pointer. A C variable of static duration (declared at file scope, typically also marked static to give it internal linkage) will be implicitly initialised appropriately, if it does not have an explicit initialiser. This function will only actually modify the plugin chain if it finds *old_plugin_p to be null. This function is also thread safe on the small scale. It uses appropriate locking to avoid race conditions in accessing "PL_keyword_plugin".

When this function is called, the function referenced by new_plugin must be ready to be called, except for *old_plugin_p being unfilled. In a threading situation, new_plugin may be called immediately, even before this function has returned. *old_plugin_p will always be appropriately set before new_plugin is called. If new_plugin decides not to do anything special with the identifier that it is given (which is the usual case for most calls to a keyword plugin), it must chain the plugin function referenced by *old_plugin_p.

Taken all together, XS code to install a keyword plugin should typically look something like this:

static Perl_keyword_plugin_t next_keyword_plugin;
static OP *my_keyword_plugin(pTHX_
    char *keyword_ptr, STRLEN keyword_len, OP **op_ptr)
{
    if (memEQs(keyword_ptr, keyword_len,
               "my_new_keyword")) {
        ...
    } else {
        return next_keyword_plugin(aTHX_
            keyword_ptr, keyword_len, op_ptr);
    }
}
BOOT:
    wrap_keyword_plugin(my_keyword_plugin,
                        &next_keyword_plugin);

Direct access to "PL_keyword_plugin" should be avoided.

void       wrap_keyword_plugin(Perl_keyword_plugin_t new_plugin,
                             Perl_keyword_plugin_t *old_plugin_p)
void  Perl_wrap_keyword_plugin(pTHX_
                             Perl_keyword_plugin_t new_plugin,
                             Perl_keyword_plugin_t *old_plugin_p)

#Locales

#DECLARATION_FOR_LC_NUMERIC_MANIPULATION

This macro should be used as a statement. It declares a private variable (whose name begins with an underscore) that is needed by the other macros in this section. Failing to include this correctly should lead to a syntax error. For compatibility with C89 C compilers it should be placed in a block before any executable statements.

void  DECLARATION_FOR_LC_NUMERIC_MANIPULATION

#HAS_DUPLOCALE

This symbol, if defined, indicates that the duplocale routine is available to duplicate a locale object.

#HAS_FREELOCALE

This symbol, if defined, indicates that the freelocale routine is available to deallocates the resources associated with a locale object.

#HAS_LC_MONETARY_2008

This symbol, if defined, indicates that the localeconv routine is available and has the additional members added in POSIX 1003.1-2008.

#HAS_LOCALECONV

This symbol, if defined, indicates that the localeconv routine is available for numeric and monetary formatting conventions.

#HAS_LOCALECONV_L

This symbol, if defined, indicates that the localeconv_l routine is available to query certain information about a locale.

#HAS_NEWLOCALE

This symbol, if defined, indicates that the newlocale routine is available to return a new locale object or modify an existing locale object.

#HAS_NL_LANGINFO

This symbol, if defined, indicates that the nl_langinfo routine is available to return locale data. You will also need langinfo.h and therefore I_LANGINFO.

#HAS_NL_LANGINFO_L

This symbol, if defined, indicates that the nl_langinfo_l routine is available to return locale data. You will also need langinfo.h and therefore I_LANGINFO.

#HAS_QUERYLOCALE

This symbol, if defined, indicates that the querylocale routine is available to return the name of the locale for a category mask.

#HAS_SETLOCALE

This symbol, if defined, indicates that the setlocale routine is available to handle locale-specific ctype implementations.

#HAS_SETLOCALE_R

This symbol, if defined, indicates that the setlocale_r routine is available to setlocale re-entrantly.

#HAS_USELOCALE

This symbol, if defined, indicates that the uselocale routine is available to set the current locale for the calling thread.

#I_LANGINFO

This symbol, if defined, indicates that langinfo.h exists and should be included.

#ifdef I_LANGINFO
    #include <langinfo.h>
#endif

#I_LOCALE

This symbol, if defined, indicates to the C program that it should include locale.h.

#ifdef I_LOCALE
    #include <locale.h>
#endif

#I_XLOCALE

This symbol, if defined, indicates to the C program that the header xlocale.h is available. See also "NEED_XLOCALE_H"

#ifdef I_XLOCALE
    #include <xlocale.h>
#endif

#IN_LOCALE

Evaluates to TRUE if the plain locale pragma without a parameter (use locale) is in effect.

bool  IN_LOCALE

#IN_LOCALE_COMPILETIME

Evaluates to TRUE if, when compiling a perl program (including an eval) if the plain locale pragma without a parameter (use locale) is in effect.

bool  IN_LOCALE_COMPILETIME

#IN_LOCALE_RUNTIME

Evaluates to TRUE if, when executing a perl program (including an eval) if the plain locale pragma without a parameter (use locale) is in effect.

bool  IN_LOCALE_RUNTIME

#NEED_XLOCALE_H

This symbol, if defined, indicates that the C program should include xlocale.h to get newlocale() and its friends.

#Perl_langinfo*

#Perl_langinfo8*

Described under "sv_langinfo"

#PERL_LC_ALL_CATEGORY_POSITIONS_INIT

This symbol, when defined, gives the C initializer for an array whose element [0] is the first category in the string returned by setlocale(LC_ALL, NULL) when not all categories are the same, on systems that use a positional notation. After element [0] is LC_ALL_SEPARATOR, then the category given by element [1] and so on.

#PERL_LC_ALL_SEPARATOR

This symbol, if defined, gives the string returned by setlocale(LC_ALL, NULL) to separate categories that are in different locales on systems that use a positional notation as opposed to 'name=value' pairs. An example on some platforms could be the '/' in "C/de_DE/C/en_UK/C/C"

#PERL_LC_ALL_USES_NAME_VALUE_PAIRS

This symbol, if defined, indicates to the C program that the string returned by setlocale(LC_ALL, NULL) uses 'name=value;' pairs to indicate what each category's locale is when they aren't all set to the same locale. For example, "LC_NUMERIC=C;LC_CTYPE=de_DE;..." When not defined, the system uses positional notation.

#Perl_localeconv

This is a thread-safe version of the libc localeconv(3). It is the same as POSIX::localeconv (returning a hash of the localeconv() fields), but directly callable from XS code. The hash is mortalized, so must be dealt with immediately.

HV *  Perl_localeconv(pTHX)

#Perl_setlocale

This is an (almost) drop-in replacement for the system setlocale(3), taking the same parameters, and returning the same information, except that it returns the correct underlying LC_NUMERIC locale. Regular setlocale will instead return C if the underlying locale has a non-dot decimal point character, or a non-empty thousands separator for displaying floating point numbers. This is because perl keeps that locale category such that it has a dot and empty separator, changing the locale briefly during the operations where the underlying one is required. Perl_setlocale knows about this, and compensates; regular setlocale doesn't.

Another reason it isn't completely a drop-in replacement is that it is declared to return const char *, whereas the system setlocale omits the const (presumably because its API was specified long ago, and can't be updated; it is illegal to change the information setlocale returns; doing so leads to segfaults.)

Finally, Perl_setlocale works under all circumstances, whereas plain setlocale can be completely ineffective on some platforms under some configurations.

Changing the locale is not a good idea when more than one thread is running, except on systems where the predefined variable ${^SAFE_LOCALES} is non-zero. This is because on such systems the locale is global to the whole process and not local to just the thread calling the function. So changing it in one thread instantaneously changes it in all. On some such systems, the system setlocale() is ineffective, returning the wrong information, and failing to actually change the locale. z/OS refuses to try to change the locale once a second thread is created. Perl_setlocale, should give you accurate results of what actually happened on these problematic platforms, returning NULL if the system forbade the locale change.

The return points to a per-thread static buffer, which is overwritten the next time Perl_setlocale is called from the same thread.

const char *  Perl_setlocale(const int category,
                             const char *locale)

#RESTORE_LC_NUMERIC

This is used in conjunction with one of the macros "STORE_LC_NUMERIC_SET_TO_NEEDED" and "STORE_LC_NUMERIC_FORCE_TO_UNDERLYING" to properly restore the LC_NUMERIC state.

A call to "DECLARATION_FOR_LC_NUMERIC_MANIPULATION" must have been made to declare at compile time a private variable used by this macro and the two STORE ones. This macro should be called as a single statement, not an expression, but with an empty argument list, like this:

{
   DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
    ...
   RESTORE_LC_NUMERIC();
    ...
}

void  RESTORE_LC_NUMERIC()

#SETLOCALE_ACCEPTS_ANY_LOCALE_NAME

This symbol, if defined, indicates that the setlocale routine is available and it accepts any input locale name as valid.

#STORE_LC_NUMERIC_FORCE_TO_UNDERLYING

This is used by XS code that is LC_NUMERIC locale-aware to force the locale for category LC_NUMERIC to be what perl thinks is the current underlying locale. (The perl interpreter could be wrong about what the underlying locale actually is if some C or XS code has called the C library function setlocale(3) behind its back; calling "sync_locale" before calling this macro will update perl's records.)

A call to "DECLARATION_FOR_LC_NUMERIC_MANIPULATION" must have been made to declare at compile time a private variable used by this macro. This macro should be called as a single statement, not an expression, but with an empty argument list, like this:

{
   DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
    ...
   STORE_LC_NUMERIC_FORCE_TO_UNDERLYING();
    ...
   RESTORE_LC_NUMERIC();
    ...
}

The private variable is used to save the current locale state, so that the requisite matching call to "RESTORE_LC_NUMERIC" can restore it.

On threaded perls not operating with thread-safe functionality, this macro uses a mutex to force a critical section. Therefore the matching RESTORE should be close by, and guaranteed to be called.

void  STORE_LC_NUMERIC_FORCE_TO_UNDERLYING()

#STORE_LC_NUMERIC_SET_TO_NEEDED

This is used to help wrap XS or C code that is LC_NUMERIC locale-aware. This locale category is generally kept set to a locale where the decimal radix character is a dot, and the separator between groups of digits is empty. This is because most XS code that reads floating point numbers is expecting them to have this syntax.

This macro makes sure the current LC_NUMERIC state is set properly, to be aware of locale if the call to the XS or C code from the Perl program is from within the scope of a use locale; or to ignore locale if the call is instead from outside such scope.

This macro is the start of wrapping the C or XS code; the wrap ending is done by calling the "RESTORE_LC_NUMERIC" macro after the operation. Otherwise the state can be changed that will adversely affect other XS code.

A call to "DECLARATION_FOR_LC_NUMERIC_MANIPULATION" must have been made to declare at compile time a private variable used by this macro. This macro should be called as a single statement, not an expression, but with an empty argument list, like this:

{
   DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
    ...
   STORE_LC_NUMERIC_SET_TO_NEEDED();
    ...
   RESTORE_LC_NUMERIC();
    ...
}

On threaded perls not operating with thread-safe functionality, this macro uses a mutex to force a critical section. Therefore the matching RESTORE should be close by, and guaranteed to be called; see "WITH_LC_NUMERIC_SET_TO_NEEDED" for a more contained way to ensure that.

void  STORE_LC_NUMERIC_SET_TO_NEEDED()

#STORE_LC_NUMERIC_SET_TO_NEEDED_IN

Same as "STORE_LC_NUMERIC_SET_TO_NEEDED" with in_lc_numeric provided as the precalculated value of IN_LC(LC_NUMERIC). It is the caller's responsibility to ensure that the status of PL_compiling and PL_hints cannot have changed since the precalculation.

void  STORE_LC_NUMERIC_SET_TO_NEEDED_IN(bool in_lc_numeric)

#sv_langinfo

#Perl_langinfo

#Perl_langinfo8

These perform the equivalent functionality as the system nl_langinfo(3), taking the same item parameter values, but are preferred over calling that directly because they are portable to platforms lacking that function, are thread-safe, and can automatically handle UTF-8 strings.

The simplest to use is sv_langinfo. It returns an SV containing the correct PV and UTF8ness, requiring no extra muss or fuss from you. New code should use this form.

Perl_langinfo and Perl_langinfo8 are retained for backwards compatibility. Perl_langinfo is an (almost) drop-in replacement for the system nl_langinfo(3), but exists on systems that lack a native nl_langinfo.

Perl_langinfo8 is identical to Perl_langinfo except for an additional parameter, a pointer to a variable declared as "utf8ness_t", into which it returns to you how you should treat the returned string with regards to it being encoded in UTF-8 or not.

Perl_langinfo and Perl_langinfo8 share private per-thread memory that will be changed the next time either one of them is called with any input, but not before.

Concerning the differences between these functions and plain nl_langinfo():

#a.

Perl_langinfo8 has an extra parameter, described above. Besides this, the other reason they aren't quite a drop-in replacement is actually an advantage. The constness of the return allows the compiler to catch attempts to write into the returned buffer, which is illegal and could cause run-time crashes.

#b.

They deliver the correct results for the RADIXCHAR and THOUSEP items, without you having to write extra code. The reason for the extra code would be because these are from the LC_NUMERIC locale category, which is normally kept set by Perl so that the radix is a dot, and the separator is the empty string, no matter what the underlying locale is supposed to be, and so to get the expected results, you have to temporarily toggle into the underlying locale, and later toggle back. (You could use plain nl_langinfo and "STORE_LC_NUMERIC_FORCE_TO_UNDERLYING" for this but then you wouldn't get the other advantages of Perl_langinfo(); not keeping LC_NUMERIC in the C (or equivalent) locale would break a lot of CPAN, which is expecting the radix (decimal point) character to be a dot.)

#c.

The system function they replace can have its static return buffer trashed, not only by a subsequent call to that function, but by a freelocale, setlocale, or other locale change. sv_langinfo sidesteps this problem entirely; the returned buffer of the other two is not changed until the next call to one or the other, so the buffer is never in a trashed state.

#d.

The return buffer of Perl_langinfo and Perl_langinfo8 is per-thread so it also is never overwritten by a call to these functions from another thread; unlike the function they replace.

#e.

But most importantly, they work on systems that don't have nl_langinfo, such as Windows, hence making your code more portable. Of the fifty-some possible items specified by the POSIX 2008 standard, https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/langinfo.h.html, only one is completely unimplemented, though on non-Windows platforms, another significant one is not fully implemented). They use various techniques to recover the other items, including calling localeconv(3), and strftime(3), both of which are specified in C89, so should be always be available. Later strftime() versions have additional capabilities. If an item is not available on your system, this returns either the value associated with the C locale, or simply "", whichever is more appropriate.

It is important to note that, when called with an item that is recovered by using localeconv, the buffer from any previous explicit call to localeconv(3) will be overwritten. But you shouldn't be using localeconv anyway because it is is very much not thread-safe, and suffers from the same problems outlined in item 'b.' above for the fields it returns that are controlled by the LC_NUMERIC locale category. Instead, avoid all of those problems by calling "Perl_localeconv", which is thread-safe; or by using the methods given in perlcall to call POSIX::localeconv(), which is also thread-safe.

The details for those items which may deviate from what this emulation returns and what a native nl_langinfo() would return are specified in I18N::Langinfo.

SV *               sv_langinfo   (      const nl_item item)
SV *          Perl_sv_langinfo   (pTHX_ const nl_item item)
const char *       Perl_langinfo (      const nl_item item)
const char *       Perl_langinfo8(      const nl_item item,
                                        utf8ness_t *utf8ness)

#switch_to_global_locale

This function copies the locale state of the calling thread into the program's global locale, and converts the thread to use that global locale.

It is intended so that Perl can safely be used with C libraries that access the global locale and which can't be converted to not access it. Effectively, this means libraries that call setlocale(3) on non-Windows systems. (For portability, it is a good idea to use it on Windows as well.)

A downside of using it is that it disables the services that Perl provides to hide locale gotchas from your code. The service you most likely will miss regards the radix character (decimal point) in floating point numbers. Code executed after this function is called can no longer just assume that this character is correct for the current circumstances.

To return to Perl control, and restart the gotcha prevention services, call "sync_locale". Behavior is undefined for any pure Perl code that executes while the switch is in effect.

The global locale and the per-thread locales are independent. As long as just one thread converts to the global locale, everything works smoothly. But if more than one does, they can easily interfere with each other, and races are likely. On Windows systems prior to Visual Studio 15 (at which point Microsoft fixed a bug), races can occur (even if only one thread has been converted to the global locale), but only if you use the following operations:

#POSIX::localeconv

#I18N::Langinfo, items CRNCYSTR and THOUSEP

#"sv_langinfo" in perlapi, items CRNCYSTR and THOUSEP

The first item is not fixable (except by upgrading to a later Visual Studio release), but it would be possible to work around the latter two items by having Perl change its algorithm for calculating these to use Windows API functions (likely GetNumberFormat and GetCurrencyFormat); patches welcome.

XS code should never call plain setlocale, but should instead be converted to either call Perl_setlocale (which is a drop-in for the system setlocale) or use the methods given in perlcall to call POSIX::setlocale. Either one will transparently properly handle all cases of single- vs multi-thread, POSIX 2008-supported or not.

void       switch_to_global_locale()
void  Perl_switch_to_global_locale(pTHX)

#sync_locale

This function copies the state of the program global locale into the calling thread, and converts that thread to using per-thread locales, if it wasn't already, and the platform supports them. The LC_NUMERIC locale is toggled into the standard state (using the C locale's conventions), if not within the lexical scope of use locale.

Perl will now consider itself to have control of the locale.

Since unthreaded perls have only a global locale, this function is a no-op without threads.

This function is intended for use with C libraries that do locale manipulation. It allows Perl to accommodate the use of them. Call this function before transferring back to Perl space so that it knows what state the C code has left things in.

XS code should not manipulate the locale on its own. Instead, Perl_setlocale can be used at any time to query or change the locale (though changing the locale is antisocial and dangerous on multi-threaded systems that don't have multi-thread safe locale operations. (See "Multi-threaded operation" in perllocale).

Using the libc setlocale(3) function should be avoided. Nevertheless, certain non-Perl libraries called from XS, do call it, and their behavior may not be able to be changed. This function, along with "switch_to_global_locale", can be used to get seamless behavior in these circumstances, as long as only one thread is involved.

If the library has an option to turn off its locale manipulation, doing that is preferable to using this mechanism. Gtk is such a library.

The return value is a boolean: TRUE if the global locale at the time of call was in effect for the caller; and FALSE if a per-thread locale was in effect.

bool       sync_locale()
bool  Perl_sync_locale(pTHX)

#WITH_LC_NUMERIC_SET_TO_NEEDED

This macro invokes the supplied statement or block within the context of a "STORE_LC_NUMERIC_SET_TO_NEEDED" .. "RESTORE_LC_NUMERIC" pair if required, so eg:

WITH_LC_NUMERIC_SET_TO_NEEDED(
  SNPRINTF_G(fv, ebuf, sizeof(ebuf), precis)
);

is equivalent to:

{
#ifdef USE_LOCALE_NUMERIC
  DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
  STORE_LC_NUMERIC_SET_TO_NEEDED();
#endif
  SNPRINTF_G(fv, ebuf, sizeof(ebuf), precis);
#ifdef USE_LOCALE_NUMERIC
  RESTORE_LC_NUMERIC();
#endif
}

void  WITH_LC_NUMERIC_SET_TO_NEEDED(block)

#WITH_LC_NUMERIC_SET_TO_NEEDED_IN

Same as "WITH_LC_NUMERIC_SET_TO_NEEDED" with in_lc_numeric provided as the precalculated value of IN_LC(LC_NUMERIC). It is the caller's responsibility to ensure that the status of PL_compiling and PL_hints cannot have changed since the precalculation.

void  WITH_LC_NUMERIC_SET_TO_NEEDED_IN(bool in_lc_numeric, block)

#Magic

"Magic" is special data attached to SV structures in order to give them "magical" properties. When any Perl code tries to read from, or assign to, an SV marked as magical, it calls the 'get' or 'set' function associated with that SV's magic. A get is called prior to reading an SV, in order to give it a chance to update its internal value (get on $. writes the line number of the last read filehandle into the SV's IV slot), while set is called after an SV has been written to, in order to allow it to make use of its changed value (set on $/ copies the SV's new value to the PL_rs global variable).

Magic is implemented as a linked list of MAGIC structures attached to the SV. Each MAGIC struct holds the type of the magic, a pointer to an array of functions that implement the get(), set(), length() etc functions, plus space for some flags and pointers. For example, a tied variable has a MAGIC structure that contains a pointer to the object associated with the tie.

#mg_clear

Clear something magical that the SV represents. See "sv_magic".

int       mg_clear(      SV *sv)
int  Perl_mg_clear(pTHX_ SV *sv)

#mg_copy

Copies the magic from one SV to another. See "sv_magic".

int       mg_copy(      SV *sv, SV *nsv, const char *key,
                        I32 klen)
int  Perl_mg_copy(pTHX_ SV *sv, SV *nsv, const char *key,
                        I32 klen)

#mg_find

Finds the magic pointer for type matching the SV. See "sv_magic".

MAGIC *       mg_find(const SV *sv, int type)
MAGIC *  Perl_mg_find(const SV *sv, int type)

#mg_findext

Finds the magic pointer of type with the given vtbl for the SV. See "sv_magicext".

MAGIC *       mg_findext(const SV *sv, int type,
                         const MGVTBL *vtbl)
MAGIC *  Perl_mg_findext(const SV *sv, int type,
                         const MGVTBL *vtbl)

#mg_free

Free any magic storage used by the SV. See "sv_magic".

int       mg_free(      SV *sv)
int  Perl_mg_free(pTHX_ SV *sv)

#mg_free_type

Remove any magic of type how from the SV sv. See "sv_magic".

void       mg_free_type(      SV *sv, int how)
void  Perl_mg_free_type(pTHX_ SV *sv, int how)

#mg_freeext

Remove any magic of type how using virtual table vtbl from the SV sv. See "sv_magic".

mg_freeext(sv, how, NULL) is equivalent to mg_free_type(sv, how).

void       mg_freeext(      SV *sv, int how, const MGVTBL *vtbl)
void  Perl_mg_freeext(pTHX_ SV *sv, int how, const MGVTBL *vtbl)

#mg_get

Do magic before a value is retrieved from the SV. The type of SV must be >= SVt_PVMG. See "sv_magic".

int       mg_get(      SV *sv)
int  Perl_mg_get(pTHX_ SV *sv)

#mg_magical

Turns on the magical status of an SV. See "sv_magic".

void       mg_magical(SV *sv)
void  Perl_mg_magical(SV *sv)

#mg_set

Do magic after a value is assigned to the SV. See "sv_magic".

int       mg_set(      SV *sv)
int  Perl_mg_set(pTHX_ SV *sv)

#MGf_COPY

#MGf_DUP

#MGf_LOCAL

#MGVTBL

#PERL_MAGIC_arylen

#PERL_MAGIC_arylen_p

#PERL_MAGIC_backref

#PERL_MAGIC_bm

#PERL_MAGIC_checkcall

#PERL_MAGIC_collxfrm

#PERL_MAGIC_dbfile

#PERL_MAGIC_dbline

#PERL_MAGIC_debugvar

#PERL_MAGIC_defelem

#PERL_MAGIC_destruct

#PERL_MAGIC_env

#PERL_MAGIC_envelem

#PERL_MAGIC_ext

#PERL_MAGIC_extvalue

#PERL_MAGIC_fm

#PERL_MAGIC_hints

#PERL_MAGIC_hintselem

#PERL_MAGIC_hook

#PERL_MAGIC_hookelem

#PERL_MAGIC_isa

#PERL_MAGIC_isaelem

#PERL_MAGIC_lvref

#PERL_MAGIC_nkeys

#PERL_MAGIC_nonelem

#PERL_MAGIC_overload_table

#PERL_MAGIC_pos

#PERL_MAGIC_qr

#PERL_MAGIC_regdata

#PERL_MAGIC_regdatum

#PERL_MAGIC_regex_global

#PERL_MAGIC_rhash

#PERL_MAGIC_shared

#PERL_MAGIC_shared_scalar

#PERL_MAGIC_sig

#PERL_MAGIC_sigelem

#PERL_MAGIC_substr

#PERL_MAGIC_sv

#PERL_MAGIC_symtab

#PERL_MAGIC_taint

#PERL_MAGIC_tied

#PERL_MAGIC_tiedelem

#PERL_MAGIC_tiedscalar

#PERL_MAGIC_utf8

#PERL_MAGIC_uvar

#PERL_MAGIC_uvar_elem

#PERL_MAGIC_vec

#PERL_MAGIC_vstring

Described in perlguts.

#SvTIED_obj

Described in perlinterp.

SvTIED_obj(SV *sv, MAGIC *mg)

#Memory Management

#dump_mstats

When enabled by compiling with -DDEBUGGING_MSTATS, print out statistics about malloc as two lines of numbers, one showing the length of the free list for each size category, the second showing the number of mallocs - frees for each size category.

s, if not NULL, is used as a phrase to include in the output, such as "after compilation".

void       dump_mstats(      const char *s)
void  Perl_dump_mstats(pTHX_ const char *s)

#HAS_MALLOC_GOOD_SIZE

This symbol, if defined, indicates that the malloc_good_size routine is available for use.

#HAS_MALLOC_SIZE

This symbol, if defined, indicates that the malloc_size routine is available for use.

#HASATTRIBUTE_MALLOC

Can we handle GCC attribute for malloc-style functions.

#I_MALLOCMALLOC

This symbol, if defined, indicates to the C program that it should include malloc/malloc.h.

#ifdef I_MALLOCMALLOC
    #include <mallocmalloc.h>
#endif

#MYMALLOC

This symbol, if defined, indicates that we're using our own malloc.

#Newx

#safemalloc

The XSUB-writer's interface to the C malloc function.

Memory obtained by this should ONLY be freed with "Safefree".

In 5.9.3, Newx() and friends replace the older New() API, and drops the first parameter, x, a debug aid which allowed callers to identify themselves. This aid has been superseded by a new build option, PERL_MEM_LOG (see "PERL_MEM_LOG" in perlhacktips). The older API is still there for use in XS modules supporting older perls.

void   Newx      (void* ptr, int nitems, type)
void*  safemalloc(size_t size)

#Newxc

The XSUB-writer's interface to the C malloc function, with cast. See also "Newx".

Memory obtained by this should ONLY be freed with "Safefree".

void  Newxc(void* ptr, int nitems, type, cast)

#Newxz

#safecalloc

The XSUB-writer's interface to the C calloc function. The allocated memory is zeroed with memzero. See also "Newx".

Memory obtained by this should ONLY be freed with "Safefree".

void   Newxz     (void* ptr, int nitems, type)
void*  safecalloc(size_t nitems, size_t item_size)

#PERL_MALLOC_WRAP

This symbol, if defined, indicates that we'd like malloc wrap checks.

#Renew

#saferealloc

The XSUB-writer's interface to the C realloc function.

Memory obtained by this should ONLY be freed with "Safefree".

void   Renew      (void* ptr, int nitems, type)
void*  saferealloc(void *ptr, size_t size)

#Renewc

The XSUB-writer's interface to the C realloc function, with cast.

Memory obtained by this should ONLY be freed with "Safefree".

void  Renewc(void* ptr, int nitems, type, cast)

#safecalloc*

Described under "Newxz"

#Safefree

The XSUB-writer's interface to the C free function.

This should ONLY be used on memory obtained using "Newx" and friends.

void  Safefree(void* ptr)

#safemalloc*

Described under "Newx"

#saferealloc*

Described under "Renew"

#safesyscalloc

Safe version of system's calloc()

Malloc_t       safesyscalloc(MEM_SIZE elements, MEM_SIZE size)
Malloc_t  Perl_safesyscalloc(MEM_SIZE elements, MEM_SIZE size)

#safesysfree

Safe version of system's free()

Free_t       safesysfree(Malloc_t where)
Free_t  Perl_safesysfree(Malloc_t where)

#safesysmalloc

Paranoid version of system's malloc()

Malloc_t       safesysmalloc(MEM_SIZE nbytes)
Malloc_t  Perl_safesysmalloc(MEM_SIZE nbytes)

#safesysrealloc

Paranoid version of system's realloc()

Malloc_t       safesysrealloc(Malloc_t where, MEM_SIZE nbytes)
Malloc_t  Perl_safesysrealloc(Malloc_t where, MEM_SIZE nbytes)

#MRO

These functions are related to the method resolution order of perl classes Also see perlmroapi.

#HvMROMETA

Described in perlmroapi.

struct mro_meta *  HvMROMETA(HV *hv)

#mro_get_from_name

Returns the previously registered mro with the given name, or NULL if not registered. See "mro_register".

const struct mro_alg *  Perl_mro_get_from_name(pTHX_ SV *name)

#mro_get_linear_isa

Returns the mro linearisation for the given stash. By default, this will be whatever mro_get_linear_isa_dfs returns unless some other MRO is in effect for the stash. The return value is a read-only AV* whose values are string SVs giving class names.

You are responsible for SvREFCNT_inc() on the return value if you plan to store it anywhere semi-permanently (otherwise it might be deleted out from under you the next time the cache is invalidated).

AV *       mro_get_linear_isa(      HV *stash)
AV *  Perl_mro_get_linear_isa(pTHX_ HV *stash)

#MRO_GET_PRIVATE_DATA

Described in perlmroapi.

SV*  MRO_GET_PRIVATE_DATA(struct mro_meta *const smeta,
                          const struct mro_alg *const which)

#mro_method_changed_in

Invalidates method caching on any child classes of the given stash, so that they might notice the changes in this one.

Ideally, all instances of PL_sub_generation++ in perl source outside of mro.c should be replaced by calls to this.

Perl automatically handles most of the common ways a method might be redefined. However, there are a few ways you could change a method in a stash without the cache code noticing, in which case you need to call this method afterwards:

1) Directly manipulating the stash HV entries from XS code.

2) Assigning a reference to a readonly scalar constant into a stash entry in order to create a constant subroutine (like constant.pm does).

This same method is available from pure perl via, mro::method_changed_in(classname).

void       mro_method_changed_in(      HV *stash)
void  Perl_mro_method_changed_in(pTHX_ HV *stash)

#mro_register

Registers a custom mro plugin. See perlmroapi for details on this and other mro functions.

void  Perl_mro_register(pTHX_ const struct mro_alg *mro)

#mro_set_mro

Set meta to the value contained in the registered mro plugin whose name is name.

Croaks if name hasn't been registered

void  Perl_mro_set_mro(pTHX_ struct mro_meta * const meta,
                             SV * const name)

#mro_set_private_data

Described in perlmroapi.

SV *  Perl_mro_set_private_data(pTHX_
                              struct mro_meta * const smeta,
                              const struct mro_alg * const which,
                              SV * const data)

#Multicall Functions

#dMULTICALL

Declare local variables for a multicall. See "LIGHTWEIGHT CALLBACKS" in perlcall.

dMULTICALL;

#MULTICALL

Make a lightweight callback. See "LIGHTWEIGHT CALLBACKS" in perlcall.

MULTICALL;

#POP_MULTICALL

Closing bracket for a lightweight callback. See "LIGHTWEIGHT CALLBACKS" in perlcall.

POP_MULTICALL;

#PUSH_MULTICALL

Opening bracket for a lightweight callback. See "LIGHTWEIGHT CALLBACKS" in perlcall.

PUSH_MULTICALL(CV* the_cv);

#Numeric Functions

#Atof*

Described under "my_atof"

#grok_atoUV

parse a string, looking for a decimal unsigned integer.

On entry, pv points to the beginning of the string; valptr points to a UV that will receive the converted value, if found; endptr is either NULL or points to a variable that points to one byte beyond the point in pv that this routine should examine. If endptr is NULL, pv is assumed to be NUL-terminated.

Returns FALSE if pv doesn't represent a valid unsigned integer value (with no leading zeros). Otherwise it returns TRUE, and sets *valptr to that value.

If you constrain the portion of pv that is looked at by this function (by passing a non-NULL endptr), and if the initial bytes of that portion form a valid value, it will return TRUE, setting *endptr to the byte following the final digit of the value. But if there is no constraint at what's looked at, all of pv must be valid in order for TRUE to be returned. *endptr is unchanged from its value on input if FALSE is returned;

The only characters this accepts are the decimal digits '0'..'9'.

As opposed to atoi(3) or strtol(3), grok_atoUV does NOT allow optional leading whitespace, nor negative inputs. If such features are required, the calling code needs to explicitly implement those.

Note that this function returns FALSE for inputs that would overflow a UV, or have leading zeros. Thus a single 0 is accepted, but not 00 nor 01, 002, etc.

Background: atoi has severe problems with illegal inputs, it cannot be used for incremental parsing, and therefore should be avoided atoi and strtol are also affected by locale settings, which can also be seen as a bug (global state controlled by user environment).

bool       grok_atoUV(const char *pv, UV *valptr,
                      const char **endptr)
bool  Perl_grok_atoUV(const char *pv, UV *valptr,
                      const char **endptr)

#grok_bin

converts a string representing a binary number to numeric form.

On entry start and *len_p give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or at just before the first invalid character. Unless PERL_SCAN_SILENT_ILLDIGIT is set in *flags, encountering an invalid character (except NUL) will also trigger a warning. On return *len_p is set to the length of the scanned string, and *flags gives output flags.

If the value is <= UV_MAX it is returned as a UV, the output flags are clear, and nothing is written to *result. If the value is > UV_MAX, grok_bin returns UV_MAX, sets PERL_SCAN_GREATER_THAN_UV_MAX in the output flags, and writes an approximation of the correct value into *result (which is an NV; or the approximation is discarded if result is NULL).

The binary number may optionally be prefixed with "0b" or "b" unless PERL_SCAN_DISALLOW_PREFIX is set in *flags on entry.

If PERL_SCAN_ALLOW_UNDERSCORES is set in *flags then any or all pairs of digits may be separated from each other by a single underscore; also a single leading underscore is accepted.

UV       grok_bin(      const char *start, STRLEN *len_p,
                        I32 *flags, NV *result)
UV  Perl_grok_bin(pTHX_ const char *start, STRLEN *len_p,
                        I32 *flags, NV *result)

#grok_hex

converts a string representing a hex number to numeric form.

On entry start and *len_p give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or at just before the first invalid character. Unless PERL_SCAN_SILENT_ILLDIGIT is set in *flags, encountering an invalid character (except NUL) will also trigger a warning. On return *len_p is set to the length of the scanned string, and *flags gives output flags.

If the value is <= UV_MAX it is returned as a UV, the output flags are clear, and nothing is written to *result. If the value is > UV_MAX, grok_hex returns UV_MAX, sets PERL_SCAN_GREATER_THAN_UV_MAX in the output flags, and writes an approximation of the correct value into *result (which is an NV; or the approximation is discarded if result is NULL).

The hex number may optionally be prefixed with "0x" or "x" unless PERL_SCAN_DISALLOW_PREFIX is set in *flags on entry.

If PERL_SCAN_ALLOW_UNDERSCORES is set in *flags then any or all pairs of digits may be separated from each other by a single underscore; also a single leading underscore is accepted.

UV       grok_hex(      const char *start, STRLEN *len_p,
                        I32 *flags, NV *result)
UV  Perl_grok_hex(pTHX_ const char *start, STRLEN *len_p,
                        I32 *flags, NV *result)

#grok_infnan

Helper for grok_number(), accepts various ways of spelling "infinity" or "not a number", and returns one of the following flag combinations:

IS_NUMBER_INFINITY
IS_NUMBER_NAN
IS_NUMBER_INFINITY | IS_NUMBER_NEG
IS_NUMBER_NAN | IS_NUMBER_NEG
0

possibly |-ed with IS_NUMBER_TRAILING.

If an infinity or a not-a-number is recognized, *sp will point to one byte past the end of the recognized string. If the recognition fails, zero is returned, and *sp will not move.

int       grok_infnan(      const char **sp, const char *send)
int  Perl_grok_infnan(pTHX_ const char **sp, const char *send)

#grok_number

#grok_number_flags

Look for a number in the len bytes starting at pv. If one isn't found, return 0; otherwise return its type (and optionally its value). In grok_number all len bytes must be either leading "isSPACE" characters or part of the number. The same is true in grok_number_flags unless flags contains the PERL_SCAN_TRAILING bit, which allows for trailing non-numeric text. (This is the only difference between the two functions.)

The returned type is the ORing of various bits (#defined in perl.h) as described below:

If the number is negative, the returned type will include the IS_NUMBER_NEG bit.

If the absolute value of the integral portion of the found number fits in a UV, the returned type will include the IS_NUMBER_IN_UV bit. If it won't fit, instead the IS_NUMBER_GREATER_THAN_UV_MAX bit will be included.

If the found number is not an integer, the returned type will include the IS_NUMBER_NOT_INT bit. This happens either if the number is expressed in exponential e notation, or if it includes a decimal point (radix) character. If exponential notation is used, then neither IS_NUMBER_IN_UV nor IS_NUMBER_GREATER_THAN_UV_MAX bits are set. Otherwise, the integer part of the number is used to determine the IS_NUMBER_IN_UV and IS_NUMBER_GREATER_THAN_UV_MAX bits.

If the found number is a string indicating it is infinity, the IS_NUMBER_INFINITY and IS_NUMBER_NOT_INT bits are included in the returned type.

If the found number is a string indicating it is not a number, the IS_NUMBER_NAN and IS_NUMBER_NOT_INT bits are included in the returned type.

You can get the number's absolute integral value returned to you by calling these functions with a non-NULL valuep argument. If the returned type includes the IS_NUMBER_IN_UV bit, *valuep will be set to the correct value. Otherwise, it could well have been zapped with garbage.

In grok_number_flags when flags contains the PERL_SCAN_TRAILING bit, and trailing non-numeric text was found, the returned type will include the IS_NUMBER_TRAILING bit.

int       grok_number      (      const char *pv, STRLEN len,
                                  UV *valuep)
int  Perl_grok_number      (pTHX_ const char *pv, STRLEN len,
                                  UV *valuep)
int       grok_number_flags(      const char *pv, STRLEN len,
                                  UV *valuep, U32 flags)
int  Perl_grok_number_flags(pTHX_ const char *pv, STRLEN len,
                                  UV *valuep, U32 flags)

#grok_numeric_radix

#GROK_NUMERIC_RADIX

These are identical.

Scan and skip for a numeric decimal separator (radix).

bool       grok_numeric_radix(      const char **sp,
                                    const char *send)
bool  Perl_grok_numeric_radix(pTHX_ const char **sp,
                                    const char *send)
bool       GROK_NUMERIC_RADIX(      const char **sp,
                                    const char *send)

#grok_oct

converts a string representing an octal number to numeric form.

On entry start and *len_p give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or at just before the first invalid character. Unless PERL_SCAN_SILENT_ILLDIGIT is set in *flags, encountering an invalid character (except NUL) will also trigger a warning. On return *len_p is set to the length of the scanned string, and *flags gives output flags.

If the value is <= UV_MAX it is returned as a UV, the output flags are clear, and nothing is written to *result. If the value is > UV_MAX, grok_oct returns UV_MAX, sets PERL_SCAN_GREATER_THAN_UV_MAX in the output flags, and writes an approximation of the correct value into *result (which is an NV; or the approximation is discarded if result is NULL).

If PERL_SCAN_ALLOW_UNDERSCORES is set in *flags then any or all pairs of digits may be separated from each other by a single underscore; also a single leading underscore is accepted.

The PERL_SCAN_DISALLOW_PREFIX flag is always treated as being set for this function.

UV       grok_oct(      const char *start, STRLEN *len_p,
                        I32 *flags, NV *result)
UV  Perl_grok_oct(pTHX_ const char *start, STRLEN *len_p,
                        I32 *flags, NV *result)

#isinfnan

Perl_isinfnan() is a utility function that returns true if the NV argument is either an infinity or a NaN, false otherwise. To test in more detail, use Perl_isinf() and Perl_isnan().

This is also the logical inverse of Perl_isfinite().

bool       isinfnan(NV nv)
bool  Perl_isinfnan(NV nv)

#my_atof

#Atof

These each are atof(3), but properly work with Perl locale handling, accepting a dot radix character always, but also the current locale's radix character if and only if called from within the lexical scope of a Perl use locale statement.

N.B. s must be NUL terminated.

NV       my_atof(      const char *s)
NV  Perl_my_atof(pTHX_ const char *s)
NV       Atof   (      const char * const s)

#my_strtod

#Strtod

These are identical.

They act like the libc strtod(3) function, with three exceptions:

1. Their return value is an NV. Plain strod returns a double precision value.

2. Plain strtod always is expecting the radix character (or string) to be the one specified by the underlying locale the program is executing in. This is almost universally a dot (U+002E) or a comma (U+002C).

   In contrast, these expect the radix to be a dot, except when called from within the scope of use locale, in which case they act like plain strtod, expecting the radix to be that specified by the current locale.

3. These are are available even on platforms that lack plain strtod().

NV       my_strtod(const char * const s, char **e)
NV  Perl_my_strtod(const char * const s, char **e)
NV       Strtod   (const char * const s, char **e)

#PERL_ABS

Typeless abs or fabs, etc. (The usage below indicates it is for integers, but it works for any type.) Use instead of these, since the C library ones force their argument to be what it is expecting, potentially leading to disaster. But also beware that this evaluates its argument twice, so no x++.

int  PERL_ABS(int x)

#Perl_acos

#Perl_asin

#Perl_atan

#Perl_atan2

#Perl_ceil

#Perl_cos

#Perl_cosh

#Perl_exp

#Perl_floor

#Perl_fmod

#Perl_frexp

#Perl_isfinite

#Perl_isinf

#Perl_isnan

#Perl_ldexp

#Perl_log

#Perl_log10

#Perl_modf

#Perl_pow

#Perl_sin

#Perl_sinh

#Perl_sqrt

#Perl_tan

#Perl_tanh

These perform the corresponding mathematical operation on the operand(s), using the libc function designed for the task that has just enough precision for an NV on this platform. If no such function with sufficient precision exists, the highest precision one available is used.

NV  Perl_acos    (NV x)
NV  Perl_asin    (NV x)
NV  Perl_atan    (NV x)
NV  Perl_atan2   (NV x, NV y)
NV  Perl_ceil    (NV x)
NV  Perl_cos     (NV x)
NV  Perl_cosh    (NV x)
NV  Perl_exp     (NV x)
NV  Perl_floor   (NV x)
NV  Perl_fmod    (NV x, NV y)
NV  Perl_frexp   (NV x, int *exp)
IV  Perl_isfinite(NV x)
IV  Perl_isinf   (NV x)
IV  Perl_isnan   (NV x)
NV  Perl_ldexp   (NV x, int exp)
NV  Perl_log     (NV x)
NV  Perl_log10   (NV x)
NV  Perl_modf    (NV x, NV *iptr)
NV  Perl_pow     (NV x, NV y)
NV  Perl_sin     (NV x)
NV  Perl_sinh    (NV x)
NV  Perl_sqrt    (NV x)
NV  Perl_tan     (NV x)
NV  Perl_tanh    (NV x)

#Perl_signbit

NOTE: Perl_signbit is experimental and may change or be removed without notice.

Return a non-zero integer if the sign bit on an NV is set, and 0 if it is not.

If Configure detects this system has a signbit() that will work with our NVs, then we just use it via the #define in perl.h. Otherwise, fall back on this implementation. The main use of this function is catching -0.0.

Configure notes: This function is called 'Perl_signbit' instead of a plain 'signbit' because it is easy to imagine a system having a signbit() function or macro that doesn't happen to work with our particular choice of NVs. We shouldn't just re-#define signbit as Perl_signbit and expect the standard system headers to be happy. Also, this is a no-context function (no pTHX_) because Perl_signbit() is usually re-#defined in perl.h as a simple macro call to the system's signbit(). Users should just always call Perl_signbit().

int  Perl_signbit(NV f)

#Perl_sin*

#Perl_sinh*

#Perl_sqrt*

#Perl_tan*

#Perl_tanh*

Described under "Perl_acos"

#PL_hexdigit

This array, indexed by an integer, converts that value into the character that represents it. For example, if the input is 8, the return will be a string whose first character is '8'. What is actually returned is a pointer into a string. All you are interested in is the first character of that string. To get uppercase letters (for the values 10..15), add 16 to the index. Hence, PL_hexdigit[11] is 'b', and PL_hexdigit[11+16] is 'B'. Adding 16 to an index whose representation is '0'..'9' yields the same as not adding 16. Indices outside the range 0..31 result in (bad) undefined behavior.

#READ_XDIGIT

Returns the value of an ASCII-range hex digit and advances the string pointer. Behaviour is only well defined when isXDIGIT(*str) is true.

U8  READ_XDIGIT(char str*)

#scan_bin

For backwards compatibility. Use grok_bin instead.

NV       scan_bin(      const char *start, STRLEN len,
                        STRLEN *retlen)
NV  Perl_scan_bin(pTHX_ const char *start, STRLEN len,
                        STRLEN *retlen)

#scan_hex

For backwards compatibility. Use grok_hex instead.

NV       scan_hex(      const char *start, STRLEN len,
                        STRLEN *retlen)
NV  Perl_scan_hex(pTHX_ const char *start, STRLEN len,
                        STRLEN *retlen)

#scan_oct

For backwards compatibility. Use grok_oct instead.

NV       scan_oct(      const char *start, STRLEN len,
                        STRLEN *retlen)
NV  Perl_scan_oct(pTHX_ const char *start, STRLEN len,
                        STRLEN *retlen)

#Strtod*

Described under "my_strtod"

#Strtol

Platform and configuration independent strtol. This expands to the appropriate strotol-like function based on the platform and Configure options>. For example it could expand to strtoll or strtoq instead of strtol.

NV  Strtol(const char * const s, char ** e, int base)

#Strtoul

Platform and configuration independent strtoul. This expands to the appropriate strotoul-like function based on the platform and Configure options>. For example it could expand to strtoull or strtouq instead of strtoul.

NV  Strtoul(const char * const s, char ** e, int base)

#Optrees

#alloccopstash

NOTE: alloccopstash is experimental and may change or be removed without notice.

Available only under threaded builds, this function allocates an entry in PL_stashpad for the stash passed to it.

PADOFFSET       alloccopstash(      HV *hv)
PADOFFSET  Perl_alloccopstash(pTHX_ HV *hv)

#BINOP

Described in perlguts.

#block_end

Handles compile-time scope exit. floor is the savestack index returned by block_start, and seq is the body of the block. Returns the block, possibly modified.

OP *       block_end(      I32 floor, OP *seq)
OP *  Perl_block_end(pTHX_ I32 floor, OP *seq)

#block_start

Handles compile-time scope entry. Arranges for hints to be restored on block exit and also handles pad sequence numbers to make lexical variables scope right. Returns a savestack index for use with block_end.

int       block_start(      int full)
int  Perl_block_start(pTHX_ int full)

#ck_entersub_args_list

Performs the default fixup of the arguments part of an entersub op tree. This consists of applying list context to each of the argument ops. This is the standard treatment used on a call marked with &, or a method call, or a call through a subroutine reference, or any other call where the callee can't be identified at compile time, or a call where the callee has no prototype.

OP *       ck_entersub_args_list(      OP *entersubop)
OP *  Perl_ck_entersub_args_list(pTHX_ OP *entersubop)

#ck_entersub_args_proto

Performs the fixup of the arguments part of an entersub op tree based on a subroutine prototype. This makes various modifications to the argument ops, from applying context up to inserting refgen ops, and checking the number and syntactic types of arguments, as directed by the prototype. This is the standard treatment used on a subroutine call, not marked with &, where the callee can be identified at compile time and has a prototype.

protosv supplies the subroutine prototype to be applied to the call. It may be a normal defined scalar, of which the string value will be used. Alternatively, for convenience, it may be a subroutine object (a CV* that has been cast to SV*) which has a prototype. The prototype supplied, in whichever form, does not need to match the actual callee referenced by the op tree.

If the argument ops disagree with the prototype, for example by having an unacceptable number of arguments, a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. In the error message, the callee is referred to by the name defined by the namegv parameter.

OP *       ck_entersub_args_proto(      OP *entersubop,
                                        GV *namegv, SV *protosv)
OP *  Perl_ck_entersub_args_proto(pTHX_ OP *entersubop,
                                        GV *namegv, SV *protosv)

#ck_entersub_args_proto_or_list

Performs the fixup of the arguments part of an entersub op tree either based on a subroutine prototype or using default list-context processing. This is the standard treatment used on a subroutine call, not marked with &, where the callee can be identified at compile time.

protosv supplies the subroutine prototype to be applied to the call, or indicates that there is no prototype. It may be a normal scalar, in which case if it is defined then the string value will be used as a prototype, and if it is undefined then there is no prototype. Alternatively, for convenience, it may be a subroutine object (a CV* that has been cast to SV*), of which the prototype will be used if it has one. The prototype (or lack thereof) supplied, in whichever form, does not need to match the actual callee referenced by the op tree.

If the argument ops disagree with the prototype, for example by having an unacceptable number of arguments, a valid op tree is returned anyway. The error is reflected in the parser state, normally resulting in a single exception at the top level of parsing which covers all the compilation errors that occurred. In the error message, the callee is referred to by the name defined by the namegv parameter.

OP *       ck_entersub_args_proto_or_list(      OP *entersubop,
                                                GV *namegv,
                                                SV *protosv)
OP *  Perl_ck_entersub_args_proto_or_list(pTHX_ OP *entersubop,
                                                GV *namegv,
                                                SV *protosv)

#cv_const_sv

If cv is a constant sub eligible for inlining, returns the constant value returned by the sub. Otherwise, returns NULL.

Constant subs can be created with newCONSTSUB or as described in "Constant Functions" in perlsub.

SV *       cv_const_sv(const CV * const cv)
SV *  Perl_cv_const_sv(const CV * const cv)

#cv_get_call_checker

The original form of "cv_get_call_checker_flags", which does not return checker flags. When using a checker function returned by this function, it is only safe to call it with a genuine GV as its namegv argument.

void       cv_get_call_checker(      CV *cv,
                                     Perl_call_checker *ckfun_p,
                                     SV **ckobj_p)
void  Perl_cv_get_call_checker(pTHX_ CV *cv,
                                     Perl_call_checker *ckfun_p,
                                     SV **ckobj_p)

#cv_get_call_checker_flags

Retrieves the function that will be used to fix up a call to cv. Specifically, the function is applied to an entersub op tree for a subroutine call, not marked with &, where the callee can be identified at compile time as cv.

The C-level function pointer is returned in *ckfun_p, an SV argument for it is returned in *ckobj_p, and control flags are returned in *ckflags_p. The function is intended to be called in this manner:

entersubop = (*ckfun_p)(aTHX_ entersubop, namegv, (*ckobj_p));

In this call, entersubop is a pointer to the entersub op, which may be replaced by the check function, and namegv supplies the name that should be used by the check function to refer to the callee of the entersub op if it needs to emit any diagnostics. It is permitted to apply the check function in non-standard situations, such as to a call to a different subroutine or to a method call.

namegv may not actually be a GV. If the CALL_CHECKER_REQUIRE_GV bit is clear in *ckflags_p, it is permitted to pass a CV or other SV instead, anything that can be used as the first argument to "cv_name". If the CALL_CHECKER_REQUIRE_GV bit is set in *ckflags_p then the check function requires namegv to be a genuine GV.

By default, the check function is Perl_ck_entersub_args_proto_or_list, the SV parameter is cv itself, and the CALL_CHECKER_REQUIRE_GV flag is clear. This implements standard prototype processing. It can be changed, for a particular subroutine, by "cv_set_call_checker_flags".

If the CALL_CHECKER_REQUIRE_GV bit is set in gflags then it indicates that the caller only knows about the genuine GV version of namegv, and accordingly the corresponding bit will always be set in *ckflags_p, regardless of the check function's recorded requirements. If the CALL_CHECKER_REQUIRE_GV bit is clear in gflags then it indicates the caller knows about the possibility of passing something other than a GV as namegv, and accordingly the corresponding bit may be either set or clear in *ckflags_p, indicating the check function's recorded requirements.

gflags is a bitset passed into cv_get_call_checker_flags, in which only the CALL_CHECKER_REQUIRE_GV bit currently has a defined meaning (for which see above). All other bits should be clear.

void       cv_get_call_checker_flags(CV *cv, U32 gflags,
                                      Perl_call_checker *ckfun_p,
                                      SV **ckobj_p,
                                      U32 *ckflags_p)
void  Perl_cv_get_call_checker_flags(pTHX_ CV *cv, U32 gflags,
                                      Perl_call_checker *ckfun_p,
                                      SV **ckobj_p,
                                      U32 *ckflags_p)

#cv_set_call_checker

The original form of "cv_set_call_checker_flags", which passes it the CALL_CHECKER_REQUIRE_GV flag for backward-compatibility. The effect of that flag setting is that the check function is guaranteed to get a genuine GV as its namegv argument.

void       cv_set_call_checker(      CV *cv,
                                     Perl_call_checker ckfun,
                                     SV *ckobj)
void  Perl_cv_set_call_checker(pTHX_ CV *cv,
                                     Perl_call_checker ckfun,
                                     SV *ckobj)

#cv_set_call_checker_flags

Sets the function that will be used to fix up a call to cv. Specifically, the function is applied to an entersub op tree for a subroutine call, not marked with &, where the callee can be identified at compile time as cv.

The C-level function pointer is supplied in ckfun, an SV argument for it is supplied in ckobj, and control flags are supplied in ckflags. The function should be defined like this:

STATIC OP * ckfun(pTHX_ OP *op, GV *namegv, SV *ckobj)

It is intended to be called in this manner:

entersubop = ckfun(aTHX_ entersubop, namegv, ckobj);

In this call, entersubop is a pointer to the entersub op, which may be replaced by the check function, and namegv supplies the name that should be used by the check function to refer to the callee of the entersub op if it needs to emit any diagnostics. It is permitted to apply the check function in non-standard situations, such as to a call to a different subroutine or to a method call.

namegv may not actually be a GV. For efficiency, perl may pass a CV or other SV instead. Whatever is passed can be used as the first argument to "cv_name". You can force perl to pass a GV by including CALL_CHECKER_REQUIRE_GV in the ckflags.

ckflags is a bitset, in which only the CALL_CHECKER_REQUIRE_GV bit currently has a defined meaning (for which see above). All other bits should be clear.

The current setting for a particular CV can be retrieved by "cv_get_call_checker_flags".

void       cv_set_call_checker_flags(    CV *cv,
                                         Perl_call_checker ckfun,
                                         SV *ckobj, U32 ckflags)
void  Perl_cv_set_call_checker_flags(pTHX_ CV *cv,
                                         Perl_call_checker ckfun,
                                         SV *ckobj, U32 ckflags)

#finalize_optree

This function finalizes the optree. Should be called directly after the complete optree is built. It does some additional checking which can't be done in the normal ck_xxx functions and makes the tree thread-safe.

void       finalize_optree(      OP *o)
void  Perl_finalize_optree(pTHX_ OP *o)

#forbid_outofblock_ops

NOTE: forbid_outofblock_ops is experimental and may change or be removed without notice.

Checks an optree that implements a block, to ensure there are no control-flow ops that attempt to leave the block. Any OP_RETURN is forbidden, as is any OP_GOTO. Loops are analysed, so any LOOPEX op (OP_NEXT, OP_LAST or OP_REDO) that affects a loop that contains it within the block are permitted, but those that do not are forbidden.

If any of these forbidden constructions are detected, an exception is thrown by using the op name and the blockname argument to construct a suitable message.

This function alone is not sufficient to ensure the optree does not perform any of these forbidden activities during runtime, as it might call a different function that performs a non-local LOOPEX, or a string-eval() that performs a goto, or various other things. It is intended purely as a compile-time check for those that could be detected statically. Additional runtime checks may be required depending on the circumstance it is used for.

Note currently that all OP_GOTO ops are forbidden, even in cases where they might otherwise be safe to execute. This may be permitted in a later version.

void       forbid_outofblock_ops(      OP *o,
                                       const char *blockname)
void  Perl_forbid_outofblock_ops(pTHX_ OP *o,
                                       const char *blockname)

#LINKLIST

Given the root of an optree, link the tree in execution order using the op_next pointers and return the first op executed. If this has already been done, it will not be redone, and o->op_next will be returned. If o->op_next is not already set, o should be at least an UNOP.

OP*  LINKLIST(OP *o)

#LISTOP

#LOGOP

#LOOP

Described in perlguts.

#newANONATTRSUB

Construct a nameless (anonymous) Perl subroutine, also performing some surrounding jobs.

This is the same as "newATTRSUB_x" in perlintern with its o_is_gv parameter set to FALSE, and its o parameter to NULL. For more details, see "newATTRSUB_x" in perlintern.

OP *       newANONATTRSUB(      I32 floor, OP *proto, OP *attrs,
                                OP *block)
OP *  Perl_newANONATTRSUB(pTHX_ I32 floor, OP *proto, OP *attrs,
                                OP *block)

#newANONHASH

Constructs, checks, and returns an anonymous hash op.

OP *       newANONHASH(      OP *o)
OP *  Perl_newANONHASH(pTHX_ OP *o)

#newANONLIST

Constructs, checks, and returns an anonymous list op.

OP *       newANONLIST(      OP *o)
OP *  Perl_newANONLIST(pTHX_ OP *o)

#newANONSUB

Construct a nameless (anonymous) Perl subroutine without attributes, also performing some surrounding jobs.

This is the same as "newATTRSUB_x" in perlintern with its o_is_gv parameter set to FALSE, and its o and attrs parameters to NULL. For more details, see "newATTRSUB_x" in perlintern.

OP *       newANONSUB(      I32 floor, OP *proto, OP *block)
OP *  Perl_newANONSUB(pTHX_ I32 floor, OP *proto, OP *block)

#newARGDEFELEMOP

Constructs and returns a new OP_ARGDEFELEM op which provides a defaulting expression given by expr for the signature parameter at the index given by argindex. The expression optree is consumed by this function and becomes part of the returned optree.

OP *       newARGDEFELEMOP(      I32 flags, OP *expr,
                                 I32 argindex)
OP *  Perl_newARGDEFELEMOP(pTHX_ I32 flags, OP *expr,
                                 I32 argindex)

#newASSIGNOP

Constructs, checks, and returns an assignment op. left and right supply the parameters of the assignment; they are consumed by this function and become part of the constructed op tree.

If optype is OP_ANDASSIGN, OP_ORASSIGN, or OP_DORASSIGN, then a suitable conditional optree is constructed. If optype is the opcode of a binary operator, such as OP_BIT_OR, then an op is constructed that performs the binary operation and assigns the result to the left argument. Either way, if optype is non-zero then flags has no effect.

If optype is zero, then a plain scalar or list assignment is constructed. Which type of assignment it is is automatically determined. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 or 2 is automatically set as required.

OP *       newASSIGNOP(      I32 flags, OP *left, I32 optype,
                             OP *right)
OP *  Perl_newASSIGNOP(pTHX_ I32 flags, OP *left, I32 optype,
                             OP *right)

#newATTRSUB

Construct a Perl subroutine, also performing some surrounding jobs, returning a pointer to the constructed subroutine.

This is the same as "newATTRSUB_x" in perlintern with its o_is_gv parameter set to FALSE. This means that if o is null, the new sub will be anonymous; otherwise the name will be derived from o in the way described (as with all other details) in "newATTRSUB_x" in perlintern.

CV *  newATTRSUB(I32 floor, OP *o, OP *proto, OP *attrs,
                 OP *block)

#newAVREF

Constructs, checks, and returns an arrary reference op.

OP *       newAVREF(      OP *o)
OP *  Perl_newAVREF(pTHX_ OP *o)

#newBINOP

Constructs, checks, and returns an op of any binary type. type is the opcode. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 or 2 is automatically set as required. first and last supply up to two ops to be the direct children of the binary op; they are consumed by this function and become part of the constructed op tree.

OP *       newBINOP(      I32 type, I32 flags, OP *first,
                          OP *last)
OP *  Perl_newBINOP(pTHX_ I32 type, I32 flags, OP *first,
                          OP *last)

#newCONDOP

Constructs, checks, and returns a conditional-expression (cond_expr) op. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 is automatically set. first supplies the expression selecting between the two branches, and trueop and falseop supply the branches; they are consumed by this function and become part of the constructed op tree.

OP *       newCONDOP(      I32 flags, OP *first, OP *trueop,
                           OP *falseop)
OP *  Perl_newCONDOP(pTHX_ I32 flags, OP *first, OP *trueop,
                           OP *falseop)

#newCONSTSUB

#newCONSTSUB_flags

Construct a constant subroutine, also performing some surrounding jobs. A scalar constant-valued subroutine is eligible for inlining at compile-time, and in Perl code can be created by sub FOO () { 123 }. Other kinds of constant subroutine have other treatment.

The subroutine will have an empty prototype and will ignore any arguments when called. Its constant behaviour is determined by sv. If sv is null, the subroutine will yield an empty list. If sv points to a scalar, the subroutine will always yield that scalar. If sv points to an array, the subroutine will always yield a list of the elements of that array in list context, or the number of elements in the array in scalar context. This function takes ownership of one counted reference to the scalar or array, and will arrange for the object to live as long as the subroutine does. If sv points to a scalar then the inlining assumes that the value of the scalar will never change, so the caller must ensure that the scalar is not subsequently written to. If sv points to an array then no such assumption is made, so it is ostensibly safe to mutate the array or its elements, but whether this is really supported has not been determined.

The subroutine will have CvFILE set according to PL_curcop. Other aspects of the subroutine will be left in their default state. The caller is free to mutate the subroutine beyond its initial state after this function has returned.

If name is null then the subroutine will be anonymous, with its CvGV referring to an __ANON__ glob. If name is non-null then the subroutine will be named accordingly, referenced by the appropriate glob.

name is a string, giving a sigilless symbol name. For /newCONSTSUB, name is NUL-terminated, interpreted as Latin-1.

For /newCONSTSUB_flags, name has length len bytes, hence may contain embedded NULs. It is interpreted as UTF-8 if flags has the SVf_UTF8 bit set, and Latin-1 otherwise. flags should not have bits set other than SVf_UTF8.

The name may be either qualified or unqualified. If the name is unqualified then it defaults to being in the stash specified by stash if that is non-null, or to PL_curstash if stash is null. The symbol is always added to the stash if necessary, with GV_ADDMULTI semantics.

If there is already a subroutine of the specified name, then the new sub will replace the existing one in the glob. A warning may be generated about the redefinition.

If the subroutine has one of a few special names, such as BEGIN or END, then it will be claimed by the appropriate queue for automatic running of phase-related subroutines. In this case the relevant glob will be left not containing any subroutine, even if it did contain one before. Execution of the subroutine will likely be a no-op, unless sv was a tied array or the caller modified the subroutine in some interesting way before it was executed. In the case of BEGIN, the treatment is buggy: the sub will be executed when only half built, and may be deleted prematurely, possibly causing a crash.

The function returns a pointer to the constructed subroutine. If the sub is anonymous then ownership of one counted reference to the subroutine is transferred to the caller. If the sub is named then the caller does not get ownership of a reference. In most such cases, where the sub has a non-phase name, the sub will be alive at the point it is returned by virtue of being contained in the glob that names it. A phase-named subroutine will usually be alive by virtue of the reference owned by the phase's automatic run queue. A BEGIN subroutine may have been destroyed already by the time this function returns, but currently bugs occur in that case before the caller gets control. It is the caller's responsibility to ensure that it knows which of these situations applies.

CV *       newCONSTSUB      (      HV *stash, const char *name,
                                   SV *sv)
CV *  Perl_newCONSTSUB      (pTHX_ HV *stash, const char *name,
                                   SV *sv)
CV *       newCONSTSUB_flags(      HV *stash, const char *name,
                                   STRLEN len, U32 flags, SV *sv)
CV *  Perl_newCONSTSUB_flags(pTHX_ HV *stash, const char *name,
                                   STRLEN len, U32 flags, SV *sv)

#newCVREF

Constructs, checks, and returns a code reference op.

OP *       newCVREF(      I32 flags, OP *o)
OP *  Perl_newCVREF(pTHX_ I32 flags, OP *o)

#newDEFEROP

NOTE: newDEFEROP is experimental and may change or be removed without notice.

Constructs and returns a deferred-block statement that implements the defer semantics. The block optree is consumed by this function and becomes part of the returned optree.

The flags argument carries additional flags to set on the returned op, including the op_private field.

OP *       newDEFEROP(      I32 flags, OP *block)
OP *  Perl_newDEFEROP(pTHX_ I32 flags, OP *block)

#newDEFSVOP

Constructs and returns an op to access $_.

OP *       newDEFSVOP()
OP *  Perl_newDEFSVOP(pTHX)

#newFOROP

Constructs, checks, and returns an op tree expressing a foreach loop (iteration through a list of values). This is a heavyweight loop, with structure that allows exiting the loop by last and suchlike.

sv optionally supplies the variable(s) that will be aliased to each item in turn; if null, it defaults to $_. expr supplies the list of values to iterate over. block supplies the main body of the loop, and cont optionally supplies a continue block that operates as a second half of the body. All of these optree inputs are consumed by this function and become part of the constructed op tree.

flags gives the eight bits of op_flags for the leaveloop op and, shifted up eight bits, the eight bits of op_private for the leaveloop op, except that (in both cases) some bits will be set automatically.

OP *       newFOROP(      I32 flags, OP *sv, OP *expr, OP *block,
                          OP *cont)
OP *  Perl_newFOROP(pTHX_ I32 flags, OP *sv, OP *expr, OP *block,
                          OP *cont)

#newGIVENOP

Constructs, checks, and returns an op tree expressing a given block. cond supplies the expression to whose value $_ will be locally aliased, and block supplies the body of the given construct; they are consumed by this function and become part of the constructed op tree. defsv_off must be zero (it used to identity the pad slot of lexical $_).

OP *       newGIVENOP(      OP *cond, OP *block,
                            PADOFFSET defsv_off)
OP *  Perl_newGIVENOP(pTHX_ OP *cond, OP *block,
                            PADOFFSET defsv_off)

#newGVOP

Constructs, checks, and returns an op of any type that involves an embedded reference to a GV. type is the opcode. flags gives the eight bits of op_flags. gv identifies the GV that the op should reference; calling this function does not transfer ownership of any reference to it.

OP *       newGVOP(      I32 type, I32 flags, GV *gv)
OP *  Perl_newGVOP(pTHX_ I32 type, I32 flags, GV *gv)

#newGVREF

Constructs, checks, and returns a glob reference op.

OP *       newGVREF(      I32 type, OP *o)
OP *  Perl_newGVREF(pTHX_ I32 type, OP *o)

#newHVREF

Constructs, checks, and returns a hash reference op.

OP *       newHVREF(      OP *o)
OP *  Perl_newHVREF(pTHX_ OP *o)

#newLISTOP

Constructs, checks, and returns an op of any list type. type is the opcode. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically if required. first and last supply up to two ops to be direct children of the list op; they are consumed by this function and become part of the constructed op tree.

For most list operators, the check function expects all the kid ops to be present already, so calling newLISTOP(OP_JOIN, ...) (e.g.) is not appropriate. What you want to do in that case is create an op of type OP_LIST, append more children to it, and then call "op_convert_list". See "op_convert_list" for more information.

If a compiletime-known fixed list of child ops is required, the "newLISTOPn" function can be used as a convenient shortcut, avoiding the need to create a temporary plain OP_LIST in a new variable.

OP *       newLISTOP(      I32 type, I32 flags, OP *first,
                           OP *last)
OP *  Perl_newLISTOP(pTHX_ I32 type, I32 flags, OP *first,
                           OP *last)

#newLISTOPn

Constructs, checks, and returns an op of any list type. type is the opcode. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically if required. The variable number of arguments after flags must all be OP pointers, terminated by a final NULL pointer. These will all be consumed as direct children of the list op and become part of the constructed op tree.

Do not forget to end the arguments list with a NULL pointer.

This function is useful as a shortcut to performing the sequence of newLISTOP(), op_append_elem() on each element and final op_convert_list() in the case where a compiletime-known fixed sequence of child ops is required. If a variable number of elements are required, or for splicing in an entire sub-list of child ops, see instead "newLISTOP" and "op_convert_list".

OP *       newLISTOPn(      I32 type, I32 flags, ...)
OP *  Perl_newLISTOPn(pTHX_ I32 type, I32 flags, ...)

#newLOGOP

Constructs, checks, and returns a logical (flow control) op. type is the opcode. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 is automatically set. first supplies the expression controlling the flow, and other supplies the side (alternate) chain of ops; they are consumed by this function and become part of the constructed op tree.

OP *       newLOGOP(      I32 optype, I32 flags, OP *first,
                          OP *other)
OP *  Perl_newLOGOP(pTHX_ I32 optype, I32 flags, OP *first,
                          OP *other)

#newLOOPEX

Constructs, checks, and returns a loop-exiting op (such as goto or last). type is the opcode. label supplies the parameter determining the target of the op; it is consumed by this function and becomes part of the constructed op tree.

OP *       newLOOPEX(      I32 type, OP *label)
OP *  Perl_newLOOPEX(pTHX_ I32 type, OP *label)

#newLOOPOP

Constructs, checks, and returns an op tree expressing a loop. This is only a loop in the control flow through the op tree; it does not have the heavyweight loop structure that allows exiting the loop by last and suchlike. flags gives the eight bits of op_flags for the top-level op, except that some bits will be set automatically as required. expr supplies the expression controlling loop iteration, and block supplies the body of the loop; they are consumed by this function and become part of the constructed op tree. debuggable is currently unused and should always be 1.

OP *       newLOOPOP(      I32 flags, I32 debuggable, OP *expr,
                           OP *block)
OP *  Perl_newLOOPOP(pTHX_ I32 flags, I32 debuggable, OP *expr,
                           OP *block)

#newMETHOP

Constructs, checks, and returns an op of method type with a method name evaluated at runtime. type is the opcode. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 is automatically set. dynamic_meth supplies an op which evaluates method name; it is consumed by this function and become part of the constructed op tree. Supported optypes: OP_METHOD.

OP *       newMETHOP(      I32 type, I32 flags, OP *dynamic_meth)
OP *  Perl_newMETHOP(pTHX_ I32 type, I32 flags, OP *dynamic_meth)

#newMETHOP_named

Constructs, checks, and returns an op of method type with a constant method name. type is the opcode. flags gives the eight bits of op_flags, and, shifted up eight bits, the eight bits of op_private. const_meth supplies a constant method name; it must be a shared COW string. Supported optypes: OP_METHOD_NAMED.

OP *       newMETHOP_named(      I32 type, I32 flags,
                                 SV * const_meth)
OP *  Perl_newMETHOP_named(pTHX_ I32 type, I32 flags,
                                 SV * const_meth)

#newNULLLIST

Constructs, checks, and returns a new stub op, which represents an empty list expression.

OP *       newNULLLIST()
OP *  Perl_newNULLLIST(pTHX)

#newOP

Constructs, checks, and returns an op of any base type (any type that has no extra fields). type is the opcode. flags gives the eight bits of op_flags, and, shifted up eight bits, the eight bits of op_private.

OP *       newOP(      I32 optype, I32 flags)
OP *  Perl_newOP(pTHX_ I32 optype, I32 flags)

#newPADOP

Constructs, checks, and returns an op of any type that involves a reference to a pad element. type is the opcode. flags gives the eight bits of op_flags. A pad slot is automatically allocated, and is populated with sv; this function takes ownership of one reference to it.

This function only exists if Perl has been compiled to use ithreads.

OP *       newPADOP(      I32 type, I32 flags, SV *sv)
OP *  Perl_newPADOP(pTHX_ I32 type, I32 flags, SV *sv)

#newPMOP

Constructs, checks, and returns an op of any pattern matching type. type is the opcode. flags gives the eight bits of op_flags and, shifted up eight bits, the eight bits of op_private.

OP *       newPMOP(      I32 type, I32 flags)
OP *  Perl_newPMOP(pTHX_ I32 type, I32 flags)

#newPVOP

Constructs, checks, and returns an op of any type that involves an embedded C-level pointer (PV). type is the opcode. flags gives the eight bits of op_flags. pv supplies the C-level pointer. Depending on the op type, the memory referenced by pv may be freed when the op is destroyed. If the op is of a freeing type, pv must have been allocated using PerlMemShared_malloc.

OP *       newPVOP(      I32 type, I32 flags, char *pv)
OP *  Perl_newPVOP(pTHX_ I32 type, I32 flags, char *pv)

#newRANGE

Constructs and returns a range op, with subordinate flip and flop ops. flags gives the eight bits of op_flags for the flip op and, shifted up eight bits, the eight bits of op_private for both the flip and range ops, except that the bit with value 1 is automatically set. left and right supply the expressions controlling the endpoints of the range; they are consumed by this function and become part of the constructed op tree.

OP *       newRANGE(      I32 flags, OP *left, OP *right)
OP *  Perl_newRANGE(pTHX_ I32 flags, OP *left, OP *right)

#newSLICEOP

Constructs, checks, and returns an lslice (list slice) op. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 or 2 is automatically set as required. listval and subscript supply the parameters of the slice; they are consumed by this function and become part of the constructed op tree.

OP *       newSLICEOP(      I32 flags, OP *subscript, OP *listop)
OP *  Perl_newSLICEOP(pTHX_ I32 flags, OP *subscript, OP *listop)

#newSTATEOP

Constructs a state op (COP). The state op is normally a nextstate op, but will be a dbstate op if debugging is enabled for currently-compiled code. The state op is populated from PL_curcop (or PL_compiling). If label is non-null, it supplies the name of a label to attach to the state op; this function takes ownership of the memory pointed at by label, and will free it. flags gives the eight bits of op_flags for the state op.

If o is null, the state op is returned. Otherwise the state op is combined with o into a lineseq list op, which is returned. o is consumed by this function and becomes part of the returned op tree.

OP *       newSTATEOP(      I32 flags, char *label, OP *o)
OP *  Perl_newSTATEOP(pTHX_ I32 flags, char *label, OP *o)

#newSUB

Construct a Perl subroutine without attributes, and also performing some surrounding jobs, returning a pointer to the constructed subroutine.

This is the same as "newATTRSUB_x" in perlintern with its o_is_gv parameter set to FALSE, and its attrs parameter to NULL. This means that if o is null, the new sub will be anonymous; otherwise the name will be derived from o in the way described (as with all other details) in "newATTRSUB_x" in perlintern.

CV *       newSUB(      I32 floor, OP *o, OP *proto, OP *block)
CV *  Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)

#newSVOP

Constructs, checks, and returns an op of any type that involves an embedded SV. type is the opcode. flags gives the eight bits of op_flags. sv gives the SV to embed in the op; this function takes ownership of one reference to it.

OP *       newSVOP(      I32 type, I32 flags, SV *sv)
OP *  Perl_newSVOP(pTHX_ I32 type, I32 flags, SV *sv)

#newSVREF

Constructs, checks, and returns a scalar reference op.

OP *       newSVREF(      OP *o)
OP *  Perl_newSVREF(pTHX_ OP *o)

#newTRYCATCHOP

NOTE: newTRYCATCHOP is experimental and may change or be removed without notice.

Constructs and returns a conditional execution statement that implements the try/catch semantics. First the op tree in tryblock is executed, inside a context that traps exceptions. If an exception occurs then the optree in catchblock is executed, with the trapped exception set into the lexical variable given by catchvar (which must be an op of type OP_PADSV). All the optrees are consumed by this function and become part of the returned op tree.

The flags argument is currently ignored.

OP *       newTRYCATCHOP(      I32 flags, OP *tryblock,
                               OP *catchvar, OP *catchblock)
OP *  Perl_newTRYCATCHOP(pTHX_ I32 flags, OP *tryblock,
                               OP *catchvar, OP *catchblock)

#newUNOP

Constructs, checks, and returns an op of any unary type. type is the opcode. flags gives the eight bits of op_flags, except that OPf_KIDS will be set automatically if required, and, shifted up eight bits, the eight bits of op_private, except that the bit with value 1 is automatically set. first supplies an optional op to be the direct child of the unary op; it is consumed by this function and become part of the constructed op tree.

OP *       newUNOP(      I32 type, I32 flags, OP *first)
OP *  Perl_newUNOP(pTHX_ I32 type, I32 flags, OP *first)

#newUNOP_AUX

Similar to newUNOP, but creates an UNOP_AUX struct instead, with op_aux initialised to aux

OP *       newUNOP_AUX(      I32 type, I32 flags, OP *first,
                             UNOP_AUX_item *aux)
OP *  Perl_newUNOP_AUX(pTHX_ I32 type, I32 flags, OP *first,
                             UNOP_AUX_item *aux)

#newWHENOP

Constructs, checks, and returns an op tree expressing a when block. cond supplies the test expression, and block supplies the block that will be executed if the test evaluates to true; they are consumed by this function and become part of the constructed op tree. cond will be interpreted DWIMically, often as a comparison against $_, and may be null to generate a default block.

OP *       newWHENOP(      OP *cond, OP *block)
OP *  Perl_newWHENOP(pTHX_ OP *cond, OP *block)

#newWHILEOP

Constructs, checks, and returns an op tree expressing a while loop. This is a heavyweight loop, with structure that allows exiting the loop by last and suchlike.

loop is an optional preconstructed enterloop op to use in the loop; if it is null then a suitable op will be constructed automatically. expr supplies the loop's controlling expression. block supplies the main body of the loop, and cont optionally supplies a continue block that operates as a second half of the body. All of these optree inputs are consumed by this function and become part of the constructed op tree.

flags gives the eight bits of op_flags for the leaveloop op and, shifted up eight bits, the eight bits of op_private for the leaveloop op, except that (in both cases) some bits will be set automatically. debuggable is currently unused and should always be 1. has_my can be supplied as true to force the loop body to be enclosed in its own scope.

OP *       newWHILEOP(      I32 flags, I32 debuggable,
                            LOOP *loop, OP *expr, OP *block,
                            OP *cont, I32 has_my)
OP *  Perl_newWHILEOP(pTHX_ I32 flags, I32 debuggable,
                            LOOP *loop, OP *expr, OP *block,
                            OP *cont, I32 has_my)

#newXS

Used by xsubpp to hook up XSUBs as Perl subs. filename needs to be static storage, as it is used directly as CvFILE(), without a copy being made.

#OA_BASEOP

#OA_BINOP

#OA_COP

#OA_LISTOP

#OA_LOGOP

#OA_LOOP

#OA_PADOP

#OA_PMOP

#OA_PVOP_OR_SVOP

#OA_SVOP

#OA_UNOP

#OP

Described in perlguts.

#op_append_elem

Append an item to the list of ops contained directly within a list-type op, returning the lengthened list. first is the list-type op, and last is the op to append to the list. optype specifies the intended opcode for the list. If first is not already a list of the right type, it will be upgraded into one. If either first or last is null, the other is returned unchanged.

OP *       op_append_elem(      I32 optype, OP *first, OP *last)
OP *  Perl_op_append_elem(pTHX_ I32 optype, OP *first, OP *last)

#op_append_list

Concatenate the lists of ops contained directly within two list-type ops, returning the combined list. first and last are the list-type ops to concatenate. optype specifies the intended opcode for the list. If either first or last is not already a list of the right type, it will be upgraded into one. If either first or last is null, the other is returned unchanged.

OP *       op_append_list(      I32 optype, OP *first, OP *last)
OP *  Perl_op_append_list(pTHX_ I32 optype, OP *first, OP *last)

#OP_CLASS

Return the class of the provided OP: that is, which of the *OP structures it uses. For core ops this currently gets the information out of PL_opargs, which does not always accurately reflect the type used; in v5.26 onwards, see also the function "op_class" which can do a better job of determining the used type.

For custom ops the type is returned from the registration, and it is up to the registree to ensure it is accurate. The value returned will be one of the OA_* constants from op.h.

U32  OP_CLASS(OP *o)

#op_contextualize

Applies a syntactic context to an op tree representing an expression. o is the op tree, and context must be G_SCALAR, G_LIST, or G_VOID to specify the context to apply. The modified op tree is returned.

OP *       op_contextualize(      OP *o, I32 context)
OP *  Perl_op_contextualize(pTHX_ OP *o, I32 context)

#op_convert_list

Converts o into a list op if it is not one already, and then converts it into the specified type, calling its check function, allocating a target if it needs one, and folding constants.

A list-type op is usually constructed one kid at a time via newLISTOP, op_prepend_elem and op_append_elem. Then finally it is passed to op_convert_list to make it the right type.

OP *       op_convert_list(      I32 optype, I32 flags, OP *o)
OP *  Perl_op_convert_list(pTHX_ I32 optype, I32 flags, OP *o)

#OP_DESC

Return a short description of the provided OP.

const char *  OP_DESC(OP *o)

#op_force_list

Promotes o and any siblings to be an OP_LIST if it is not already. If a new OP_LIST op was created, its first child will be OP_PUSHMARK. The returned node itself will be nulled, leaving only its children.

This is often what you want to do before putting the optree into list context; as

o = op_contextualize(op_force_list(o), G_LIST);

OP *       op_force_list(      OP *o)
OP *  Perl_op_force_list(pTHX_ OP *o)

#op_free

Free an op and its children. Only use this when an op is no longer linked to from any optree.

Remember that any op with OPf_KIDS set is expected to have a valid op_first pointer. If you are attempting to free an op but preserve its child op, make sure to clear that flag before calling op_free(). For example:

OP *kid = o->op_first; o->op_first = NULL;
o->op_flags &= ~OPf_KIDS;
op_free(o);

void       op_free(      OP *arg)
void  Perl_op_free(pTHX_ OP *arg)

#op_linklist

This function is the implementation of the "LINKLIST" macro. It should not be called directly.

OP *       op_linklist(      OP *o)
OP *  Perl_op_linklist(pTHX_ OP *o)

#op_lvalue

NOTE: op_lvalue is experimental and may change or be removed without notice.

Propagate lvalue ("modifiable") context to an op and its children. type represents the context type, roughly based on the type of op that would do the modifying, although local() is represented by OP_NULL, because it has no op type of its own (it is signalled by a flag on the lvalue op).

This function detects things that can't be modified, such as $x+1, and generates errors for them. For example, $x+1 = 2 would cause it to be called with an op of type OP_ADD and a type argument of OP_SASSIGN.

It also flags things that need to behave specially in an lvalue context, such as $$x = 5 which might have to vivify a reference in $x.

OP *  op_lvalue(OP *o, I32 type)

#OP_NAME

Return the name of the provided OP. For core ops this looks up the name from the op_type; for custom ops from the op_ppaddr.

const char *  OP_NAME(OP *o)

#op_null

Neutralizes an op when it is no longer needed, but is still linked to from other ops.

void       op_null(      OP *o)
void  Perl_op_null(pTHX_ OP *o)

#op_parent

Returns the parent OP of o, if it has a parent. Returns NULL otherwise.

OP *       op_parent(OP *o)
OP *  Perl_op_parent(OP *o)

#op_prepend_elem

Prepend an item to the list of ops contained directly within a list-type op, returning the lengthened list. first is the op to prepend to the list, and last is the list-type op. optype specifies the intended opcode for the list. If last is not already a list of the right type, it will be upgraded into one. If either first or last is null, the other is returned unchanged.

OP *       op_prepend_elem(      I32 optype, OP *first, OP *last)
OP *  Perl_op_prepend_elem(pTHX_ I32 optype, OP *first, OP *last)

#op_scope

NOTE: op_scope is experimental and may change or be removed without notice.

Wraps up an op tree with some additional ops so that at runtime a dynamic scope will be created. The original ops run in the new dynamic scope, and then, provided that they exit normally, the scope will be unwound. The additional ops used to create and unwind the dynamic scope will normally be an enter/leave pair, but a scope op may be used instead if the ops are simple enough to not need the full dynamic scope structure.

OP *       op_scope(      OP *o)
OP *  Perl_op_scope(pTHX_ OP *o)

#op_sibling_splice

A general function for editing the structure of an existing chain of op_sibling nodes. By analogy with the perl-level splice() function, allows you to delete zero or more sequential nodes, replacing them with zero or more different nodes. Performs the necessary op_first/op_last housekeeping on the parent node and op_sibling manipulation on the children. The last deleted node will be marked as the last node by updating the op_sibling/op_sibparent or op_moresib field as appropriate.

Note that op_next is not manipulated, and nodes are not freed; that is the responsibility of the caller. It also won't create a new list op for an empty list etc; use higher-level functions like op_append_elem() for that.

parent is the parent node of the sibling chain. It may passed as NULL if the splicing doesn't affect the first or last op in the chain.

start is the node preceding the first node to be spliced. Node(s) following it will be deleted, and ops will be inserted after it. If it is NULL, the first node onwards is deleted, and nodes are inserted at the beginning.

del_count is the number of nodes to delete. If zero, no nodes are deleted. If -1 or greater than or equal to the number of remaining kids, all remaining kids are deleted.

insert is the first of a chain of nodes to be inserted in place of the nodes. If NULL, no nodes are inserted.

The head of the chain of deleted ops is returned, or NULL if no ops were deleted.

For example:

action                    before      after         returns
------                    -----       -----         -------
                          P           P
splice(P, A, 2, X-Y-Z)    |           |             B-C
                          A-B-C-D     A-X-Y-Z-D
                          P           P
splice(P, NULL, 1, X-Y)   |           |             A
                          A-B-C-D     X-Y-B-C-D
                          P           P
splice(P, NULL, 3, NULL)  |           |             A-B-C
                          A-B-C-D     D
                          P           P
splice(P, B, 0, X-Y)      |           |             NULL
                          A-B-C-D     A-B-X-Y-C-D

For lower-level direct manipulation of op_sibparent and op_moresib, see "OpMORESIB_set", "OpLASTSIB_set", "OpMAYBESIB_set".

OP *       op_sibling_splice(      OP *parent, OP *start,
                                   int del_count, OP *insert)
OP *  Perl_op_sibling_splice(pTHX_ OP *parent, OP *start,
                                   int del_count, OP *insert)

#OP_TYPE_IS

Returns true if the given OP is not a NULL pointer and if it is of the given type.

The negation of this macro, OP_TYPE_ISNT is also available as well as OP_TYPE_IS_NN and OP_TYPE_ISNT_NN which elide the NULL pointer check.

bool  OP_TYPE_IS(OP *o, Optype type)

#OP_TYPE_IS_OR_WAS

Returns true if the given OP is not a NULL pointer and if it is of the given type or used to be before being replaced by an OP of type OP_NULL.

The negation of this macro, OP_TYPE_ISNT_AND_WASNT is also available as well as OP_TYPE_IS_OR_WAS_NN and OP_TYPE_ISNT_AND_WASNT_NN which elide the NULL pointer check.

bool  OP_TYPE_IS_OR_WAS(OP *o, Optype type)

#op_wrap_finally

NOTE: op_wrap_finally is experimental and may change or be removed without notice.

Wraps the given block optree fragment in its own scoped block, arranging for the finally optree fragment to be invoked when leaving that block for any reason. Both optree fragments are consumed and the combined result is returned.

OP *       op_wrap_finally(      OP *block, OP *finally)
OP *  Perl_op_wrap_finally(pTHX_ OP *block, OP *finally)

#opcode

An enum of all the legal Perl opcodes, defined in opnames.h

#OpHAS_SIBLING

Returns true if o has a sibling

bool  OpHAS_SIBLING(OP *o)

#OpLASTSIB_set

Marks o as having no further siblings and marks o as having the specified parent. See also "OpMORESIB_set" and OpMAYBESIB_set. For a higher-level interface, see "op_sibling_splice".

void  OpLASTSIB_set(OP *o, OP *parent)

#OpMAYBESIB_set

Conditionally does OpMORESIB_set or OpLASTSIB_set depending on whether sib is non-null. For a higher-level interface, see "op_sibling_splice".

void  OpMAYBESIB_set(OP *o, OP *sib, OP *parent)

#OpMORESIB_set

Sets the sibling of o to the non-zero value sib. See also "OpLASTSIB_set" and "OpMAYBESIB_set". For a higher-level interface, see "op_sibling_splice".

void  OpMORESIB_set(OP *o, OP *sib)

#OpSIBLING

Returns the sibling of o, or NULL if there is no sibling

OP*  OpSIBLING(OP *o)

#optimize_optree

This function applies some optimisations to the optree in top-down order. It is called before the peephole optimizer, which processes ops in execution order. Note that finalize_optree() also does a top-down scan, but is called *after* the peephole optimizer.

void       optimize_optree(      OP *o)
void  Perl_optimize_optree(pTHX_ OP *o)

#peep_t

#Perl_cpeep_t

Described in perlguts.

#PL_opfreehook

When non-NULL, the function pointed by this variable will be called each time an OP is freed with the corresponding OP as the argument. This allows extensions to free any extra attribute they have locally attached to an OP. It is also assured to first fire for the parent OP and then for its kids.

When you replace this variable, it is considered a good practice to store the possibly previously installed hook and that you recall it inside your own.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

Perl_ophook_t  PL_opfreehook

#PL_peepp

Pointer to the per-subroutine peephole optimiser. This is a function that gets called at the end of compilation of a Perl subroutine (or equivalently independent piece of Perl code) to perform fixups of some ops and to perform small-scale optimisations. The function is called once for each subroutine that is compiled, and is passed, as sole parameter, a pointer to the op that is the entry point to the subroutine. It modifies the op tree in place.

The peephole optimiser should never be completely replaced. Rather, add code to it by wrapping the existing optimiser. The basic way to do this can be seen in "Compile pass 3: peephole optimization" in perlguts. If the new code wishes to operate on ops throughout the subroutine's structure, rather than just at the top level, it is likely to be more convenient to wrap the "PL_rpeepp" hook.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

peep_t  PL_peepp

#PL_rpeepp

Pointer to the recursive peephole optimiser. This is a function that gets called at the end of compilation of a Perl subroutine (or equivalently independent piece of Perl code) to perform fixups of some ops and to perform small-scale optimisations. The function is called once for each chain of ops linked through their op_next fields; it is recursively called to handle each side chain. It is passed, as sole parameter, a pointer to the op that is at the head of the chain. It modifies the op tree in place.

The peephole optimiser should never be completely replaced. Rather, add code to it by wrapping the existing optimiser. The basic way to do this can be seen in "Compile pass 3: peephole optimization" in perlguts. If the new code wishes to operate only on ops at a subroutine's top level, rather than throughout the structure, it is likely to be more convenient to wrap the "PL_peepp" hook.

On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

peep_t  PL_rpeepp

#PMOP

Described in perlguts.

#rv2cv_op_cv

Examines an op, which is expected to identify a subroutine at runtime, and attempts to determine at compile time which subroutine it identifies. This is normally used during Perl compilation to determine whether a prototype can be applied to a function call. cvop is the op being considered, normally an rv2cv op. A pointer to the identified subroutine is returned, if it could be determined statically, and a null pointer is returned if it was not possible to determine statically.

Currently, the subroutine can be identified statically if the RV that the rv2cv is to operate on is provided by a suitable gv or const op. A gv op is suitable if the GV's CV slot is populated. A const op is suitable if the constant value must be an RV pointing to a CV. Details of this process may change in future versions of Perl. If the rv2cv op has the OPpENTERSUB_AMPER flag set then no attempt is made to identify the subroutine statically: this flag is used to suppress compile-time magic on a subroutine call, forcing it to use default runtime behaviour.

If flags has the bit RV2CVOPCV_MARK_EARLY set, then the handling of a GV reference is modified. If a GV was examined and its CV slot was found to be empty, then the gv op has the OPpEARLY_CV flag set. If the op is not optimised away, and the CV slot is later populated with a subroutine having a prototype, that flag eventually triggers the warning "called too early to check prototype".

If flags has the bit RV2CVOPCV_RETURN_NAME_GV set, then instead of returning a pointer to the subroutine it returns a pointer to the GV giving the most appropriate name for the subroutine in this context. Normally this is just the CvGV of the subroutine, but for an anonymous (CvANON) subroutine that is referenced through a GV it will be the referencing GV. The resulting GV* is cast to CV* to be returned. A null pointer is returned as usual if there is no statically-determinable subroutine.

CV *       rv2cv_op_cv(      OP *cvop, U32 flags)
CV *  Perl_rv2cv_op_cv(pTHX_ OP *cvop, U32 flags)

#UNOP

#XOP

Described in perlguts.

#Pack and Unpack

#packlist

The engine implementing pack() Perl function.

void       packlist(      SV *cat, const char *pat,
                          const char *patend, SV **beglist,
                          SV **endlist)
void  Perl_packlist(pTHX_ SV *cat, const char *pat,
                          const char *patend, SV **beglist,
                          SV **endlist)

#unpackstring

The engine implementing the unpack() Perl function.

Using the template pat..patend, this function unpacks the string s..strend into a number of mortal SVs, which it pushes onto the perl argument (@_) stack (so you will need to issue a PUTBACK before and SPAGAIN after the call to this function). It returns the number of pushed elements.

The strend and patend pointers should point to the byte following the last character of each string.

Although this function returns its values on the perl argument stack, it doesn't take any parameters from that stack (and thus in particular there's no need to do a PUSHMARK before calling it, unlike "call_pv" for example).

SSize_t       unpackstring(      const char *pat,
                                 const char *patend,
                                 const char *s,
                                 const char *strend, U32 flags)
SSize_t  Perl_unpackstring(pTHX_ const char *pat,
                                 const char *patend,
                                 const char *s,
                                 const char *strend, U32 flags)

#Pad Data Structures

#CvPADLIST

NOTE: CvPADLIST is experimental and may change or be removed without notice.

CV's can have CvPADLIST(cv) set to point to a PADLIST. This is the CV's scratchpad, which stores lexical variables and opcode temporary and per-thread values.

For these purposes "formats" are a kind-of CV; eval""s are too (except they're not callable at will and are always thrown away after the eval"" is done executing). Require'd files are simply evals without any outer lexical scope.

XSUBs do not have a CvPADLIST. dXSTARG fetches values from PL_curpad, but that is really the callers pad (a slot of which is allocated by every entersub). Do not get or set CvPADLIST if a CV is an XSUB (as determined by CvISXSUB()), CvPADLIST slot is reused for a different internal purpose in XSUBs.

The PADLIST has a C array where pads are stored.

The 0th entry of the PADLIST is a PADNAMELIST which represents the "names" or rather the "static type information" for lexicals. The individual elements of a PADNAMELIST are PADNAMEs. Future refactorings might stop the PADNAMELIST from being stored in the PADLIST's array, so don't rely on it. See "PadlistNAMES".

The CvDEPTH'th entry of a PADLIST is a PAD (an AV) which is the stack frame at that depth of recursion into the CV. The 0th slot of a frame AV is an AV which is @_. Other entries are storage for variables and op targets.

Iterating over the PADNAMELIST iterates over all possible pad items. Pad slots for targets (SVs_PADTMP) and GVs end up having &PL_padname_undef "names", while slots for constants have &PL_padname_const "names" (see "pad_alloc"). That &PL_padname_undef and &PL_padname_const are used is an implementation detail subject to change. To test for them, use !PadnamePV(name) and PadnamePV(name) && !PadnameLEN(name), respectively.

Only my/our variable slots get valid names. The rest are op targets/GVs/constants which are statically allocated or resolved at compile time. These don't have names by which they can be looked up from Perl code at run time through eval"" the way my/our variables can be. Since they can't be looked up by "name" but only by their index allocated at compile time (which is usually in PL_op->op_targ), wasting a name SV for them doesn't make sense.

The pad names in the PADNAMELIST have their PV holding the name of the variable. The COP_SEQ_RANGE_LOW and _HIGH fields form a range (low+1..high inclusive) of cop_seq numbers for which the name is valid. During compilation, these fields may hold the special value PERL_PADSEQ_INTRO to indicate various stages:

COP_SEQ_RANGE_LOW        _HIGH
-----------------        -----
PERL_PADSEQ_INTRO            0   variable not yet introduced:
                                 { my ($x
valid-seq#   PERL_PADSEQ_INTRO   variable in scope:
                                 { my ($x);
valid-seq#          valid-seq#   compilation of scope complete:
                                 { my ($x); .... }

When a lexical var hasn't yet been introduced, it already exists from the perspective of duplicate declarations, but not for variable lookups, e.g.

my ($x, $x); # '"my" variable $x masks earlier declaration'
my $x = $x;  # equal to my $x = $::x;

For typed lexicals PadnameTYPE points at the type stash. For our lexicals, PadnameOURSTASH points at the stash of the associated global (so that duplicate our declarations in the same package can be detected). PadnameGEN is sometimes used to store the generation number during compilation.

If PadnameOUTER is set on the pad name, then that slot in the frame AV is a REFCNT'ed reference to a lexical from "outside". Such entries are sometimes referred to as 'fake'. In this case, the name does not use 'low' and 'high' to store a cop_seq range, since it is in scope throughout. Instead 'high' stores some flags containing info about the real lexical (is it declared in an anon, and is it capable of being instantiated multiple times?), and for fake ANONs, 'low' contains the index within the parent's pad where the lexical's value is stored, to make cloning quicker.

If the 'name' is & the corresponding entry in the PAD is a CV representing a possible closure.

Note that formats are treated as anon subs, and are cloned each time write is called (if necessary).

The flag SVs_PADSTALE is cleared on lexicals each time the my() is executed, and set on scope exit. This allows the "Variable $x is not available" warning to be generated in evals, such as

{ my $x = 1; sub f { eval '$x'} } f();

For state vars, SVs_PADSTALE is overloaded to mean 'not yet initialised', but this internal state is stored in a separate pad entry.

PADLIST *  CvPADLIST(CV *cv)

#pad_add_name_pvs

Exactly like "pad_add_name_pvn", but takes a literal string instead of a string/length pair.

PADOFFSET  pad_add_name_pvs("name", U32 flags, HV *typestash,
                            HV *ourstash)

#pad_new

Create a new padlist, updating the global variables for the currently-compiling padlist to point to the new padlist. The following flags can be OR'ed together:

padnew_CLONE	this pad is for a cloned CV
padnew_SAVE		save old globals on the save stack
padnew_SAVESUB	also save extra stuff for start of sub

PADLIST *       pad_new(      int flags)
PADLIST *  Perl_pad_new(pTHX_ int flags)

#PadARRAY

NOTE: PadARRAY is experimental and may change or be removed without notice.

The C array of pad entries.

SV **  PadARRAY(PAD * pad)

#PadlistARRAY

NOTE: PadlistARRAY is experimental and may change or be removed without notice.

The C array of a padlist, containing the pads. Only subscript it with numbers >= 1, as the 0th entry is not guaranteed to remain usable.

PAD **  PadlistARRAY(PADLIST * padlist)

#PadlistMAX

NOTE: PadlistMAX is experimental and may change or be removed without notice.

The index of the last allocated space in the padlist. Note that the last pad may be in an earlier slot. Any entries following it will be NULL in that case.

SSize_t  PadlistMAX(PADLIST * padlist)

#PadlistNAMES

NOTE: PadlistNAMES is experimental and may change or be removed without notice.

The names associated with pad entries.

PADNAMELIST *  PadlistNAMES(PADLIST * padlist)

#PadlistNAMESARRAY

NOTE: PadlistNAMESARRAY is experimental and may change or be removed without notice.

The C array of pad names.

PADNAME **  PadlistNAMESARRAY(PADLIST * padlist)

#PadlistNAMESMAX

NOTE: PadlistNAMESMAX is experimental and may change or be removed without notice.

The index of the last pad name.

SSize_t  PadlistNAMESMAX(PADLIST * padlist)

#PadlistREFCNT

NOTE: PadlistREFCNT is experimental and may change or be removed without notice.

The reference count of the padlist. Currently this is always 1.

U32  PadlistREFCNT(PADLIST * padlist)

#PadMAX

NOTE: PadMAX is experimental and may change or be removed without notice.

The index of the last pad entry.

SSize_t  PadMAX(PAD * pad)

#PadnameLEN

NOTE: PadnameLEN is experimental and may change or be removed without notice.

The length of the name.

STRLEN  PadnameLEN(PADNAME * pn)

#PadnamelistARRAY

NOTE: PadnamelistARRAY is experimental and may change or be removed without notice.

The C array of pad names.

PADNAME **  PadnamelistARRAY(PADNAMELIST * pnl)

#PadnamelistMAX

NOTE: PadnamelistMAX is experimental and may change or be removed without notice.

The index of the last pad name.

SSize_t  PadnamelistMAX(PADNAMELIST * pnl)

#PadnamelistREFCNT

NOTE: PadnamelistREFCNT is experimental and may change or be removed without notice.

The reference count of the pad name list.

SSize_t  PadnamelistREFCNT(PADNAMELIST * pnl)

#PadnamelistREFCNT_dec

NOTE: PadnamelistREFCNT_dec is experimental and may change or be removed without notice.

Lowers the reference count of the pad name list.

void  PadnamelistREFCNT_dec(PADNAMELIST * pnl)

#PadnamePV

NOTE: PadnamePV is experimental and may change or be removed without notice.

The name stored in the pad name struct. This returns NULL for a target slot.

char *  PadnamePV(PADNAME * pn)

#PadnameREFCNT

NOTE: PadnameREFCNT is experimental and may change or be removed without notice.

The reference count of the pad name.

SSize_t  PadnameREFCNT(PADNAME * pn)

#PadnameREFCNT_dec

NOTE: PadnameREFCNT_dec is experimental and may change or be removed without notice.

Lowers the reference count of the pad name.

void  PadnameREFCNT_dec(PADNAME * pn)

#PadnameREFCNT_inc

NOTE: PadnameREFCNT_inc is experimental and may change or be removed without notice.

Increases the reference count of the pad name. Returns the pad name itself.

PADNAME *  PadnameREFCNT_inc(PADNAME * pn)

#PadnameSV

NOTE: PadnameSV is experimental and may change or be removed without notice.

Returns the pad name as a mortal SV.

SV *  PadnameSV(PADNAME * pn)

#PadnameUTF8

NOTE: PadnameUTF8 is experimental and may change or be removed without notice.

Whether PadnamePV is in UTF-8. Currently, this is always true.

bool  PadnameUTF8(PADNAME * pn)

#PL_comppad

NOTE: PL_comppad is experimental and may change or be removed without notice.

During compilation, this points to the array containing the values part of the pad for the currently-compiling code. (At runtime a CV may have many such value arrays; at compile time just one is constructed.) At runtime, this points to the array containing the currently-relevant values for the pad for the currently-executing code.

#PL_comppad_name

NOTE: PL_comppad_name is experimental and may change or be removed without notice.

During compilation, this points to the array containing the names part of the pad for the currently-compiling code.

#PL_curpad

NOTE: PL_curpad is experimental and may change or be removed without notice.

Points directly to the body of the "PL_comppad" array. (I.e., this is PadARRAY(PL_comppad).)

#SVs_PADMY

#SVs_PADTMP

DEPRECATED! It is planned to remove SVs_PADMY from a future release of Perl. Do not use it for new code; remove it from existing code.

Described in perlguts.

#Password and Group access

#GRPASSWD

This symbol, if defined, indicates to the C program that struct group in grp.h contains gr_passwd.

#HAS_ENDGRENT

This symbol, if defined, indicates that the getgrent routine is available for finalizing sequential access of the group database.

#HAS_ENDGRENT_R

This symbol, if defined, indicates that the endgrent_r routine is available to endgrent re-entrantly.

#HAS_ENDPWENT

This symbol, if defined, indicates that the endpwent routine is available for finalizing sequential access of the passwd database.

#HAS_ENDPWENT_R

This symbol, if defined, indicates that the endpwent_r routine is available to endpwent re-entrantly.

#HAS_GETGRENT

This symbol, if defined, indicates that the getgrent routine is available for sequential access of the group database.

#HAS_GETGRENT_R

This symbol, if defined, indicates that the getgrent_r routine is available to getgrent re-entrantly.

#HAS_GETPWENT

This symbol, if defined, indicates that the getpwent routine is available for sequential access of the passwd database. If this is not available, the older getpw() function may be available.

#HAS_GETPWENT_R

This symbol, if defined, indicates that the getpwent_r routine is available to getpwent re-entrantly.

#HAS_SETGRENT

This symbol, if defined, indicates that the setgrent routine is available for initializing sequential access of the group database.

#HAS_SETGRENT_R

This symbol, if defined, indicates that the setgrent_r routine is available to setgrent re-entrantly.

#HAS_SETPWENT

This symbol, if defined, indicates that the setpwent routine is available for initializing sequential access of the passwd database.

#HAS_SETPWENT_R

This symbol, if defined, indicates that the setpwent_r routine is available to setpwent re-entrantly.

#PWAGE

This symbol, if defined, indicates to the C program that struct passwd contains pw_age.

#PWCHANGE

This symbol, if defined, indicates to the C program that struct passwd contains pw_change.

#PWCLASS

This symbol, if defined, indicates to the C program that struct passwd contains pw_class.

#PWCOMMENT

This symbol, if defined, indicates to the C program that struct passwd contains pw_comment.

#PWEXPIRE

This symbol, if defined, indicates to the C program that struct passwd contains pw_expire.

#PWGECOS

This symbol, if defined, indicates to the C program that struct passwd contains pw_gecos.

#PWPASSWD

This symbol, if defined, indicates to the C program that struct passwd contains pw_passwd.

#PWQUOTA

This symbol, if defined, indicates to the C program that struct passwd contains pw_quota.

#Paths to system commands

#CSH

This symbol, if defined, contains the full pathname of csh.

#LOC_SED

This symbol holds the complete pathname to the sed program.

#SH_PATH

This symbol contains the full pathname to the shell used on this on this system to execute Bourne shell scripts. Usually, this will be /bin/sh, though it's possible that some systems will have /bin/ksh, /bin/pdksh, /bin/ash, /bin/bash, or even something such as D:/bin/sh.exe.

#Prototype information

#CRYPT_R_PROTO

This symbol encodes the prototype of crypt_r. It is zero if d_crypt_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_crypt_r is defined.

#CTERMID_R_PROTO

This symbol encodes the prototype of ctermid_r. It is zero if d_ctermid_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_ctermid_r is defined.

#DRAND48_R_PROTO

This symbol encodes the prototype of drand48_r. It is zero if d_drand48_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_drand48_r is defined.

#ENDGRENT_R_PROTO

This symbol encodes the prototype of endgrent_r. It is zero if d_endgrent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_endgrent_r is defined.

#ENDHOSTENT_R_PROTO

This symbol encodes the prototype of endhostent_r. It is zero if d_endhostent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_endhostent_r is defined.

#ENDNETENT_R_PROTO

This symbol encodes the prototype of endnetent_r. It is zero if d_endnetent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_endnetent_r is defined.

#ENDPROTOENT_R_PROTO

This symbol encodes the prototype of endprotoent_r. It is zero if d_endprotoent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_endprotoent_r is defined.

#ENDPWENT_R_PROTO

This symbol encodes the prototype of endpwent_r. It is zero if d_endpwent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_endpwent_r is defined.

#ENDSERVENT_R_PROTO

This symbol encodes the prototype of endservent_r. It is zero if d_endservent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_endservent_r is defined.

#GDBM_NDBM_H_USES_PROTOTYPES

This symbol, if defined, indicates that <gdbm-ndbm.h> uses real ANSI C prototypes instead of K&R style function declarations without any parameter information. While ANSI C prototypes are supported in C++, K&R style function declarations will yield errors.

#GDBMNDBM_H_USES_PROTOTYPES

This symbol, if defined, indicates that gdbm/ndbm.h uses real ANSI C prototypes instead of K&R style function declarations without any parameter information. While ANSI C prototypes are supported in C++, K&R style function declarations will yield errors.

#GETGRENT_R_PROTO

This symbol encodes the prototype of getgrent_r. It is zero if d_getgrent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getgrent_r is defined.

#GETGRGID_R_PROTO

This symbol encodes the prototype of getgrgid_r. It is zero if d_getgrgid_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getgrgid_r is defined.

#GETGRNAM_R_PROTO

This symbol encodes the prototype of getgrnam_r. It is zero if d_getgrnam_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getgrnam_r is defined.

#GETHOSTBYADDR_R_PROTO

This symbol encodes the prototype of gethostbyaddr_r. It is zero if d_gethostbyaddr_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_gethostbyaddr_r is defined.

#GETHOSTBYNAME_R_PROTO

This symbol encodes the prototype of gethostbyname_r. It is zero if d_gethostbyname_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_gethostbyname_r is defined.

#GETHOSTENT_R_PROTO

This symbol encodes the prototype of gethostent_r. It is zero if d_gethostent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_gethostent_r is defined.

#GETLOGIN_R_PROTO

This symbol encodes the prototype of getlogin_r. It is zero if d_getlogin_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getlogin_r is defined.

#GETNETBYADDR_R_PROTO

This symbol encodes the prototype of getnetbyaddr_r. It is zero if d_getnetbyaddr_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getnetbyaddr_r is defined.

#GETNETBYNAME_R_PROTO

This symbol encodes the prototype of getnetbyname_r. It is zero if d_getnetbyname_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getnetbyname_r is defined.

#GETNETENT_R_PROTO

This symbol encodes the prototype of getnetent_r. It is zero if d_getnetent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getnetent_r is defined.

#GETPROTOBYNAME_R_PROTO

This symbol encodes the prototype of getprotobyname_r. It is zero if d_getprotobyname_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getprotobyname_r is defined.

#GETPROTOBYNUMBER_R_PROTO

This symbol encodes the prototype of getprotobynumber_r. It is zero if d_getprotobynumber_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getprotobynumber_r is defined.

#GETPROTOENT_R_PROTO

This symbol encodes the prototype of getprotoent_r. It is zero if d_getprotoent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getprotoent_r is defined.

#GETPWENT_R_PROTO

This symbol encodes the prototype of getpwent_r. It is zero if d_getpwent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getpwent_r is defined.

#GETPWNAM_R_PROTO

This symbol encodes the prototype of getpwnam_r. It is zero if d_getpwnam_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getpwnam_r is defined.

#GETPWUID_R_PROTO

This symbol encodes the prototype of getpwuid_r. It is zero if d_getpwuid_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getpwuid_r is defined.

#GETSERVBYNAME_R_PROTO

This symbol encodes the prototype of getservbyname_r. It is zero if d_getservbyname_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getservbyname_r is defined.

#GETSERVBYPORT_R_PROTO

This symbol encodes the prototype of getservbyport_r. It is zero if d_getservbyport_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getservbyport_r is defined.

#GETSERVENT_R_PROTO

This symbol encodes the prototype of getservent_r. It is zero if d_getservent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getservent_r is defined.

#GETSPNAM_R_PROTO

This symbol encodes the prototype of getspnam_r. It is zero if d_getspnam_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_getspnam_r is defined.

#HAS_DBMINIT_PROTO

This symbol, if defined, indicates that the system provides a prototype for the dbminit() function. Otherwise, it is up to the program to supply one. A good guess is

extern int dbminit(char *);

#HAS_DRAND48_PROTO

This symbol, if defined, indicates that the system provides a prototype for the drand48() function. Otherwise, it is up to the program to supply one. A good guess is

extern double drand48(void);

#HAS_FLOCK_PROTO

This symbol, if defined, indicates that the system provides a prototype for the flock() function. Otherwise, it is up to the program to supply one. A good guess is

extern int flock(int, int);

#HAS_GETHOST_PROTOS

This symbol, if defined, indicates that netdb.h includes prototypes for gethostent(), gethostbyname(), and gethostbyaddr(). Otherwise, it is up to the program to guess them. See netdbtype.U (part of metaconfig) for probing for various Netdb_xxx_t types.

#HAS_GETNET_PROTOS

This symbol, if defined, indicates that netdb.h includes prototypes for getnetent(), getnetbyname(), and getnetbyaddr(). Otherwise, it is up to the program to guess them. See netdbtype.U (part of metaconfig) for probing for various Netdb_xxx_t types.

#HAS_GETPROTO_PROTOS

This symbol, if defined, indicates that netdb.h includes prototypes for getprotoent(), getprotobyname(), and getprotobyaddr(). Otherwise, it is up to the program to guess them. See netdbtype.U (part of metaconfig) for probing for various Netdb_xxx_t types.

#HAS_GETSERV_PROTOS

This symbol, if defined, indicates that netdb.h includes prototypes for getservent(), getservbyname(), and getservbyaddr(). Otherwise, it is up to the program to guess them. See netdbtype.U (part of metaconfig) for probing for various Netdb_xxx_t types.

#HAS_MODFL_PROTO

This symbol, if defined, indicates that the system provides a prototype for the modfl() function. Otherwise, it is up to the program to supply one.

#HAS_SBRK_PROTO

This symbol, if defined, indicates that the system provides a prototype for the sbrk() function. Otherwise, it is up to the program to supply one. Good guesses are

extern void* sbrk(int);
extern void* sbrk(size_t);

#HAS_SETRESGID_PROTO

This symbol, if defined, indicates that the system provides a prototype for the setresgid() function. Otherwise, it is up to the program to supply one. Good guesses are

extern int setresgid(uid_t ruid, uid_t euid, uid_t suid);

#HAS_SETRESUID_PROTO

This symbol, if defined, indicates that the system provides a prototype for the setresuid() function. Otherwise, it is up to the program to supply one. Good guesses are

extern int setresuid(uid_t ruid, uid_t euid, uid_t suid);

#HAS_SHMAT_PROTOTYPE

This symbol, if defined, indicates that the sys/shm.h includes a prototype for shmat(). Otherwise, it is up to the program to guess one. Shmat_t shmat(int, Shmat_t, int) is a good guess, but not always right so it should be emitted by the program only when HAS_SHMAT_PROTOTYPE is not defined to avoid conflicting defs.

#HAS_SOCKATMARK_PROTO

This symbol, if defined, indicates that the system provides a prototype for the sockatmark() function. Otherwise, it is up to the program to supply one. A good guess is

extern int sockatmark(int);

#HAS_SYSCALL_PROTO

This symbol, if defined, indicates that the system provides a prototype for the syscall() function. Otherwise, it is up to the program to supply one. Good guesses are

extern int syscall(int,  ...);
extern int syscall(long, ...);

#HAS_TELLDIR_PROTO

This symbol, if defined, indicates that the system provides a prototype for the telldir() function. Otherwise, it is up to the program to supply one. A good guess is

extern long telldir(DIR*);

#NDBM_H_USES_PROTOTYPES

This symbol, if defined, indicates that ndbm.h uses real ANSI C prototypes instead of K&R style function declarations without any parameter information. While ANSI C prototypes are supported in C++, K&R style function declarations will yield errors.

#RANDOM_R_PROTO

This symbol encodes the prototype of random_r. It is zero if d_random_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_random_r is defined.

#READDIR_R_PROTO

This symbol encodes the prototype of readdir_r. It is zero if d_readdir_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_readdir_r is defined.

#SETGRENT_R_PROTO

This symbol encodes the prototype of setgrent_r. It is zero if d_setgrent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_setgrent_r is defined.

#SETHOSTENT_R_PROTO

This symbol encodes the prototype of sethostent_r. It is zero if d_sethostent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_sethostent_r is defined.

#SETLOCALE_R_PROTO

This symbol encodes the prototype of setlocale_r. It is zero if d_setlocale_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_setlocale_r is defined.

#SETNETENT_R_PROTO

This symbol encodes the prototype of setnetent_r. It is zero if d_setnetent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_setnetent_r is defined.

#SETPROTOENT_R_PROTO

This symbol encodes the prototype of setprotoent_r. It is zero if d_setprotoent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_setprotoent_r is defined.

#SETPWENT_R_PROTO

This symbol encodes the prototype of setpwent_r. It is zero if d_setpwent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_setpwent_r is defined.

#SETSERVENT_R_PROTO

This symbol encodes the prototype of setservent_r. It is zero if d_setservent_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_setservent_r is defined.

#SRANDOM_R_PROTO

This symbol encodes the prototype of srandom_r. It is zero if d_srandom_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_srandom_r is defined.

#SRAND48_R_PROTO

This symbol encodes the prototype of srand48_r. It is zero if d_srand48_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_srand48_r is defined.

#STRERROR_R_PROTO

This symbol encodes the prototype of strerror_r. It is zero if d_strerror_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_strerror_r is defined.

#TMPNAM_R_PROTO

This symbol encodes the prototype of tmpnam_r. It is zero if d_tmpnam_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_tmpnam_r is defined.

#TTYNAME_R_PROTO

This symbol encodes the prototype of ttyname_r. It is zero if d_ttyname_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_ttyname_r is defined.

#Reference-counted stack manipulation

Functions for pushing and pulling items on the stack when the stack is reference counted. They are intended as replacements for the old PUSHs, POPi, EXTEND etc pp macros within pp functions.

#rpp_context

NOTE: rpp_context is experimental and may change or be removed without notice.

Impose void, scalar or list context on the stack. First, pop extra items off the stack, then when gimme is: G_LIST: return as-is. G_VOID: pop everything back to mark G_SCALAR: move the top stack item (or &PL_sv_undef if none) to mark+1 and free everything above it.

void       rpp_context(      SV **mark, U8 gimme, SSize_t extra)
void  Perl_rpp_context(pTHX_ SV **mark, U8 gimme, SSize_t extra)

#rpp_extend

NOTE: rpp_extend is experimental and may change or be removed without notice.

Ensures that there is space on the stack to push n items, extending it if necessary.

void       rpp_extend(      SSize_t n)
void  Perl_rpp_extend(pTHX_ SSize_t n)

#rpp_invoke_xs

NOTE: rpp_invoke_xs is experimental and may change or be removed without notice.

Call the XS function associated with cv. Wraps the call if necessary to handle XS functions which are not aware of reference-counted stacks.

void       rpp_invoke_xs(      CV *cv)
void  Perl_rpp_invoke_xs(pTHX_ CV *cv)

#rpp_is_lone

NOTE: rpp_is_lone is experimental and may change or be removed without notice.

Indicates whether the stacked SV sv (assumed to be not yet popped off the stack) is only kept alive due to a single reference from the argument stack and/or and the temps stack.

This can used for example to decide whether the copying of return values in rvalue context can be skipped, or whether it shouldn't be assigned to in lvalue context.

bool       rpp_is_lone(      SV *sv)
bool  Perl_rpp_is_lone(pTHX_ SV *sv)

#rpp_pop_1_norc

NOTE: rpp_pop_1_norc is experimental and may change or be removed without notice.

Pop and return the top item off the argument stack and update PL_stack_sp. It's similar to rpp_popfree_1(), except that it actually returns a value, and it doesn't decrement the SV's reference count. On non-PERL_RC_STACK builds it actually increments the SV's reference count.

This is useful in cases where the popped value is immediately embedded somewhere e.g. via av_store(), allowing you skip decrementing and then immediately incrementing the reference count again (and risk prematurely freeing the SV if it had a RC of 1). On non-RC builds, the reference count bookkeeping still works too, which is why it should be used rather than a simple *PL_stack_sp--.

SV *       rpp_pop_1_norc()
SV *  Perl_rpp_pop_1_norc(pTHX)

#rpp_popfree_to

NOTE: rpp_popfree_to is experimental and may change or be removed without notice.

Pop and free all items on the argument stack above sp. On return, PL_stack_sp will be equal to sp.

void       rpp_popfree_to(      SV **sp)
void  Perl_rpp_popfree_to(pTHX_ SV **sp)

#rpp_popfree_to_NN

NOTE: rpp_popfree_to_NN is experimental and may change or be removed without notice.

A variant of rpp_popfree_to() which assumes that all the pointers being popped off the stack are non-NULL.

void       rpp_popfree_to_NN(      SV **sp)
void  Perl_rpp_popfree_to_NN(pTHX_ SV **sp)

#rpp_popfree_1

NOTE: rpp_popfree_1 is experimental and may change or be removed without notice.

Pop and free the top item on the argument stack and update PL_stack_sp.

void       rpp_popfree_1()
void  Perl_rpp_popfree_1(pTHX)

#rpp_popfree_1_NN

NOTE: rpp_popfree_1_NN is experimental and may change or be removed without notice.

A variant of rpp_popfree_1() which assumes that the pointer being popped off the stack is non-NULL.

void       rpp_popfree_1_NN()
void  Perl_rpp_popfree_1_NN(pTHX)

#rpp_popfree_2

NOTE: rpp_popfree_2 is experimental and may change or be removed without notice.

Pop and free the top two items on the argument stack and update PL_stack_sp.

void       rpp_popfree_2()
void  Perl_rpp_popfree_2(pTHX)

#rpp_popfree_2_NN

NOTE: rpp_popfree_2_NN is experimental and may change or be removed without notice.

A variant of rpp_popfree_2() which assumes that the two pointers being popped off the stack are non-NULL.

void       rpp_popfree_2_NN()
void  Perl_rpp_popfree_2_NN(pTHX)

#rpp_push_1

#rpp_push_IMM

#rpp_push_2

#rpp_xpush_1

#rpp_xpush_IMM

#rpp_xpush_2

NOTE: all these forms are experimental and may change or be removed without notice.

Push one or two SVs onto the stack, incrementing their reference counts and updating PL_stack_sp. With the x variants, it extends the stack first. The IMM variants assume that the single argument is an immortal such as <&PL_sv_undef> and, for efficiency, will skip incrementing its reference count.

void       rpp_push_1   (      SV *sv)
void  Perl_rpp_push_1   (pTHX_ SV *sv)
void       rpp_push_IMM (      SV *sv)
void  Perl_rpp_push_IMM (pTHX_ SV *sv)
void       rpp_push_2   (      SV *sv1, SV *sv2)
void  Perl_rpp_push_2   (pTHX_ SV *sv1, SV *sv2)
void       rpp_xpush_1  (      SV *sv)
void  Perl_rpp_xpush_1  (pTHX_ SV *sv)
void       rpp_xpush_IMM(      SV *sv)
void  Perl_rpp_xpush_IMM(pTHX_ SV *sv)
void       rpp_xpush_2  (      SV *sv1, SV *sv2)
void  Perl_rpp_xpush_2  (pTHX_ SV *sv1, SV *sv2)

#rpp_push_1_norc

NOTE: rpp_push_1_norc is experimental and may change or be removed without notice.

Push sv onto the stack without incrementing its reference count, and update PL_stack_sp. On non-PERL_RC_STACK builds, mortalise too.

This is most useful where an SV has just been created and already has a reference count of 1, but has not yet been anchored anywhere.

void       rpp_push_1_norc(      SV *sv)
void  Perl_rpp_push_1_norc(pTHX_ SV *sv)

#rpp_push_2*

Described under "rpp_push_1"

#rpp_replace_at

NOTE: rpp_replace_at is experimental and may change or be removed without notice.

Replace the SV at address sp within the stack with sv, while suitably adjusting reference counts. Equivalent to *sp = sv, except with proper reference count handling.

void       rpp_replace_at(      SV **sp, SV *sv)
void  Perl_rpp_replace_at(pTHX_ SV **sp, SV *sv)

#rpp_replace_at_NN

NOTE: rpp_replace_at_NN is experimental and may change or be removed without notice.

A variant of rpp_replace_at() which assumes that the SV pointer on the stack is non-NULL.

void       rpp_replace_at_NN(      SV **sp, SV *sv)
void  Perl_rpp_replace_at_NN(pTHX_ SV **sp, SV *sv)

#rpp_replace_at_norc

NOTE: rpp_replace_at_norc is experimental and may change or be removed without notice.

Replace the SV at address sp within the stack with sv, while suitably adjusting the reference count of the old SV. Equivalent to *sp = sv, except with proper reference count handling.

sv's reference count doesn't get incremented. On non-PERL_RC_STACK builds, it gets mortalised too.

This is most useful where an SV has just been created and already has a reference count of 1, but has not yet been anchored anywhere.

void       rpp_replace_at_norc(      SV **sp, SV *sv)
void  Perl_rpp_replace_at_norc(pTHX_ SV **sp, SV *sv)

#rpp_replace_at_norc_NN

NOTE: rpp_replace_at_norc_NN is experimental and may change or be removed without notice.

A variant of rpp_replace_at_norc() which assumes that the SV pointer on the stack is non-NULL.

void       rpp_replace_at_norc_NN(      SV **sp, SV *sv)
void  Perl_rpp_replace_at_norc_NN(pTHX_ SV **sp, SV *sv)

#rpp_replace_1_1

#rpp_replace_1_1_NN

#rpp_replace_1_IMM_NN

NOTE: all these forms are experimental and may change or be removed without notice.

Replace the current top stack item with sv, while suitably adjusting reference counts. Equivalent to rpp_popfree_1(); rpp_push_1(sv), but is more efficient and handles both SVs being the same.

The _NN variant assumes that the pointer on the stack to the SV being freed is non-NULL.

The IMM_NN variant is like the _NN variant, but in addition, assumes that the single argument is an immortal such as <&PL_sv_undef> and, for efficiency, will skip incrementing its reference count.

void       rpp_replace_1_1     (      SV *sv)
void  Perl_rpp_replace_1_1     (pTHX_ SV *sv)
void       rpp_replace_1_1_NN  (      SV *sv)
void  Perl_rpp_replace_1_1_NN  (pTHX_ SV *sv)
void       rpp_replace_1_IMM_NN(      SV *sv)
void  Perl_rpp_replace_1_IMM_NN(pTHX_ SV *sv)

#rpp_replace_2_1

#rpp_replace_2_1_NN

#rpp_replace_2_IMM_NN

NOTE: all these forms are experimental and may change or be removed without notice.

Replace the current top to stacks item with sv, while suitably adjusting reference counts. Equivalent to rpp_popfree_2(); rpp_push_1(sv), but is more efficient and handles SVs being the same.

The _NN variant assumes that the pointers on the stack to the SVs being freed are non-NULL.

The IMM_NN variant is like the _NN variant, but in addition, assumes that the single argument is an immortal such as <&PL_sv_undef> and, for efficiency, will skip incrementing its reference count.

void       rpp_replace_2_1     (      SV *sv)
void  Perl_rpp_replace_2_1     (pTHX_ SV *sv)
void       rpp_replace_2_1_NN  (      SV *sv)
void  Perl_rpp_replace_2_1_NN  (pTHX_ SV *sv)
void       rpp_replace_2_IMM_NN(      SV *sv)
void  Perl_rpp_replace_2_IMM_NN(pTHX_ SV *sv)

#rpp_stack_is_rc

NOTE: rpp_stack_is_rc is experimental and may change or be removed without notice.

Returns a boolean value indicating whether the stack is currently reference-counted. Note that if the stack is split (bottom half RC, top half non-RC), this function returns false, even if the top half currently contains zero items.

bool       rpp_stack_is_rc()
bool  Perl_rpp_stack_is_rc(pTHX)

#rpp_try_AMAGIC_1

#rpp_try_AMAGIC_2

NOTE: both forms are experimental and may change or be removed without notice.

Check whether either of the one or two SVs at the top of the stack is magical or a ref, and in either case handle it specially: invoke get magic, call an overload method, or replace a ref with a temporary numeric value, as appropriate. If this function returns true, it indicates that the correct return value is already on the stack. Intended to be used at the beginning of the PP function for unary or binary ops.

bool       rpp_try_AMAGIC_1(      int method, int flags)
bool  Perl_rpp_try_AMAGIC_1(pTHX_ int method, int flags)
bool       rpp_try_AMAGIC_2(      int method, int flags)
bool  Perl_rpp_try_AMAGIC_2(pTHX_ int method, int flags)

#rpp_xpush_IMM*

#rpp_xpush_1*

#rpp_xpush_2*

Described under "rpp_push_1"

#XSPP_wrapped

NOTE: XSPP_wrapped is experimental and may change or be removed without notice.

Declare and wrap a non-reference-counted PP-style function. On traditional perl builds where the stack isn't reference-counted, this just produces a function declaration like

OP * xsppw_name(pTHX)

Conversely, in ref-counted builds it creates xsppw_name() as a small wrapper function which calls the real function via a wrapper which processes the args and return values to ensure that reference counts are properly handled for code which uses old-style dSP, PUSHs(), POPs() etc, which don't adjust the reference counts of the items they manipulate.

xsppw_nargs indicates how many arguments the function consumes off the stack. It can be a constant value or an expression, such as

((PL_op->op_flags & OPf_STACKED) ? 2 : 1)

Alternatively if xsppw_nlists is 1, it indicates that the PP function consumes a list (or - rarely - if 2, consumes two lists, like pp_aassign()), as indicated by the top markstack position.

This is intended as a temporary fix when converting XS code to run under PERL_RC_STACK builds. In the longer term, the PP function should be rewritten to replace PUSHs() etc with rpp_push_1() etc.

XSPP_wrapped(xsppw_name, I32 xsppw_nargs, I32 xsppw_nlists)

#REGEXP Functions

#pregcomp

#pregexec

Described in perlreguts.

REGEXP *       pregcomp(      SV * const pattern,
                              const U32 flags)
REGEXP *  Perl_pregcomp(pTHX_ SV * const pattern,
                              const U32 flags)
I32            pregexec(      REGEXP * const prog,
                              char *stringarg, char *strend,
                              char *strbeg, SSize_t minend,
                              SV *screamer, U32 nosave)
I32       Perl_pregexec(pTHX_ REGEXP * const prog,
                              char *stringarg, char *strend,
                              char *strbeg, SSize_t minend,
                              SV *screamer, U32 nosave)

#re_compile

Compile the regular expression pattern pattern, returning a pointer to the compiled object for later matching with the internal regex engine.

This function is typically used by a custom regexp engine .comp() function to hand off to the core regexp engine those patterns it doesn't want to handle itself (typically passing through the same flags it was called with). In almost all other cases, a regexp should be compiled by calling "pregcomp" to compile using the currently active regexp engine.

If pattern is already a REGEXP, this function does nothing but return a pointer to the input. Otherwise the PV is extracted and treated like a string representing a pattern. See perlre.

The possible flags for rx_flags are documented in perlreapi. Their names all begin with RXf_.

REGEXP *       re_compile(      SV * const pattern,
                                U32 orig_rx_flags)
REGEXP *  Perl_re_compile(pTHX_ SV * const pattern,
                                U32 orig_rx_flags)

#re_dup_guts

Duplicate a regexp.

This routine is expected to clone a given regexp structure. It is only compiled under USE_ITHREADS.

After all of the core data stored in struct regexp is duplicated the regexp_engine.dupe method is used to copy any private data stored in the *pprivate pointer. This allows extensions to handle any duplication they need to do.

void       re_dup_guts(      const REGEXP *sstr, REGEXP *dstr,
                             CLONE_PARAMS *param)
void  Perl_re_dup_guts(pTHX_ const REGEXP *sstr, REGEXP *dstr,
                             CLONE_PARAMS *param)

#REGEX_LOCALE_CHARSET

#REGEXP

Described in perlreapi.

#regexp

The regexp/REGEXP struct, see perlreapi for further documentation on the individual fields. The struct is ordered so that the most commonly used fields are placed at the start.

Any patch that adds items to this struct will need to include changes to sv.c (Perl_re_dup()) and regcomp.c (pregfree()). This involves freeing or cloning items in the regexp's data array based on the data item's type.

#regexp_engine

When a regexp is compiled, its engine field is then set to point at the appropriate structure, so that when it needs to be used Perl can find the right routines to do so.

In order to install a new regexp handler, $^H{regcomp} is set to an integer which (when casted appropriately) resolves to one of these structures. When compiling, the comp method is executed, and the resulting regexp structure's engine field is expected to point back at the same structure.

The pTHX_ symbol in the definition is a macro used by Perl under threading to provide an extra argument to the routine holding a pointer back to the interpreter that is executing the regexp. So under threading all routines get an extra argument.

#regexp_paren_pair

Described in perlreapi.

#regmatch_info

Some basic information about the current match that is created by Perl_regexec_flags and then passed to regtry(), regmatch() etc. It is allocated as a local var on the stack, so nothing should be stored in it that needs preserving or clearing up on croak(). For that, see the aux_info and aux_info_eval members of the regmatch_state union.

#REXEC_COPY_SKIP_POST

#REXEC_COPY_SKIP_PRE

#REXEC_COPY_STR

#RX_BUFF_IDX_CARET_FULLMATCH

#RX_BUFF_IDX_CARET_POSTMATCH

#RX_BUFF_IDX_CARET_PREMATCH

#RX_BUFF_IDX_FULLMATCH

#RX_BUFF_IDX_POSTMATCH

#RX_BUFF_IDX_PREMATCH

#RX_MATCH_COPIED

#RXapif_ALL

#RXapif_CLEAR

#RXapif_DELETE

#RXapif_EXISTS

#RXapif_FETCH

#RXapif_FIRSTKEY

#RXapif_NEXTKEY

#RXapif_ONE

#RXapif_REGNAME

#RXapif_REGNAMES

#RXapif_REGNAMES_COUNT

#RXapif_SCALAR

#RXapif_STORE

#RXf_NO_INPLACE_SUBST

#RXf_NULL

#RXf_SKIPWHITE

#RXf_SPLIT

#RXf_START_ONLY

#RXf_WHITE

#RXf_PMf_EXTENDED

#RXf_PMf_FOLD

#RXf_PMf_KEEPCOPY

#RXf_PMf_MULTILINE

#RXf_PMf_SINGLELINE

#RXf_SKIPWHITE*

#RXf_SPLIT*

#RXf_START_ONLY*

#RXf_WHITE*

#struct regexp

#SV_SAVED_COPY

Described in perlreapi.

RX_MATCH_COPIED(const REGEXP * rx_sv)

#SvRX

Convenience macro to get the REGEXP from a SV. This is approximately equivalent to the following snippet:

if (SvMAGICAL(sv))
    mg_get(sv);
if (SvROK(sv))
    sv = MUTABLE_SV(SvRV(sv));
if (SvTYPE(sv) == SVt_REGEXP)
    return (REGEXP*) sv;

NULL will be returned if a REGEXP* is not found.

REGEXP *  SvRX(SV *sv)

#SvRXOK

Returns a boolean indicating whether the SV (or the one it references) is a REGEXP.

If you want to do something with the REGEXP* later use SvRX instead and check for NULL.

bool  SvRXOK(SV* sv)

#Reports and Formats

These are used in the simple report generation feature of Perl. See perlform.

#IoBOTTOM_GV

#IoBOTTOM_NAME

#IoFMT_GV

#IoFMT_NAME

#IoLINES

#IoLINES_LEFT

#IoPAGE

#IoPAGE_LEN

#IoTOP_GV

#IoTOP_NAME

Described in perlguts.

GV *    IoBOTTOM_GV  (IO *io)
char *  IoBOTTOM_NAME(IO *io)
GV *    IoFMT_GV     (IO *io)
char *  IoFMT_NAME   (IO *io)
IV      IoLINES      (IO *io)
IV      IoLINES_LEFT (IO *io)
IV      IoPAGE       (IO *io)
IV      IoPAGE_LEN   (IO *io)
GV *    IoTOP_GV     (IO *io)
char *  IoTOP_NAME   (IO *io)

#Signals

#HAS_SIGINFO_SI_ADDR

This symbol, if defined, indicates that siginfo_t has the si_addr member

#HAS_SIGINFO_SI_BAND

This symbol, if defined, indicates that siginfo_t has the si_band member

#HAS_SIGINFO_SI_ERRNO

This symbol, if defined, indicates that siginfo_t has the si_errno member

#HAS_SIGINFO_SI_PID

This symbol, if defined, indicates that siginfo_t has the si_pid member

#HAS_SIGINFO_SI_STATUS

This symbol, if defined, indicates that siginfo_t has the si_status member

#HAS_SIGINFO_SI_UID

This symbol, if defined, indicates that siginfo_t has the si_uid member

#HAS_SIGINFO_SI_VALUE

This symbol, if defined, indicates that siginfo_t has the si_value member

#PERL_SIGNALS_UNSAFE_FLAG

If this bit in PL_signals is set, the system is uing the pre-Perl 5.8 unsafe signals. See "PERL_SIGNALS" in perlrun and "Deferred Signals (Safe Signals)" in perlipc.

U32  PERL_SIGNALS_UNSAFE_FLAG

#rsignal

A wrapper for the C library functions sigaction(2) or signal(2). Use this instead of those libc functions, as the Perl version gives the safest available implementation, and knows things that interact with the rest of the perl interpreter.

Sighandler_t       rsignal(      int i, Sighandler_t t)
Sighandler_t  Perl_rsignal(pTHX_ int i, Sighandler_t t)

#rsignal_state

Returns a the current signal handler for signal signo. See "rsignal".

Sighandler_t       rsignal_state(      int i)
Sighandler_t  Perl_rsignal_state(pTHX_ int i)

#SIG_NAME

This symbol contains a list of signal names in order of signal number. This is intended to be used as a static array initialization, like this:

char *sig_name[] = { SIG_NAME };

The signals in the list are separated with commas, and each signal is surrounded by double quotes. There is no leading SIG in the signal name, i.e. SIGQUIT is known as "QUIT". Gaps in the signal numbers (up to NSIG) are filled in with NUMnn, etc., where nn is the actual signal number (e.g. NUM37). The signal number for sig_name[i] is stored in sig_num[i]. The last element is 0 to terminate the list with a NULL. This corresponds to the 0 at the end of the sig_name_init list. Note that this variable is initialized from the sig_name_init, not from sig_name (which is unused).

#SIG_NUM

This symbol contains a list of signal numbers, in the same order as the SIG_NAME list. It is suitable for static array initialization, as in:

int sig_num[] = { SIG_NUM };

The signals in the list are separated with commas, and the indices within that list and the SIG_NAME list match, so it's easy to compute the signal name from a number or vice versa at the price of a small dynamic linear lookup. Duplicates are allowed, but are moved to the end of the list. The signal number corresponding to sig_name[i] is sig_number[i]. if (i < NSIG) then sig_number[i] == i. The last element is 0, corresponding to the 0 at the end of the sig_name_init list. Note that this variable is initialized from the sig_num_init, not from sig_num (which is unused).

#SIG_SIZE

This variable contains the number of elements of the SIG_NAME and SIG_NUM arrays, excluding the final NULL entry.

#Sigjmp_buf

This is the buffer type to be used with Sigsetjmp and Siglongjmp.

#Siglongjmp

This macro is used in the same way as siglongjmp(), but will invoke traditional longjmp() if siglongjmp isn't available. See "HAS_SIGSETJMP".

void  Siglongjmp(jmp_buf env, int val)

#Sigsetjmp

This macro is used in the same way as sigsetjmp(), but will invoke traditional setjmp() if sigsetjmp isn't available. See "HAS_SIGSETJMP".

int  Sigsetjmp(jmp_buf env, int savesigs)

#whichsig

#whichsig_pv

#whichsig_pvn

#whichsig_sv

These all convert a signal name into its corresponding signal number; returning -1 if no corresponding number was found.

They differ only in the source of the signal name:

whichsig_pv takes the name from the NUL-terminated string starting at sig.

whichsig is merely a different spelling, a synonym, of whichsig_pv.

whichsig_pvn takes the name from the string starting at sig, with length len bytes.

whichsig_sv takes the name from the PV stored in the SV sigsv.

I32       whichsig    (      const char *sig)
I32       whichsig_pv (      const char *sig)
I32  Perl_whichsig_pv (pTHX_ const char *sig)
I32       whichsig_pvn(      const char *sig, STRLEN len)
I32  Perl_whichsig_pvn(pTHX_ const char *sig, STRLEN len)
I32       whichsig_sv (      SV *sigsv)
I32  Perl_whichsig_sv (pTHX_ SV *sigsv)

#Site configuration

These variables give details as to where various libraries, installation destinations, etc., go, as well as what various installation options were selected

#ARCHLIB

This variable, if defined, holds the name of the directory in which the user wants to put architecture-dependent public library files for perl5. It is most often a local directory such as /usr/local/lib. Programs using this variable must be prepared to deal with filename expansion. If ARCHLIB is the same as PRIVLIB, it is not defined, since presumably the program already searches PRIVLIB.

#ARCHLIB_EXP

This symbol contains the ~name expanded version of ARCHLIB, to be used in programs that are not prepared to deal with ~ expansion at run-time.

#ARCHNAME

This symbol holds a string representing the architecture name. It may be used to construct an architecture-dependant pathname where library files may be held under a private library, for instance.

#BIN

This symbol holds the path of the bin directory where the package will be installed. Program must be prepared to deal with ~name substitution.

#BIN_EXP

This symbol is the filename expanded version of the BIN symbol, for programs that do not want to deal with that at run-time.

#INSTALL_USR_BIN_PERL

This symbol, if defined, indicates that Perl is to be installed also as /usr/bin/perl.

#MULTIARCH

This symbol, if defined, signifies that the build process will produce some binary files that are going to be used in a cross-platform environment. This is the case for example with the NeXT "fat" binaries that contain executables for several CPUs.

#PERL_INC_VERSION_LIST

This variable specifies the list of subdirectories in over which perl.c:incpush() and lib/lib.pm will automatically search when adding directories to @INC, in a format suitable for a C initialization string. See the inc_version_list entry in Porting/Glossary for more details.

#PERL_OTHERLIBDIRS

This variable contains a colon-separated set of paths for the perl binary to search for additional library files or modules. These directories will be tacked to the end of @INC. Perl will automatically search below each path for version- and architecture-specific directories. See "PERL_INC_VERSION_LIST" for more details.

#PERL_RELOCATABLE_INC

This symbol, if defined, indicates that we'd like to relocate entries in @INC at run time based on the location of the perl binary.

#PERL_TARGETARCH

This symbol, if defined, indicates the target architecture Perl has been cross-compiled to. Undefined if not a cross-compile.

#PERL_USE_DEVEL

This symbol, if defined, indicates that Perl was configured with -Dusedevel, to enable development features. This should not be done for production builds.

#PERL_VENDORARCH

If defined, this symbol contains the name of a private library. The library is private in the sense that it needn't be in anyone's execution path, but it should be accessible by the world. It may have a ~ on the front. The standard distribution will put nothing in this directory. Vendors who distribute perl may wish to place their own architecture-dependent modules and extensions in this directory with

MakeMaker Makefile.PL INSTALLDIRS=vendor

or equivalent. See INSTALL for details.

#PERL_VENDORARCH_EXP

This symbol contains the ~name expanded version of PERL_VENDORARCH, to be used in programs that are not prepared to deal with ~ expansion at run-time.

#PERL_VENDORLIB_EXP

This symbol contains the ~name expanded version of VENDORLIB, to be used in programs that are not prepared to deal with ~ expansion at run-time.

#PERL_VENDORLIB_STEM

This define is PERL_VENDORLIB_EXP with any trailing version-specific component removed. The elements in inc_version_list (inc_version_list.U (part of metaconfig)) can be tacked onto this variable to generate a list of directories to search.

#PRIVLIB

This symbol contains the name of the private library for this package. The library is private in the sense that it needn't be in anyone's execution path, but it should be accessible by the world. The program should be prepared to do ~ expansion.

#PRIVLIB_EXP

This symbol contains the ~name expanded version of PRIVLIB, to be used in programs that are not prepared to deal with ~ expansion at run-time.

#SITEARCH

This symbol contains the name of the private library for this package. The library is private in the sense that it needn't be in anyone's execution path, but it should be accessible by the world. The program should be prepared to do ~ expansion. The standard distribution will put nothing in this directory. After perl has been installed, users may install their own local architecture-dependent modules in this directory with

MakeMaker Makefile.PL

or equivalent. See INSTALL for details.

#SITEARCH_EXP

This symbol contains the ~name expanded version of SITEARCH, to be used in programs that are not prepared to deal with ~ expansion at run-time.

#SITELIB

This symbol contains the name of the private library for this package. The library is private in the sense that it needn't be in anyone's execution path, but it should be accessible by the world. The program should be prepared to do ~ expansion. The standard distribution will put nothing in this directory. After perl has been installed, users may install their own local architecture-independent modules in this directory with

MakeMaker Makefile.PL

or equivalent. See INSTALL for details.

#SITELIB_EXP

This symbol contains the ~name expanded version of SITELIB, to be used in programs that are not prepared to deal with ~ expansion at run-time.

#SITELIB_STEM

This define is SITELIB_EXP with any trailing version-specific component removed. The elements in inc_version_list (inc_version_list.U (part of metaconfig)) can be tacked onto this variable to generate a list of directories to search.

#STARTPERL

This variable contains the string to put in front of a perl script to make sure (one hopes) that it runs with perl and not some shell.

#USE_BSD_GETPGRP

This symbol, if defined, indicates that getpgrp needs one arguments whereas USG one needs none.

#USE_BSD_SETPGRP

This symbol, if defined, indicates that setpgrp needs two arguments whereas USG one needs none. See also "HAS_SETPGID" for a POSIX interface.

#USE_C_BACKTRACE

This symbol, if defined, indicates that Perl should be built with support for backtrace.

#USE_CPLUSPLUS

This symbol, if defined, indicates that a C++ compiler was used to compiled Perl and will be used to compile extensions.

#USE_CROSS_COMPILE

This symbol, if defined, indicates that Perl is being cross-compiled.

#USE_DTRACE

This symbol, if defined, indicates that Perl should be built with support for DTrace.

#USE_DYNAMIC_LOADING

This symbol, if defined, indicates that dynamic loading of some sort is available.

#USE_FAST_STDIO

This symbol, if defined, indicates that Perl should be built to use 'fast stdio'. Defaults to define in Perls 5.8 and earlier, to undef later.

#USE_ITHREADS

This symbol, if defined, indicates that Perl should be built to use the interpreter-based threading implementation.

#USE_KERN_PROC_PATHNAME

This symbol, if defined, indicates that we can use sysctl with KERN_PROC_PATHNAME to get a full path for the executable, and hence convert $^X to an absolute path.

#USE_LARGE_FILES

This symbol, if defined, indicates that large file support should be used when available.

#USE_LONG_DOUBLE

This symbol, if defined, indicates that long doubles should be used when available.

#USE_MORE_BITS

This symbol, if defined, indicates that 64-bit interfaces and long doubles should be used when available.

#USE_NSGETEXECUTABLEPATH

This symbol, if defined, indicates that we can use _NSGetExecutablePath and realpath to get a full path for the executable, and hence convert $^X to an absolute path.

#USE_PERLIO

This symbol, if defined, indicates that the PerlIO abstraction should be used throughout. If not defined, stdio should be used in a fully backward compatible manner.

#USE_QUADMATH

This symbol, if defined, indicates that the quadmath library should be used when available.

#USE_REENTRANT_API

This symbol, if defined, indicates that Perl should try to use the various _r versions of library functions. This is extremely experimental.

#USE_SEMCTL_SEMID_DS

This symbol, if defined, indicates that struct semid_ds * is used for semctl IPC_STAT.

#USE_SEMCTL_SEMUN

This symbol, if defined, indicates that union semun is used for semctl IPC_STAT.

#USE_SITECUSTOMIZE

This symbol, if defined, indicates that sitecustomize should be used.

#USE_SOCKS

This symbol, if defined, indicates that Perl should be built to use socks.

#USE_STAT_BLOCKS

This symbol is defined if this system has a stat structure declaring st_blksize and st_blocks.

#USE_STDIO_BASE

This symbol is defined if the _base field (or similar) of the stdio FILE structure can be used to access the stdio buffer for a file handle. If this is defined, then the FILE_base(fp) macro will also be defined and should be used to access this field. Also, the FILE_bufsiz(fp) macro will be defined and should be used to determine the number of bytes in the buffer. USE_STDIO_BASE will never be defined unless USE_STDIO_PTR is.

#USE_STDIO_PTR

This symbol is defined if the _ptr and _cnt fields (or similar) of the stdio FILE structure can be used to access the stdio buffer for a file handle. If this is defined, then the FILE_ptr(fp) and FILE_cnt(fp) macros will also be defined and should be used to access these fields.

#USE_STRICT_BY_DEFAULT

This symbol, if defined, enables additional defaults. At this time it only enables implicit strict by default.

#USE_THREADS

This symbol, if defined, indicates that Perl should be built to use threads. At present, it is a synonym for and USE_ITHREADS, but eventually the source ought to be changed to use this to mean _any_ threading implementation.

#USE_64_BIT_ALL

This symbol, if defined, indicates that 64-bit integers should be used when available. If not defined, the native integers will be used (be they 32 or 64 bits). The maximal possible 64-bitness is employed: LP64 or ILP64, meaning that you will be able to use more than 2 gigabytes of memory. This mode is even more binary incompatible than USE_64_BIT_INT. You may not be able to run the resulting executable in a 32-bit CPU at all or you may need at least to reboot your OS to 64-bit mode.

#USE_64_BIT_INT

This symbol, if defined, indicates that 64-bit integers should be used when available. If not defined, the native integers will be employed (be they 32 or 64 bits). The minimal possible 64-bitness is used, just enough to get 64-bit integers into Perl. This may mean using for example "long longs", while your memory may still be limited to 2 gigabytes.

#Sockets configuration values

#HAS_SOCKADDR_IN6

This symbol, if defined, indicates the availability of struct sockaddr_in6;

#HAS_SOCKADDR_SA_LEN

This symbol, if defined, indicates that the struct sockaddr structure has a member called sa_len, indicating the length of the structure.

#HAS_SOCKADDR_STORAGE

This symbol, if defined, indicates the availability of struct sockaddr_storage;

#HAS_SOCKATMARK

This symbol, if defined, indicates that the sockatmark routine is available to test whether a socket is at the out-of-band mark.

#HAS_SOCKET

This symbol, if defined, indicates that the BSD socket interface is supported.

#HAS_SOCKETPAIR

This symbol, if defined, indicates that the BSD socketpair() call is supported.

#HAS_SOCKS5_INIT

This symbol, if defined, indicates that the socks5_init routine is available to initialize SOCKS 5.

#I_SOCKS

This symbol, if defined, indicates that socks.h exists and should be included.

#ifdef I_SOCKS
    #include <socks.h>
#endif

#I_SYS_SOCKIO

This symbol, if defined, indicates the sys/sockio.h should be included to get socket ioctl options, like SIOCATMARK.

#ifdef I_SYS_SOCKIO
    #include <sys_sockio.h>
#endif

#Source Filters

#apply_builtin_cv_attributes

Given an OP_LIST containing attribute definitions, filter it for known builtin attributes to apply to the cv, returning a possibly-smaller list containing just the remaining ones.

OP *       apply_builtin_cv_attributes(      CV *cv,
                                             OP *attrlist)
OP *  Perl_apply_builtin_cv_attributes(pTHX_ CV *cv,
                                             OP *attrlist)

#filter_add

Described in perlfilter.

SV *       filter_add(      filter_t funcp, SV *datasv)
SV *  Perl_filter_add(pTHX_ filter_t funcp, SV *datasv)

#filter_del

Delete most recently added instance of the filter function argument

void       filter_del(      filter_t funcp)
void  Perl_filter_del(pTHX_ filter_t funcp)

#filter_read

Described in perlfilter.

I32       filter_read(      int idx, SV *buf_sv, int maxlen)
I32  Perl_filter_read(pTHX_ int idx, SV *buf_sv, int maxlen)

#scan_vstring

Returns a pointer to the next character after the parsed vstring, as well as updating the passed in sv.

Function must be called like

sv = sv_2mortal(newSV(5));
s = scan_vstring(s,e,sv);

where s and e are the start and end of the string. The sv should already be large enough to store the vstring passed in, for performance reasons.

This function may croak if fatal warnings are enabled in the calling scope, hence the sv_2mortal in the example (to prevent a leak). Make sure to do SvREFCNT_inc afterwards if you use sv_2mortal.

char *       scan_vstring(      const char *s,
                                const char * const e, SV *sv)
char *  Perl_scan_vstring(pTHX_ const char *s,
                                const char * const e, SV *sv)

#start_subparse

Set things up for parsing a subroutine.

If is_format is non-zero, the input is to be considered a format sub (a specialised sub used to implement perl's format feature); else a normal sub.

flags are added to the flags for PL_compcv. flags may include the CVf_IsMETHOD bit, which causes the new subroutine to be a method.

This returns the value of PL_savestack_ix that was in effect upon entry to the function;

I32       start_subparse(      I32 is_format, U32 flags)
I32  Perl_start_subparse(pTHX_ I32 is_format, U32 flags)

#Stack Manipulation Macros

#dMARK

Declare a stack marker variable, mark, for the XSUB. See "MARK" and "dORIGMARK".

dMARK;

#dORIGMARK

Saves the original stack mark for the XSUB. See "ORIGMARK".

dORIGMARK;

#dSP

Declares a local copy of perl's stack pointer for the XSUB, available via the SP macro. See "SP".

dSP;

#dTARGET

Declare that this function uses TARG, and initializes it

dTARGET;

#EXTEND

Used to extend the argument stack for an XSUB's return values. Once used, guarantees that there is room for at least nitems to be pushed onto the stack.

void  EXTEND(SP, SSize_t nitems)

#MARK

Stack marker variable for the XSUB. See "dMARK".

#mPUSHi

Push an integer onto the stack. The stack must have room for this element. Does not use TARG. See also "PUSHi", "mXPUSHi" and "XPUSHi".

void  mPUSHi(IV iv)

#mPUSHn

Push a double onto the stack. The stack must have room for this element. Does not use TARG. See also "PUSHn", "mXPUSHn" and "XPUSHn".

void  mPUSHn(NV nv)

#mPUSHp

Push a string onto the stack. The stack must have room for this element. The len indicates the length of the string. Does not use TARG. See also "PUSHp", "mXPUSHp" and "XPUSHp".

void  mPUSHp(char* str, STRLEN len)

#mPUSHpvs

A variation on mPUSHp that takes a literal string and calculates its size directly.

void  mPUSHpvs("literal string")

#mPUSHs

Push an SV onto the stack and mortalizes the SV. The stack must have room for this element. Does not use TARG. See also "PUSHs" and "mXPUSHs".

void  mPUSHs(SV* sv)

#mPUSHu

Push an unsigned integer onto the stack. The stack must have room for this element. Does not use TARG. See also "PUSHu", "mXPUSHu" and "XPUSHu".

void  mPUSHu(UV uv)

#mXPUSHi

Push an integer onto the stack, extending the stack if necessary. Does not use TARG. See also "XPUSHi", "mPUSHi" and "PUSHi".

void  mXPUSHi(IV iv)

#mXPUSHn

Push a double onto the stack, extending the stack if necessary. Does not use TARG. See also "XPUSHn", "mPUSHn" and "PUSHn".

void  mXPUSHn(NV nv)

#mXPUSHp

Push a string onto the stack, extending the stack if necessary. The len indicates the length of the string. Does not use TARG. See also "XPUSHp", mPUSHp and PUSHp.

void  mXPUSHp(char* str, STRLEN len)

#mXPUSHpvs

A variation on mXPUSHp that takes a literal string and calculates its size directly.

void  mXPUSHpvs("literal string")

#mXPUSHs

Push an SV onto the stack, extending the stack if necessary and mortalizes the SV. Does not use TARG. See also "XPUSHs" and "mPUSHs".

void  mXPUSHs(SV* sv)

#mXPUSHu

Push an unsigned integer onto the stack, extending the stack if necessary. Does not use TARG. See also "XPUSHu", "mPUSHu" and "PUSHu".

void  mXPUSHu(UV uv)

#newXSproto

Used by xsubpp to hook up XSUBs as Perl subs. Adds Perl prototypes to the subs.

#ORIGMARK

The original stack mark for the XSUB. See "dORIGMARK".

#PL_markstack

#PL_markstack_ptr

#PL_savestack

#PL_savestack_ix

#PL_scopestack

#PL_scopestack_ix

#PL_scopestack_name

#PL_stack_base

#PL_stack_sp

#PL_tmps_floor

#PL_tmps_ix

#PL_tmps_stack

Described in perlguts.

#POPi

Pops an integer off the stack.

IV  POPi

#POPl

Pops a long off the stack.

long  POPl

#POPn

Pops a double off the stack.

NV  POPn

#POPp

#POPpx

These each pop a string off the stack. There are two names for historical reasons.

char*  POPp
char*  POPpx

#POPpbytex

Pops a string off the stack which must consist of bytes i.e. characters < 256.

char*  POPpbytex

#POPpx*

Described under "POPp"

#POPs

Pops an SV off the stack.

SV*  POPs

#POPu

Pops an unsigned integer off the stack.

UV  POPu

#POPul

Pops an unsigned long off the stack.

long  POPul

#PUSHi

Push an integer onto the stack. The stack must have room for this element. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mPUSHi" instead. See also "XPUSHi" and "mXPUSHi".

void  PUSHi(IV iv)

#PUSHMARK

Opening bracket for arguments on a callback. See "PUTBACK" and perlcall.

void  PUSHMARK(SP)

#PUSHmortal

Push a new mortal SV onto the stack. The stack must have room for this element. Does not use TARG. See also "PUSHs", "XPUSHmortal" and "XPUSHs".

void  PUSHmortal

#PUSHn

Push a double onto the stack. The stack must have room for this element. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mPUSHn" instead. See also "XPUSHn" and "mXPUSHn".

void  PUSHn(NV nv)

#PUSHp

Push a string onto the stack. The stack must have room for this element. The len indicates the length of the string. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mPUSHp" instead. See also "XPUSHp" and "mXPUSHp".

void  PUSHp(char* str, STRLEN len)

#PUSHpvs

A variation on PUSHp that takes a literal string and calculates its size directly.

void  PUSHpvs("literal string")

#PUSHs

Push an SV onto the stack. The stack must have room for this element. Does not handle 'set' magic. Does not use TARG. See also "PUSHmortal", "XPUSHs", and "XPUSHmortal".

void  PUSHs(SV* sv)

#PUSHu

Push an unsigned integer onto the stack. The stack must have room for this element. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mPUSHu" instead. See also "XPUSHu" and "mXPUSHu".

void  PUSHu(UV uv)

#PUTBACK

Closing bracket for XSUB arguments. This is usually handled by xsubpp. See "PUSHMARK" and perlcall for other uses.

PUTBACK;

#SAVEt_INT

Described in perlguts.

#SP

Stack pointer. This is usually handled by xsubpp. See "dSP" and SPAGAIN.

#SPAGAIN

Refetch the stack pointer. Used after a callback. See perlcall.

SPAGAIN;

#SSNEW

#SSNEWa

#SSNEWat

#SSNEWt

These each temporarily allocate data on the savestack, returning an SSize_t index into the savestack, because a pointer would get broken if the savestack is moved on reallocation. Use "SSPTR" to convert the returned index into a pointer.

The forms differ in that plain SSNEW allocates size bytes; SSNEWt and SSNEWat allocate size objects, each of which is type type; and <SSNEWa> and SSNEWat make sure to align the new data to an align boundary. The most useful value for the alignment is likely to be "MEM_ALIGNBYTES". The alignment will be preserved through savestack reallocation only if realloc returns data aligned to a size divisible by "align"!

SSize_t  SSNEW  (Size_t size)
SSize_t  SSNEWa (Size_t size, Size_t align)
SSize_t  SSNEWat(Size_t size, type, Size_t align)
SSize_t  SSNEWt (Size_t size, type)

#SSPTR

#SSPTRt

These convert the index returned by L/<SSNEW> and kin into actual pointers.

The difference is that SSPTR casts the result to type, and SSPTRt casts it to a pointer of that type.

type    SSPTR (SSize_t index, type)
type *  SSPTRt(SSize_t index, type)

#TARG

TARG is short for "target". It is an entry in the pad that an OPs op_targ refers to. It is scratchpad space, often used as a return value for the OP, but some use it for other purposes.

TARG;

#TOPs

Described in perlguts.

#XPUSHi

Push an integer onto the stack, extending the stack if necessary. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mXPUSHi" instead. See also "PUSHi" and "mPUSHi".

void  XPUSHi(IV iv)

#XPUSHmortal

Push a new mortal SV onto the stack, extending the stack if necessary. Does not use TARG. See also "XPUSHs", "PUSHmortal" and "PUSHs".

void  XPUSHmortal

#XPUSHn

Push a double onto the stack, extending the stack if necessary. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mXPUSHn" instead. See also "PUSHn" and "mPUSHn".

void  XPUSHn(NV nv)

#XPUSHp

Push a string onto the stack, extending the stack if necessary. The len indicates the length of the string. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mXPUSHp" instead. See also "PUSHp" and "mPUSHp".

void  XPUSHp(char* str, STRLEN len)

#XPUSHpvs

A variation on XPUSHp that takes a literal string and calculates its size directly.

void  XPUSHpvs("literal string")

#XPUSHs

Push an SV onto the stack, extending the stack if necessary. Does not handle 'set' magic. Does not use TARG. See also "XPUSHmortal", PUSHs and PUSHmortal.

void  XPUSHs(SV* sv)

#XPUSHu

Push an unsigned integer onto the stack, extending the stack if necessary. Handles 'set' magic. Uses TARG, so dTARGET or dXSTARG should be called to declare it. Do not call multiple TARG-oriented macros to return lists from XSUB's - see "mXPUSHu" instead. See also "PUSHu" and "mPUSHu".

void  XPUSHu(UV uv)

#XS_APIVERSION_BOOTCHECK

Macro to verify that the perl api version an XS module has been compiled against matches the api version of the perl interpreter it's being loaded into.

XS_APIVERSION_BOOTCHECK;

#XS_VERSION

The version identifier for an XS module. This is usually handled automatically by ExtUtils::MakeMaker. See "XS_VERSION_BOOTCHECK".

#XS_VERSION_BOOTCHECK

Macro to verify that a PM module's $VERSION variable matches the XS module's XS_VERSION variable. This is usually handled automatically by xsubpp. See "The VERSIONCHECK: Keyword" in perlxs.

XS_VERSION_BOOTCHECK;

#XSRETURN

Return from XSUB, indicating number of items on the stack. This is usually handled by xsubpp.

void  XSRETURN(int nitems)

#XSRETURN_EMPTY

Return an empty list from an XSUB immediately.

XSRETURN_EMPTY;

#XSRETURN_IV

Return an integer from an XSUB immediately. Uses XST_mIV.

void  XSRETURN_IV(IV iv)

#XSRETURN_NO

Return &PL_sv_no from an XSUB immediately. Uses XST_mNO.

XSRETURN_NO;

#XSRETURN_NV

Return a double from an XSUB immediately. Uses XST_mNV.

void  XSRETURN_NV(NV nv)

#XSRETURN_PV

Return a copy of a string from an XSUB immediately. Uses XST_mPV.

void  XSRETURN_PV(char* str)

#XSRETURN_UNDEF

Return &PL_sv_undef from an XSUB immediately. Uses XST_mUNDEF.

XSRETURN_UNDEF;

#XSRETURN_UV

Return an integer from an XSUB immediately. Uses XST_mUV.

void  XSRETURN_UV(IV uv)

#XSRETURN_YES

Return &PL_sv_yes from an XSUB immediately. Uses XST_mYES.

XSRETURN_YES;

#XST_mIV

Place an integer into the specified position pos on the stack. The value is stored in a new mortal SV.

void  XST_mIV(int pos, IV iv)

#XST_mNO

Place &PL_sv_no into the specified position pos on the stack.

void  XST_mNO(int pos)

#XST_mNV

Place a double into the specified position pos on the stack. The value is stored in a new mortal SV.

void  XST_mNV(int pos, NV nv)

#XST_mPV

Place a copy of a string into the specified position pos on the stack. The value is stored in a new mortal SV.

void  XST_mPV(int pos, char* str)

#XST_mUNDEF

Place &PL_sv_undef into the specified position pos on the stack.

void  XST_mUNDEF(int pos)

#XST_mUV

Place an unsigned integer into the specified position pos on the stack. The value is stored in a new mortal SV.

void  XST_mUV(int pos, UV uv)

#XST_mYES

Place &PL_sv_yes into the specified position pos on the stack.

void  XST_mYES(int pos)

#String Handling

See also "Unicode Support".

#Copy

#CopyD

The XSUB-writer's interface to the C memcpy function. The src is the source, dest is the destination, nitems is the number of items, and type is the type. May fail on overlapping copies. See also "Move".

CopyD is like Copy but returns dest. Useful for encouraging compilers to tail-call optimise.

void    Copy (void* src, void* dest, int nitems, type)
void *  CopyD(void* src, void* dest, int nitems, type)

#delimcpy

Copy a source buffer to a destination buffer, stopping at (but not including) the first occurrence in the source of an unescaped (defined below) delimiter byte, delim. The source is the bytes between from and from_end - 1. Similarly, the dest is to up to to_end.

The number of bytes copied is written to *retlen.

Returns the position of the first uncopied delim in the from buffer, but if there is no such occurrence before from_end, then from_end is returned, and the entire buffer from .. from_end - 1 is copied.

If there is room in the destination available after the copy, an extra terminating safety NUL byte is appended (not included in the returned length).

The error case is if the destination buffer is not large enough to accommodate everything that should be copied. In this situation, a value larger than to_end - to is written to *retlen, and as much of the source as fits will be written to the destination. Not having room for the safety NUL is not considered an error.

In the following examples, let x be the delimiter, and 0 represent a NUL byte (NOT the digit 0). Then we would have

 Source     Destination
abcxdef        abc0

provided the destination buffer is at least 4 bytes long.

An escaped delimiter is one which is immediately preceded by a single backslash. Escaped delimiters are copied, and the copy continues past the delimiter; the backslash is not copied:

 Source       Destination
abc\xdef       abcxdef0

(provided the destination buffer is at least 8 bytes long).

It's actually somewhat more complicated than that. A sequence of any odd number of backslashes escapes the following delimiter, and the copy continues with exactly one of the backslashes stripped.

    Source         Destination
    abc\xdef          abcxdef0
  abc\\\xdef        abc\\xdef0
abc\\\\\xdef      abc\\\\xdef0

(as always, if the destination is large enough)

An even number of preceding backslashes does not escape the delimiter, so that the copy stops just before it, and includes all the backslashes (no stripping; zero is considered even):

    Source         Destination
    abcxdef          abc0
  abc\\xdef          abc\\0
abc\\\\xdef          abc\\\\0

char *       delimcpy(char *to, const char *to_end,
                      const char *from, const char *from_end,
                      const int delim, I32 *retlen)
char *  Perl_delimcpy(char *to, const char *to_end,
                      const char *from, const char *from_end,
                      const int delim, I32 *retlen)

#do_join

This performs a Perl join, placing the joined output into sv.

The elements to join are in SVs, stored in a C array of pointers to SVs, from **mark to **sp - 1. Hence *mark is a reference to the first SV. Each SV will be coerced into a PV if not one already.

delim contains the string (or coerced into a string) that is to separate each of the joined elements.

If any component is in UTF-8, the result will be as well, and all non-UTF-8 components will be converted to UTF-8 as necessary.

Magic and tainting are handled.

void       do_join(      SV *sv, SV *delim, SV **mark, SV **sp)
void  Perl_do_join(pTHX_ SV *sv, SV *delim, SV **mark, SV **sp)

#do_sprintf

This performs a Perl sprintf placing the string output into sv.

The elements to format are in SVs, stored in a C array of pointers to SVs of length len> and beginning at **sarg. The element referenced by *sarg is the format.

Magic and tainting are handled.

void       do_sprintf(      SV *sv, SSize_t len, SV **sarg)
void  Perl_do_sprintf(pTHX_ SV *sv, SSize_t len, SV **sarg)

#fbm_compile

Analyzes the string in order to make fast searches on it using fbm_instr() -- the Boyer-Moore algorithm.

void       fbm_compile(      SV *sv, U32 flags)
void  Perl_fbm_compile(pTHX_ SV *sv, U32 flags)

#fbm_instr

Returns the location of the SV in the string delimited by big and bigend (bigend) is the char following the last char). It returns NULL if the string can't be found. The sv does not have to be fbm_compiled, but the search will not be as fast then.

char *       fbm_instr(      unsigned char *big,
                             unsigned char *bigend,
                             SV *littlestr, U32 flags)
char *  Perl_fbm_instr(pTHX_ unsigned char *big,
                             unsigned char *bigend,
                             SV *littlestr, U32 flags)

#foldEQ

#foldEQ_locale

These each return true if the leading len bytes of the strings s1 and s2 are the same case-insensitively; false otherwise.

In foldEQ, uppercase and lowercase ASCII range bytes match themselves and their opposite case counterparts. Non-cased and non-ASCII range bytes match only themselves.

In foldEQ_locale, the comparison is based on the current locale. If that locale is UTF-8, the results are the same as foldEQ, leading to incorrect values for non-ASCII range code points. Use "foldEQ_utf8" instead.

I32       foldEQ       (      const char *a, const char *b,
                              I32 len)
I32  Perl_foldEQ       (pTHX_ const char *a, const char *b,
                              I32 len)
I32       foldEQ_locale(      const char *a, const char *b,
                              I32 len)
I32  Perl_foldEQ_locale(pTHX_ const char *a, const char *b,
                              I32 len)

#ibcmp

#ibcmp_locale

#ibcmp_utf8

These return the complement of "foldEQ", "foldEQ_locale", and "foldEQ_utf8" respectively. Those other names are preferred, as being clearer.

Hence, for example, ibcmp() is (! foldEQ())

I32  ibcmp       (const char *a, const char *b, I32 len)
I32  ibcmp_locale(const char *a, const char *b, I32 len)
I32  ibcmp_utf8  (const char *s1, char **pe1, UV l1, bool u1,
                  const char *s2, char **pe2, UV l2, bool u2)

#instr

Same as strstr(3), which finds and returns a pointer to the first occurrence of the NUL-terminated substring little in the NUL-terminated string big, returning NULL if not found. The terminating NUL bytes are not compared.

char *       instr(const char *big, const char *little)
char *  Perl_instr(const char *big, const char *little)

#memCHRs

Returns the position of the first occurrence of the byte c in the literal string "list", or NULL if c doesn't appear in "list". All bytes are treated as unsigned char. Thus this macro can be used to determine if c is in a set of particular characters. Unlike strchr(3), it works even if c is NUL (and the set doesn't include NUL).

bool  memCHRs("list", char c)

#memEQ

Test two buffers (which may contain embedded NUL characters, to see if they are equal. The len parameter indicates the number of bytes to compare. Returns true or false. It is undefined behavior if either of the buffers doesn't contain at least len bytes.

bool  memEQ(char* s1, char* s2, STRLEN len)

#memEQs

Like "memEQ", but the second string is a literal enclosed in double quotes, l1 gives the number of bytes in s1. Returns true or false.

bool  memEQs(char* s1, STRLEN l1, "s2")

#memNE

Test two buffers (which may contain embedded NUL characters, to see if they are not equal. The len parameter indicates the number of bytes to compare. Returns true or false. It is undefined behavior if either of the buffers doesn't contain at least len bytes.

bool  memNE(char* s1, char* s2, STRLEN len)

#memNEs

Like "memNE", but the second string is a literal enclosed in double quotes, l1 gives the number of bytes in s1. Returns true or false.

bool  memNEs(char* s1, STRLEN l1, "s2")

#Move

#MoveD

The XSUB-writer's interface to the C memmove function. The src is the source, dest is the destination, nitems is the number of items, and type is the type. Can do overlapping moves. See also "Copy".

MoveD is like Move but returns dest. Useful for encouraging compilers to tail-call optimise.

void    Move (void* src, void* dest, int nitems, type)
void *  MoveD(void* src, void* dest, int nitems, type)

#my_snprintf

The C library snprintf functionality, if available and standards-compliant (uses vsnprintf, actually). However, if the vsnprintf is not available, will unfortunately use the unsafe vsprintf which can overrun the buffer (there is an overrun check, but that may be too late). Consider using sv_vcatpvf instead, or getting vsnprintf.

int       my_snprintf(char *buffer, const Size_t len,
                      const char *format, ...)
int  Perl_my_snprintf(char *buffer, const Size_t len,
                      const char *format, ...)

#my_sprintf

DEPRECATED! It is planned to remove my_sprintf from a future release of Perl. Do not use it for new code; remove it from existing code.

Do NOT use this due to the possibility of overflowing buffer. Instead use my_snprintf()

int  my_sprintf(char *buffer, const char *pat, ...)

#my_strlcat

The C library strlcat if available, or a Perl implementation of it. This operates on C NUL-terminated strings.

my_strlcat() appends string src to the end of dst. It will append at most size - strlen(dst) - 1 bytes. It will then NUL-terminate, unless size is 0 or the original dst string was longer than size (in practice this should not happen as it means that either size is incorrect or that dst is not a proper NUL-terminated string).

Note that size is the full size of the destination buffer and the result is guaranteed to be NUL-terminated if there is room. Note that room for the NUL should be included in size.

The return value is the total length that dst would have if size is sufficiently large. Thus it is the initial length of dst plus the length of src. If size is smaller than the return, the excess was not appended.

Size_t       my_strlcat(char *dst, const char *src, Size_t size)
Size_t  Perl_my_strlcat(char *dst, const char *src, Size_t size)

#my_strlcpy

The C library strlcpy if available, or a Perl implementation of it. This operates on C NUL-terminated strings.

my_strlcpy() copies up to size - 1 bytes from the string src to dst, NUL-terminating the result if size is not 0.

The return value is the total length src would be if the copy completely succeeded. If it is larger than size, the excess was not copied.

Size_t  my_strlcpy(char *dst, const char *src, Size_t size)

#my_strnlen

The C library strnlen if available, or a Perl implementation of it.

my_strnlen() computes the length of the string, up to maxlen bytes. It will never attempt to address more than maxlen bytes, making it suitable for use with strings that are not guaranteed to be NUL-terminated.

Size_t       my_strnlen(const char *str, Size_t maxlen)
Size_t  Perl_my_strnlen(const char *str, Size_t maxlen)

#my_vsnprintf

The C library vsnprintf if available and standards-compliant. However, if the vsnprintf is not available, will unfortunately use the unsafe vsprintf which can overrun the buffer (there is an overrun check, but that may be too late). Consider using sv_vcatpvf instead, or getting vsnprintf.

int       my_vsnprintf(char *buffer, const Size_t len,
                       const char *format, va_list ap)
int  Perl_my_vsnprintf(char *buffer, const Size_t len,
                       const char *format, va_list ap)

#NewCopy

Combines Newx() and Copy() into a single macro. Dest will be allocated using Newx() and then src will be copied into it.

void  NewCopy(void* src, void* dest, int nitems, type)

#ninstr

Find the first (leftmost) occurrence of a sequence of bytes within another sequence. This is the Perl version of strstr(), extended to handle arbitrary sequences, potentially containing embedded NUL characters (NUL is what the initial n in the function name stands for; some systems have an equivalent, memmem(), but with a somewhat different API).

Another way of thinking about this function is finding a needle in a haystack. big points to the first byte in the haystack. big_end points to one byte beyond the final byte in the haystack. little points to the first byte in the needle. little_end points to one byte beyond the final byte in the needle. All the parameters must be non-NULL.

The function returns NULL if there is no occurrence of little within big. If little is the empty string, big is returned.

Because this function operates at the byte level, and because of the inherent characteristics of UTF-8 (or UTF-EBCDIC), it will work properly if both the needle and the haystack are strings with the same UTF-8ness, but not if the UTF-8ness differs.

char *       ninstr(const char *big, const char *bigend,
                    const char *little, const char *lend)
char *  Perl_ninstr(const char *big, const char *bigend,
                    const char *little, const char *lend)

#Nullch

Null character pointer. (No longer available when PERL_CORE is defined.)

#PL_na

A scratch pad variable in which to store a STRLEN value. If would have been better named something like PL_temp_strlen.

It is is typically used with SvPV when one is actually planning to discard the returned length, (hence the length is "Not Applicable", which is how this variable got its name).

BUT BEWARE, if this is used in a situation where something that is using it is in a call stack with something else that is using it, this variable would get zapped, leading to hard-to-diagnose errors.

It is usually more efficient to either declare a local variable and use that instead, or to use the SvPV_nolen macro.

STRLEN  PL_na

#rninstr

Like "ninstr", but instead finds the final (rightmost) occurrence of a sequence of bytes within another sequence, returning NULL if there is no such occurrence.

char *       rninstr(const char *big, const char *bigend,
                     const char *little, const char *lend)
char *  Perl_rninstr(const char *big, const char *bigend,
                     const char *little, const char *lend)

#savepv

#savepvn

#savepvs

#savesvpv

#savesharedpv

#savesharedpvn

#savesharedpvs

#savesharedsvpv

Perl's version of strdup() (or strndup() would be if it existed).

These each return a pointer to a newly allocated string which is a duplicate of the input string.

The forms differ in how the string to be copied is specified, and where the new memory is allocated from.

To prevent memory leaks, the memory allocated for the new string needs to be freed when no longer needed. This can be done with the "Safefree" function, or SAVEFREEPV.

The forms whose names contain shared differ from the corresponding form without that in its name, only in that the memory in the former comes from memory shared between threads. This is needed, because on some platforms, Windows for example, all allocated memory owned by a thread is deallocated when that thread ends. So if you need that not to happen, you need to use the shared memory forms.

The string to copy in savepvs is a C language string literal surrounded by double quotes.

The string to copy in the forms whose name contains svpv comes from the PV in the SV argument sv, using SvPV()

The string to copy in the remaining forms comes from the pv argument.

In the case of savepv, the size of the string is determined by strlen(), which means it may not contain embedded NUL characters, and must have a trailing NUL.

In the case of savepvn, len gives the length of pv, hence it may contain embedded NUL characters. The copy will be guaranteed to have a trailing NUL added if not already present.

char *       savepv        (      const char *pv)
char *  Perl_savepv        (pTHX_ const char *pv)
char *       savepvn       (      const char *pv, Size_t len)
char *  Perl_savepvn       (pTHX_ const char *pv, Size_t len)
char*        savepvs       (      "literal string")
char *       savesvpv      (      SV *sv)
char *  Perl_savesvpv      (pTHX_ SV *sv)
char *       savesharedpv  (      const char *pv)
char *  Perl_savesharedpv  (pTHX_ const char *pv)
char *       savesharedpvn (      const char * const pv,
                                  const STRLEN len)
char *  Perl_savesharedpvn (pTHX_ const char * const pv,
                                  const STRLEN len)
char*        savesharedpvs (      "literal string")
char *       savesharedsvpv(      SV *sv)
char *  Perl_savesharedsvpv(pTHX_ SV *sv)

#STR_WITH_LEN

Returns two comma separated tokens of the input literal string, and its length. This is convenience macro which helps out in some API calls. Note that it can't be used as an argument to macros or functions that under some configurations might be macros, which means that it requires the full Perl_xxx(aTHX_ ...) form for any API calls where it's used.

pair  STR_WITH_LEN("literal string")

#strEQ

Test two NUL-terminated strings to see if they are equal. Returns true or false.

bool  strEQ(char* s1, char* s2)

#strGE

Test two NUL-terminated strings to see if the first, s1, is greater than or equal to the second, s2. Returns true or false.

bool  strGE(char* s1, char* s2)

#strGT

Test two NUL-terminated strings to see if the first, s1, is greater than the second, s2. Returns true or false.

bool  strGT(char* s1, char* s2)

#strLE

Test two NUL-terminated strings to see if the first, s1, is less than or equal to the second, s2. Returns true or false.

bool  strLE(char* s1, char* s2)

#STRLEN

Described in perlguts.

#strLT

Test two NUL-terminated strings to see if the first, s1, is less than the second, s2. Returns true or false.

bool  strLT(char* s1, char* s2)

#strNE

Test two NUL-terminated strings to see if they are different. Returns true or false.

bool  strNE(char* s1, char* s2)

#strnEQ

Test two NUL-terminated strings to see if they are equal. The len parameter indicates the number of bytes to compare. Returns true or false. (A wrapper for strncmp).

bool  strnEQ(char* s1, char* s2, STRLEN len)

#strnNE

Test two NUL-terminated strings to see if they are different. The len parameter indicates the number of bytes to compare. Returns true or false. (A wrapper for strncmp).

bool  strnNE(char* s1, char* s2, STRLEN len)

#Zero

#ZeroD

The XSUB-writer's interface to the C memzero function. The dest is the destination, nitems is the number of items, and type is the type.

ZeroD is like Zero but returns dest. Useful for encouraging compilers to tail-call optimise.

void    Zero (void* dest, int nitems, type)
void *  ZeroD(void* dest, int nitems, type)

#SV Flags

#SVt_IV

#SVt_NULL

#SVt_NV

#SVt_PV

Type flag for scalars. See "svtype".

#SVt_PVAV

Type flag for arrays. See "svtype".

#SVt_PVCV

Type flag for subroutines. See "svtype".

#SVt_PVFM

Type flag for formats. See "svtype".

#SVt_PVGV

Type flag for typeglobs. See "svtype".

#SVt_PVHV

Type flag for hashes. See "svtype".

#SVt_PVIO

Type flag for I/O objects. See "svtype".

#SVt_PVIV

#SVt_PVLV

#SVt_PVMG

#SVt_PVNV

Type flag for scalars. See "svtype".

#SVt_PVOBJ

NOTE: SVt_PVOBJ is experimental and may change or be removed without notice.

Type flag for object instances. See "svtype".

#SVt_REGEXP

Type flag for regular expressions. See "svtype".

#svtype

An enum of flags for Perl types. These are found in the file sv.h in the svtype enum. Test these flags with the SvTYPE macro.

The types are:

SVt_NULL
SVt_IV
SVt_NV
SVt_RV
SVt_PV
SVt_PVIV
SVt_PVNV
SVt_PVMG
SVt_INVLIST
SVt_REGEXP
SVt_PVGV
SVt_PVLV
SVt_PVAV
SVt_PVHV
SVt_PVCV
SVt_PVFM
SVt_PVIO
SVt_PVOBJ

These are most easily explained from the bottom up.

SVt_PVOBJ is for object instances of the new `use feature 'class'` kind. SVt_PVIO is for I/O objects, SVt_PVFM for formats, SVt_PVCV for subroutines, SVt_PVHV for hashes and SVt_PVAV for arrays.

All the others are scalar types, that is, things that can be bound to a $ variable. For these, the internal types are mostly orthogonal to types in the Perl language.

Hence, checking SvTYPE(sv) < SVt_PVAV is the best way to see whether something is a scalar.

SVt_PVGV represents a typeglob. If !SvFAKE(sv), then it is a real, incoercible typeglob. If SvFAKE(sv), then it is a scalar to which a typeglob has been assigned. Assigning to it again will stop it from being a typeglob. SVt_PVLV represents a scalar that delegates to another scalar behind the scenes. It is used, e.g., for the return value of substr and for tied hash and array elements. It can hold any scalar value, including a typeglob. SVt_REGEXP is for regular expressions. SVt_INVLIST is for Perl core internal use only.

SVt_PVMG represents a "normal" scalar (not a typeglob, regular expression, or delegate). Since most scalars do not need all the internal fields of a PVMG, we save memory by allocating smaller structs when possible. All the other types are just simpler forms of SVt_PVMG, with fewer internal fields. SVt_NULL can only hold undef. SVt_IV can hold undef, an integer, or a reference. (SVt_RV is an alias for SVt_IV, which exists for backward compatibility.) SVt_NV can hold undef or a double. (In builds that support headless NVs, these could also hold a reference via a suitable offset, in the same way that SVt_IV does, but this is not currently supported and seems to be a rare use case.) SVt_PV can hold undef, a string, or a reference. SVt_PVIV is a superset of SVt_PV and SVt_IV. SVt_PVNV is a superset of SVt_PV and SVt_NV. SVt_PVMG can hold anything SVt_PVNV can hold, but it may also be blessed or magical.

#SV Handling

#AV_FROM_REF

#CV_FROM_REF

#GV_FROM_REF

#HV_FROM_REF

The *V_FROM_REF macros extract the SvRV() from a given reference SV and return a suitably-cast to pointer to the referenced SV. When running under -DDEBUGGING, assertions are also applied that check that ref is definitely a reference SV that refers to an SV of the right type.

AV *  AV_FROM_REF(SV * ref)
CV *  CV_FROM_REF(SV * ref)
GV *  GV_FROM_REF(SV * ref)
HV *  HV_FROM_REF(SV * ref)

#BOOL_INTERNALS_sv_isbool

Checks if a SvBoolFlagsOK() sv is a bool. Note that it is the caller's responsibility to ensure that the sv is SvBoolFlagsOK() before calling this. This is only useful in specialized logic like serialization code where performance is critical and the flags have already been checked to be correct. Almost always you should be using sv_isbool(sv) instead.

bool  BOOL_INTERNALS_sv_isbool(SV* sv)

#BOOL_INTERNALS_sv_isbool_false

Checks if a SvBoolFlagsOK() sv is a false bool. Note that it is the caller's responsibility to ensure that the sv is SvBoolFlagsOK() before calling this. This is only useful in specialized logic like serialization code where performance is critical and the flags have already been checked to be correct. This is NOT what you should use to check if an SV is "false", for that you should be using !SvTRUE(sv) instead.

bool  BOOL_INTERNALS_sv_isbool_false(SV* sv)

#BOOL_INTERNALS_sv_isbool_true

Checks if a SvBoolFlagsOK() sv is a true bool. Note that it is the caller's responsibility to ensure that the sv is SvBoolFlagsOK() before calling this. This is only useful in specialized logic like serialization code where performance is critical and the flags have already been checked to be correct. This is NOT what you should use to check if an SV is "true", for that you should be using SvTRUE(sv) instead.

bool  BOOL_INTERNALS_sv_isbool_true(SV* sv)

#boolSV

Returns a true SV if b is a true value, or a false SV if b is 0.

See also "PL_sv_yes" and "PL_sv_no".

SV *  boolSV(bool b)

#croak_xs_usage

A specialised variant of croak() for emitting the usage message for xsubs

croak_xs_usage(cv, "eee_yow");

works out the package name and subroutine name from cv, and then calls croak(). Hence if cv is &ouch::awk, it would call croak as:

diag_listed_as: SKIPME
croak("Usage: %" SVf "::%" SVf "(%s)", "ouch" "awk",
                                                    "eee_yow");

void       croak_xs_usage(const CV * const cv,
                          const char * const params)
void  Perl_croak_xs_usage(const CV * const cv,
                          const char * const params)

#CV_FROM_REF*

Described under "AV_FROM_REF"

#DEFSV

Returns the SV associated with $_

SV *  DEFSV

#DEFSV_set

Associate sv with $_

void  DEFSV_set(SV * sv)

#get_sv

Returns the SV of the specified Perl scalar. flags are passed to "gv_fetchpv". If GV_ADD is set and the Perl variable does not exist then it will be created. If flags is zero and the variable does not exist then NULL is returned.

NOTE: the perl_get_sv() form is deprecated.

SV *       get_sv(      const char *name, I32 flags)
SV *  Perl_get_sv(pTHX_ const char *name, I32 flags)

#GV_FROM_REF*

#HV_FROM_REF*

Described under "AV_FROM_REF"

#isGV_with_GP

Returns a boolean as to whether or not sv is a GV with a pointer to a GP (glob pointer).

bool  isGV_with_GP(SV * sv)

#looks_like_number

Test if the content of an SV looks like a number (or is a number). Inf and Infinity are treated as numbers (so will not issue a non-numeric warning), even if your atof() doesn't grok them. Get-magic is ignored.

I32       looks_like_number(      SV * const sv)
I32  Perl_looks_like_number(pTHX_ SV * const sv)

#MUTABLE_AV

#MUTABLE_CV

#MUTABLE_GV

#MUTABLE_HV

#MUTABLE_IO

#MUTABLE_PTR

#MUTABLE_SV

The MUTABLE_*() macros cast pointers to the types shown, in such a way (compiler permitting) that casting away const-ness will give a warning; e.g.:

const SV *sv = ...;
AV *av1 = (AV*)sv;        <== BAD:  the const has been silently
                                    cast away
AV *av2 = MUTABLE_AV(sv); <== GOOD: it may warn

MUTABLE_PTR is the base macro used to derive new casts. The other already-built-in ones return pointers to what their names indicate.

AV *    MUTABLE_AV (AV * p)
CV *    MUTABLE_CV (CV * p)
GV *    MUTABLE_GV (GV * p)
HV *    MUTABLE_HV (HV * p)
IO *    MUTABLE_IO (IO * p)
void *  MUTABLE_PTR(void * p)
SV *    MUTABLE_SV (SV * p)

#newRV

#newRV_inc

These are identical. They create an RV wrapper for an SV. The reference count for the original SV is incremented.

SV *       newRV    (      SV * const sv)
SV *  Perl_newRV    (pTHX_ SV * const sv)
SV *       newRV_inc(      SV * const sv)

#newRV_noinc

Creates an RV wrapper for an SV. The reference count for the original SV is not incremented.

SV *       newRV_noinc(      SV * const tmpRef)
SV *  Perl_newRV_noinc(pTHX_ SV * const tmpRef)

#newSV

Creates a new SV. A non-zero len parameter indicates the number of bytes of preallocated string space the SV should have. An extra byte for a trailing NUL is also reserved. (SvPOK is not set for the SV even if string space is allocated.) The reference count for the new SV is set to 1.

In 5.9.3, newSV() replaces the older NEWSV() API, and drops the first parameter, x, a debug aid which allowed callers to identify themselves. This aid has been superseded by a new build option, PERL_MEM_LOG (see "PERL_MEM_LOG" in perlhacktips). The older API is still there for use in XS modules supporting older perls.

SV *       newSV(      const STRLEN len)
SV *  Perl_newSV(pTHX_ const STRLEN len)

#newSV_false

Creates a new SV that is a boolean false.

SV *       newSV_false()
SV *  Perl_newSV_false(pTHX)

#newSV_true

Creates a new SV that is a boolean true.

SV *       newSV_true()
SV *  Perl_newSV_true(pTHX)

#newSV_type

Creates a new SV, of the type specified. The reference count for the new SV is set to 1.

SV *       newSV_type(      const svtype type)
SV *  Perl_newSV_type(pTHX_ const svtype type)

#newSV_type_mortal

Creates a new mortal SV, of the type specified. The reference count for the new SV is set to 1.

This is equivalent to SV* sv = sv_2mortal(newSV_type(<some type>)) and SV* sv = sv_newmortal(); sv_upgrade(sv, <some_type>) but should be more efficient than both of them. (Unless sv_2mortal is inlined at some point in the future.)

SV *       newSV_type_mortal(      const svtype type)
SV *  Perl_newSV_type_mortal(pTHX_ const svtype type)

#newSVbool

Creates a new SV boolean.

SV *       newSVbool(      const bool bool_val)
SV *  Perl_newSVbool(pTHX_ const bool bool_val)

#newSVhek

Creates a new SV from the hash key structure. It will generate scalars that point to the shared string table where possible. Returns a new (undefined) SV if hek is NULL.

SV *       newSVhek(      const HEK * const hek)
SV *  Perl_newSVhek(pTHX_ const HEK * const hek)

#newSVhek_mortal

Creates a new mortal SV from the hash key structure. It will generate scalars that point to the shared string table where possible. Returns a new (undefined) SV if hek is NULL.

This is more efficient than using sv_2mortal(newSVhek( ... ))

SV *       newSVhek_mortal(      const HEK * const hek)
SV *  Perl_newSVhek_mortal(pTHX_ const HEK * const hek)

#newSViv

Creates a new SV and copies an integer into it. The reference count for the SV is set to 1.

SV *       newSViv(      const IV i)
SV *  Perl_newSViv(pTHX_ const IV i)

#newSVnv

Creates a new SV and copies a floating point value into it. The reference count for the SV is set to 1.

SV *       newSVnv(      const NV n)
SV *  Perl_newSVnv(pTHX_ const NV n)

#newSVpadname

NOTE: newSVpadname is experimental and may change or be removed without notice.

Creates a new SV containing the pad name.

SV*  newSVpadname(PADNAME *pn)

#newSVpv

Creates a new SV and copies a string (which may contain NUL (\0) characters) into it. The reference count for the SV is set to 1. If len is zero, Perl will compute the length using strlen(), (which means if you use this option, that s can't have embedded NUL characters and has to have a terminating NUL byte).

This function can cause reliability issues if you are likely to pass in empty strings that are not null terminated, because it will run strlen on the string and potentially run past valid memory.

Using "newSVpvn" is a safer alternative for non NUL terminated strings. For string literals use "newSVpvs" instead. This function will work fine for NUL terminated strings, but if you want to avoid the if statement on whether to call strlen use newSVpvn instead (calling strlen yourself).

SV *       newSVpv(      const char * const s, const STRLEN len)
SV *  Perl_newSVpv(pTHX_ const char * const s, const STRLEN len)

#newSVpv_share

Like newSVpvn_share, but takes a NUL-terminated string instead of a string/length pair.

SV *       newSVpv_share(      const char *s, U32 hash)
SV *  Perl_newSVpv_share(pTHX_ const char *s, U32 hash)

#newSVpvf

Creates a new SV and initializes it with the string formatted like sv_catpvf.

SV *  Perl_newSVpvf(pTHX_ const char * const pat, ...)

#newSVpvf_nocontext

Like "newSVpvf" but does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

SV *       newSVpvf_nocontext(const char * const pat, ...)
SV *  Perl_newSVpvf_nocontext(const char * const pat, ...)

#newSVpvn

Creates a new SV and copies a string into it, which may contain NUL characters (\0) and other binary data. The reference count for the SV is set to 1. Note that if len is zero, Perl will create a zero length (Perl) string. You are responsible for ensuring that the source buffer is at least len bytes long. If the buffer argument is NULL the new SV will be undefined.

SV *       newSVpvn(      const char * const s, const STRLEN len)
SV *  Perl_newSVpvn(pTHX_ const char * const s, const STRLEN len)

#newSVpvn_flags

Creates a new SV and copies a string (which may contain NUL (\0) characters) into it. The reference count for the SV is set to 1. Note that if len is zero, Perl will create a zero length string. You are responsible for ensuring that the source string is at least len bytes long. If the s argument is NULL the new SV will be undefined. Currently the only flag bits accepted are SVf_UTF8 and SVs_TEMP. If SVs_TEMP is set, then sv_2mortal() is called on the result before returning. If SVf_UTF8 is set, s is considered to be in UTF-8 and the SVf_UTF8 flag will be set on the new SV. newSVpvn_utf8() is a convenience wrapper for this function, defined as

#define newSVpvn_utf8(s, len, u)			\
    newSVpvn_flags((s), (len), (u) ? SVf_UTF8 : 0)

SV *       newSVpvn_flags(      const char * const s,
                                const STRLEN len,
                                const U32 flags)
SV *  Perl_newSVpvn_flags(pTHX_ const char * const s,
                                const STRLEN len,
                                const U32 flags)

#newSVpvn_share

Creates a new SV with its SvPVX_const pointing to a shared string in the string table. If the string does not already exist in the table, it is created first. Turns on the SvIsCOW flag (or READONLY and FAKE in 5.16 and earlier). If the hash parameter is non-zero, that value is used; otherwise the hash is computed. The string's hash can later be retrieved from the SV with the "SvSHARED_HASH" macro. The idea here is that as the string table is used for shared hash keys these strings will have SvPVX_const == HeKEY and hash lookup will avoid string compare.

SV *       newSVpvn_share(      const char *s, I32 len, U32 hash)
SV *  Perl_newSVpvn_share(pTHX_ const char *s, I32 len, U32 hash)

#newSVpvn_utf8

Creates a new SV and copies a string (which may contain NUL (\0) characters) into it. If utf8 is true, calls SvUTF8_on on the new SV. Implemented as a wrapper around newSVpvn_flags.

SV*  newSVpvn_utf8(const char* s, STRLEN len, U32 utf8)

#newSVpvs

Like newSVpvn, but takes a literal string instead of a string/length pair.

SV*  newSVpvs("literal string")

#newSVpvs_flags

Like newSVpvn_flags, but takes a literal string instead of a string/length pair.

SV*  newSVpvs_flags("literal string", U32 flags)

#newSVpvs_share

Like newSVpvn_share, but takes a literal string instead of a string/length pair and omits the hash parameter.

SV*  newSVpvs_share("literal string")

#newSVpvz

Creates a new SV initialized with an empty string, like newSVpvs(""), but with enough available space to hold a string of len bytes (plus a trailing NUL) without needing to grow. It differs from "newSV" in that the string is defined and initialized.

The reference count for the new SV is set to 1.

SV *       newSVpvz(      const STRLEN len)
SV *  Perl_newSVpvz(pTHX_ const STRLEN len)

#newSVrv

Creates a new SV for the existing RV, rv, to point to. If rv is not an RV then it will be upgraded to one. If classname is non-null then the new SV will be blessed in the specified package. The new SV is returned and its reference count is 1. The reference count 1 is owned by rv. See also newRV_inc() and newRV_noinc() for creating a new RV properly.

SV *       newSVrv(      SV * const rv,
                         const char * const classname)
SV *  Perl_newSVrv(pTHX_ SV * const rv,
                         const char * const classname)

#newSVsv

#newSVsv_flags

#newSVsv_nomg

These create a new SV which is an exact duplicate of the original SV (using sv_setsv.)

They differ only in that newSVsv performs 'get' magic; newSVsv_nomg skips any magic; and newSVsv_flags allows you to explicitly set a flags parameter.

SV *       newSVsv      (      SV * const old)
SV *  Perl_newSVsv      (pTHX_ SV * const old)
SV *       newSVsv_flags(      SV * const old, I32 flags)
SV *  Perl_newSVsv_flags(pTHX_ SV * const old, I32 flags)
SV *       newSVsv_nomg (      SV * const old)

#newSVuv

Creates a new SV and copies an unsigned integer into it. The reference count for the SV is set to 1.

SV *       newSVuv(      const UV u)
SV *  Perl_newSVuv(pTHX_ const UV u)

#Nullsv

Null SV pointer. (No longer available when PERL_CORE is defined.)

#PL_sv_no

This is the false SV. It is readonly. See "PL_sv_yes". Always refer to this as &PL_sv_no.

SV  PL_sv_no

#PL_sv_undef

This is the undef SV. It is readonly. Always refer to this as &PL_sv_undef.

SV  PL_sv_undef

#PL_sv_yes

This is the true SV. It is readonly. See "PL_sv_no". Always refer to this as &PL_sv_yes.

SV  PL_sv_yes

#PL_sv_zero

This readonly SV has a zero numeric value and a "0" string value. It's similar to "PL_sv_no" except for its string value. Can be used as a cheap alternative to mXPUSHi(0) for example. Always refer to this as &PL_sv_zero. Introduced in 5.28.

SV  PL_sv_zero

#SAVE_DEFSV

Localize $_. See "Localizing changes" in perlguts.

void  SAVE_DEFSV

#sortsv

In-place sort an array of SV pointers with the given comparison routine.

Currently this always uses mergesort. See "sortsv_flags" for a more flexible routine.

void       sortsv(      SV **array, size_t num_elts,
                        SVCOMPARE_t cmp)
void  Perl_sortsv(pTHX_ SV **array, size_t num_elts,
                        SVCOMPARE_t cmp)

#sortsv_flags

In-place sort an array of SV pointers with the given comparison routine, with various SORTf_* flag options.

void       sortsv_flags(      SV **array, size_t num_elts,
                              SVCOMPARE_t cmp, U32 flags)
void  Perl_sortsv_flags(pTHX_ SV **array, size_t num_elts,
                              SVCOMPARE_t cmp, U32 flags)

#SV

Described in perlguts.

#sv_backoff

Remove any string offset. You should normally use the SvOOK_off macro wrapper instead.

void       sv_backoff(SV * const sv)
void  Perl_sv_backoff(SV * const sv)

#sv_bless

Blesses an SV into a specified package. The SV must be an RV. The package must be designated by its stash (see "gv_stashpv"). The reference count of the SV is unaffected.

SV *       sv_bless(      SV * const sv,
                          NOCHECK HV * const stash)
SV *  Perl_sv_bless(pTHX_ SV * const sv,
                          NOCHECK HV * const stash)

#sv_catpv

#sv_catpv_flags

#sv_catpv_mg

#sv_catpv_nomg

#sv_catpvn

#sv_catpvn_flags

#sv_catpvn_mg

#sv_catpvn_nomg

#sv_catpvn_nomg_maybeutf8

#sv_catpvs

#sv_catpvs_flags

#sv_catpvs_mg

#sv_catpvs_nomg

These each concatenate a string onto the end of the string which is in dsv. They differ in how the catenated string is specified and in the handling of magic and UTF-8ness.

In the pvs forms, the catenated string is a C language string literal, enclosed in double quotes.

In the pvn forms, sstr points to the first byte of the string to concatenate, and an additional parameter, len, specifies the number of bytes to copy. Hence, sstr may contain embedded-NUL characters. The caller must make sure sstr contains at least len bytes.

In the plain pv forms, the catenated string is a C language NUL-terminated string.

The _mg forms perform both 'get' and 'set' magic on dsv.

The _nomg forms skip all magic.

The other forms perform only 'get' magic.

The _flags forms have an extra parameter, flags, which allows you to also override the UTF-8 handling. By supplying the SV_CATBYTES flag, the appended string is interpreted as plain bytes; by supplying instead the SV_CATUTF8 flag, it will be interpreted as UTF-8, and dsv will be upgraded to UTF-8 if necessary.

sv_catpvn_nomg_maybeutf8 has an extra boolean parameter, is_utf8, which if true indicates that sstr is encoded in UTF-8; otherwise not.

For all other forms, the string appended is assumed to be valid UTF-8 if and only if the dsv has the UTF-8 status set.

void       sv_catpv                (      SV * const dsv,
                                          const char *sstr)
void  Perl_sv_catpv                (pTHX_ SV * const dsv,
                                          const char *sstr)
void       sv_catpv_flags          (      SV * const dsv,
                                          const char *sstr,
                                          const I32 flags)
void  Perl_sv_catpv_flags          (pTHX_ SV * const dsv,
                                          const char *sstr,
                                          const I32 flags)
void       sv_catpv_mg             (     SV * const dsv,
                                         const char * const sstr)
void  Perl_sv_catpv_mg             (pTHX_ SV * const dsv,
                                         const char * const sstr)
void       sv_catpv_nomg           (      SV * const dsv,
                                          const char * sstr
)
void       sv_catpvn               (      SV * const dsv,
                                          const char *sstr,
                                          STRLEN len)
void  Perl_sv_catpvn               (pTHX_ SV * const dsv,
                                          const char *sstr,
                                          STRLEN len)
void       sv_catpvn_flags         (      SV * const dsv,
                                          const char *sstr,
                                          const STRLEN len,
                                          const I32 flags)
void  Perl_sv_catpvn_flags         (pTHX_ SV * const dsv,
                                          const char *sstr,
                                          const STRLEN len,
                                          const I32 flags)
void       sv_catpvn_mg            (      SV * const dsv,
                                          const char *sstr,
                                          STRLEN len)
void  Perl_sv_catpvn_mg            (pTHX_ SV * const dsv,
                                          const char *sstr,
                                          STRLEN len)
void       sv_catpvn_nomg          (      SV * const dsv,
                                          const char * sstr,
                                          const STRLEN len
)
void       sv_catpvn_nomg_maybeutf8(      SV * const dsv,
                                          const char *sstr,
                                          const STRLEN len,
                                          const I32 flags
)
void       sv_catpvs               (      SV * const dsv,
                                          "literal string")
void       sv_catpvs_flags         (      SV * const dsv,
                                          "literal string",
                                          I32 flags)
void       sv_catpvs_mg            (      SV * const dsv,
                                          "literal string")
void       sv_catpvs_nomg          (      SV * const dsv,
                                          "literal string")

#sv_catpvf

#sv_catpvf_nocontext

#sv_catpvf_mg

#sv_catpvf_mg_nocontext

#sv_vcatpvf

#sv_vcatpvf_mg

#sv_vcatpvfn

#sv_vcatpvfn_flags

These each append to sv the result of formatting their arguments using pat as the sprintf-like pattern. They assume that pat has the same UTF8ness as sv. It's the caller's responsibility to ensure that this is so.

If the destination sv isn't already in UTF-8, but the appended data contains "wide" characters, sv will be converted to be UTF-8. An example is the %c format with the code point > 255. (This is an enhancement to what libc sprintf would do in this situation.) Other examples are given below.

The forms differ in how their arguments are specified and in the handling of magic.

sv_vcatpvfn_flags is the most general, and all the other forms are implemented by eventually calling it.

It has two sets of argument lists, only one of which is used in any given call. The first set, args, is an encapsulated argument list of pointers to C strings. If it is NULL, the other list, svargs, is used; it is an array of pointers to SV's. sv_count gives how many there are in the list.

See sprintf(3) for details on how the formatting is done. Some platforms support extensions to the standard C99 definition of this function. None of those are supported by Perl. For example, neither ' (to get digit grouping), nor I (to get alternate digits) are supported.

Also, argument reordering (using format specifiers like %2$d or %*2$d) is supported only when using the svargs array of SVs; an exception is raised if arg is not NULL and pat contains the $ reordering specifier.

* maybe_tainted is supposed to be set when running with taint checks enabled if the results are untrustworthy (often due to the use of locales). However, this is not currently implemented. This argument is not used.

patlen gives the length in bytes of pat. Currently, the pattern must be NUL-terminated anyway.

flags is used to specify which magic to handle or to skip, by setting or clearing the SV_GMAGIC and/or SV_SMAGIC flags.

Plain sv_vcatpvfn just calls sv_vcatpvfn_flags setting both the SV_GMAGIC and SV_SMAGIC flags, so it always handles both set and get magic.

All the remaining forms handle 'get' magic; the forms whose name contains _mg additionally handle 'set' magic.

When using the svargs array, if any of the SVs in it have their UTF-8 flag set, sv will be converted to be so too, as necessary.

None of the remaining forms use the svargs array, meaning argument reordering is not possible with them. The arguments are generally considered to be the same UTF8ness as the destination sv, though certain Perl extensions to the standard set of %formats can override this (see "Formatted Printing of Strings" in perlguts and adjacent sections).

The forms whose name contains _no_context do not take a thread context (aTHX) parameter, so are used in situations where the caller doesn't already have the thread context.

The forms whose name contains vcat use an encapsulated argument list, the other forms use sprintf-style arguments.

There are no other differences between the forms.

void  Perl_sv_catpvf             (pTHX_ SV * const sv,
                                        const char * const pat,
                                        ...)
void       sv_catpvf_nocontext   (      SV * const sv,
                                        const char * const pat,
                                        ...)
void  Perl_sv_catpvf_nocontext   (      SV * const sv,
                                        const char * const pat,
                                        ...)
void  Perl_sv_catpvf_mg          (pTHX_ SV * const sv,
                                        const char * const pat,
                                        ...)
void       sv_catpvf_mg_nocontext(      SV * const sv,
                                        const char * const pat,
                                        ...)
void  Perl_sv_catpvf_mg_nocontext(      SV * const sv,
                                        const char * const pat,
                                        ...)
void       sv_vcatpvf            (      SV * const sv,
                                        const char * const pat,
                                        va_list * const args)
void  Perl_sv_vcatpvf            (pTHX_ SV * const sv,
                                        const char * const pat,
                                        va_list * const args)
void       sv_vcatpvf_mg         (      SV * const sv,
                                        const char * const pat,
                                        va_list * const args)
void  Perl_sv_vcatpvf_mg         (pTHX_ SV * const sv,
                                        const char * const pat,
                                        va_list * const args)
void       sv_vcatpvfn           (    SV * const sv,
                                      const char * const pat,
                                      const STRLEN patlen,
                                      va_list * const args,
                                      SV ** const svargs,
                                      const Size_t sv_count,
                                      bool * const maybe_tainted)
void  Perl_sv_vcatpvfn           (pTHX_ SV * const sv,
                                      const char * const pat,
                                      const STRLEN patlen,
                                      va_list * const args,
                                      SV ** const svargs,
                                      const Size_t sv_count,
                                      bool * const maybe_tainted)
void       sv_vcatpvfn_flags     (    SV * const sv,
                                      const char * const pat,
                                      const STRLEN patlen,
                                      va_list * const args,
                                      SV ** const svargs,
                                      const Size_t sv_count,
                                      bool * const maybe_tainted,
                                      const U32 flags)
void  Perl_sv_vcatpvfn_flags     (pTHX_ SV * const sv,
                                      const char * const pat,
                                      const STRLEN patlen,
                                      va_list * const args,
                                      SV ** const svargs,
                                      const Size_t sv_count,
                                      bool * const maybe_tainted,
                                      const U32 flags)

#sv_catpvn*

#sv_catpvn_flags*

#sv_catpvn_mg*

#sv_catpvn_nomg*

#sv_catpvn_nomg_maybeutf8*

#sv_catpvs*

#sv_catpvs_flags*

#sv_catpvs_mg*

#sv_catpvs_nomg*

Described under "sv_catpv"

#sv_catsv

#sv_catsv_flags

#sv_catsv_mg

#sv_catsv_nomg

These concatenate the string from SV sstr onto the end of the string in SV dsv. If sstr is null, these are no-ops; otherwise only dsv is modified.

They differ only in what magic they perform:

sv_catsv_mg performs 'get' magic on both SVs before the copy, and 'set' magic on dsv afterwards.

sv_catsv performs just 'get' magic, on both SVs.

sv_catsv_nomg skips all magic.

sv_catsv_flags has an extra flags parameter which allows you to use SV_GMAGIC and/or SV_SMAGIC to specify any combination of magic handling (although either both or neither SV will have 'get' magic applied to it.)

sv_catsv, sv_catsv_mg, and sv_catsv_nomg are implemented in terms of sv_catsv_flags.

void       sv_catsv      (      SV * const dsv, SV * const sstr)
void  Perl_sv_catsv      (pTHX_ SV * const dsv, SV * const sstr)
void       sv_catsv_flags(      SV * const dsv, SV * const sstr,
                                const I32 flags)
void  Perl_sv_catsv_flags(pTHX_ SV * const dsv, SV * const sstr,
                                const I32 flags)
void       sv_catsv_mg   (      SV * const dsv, SV * const sstr)
void  Perl_sv_catsv_mg   (pTHX_ SV * const dsv, SV * const sstr)
void       sv_catsv_nomg (      SV * const dsv, SV * const sstr)

#SV_CHECK_THINKFIRST

Remove any encumbrances from sv, that need to be taken care of before it is modifiable. For example if it is Copy on Write (COW), now is the time to make that copy.

If you know that you are about to change the PV value of sv, instead use "SV_CHECK_THINKFIRST_COW_DROP" to avoid the write that would be immediately written again.

void  SV_CHECK_THINKFIRST(SV * sv)

#SV_CHECK_THINKFIRST_COW_DROP

Call this when you are about to replace the PV value in sv, which is potentially copy-on-write. It stops any sharing with other SVs, so that no Copy on Write (COW) actually happens. This COW would be useless, as it would immediately get changed to something else. This function also removes any other encumbrances that would be problematic when changing sv.

void  SV_CHECK_THINKFIRST_COW_DROP(SV * sv)

#sv_chop

Efficient removal of characters from the beginning of the string buffer. SvPOK(sv), or at least SvPOKp(sv), must be true and ptr must be a pointer to somewhere inside the string buffer. ptr becomes the first character of the adjusted string. Uses the OOK hack. On return, only SvPOK(sv) and SvPOKp(sv) among the OK flags will be true.

Beware: after this function returns, ptr and SvPVX_const(sv) may no longer refer to the same chunk of data.

The unfortunate similarity of this function's name to that of Perl's chop operator is strictly coincidental. This function works from the left; chop works from the right.

void       sv_chop(      SV * const sv, const char * const ptr)
void  Perl_sv_chop(pTHX_ SV * const sv, const char * const ptr)

#sv_clear

Clear an SV: call any destructors, free up any memory used by the body, and free the body itself. The SV's head is not freed, although its type is set to all 1's so that it won't inadvertently be assumed to be live during global destruction etc. This function should only be called when REFCNT is zero. Most of the time you'll want to call SvREFCNT_dec instead.

void       sv_clear(      SV * const orig_sv)
void  Perl_sv_clear(pTHX_ SV * const orig_sv)

#sv_cmp

#sv_cmp_flags

These each compare the strings in two SVs, returning -1, 0, or 1 indicating whether the string in sv1 is less than, equal to, or greater than the string in sv2. They are UTF-8 and 'use bytes' aware, and will coerce their arguments to strings if necessary.

sv_cmp always handles 'get' magic. sv_cmp_flags only does so if flags contains SV_GMAGIC. Otherwise, the two forms behave identically.

See also "sv_cmp_locale".

I32       sv_cmp      (      SV * const sv1, SV * const sv2)
I32  Perl_sv_cmp      (pTHX_ SV * const sv1, SV * const sv2)
I32       sv_cmp_flags(      SV * const sv1, SV * const sv2,
                             const U32 flags)
I32  Perl_sv_cmp_flags(pTHX_ SV * const sv1, SV * const sv2,
                             const U32 flags)

#sv_cmp_locale

#sv_cmp_locale_flags

These each compare the strings in two SVs in a locale-aware manner, returning -1, 0, or 1 indicating whether the string in sv1 is less than, equal to, or greater than the string in sv2.

They are UTF-8 and 'use bytes' aware, and will coerce their args to strings if necessary.

sv_cmp_locale always handles 'get' magic. sv_cmp_locale_flags only does so if flags contains SV_GMAGIC. Otherwise, the two forms behave identically.

See also "sv_cmp".

I32       sv_cmp_locale      (      SV * const sv1,
                                    SV * const sv2)
I32  Perl_sv_cmp_locale      (pTHX_ SV * const sv1,
                                    SV * const sv2)
I32       sv_cmp_locale_flags(      SV * const sv1,
                                    SV * const sv2,
                                    const U32 flags)
I32  Perl_sv_cmp_locale_flags(pTHX_ SV * const sv1,
                                    SV * const sv2,
                                    const U32 flags)

#sv_collxfrm

#sv_collxfrm_flags

These each add Collate Transform magic to an SV if it doesn't already have it.

Any scalar variable may carry PERL_MAGIC_collxfrm magic that contains the scalar data of the variable, but transformed to such a format that a normal memory comparison can be used to compare the data according to the locale settings.

sv_collxfrm always handles 'get' magic. sv_collxfrm_flags only does so if flags contains SV_GMAGIC. Otherwise, the two forms behave identically.

char *       sv_collxfrm      (      SV * const sv,
                                     STRLEN * const nxp)
char *  Perl_sv_collxfrm      (pTHX_ SV * const sv,
                                     STRLEN * const nxp)
char *       sv_collxfrm_flags(      SV * const sv,
                                     STRLEN * const nxp,
                                     I32 const flags)
char *  Perl_sv_collxfrm_flags(pTHX_ SV * const sv,
                                     STRLEN * const nxp,
                                     I32 const flags)

#sv_copypv

#sv_copypv_flags

#sv_copypv_nomg

These copy a stringified representation of the source SV into the destination SV. They automatically perform coercion of numeric values into strings. Guaranteed to preserve the UTF8 flag even from overloaded objects. Similar in nature to sv_2pv[_flags] but they operate directly on an SV instead of just the string. Mostly they use "sv_2pv_flags" to do the work, except when that would lose the UTF-8'ness of the PV.

The three forms differ only in whether or not they perform 'get magic' on sv. sv_copypv_nomg skips 'get magic'; sv_copypv performs it; and sv_copypv_flags either performs it (if the SV_GMAGIC bit is set in flags) or doesn't (if that bit is cleared).

void       sv_copypv      (      SV * const dsv, SV * const ssv)
void  Perl_sv_copypv      (pTHX_ SV * const dsv, SV * const ssv)
void       sv_copypv_flags(      SV * const dsv, SV * const ssv,
                                 const I32 flags)
void  Perl_sv_copypv_flags(pTHX_ SV * const dsv, SV * const ssv,
                                 const I32 flags)
void       sv_copypv_nomg (      SV * const dsv, SV * const ssv)

#sv_dec

#sv_dec_nomg

These auto-decrement the value in the SV, doing string to numeric conversion if necessary. They both handle operator overloading.

They differ only in that:

sv_dec handles 'get' magic; sv_dec_nomg skips 'get' magic.

void       sv_dec     (      SV * const sv)
void  Perl_sv_dec     (pTHX_ SV * const sv)
void       sv_dec_nomg(      SV * const sv)
void  Perl_sv_dec_nomg(pTHX_ SV * const sv)

#sv_derived_from

#sv_derived_from_hv

#sv_derived_from_pv

#sv_derived_from_pvn

#sv_derived_from_sv

These each return a boolean indicating whether sv is derived from the specified class at the C level. To check derivation at the Perl level, call isa() as a normal Perl method.

In sv_derived_from_hv, the class name is HvNAME(hv) (which would presumably represent a stash). Its UTF8ness is HvNAMEUTF8(hv).

In sv_derived_from and sv_derived_from_pv, the class name is given by name, which is a NUL-terminated C string. In sv_derived_from, the name is never considered to be encoded as UTF-8.

The remaining forms differ only in how the class name is specified; they all have a flags parameter. Currently, the only significant value for which is SVf_UTF8 to indicate that the class name is encoded as such.

In sv_derived_from_sv, the class name is extracted from namesv. This is the preferred form. The class name is considered to be in UTF-8 if namesv is marked as such.

In sv_derived_from_pvn, len gives the length of name, so the latter may contain embedded NUL characters.

bool       sv_derived_from    (      SV *sv,
                                     const char * const name)
bool  Perl_sv_derived_from    (pTHX_ SV *sv,
                                     const char * const name)
bool       sv_derived_from_hv (      SV *sv, HV *hv)
bool  Perl_sv_derived_from_hv (pTHX_ SV *sv, HV *hv)
bool       sv_derived_from_pv (      SV *sv,
                                     const char * const name,
                                     U32 flags)
bool  Perl_sv_derived_from_pv (pTHX_ SV *sv,
                                     const char * const name,
                                     U32 flags)
bool       sv_derived_from_pvn(      SV *sv,
                                     const char * const name,
                                     const STRLEN len, U32 flags)
bool  Perl_sv_derived_from_pvn(pTHX_ SV *sv,
                                     const char * const name,
                                     const STRLEN len, U32 flags)
bool       sv_derived_from_sv (      SV *sv, SV *namesv,
                                     U32 flags)
bool  Perl_sv_derived_from_sv (pTHX_ SV *sv, SV *namesv,
                                     U32 flags)

#sv_does

Like "sv_does_pv", but doesn't take a flags parameter.

bool       sv_does(      SV *sv, const char * const name)
bool  Perl_sv_does(pTHX_ SV *sv, const char * const name)

#sv_does_pv

Like "sv_does_sv", but takes a nul-terminated string instead of an SV.

bool       sv_does_pv(      SV *sv, const char * const name,
                            U32 flags)
bool  Perl_sv_does_pv(pTHX_ SV *sv, const char * const name,
                            U32 flags)

#sv_does_pvn

Like "sv_does_sv", but takes a string/length pair instead of an SV.

bool       sv_does_pvn(      SV *sv, const char * const name,
                             const STRLEN len, U32 flags)
bool  Perl_sv_does_pvn(pTHX_ SV *sv, const char * const name,
                             const STRLEN len, U32 flags)

#sv_does_sv

Returns a boolean indicating whether the SV performs a specific, named role. The SV can be a Perl object or the name of a Perl class.

bool       sv_does_sv(      SV *sv, SV *namesv, U32 flags)
bool  Perl_sv_does_sv(pTHX_ SV *sv, SV *namesv, U32 flags)

#sv_eq

#sv_eq_flags

These each return a boolean indicating whether or not the strings in the two SVs are equal. If 'use bytes' is in effect, the comparison is byte-by-byte; otherwise character-by-character. Each will coerce its args to strings if necessary.

They differ only in that sv_eq always processes get magic, while sv_eq_flags processes get magic only when the flags parameter has the SV_GMAGIC bit set.

These functions do not handle operator overloading. For versions that do, see instead "sv_streq" or "sv_streq_flags".

I32       sv_eq      (      SV *sv1, SV *sv2)
I32  Perl_sv_eq      (pTHX_ SV *sv1, SV *sv2)
I32       sv_eq_flags(      SV *sv1, SV *sv2, const U32 flags)
I32  Perl_sv_eq_flags(pTHX_ SV *sv1, SV *sv2, const U32 flags)

#sv_force_normal

#sv_force_normal_flags

Undo various types of fakery on an SV, where fakery means "more than" a string:

#if the PV is a shared string

make a private copy

#if we're a ref

stop refing. This is done by calling "sv_unref_flags". In sv_force_normal_flags, the flags parameter gets passed to that function.

#if we're a glob

downgrade to an xpvmg;

#if we're a copy-on-write scalar

this is the on-write time when we do the copy, and is also used locally

#if this is a vstring

drop the vstring magic

#in sv_force_normal_flags if SV_COW_DROP_PV is set in flags

a copy-on-write scalar drops its PV buffer (if any) and becomes SvPOK_off rather than making a copy. (Used where this scalar is about to be set to some other value.)

Other than what was mentioned above, the two forms behave identically. This is because sv_force_normal merely calls sv_force_normal_flags with flags set to 0.

void       sv_force_normal      (      SV *sv)
void  Perl_sv_force_normal      (pTHX_ SV *sv)
void       sv_force_normal_flags(      SV * const sv,
                                       const U32 flags)
void  Perl_sv_force_normal_flags(pTHX_ SV * const sv,
                                       const U32 flags)

#sv_free

Decrement an SV's reference count, and if it drops to zero, call sv_clear to invoke destructors and free up any memory used by the body; finally, deallocating the SV's head itself. Normally called via a wrapper macro SvREFCNT_dec.

void       sv_free(      SV * const sv)
void  Perl_sv_free(pTHX_ SV * const sv)

#sv_get_backrefs

NOTE: sv_get_backrefs is experimental and may change or be removed without notice.

If sv is the target of a weak reference then it returns the back references structure associated with the sv; otherwise return NULL.

When returning a non-null result the type of the return is relevant. If it is an AV then the elements of the AV are the weak reference RVs which point at this item. If it is any other type then the item itself is the weak reference.

See also Perl_sv_add_backref(), Perl_sv_del_backref(), Perl_sv_kill_backrefs()

SV *       sv_get_backrefs(SV * const sv)
SV *  Perl_sv_get_backrefs(SV * const sv)

#sv_gets

Get a line from the filehandle and store it into the SV, optionally appending to the currently-stored string. If append is not 0, the line is appended to the SV instead of overwriting it. append should be set to the byte offset that the appended string should start at in the SV (typically, SvCUR(sv) is a suitable choice).

char *       sv_gets(      SV * const sv, PerlIO * const fp,
                           SSize_t append)
char *  Perl_sv_gets(pTHX_ SV * const sv, PerlIO * const fp,
                           SSize_t append)

#sv_inc

#sv_inc_nomg

These auto-increment the value in the SV, doing string to numeric conversion if necessary. They both handle operator overloading.

They differ only in that sv_inc performs 'get' magic; sv_inc_nomg skips any magic.

void       sv_inc     (      SV * const sv)
void  Perl_sv_inc     (pTHX_ SV * const sv)
void       sv_inc_nomg(      SV * const sv)
void  Perl_sv_inc_nomg(pTHX_ SV * const sv)

#sv_insert

#sv_insert_flags

These insert and/or replace a string at the specified offset/length within the SV. Similar to the Perl substr() function, with littlelen bytes starting at little replacing len bytes of the string in bigstr starting at offset. They handle get magic.

sv_insert_flags is identical to plain sv_insert, but the extra flags are passed to the SvPV_force_flags operation that is internally applied to bigstr.

void       sv_insert      (      SV * const bigstr,
                                 const STRLEN offset,
                                 const STRLEN len,
                                 const char * const little,
                                 const STRLEN littlelen)
void  Perl_sv_insert      (pTHX_ SV * const bigstr,
                                 const STRLEN offset,
                                 const STRLEN len,
                                 const char * const little,
                                 const STRLEN littlelen)
void       sv_insert_flags(      SV * const bigstr,
                                 const STRLEN offset,
                                 const STRLEN len,
                                 const char *little,
                                 const STRLEN littlelen,
                                 const U32 flags)
void  Perl_sv_insert_flags(pTHX_ SV * const bigstr,
                                 const STRLEN offset,
                                 const STRLEN len,
                                 const char *little,
                                 const STRLEN littlelen,
                                 const U32 flags)

#sv_isa

Returns a boolean indicating whether the SV is blessed into the specified class.

This does not check for subtypes or method overloading. Use sv_isa_sv to verify an inheritance relationship in the same way as the isa operator by respecting any isa() method overloading; or sv_derived_from_sv to test directly on the actual object type.

int       sv_isa(      SV *sv, const char * const name)
int  Perl_sv_isa(pTHX_ SV *sv, const char * const name)

#sv_isa_sv

Returns a boolean indicating whether the SV is an object reference and is derived from the specified class, respecting any isa() method overloading it may have. Returns false if sv is not a reference to an object, or is not derived from the specified class.

This is the function used to implement the behaviour of the isa operator.

Does not invoke magic on sv.

Not to be confused with the older sv_isa function, which does not use an overloaded isa() method, nor will check subclassing.

bool       sv_isa_sv(      SV *sv, SV *namesv)
bool  Perl_sv_isa_sv(pTHX_ SV *sv, SV *namesv)

#sv_isobject

Returns a boolean indicating whether the SV is an RV pointing to a blessed object. If the SV is not an RV, or if the object is not blessed, then this will return false.

int       sv_isobject(      SV *sv)
int  Perl_sv_isobject(pTHX_ SV *sv)

#sv_len

Returns the length of the string in the SV. Handles magic and type coercion and sets the UTF8 flag appropriately. See also "SvCUR", which gives raw access to the xpv_cur slot.

STRLEN       sv_len(      SV * const sv)
STRLEN  Perl_sv_len(pTHX_ SV * const sv)

#sv_len_utf8

#sv_len_utf8_nomg

These return the number of characters in the string in an SV, counting wide UTF-8 bytes as a single character. Both handle type coercion. They differ only in that sv_len_utf8 performs 'get' magic; sv_len_utf8_nomg skips any magic.

STRLEN       sv_len_utf8     (      SV * const sv)
STRLEN  Perl_sv_len_utf8     (pTHX_ SV * const sv)
STRLEN       sv_len_utf8_nomg(      SV * const sv)
STRLEN  Perl_sv_len_utf8_nomg(pTHX_ SV * const sv)

#sv_magic

Adds magic to an SV. First upgrades sv to type SVt_PVMG if necessary, then adds a new magic item of type how to the head of the magic list.

See "sv_magicext" (which sv_magic now calls) for a description of the handling of the name and namlen arguments.

You need to use sv_magicext to add magic to SvREADONLY SVs and also to add more than one instance of the same how.

void       sv_magic(      SV * const sv, SV * const obj,
                          const int how, const char * const name,
                          const I32 namlen)
void  Perl_sv_magic(pTHX_ SV * const sv, SV * const obj,
                          const int how, const char * const name,
                          const I32 namlen)

#sv_magicext

Adds magic to an SV, upgrading it if necessary. Applies the supplied vtable and returns a pointer to the magic added.

Note that sv_magicext will allow things that sv_magic will not. In particular, you can add magic to SvREADONLY SVs, and add more than one instance of the same how.

If namlen is greater than zero then a savepvn copy of name is stored, if namlen is zero then name is stored as-is and - as another special case - if (name && namlen == HEf_SVKEY) then name is assumed to contain an SV* and is stored as-is with its REFCNT incremented.

(This is now used as a subroutine by sv_magic.)

MAGIC *       sv_magicext(      SV * const sv, SV * const obj,
                                const int how,
                                const MGVTBL * const vtbl,
                                const char * const name,
                                const I32 namlen)
MAGIC *  Perl_sv_magicext(pTHX_ SV * const sv, SV * const obj,
                                const int how,
                                const MGVTBL * const vtbl,
                                const char * const name,
                                const I32 namlen)

#sv_mortalcopy

#sv_mortalcopy_flags

These each create a new SV which is a copy of the original SV (using "sv_setsv"). The new SV is marked as mortal. It will be destroyed "soon", either by an explicit call to FREETMPS, or by an implicit call at places such as statement boundaries. See also "sv_newmortal" and "sv_2mortal".

The two forms are identical, except sv_mortalcopy_flags has an extra flags parameter, the contents of which are passed along to "sv_setsv_flags".

SV *       sv_mortalcopy      (      SV * const oldsv)
SV *  Perl_sv_mortalcopy      (pTHX_ SV * const oldsv)
SV *       sv_mortalcopy_flags(      SV * const oldsv, U32 flags)
SV *  Perl_sv_mortalcopy_flags(pTHX_ SV * const oldsv, U32 flags)

#sv_newmortal

Creates a new null SV which is mortal. The reference count of the SV is set to 1. It will be destroyed "soon", either by an explicit call to FREETMPS, or by an implicit call at places such as statement boundaries. See also "sv_mortalcopy" and "sv_2mortal".

SV *       sv_newmortal()
SV *  Perl_sv_newmortal(pTHX)

#sv_nolocking

DEPRECATED! It is planned to remove sv_nolocking from a future release of Perl. Do not use it for new code; remove it from existing code.

Dummy routine which "locks" an SV when there is no locking module present. Exists to avoid test for a NULL function pointer and because it could potentially warn under some level of strict-ness.

"Superseded" by sv_nosharing().

void       sv_nolocking(      SV *sv)
void  Perl_sv_nolocking(pTHX_ SV *sv)

#sv_nounlocking

DEPRECATED! It is planned to remove sv_nounlocking from a future release of Perl. Do not use it for new code; remove it from existing code.

Dummy routine which "unlocks" an SV when there is no locking module present. Exists to avoid test for a NULL function pointer and because it could potentially warn under some level of strict-ness.

"Superseded" by sv_nosharing().

void       sv_nounlocking(      SV *sv)
void  Perl_sv_nounlocking(pTHX_ SV *sv)

#sv_numeq

#sv_numeq_flags

These each return a boolean indicating whether the numbers in the two SV arguments are identical. Those arguments will be coerced to numbers if necessary. A NULL SV is treated as undef.

In sv_numeq_flags, if flags has the SV_GMAGIC bit set, 'get' magic is handled.

And unless flags has the SV_SKIP_OVERLOAD bit set, an attempt to use == overloading will be made. If such overloading does not exist or the flag is set, then regular numerical comparison will be used instead.

sv_numeq merely calls sv_numeq_flags with just the SV_GMAGIC bit set. This function basically behaves like the Perl code $sv1 == $sv2.

bool       sv_numeq      (      SV *sv1, SV *sv2)
bool       sv_numeq_flags(      SV *sv1, SV *sv2,
                                const U32 flags)
bool  Perl_sv_numeq_flags(pTHX_ SV *sv1, SV *sv2,
                                const U32 flags)

#sv_pos_b2u

#sv_pos_b2u_flags

These each count the number of UTF-8 encoded characters in the PV of sv. The entire PV is not necessarily looked at, just the first so-many bytes. The byte count is given by *offsetp in sv_pos_b2u, and by offset in sv_pos_b2u_flags.

The caller must ensure that the PV contains at least as many bytes as the count passed in.

sv_pos_b2u returns void, instead updating *offsetp to the character count. sv_pos_b2u_flags returns the character count.

sv_pos_b2u_flags is preferred as offsetp is a *I32, which limits the size it can handle to 2Gb.

Both handle type coercion.

sv_pos_b2u always handles 'get' magic. sv_pos_b2u_flags only handles 'get' magic when flags contains SV_GMAGIC.

In fact, sv_pos_b2u_flags passes flags to SvPV_flags, and flags usually should be SV_GMAGIC|SV_CONST_RETURN. sv_pos_b2u automatically causes SV_CONST_RETURN to be passed to SvPV_flags.

Both functions use and update PERL_MAGIC_utf8.

void         sv_pos_b2u      (      SV * const sv,
                                    I32 * const offsetp)
void    Perl_sv_pos_b2u      (pTHX_ SV * const sv,
                                    I32 * const offsetp)
STRLEN       sv_pos_b2u_flags(      SV * const sv,
                                    STRLEN const offset,
                                    U32 flags)
STRLEN  Perl_sv_pos_b2u_flags(pTHX_ SV * const sv,
                                    STRLEN const offset,
                                    U32 flags)

#sv_pos_u2b

#sv_pos_u2b_flags

These each find out how many bytes are occupied by the first so-many UTF-8-encoded characters in the PV of sv. The character count is passed by *offsetp in sv_pos_u2b, and by uoffset in sv_pos_u2b_flags.

Optionally, they also count how many bytes are in the next so-many UTF-8-encoded characters. This option is chosen in both functions by passing a non-NULL lenp to them, and setting *lenp to the desired character count. The functions update *lenp with the byte count.

sv_pos_u2b returns void, instead updating *offsetp to the byte count. sv_pos_u2b_flags returns the byte count.

sv_pos_u2b_flags is preferred as offsetp is a *I32, which limits the size it can handle to 2Gb.

Both handle type coercion.

sv_pos_u2b always handles 'get' magic. sv_pos_u2b_flags only handles 'get' magic when flags contains SV_GMAGIC.

In fact, sv_pos_u2b_flags passes flags to SvPV_flags, and flags usually should be SV_GMAGIC|SV_CONST_RETURN. sv_pos_u2b automatically causes SV_CONST_RETURN to be passed to SvPV_flags.

Both functions use and update PERL_MAGIC_utf8.

void         sv_pos_u2b      (      SV * const sv,
                                    I32 * const offsetp,
                                    I32 * const lenp)
void    Perl_sv_pos_u2b      (pTHX_ SV * const sv,
                                    I32 * const offsetp,
                                    I32 * const lenp)
STRLEN       sv_pos_u2b_flags(      SV * const sv,
                                    STRLEN uoffset,
                                    STRLEN * const lenp,
                                    U32 flags)
STRLEN  Perl_sv_pos_u2b_flags(pTHX_ SV * const sv,
                                    STRLEN uoffset,
                                    STRLEN * const lenp,
                                    U32 flags)

#sv_pvn_force_flags

Get a sensible string out of the SV somehow. If flags has the SV_GMAGIC bit set, will "mg_get" on sv if appropriate, else not. sv_pvn_force and sv_pvn_force_nomg are implemented in terms of this function. You normally want to use the various wrapper macros instead: see "SvPV_force" and "SvPV_force_nomg".

char *       sv_pvn_force_flags(      SV * const sv,
                                      STRLEN * const lp,
                                      const U32 flags)
char *  Perl_sv_pvn_force_flags(pTHX_ SV * const sv,
                                      STRLEN * const lp,
                                      const U32 flags)

#sv_ref

Returns a SV describing what the SV passed in is a reference to.

dst can be a SV to be set to the description or NULL, in which case a mortal SV is returned.

If ob is true and the SV is blessed, the description is the class name, otherwise it is the type of the SV, "SCALAR", "ARRAY" etc.

SV *       sv_ref(      SV *dst, const SV * const sv,
                        const int ob)
SV *  Perl_sv_ref(pTHX_ SV *dst, const SV * const sv,
                        const int ob)

#sv_reftype

Returns a string describing what the SV is a reference to.

If ob is true and the SV is blessed, the string is the class name, otherwise it is the type of the SV, "SCALAR", "ARRAY" etc.

const char *       sv_reftype(      const SV * const sv,
                                    const int ob)
const char *  Perl_sv_reftype(pTHX_ const SV * const sv,
                                    const int ob)

#sv_replace

Make the first argument a copy of the second, then delete the original. The target SV physically takes over ownership of the body of the source SV and inherits its flags; however, the target keeps any magic it owns, and any magic in the source is discarded. Note that this is a rather specialist SV copying operation; most of the time you'll want to use sv_setsv or one of its many macro front-ends.

void       sv_replace(      SV * const sv, SV * const nsv)
void  Perl_sv_replace(pTHX_ SV * const sv, SV * const nsv)

#sv_report_used

Dump the contents of all SVs not yet freed (debugging aid).

void       sv_report_used()
void  Perl_sv_report_used(pTHX)

#sv_reset

Underlying implementation for the reset Perl function. Note that the perl-level function is vaguely deprecated.

void       sv_reset(      const char *s, HV * const stash)
void  Perl_sv_reset(pTHX_ const char *s, HV * const stash)

#sv_rvunweaken

Unweaken a reference: Clear the SvWEAKREF flag on this RV; remove the backreference to this RV from the array of backreferences associated with the target SV, increment the refcount of the target. Silently ignores undef and warns on non-weak references.

SV *       sv_rvunweaken(      SV * const sv)
SV *  Perl_sv_rvunweaken(pTHX_ SV * const sv)

#sv_rvweaken

Weaken a reference: set the SvWEAKREF flag on this RV; give the referred-to SV PERL_MAGIC_backref magic if it hasn't already; and push a back-reference to this RV onto the array of backreferences associated with that magic. If the RV is magical, set magic will be called after the RV is cleared. Silently ignores undef and warns on already-weak references.

SV *       sv_rvweaken(      SV * const sv)
SV *  Perl_sv_rvweaken(pTHX_ SV * const sv)

#sv_set_bool

Equivalent to sv_setsv(sv, bool_val ? &Pl_sv_yes : &PL_sv_no), but may be made more efficient in the future. Doesn't handle set magic.

The perl equivalent is $sv = !!$expr;.

Introduced in perl 5.35.11.

void       sv_set_bool(      SV *sv, const bool bool_val)
void  Perl_sv_set_bool(pTHX_ SV *sv, const bool bool_val)

#sv_set_false

Equivalent to sv_setsv(sv, &PL_sv_no), but may be made more efficient in the future. Doesn't handle set magic.

The perl equivalent is $sv = !1;.

Introduced in perl 5.35.11.

void       sv_set_false(      SV *sv)
void  Perl_sv_set_false(pTHX_ SV *sv)

#sv_set_true

Equivalent to sv_setsv(sv, &PL_sv_yes), but may be made more efficient in the future. Doesn't handle set magic.

The perl equivalent is $sv = !0;.

Introduced in perl 5.35.11.

void       sv_set_true(      SV *sv)
void  Perl_sv_set_true(pTHX_ SV *sv)

#sv_set_undef

Equivalent to sv_setsv(sv, &PL_sv_undef), but more efficient. Doesn't handle set magic.

The perl equivalent is $sv = undef;. Note that it doesn't free any string buffer, unlike undef $sv.

Introduced in perl 5.25.12.

void       sv_set_undef(      SV *sv)
void  Perl_sv_set_undef(pTHX_ SV *sv)

#sv_setbool

#sv_setbool_mg

These set an SV to a true or false boolean value, upgrading first if necessary.

They differ only in that sv_setbool_mg handles 'set' magic; sv_setbool does not.

void  sv_setbool   (SV *sv, bool b)
void  sv_setbool_mg(SV *sv, bool b)

#sv_setiv

#sv_setiv_mg

These copy an integer into the given SV, upgrading first if necessary.

They differ only in that sv_setiv_mg handles 'set' magic; sv_setiv does not.

void       sv_setiv   (      SV * const sv, const IV num)
void  Perl_sv_setiv   (pTHX_ SV * const sv, const IV num)
void       sv_setiv_mg(      SV * const sv, const IV i)
void  Perl_sv_setiv_mg(pTHX_ SV * const sv, const IV i)

#sv_setnv

#sv_setnv_mg

These copy a double into the given SV, upgrading first if necessary.

They differ only in that sv_setnv_mg handles 'set' magic; sv_setnv does not.

void       sv_setnv   (      SV * const sv, const NV num)
void  Perl_sv_setnv   (pTHX_ SV * const sv, const NV num)
void       sv_setnv_mg(      SV * const sv, const NV num)
void  Perl_sv_setnv_mg(pTHX_ SV * const sv, const NV num)

#sv_setpv

#sv_setpv_mg

#sv_setpvn

#sv_setpvn_fresh

#sv_setpvn_mg

#sv_setpvs

#sv_setpvs_mg

These copy a string into the SV sv, making sure it is "SvPOK_only".

In the pvs forms, the string must be a C literal string, enclosed in double quotes.

In the pvn forms, the first byte of the string is pointed to by ptr, and len indicates the number of bytes to be copied, potentially including embedded NUL characters.

In the plain pv forms, ptr points to a NUL-terminated C string. That is, it points to the first byte of the string, and the copy proceeds up through the first encountered NUL byte.

In the forms that take a ptr argument, if it is NULL, the SV will become undefined.

The UTF-8 flag is not changed by these functions.

A terminating NUL byte is guaranteed in the result.

The _mg forms handle 'set' magic; the other forms skip all magic.

sv_setpvn_fresh is a cut-down alternative to sv_setpvn, intended ONLY to be used with a fresh sv that has been upgraded to a SVt_PV, SVt_PVIV, SVt_PVNV, or SVt_PVMG.

void       sv_setpv       (      SV * const sv,
                                 const char * const ptr)
void  Perl_sv_setpv       (pTHX_ SV * const sv,
                                 const char * const ptr)
void       sv_setpv_mg    (      SV * const sv,
                                 const char * const ptr)
void  Perl_sv_setpv_mg    (pTHX_ SV * const sv,
                                 const char * const ptr)
void       sv_setpvn      (      SV * const sv,
                                 const char * const ptr,
                                 const STRLEN len)
void  Perl_sv_setpvn      (pTHX_ SV * const sv,
                                 const char * const ptr,
                                 const STRLEN len)
void       sv_setpvn_fresh(      SV * const sv,
                                 const char * const ptr,
                                 const STRLEN len)
void  Perl_sv_setpvn_fresh(pTHX_ SV * const sv,
                                 const char * const ptr,
                                 const STRLEN len)
void       sv_setpvn_mg   (      SV * const sv,
                                 const char * const ptr,
                                 const STRLEN len)
void  Perl_sv_setpvn_mg   (pTHX_ SV * const sv,
                                 const char * const ptr,
                                 const STRLEN len)
void       sv_setpvs      (      SV *const sv, "literal string")
void       sv_setpvs_mg   (      SV *const sv, "literal string")

#sv_setpv_bufsize

Sets the SV to be a string of cur bytes length, with at least len bytes available. Ensures that there is a null byte at SvEND.

Returns a char * pointer to the SvPV buffer.

The caller must set the first cur bytes of sv before the first use of its contents. This means that if cur is zero, the SV is immediately fully formed and ready to use, just like any other SV containing an empty string.

char  *       sv_setpv_bufsize(      SV * const sv,
                                     const STRLEN cur,
                                     const STRLEN len)
char  *  Perl_sv_setpv_bufsize(pTHX_ SV * const sv,
                                     const STRLEN cur,
                                     const STRLEN len)

#sv_setpv_mg*

Described under "sv_setpv"

#sv_setpvf

#sv_setpvf_mg

#sv_setpvf_mg_nocontext

#sv_setpvf_nocontext

These work like "sv_catpvf" but copy the text into the SV instead of appending it.

The differences between these are:

sv_setpvf_mg and sv_setpvf_mg_nocontext perform 'set' magic; sv_setpvf and sv_setpvf_nocontext skip all magic.

sv_setpvf_nocontext and sv_setpvf_mg_nocontext do not take a thread context (aTHX) parameter, so are used in situations where the caller doesn't already have the thread context.

The UTF-8 flag is not changed by these functions.

void  Perl_sv_setpvf             (pTHX_ SV * const sv,
                                        const char * const pat,
                                        ...)
void  Perl_sv_setpvf_mg          (pTHX_ SV * const sv,
                                        const char * const pat,
                                        ...)
void       sv_setpvf_mg_nocontext(      SV * const sv,
                                        const char * const pat,
                                        ...)
void  Perl_sv_setpvf_mg_nocontext(      SV * const sv,
                                        const char * const pat,
                                        ...)
void       sv_setpvf_nocontext   (      SV * const sv,
                                        const char * const pat,
                                        ...)
void  Perl_sv_setpvf_nocontext   (      SV * const sv,
                                        const char * const pat,
                                        ...)

#sv_setpvn*

#sv_setpvn_fresh*

#sv_setpvn_mg*

#sv_setpvs*

#sv_setpvs_mg*

Described under "sv_setpv"

#sv_setref_iv

Copies an integer into a new SV, optionally blessing the SV. The rv argument will be upgraded to an RV. That RV will be modified to point to the new SV. The classname argument indicates the package for the blessing. Set classname to NULL to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.

SV *       sv_setref_iv(      SV * const rv,
                              const char * const classname,
                              const IV iv)
SV *  Perl_sv_setref_iv(pTHX_ SV * const rv,
                              const char * const classname,
                              const IV iv)

#sv_setref_nv

Copies a double into a new SV, optionally blessing the SV. The rv argument will be upgraded to an RV. That RV will be modified to point to the new SV. The classname argument indicates the package for the blessing. Set classname to NULL to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.

SV *       sv_setref_nv(      SV * const rv,
                              const char * const classname,
                              const NV nv)
SV *  Perl_sv_setref_nv(pTHX_ SV * const rv,
                              const char * const classname,
                              const NV nv)

#sv_setref_pv

Copies a pointer into a new SV, optionally blessing the SV. The rv argument will be upgraded to an RV. That RV will be modified to point to the new SV. If the pv argument is NULL, then PL_sv_undef will be placed into the SV. The classname argument indicates the package for the blessing. Set classname to NULL to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.

Do not use with other Perl types such as HV, AV, SV, CV, because those objects will become corrupted by the pointer copy process.

Note that sv_setref_pvn copies the string while this copies the pointer.

SV *       sv_setref_pv(      SV * const rv,
                              const char * const classname,
                              void * const pv)
SV *  Perl_sv_setref_pv(pTHX_ SV * const rv,
                              const char * const classname,
                              void * const pv)

#sv_setref_pvn

Copies a string into a new SV, optionally blessing the SV. The length of the string must be specified with n. The rv argument will be upgraded to an RV. That RV will be modified to point to the new SV. The classname argument indicates the package for the blessing. Set classname to NULL to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.

Note that sv_setref_pv copies the pointer while this copies the string.

SV *       sv_setref_pvn(      SV * const rv,
                               const char * const classname,
                               const char * const pv,
                               const STRLEN n)
SV *  Perl_sv_setref_pvn(pTHX_ SV * const rv,
                               const char * const classname,
                               const char * const pv,
                               const STRLEN n)

#sv_setref_pvs

Like sv_setref_pvn, but takes a literal string instead of a string/length pair.

SV *  sv_setref_pvs(SV *const rv, const char *const classname,
                    "literal string")

#sv_setref_uv

Copies an unsigned integer into a new SV, optionally blessing the SV. The rv argument will be upgraded to an RV. That RV will be modified to point to the new SV. The classname argument indicates the package for the blessing. Set classname to NULL to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.

SV *       sv_setref_uv(      SV * const rv,
                              const char * const classname,
                              const UV uv)
SV *  Perl_sv_setref_uv(pTHX_ SV * const rv,
                              const char * const classname,
                              const UV uv)

#sv_setrv_inc

#sv_setrv_inc_mg

As sv_setrv_noinc but increments the reference count of ref.

sv_setrv_inc_mg will invoke 'set' magic on the SV; sv_setrv_inc will not.

void       sv_setrv_inc   (      SV * const sv, SV * const ref)
void  Perl_sv_setrv_inc   (pTHX_ SV * const sv, SV * const ref)
void       sv_setrv_inc_mg(      SV * const sv, SV * const ref)
void  Perl_sv_setrv_inc_mg(pTHX_ SV * const sv, SV * const ref)

#sv_setrv_noinc

#sv_setrv_noinc_mg

Copies an SV pointer into the given SV as an SV reference, upgrading it if necessary. After this, SvRV(sv) is equal to ref. This does not adjust the reference count of ref. The reference ref must not be NULL.

sv_setrv_noinc_mg will invoke 'set' magic on the SV; sv_setrv_noinc will not.

void       sv_setrv_noinc   (      SV * const sv, SV * const ref)
void  Perl_sv_setrv_noinc   (pTHX_ SV * const sv, SV * const ref)
void       sv_setrv_noinc_mg(      SV * const sv, SV * const ref)
void  Perl_sv_setrv_noinc_mg(pTHX_ SV * const sv, SV * const ref)

#sv_setsv

#sv_setsv_flags

#sv_setsv_mg

#sv_setsv_nomg

These copy the contents of the source SV ssv into the destination SV dsv. ssv may be destroyed if it is mortal, so don't use these functions if the source SV needs to be reused. Loosely speaking, they perform a copy-by-value, obliterating any previous content of the destination.

They differ only in that:

sv_setsv calls 'get' magic on ssv, but skips 'set' magic on dsv.

sv_setsv_mg calls both 'get' magic on ssv and 'set' magic on dsv.

sv_setsv_nomg skips all magic.

sv_setsv_flags has a flags parameter which you can use to specify any combination of magic handling, and also you can specify SV_NOSTEAL so that the buffers of temps will not be stolen.

You probably want to instead use one of the assortment of wrappers, such as "SvSetSV", "SvSetSV_nosteal", "SvSetMagicSV" and "SvSetMagicSV_nosteal".

sv_setsv_flags is the primary function for copying scalars, and most other copy-ish functions and macros use it underneath.

void       sv_setsv      (      SV *dsv, SV *ssv)
void  Perl_sv_setsv      (pTHX_ SV *dsv, SV *ssv)
void       sv_setsv_flags(      SV *dsv, SV *ssv,
                                const I32 flags)
void  Perl_sv_setsv_flags(pTHX_ SV *dsv, SV *ssv,
                                const I32 flags)
void       sv_setsv_mg   (      SV * const dsv, SV * const ssv)
void  Perl_sv_setsv_mg   (pTHX_ SV * const dsv, SV * const ssv)
void       sv_setsv_nomg (      SV *dsv, SV *ssv)

#sv_setuv

#sv_setuv_mg

These copy an unsigned integer into the given SV, upgrading first if necessary.

They differ only in that sv_setuv_mg handles 'set' magic; sv_setuv does not.

void       sv_setuv   (      SV * const sv, const UV num)
void  Perl_sv_setuv   (pTHX_ SV * const sv, const UV num)
void       sv_setuv_mg(      SV * const sv, const UV u)
void  Perl_sv_setuv_mg(pTHX_ SV * const sv, const UV u)

#sv_streq

#sv_streq_flags

These each return a boolean indicating whether the strings in the two SVs are identical.

sv_streq_flags is the more general form, having a flags argument that affects its behavior in two ways. It coerces its args to strings if necessary, treating a NULL argument as undef. It correctly handles the UTF8 flag.

If flags has the SV_GMAGIC bit set, 'get' magic will be handled.

If flags does not have the SV_SKIP_OVERLOAD bit set, an attempt to use eq overloading will be made. If such overloading does not exist or the flag is set, then regular string comparison will be used instead.

sv_streq merely calls sv_streq_flags with flags set to just SV_GMAGIC. This function basically behaves like the Perl code $sv1 eq $sv2.

bool       sv_streq      (      SV *sv1, SV *sv2)
bool       sv_streq_flags(      SV *sv1, SV *sv2,
                                const U32 flags)
bool  Perl_sv_streq_flags(pTHX_ SV *sv1, SV *sv2,
                                const U32 flags)

#sv_unmagic

Removes all magic of type type from an SV.

int       sv_unmagic(      SV * const sv, const int type)
int  Perl_sv_unmagic(pTHX_ SV * const sv, const int type)

#sv_unmagicext

Removes all magic of type type with the specified vtbl from an SV.

int       sv_unmagicext(      SV * const sv, const int type,
                              const MGVTBL *vtbl)
int  Perl_sv_unmagicext(pTHX_ SV * const sv, const int type,
                              const MGVTBL *vtbl)

#sv_unref

#sv_unref_flags

These each unset the RV status of the SV, and decrement the reference count of whatever was being referenced by the RV. This can almost be thought of as a reversal of "newSVrv".

sv_unref_flags has an extra parameter, flags, which can contain the SV_IMMEDIATE_UNREF bit to force the reference count to be decremented no matter what.

When that bit isn't set, or with plain sv_unref always, the reference count will not be immediately decremented if the count is 1. Instead, it will be scheduled to be freed at a time of perl's choosing.

Other than the ability to force immediate action, the two forms behave identically.

See "SvROK_off".

void       sv_unref      (      SV *sv)
void  Perl_sv_unref      (pTHX_ SV *sv)
void       sv_unref_flags(      SV * const ref, const U32 flags)
void  Perl_sv_unref_flags(pTHX_ SV * const ref, const U32 flags)

#sv_upgrade

Upgrade an SV to a more complex form. Generally adds a new body type to the SV, then copies across as much information as possible from the old body. It croaks if the SV is already in a more complex form than requested. You generally want to use the SvUPGRADE macro wrapper, which checks the type before calling sv_upgrade, and hence does not croak. See also "svtype".

void       sv_upgrade(      SV * const sv, svtype new_type)
void  Perl_sv_upgrade(pTHX_ SV * const sv, svtype new_type)

#sv_usepvn

#sv_usepvn_flags

#sv_usepvn_mg

These tell an SV to use ptr for its string value. Normally SVs have their string stored inside the SV, but these tell the SV to use an external string instead.

ptr should point to memory that was allocated by "Newx". It must be the start of a Newx-ed block of memory, and not a pointer to the middle of it (beware of OOK and copy-on-write), and not be from a non-Newx memory allocator like malloc. The string length, len, must be supplied. By default this function will "Renew" (i.e. realloc, move) the memory pointed to by ptr, so that the pointer should not be freed or used by the programmer after giving it to sv_usepvn, and neither should any pointers from "behind" that pointer (e.g., ptr + 1) be used.

In the sv_usepvn_flags form, if flags & SV_SMAGIC is true, SvSETMAGIC is called before returning. And if flags & SV_HAS_TRAILING_NUL is true, then ptr[len] must be NUL, and the realloc will be skipped (i.e., the buffer is actually at least 1 byte longer than len, and already meets the requirements for storing in SvPVX).

sv_usepvn is merely sv_usepvn_flags with flags set to 0, so 'set' magic is skipped.

sv_usepvn_mg is merely sv_usepvn_flags with flags set to SV_SMAGIC, so 'set' magic is performed.

void       sv_usepvn      (      SV *sv, char *ptr, STRLEN len)
void  Perl_sv_usepvn      (pTHX_ SV *sv, char *ptr, STRLEN len)
void       sv_usepvn_flags(      SV * const sv, char *ptr,
                                 const STRLEN len,
                                 const U32 flags)
void  Perl_sv_usepvn_flags(pTHX_ SV * const sv, char *ptr,
                                 const STRLEN len,
                                 const U32 flags)
void       sv_usepvn_mg   (      SV *sv, char *ptr, STRLEN len)
void  Perl_sv_usepvn_mg   (pTHX_ SV *sv, char *ptr, STRLEN len)

#sv_utf8_decode

If the PV of the SV is an octet sequence in Perl's extended UTF-8 and contains a multiple-byte character, the SvUTF8 flag is turned on so that it looks like a character. If the PV contains only single-byte characters, the SvUTF8 flag stays off. Scans PV for validity and returns FALSE if the PV is invalid UTF-8.

bool       sv_utf8_decode(      SV * const sv)
bool  Perl_sv_utf8_decode(pTHX_ SV * const sv)

#sv_utf8_downgrade

#sv_utf8_downgrade_flags

#sv_utf8_downgrade_nomg

These attempt to convert the PV of an SV from characters to bytes. If the PV contains a character that cannot fit in a byte, this conversion will fail; in this case, FALSE is returned if fail_ok is true; otherwise they croak.

They are not a general purpose Unicode to byte encoding interface: use the Encode extension for that.

They differ only in that:

sv_utf8_downgrade processes 'get' magic on sv.

sv_utf8_downgrade_nomg does not.

sv_utf8_downgrade_flags has an additional flags parameter in which you can specify SV_GMAGIC to process 'get' magic, or leave it cleared to not process 'get' magic.

bool       sv_utf8_downgrade      (      SV * const sv,
                                         const bool fail_ok)
bool  Perl_sv_utf8_downgrade      (pTHX_ SV * const sv,
                                         const bool fail_ok)
bool       sv_utf8_downgrade_flags(      SV * const sv,
                                         const bool fail_ok,
                                         const U32 flags)
bool  Perl_sv_utf8_downgrade_flags(pTHX_ SV * const sv,
                                         const bool fail_ok,
                                         const U32 flags)
bool       sv_utf8_downgrade_nomg (      SV * const sv,
                                         const bool fail_ok)

#sv_utf8_encode

Converts the PV of an SV to UTF-8, but then turns the SvUTF8 flag off so that it looks like octets again.

void       sv_utf8_encode(      SV * const sv)
void  Perl_sv_utf8_encode(pTHX_ SV * const sv)

#sv_utf8_upgrade

#sv_utf8_upgrade_flags

#sv_utf8_upgrade_flags_grow

#sv_utf8_upgrade_nomg

These convert the PV of an SV to its UTF-8-encoded form. The SV is forced to string form if it is not already. They always set the SvUTF8 flag to avoid future validity checks even if the whole string is the same in UTF-8 as not. They return the number of bytes in the converted string

The forms differ in just two ways. The main difference is whether or not they perform 'get magic' on sv. sv_utf8_upgrade_nomg skips 'get magic'; sv_utf8_upgrade performs it; and sv_utf8_upgrade_flags and sv_utf8_upgrade_flags_grow either perform it (if the SV_GMAGIC bit is set in flags) or don't (if that bit is cleared).

The other difference is that sv_utf8_upgrade_flags_grow has an additional parameter, extra, which allows the caller to specify an amount of space to be reserved as spare beyond what is needed for the actual conversion. This is used when the caller knows it will soon be needing yet more space, and it is more efficient to request space from the system in a single call. This form is otherwise identical to sv_utf8_upgrade_flags.

These are not a general purpose byte encoding to Unicode interface: use the Encode extension for that.

The SV_FORCE_UTF8_UPGRADE flag is now ignored.

STRLEN       sv_utf8_upgrade           (      SV *sv)
STRLEN  Perl_sv_utf8_upgrade           (pTHX_ SV *sv)
STRLEN       sv_utf8_upgrade_flags     (      SV * const sv,
                                              const I32 flags)
STRLEN       sv_utf8_upgrade_flags_grow(      SV * const sv,
                                              const I32 flags,
                                              STRLEN extra)
STRLEN  Perl_sv_utf8_upgrade_flags_grow(pTHX_ SV * const sv,
                                              const I32 flags,
                                              STRLEN extra)
STRLEN       sv_utf8_upgrade_nomg      (      SV *sv)

#sv_vcatpvf*

#sv_vcatpvf_mg*

#sv_vcatpvfn*

#sv_vcatpvfn_flags*

Described under "sv_catpvf"

#sv_vsetpvf

#sv_vsetpvf_mg

These work like "sv_vcatpvf" but copy the text into the SV instead of appending it.

They differ only in that sv_vsetpvf_mg performs 'set' magic; sv_vsetpvf skips all magic.

They are usually used via their frontends, "sv_setpvf" and "sv_setpvf_mg".

The UTF-8 flag is not changed by these functions.

void       sv_vsetpvf   (      SV * const sv,
                               const char * const pat,
                               va_list * const args)
void  Perl_sv_vsetpvf   (pTHX_ SV * const sv,
                               const char * const pat,
                               va_list * const args)
void       sv_vsetpvf_mg(      SV * const sv,
                               const char * const pat,
                               va_list * const args)
void  Perl_sv_vsetpvf_mg(pTHX_ SV * const sv,
                               const char * const pat,
                               va_list * const args)

#sv_vsetpvfn

Works like sv_vcatpvfn but copies the text into the SV instead of appending it.

The UTF-8 flag is not changed by this function.

Usually used via one of its frontends "sv_vsetpvf" and "sv_vsetpvf_mg".

void       sv_vsetpvfn(      SV * const sv,
                             const char * const pat,
                             const STRLEN patlen,
                             va_list * const args,
                             SV ** const svargs,
                             const Size_t sv_count,
                             bool * const maybe_tainted)
void  Perl_sv_vsetpvfn(pTHX_ SV * const sv,
                             const char * const pat,
                             const STRLEN patlen,
                             va_list * const args,
                             SV ** const svargs,
                             const Size_t sv_count,
                             bool * const maybe_tainted)

#sv_2cv

Using various gambits, try to get a CV from an SV; in addition, try if possible to set *st and *gvp to the stash and GV associated with it. The flags in lref are passed to gv_fetchsv.

CV *       sv_2cv(      SV *sv, HV ** const st, GV ** const gvp,
                        const I32 lref)
CV *  Perl_sv_2cv(pTHX_ SV *sv, HV ** const st, GV ** const gvp,
                        const I32 lref)

#sv_2io

Using various gambits, try to get an IO from an SV: the IO slot if its a GV; or the recursive result if we're an RV; or the IO slot of the symbol named after the PV if we're a string.

'Get' magic is ignored on the sv passed in, but will be called on SvRV(sv) if sv is an RV.

IO *       sv_2io(      SV * const sv)
IO *  Perl_sv_2io(pTHX_ SV * const sv)

#sv_2iv_flags

Return the integer value of an SV, doing any necessary string conversion. If flags has the SV_GMAGIC bit set, does an mg_get() first. Normally used via the SvIV(sv) and SvIVx(sv) macros.

IV       sv_2iv_flags(      SV * const sv, const I32 flags)
IV  Perl_sv_2iv_flags(pTHX_ SV * const sv, const I32 flags)

#sv_2mortal

Marks an existing SV as mortal. The SV will be destroyed "soon", either by an explicit call to FREETMPS, or by an implicit call at places such as statement boundaries. SvTEMP() is turned on which means that the SV's string buffer can be "stolen" if this SV is copied. See also "sv_newmortal" and "sv_mortalcopy".

SV *       sv_2mortal(      SV * const sv)
SV *  Perl_sv_2mortal(pTHX_ SV * const sv)

#sv_2nv_flags

Return the num value of an SV, doing any necessary string or integer conversion. If flags has the SV_GMAGIC bit set, does an mg_get() first. Normally used via the SvNV(sv) and SvNVx(sv) macros.

NV       sv_2nv_flags(      SV * const sv, const I32 flags)
NV  Perl_sv_2nv_flags(pTHX_ SV * const sv, const I32 flags)

#sv_2pv

#sv_2pv_flags

These implement the various forms of the "SvPV" in perlapi macros. The macros are the preferred interface.

These return a pointer to the string value of an SV (coercing it to a string if necessary), and set *lp to its length in bytes.

The forms differ in that plain sv_2pvbyte always processes 'get' magic; and sv_2pvbyte_flags processes 'get' magic if and only if flags contains SV_GMAGIC.

char *       sv_2pv      (      SV *sv, STRLEN *lp)
char *  Perl_sv_2pv      (pTHX_ SV *sv, STRLEN *lp)
char *       sv_2pv_flags(      SV * const sv, STRLEN * const lp,
                                const U32 flags)
char *  Perl_sv_2pv_flags(pTHX_ SV * const sv, STRLEN * const lp,
                                const U32 flags)

#sv_2pvbyte

#sv_2pvbyte_flags

These implement the various forms of the "SvPVbyte" in perlapi macros. The macros are the preferred interface.

These return a pointer to the byte-encoded representation of the SV, and set *lp to its length. If the SV is marked as being encoded as UTF-8, it will be downgraded, if possible, to a byte string. If the SV cannot be downgraded, they croak.

The forms differ in that plain sv_2pvbyte always processes 'get' magic; and sv_2pvbyte_flags processes 'get' magic if and only if flags contains SV_GMAGIC.

char *       sv_2pvbyte      (      SV *sv, STRLEN * const lp)
char *  Perl_sv_2pvbyte      (pTHX_ SV *sv, STRLEN * const lp)
char *       sv_2pvbyte_flags(      SV *sv, STRLEN * const lp,
                                    const U32 flags)
char *  Perl_sv_2pvbyte_flags(pTHX_ SV *sv, STRLEN * const lp,
                                    const U32 flags)

#sv_2pvutf8

#sv_2pvutf8_flags

These implement the various forms of the "SvPVutf8" in perlapi macros. The macros are the preferred interface.

These return a pointer to the UTF-8-encoded representation of the SV, and set *lp to its length in bytes. They may cause the SV to be upgraded to UTF-8 as a side-effect.

The forms differ in that plain sv_2pvutf8 always processes 'get' magic; and sv_2pvutf8_flags processes 'get' magic if and only if flags contains SV_GMAGIC.

char *       sv_2pvutf8      (      SV *sv, STRLEN * const lp)
char *  Perl_sv_2pvutf8      (pTHX_ SV *sv, STRLEN * const lp)
char *       sv_2pvutf8_flags(      SV *sv, STRLEN * const lp,
                                    const U32 flags)
char *  Perl_sv_2pvutf8_flags(pTHX_ SV *sv, STRLEN * const lp,
                                    const U32 flags)

#sv_2uv_flags

Return the unsigned integer value of an SV, doing any necessary string conversion. If flags has the SV_GMAGIC bit set, does an mg_get() first. Normally used via the SvUV(sv) and SvUVx(sv) macros.

UV       sv_2uv_flags(      SV * const sv, const I32 flags)
UV  Perl_sv_2uv_flags(pTHX_ SV * const sv, const I32 flags)

#SvAMAGIC

Returns a boolean as to whether sv has overloading (active magic) enabled or not.

bool  SvAMAGIC(SV * sv)

#SvAMAGIC_off

Indicate that sv has overloading (active magic) disabled.

void       SvAMAGIC_off(SV *sv)
void  Perl_SvAMAGIC_off(SV *sv)

#SvAMAGIC_on

Indicate that sv has overloading (active magic) enabled.

void       SvAMAGIC_on(SV *sv)
void  Perl_SvAMAGIC_on(SV *sv)

#SvBoolFlagsOK

Returns a bool indicating whether the SV has the right flags set such that it is safe to call BOOL_INTERNALS_sv_isbool() or BOOL_INTERNALS_sv_isbool_true() or BOOL_INTERNALS_sv_isbool_false(). Currently equivalent to SvIandPOK(sv) or SvIOK(sv) && SvPOK(sv). Serialization may want to unroll this check. If so you are strongly recommended to add code like assert(SvBoolFlagsOK(sv)); before calling using any of the BOOL_INTERNALS macros.

U32  SvBoolFlagsOK(SV* sv)

#SvCUR

Returns the length, in bytes, of the PV inside the SV. Note that this may not match Perl's length; for that, use sv_len_utf8(sv). See "SvLEN" also.

STRLEN  SvCUR(SV* sv)

#SvCUR_set

Sets the current length, in bytes, of the C string which is in the SV. See "SvCUR" and SvIV_set>.

void  SvCUR_set(SV* sv, STRLEN len)

#SvEND

Returns a pointer to the spot just after the last character in the string which is in the SV, where there is usually a trailing NUL character (even though Perl scalars do not strictly require it). See "SvCUR". Access the character as *(SvEND(sv)).

Warning: If SvCUR is equal to SvLEN, then SvEND points to unallocated memory.

char*  SvEND(SV* sv)

#SvGAMAGIC

Returns true if the SV has get magic or overloading. If either is true then the scalar is active data, and has the potential to return a new value every time it is accessed. Hence you must be careful to only read it once per user logical operation and work with that returned value. If neither is true then the scalar's value cannot change unless written to.

U32  SvGAMAGIC(SV* sv)

#SvGETMAGIC

Invokes "mg_get" on an SV if it has 'get' magic. For example, this will call FETCH on a tied variable. As of 5.37.1, this function is guaranteed to evaluate its argument exactly once.

void       SvGETMAGIC(      SV *sv)
void  Perl_SvGETMAGIC(pTHX_ SV *sv)

#SvGROW

Expands the character buffer in the SV so that it has room for the indicated number of bytes (remember to reserve space for an extra trailing NUL character). Calls sv_grow to perform the expansion if necessary. Returns a pointer to the character buffer. SV must be of type >= SVt_PV. One alternative is to call sv_grow if you are not sure of the type of SV.

You might mistakenly think that len is the number of bytes to add to the existing size, but instead it is the total size sv should be.

char *  SvGROW(SV* sv, STRLEN len)

#SvIandPOK

Returns a bool indicating whether the SV is both SvPOK() and SvIOK() at the same time. Equivalent to SvIOK(sv) && SvPOK(sv) but more efficient.

U32  SvIandPOK(SV* sv)

#SvIandPOK_off

Unsets the PV and IV status of an SV in one operation. Equivalent to SvIOK_off(sv); SvPK_off(v); but more efficient.

void  SvIandPOK_off(SV* sv)

#SvIandPOK_on

Tells an SV that is a string and a number in one operation. Equivalent to SvIOK_on(sv); SvPOK_on(sv); but more efficient.

void  SvIandPOK_on(SV* sv)

#SvIOK

Returns a U32 value indicating whether the SV contains an integer.

U32  SvIOK(SV* sv)

#SvIOK_notUV

Returns a boolean indicating whether the SV contains a signed integer.

bool  SvIOK_notUV(SV* sv)

#SvIOK_off

Unsets the IV status of an SV.

void  SvIOK_off(SV* sv)

#SvIOK_on

Tells an SV that it is an integer.

void  SvIOK_on(SV* sv)

#SvIOK_only

Tells an SV that it is an integer and disables all other OK bits.

void  SvIOK_only(SV* sv)

#SvIOK_only_UV

Tells an SV that it is an unsigned integer and disables all other OK bits.

void  SvIOK_only_UV(SV* sv)

#SvIOK_UV

Returns a boolean indicating whether the SV contains an integer that must be interpreted as unsigned. A non-negative integer whose value is within the range of both an IV and a UV may be flagged as either SvUOK or SvIOK.

bool  SvIOK_UV(SV* sv)

#SvIOKp

Returns a U32 value indicating whether the SV contains an integer. Checks the private setting. Use SvIOK instead.

U32  SvIOKp(SV* sv)

#SvIsBOOL

Returns true if the SV is one of the special boolean constants (PL_sv_yes or PL_sv_no), or is a regular SV whose last assignment stored a copy of one.

bool  SvIsBOOL(SV* sv)

#SvIsCOW

Returns a U32 value indicating whether the SV is Copy-On-Write (either shared hash key scalars, or full Copy On Write scalars if 5.9.0 is configured for COW).

U32  SvIsCOW(SV* sv)

#SvIsCOW_shared_hash

Returns a boolean indicating whether the SV is Copy-On-Write shared hash key scalar.

bool  SvIsCOW_shared_hash(SV* sv)

#SvIV

#SvIV_nomg

#SvIVx

These each coerce the given SV to IV and return it. The returned value in many circumstances will get stored in sv's IV slot, but not in all cases. (Use "sv_setiv" to make sure it does).

As of 5.37.1, all are guaranteed to evaluate sv only once.

SvIVx is now identical to SvIV, but prior to 5.37.1, it was the only form guaranteed to evaluate sv only once.

SvIV_nomg is the same as SvIV, but does not perform 'get' magic.

IV       SvIV     (      SV *sv)
IV  Perl_SvIV     (pTHX_ SV *sv)
IV       SvIV_nomg(      SV *sv)
IV  Perl_SvIV_nomg(pTHX_ SV *sv)
IV       SvIVx    (      SV *sv)

#SvIV_set

Set the value of the IV pointer in sv to val. It is possible to perform the same function of this macro with an lvalue assignment to SvIVX. With future Perls, however, it will be more efficient to use SvIV_set instead of the lvalue assignment to SvIVX.

void  SvIV_set(SV* sv, IV val)

#SvIVX

Returns the raw value in the SV's IV slot, without checks or conversions. Only use when you are sure SvIOK is true. See also "SvIV".

IV  SvIVX(SV* sv)

#SvIVx*

Described under "SvIV"

#SvLEN

Returns the size of the string buffer in the SV, not including any part attributable to SvOOK. See "SvCUR".

STRLEN  SvLEN(SV* sv)

#SvLEN_set

Set the size of the string buffer for the SV. See "SvLEN".

void  SvLEN_set(SV* sv, STRLEN len)

#SvLOCK

Arranges for a mutual exclusion lock to be obtained on sv if a suitable module has been loaded.

void  SvLOCK(SV* sv)

#SvMAGIC_set

Set the value of the MAGIC pointer in sv to val. See "SvIV_set".

void  SvMAGIC_set(SV* sv, MAGIC* val)

#SvNIOK

Returns a U32 value indicating whether the SV contains a number, integer or double.

U32  SvNIOK(SV* sv)

#SvNIOK_off

Unsets the NV/IV status of an SV.

void  SvNIOK_off(SV* sv)

#SvNIOKp

Returns a U32 value indicating whether the SV contains a number, integer or double. Checks the private setting. Use SvNIOK instead.

U32  SvNIOKp(SV* sv)

#SvNOK

Returns a U32 value indicating whether the SV contains a double.

U32  SvNOK(SV* sv)

#SvNOK_off

Unsets the NV status of an SV.

void  SvNOK_off(SV* sv)

#SvNOK_on

Tells an SV that it is a double.

void  SvNOK_on(SV* sv)

#SvNOK_only

Tells an SV that it is a double and disables all other OK bits.

void  SvNOK_only(SV* sv)

#SvNOKp

Returns a U32 value indicating whether the SV contains a double. Checks the private setting. Use SvNOK instead.

U32  SvNOKp(SV* sv)

#SvNV

#SvNV_nomg

#SvNVx

These each coerce the given SV to NV and return it. The returned value in many circumstances will get stored in sv's NV slot, but not in all cases. (Use "sv_setnv" to make sure it does).

As of 5.37.1, all are guaranteed to evaluate sv only once.

SvNVx is now identical to SvNV, but prior to 5.37.1, it was the only form guaranteed to evaluate sv only once.

SvNV_nomg is the same as SvNV, but does not perform 'get' magic.

NV       SvNV     (      SV *sv)
NV  Perl_SvNV     (pTHX_ SV *sv)
NV       SvNV_nomg(      SV *sv)
NV  Perl_SvNV_nomg(pTHX_ SV *sv)
NV       SvNVx    (      SV *sv)

#SvNV_set

Set the value of the NV pointer in sv to val. See "SvIV_set".

void  SvNV_set(SV* sv, NV val)

#SvNVX

Returns the raw value in the SV's NV slot, without checks or conversions. Only use when you are sure SvNOK is true. See also "SvNV".

NV  SvNVX(SV* sv)

#SvNVx*

Described under "SvNV"

#SvOK

Returns a U32 value indicating whether the value is defined. This is only meaningful for scalars.

U32  SvOK(SV* sv)

#SvOOK

Returns a U32 indicating whether the pointer to the string buffer is offset. This hack is used internally to speed up removal of characters from the beginning of a "SvPV". When SvOOK is true, then the start of the allocated string buffer is actually SvOOK_offset() bytes before SvPVX. This offset used to be stored in SvIVX, but is now stored within the spare part of the buffer.

U32  SvOOK(SV* sv)

#SvOOK_off

Remove any string offset.

void  SvOOK_off(SV * sv)

#SvOOK_offset

Reads into len the offset from SvPVX back to the true start of the allocated buffer, which will be non-zero if sv_chop has been used to efficiently remove characters from start of the buffer. Implemented as a macro, which takes the address of len, which must be of type STRLEN. Evaluates sv more than once. Sets len to 0 if SvOOK(sv) is false.

void  SvOOK_offset(SV*sv, STRLEN len)

#SvPOK

Returns a U32 value indicating whether the SV contains a character string.

U32  SvPOK(SV* sv)

#SvPOK_off

Unsets the PV status of an SV.

void  SvPOK_off(SV* sv)

#SvPOK_on

Tells an SV that it is a string.

void  SvPOK_on(SV* sv)

#SvPOK_only

Tells an SV that it is a string and disables all other OK bits. Will also turn off the UTF-8 status.

void  SvPOK_only(SV* sv)

#SvPOK_only_UTF8

Tells an SV that it is a string and disables all other OK bits, and leaves the UTF-8 status as it was.

void  SvPOK_only_UTF8(SV* sv)

#SvPOKp

Returns a U32 value indicating whether the SV contains a character string. Checks the private setting. Use SvPOK instead.

U32  SvPOKp(SV* sv)

#SvPV

#SvPV_const

#SvPV_flags

#SvPV_flags_const

#SvPV_flags_mutable

#SvPV_mutable

#SvPV_nolen

#SvPV_nolen_const

#SvPV_nomg

#SvPV_nomg_const

#SvPV_nomg_const_nolen

#SvPV_nomg_nolen

#SvPVbyte

#SvPVbyte_nolen

#SvPVbyte_nomg

#SvPVbyte_or_null

#SvPVbyte_or_null_nomg

#SvPVbytex

#SvPVbytex_nolen

#SvPVutf8

#SvPVutf8_nolen

#SvPVutf8_nomg

#SvPVutf8_or_null

#SvPVutf8_or_null_nomg

#SvPVutf8x

#SvPVx

#SvPVx_const

#SvPVx_nolen

#SvPVx_nolen_const

These each return a pointer to the string in sv, or a stringified form of sv if it does not contain a string. The SV may cache the stringified version becoming SvPOK.

This is a very basic and common operation, so there are lots of slightly different versions of it.

Note that there is no guarantee that the return value of SvPV(sv), for example, is equal to SvPVX(sv), or that SvPVX(sv) contains valid data, or that successive calls to SvPV(sv) (or another of these forms) will return the same pointer value each time. This is due to the way that things like overloading and Copy-On-Write are handled. In these cases, the return value may point to a temporary buffer or similar. If you absolutely need the SvPVX field to be valid (for example, if you intend to write to it), then see "SvPV_force".

The differences between the forms are:

The forms with neither byte nor utf8 in their names (e.g., SvPV or SvPV_nolen) can expose the SV's internal string buffer. If that buffer consists entirely of bytes 0-255 and includes any bytes above 127, then you MUST consult SvUTF8 to determine the actual code points the string is meant to contain. Generally speaking, it is probably safer to prefer SvPVbyte, SvPVutf8, and the like. See "How do I pass a Perl string to a C library?" in perlguts for more details.

The forms with flags in their names allow you to use the flags parameter to specify to process 'get' magic (by setting the SV_GMAGIC flag) or to skip 'get' magic (by clearing it). The other forms process 'get' magic, except for the ones with nomg in their names, which skip 'get' magic.

The forms that take a len parameter will set that variable to the byte length of the resultant string (these are macros, so don't use &len).

The forms with nolen in their names indicate they don't have a len parameter. They should be used only when it is known that the PV is a C string, terminated by a NUL byte, and without intermediate NUL characters; or when you don't care about its length.

The forms with const in their names return const char * so that the compiler will hopefully complain if you were to try to modify the contents of the string (unless you cast away const yourself).

The other forms return a mutable pointer so that the string is modifiable by the caller; this is emphasized for the ones with mutable in their names.

As of 5.38, all forms are guaranteed to evaluate sv exactly once. For earlier Perls, use a form whose name ends with x for single evaluation.

SvPVutf8 is like SvPV, but converts sv to UTF-8 first if not already UTF-8. Similarly, the other forms with utf8 in their names correspond to their respective forms without.

SvPVutf8_or_null and SvPVutf8_or_null_nomg don't have corresponding non-utf8 forms. Instead they are like SvPVutf8_nomg, but when sv is undef, they return NULL.

SvPVbyte is like SvPV, but converts sv to byte representation first if currently encoded as UTF-8. If sv cannot be downgraded from UTF-8, it croaks. Similarly, the other forms with byte in their names correspond to their respective forms without.

SvPVbyte_or_null doesn't have a corresponding non-byte form. Instead it is like SvPVbyte, but when sv is undef, it returns NULL.

char*        SvPV                 (SV* sv, STRLEN len)
const char*  SvPV_const           (SV* sv, STRLEN len)
char*        SvPV_flags           (SV* sv, STRLEN len, U32 flags)
const char*  SvPV_flags_const     (SV* sv, STRLEN len, U32 flags)
char*        SvPV_flags_mutable   (SV* sv, STRLEN len, U32 flags)
char*        SvPV_mutable         (SV* sv, STRLEN len)
char*        SvPV_nolen           (SV* sv)
const char*  SvPV_nolen_const     (SV* sv)
char*        SvPV_nomg            (SV* sv, STRLEN len)
const char*  SvPV_nomg_const      (SV* sv, STRLEN len)
const char*  SvPV_nomg_const_nolen(SV* sv)
char*        SvPV_nomg_nolen      (SV* sv)
char*        SvPVbyte             (SV* sv, STRLEN len)
char*        SvPVbyte_nolen       (SV* sv)
char*        SvPVbyte_nomg        (SV* sv, STRLEN len)
char*        SvPVbyte_or_null     (SV* sv, STRLEN len)
char*        SvPVbyte_or_null_nomg(SV* sv, STRLEN len)
char*        SvPVbytex            (SV* sv, STRLEN len)
char*        SvPVbytex_nolen      (SV* sv)
char*        SvPVutf8             (SV* sv, STRLEN len)
char*        SvPVutf8_nolen       (SV* sv)
char*        SvPVutf8_nomg        (SV* sv, STRLEN len)
char*        SvPVutf8_or_null     (SV* sv, STRLEN len)
char*        SvPVutf8_or_null_nomg(SV* sv, STRLEN len)
char*        SvPVutf8x            (SV* sv, STRLEN len)
char*        SvPVx                (SV* sv, STRLEN len)
const char*  SvPVx_const          (SV* sv, STRLEN len)
char*        SvPVx_nolen          (SV* sv)
const char*  SvPVx_nolen_const    (SV* sv)

#SvPV_force

#SvPV_force_flags

#SvPV_force_flags_mutable

#SvPV_force_flags_nolen

#SvPV_force_mutable

#SvPV_force_nolen

#SvPV_force_nomg

#SvPV_force_nomg_nolen

#SvPVbyte_force

#SvPVbytex_force

#SvPVutf8_force

#SvPVutf8x_force

#SvPVx_force

These are like "SvPV", returning the string in the SV, but will force the SV into containing a string ("SvPOK"), and only a string ("SvPOK_only"), by hook or by crook. You need to use one of these force routines if you are going to update the "SvPVX" directly.

Note that coercing an arbitrary scalar into a plain PV will potentially strip useful data from it. For example if the SV was SvROK, then the referent will have its reference count decremented, and the SV itself may be converted to an SvPOK scalar with a string buffer containing a value such as "ARRAY(0x1234)".

The differences between the forms are:

The forms with flags in their names allow you to use the flags parameter to specify to perform 'get' magic (by setting the SV_GMAGIC flag) or to skip 'get' magic (by clearing it). The other forms do perform 'get' magic, except for the ones with nomg in their names, which skip 'get' magic.

The forms that take a len parameter will set that variable to the byte length of the resultant string (these are macros, so don't use &len).

The forms with nolen in their names indicate they don't have a len parameter. They should be used only when it is known that the PV is a C string, terminated by a NUL byte, and without intermediate NUL characters; or when you don't care about its length.

The forms with mutable in their names are effectively the same as those without, but the name emphasizes that the string is modifiable by the caller, which it is in all the forms.

SvPVutf8_force is like SvPV_force, but converts sv to UTF-8 first if not already UTF-8.

SvPVutf8x_force is like SvPVutf8_force, but guarantees to evaluate sv only once; use the more efficient SvPVutf8_force otherwise.

SvPVbyte_force is like SvPV_force, but converts sv to byte representation first if currently encoded as UTF-8. If the SV cannot be downgraded from UTF-8, this croaks.

SvPVbytex_force is like SvPVbyte_force, but guarantees to evaluate sv only once; use the more efficient SvPVbyte_force otherwise.

char*  SvPV_force              (SV* sv, STRLEN len)
char*  SvPV_force_flags        (SV * sv, STRLEN len, U32 flags)
char*  SvPV_force_flags_mutable(SV * sv, STRLEN len, U32 flags)
char*  SvPV_force_flags_nolen  (SV * sv, U32 flags)
char*  SvPV_force_mutable      (SV * sv, STRLEN len)
char*  SvPV_force_nolen        (SV* sv)
char*  SvPV_force_nomg         (SV* sv, STRLEN len)
char*  SvPV_force_nomg_nolen   (SV * sv)
char*  SvPVbyte_force          (SV * sv, STRLEN len)
char*  SvPVbytex_force         (SV * sv, STRLEN len)
char*  SvPVutf8_force          (SV * sv, STRLEN len)
char*  SvPVutf8x_force         (SV * sv, STRLEN len)
char*  SvPVx_force             (SV* sv, STRLEN len)

#SvPV_free

Frees the PV buffer in sv, leaving things in a precarious state, so should only be used as part of a larger operation

void  SvPV_free(SV * sv)

#SvPV_mutable*

#SvPV_nolen*

#SvPV_nolen_const*

#SvPV_nomg*

#SvPV_nomg_const*

#SvPV_nomg_const_nolen*

#SvPV_nomg_nolen*

Described under "SvPV"

#SvPV_renew

Low level micro optimization of "SvGROW". It is generally better to use SvGROW instead. This is because SvPV_renew ignores potential issues that SvGROW handles. sv needs to have a real PV that is unencumbered by things like COW. Using SV_CHECK_THINKFIRST or SV_CHECK_THINKFIRST_COW_DROP before calling this should clean it up, but why not just use SvGROW if you're not sure about the provenance?

void  SvPV_renew(SV* sv, STRLEN len)

#SvPV_set

This is probably not what you want to use, you probably wanted "sv_usepvn_flags" or "sv_setpvn" or "sv_setpvs".

Set the value of the PV pointer in sv to the Perl allocated NUL-terminated string val. See also "SvIV_set".

Remember to free the previous PV buffer. There are many things to check. Beware that the existing pointer may be involved in copy-on-write or other mischief, so do SvOOK_off(sv) and use sv_force_normal or SvPV_force (or check the SvIsCOW flag) first to make sure this modification is safe. Then finally, if it is not a COW, call "SvPV_free" to free the previous PV buffer.

void  SvPV_set(SV* sv, char* val)

#SvPV_shrink_to_cur

Trim any trailing unused memory in the PV of sv, which needs to have a real PV that is unencumbered by things like COW. Think first before using this functionality. Is the space saving really worth giving up COW? Will the needed size of sv stay the same?

If the answers are both yes, then use "SV_CHECK_THINKFIRST" or "SV_CHECK_THINKFIRST_COW_DROP" before calling this.

void  SvPV_shrink_to_cur(SV* sv)

#SvPVbyte*

Described under "SvPV"

#SvPVbyte_force*

Described under "SvPV_force"

#SvPVbyte_nolen*

#SvPVbyte_nomg*

#SvPVbyte_or_null*

#SvPVbyte_or_null_nomg*

#SvPVbytex*

Described under "SvPV"

#SvPVbytex_force*

Described under "SvPV_force"

#SvPVbytex_nolen*

Described under "SvPV"

#SvPVCLEAR

Ensures that sv is a SVt_PV and that its SvCUR is 0, and that it is properly null terminated. Equivalent to sv_setpvs(""), but more efficient.

char *  SvPVCLEAR(SV* sv)

#SvPVCLEAR_FRESH

Like SvPVCLEAR, but optimized for newly-minted SVt_PV/PVIV/PVNV/PVMG that already have a PV buffer allocated, but no SvTHINKFIRST.

char *  SvPVCLEAR_FRESH(SV* sv)

#SvPVutf8*

Described under "SvPV"

#SvPVutf8_force*

Described under "SvPV_force"

#SvPVutf8_nolen*

#SvPVutf8_nomg*

#SvPVutf8_or_null*

#SvPVutf8_or_null_nomg*

#SvPVutf8x*

Described under "SvPV"

#SvPVutf8x_force*

Described under "SvPV_force"

#SvPVX

#SvPVX_const

#SvPVX_mutable

#SvPVXx

These return a pointer to the physical string in the SV. The SV must contain a string. Prior to 5.9.3 it is not safe to execute these unless the SV's type >= SVt_PV.

These are also used to store the name of an autoloaded subroutine in an XS AUTOLOAD routine. See "Autoloading with XSUBs" in perlguts.

SvPVXx is identical to SvPVX.

SvPVX_mutable is merely a synonym for SvPVX, but its name emphasizes that the string is modifiable by the caller.

SvPVX_const differs in that the return value has been cast so that the compiler will complain if you were to try to modify the contents of the string, (unless you cast away const yourself).

char*        SvPVX        (SV* sv)
const char*  SvPVX_const  (SV* sv)
char*        SvPVX_mutable(SV* sv)
char*        SvPVXx       (SV* sv)

#SvPVx*

#SvPVx_const*

Described under "SvPV"

#SvPVx_force*

Described under "SvPV_force"

#SvPVx_nolen*

#SvPVx_nolen_const*

Described under "SvPV"

#SvPVXtrue

Returns a boolean as to whether or not sv contains a PV that is considered TRUE. FALSE is returned if sv doesn't contain a PV, or if the PV it does contain is zero length, or consists of just the single character '0'. Every other PV value is considered TRUE.

As of Perl v5.37.1, sv is evaluated exactly once; in earlier releases, it could be evaluated more than once.

bool       SvPVXtrue(      SV *sv)
bool  Perl_SvPVXtrue(pTHX_ SV *sv)

#SvPVXx*

Described under "SvPVX"

#SvREADONLY

Returns true if the argument is readonly, otherwise returns false. Exposed to perl code via Internals::SvREADONLY().

U32  SvREADONLY(SV* sv)

#SvREADONLY_off

Mark an object as not-readonly. Exactly what this mean depends on the object type. Exposed to perl code via Internals::SvREADONLY().

U32  SvREADONLY_off(SV* sv)

#SvREADONLY_on

Mark an object as readonly. Exactly what this means depends on the object type. Exposed to perl code via Internals::SvREADONLY().

U32  SvREADONLY_on(SV* sv)

#SvREFCNT

Returns the value of the object's reference count. Exposed to perl code via Internals::SvREFCNT().

U32  SvREFCNT(SV* sv)

#SvREFCNT_dec

#SvREFCNT_dec_set_NULL

#SvREFCNT_dec_ret_NULL

#SvREFCNT_dec_NN

These decrement the reference count of the given SV.

SvREFCNT_dec_NN may only be used when sv is known to not be NULL.

The function SvREFCNT_dec_ret_NULL() is identical to the SvREFCNT_dec() except it returns a NULL SV *. It is used by SvREFCNT_dec_set_NULL() which is a macro which will, when passed a non-NULL argument, decrement the reference count of its argument and then set it to NULL. You can replace code of the following form:

if (sv) {
   SvREFCNT_dec_NN(sv);
   sv = NULL;
}

with

SvREFCNT_dec_set_NULL(sv);

void       SvREFCNT_dec         (      SV *sv)
void  Perl_SvREFCNT_dec         (pTHX_ SV *sv)
void       SvREFCNT_dec_set_NULL(      SV *sv)
SV *       SvREFCNT_dec_ret_NULL(      SV *sv)
SV *  Perl_SvREFCNT_dec_ret_NULL(pTHX_ SV *sv)
void       SvREFCNT_dec_NN      (      SV *sv)
void  Perl_SvREFCNT_dec_NN      (pTHX_ SV *sv)

#SvREFCNT_inc

#SvREFCNT_inc_NN

#SvREFCNT_inc_simple

#SvREFCNT_inc_simple_NN

#SvREFCNT_inc_simple_void

#SvREFCNT_inc_simple_void_NN

#SvREFCNT_inc_void

#SvREFCNT_inc_void_NN

These all increment the reference count of the given SV. The ones without void in their names return the SV.

SvREFCNT_inc is the base operation; the rest are optimizations if various input constraints are known to be true; hence, all can be replaced with SvREFCNT_inc.

SvREFCNT_inc_NN can only be used if you know sv is not NULL. Since we don't have to check the NULLness, it's faster and smaller.

SvREFCNT_inc_void can only be used if you don't need the return value. The macro doesn't need to return a meaningful value.

SvREFCNT_inc_void_NN can only be used if you both don't need the return value, and you know that sv is not NULL. The macro doesn't need to return a meaningful value, or check for NULLness, so it's smaller and faster.

SvREFCNT_inc_simple can only be used with expressions without side effects. Since we don't have to store a temporary value, it's faster.

SvREFCNT_inc_simple_NN can only be used with expressions without side effects and you know sv is not NULL. Since we don't have to store a temporary value, nor check for NULLness, it's faster and smaller.

SvREFCNT_inc_simple_void can only be used with expressions without side effects and you don't need the return value.

SvREFCNT_inc_simple_void_NN can only be used with expressions without side effects, you don't need the return value, and you know sv is not NULL.

SV *       SvREFCNT_inc               (SV *sv)
SV *  Perl_SvREFCNT_inc               (SV *sv)
SV *       SvREFCNT_inc_NN            (SV *sv)
SV *  Perl_SvREFCNT_inc_NN            (SV *sv)
SV *       SvREFCNT_inc_simple        (SV *sv)
SV *       SvREFCNT_inc_simple_NN     (SV *sv)
void       SvREFCNT_inc_simple_void   (SV *sv)
void       SvREFCNT_inc_simple_void_NN(SV *sv)
void       SvREFCNT_inc_void          (SV *sv)
void  Perl_SvREFCNT_inc_void          (SV *sv)
void       SvREFCNT_inc_void_NN       (SV *sv)

#SvROK

Tests if the SV is an RV.

U32  SvROK(SV* sv)

#SvROK_off

Unsets the RV status of an SV.

void  SvROK_off(SV* sv)

#SvROK_on

Tells an SV that it is an RV.

void  SvROK_on(SV* sv)

#SvRV

Dereferences an RV to return the SV.

SV*  SvRV(SV* sv)

#SvRV_set

Set the value of the RV pointer in sv to val. See "SvIV_set".

void  SvRV_set(SV* sv, SV* val)

#SvSETMAGIC

Invokes "mg_set" on an SV if it has 'set' magic. This is necessary after modifying a scalar, in case it is a magical variable like $| or a tied variable (it calls STORE). This macro evaluates its argument more than once.

void  SvSETMAGIC(SV* sv)

#SvSetMagicSV

#SvSetMagicSV_nosteal

#SvSetSV

#SvSetSV_nosteal

if dsv is the same as ssv, these do nothing. Otherwise they all call some form of "sv_setsv". They may evaluate their arguments more than once.

The only differences are:

SvSetMagicSV and SvSetMagicSV_nosteal perform any required 'set' magic afterwards on the destination SV; SvSetSV and SvSetSV_nosteal do not.

SvSetSV_nosteal SvSetMagicSV_nosteal call a non-destructive version of sv_setsv.

void  SvSetMagicSV        (SV* dsv, SV* ssv)
void  SvSetMagicSV_nosteal(SV* dsv, SV* ssv)
void  SvSetSV             (SV* dsv, SV* ssv)
void  SvSetSV_nosteal     (SV* dsv, SV* ssv)

#SvSHARE

Arranges for sv to be shared between threads if a suitable module has been loaded.

void  SvSHARE(SV* sv)

#SvSHARED_HASH

Returns the hash for sv created by "newSVpvn_share".

struct hek*  SvSHARED_HASH(SV * sv)

#SvSTASH

Returns the stash of the SV.

HV*  SvSTASH(SV* sv)

#SvSTASH_set

Set the value of the STASH pointer in sv to val. See "SvIV_set".

void  SvSTASH_set(SV* sv, HV* val)

#SvTRUE

#SvTRUE_NN

#SvTRUE_nomg

#SvTRUE_nomg_NN

#SvTRUEx

These return a boolean indicating whether Perl would evaluate the SV as true or false. See "SvOK" for a defined/undefined test.

As of Perl 5.32, all are guaranteed to evaluate sv only once. Prior to that release, only SvTRUEx guaranteed single evaluation; now SvTRUEx is identical to SvTRUE.

SvTRUE_nomg and TRUE_nomg_NN do not perform 'get' magic; the others do unless the scalar is already SvPOK, SvIOK, or SvNOK (the public, not the private flags).

SvTRUE_NN is like "SvTRUE", but sv is assumed to be non-null (NN). If there is a possibility that it is NULL, use plain SvTRUE.

SvTRUE_nomg_NN is like "SvTRUE_nomg", but sv is assumed to be non-null (NN). If there is a possibility that it is NULL, use plain SvTRUE_nomg.

bool       SvTRUE        (      SV *sv)
bool  Perl_SvTRUE        (pTHX_ SV *sv)
bool       SvTRUE_NN     (      SV *sv)
bool  Perl_SvTRUE_NN     (pTHX_ SV *sv)
bool       SvTRUE_nomg   (      SV *sv)
bool  Perl_SvTRUE_nomg   (pTHX_ SV *sv)
bool       SvTRUE_nomg_NN(      SV *sv)
bool       SvTRUEx       (      SV *sv)

#SvTYPE

Returns the type of the SV. See "svtype".

svtype  SvTYPE(SV* sv)

#SvUNLOCK

Releases a mutual exclusion lock on sv if a suitable module has been loaded.

void  SvUNLOCK(SV* sv)

#SvUOK

Returns a boolean indicating whether the SV contains an integer that must be interpreted as unsigned. A non-negative integer whose value is within the range of both an IV and a UV may be flagged as either SvUOK or SvIOK.

bool  SvUOK(SV* sv)

#SvUPGRADE

Used to upgrade an SV to a more complex form. Uses sv_upgrade to perform the upgrade if necessary. See "svtype".

void  SvUPGRADE(SV* sv, svtype type)

#SvUTF8

Returns a U32 value indicating the UTF-8 status of an SV. If things are set-up properly, this indicates whether or not the SV contains UTF-8 encoded data. You should use this after a call to "SvPV" or one of its variants, in case any call to string overloading updates the internal flag.

If you want to take into account the bytes pragma, use "DO_UTF8" instead.

U32  SvUTF8(SV* sv)

#SvUTF8_off

Unsets the UTF-8 status of an SV (the data is not changed, just the flag). Do not use frivolously.

void  SvUTF8_off(SV *sv)

#SvUTF8_on

Turn on the UTF-8 status of an SV (the data is not changed, just the flag). Do not use frivolously.

void  SvUTF8_on(SV *sv)

#SvUV

#SvUV_nomg

#SvUVx

These each coerce the given SV to UV and return it. The returned value in many circumstances will get stored in sv's UV slot, but not in all cases. (Use "sv_setuv" to make sure it does).

As of 5.37.1, all are guaranteed to evaluate sv only once.

SvUVx is now identical to SvUV, but prior to 5.37.1, it was the only form guaranteed to evaluate sv only once.

UV       SvUV     (      SV *sv)
UV  Perl_SvUV     (pTHX_ SV *sv)
UV       SvUV_nomg(      SV *sv)
UV  Perl_SvUV_nomg(pTHX_ SV *sv)
UV       SvUVx    (      SV *sv)

#SvUV_set

Set the value of the UV pointer in sv to val. See "SvIV_set".

void  SvUV_set(SV* sv, UV val)

#SvUVX

Returns the raw value in the SV's UV slot, without checks or conversions. Only use when you are sure SvIOK is true. See also "SvUV".

UV  SvUVX(SV* sv)

#SvUVx*

Described under "SvUV"

#SvUVXx

DEPRECATED! It is planned to remove SvUVXx from a future release of Perl. Do not use it for new code; remove it from existing code.

This is an unnecessary synonym for "SvUVX"

UV  SvUVXx(SV* sv)

#SvVOK

Returns a boolean indicating whether the SV contains a v-string.

bool  SvVOK(SV* sv)

#SvVSTRING_mg

Returns the vstring magic, or NULL if none

MAGIC*  SvVSTRING_mg(SV * sv)

#uiv_2buf

This function converts an IV or UV to its string representation.

It is used internally by sv_2pv_flags() and do_print().

char *       uiv_2buf(char * const buf, const IV iv, UV uv,
                      const int is_uv, char ** const peob)
char *  Perl_uiv_2buf(char * const buf, const IV iv, UV uv,
                      const int is_uv, char ** const peob)

#vnewSVpvf

Like "newSVpvf" but the arguments are an encapsulated argument list.

SV *       vnewSVpvf(      const char * const pat,
                           va_list * const args)
SV *  Perl_vnewSVpvf(pTHX_ const char * const pat,
                           va_list * const args)

#Tainting

#SvTAINT

Taints an SV if tainting is enabled, and if some input to the current expression is tainted--usually a variable, but possibly also implicit inputs such as locale settings. SvTAINT propagates that taintedness to the outputs of an expression in a pessimistic fashion; i.e., without paying attention to precisely which outputs are influenced by which inputs.

void  SvTAINT(SV* sv)

#SvTAINTED

Checks to see if an SV is tainted. Returns TRUE if it is, FALSE if not.

bool  SvTAINTED(SV* sv)

#SvTAINTED_off

Untaints an SV. Be very careful with this routine, as it short-circuits some of Perl's fundamental security features. XS module authors should not use this function unless they fully understand all the implications of unconditionally untainting the value. Untainting should be done in the standard perl fashion, via a carefully crafted regexp, rather than directly untainting variables.

void  SvTAINTED_off(SV* sv)

#SvTAINTED_on

Marks an SV as tainted if tainting is enabled.

void  SvTAINTED_on(SV* sv)

#Time

#ASCTIME_R_PROTO

This symbol encodes the prototype of asctime_r. It is zero if d_asctime_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_asctime_r is defined.

#CTIME_R_PROTO

This symbol encodes the prototype of ctime_r. It is zero if d_ctime_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_ctime_r is defined.

#GMTIME_MAX

This symbol contains the maximum value for the time_t offset that the system function gmtime () accepts, and defaults to 0

#GMTIME_MIN

This symbol contains the minimum value for the time_t offset that the system function gmtime () accepts, and defaults to 0

#GMTIME_R_PROTO

This symbol encodes the prototype of gmtime_r. It is zero if d_gmtime_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_gmtime_r is defined.

#HAS_ASCTIME_R

This symbol, if defined, indicates that the asctime_r routine is available to asctime re-entrantly.

#HAS_ASCTIME64

This symbol, if defined, indicates that the asctime64 () routine is available to do the 64bit variant of asctime ()

#HAS_CTIME_R

This symbol, if defined, indicates that the ctime_r routine is available to ctime re-entrantly.

#HAS_CTIME64

This symbol, if defined, indicates that the ctime64 () routine is available to do the 64bit variant of ctime ()

#HAS_DIFFTIME

This symbol, if defined, indicates that the difftime routine is available.

#HAS_DIFFTIME64

This symbol, if defined, indicates that the difftime64 () routine is available to do the 64bit variant of difftime ()

#HAS_FUTIMES

This symbol, if defined, indicates that the futimes routine is available to change file descriptor time stamps with struct timevals.

#HAS_GETITIMER

This symbol, if defined, indicates that the getitimer routine is available to return interval timers.

#HAS_GETTIMEOFDAY

This symbol, if defined, indicates that the gettimeofday() system call is available for a sub-second accuracy clock. Usually, the file sys/resource.h needs to be included (see "I_SYS_RESOURCE"). The type "Timeval" should be used to refer to "struct timeval".

#HAS_GMTIME_R

This symbol, if defined, indicates that the gmtime_r routine is available to gmtime re-entrantly.

#HAS_GMTIME64

This symbol, if defined, indicates that the gmtime64 () routine is available to do the 64bit variant of gmtime ()

#HAS_LOCALTIME_R

This symbol, if defined, indicates that the localtime_r routine is available to localtime re-entrantly.

#HAS_LOCALTIME64

This symbol, if defined, indicates that the localtime64 () routine is available to do the 64bit variant of localtime ()

#HAS_MKTIME

This symbol, if defined, indicates that the mktime routine is available.

#HAS_MKTIME64

This symbol, if defined, indicates that the mktime64 () routine is available to do the 64bit variant of mktime ()

#HAS_NANOSLEEP

This symbol, if defined, indicates that the nanosleep system call is available to sleep with 1E-9 sec accuracy.

#HAS_SETITIMER

This symbol, if defined, indicates that the setitimer routine is available to set interval timers.

#HAS_STRFTIME

This symbol, if defined, indicates that the strftime routine is available to do time formatting.

#HAS_TIME

This symbol, if defined, indicates that the time() routine exists.

#HAS_TIMEGM

This symbol, if defined, indicates that the timegm routine is available to do the opposite of gmtime ()

#HAS_TIMES

This symbol, if defined, indicates that the times() routine exists. Note that this became obsolete on some systems (SUNOS), which now use getrusage(). It may be necessary to include sys/times.h.

#HAS_TM_TM_GMTOFF

This symbol, if defined, indicates to the C program that the struct tm has a tm_gmtoff field.

#HAS_TM_TM_ZONE

This symbol, if defined, indicates to the C program that the struct tm has a tm_zone field.

#HAS_TZNAME

This symbol, if defined, indicates that the tzname[] array is available to access timezone names.

#HAS_USLEEP

This symbol, if defined, indicates that the usleep routine is available to let the process sleep on a sub-second accuracy.

#HAS_USLEEP_PROTO

This symbol, if defined, indicates that the system provides a prototype for the usleep() function. Otherwise, it is up to the program to supply one. A good guess is

extern int usleep(useconds_t);

#I_TIME

This symbol is always defined, and indicates to the C program that it should include time.h.

#ifdef I_TIME
    #include <time.h>
#endif

#I_UTIME

This symbol, if defined, indicates to the C program that it should include utime.h.

#ifdef I_UTIME
    #include <utime.h>
#endif

#L_R_TZSET

If localtime_r() needs tzset, it is defined in this define

#LOCALTIME_MAX

This symbol contains the maximum value for the time_t offset that the system function localtime () accepts, and defaults to 0

#LOCALTIME_MIN

This symbol contains the minimum value for the time_t offset that the system function localtime () accepts, and defaults to 0

#LOCALTIME_R_NEEDS_TZSET

Many libc's localtime_r implementations do not call tzset, making them differ from localtime(), and making timezone changes using $ENV{TZ} without explicitly calling tzset impossible. This symbol makes us call tzset before localtime_r

#LOCALTIME_R_PROTO

This symbol encodes the prototype of localtime_r. It is zero if d_localtime_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_localtime_r is defined.

#mini_mktime

normalise struct tm values without the localtime() semantics (and overhead) of mktime().

void       mini_mktime(struct tm *ptm)
void  Perl_mini_mktime(struct tm *ptm)

#sv_strftime_tm

#sv_strftime_ints

#my_strftime

These implement the libc strftime().

On failure, they return NULL, and set errno to EINVAL.

sv_strftime_tm and sv_strftime_ints are preferred, as they transparently handle the UTF-8ness of the current locale, the input fmt, and the returned result. Only if the current LC_TIME locale is a UTF-8 one (and use bytes is not in effect) will the result be marked as UTF-8.

my_strftime is kept for backwards compatibility. Knowing if its result should be considered UTF-8 or not requires significant extra logic.

Note that all three functions are always executed in the underlying LC_TIME locale of the program, giving results based on that locale.

The functions differ as follows:

sv_strftime_tm takes a pointer to a filled-in struct tm parameter. It ignores the values of the wday and yday fields in it. The other fields give enough information to accurately calculate these values, and are used for that purpose.

The caller assumes ownership of the returned SV with a reference count of 1.

sv_strftime_ints takes a bunch of integer parameters that together completely define a given time. It calculates the struct tm to pass to libc strftime(), and calls that function.

The value of isdst is used as follows:

#0

No daylight savings time is in effect

#>0

Check if daylight savings time is in effect, and adjust the results accordingly.

#<0

This value is reserved for internal use by the POSIX module for backwards compatibility purposes.

The caller assumes ownership of the returned SV with a reference count of 1.

my_strftime is like sv_strftime_ints except that:

#The fmt parameter and the return are char * instead of SV *.

This means the UTF-8ness of the result is unspecified. The result MUST be arranged to be FREED BY THE CALLER).

#The is_dst parameter is ignored.

Daylight savings time is never considered to be in effect.

#It has extra parameters yday and wday that are ignored.

These exist only for historical reasons; the values for the corresponding fields in struct tm are calculated from the other arguments.

Note that all three functions are always executed in the underlying LC_TIME locale of the program, giving results based on that locale.

SV *         sv_strftime_tm  (      SV *fmt,
                                    const struct tm *mytm)
SV *    Perl_sv_strftime_tm  (pTHX_ SV *fmt,
                                    const struct tm *mytm)
SV *         sv_strftime_ints(      SV *fmt, int sec, int min,
                                    int hour, int mday, int mon,
                                    int year, int isdst)
SV *    Perl_sv_strftime_ints(pTHX_ SV *fmt, int sec, int min,
                                    int hour, int mday, int mon,
                                    int year, int isdst)
char *       my_strftime     (      const char *fmt, int sec,
                                    int min, int hour, int mday,
                                    int mon, int year, int wday,
                                    int yday, int isdst)
char *  Perl_my_strftime     (pTHX_ const char *fmt, int sec,
                                    int min, int hour, int mday,
                                    int mon, int year, int wday,
                                    int yday, int isdst)

#Typedef names

#DB_Hash_t

This symbol contains the type of the prefix structure element in the db.h header file. In older versions of DB, it was int, while in newer ones it is size_t.

#DB_Prefix_t

This symbol contains the type of the prefix structure element in the db.h header file. In older versions of DB, it was int, while in newer ones it is u_int32_t.

#Direntry_t

This symbol is set to 'struct direct' or 'struct dirent' depending on whether dirent is available or not. You should use this pseudo type to portably declare your directory entries.

#Fpos_t

This symbol holds the type used to declare file positions in libc. It can be fpos_t, long, uint, etc... It may be necessary to include sys/types.h to get any typedef'ed information.

#Free_t

This variable contains the return type of free(). It is usually void, but occasionally int.

#Gid_t

This symbol holds the return type of getgid() and the type of argument to setrgid() and related functions. Typically, it is the type of group ids in the kernel. It can be int, ushort, gid_t, etc... It may be necessary to include sys/types.h to get any typedef'ed information.

#Gid_t_f

This symbol defines the format string used for printing a Gid_t.

#Gid_t_sign

This symbol holds the signedness of a Gid_t. 1 for unsigned, -1 for signed.

#Gid_t_size

This symbol holds the size of a Gid_t in bytes.

#Groups_t

This symbol holds the type used for the second argument to getgroups() and setgroups(). Usually, this is the same as gidtype (gid_t) , but sometimes it isn't. It can be int, ushort, gid_t, etc... It may be necessary to include sys/types.h to get any typedef'ed information. This is only required if you have getgroups() or setgroups()..

#Malloc_t

This symbol is the type of pointer returned by malloc and realloc.

#Mmap_t

This symbol holds the return type of the mmap() system call (and simultaneously the type of the first argument). Usually set to 'void *' or 'caddr_t'.

#Mode_t

This symbol holds the type used to declare file modes for systems calls. It is usually mode_t, but may be int or unsigned short. It may be necessary to include sys/types.h to get any typedef'ed information.

#Netdb_hlen_t

This symbol holds the type used for the 2nd argument to gethostbyaddr().

#Netdb_host_t

This symbol holds the type used for the 1st argument to gethostbyaddr().

#Netdb_name_t

This symbol holds the type used for the argument to gethostbyname().

#Netdb_net_t

This symbol holds the type used for the 1st argument to getnetbyaddr().

#Off_t

This symbol holds the type used to declare offsets in the kernel. It can be int, long, off_t, etc... It may be necessary to include sys/types.h to get any typedef'ed information.

#Off_t_size

This symbol holds the number of bytes used by the Off_t.

#Pid_t

This symbol holds the type used to declare process ids in the kernel. It can be int, uint, pid_t, etc... It may be necessary to include sys/types.h to get any typedef'ed information.

#Rand_seed_t

This symbol defines the type of the argument of the random seed function.

#Select_fd_set_t

This symbol holds the type used for the 2nd, 3rd, and 4th arguments to select. Usually, this is 'fd_set *', if HAS_FD_SET is defined, and 'int *' otherwise. This is only useful if you have select(), of course.

#Shmat_t

This symbol holds the return type of the shmat() system call. Usually set to 'void *' or 'char *'.

#Signal_t

This symbol's value is either "void" or "int", corresponding to the appropriate return type of a signal handler. Thus, you can declare a signal handler using "Signal_t (*handler)()", and define the handler using "Signal_t handler(sig)".

#Size_t

This symbol holds the type used to declare length parameters for string functions. It is usually size_t, but may be unsigned long, int, etc. It may be necessary to include sys/types.h to get any typedef'ed information.

#Size_t_size

This symbol holds the size of a Size_t in bytes.

#Sock_size_t

This symbol holds the type used for the size argument of various socket calls (just the base type, not the pointer-to).

#SSize_t

This symbol holds the type used by functions that return a count of bytes or an error condition. It must be a signed type. It is usually ssize_t, but may be long or int, etc. It may be necessary to include sys/types.h or unistd.h to get any typedef'ed information. We will pick a type such that sizeof(SSize_t) == sizeof(Size_t).

#Time_t

This symbol holds the type returned by time(). It can be long, or time_t on BSD sites (in which case sys/types.h should be included).

#Uid_t

This symbol holds the type used to declare user ids in the kernel. It can be int, ushort, uid_t, etc... It may be necessary to include sys/types.h to get any typedef'ed information.

#Uid_t_f

This symbol defines the format string used for printing a Uid_t.

#Uid_t_sign

This symbol holds the signedness of a Uid_t. 1 for unsigned, -1 for signed.

#Uid_t_size

This symbol holds the size of a Uid_t in bytes.

#Unicode Support

"Unicode Support" in perlguts has an introduction to this API.

See also "Character classification", "Character case changing", and "String Handling". Various functions outside this section also work specially with Unicode. Search for the string "utf8" in this document.

#BOM_UTF8

This is a macro that evaluates to a string constant of the UTF-8 bytes that define the Unicode BYTE ORDER MARK (U+FEFF) for the platform that perl is compiled on. This allows code to use a mnemonic for this character that works on both ASCII and EBCDIC platforms. sizeof(BOM_UTF8) - 1 can be used to get its length in bytes.

#bytes_cmp_utf8

Compares the sequence of characters (stored as octets) in b, blen with the sequence of characters (stored as UTF-8) in u, ulen. Returns 0 if they are equal, -1 or -2 if the first string is less than the second string, +1 or +2 if the first string is greater than the second string.

-1 or +1 is returned if the shorter string was identical to the start of the longer string. -2 or +2 is returned if there was a difference between characters within the strings.

int       bytes_cmp_utf8(      const U8 *b, STRLEN blen,
                               const U8 *u, STRLEN ulen)
int  Perl_bytes_cmp_utf8(pTHX_ const U8 *b, STRLEN blen,
                               const U8 *u, STRLEN ulen)

#bytes_from_utf8*

Described under "utf8_to_bytes_overwrite"

#bytes_to_utf8

#bytes_to_utf8_free_me

#bytes_to_utf8_temp_pv

These each convert a string s of length *lenp bytes from the native encoding into UTF-8 (UTF-EBCDIC on EBCDIC platforms), returning a pointer to the UTF-8 string, and setting *lenp to its length in bytes.

bytes_to_utf8 always allocates new memory for the result, making sure it is NUL-terminated.

bytes_to_utf8_free_me simply returns a pointer to the input string if the string's UTF-8 representation is the same as its native representation. Otherwise, it behaves like bytes_to_utf8, returning a pointer to new memory containing the conversion of the input. In other words, it returns the input string if converting the string would be a no-op. Note that when no new string is allocated, the function can't add a NUL to the original string if one wasn't already there.

In both cases, the caller is responsible for arranging for any new memory to get freed.

bytes_to_utf8_temp_pv simply returns a pointer to the input string if the string's UTF-8 representation is the same as its native representation, thus behaving like bytes_to_utf8_free_me in this situation. Otherwise, it behaves like bytes_to_utf8, returning a pointer to new memory containing the conversion of the input. The difference is that it also arranges for the new memory to automatically be freed by calling "SAVEFREEPV" on it.

bytes_to_utf8_free_me takes an extra parameter, free_me to communicate. to the caller that memory was allocated or not. If that parameter is NULL, bytes_to_utf8_free_me acts identically to bytes_to_utf8, always allocating new memory.

But when it is a non-NULL pointer, bytes_to_utf8_free_me stores into it either NULL if no memory was allocated; or a pointer to that new memory. This allows the following convenient paradigm:

void * free_me;
U8 converted = bytes_to_utf8_free_me(string, &len, &free_me);
...
Safefree(free_me);

You don't have to know if memory was allocated or not. Just call Safefree unconditionally. free_me will contain a suitable value to pass to Safefree for it to do the right thing, regardless. Your design is likely flawed if you find yourself using free_me for anything other than passing to Safefree.

Upon return, the number of variants in the string can be computed by having saved the value of *lenp before the call, and subtracting the after-call value of *lenp from it.

If you want to convert to UTF-8 from encodings other than the native (Latin1 or EBCDIC), see "sv_recode_to_utf8"().

U8 *       bytes_to_utf8        (      const U8 *s, STRLEN *lenp)
U8 *  Perl_bytes_to_utf8        (pTHX_ const U8 *s, STRLEN *lenp)
U8 *       bytes_to_utf8_free_me(      const U8 *s, STRLEN *lenp,
                                       void **free_me)
U8 *  Perl_bytes_to_utf8_free_me(pTHX_ const U8 *s, STRLEN *lenp,
                                       void **free_me)
U8 *       bytes_to_utf8_temp_pv(      const U8 *s, STRLEN *lenp)
U8 *  Perl_bytes_to_utf8_temp_pv(pTHX_ const U8 *s, STRLEN *lenp)

#c9strict_utf8_to_uv*

Described under "utf8_to_uv"

#DO_UTF8

Returns a bool giving whether or not the PV in sv is to be treated as being encoded in UTF-8.

You should use this after a call to SvPV() or one of its variants, in case any call to string overloading updates the internal UTF-8 encoding flag.

bool  DO_UTF8(SV* sv)

#extended_utf8_to_uv*

Described under "utf8_to_uv"

#foldEQ_utf8

Returns true if the leading portions of the strings s1 and s2 (either or both of which may be in UTF-8) are the same case-insensitively; false otherwise. How far into the strings to compare is determined by other input parameters.

If u1 is true, the string s1 is assumed to be in UTF-8-encoded Unicode; otherwise it is assumed to be in native 8-bit encoding. Correspondingly for u2 with respect to s2.

If the byte length l1 is non-zero, it says how far into s1 to check for fold equality. In other words, s1+l1 will be used as a goal to reach. The scan will not be considered to be a match unless the goal is reached, and scanning won't continue past that goal. Correspondingly for l2 with respect to s2.

If pe1 is non-NULL and the pointer it points to is not NULL, that pointer is considered an end pointer to the position 1 byte past the maximum point in s1 beyond which scanning will not continue under any circumstances. (This routine assumes that UTF-8 encoded input strings are not malformed; malformed input can cause it to read past pe1). This means that if both l1 and pe1 are specified, and pe1 is less than s1+l1, the match will never be successful because it can never get as far as its goal (and in fact is asserted against). Correspondingly for pe2 with respect to s2.

At least one of s1 and s2 must have a goal (at least one of l1 and l2 must be non-zero), and if both do, both have to be reached for a successful match. Also, if the fold of a character is multiple characters, all of them must be matched (see tr21 reference below for 'folding').

Upon a successful match, if pe1 is non-NULL, it will be set to point to the beginning of the next character of s1 beyond what was matched. Correspondingly for pe2 and s2.

For case-insensitiveness, the "casefolding" of Unicode is used instead of upper/lowercasing both the characters, see https://www.unicode.org/reports/tr21/ (Case Mappings).

I32  foldEQ_utf8(const char *s1, char **pe1, UV l1, bool u1,
                 const char *s2, char **pe2, UV l2, bool u2)

#is_ascii_string*

Described under "is_utf8_invariant_string"

#is_c9strict_utf8_string*

#is_c9strict_utf8_string_loc*

#is_c9strict_utf8_string_loclen*

Described under "is_utf8_string"

#is_invariant_string*

Described under "is_utf8_invariant_string"

#is_strict_utf8_string*

#is_strict_utf8_string_loc*

#is_strict_utf8_string_loclen*

Described under "is_utf8_string"

#is_utf8_char_buf*

Described under "isUTF8_CHAR"

#is_utf8_fixed_width_buf_flags

#is_utf8_fixed_width_buf_loc_flags

#is_utf8_fixed_width_buf_loclen_flags

These each return TRUE if the fixed-width buffer starting at s with length len is entirely valid UTF-8, subject to the restrictions given by flags; otherwise they return FALSE.

If flags is 0, any well-formed UTF-8, as extended by Perl, is accepted without restriction. If the final few bytes of the buffer do not form a complete code point, this will return TRUE anyway, provided that "is_utf8_valid_partial_char_flags" returns TRUE for them.

flags can be zero or any combination of the UTF8_DISALLOW_foo flags accepted by "utf8_to_uv", and with the same meanings.

The functions differ from "is_utf8_string_flags" only in that the latter returns FALSE if the final few bytes of the string don't form a complete code point.

is_utf8_fixed_width_buf_loc_flags> does all the preceding, but takes an extra parameter, ep into which it stores the location of the failure, if ep is not NULL. If instead the function returns TRUE, *ep will point to the beginning of any partial character at the end of the buffer; if there is no partial character *ep will contain s+len.

is_utf8_fixed_width_buf_loclen_flags> does all the preceding, but takes another extra parameter, el into which it stores the number of complete, valid characters found, if el is not NULL.

bool       is_utf8_fixed_width_buf_flags       (
                                             const U8 * const s,
                                              STRLEN len,
                                              const U32 flags)
bool       is_utf8_fixed_width_buf_loc_flags   (
                                             const U8 * const s,
                                              STRLEN len,
                                              const U8 **ep,
                                              const U32 flags)
bool       is_utf8_fixed_width_buf_loclen_flags(
                                             const U8 * const s,
                                              STRLEN len,
                                              const U8 **ep,
                                              STRLEN *el,
                                              const U32 flags)
bool  Perl_is_utf8_fixed_width_buf_loclen_flags(
                                             const U8 * const s,
                                              STRLEN len,
                                              const U8 **ep,
                                              STRLEN *el,
                                              const U32 flags)

#is_utf8_invariant_string

#is_utf8_invariant_string_loc

#is_ascii_string

#is_invariant_string

These each return TRUE if the first len bytes of the string s are the same regardless of the UTF-8 encoding of the string (or UTF-EBCDIC encoding on EBCDIC machines); otherwise they returns FALSE. That is, they return TRUE if they are UTF-8 invariant. On ASCII-ish machines, all the ASCII characters and only the ASCII characters fit this definition. On EBCDIC machines, the ASCII-range characters are invariant, but so also are the C1 controls.

If len is 0, it will be calculated using strlen(s), (which means if you use this option, that s can't have embedded NUL characters and has to have a terminating NUL byte).

All forms except is_utf8_invariant_string_loc have identical behavior. The only difference with it is that it has an extra pointer parameter, ep, into which, if it isn't NULL, the location of the first UTF-8 variant character in the ep pointer will be stored upon failure. If all characters are UTF-8 invariant, this function does not change the contents of *ep.

is_invariant_string is somewhat misleadingly named. is_utf8_invariant_string is preferred, as it indicates under what conditions the string is invariant.

is_ascii_string is misleadingly-named. On ASCII-ish platforms, the name isn't misleading: the ASCII-range characters are exactly the UTF-8 invariants. But EBCDIC machines have more UTF-8 invariants than just the ASCII characters, so the name is_utf8_invariant_string is preferred.

See also "is_utf8_string" and "is_utf8_fixed_width_buf_flags".

bool       is_utf8_invariant_string    (const U8 * const s,
                                        STRLEN len)
bool       is_utf8_invariant_string_loc(const U8 * const s,
                                        STRLEN len,
                                        const U8 **ep)
bool  Perl_is_utf8_invariant_string_loc(const U8 * const s,
                                        STRLEN len,
                                        const U8 **ep)
bool       is_ascii_string             (const U8 * const s,
                                        STRLEN len)
bool       is_invariant_string         (const U8 * const s,
                                        STRLEN len)

#is_utf8_string

#is_utf8_string_loc

#is_utf8_string_loclen

#is_strict_utf8_string

#is_strict_utf8_string_loc

#is_strict_utf8_string_loclen

#is_c9strict_utf8_string

#is_c9strict_utf8_string_loc

#is_c9strict_utf8_string_loclen

#is_utf8_string_flags

#is_utf8_string_loc_flags

#is_utf8_string_loclen_flags

These each return TRUE if the first len bytes of string s form a valid UTF-8 string for varying degrees of strictness, FALSE otherwise. If len is 0, it will be calculated using strlen(s) (which means if you use this option, that s can't have embedded NUL characters and has to have a terminating NUL byte). Note that all characters being ASCII constitute 'a valid UTF-8 string'.

Some of the functions also return information about the string. Those that have the suffix _loc in their names have an extra parameter, ep. If that is not NULL, the function stores into it the location of how far it got in parsing s. If the function is returning TRUE, this will be a pointer to the byte immediately after the end of s. If FALSE, it will be the location of the first byte that fails the criteria.

The functions that instead have the suffix _loclen have a second extra parameter, el. They act as the plain _loc functions do with their ep parameter, but if el is not null, the functions store into it the number of UTF-8 encoded characters found at the point where parsing stopped. If the function is returning TRUE, this will be the full count of the UTF-8 characters in s; if FALSE, it will be the count before the first invalid one.

is_utf8_string (and is_utf8_string_loc and is_utf8_string_loclen) consider Perl's extended UTF-8 to be valid. That means that code points above Unicode, surrogates, and non-character code points are all considered valid by this function. Problems may arise in interchange with non-Perl applications, or (unlikely) between machines with different word sizes.

is_strict_utf8_string (and is_strict_utf8_string_loc and is_strict_utf8_string_loclen) consider only Unicode-range (0 to 0x10FFFF) code points to be valid, with the surrogates and non-character code points invalid. This level of strictness is what is safe to accept from outside sources that use Unicode rules.

The forms whose names contain c9strict conform to the level of strictness given in Unicode Corrigendum #9. This means Unicode-range code points including non-character ones are considered valid, but not the surrogates. This level of strictness is considered safe for cooperating components that know how the other components handle non-character code points.

The forms whose names contain _flags allow you to customize the acceptable level of strictness. They have an extra parameter, flags to indicate the types of code points that are acceptable. If flags is 0, they give the same results as "is_utf8_string" (and kin); if flags is UTF8_DISALLOW_ILLEGAL_INTERCHANGE, they give the same results as "is_strict_utf8_string" (and kin); and if flags is UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE, they give the same results as "is_c9strict_utf8_string" (and kin). Otherwise flags may be any combination of the UTF8_DISALLOW_foo flags understood by "utf8_to_uv", with the same meanings.

It's better to use one of the non-_flags functions if they give you the desired strictness, as those have a better chance of being inlined by the C compiler.

See also "is_utf8_invariant_string", "is_utf8_fixed_width_buf_flags",

bool       is_utf8_string                (const U8 *s,
                                          STRLEN len)
bool       is_utf8_string_loc            (const U8 *s,
                                          const STRLEN len,
                                          const U8 **ep)
bool  Perl_is_utf8_string_loc            (const U8 *s,
                                          const STRLEN len,
                                          const U8 **ep)
bool       is_utf8_string_loclen         (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el)
bool  Perl_is_utf8_string_loclen         (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el)
bool       is_strict_utf8_string         (const U8 *s,
                                          STRLEN len)
bool       is_strict_utf8_string_loc     (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep)
bool       is_strict_utf8_string_loclen  (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el)
bool  Perl_is_strict_utf8_string_loclen  (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el)
bool       is_c9strict_utf8_string       (const U8 *s,
                                          STRLEN len)
bool       is_c9strict_utf8_string_loc   (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep)
bool       is_c9strict_utf8_string_loclen(const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el)
bool  Perl_is_c9strict_utf8_string_loclen(const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el)
bool       is_utf8_string_flags          (const U8 *s,
                                          STRLEN len,
                                          const U32 flags)
bool  Perl_is_utf8_string_flags          (const U8 *s,
                                          STRLEN len,
                                          const U32 flags)
bool       is_utf8_string_loc_flags      (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          const U32 flags)
bool       is_utf8_string_loclen_flags   (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el,
                                          const U32 flags)
bool  Perl_is_utf8_string_loclen_flags   (const U8 *s,
                                          STRLEN len,
                                          const U8 **ep,
                                          STRLEN *el,
                                          const U32 flags)

#is_utf8_valid_partial_char

#is_utf8_valid_partial_char_flags

These each return FALSE if the sequence of bytes starting at s and looking no further than e - 1 is the UTF-8 encoding for one or more code points. That is, FALSE is returned if s points to at least one entire UTF-8 encoded character.

Otherwise, they return TRUE if there exists at least one non-empty sequence of bytes that when appended to sequence s, starting at position e causes the entire sequence to be the well-formed UTF-8 of some code point

In other words they return TRUE if s points to an incomplete UTF-8-encoded code point; FALSE otherwise.

This is useful when a fixed-length buffer is being tested for being well-formed UTF-8, but the final few bytes in it don't comprise a full character; that is, it is split somewhere in the middle of the final code point's UTF-8 representation. (Presumably when the buffer is refreshed with the next chunk of data, the new first bytes will complete the partial code point.) This function is used to verify that the final bytes in the current buffer are in fact the legal beginning of some code point, so that if they aren't, the failure can be signalled without having to wait for the next read.

is_utf8_valid_partial_char behaves identically to is_utf8_valid_partial_char_flags when the latter is called with a zero flags parameter. This parameter is used to restrict the classes of code points that are considered to be valid. When zero, Perl's extended UTF-8 is used. Otherwise flags can be any combination of the UTF8_DISALLOW_foo flags accepted by "utf8_to_uv". If there is any sequence of bytes that can complete the input partial character in such a way that a non-prohibited character is formed, the function returns TRUE; otherwise FALSE. Non-character code points cannot be determined based on partial character input, so TRUE is always returned if s looks like it could be the beginning on one of those. But many of the other possible excluded types can be determined from just the first one or two bytes.

bool       is_utf8_valid_partial_char      (const U8 * const s0,
                                            const U8 * const e)
bool       is_utf8_valid_partial_char_flags(const U8 * const s0,
                                            const U8 * const e,
                                            const U32 flags)
bool  Perl_is_utf8_valid_partial_char_flags(const U8 * const s0,
                                            const U8 * const e,
                                            const U32 flags)

#isUTF8_CHAR

#isSTRICT_UTF8_CHAR

#isC9_STRICT_UTF8_CHAR

#isUTF8_CHAR_flags

#is_utf8_char_buf

These each evaluate to non-zero if the first few bytes of the string starting at s and looking no further than e - 1 are well-formed UTF-8 that represents some code point, for varying degrees of strictness. Otherwise they evaluate to 0. If non-zero, the value gives how many bytes starting at s comprise the code point's representation. Any bytes remaining before e, but beyond the ones needed to form the first code point in s, are not examined.

These are used to efficiently decide if the next few bytes in s are legal UTF-8 for a single character.

With isUTF8_CHAR, the code point can be any that will fit in an IV on this machine, using Perl's extension to official UTF-8 to represent those higher than the Unicode maximum of 0x10FFFF. That means that this will consider byte sequences to be valid that are unrecognized or considered illegal by non-Perl applications.

With "isSTRICT_UTF8_CHAR", acceptable code points are restricted to those defined by Unicode to be fully interchangeable across applications. This means code points above the Unicode range (max legal is 0x10FFFF), surrogates, and non-character code points are rejected.

With "isC9_STRICT_UTF8_CHAR", acceptable code points are restricted to those defined by Unicode to be fully interchangeable within an application. This means code points above the Unicode range and surrogates are rejected, but non-character code points are accepted. See Unicode Corrigendum #9.

Use "isUTF8_CHAR_flags" to customize what code points are acceptable. If flags is 0, this gives the same results as "isUTF8_CHAR"; if flags is UTF8_DISALLOW_ILLEGAL_INTERCHANGE, this gives the same results as "isSTRICT_UTF8_CHAR"; and if flags is UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE, this gives the same results as "isC9_STRICT_UTF8_CHAR". Otherwise flags may be any combination of the UTF8_DISALLOW_foo flags understood by "utf8_to_uv", with the same meanings.

The three alternative macros are for the most commonly needed validations; they are likely to run somewhat faster than this more general one, as they can be inlined into your code.

Use one of the "is_utf8_string" forms to check entire strings.

Note also that a UTF-8 "invariant" character (i.e. ASCII on non-EBCDIC machines) is a valid UTF-8 character.

is_utf8_char_buf is the old name for isUTF8_CHAR. Do not use it in new code.

Size_t       isUTF8_CHAR          (const U8 * const s0,
                                   const U8 * const e)
Size_t  Perl_isUTF8_CHAR          (const U8 * const s0,
                                   const U8 * const e)
Size_t       isSTRICT_UTF8_CHAR   (const U8 * const s0,
                                   const U8 * const e)
Size_t  Perl_isSTRICT_UTF8_CHAR   (const U8 * const s0,
                                   const U8 * const e)
Size_t       isC9_STRICT_UTF8_CHAR(const U8 * const s0,
                                   const U8 * const e)
Size_t  Perl_isC9_STRICT_UTF8_CHAR(const U8 * const s0,
                                   const U8 * const e)
Size_t       isUTF8_CHAR_flags    (const U8 * const s0,
                                   const U8 * const e,
                                   const U32 flags)
Size_t  Perl_isUTF8_CHAR_flags    (const U8 * const s0,
                                   const U8 * const e,
                                   const U32 flags)
STRLEN       is_utf8_char_buf     (const U8 *buf,
                                   const U8 *buf_end)
STRLEN  Perl_is_utf8_char_buf     (const U8 *buf,
                                   const U8 *buf_end)

#LATIN1_TO_NATIVE

Returns the native equivalent of the input Latin-1 code point (including ASCII and control characters) given by ch. Thus, LATIN1_TO_NATIVE(66) on EBCDIC platforms returns 194. These each represent the character "B" on their respective platforms. On ASCII platforms no conversion is needed, so this macro expands to just its input, adding no time nor space requirements to the implementation.

For conversion of code points potentially larger than will fit in a character, use "UNI_TO_NATIVE".

U8  LATIN1_TO_NATIVE(U8 ch)

#NATIVE_TO_LATIN1

Returns the Latin-1 (including ASCII and control characters) equivalent of the input native code point given by ch. Thus, NATIVE_TO_LATIN1(193) on EBCDIC platforms returns 65. These each represent the character "A" on their respective platforms. On ASCII platforms no conversion is needed, so this macro expands to just its input, adding no time nor space requirements to the implementation.

For conversion of code points potentially larger than will fit in a character, use "NATIVE_TO_UNI".

U8  NATIVE_TO_LATIN1(U8 ch)

#NATIVE_TO_UNI

Returns the Unicode equivalent of the input native code point given by ch. Thus, NATIVE_TO_UNI(195) on EBCDIC platforms returns 67. These each represent the character "C" on their respective platforms. On ASCII platforms no conversion is needed, so this macro expands to just its input, adding no time nor space requirements to the implementation.

UV  NATIVE_TO_UNI(UV ch)

#pv_uni_display

Build to the scalar dsv a displayable version of the UTF-8 encoded string spv, length len, the displayable version being at most pvlim bytes long (if longer, the rest is truncated and "..." will be appended).

The flags argument can have any combination of these flag bits

#UNI_DISPLAY_ISPRINT

to display isPRINT()able characters as themselves

#UNI_DISPLAY_BACKSLASH

to display the \\[nrfta\\] as the backslashed versions (like "\n")

(UNI_DISPLAY_BACKSLASH is preferred over UNI_DISPLAY_ISPRINT for "\\").

#UNI_DISPLAY_BACKSPACE

to display \b for a backspace, but only when UNI_DISPLAY_BACKSLASH also is set.

#UNI_DISPLAY_REGEX

This a shorthand for UNI_DISPLAY_ISPRINT along with UNI_DISPLAY_BACKSLASH.

#UNI_DISPLAY_QQ

This a shorthand for all three UNI_DISPLAY_ISPRINT, UNI_DISPLAY_BACKSLASH, and UNI_DISPLAY_BACKSLASH.

The pointer to the PV of the dsv is returned.

See also "sv_uni_display".

char *       pv_uni_display(      SV *dsv, const U8 *spv,
                                  STRLEN len, STRLEN pvlim,
                                  UV flags)
char *  Perl_pv_uni_display(pTHX_ SV *dsv, const U8 *spv,
                                  STRLEN len, STRLEN pvlim,
                                  UV flags)

#REPLACEMENT_CHARACTER_UTF8

This is a macro that evaluates to a string constant of the UTF-8 bytes that define the Unicode REPLACEMENT CHARACTER (U+FFFD) for the platform that perl is compiled on. This allows code to use a mnemonic for this character that works on both ASCII and EBCDIC platforms. sizeof(REPLACEMENT_CHARACTER_UTF8) - 1 can be used to get its length in bytes.

#strict_utf8_to_uv*

Described under "utf8_to_uv"

#sv_cat_decode

encoding is assumed to be an Encode object, the PV of ssv is assumed to be octets in that encoding and decoding the input starts from the position which (PV + *offset) pointed to. dsv will be concatenated with the decoded UTF-8 string from ssv. Decoding will terminate when the string tstr appears in decoding output or the input ends on the PV of ssv. The value which offset points will be modified to the last input position on ssv.

Returns TRUE if the terminator was found, else returns FALSE.

bool       sv_cat_decode(      SV *dsv, SV *encoding, SV *ssv,
                               int *offset, char *tstr, int tlen)
bool  Perl_sv_cat_decode(pTHX_ SV *dsv, SV *encoding, SV *ssv,
                               int *offset, char *tstr, int tlen)

#sv_recode_to_utf8

encoding is assumed to be an Encode object, on entry the PV of sv is assumed to be octets in that encoding, and sv will be converted into Unicode (and UTF-8).

If sv already is UTF-8 (or if it is not POK), or if encoding is not a reference, nothing is done to sv. If encoding is not an Encode::XS Encoding object, bad things will happen. (See encoding and Encode.)

The PV of sv is returned.

char *       sv_recode_to_utf8(      SV *sv, SV *encoding)
char *  Perl_sv_recode_to_utf8(pTHX_ SV *sv, SV *encoding)

#sv_uni_display

Build to the scalar dsv a displayable version of the scalar sv, the displayable version being at most pvlim bytes long (if longer, the rest is truncated and "..." will be appended).

The flags argument is as in "pv_uni_display"().

The pointer to the PV of the dsv is returned.

char *       sv_uni_display(      SV *dsv, SV *ssv, STRLEN pvlim,
                                  UV flags)
char *  Perl_sv_uni_display(pTHX_ SV *dsv, SV *ssv, STRLEN pvlim,
                                  UV flags)

#UNI_TO_NATIVE

Returns the native equivalent of the input Unicode code point given by ch. Thus, UNI_TO_NATIVE(68) on EBCDIC platforms returns 196. These each represent the character "D" on their respective platforms. On ASCII platforms no conversion is needed, so this macro expands to just its input, adding no time nor space requirements to the implementation.

UV  UNI_TO_NATIVE(UV ch)

#UNICODE_IS_NONCHAR

Returns a boolean as to whether or not uv is one of the Unicode non-character code points

bool  UNICODE_IS_NONCHAR(const UV uv)

#UNICODE_IS_REPLACEMENT

Returns a boolean as to whether or not uv is the Unicode REPLACEMENT CHARACTER

bool  UNICODE_IS_REPLACEMENT(const UV uv)

#UNICODE_IS_SUPER

Returns a boolean as to whether or not uv is above the maximum legal Unicode code point of U+10FFFF.

bool  UNICODE_IS_SUPER(const UV uv)

#UNICODE_IS_SURROGATE

Returns a boolean as to whether or not uv is one of the Unicode surrogate code points

bool  UNICODE_IS_SURROGATE(const UV uv)

#UNICODE_REPLACEMENT

Evaluates to 0xFFFD, the code point of the Unicode REPLACEMENT CHARACTER

#UTF8_CHK_SKIP*

Described under "UTF8SKIP"

#utf8_distance

Returns the number of UTF-8 characters between the UTF-8 pointers a and b.

WARNING: use only if you *know* that the pointers point inside the same UTF-8 buffer.

IV       utf8_distance(      const U8 *a, const U8 *b)
IV  Perl_utf8_distance(pTHX_ const U8 *a, const U8 *b)

#utf8_hop

Return the UTF-8 pointer s displaced by off characters, either forward (if off is positive) or backward (if negative). s does not need to be pointing to the starting byte of a character. If it isn't, one count of off will be used up to get to the start of the next character for forward hops, and to the start of the current character for negative ones.

WARNING: Prefer "utf8_hop_safe" to this one.

Do NOT use this function unless you know off is within the UTF-8 data pointed to by s and that on entry s is aligned on the first byte of a character or just after the last byte of a character.

U8 *       utf8_hop(const U8 *s, SSize_t off)
U8 *  Perl_utf8_hop(const U8 *s, SSize_t off)

#utf8_hop_back

#utf8_hop_back_overshoot

These each take as input a string encoded as UTF-8 which starts at start, and a position into it given by s, and return the position within it that is s displaced by up to off characters backwards.

If there are fewer than off characters between start and s, the functions return start.

The functions differ in that utf8_hop_back_overshoot can return how many characters off beyond the edge the request was for. When its parameter, &remaining, is not NULL, the function stores into it the count of the excess; zero if the request was completely fulfilled. The actual number of characters that were displaced can then be calculated as off - remaining. This function acts identically to plain utf8_hop_back when this parameter is NULL.

s does not need to be pointing to the starting byte of a character. If it isn't, one count of off will be used up to get to that start.

off must be non-positive, and if zero, no action is taken; s is returned unchanged. That it otherwise must be negative means that the earlier description is a lie, to avoid burdening you with this detail too soon. An off of -2 means to displace two characters backwards, so the displacement is actually the absolute value of off. remaining will also be non-positive. If there was only one character between start and s, and a displacement of -2 was requested, remaining would be set to -1. The subtraction formula works, yielding the result that only -1 character was displaced.

U8 *       utf8_hop_back          (const U8 *s, SSize_t off,
                                   const U8 * const start)
U8 *  Perl_utf8_hop_back          (const U8 *s, SSize_t off,
                                   const U8 * const start)
U8 *       utf8_hop_back_overshoot(const U8 *s, SSize_t off,
                                   const U8 * const start,
                                   SSize_t *remaining)
U8 *  Perl_utf8_hop_back_overshoot(const U8 *s, SSize_t off,
                                   const U8 * const start,
                                   SSize_t *remaining)

#utf8_hop_forward

#utf8_hop_forward_overshoot

These each take as input a position, s0, into a string encoded as UTF-8 which ends at the byte before end, and return the position within it that is s0 displaced by up to off characters forwards.

If there are fewer than off characters between s0 and end, the functions return end.

The functions differ in two ways

• utf8_hop_forward_overshoot can return how many characters beyond the edge the request was for. When its parameter, &remaining, is not NULL, the function stores into it the count of the excess; zero if the request was completely fulfilled. The actual number of characters that were displaced can then be calculated as off - remaining.

• utf8_hop_forward will panic if called with s0 already positioned at or beyond the edge of the string ending at end and the request is to go even further over the edge. utf8_hop_forward_overshoot presumes the caller will handle any errors, and just stores off into remaining without doing anything else.

(The above contains a slight lie. When remaining is NULL, the two functions act identically.)

s0 does not need to be pointing to the starting byte of a character. If it isn't, one count of off will be used up to get to that start.

off must be non-negative, and if zero, no action is taken; s0 is returned unchanged.

U8 *       utf8_hop_forward          (const U8 *s, SSize_t off,
                                      const U8 * const end)
U8 *  Perl_utf8_hop_forward          (const U8 *s, SSize_t off,
                                      const U8 * const end)
U8 *       utf8_hop_forward_overshoot(const U8 *s, SSize_t off,
                                      const U8 * const end,
                                      SSize_t *remaining)
U8 *  Perl_utf8_hop_forward_overshoot(const U8 *s, SSize_t off,
                                      const U8 * const end,
                                      SSize_t *remaining)

#utf8_hop_safe

#utf8_hop_overshoot

These each take as input a string encoded as UTF-8 which starts at start, ending at end, and a position into it given by s, and return the position within it that is s displaced by up to off characters, either forwards if off is positive, or backwards if off is negative. (Nothing is done if off is 0.)

If there are fewer than off characters between s and the respective edge, the functions return that edge.

The functions differ in that utf8_hop_overshoot can return how many characters beyond the edge the request was for. When its parameter, &remaining, is not NULL, the function stores into it the count of the excess; zero if the request was completely fulfilled. The actual number of characters that were displaced can then be calculated as off - remaining. This function acts identically to plain utf8_hop_safe when this parameter is NULL.

s does not need to be pointing to the starting byte of a character. If it isn't, one count of off will be used up to get to that start.

To be more precise, the displacement is by the absolute value of off, and the excess count is the absolute value of remaining.

U8 *       utf8_hop_safe     (const U8 *s, SSize_t off,
                              const U8 * const start,
                              const U8 * const end)
U8 *  Perl_utf8_hop_safe     (const U8 *s, SSize_t off,
                              const U8 * const start,
                              const U8 * const end)
U8 *       utf8_hop_overshoot(const U8 *s, SSize_t off,
                              const U8 * const start,
                              const U8 * const end,
                              SSize_t *remaining)
U8 *  Perl_utf8_hop_overshoot(const U8 *s, SSize_t off,
                              const U8 * const start,
                              const U8 * const end,
                              SSize_t *remaining)

#UTF8_IS_INVARIANT

Evaluates to 1 if the byte c represents the same character when encoded in UTF-8 as when not; otherwise evaluates to 0. UTF-8 invariant characters can be copied as-is when converting to/from UTF-8, saving time.

In spite of the name, this macro gives the correct result if the input string from which c comes is not encoded in UTF-8.

See "UVCHR_IS_INVARIANT" for checking if a UV is invariant.

bool  UTF8_IS_INVARIANT(char c)

#UTF8_IS_NONCHAR

Evaluates to non-zero if the first few bytes of the string starting at s and looking no further than e - 1 are well-formed UTF-8 that represents one of the Unicode non-character code points; otherwise it evaluates to 0. If non-zero, the value gives how many bytes starting at s comprise the code point's representation.

bool  UTF8_IS_NONCHAR(const U8 *s, const U8 *e)

#UTF8_IS_REPLACEMENT

Evaluates to non-zero if the first few bytes of the string starting at s and looking no further than e - 1 are well-formed UTF-8 that represents the Unicode REPLACEMENT CHARACTER; otherwise it evaluates to 0. If non-zero, the value gives how many bytes starting at s comprise the code point's representation.

bool  UTF8_IS_REPLACEMENT(const U8 *s, const U8 *e)

#UTF8_IS_SUPER

Recall that Perl recognizes an extension to UTF-8 that can encode code points larger than the ones defined by Unicode, which are 0..0x10FFFF.

This macro evaluates to non-zero if the first few bytes of the string starting at s and looking no further than e - 1 are from this UTF-8 extension; otherwise it evaluates to 0. If non-zero, the return is how many bytes starting at s comprise the code point's representation.

0 is returned if the bytes are not well-formed extended UTF-8, or if they represent a code point that cannot fit in a UV on the current platform. Hence this macro can give different results when run on a 64-bit word machine than on one with a 32-bit word size.

Note that it is illegal in Perl to have code points that are larger than what can fit in an IV on the current machine; and illegal in Unicode to have any that this macro matches

bool  UTF8_IS_SUPER(const U8 *s, const U8 *e)

#UTF8_IS_SURROGATE

Evaluates to non-zero if the first few bytes of the string starting at s and looking no further than e - 1 are well-formed UTF-8 that represents one of the Unicode surrogate code points; otherwise it evaluates to 0. If non-zero, the value gives how many bytes starting at s comprise the code point's representation.

bool  UTF8_IS_SURROGATE(const U8 *s, const U8 *e)

#utf8_length

Returns the number of characters in the sequence of UTF-8-encoded bytes starting at s and ending at the byte just before e. If <s> and <e> point to the same place, it returns 0 with no warning raised.

If e < s or if the scan would end up past e, it raises a UTF8 warning and returns the number of valid characters.

STRLEN       utf8_length(      const U8 *s0, const U8 *e)
STRLEN  Perl_utf8_length(pTHX_ const U8 *s0, const U8 *e)

#UTF8_MAXBYTES

The maximum width of a single UTF-8 encoded character, in bytes.

NOTE: Strictly speaking Perl's UTF-8 should not be called UTF-8 since UTF-8 is an encoding of Unicode, and Unicode's upper limit, 0x10FFFF, can be expressed with 4 bytes. However, Perl thinks of UTF-8 as a way to encode non-negative integers in a binary format, even those above Unicode.

#UTF8_MAXBYTES_CASE

The maximum number of UTF-8 bytes a single Unicode character can uppercase/lowercase/titlecase/fold into.

#UTF8_SAFE_SKIP*

#UTF8_SKIP*

Described under "UTF8SKIP"

#utf8_to_bytes_overwrite

#utf8_to_bytes_new_pv

#utf8_to_bytes_temp_pv

#utf8_to_bytes

#bytes_from_utf8

NOTE: utf8_to_bytes is experimental and may change or be removed without notice.

These each convert a string encoded as UTF-8 into the equivalent native byte representation, if possible. The first three forms are preferred; their API is more convenient to use, and each return true if the result is in bytes; false if the conversion failed.

• utf8_to_bytes_overwrite

• utf8_to_bytes_new_pv

• utf8_to_bytes_temp_pv

  These differ primarily in the form of the returned string and the allowed constness of the input string. In each, if the input string was already in native bytes or was not convertible, the input isn't changed.

  In each of these three functions, the input s_ptr is a pointer to the string to be converted and *lenp is its length (so that the first byte will be at *sptr[0]).

  utf8_to_bytes_overwrite overwrites the input string with the bytes conversion. Hence, the input string should not be const. (Converting the multi-byte UTF-8 encoding to single bytes never expands the result, so overwriting is always feasible.)

  Both utf8_to_bytes_new_pv and utf8_to_bytes_temp_pv allocate new memory to hold the converted string, never changing the input. Hence the input string may be const. They differ in that utf8_to_bytes_temp_pv arranges for the new memory to automatically be freed. With utf8_to_bytes_new_pv, the caller is responsible for freeing the memory. As explained below, not all successful calls result in new memory being allocated. Hence this function also returns to the caller (via an extra parameter, *free_me) a pointer to any new memory, or NULL if none was allocated.

  The functions return false when the input is not well-formed UTF-8 or contains at least one UTF-8 sequence that represents a code point that can't be expressed as a byte. The contents of *s_ptr and *lenp are not changed. utf8_to_bytes_new_pv sets *free_me to NULL.

  They all return true when either:

  #The input turned out to already be in bytes form

  The contents of *s_ptr and *lenp are not changed. utf8_to_bytes_new_pv sets *free_me to NULL.

  #The input was successfully converted

  #For utf8_to_bytes_overwrite

  The input string *s_ptr was overwritten with the native bytes, including a NUL terminator. *lenp has been updated with the new length.

  #For utf8_to_bytes_new_pv and utf8_to_bytes_temp_pv

  The input string was not changed. Instead, new memory has been allocated containing the translation of the input into native bytes, with a NUL terminator byte. *s_ptr now points to that new memory, and *lenp contains its length.

  For utf8_to_bytes_temp_pv, the new memory has been arranged to be automatically freed, via a call to "SAVEFREEPV".

  For utf8_to_bytes_new_pv, *free_me has been set to *s_ptr, and it is the caller's responsibility to free the new memory when done using it. The following paradigm is convenient to use for this:

  void * free_me;
  if (utf8_to_bytes_new_pv(&s, &len, &free_me) {
     ...
  }
  else {
     ...
  }
  ...
  Safefree(free_me);

  free_me can be used as a boolean (non-NULL meaning true) to indicate that the input was indeed changed if you need to revisit that later in the code. Your design is likely flawed if you find yourself using free_me for any other purpose.

  Note that in all cases, *s_ptr and *lenp will have correct and consistent values, updated as was necessary.

  Also note that upon successful conversion, the number of variants in the string can be computed by having saved the value of *lenp before the call, and subtracting the after-call value of *lenp from it. This is also true for the other two functions described below.

• utf8_to_bytes

  Plain utf8_to_bytes (which has never lost its experimental status) also converts a UTF-8 encoded string to bytes, but there are more glitches that the caller has to be prepared to handle.

  The input string is passed with one less indirection level, s.

  #If the conversion was a noop

  The contents of s and *lenp are not changed, and the function returns s.

  #If the conversion was successful

  The contents of s were changed, and *lenp updated to be the correct length. The function returns s (unchanged).

  #If the conversion failed

  The contents of s were not changed.

  The function returns NULL and sets *lenp to -1, cast to STRLEN. This means that you will have to use a temporary containing the string length to pass to the function if you will need the value afterwards.

• bytes_from_utf8

  bytes_from_utf8 also converts a potentially UTF-8 encoded string s to bytes. It preserves s, allocating new memory for the converted string.

  In contrast to the other functions, the input string to this one need not be UTF-8. If not, the caller has set *is_utf8p to be false, and the function does nothing, returning the original s.

  Also do nothing if there are code points in the string not expressible in native byte encoding, returning the original s.

  Otherwise, *is_utf8p is set to 0, and the return value is a pointer to a newly created string containing the native byte equivalent of s, and whose length is returned in *lenp, updated. The new string is NUL-terminated. The caller is responsible for arranging for the memory used by this string to get freed.

  The major problem with this function is that memory is allocated and filled even when the input string was already in bytes form.

New code should use the first three functions listed above.

bool       utf8_to_bytes_overwrite(      U8 **s_ptr,
                                         STRLEN *lenp)
bool  Perl_utf8_to_bytes_overwrite(pTHX_ U8 **s_ptr,
                                         STRLEN *lenp)
bool       utf8_to_bytes_new_pv   (      U8 const **s_ptr,
                                         STRLEN *lenp,
                                         void **free_me)
bool  Perl_utf8_to_bytes_new_pv   (pTHX_ U8 const **s_ptr,
                                         STRLEN *lenp,
                                         void **free_me)
bool       utf8_to_bytes_temp_pv  (      U8 const **s_ptr,
                                         STRLEN *lenp)
bool  Perl_utf8_to_bytes_temp_pv  (pTHX_ U8 const **s_ptr,
                                         STRLEN *lenp)
U8 *       utf8_to_bytes          (      U8 *s, STRLEN *lenp)
U8 *  Perl_utf8_to_bytes          (pTHX_ U8 *s, STRLEN *lenp)
U8 *       bytes_from_utf8        (      const U8 *s,
                                         STRLEN *lenp,
                                         bool *is_utf8p)
U8 *  Perl_bytes_from_utf8        (pTHX_ const U8 *s,
                                         STRLEN *lenp,
                                         bool *is_utf8p)

#utf8_to_uv

#extended_utf8_to_uv

#strict_utf8_to_uv

#c9strict_utf8_to_uv

#utf8_to_uv_or_die

#utf8_to_uvchr_buf

#utf8_to_uvchr

DEPRECATED! It is planned to remove utf8_to_uvchr from a future release of Perl. Do not use it for new code; remove it from existing code.

These functions each translate from UTF-8 to UTF-32 (or UTF-64 on 64 bit platforms). In other words, to a code point ordinal value. (On EBCDIC platforms, the initial encoding is UTF-EBCDIC, and the output is a native code point).

For example, the string "A" would be converted to the number 65 on an ASCII platform, and to 193 on an EBCDIC one. Converting the string "ABC" would yield the same results, as the functions stop after the first character converted. Converting the string "\N{LATIN CAPITAL LETTER A WITH MACRON} plus anything more in the string" would yield the number 0x100 on both types of platforms, since the first character is U+0100.

The functions whose names contain to_uvchr are older than the functions whose names don't have chr in them. The API in the older functions is harder to use correctly, and so they are kept only for backwards compatibility, and may eventually become deprecated. If you are writing a module and use Devel::PPPort, your code can use the new functions back to at least Perl v5.7.1.

All the functions accept, without complaint, well-formed UTF-8 for any non-problematic Unicode code point 0 .. 0x10FFFF. There are two types of Unicode problematic code points: surrogate characters and non-character code points. (See perlunicode.) Some of the functions reject one or both of these. Private use characters and those code points yet to be assigned to a particular character are never considered problematic. Additionally, most of the functions accept non-Unicode code points, those starting at 0x110000.

There are two sets of these functions:

#utf8_to_uv forms

Almost all code should use only utf8_to_uv, extended_utf8_to_uv, strict_utf8_to_uv, c9strict_utf8_to_uv, or utf8_to_uv_or_die. The other functions are either the problematic old form, or are for specialized uses.

utf8_to_uv_or_die has a simpler interface than the other four, for use when any errors encountered should be fatal. It throws an exception with any errors found, otherwise it returns the code point the input sequence represents.

The other four functions each return true if the sequence of bytes starting at s form a complete, legal UTF-8 (or UTF-EBCDIC) sequence for a code point; or false otherwise. They take an extra parameter, the address of an IV, &cp. *cp will be set to the native code point value the sequence represents, and *advance will be set to its length, in bytes.

If the functions returns false, *cp is set to the Unicode REPLACEMENT CHARACTER, and *advance to the next position along s, where the next possible UTF-8 character could begin. Failing to use this position as the next starting point during parsing of strings has led to successful attacks by crafted inputs.

The functions only examine as many bytes along s as are needed to form a complete UTF-8 representation of a single code point; they never examine the byte at e, or beyond. They return false (or die in the case of utf8_to_uv_or_die) if the code point requires more than e - s bytes to represent.

The functions differ only in what flavor of UTF-8 they accept. All reject syntactically invalid UTF-8.

• strict_utf8_to_uv

  additionally rejects any UTF-8 that translates into a code point that isn't specified by Unicode to be freely exchangeable, namely the surrogate characters and non-character code points (besides non-Unicode code points, any above 0x10FFFF). It does not raise a warning when rejecting these.

• c9strict_utf8_to_uv

  instead uses the exchangeable definition given by Unicode's Corregendum #9, which accepts non-character code points while still rejecting surrogates. It does not raise a warning when rejecting these.

• utf8_to_uv

• utf8_to_uv_or die

  accept all syntactically valid UTF-8, as extended by Perl to allow 64-bit code points to be encoded.

  extended_utf8_to_uv is merely a synonym for utf8_to_uv. Use this form to draw attention to the fact that it accepts any code point. But since Perl programs traditionally do this by default, plain utf8_to_uv is the form most often used.

Whenever syntactically invalid input is rejected, an explanatory warning message is raised, unless utf8 warnings (or the appropriate subcategory) are turned off. A given input sequence may contain multiple malformations, giving rise to multiple warnings, as the functions attempt to find and report on all malformations in a sequence. All the possible malformations are listed in "utf8_to_uv_msgs", with some examples of multiple ones for the same sequence. You can use that function or "utf8_to_uv_flags" to exert more control over the input that is considered acceptable, and the warnings that are raised.

Often, s is an arbitrarily long string containing the UTF-8 representations of many code points in a row, and these functions are called in the course of parsing s to find all those code points.

If your code doesn't know how to deal with illegal input, as would be typical of a low level routine, the loop could look like:

while (s < e) {
    Size_t advance;
    UV cp;
    (void) utf8_to_uv(s, e, &cp, &advance);
    <handle 'cp'>
    s += advance;
}

A REPLACEMENT CHARACTER will be inserted everywhere that malformed input occurs. Obviously, we aren't expecting such outcomes, but your code will be protected from attacks and many harmful effects that could otherwise occur.

If the situation is such that it would be a bug for the input to be invalid, a somewhat simpler loop suffices:

while (s < e) {
    Size_t advance;
    UV cp = utf8_to_uv_or_die(s, e, &advance);
    <handle 'cp'>
    s += advance;
}

This will throw an exception on invalid input, so your code doesn't have to concern itself with that possibility.

If you do have a plan for handling malformed input, you could instead write:

while (s < e) {
    Size_t advance;
    UV cp;
    if (UNLIKELY(! utf8_to_uv(s, e, &cp, &advance)) {
        <bail out or convert to handleable>
    }
    <handle 'cp'>
    s += advance;
}

You may pass NULL to these functions instead of a pointer to your advance variable. But the only legitimate case to do this is if you are only examining the first character in s, and have no plans to ever look further. You could also advance by using UTF8SKIP, but this gives the correct result if and only if the input is well-formed; and this practice has led to successful attacks against such code; and it is extra work always, as the functions have already done the equivalent work and return the correct value in advance, regardless of whether the input is well-formed or not.

Except with utf8_to_uv_or_die, you must always pass a non-NULL pointer into which to store the (first) code point s represents. If you don't care about this value, you should be using one of the "isUTF8_CHAR" functions instead.

#utf8_to_uvchr forms

These are the old form equivalents of utf8_to_uv (and its synonym, extended_utf8_to_uv). They are utf8_to_uvchr and utf8_to_uvchr_buf. There is no old form equivalent of either strict_utf8_to_uv nor c9strict_utf8_to_uv.

utf8_to_uvchr is DEPRECATED. Do NOT use it; it is a security hole ready to bring destruction onto you and yours.

utf8_to_uvchr_buf is discouraged and may eventually become deprecated. It checks if the sequence of bytes starting at s form a complete, legal UTF-8 (or UTF-EBCDIC) sequence for a code point. If so, it returns the code point value the sequence represents, and *retlen will be set to its length, in bytes. Thus, the next possible character in s begins at s + *retlen.

The function only examines as many bytes along s as are needed to form a complete UTF-8 representation of a single code point, but it never examines the byte at e, or beyond.

If the sequence examined starting at s is not legal Perl extended UTF-8, the translation fails, and the resultant behavior unfortunately depends on if the warnings category "utf8" is enabled or not.

#If 'utf8' warnings are disabled

The Unicode REPLACEMENT CHARACTER is silently returned, and *retlen is set (if retlen isn't NULL) so that (s + *retlen) is the next possible position in s that could begin a non-malformed character.

But note that it is ambiguous whether a REPLACEMENT CHARACTER was actually in the input, or if this function synthetically generated one. In the unlikely event that you care, you'd have to examine the input to disambiguate.

#If 'utf8' warnings are enabled

A warning will be displayed, and 0 is returned and *retlen is set (if retlen isn't NULL) to -1.

But note that 0 may also be returned if *s is a legal NUL character. This means that you have to disambiguate a 0 return. You can do this by checking that the first byte of s is indeed a NUL; or by making sure to always pass a non-NULL retlen pointer, and by examining it.

Also note that should you wish to proceed with parsing s, you have no easy way of knowing where to start looking in it for the next possible character. It is important to look in the right place to prevent attacks on your code. It would be better to have instead called an equivalent function that provides this information; any of the utf8_to_uv series, or "utf8n_to_uvchr".

Because of these quirks, utf8_to_uvchr_buf is very difficult to use correctly and handle all cases. Generally, you need to bail out at the first failure it finds.

The deprecated utf8_to_uvchr behaves the same way as utf8_to_uvchr_buf for well-formed input, and for the malformations it is capable of finding, but doesn't find all of them, and it can read beyond the end of the input buffer, which is why it is deprecated.

The utf8_to_uv() family of functions is preferred because they make it easier to write code safe from attacks. You should be converting to them; this will result in simpler, more robust code.

bool       utf8_to_uv         (      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool  Perl_utf8_to_uv         (      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool       extended_utf8_to_uv(      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool  Perl_extended_utf8_to_uv(      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool       strict_utf8_to_uv  (      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool  Perl_strict_utf8_to_uv  (      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool       c9strict_utf8_to_uv(      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
bool  Perl_c9strict_utf8_to_uv(      const U8 * const s,
                                     const U8 * const e,
                                     UV *cp_p, Size_t *advance_p)
UV         utf8_to_uv_or_die  (      const U8 * const s,
                                     const U8 *e,
                                     Size_t *advance_p)
UV    Perl_utf8_to_uv_or_die  (      const U8 * const s,
                                     const U8 *e,
                                     Size_t *advance_p)
UV         utf8_to_uvchr_buf  (      const U8 *s, const U8 *send,
                                     STRLEN *retlen)
UV    Perl_utf8_to_uvchr_buf  (pTHX_ const U8 *s, const U8 *send,
                                     STRLEN *retlen)
UV         utf8_to_uvchr      (      const U8 *s, STRLEN *retlen)
UV    Perl_utf8_to_uvchr      (pTHX_ const U8 *s, STRLEN *retlen)

#utf8_to_uv_errors*

Described under "utf8_to_uv_msgs"

#utf8_to_uv_flags

#utf8n_to_uvchr

These functions are extensions of "utf8_to_uv", where you need more control over what UTF-8 sequences are acceptable. These functions are unlikely to be needed except for specialized purposes.

utf8n_to_uvchr is more like an extension of utf8_to_uvchr_buf, but with fewer quirks, and a different method of specifying the bytes in s it is allowed to examine. It has a curlen parameter instead of an e parameter, so the furthest byte in s it can look at is s + curlen - 1. Its return value is, like utf8_to_uvchr_buf, ambiguous with respect to the NUL and REPLACEMENT characters, but the value of *retlen can be relied on (except with the UTF8_CHECK_ONLY flag described below) to know where the next possible character along s starts, removing that quirk. Hence, you always should use *retlen to determine where the next character in s starts.

These functions have an additional parameter, flags, besides the ones in utf8_to_uv and utf8_to_uvchr_buf, which can be used to broaden or restrict what is acceptable UTF-8. flags has the same meaning and behavior in both functions. When flags is 0, these functions accept any syntactically valid Perl-extended-UTF-8 sequence that doesn't overflow the platform's word size.

There are flags that apply to accepting particular sequences, and flags that apply to raising warnings about encountering sequences. Each type is independent of the other. You can reject and not warn; warn and still accept; or both reject and warn. Rejecting means that the sequence gets translated into the Unicode REPLACEMENT CHARACTER instead of what it was meant to represent.

Unless otherwise stated below, warnings are subject to the utf8 warnings category being on.

#UTF8_CHECK_ONLY

This suppresses any warnings. And it changes what is stored into *retlen with the uvchr family of functions (for the worse). It is not likely to be of use to you. You can use UTF8_ALLOW_ANY (described below) to also turn off warnings, and that flag doesn't adversely affect *retlen.

This flag is ignored if UTF8_DIE_IF_MALFORMED is also set.

#UTF8_FORCE_WARN_IF_MALFORMED

Normally, no warnings are generated if warnings are turned off lexically or globally, regardless of any flags to the contrary. But this flag effectively turns on warnings temporarily for the duration of this function's execution.

Do not use it lightly.

This flag is ignored if UTF8_CHECK_ONLY is also set.

#UTF8_DISALLOW_SURROGATE

#UTF8_WARN_SURROGATE

These reject and/or warn about UTF-8 sequences that represent surrogate characters. The warning categories utf8 and non_unicode control if warnings are actually raised.

#UTF8_DISALLOW_NONCHAR

#UTF8_WARN_NONCHAR

These reject and/or warn about UTF-8 sequences that represent non-character code points. The warning categories utf8 and nonchar control if warnings are actually raised.

#UTF8_DISALLOW_SUPER

#UTF8_WARN_SUPER

These reject and/or warn about UTF-8 sequences that represent code points above 0x10FFFF. The warning categories utf8 and non_unicode control if warnings are actually raised.

#UTF8_DISALLOW_ILLEGAL_INTERCHANGE

#UTF8_WARN_ILLEGAL_INTERCHANGE

These are the same as having selected all three of the corresponding SURROGATE, NONCHAR and SUPER flags listed above.

All such code points are not considered to be safely freely exchangeable between processes.

#UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE

#UTF8_WARN_ILLEGAL_C9_INTERCHANGE

These are the same as having selected both the corresponding SURROGATE and SUPER flags listed above.

Unicode issued Unicode Corrigendum #9 to allow non-character code points to be exchanged by processes aware of the possibility. (They are still discouraged, however.) For more discussion see "Noncharacter code points" in perlunicode.

#UTF8_DISALLOW_PERL_EXTENDED

#UTF8_WARN_PERL_EXTENDED

These reject and/or warn on encountering sequences that require Perl's extension to UTF-8 to represent them. These are all for code points above 0x10FFFF, so these sequences are a subset of the ones controlled by SUPER or either of the illegal interchange sets of flags. The warning categories utf8, non_unicode, and portable control if warnings are actually raised.

Perl predates Unicode, and earlier standards allowed for code points up through 0x7FFF_FFFF (2**31 - 1). Perl, of course, would like you to be able to represent in UTF-8 any code point available on the platform. To do so, some extension must be used to express them. Perl uses a natural extension to UTF-8 to represent the ones up to 2**36-1, and invented a further extension to represent even higher ones, so that any code point that fits in a 64-bit word can be represented. We lump both of these extensions together and refer to them as Perl extended UTF-8. There exist other extensions that people have invented, incompatible with Perl's.

On EBCDIC platforms starting in Perl v5.24, the Perl extension for representing extremely high code points kicks in at 0x3FFF_FFFF (2**30 -1), which is lower than on ASCII. Prior to that, code points 2**31 and higher were simply unrepresentable, and a different, incompatible method was used to represent code points between 2**30 and 2**31 - 1.

It is likely that programs written in something other than Perl would not be able to read files that contain these; nor would Perl understand files written by something that uses a different extension. Hence, you can specify that above-Unicode code points are generally accepted and/or warned about, but still exclude the ones that require this extension to represent.

#UTF8_ALLOW_ANY and kin

Other flags can be passed to allow, in a limited way, syntactic malformations and/or overflowing the number of bits available in a UV on the platform. The functions will not treat the relevant malformations as errors, hence will not raise any warnings for them. utf8_to_uv_msgs will return true.

However, all such malformations translate to the REPLACEMENT CHARACTER, regardless of any of the flags.

The only such flag that you would ever have any reason to use is UTF8_ALLOW_ANY which applies to any of the syntactic malformations and overflow, except for empty input. The other flags are analogous to ones in the _GOT_ bits list in "utf8_to_uv_msgs".

#UTF8_DIE_IF_MALFORMED

If the function would otherwise return false, it instead croaks. The UTF8_FORCE_WARN_IF_MALFORMED flag is effectively turned on so that the cause of the croak is displayed.

bool       utf8_to_uv_flags(const U8 * const s,
                            const U8 * const e, UV *cp_p,
                            Size_t *advance_p, U32 flags)
bool  Perl_utf8_to_uv_flags(const U8 * const s,
                            const U8 * const e, UV *cp_p,
                            Size_t *advance_p, U32 flags)
UV         utf8n_to_uvchr  (const U8 *s, STRLEN curlen,
                            STRLEN *retlen, const U32 flags)
UV    Perl_utf8n_to_uvchr  (const U8 *s, STRLEN curlen,
                            STRLEN *retlen, const U32 flags)

#utf8_to_uv_msgs

#utf8n_to_uvchr_msgs

#utf8_to_uv_errors

#utf8n_to_uvchr_error

These functions are extensions of "utf8_to_uv_flags" and "utf8n_to_uvchr". They are used for the highly specialized purpose of when the caller needs to know the exact malformations that were encountered and/or the diagnostics that would be raised.

They each take one or two extra parameters, pointers to where to store this information. The functions with _msgs in their names return both types, so take two extra parameters; those with _error return just the malformations, so take just one extra parameter. When the extra parameters are both 0, the functions behave identically to the function they extend.

When the errors parameter is not NULL, it should be the address of a U32 variable, into which the functions store a bitmap, described just below, with a bit set for each malformation the function found; 0 if none. The ALLOW-type flags are ignored when determining the content of this variable. That is, even if you "allow" a particular malformation, if it is encountered, the corresponding bit will be set to notify you that one was encountered. However, the bits for conditions that are accepted by default aren't set unless the flags passed to the function indicate that they should be rejected or warned about when encountering them. These are explicitly noted in the list below along with the controlling flags.

The bits returned in errors and their meanings are:

#UTF8_GOT_CONTINUATION

The input sequence was malformed in that the first byte was a UTF-8 continuation byte.

#UTF8_GOT_EMPTY

The input parameters indicated the length of s is 0. Technically, this a coding error, not a malformation; you should check before calling these functions if there is actually anything to convert. But perl needs to be able to recover from bad input, and this is how it does it.

#UTF8_GOT_LONG

The input sequence was malformed in that there is some other sequence that evaluates to the same code point, but that sequence is shorter than this one.

Until Unicode 3.1, it was legal for programs to accept this malformation, but it was discovered that this created security issues.

#UTF8_GOT_NONCHAR

The code point represented by the input UTF-8 sequence is for a Unicode non-character code point. This bit is set only if the input flags parameter contains either the UTF8_DISALLOW_NONCHAR or the UTF8_WARN_NONCHAR flags.

#UTF8_GOT_NON_CONTINUATION

The input sequence was malformed in that a non-continuation-type byte was found in a position where only a continuation-type one should be. See also "UTF8_GOT_SHORT".

#UTF8_GOT_OVERFLOW

The input sequence was malformed in that it is for a code point that is not representable in the number of bits available in an IV on the current platform.

#UTF8_GOT_PERL_EXTENDED

The input sequence is not standard UTF-8, but a Perl extension. This bit is set only if the input flags parameter contains either the UTF8_DISALLOW_PERL_EXTENDED or the UTF8_WARN_PERL_EXTENDED flags.

#UTF8_GOT_SHORT

The input sequence was malformed in that curlen is smaller than required for a complete sequence. In other words, the input is for a partial character sequence.

UTF8_GOT_SHORT and UTF8_GOT_NON_CONTINUATION both indicate a too short sequence. The difference is that UTF8_GOT_NON_CONTINUATION indicates always that there is an error, while UTF8_GOT_SHORT means that an incomplete sequence was looked at. If no other flags are present, it means that the sequence was valid as far as it went. Depending on the application, this could mean one of three things:

• The e or curlen parameters passed in were too small, and the function was prevented from examining all the necessary bytes.

• The buffer being looked at is based on reading data, and the data received so far stopped in the middle of a character, so that the next read will read the remainder of this character. (It is up to the caller to deal with the split bytes somehow.)

• This is a real error, and the partial sequence is all we're going to get.

#UTF8_GOT_SUPER

The input sequence was malformed in that it is for a non-Unicode code point; that is, one above the legal Unicode maximum. This bit is set only if the input flags parameter contains either the UTF8_DISALLOW_SUPER or the UTF8_WARN_SUPER flags.

#UTF8_GOT_SURROGATE

The input sequence was malformed in that it is for a Unicode UTF-16 surrogate code point. This bit is set only if the input flags parameter contains either the UTF8_DISALLOW_SURROGATE or the UTF8_WARN_SURROGATE flags.

Note that more than one bit may have been set by these functions. This is because it is possible for multiple malformations to be present in the same sequence. An example would be an overlong sequence evaluating to a surrogate when surrogates are forbidden. Another example is overflow; standard UTF-8 never overflows, so something that does must have been expressed using Perl's extended UTF-8. It also is above all legal Unicode code points. So there will be a bit set for up to all three of these things. 1) Overflow always; 2) perl-extended if the calling flags indicate those should be rejected or warned about; and 3) above-Unicode, provided the calling flags indicate those should be rejected or warned about.

If you don't care about the system's messages text nor warning categories, you can customize error handling by calling one of the _error functions, using either of the flags UTF8_ALLOW_ANY or UTF8_CHECK_ONLY to suppress any warnings, and then examine the *errors return. If you don't use those flags, warnings will be raised as usual.

But if you do care, instead use one of the functions with _msgs in their names. These allow you to completely customize error handling by suppressing any warnings that would otherwise be raised; instead returning all relevant information in a structure specified by an extra parameter, msgs, a pointer to a variable which has been declared to be an AV*, and into which the function creates a new AV to store information, described below, about all the malformations that were encountered.

When this parameter is non-NULL, the UTF8_DIE_IF_MALFORMED and UTF8_FORCE_WARN_IF_MALFORMED flags are asserted against in DEBUGGING builds, and are ignored in non-DEBUGGING ones. The UTF8_CHECK_ONLY flag is always ignored.

What is considered a malformation is affected by flags, the same as described in "utf8_to_uv_flags". No array element is generated for malformations that are "allowed" by the input flags, in contrast to the bitmap returned in a non-NULL *errors.

Each element of the msgs AV array is an anonymous hash with the following three key-value pairs:

#text

A SVpv containing the text of the message about the problematic input. This text is identical to any warning that otherwise would have been raised if the appropriate warning categories were enabled.

#warn_categories

This is 0 if the flags parameter to the function would ordinarily not have caused the message to be output as a warning; otherwise it is the warning category (or categories) that would have been used to generate a warning for text, packed into a SVuv. For example, if flags contains UTF8_DISALLOW_SURROGATE, but not UTF8_WARN_SURROGATE, this would be 0 if the input was a surrogate.

#flag

A SVuv containing a single flag bit associated with this message. The bit corresponds to some bit in the *errors return value, such as UTF8_GOT_LONG.

The array is sorted so that element [0] contains the first message that would have otherwise been raised; [1], the second; and so on.

You thus can completely override the normal error handling; you can check the lexical warnings state (or not) when choosing what to do with the returned messages.

The caller, of course, is responsible for freeing any returned AV.

bool       utf8_to_uv_msgs     (const U8 * const s0, const U8 *e,
                                UV *cp_p, Size_t *advance_p,
                                U32 flags, U32 *errors,
                                AV **msgs)
bool  Perl_utf8_to_uv_msgs     (const U8 * const s0, const U8 *e,
                                UV *cp_p, Size_t *advance_p,
                                U32 flags, U32 *errors,
                                AV **msgs)
UV         utf8n_to_uvchr_msgs (const U8 * const s0,
                                STRLEN curlen, STRLEN *retlen,
                                const U32 flags, U32 *errors,
                                AV **msgs)
UV    Perl_utf8n_to_uvchr_msgs (const U8 * const s0,
                                STRLEN curlen, STRLEN *retlen,
                                const U32 flags, U32 *errors,
                                AV **msgs)
bool       utf8_to_uv_errors   (const U8 * const s,
                                const U8 * const e, UV *cp_p,
                                Size_t *advance_p, U32 flags,
                                U32 *errors)
bool  Perl_utf8_to_uv_errors   (const U8 * const s,
                                const U8 * const e, UV *cp_p,
                                Size_t *advance_p, U32 flags,
                                U32 *errors)
UV         utf8n_to_uvchr_error(const U8 *s, STRLEN curlen,
                                STRLEN *retlen, const U32 flags,
                                U32 *errors)
UV    Perl_utf8n_to_uvchr_error(const U8 *s, STRLEN curlen,
                                STRLEN *retlen, const U32 flags,
                                U32 *errors)

#utf8_to_uv_or_die*

#utf8_to_uvchr*

#utf8_to_uvchr_buf*

Described under "utf8_to_uv"

#utf8n_to_uvchr*

Described under "utf8_to_uv_flags"

#utf8ness_t

This typedef is used by several core functions that return PV strings, to indicate the UTF-8ness of those strings.

(If you write a new function, you probably should instead return the PV in an SV with the UTF-8 flag of the SV properly set, rather than use this mechanism.)

The possible values this can be are:

#UTF8NESS_YES

This means the string definitely should be treated as a sequence of UTF-8-encoded characters.

Most code that needs to handle this typedef should be of the form:

if (utf8ness_flag == UTF8NESS_YES) {
    treat as utf8;  // like turning on an SV UTF-8 flag
}

#UTF8NESS_NO

This means the string definitely should be treated as a sequence of bytes, not encoded as UTF-8.

#UTF8NESS_IMMATERIAL

This means it is equally valid to treat the string as bytes, or as UTF-8 characters; use whichever way you want. This happens when the string consists entirely of characters which have the same representation whether encoded in UTF-8 or not.

#UTF8NESS_UNKNOWN

This means it is unknown how the string should be treated. No core function will ever return this value to a non-core caller. Instead, it is used by the caller to initialize a variable to a non-legal value. A typical call will look like:

utf8ness_t string_is_utf8 = UTF8NESS_UNKNOWN
const char * string = foo(arg1, arg2, ..., &string_is_utf8);
if (string_is_utf8 == UTF8NESS_YES) {
   do something for UTF-8;
}

The following relationships hold between the enum values:

#0 <= enum value <= UTF8NESS_IMMATERIAL

the string may be treated in code as non-UTF8

#UTF8NESS_IMMATERIAL <= <enum value

the string may be treated in code as encoded in UTF-8

#UTF8SKIP

#UTF8_SKIP

#UTF8_CHK_SKIP

#UTF8_SAFE_SKIP

Each of these returns the number of bytes in the UTF-8 encoded character whose first (perhaps only) byte is pointed to by s.

UTF8SKIP and UTF8_SKIP are synonyms. Use them when there is no possibility that the character pointed to by s is malformed.

If there is a possibility of malformed input, use instead:

#"UTF8_SAFE_SKIP" if you know the maximum ending pointer in the buffer pointed to by s

If the buffer has enough bytes to hold the character, it returns the same value as UTF8SKIP and UTF8_SKIP would. If the buffer has fewer bytes than can fit, it returns the number of bytes available in the buffer, which could be 0 if s >= e. On DEBUGGING builds, it asserts that s <= e.

#"UTF8_CHK_SKIP" if you don't know the maximum ending pointer

This version doesn't blindly assume that the input string pointed to by s is well-formed, but verifies that there isn't a NUL terminating character before the expected end of the next character in s. The length UTF8_CHK_SKIP returns stops just before any such NUL.

Perl tends to add NULs, as an insurance policy, after the end of strings in SV's, so it is likely that using this macro on an SV string will prevent inadvertent reading beyond the end of the input buffer, even if it is malformed UTF-8.

This macro is intended to be used by XS modules where the inputs could be malformed, and it isn't feasible to restructure to use the safer "UTF8_SAFE_SKIP", for example when interfacing with a C library.

STRLEN  UTF8SKIP      (const char* s)
STRLEN  UTF8_SKIP     (const char* s)
STRLEN  UTF8_CHK_SKIP (const char* s)
STRLEN  UTF8_SAFE_SKIP(const char* s, const char* e)

#uv_to_utf8

#uv_to_utf8_flags

#uvchr_to_utf8

#uvchr_to_utf8_flags

These each add the UTF-8 representation of the native code point uv to the end of the string d; d should have at least UVCHR_SKIP(uv)+1 (up to UTF8_MAXBYTES+1) free bytes available. The return value is the pointer to the byte after the end of the new character. In other words,

d = uv_to_utf8(d, uv);

This is the Unicode-aware way of saying

*(d++) = uv;

(uvchr_to_utf8 is a synonym for uv_to_utf8.)

uv_to_utf8_flags is used to make some classes of code points problematic in some way. uv_to_utf8 is effectively the same as calling uv_to_utf8_flags with flags set to 0, meaning no class of code point is considered problematic. That means any input code point from 0..IV_MAX is considered to be fine. IV_MAX is typically 0x7FFF_FFFF in a 32-bit word.

(uvchr_to_utf8_flags is a synonym for uv_to_utf8_flags).

A code point can be problematic in one of two ways. Its use could just raise a warning, and/or it could be forbidden with the function failing, and returning NULL.

The potential classes of problematic code points and the flags that make them so are:

If uv is a Unicode surrogate code point and UNICODE_WARN_SURROGATE is set, the function will raise a warning, provided UTF8 warnings are enabled. If instead UNICODE_DISALLOW_SURROGATE is set, the function will fail and return NULL. If both flags are set, the function will both warn and return NULL.

Similarly, the UNICODE_WARN_NONCHAR and UNICODE_DISALLOW_NONCHAR flags affect how the function handles a Unicode non-character.

And likewise, the UNICODE_WARN_SUPER and UNICODE_DISALLOW_SUPER flags affect the handling of code points that are above the Unicode maximum of 0x10FFFF. Languages other than Perl may not be able to accept files that contain these.

The flag UNICODE_WARN_ILLEGAL_INTERCHANGE selects all three of the above WARN flags; and UNICODE_DISALLOW_ILLEGAL_INTERCHANGE selects all three DISALLOW flags. UNICODE_DISALLOW_ILLEGAL_INTERCHANGE restricts the allowed inputs to the strict UTF-8 traditionally defined by Unicode. Similarly, UNICODE_WARN_ILLEGAL_C9_INTERCHANGE and UNICODE_DISALLOW_ILLEGAL_C9_INTERCHANGE are shortcuts to select the above-Unicode and surrogate flags, but not the non-character ones, as defined in Unicode Corrigendum #9. See "Noncharacter code points" in perlunicode.

Extremely high code points were never specified in any standard, and require an extension to UTF-8 to express, which Perl does. It is likely that programs written in something other than Perl would not be able to read files that contain these; nor would Perl understand files written by something that uses a different extension. For these reasons, there is a separate set of flags that can warn and/or disallow these extremely high code points, even if other above-Unicode ones are accepted. They are the UNICODE_WARN_PERL_EXTENDED and UNICODE_DISALLOW_PERL_EXTENDED flags. For more information see "UTF8_GOT_PERL_EXTENDED". Of course UNICODE_DISALLOW_SUPER will treat all above-Unicode code points, including these, as malformations. (Note that the Unicode standard considers anything above 0x10FFFF to be illegal, but there are standards predating it that allow up to 0x7FFF_FFFF (2**31 -1))

A somewhat misleadingly named synonym for UNICODE_WARN_PERL_EXTENDED is retained for backward compatibility: UNICODE_WARN_ABOVE_31_BIT. Similarly, UNICODE_DISALLOW_ABOVE_31_BIT is usable instead of the more accurately named UNICODE_DISALLOW_PERL_EXTENDED. The names are misleading because on EBCDIC platforms,these flags can apply to code points that actually do fit in 31 bits. The new names accurately describe the situation in all cases.

U8 *       uv_to_utf8         (      U8 *d, UV uv)
U8 *  Perl_uv_to_utf8         (pTHX_ U8 *d, UV uv)
U8 *       uv_to_utf8_flags   (      U8 *d, UV uv, UV flags)
U8 *  Perl_uv_to_utf8_flags   (pTHX_ U8 *d, UV uv, UV flags)
U8 *       uvchr_to_utf8      (      U8 *d, UV uv)
U8 *       uvchr_to_utf8_flags(      U8 *d, UV uv, UV flags)

#uv_to_utf8_msgs

#uvchr_to_utf8_flags_msgs

These functions are identical. THEY SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.

Most code should use "uv_to_utf8_flags"() rather than call this directly.

This function is for code that wants any warning and/or error messages to be returned to the caller rather than be displayed. Any message that would have been displayed if all lexical warnings are enabled will instead be returned.

It is just like "uvchr_to_utf8_flags" but it takes an extra parameter placed after all the others, msgs. If this parameter is 0, this function behaves identically to "uvchr_to_utf8_flags". Otherwise, msgs should be a pointer to an HV * variable, in which this function creates a new HV to contain any appropriate message. The hash has three key-value pairs, as follows:

#text

The text of the message as a SVpv.

#warn_categories

The warning category (or categories) packed into a SVuv.

#flag_bit

A single flag bit associated with this message, in a SVuv. The bit corresponds to some bit in the *errors return value. The possibilities are:

#UNICODE_GOT_SURROGATE

#UNICODE_GOT_NONCHAR

#UNICODE_GOT_SUPER

#UNICODE_GOT_PERL_EXTENDED

It's important to note that specifying this parameter as non-null will cause any warning this function would otherwise generate to be suppressed, and instead be placed in *msgs. The caller can check the lexical warnings state (or not) when choosing what to do with the returned message.

Only a single message is returned; if a code point requires Perl extended UTF-8 to represent, it is also above-Unicode. If either the UNICODE_WARN_PERL_EXTENDED or UNICODE_DISALLOW_PERL_EXTENDED flags are set, the return is controlled by them; if neither is set, the return is controlled by the UNICODE_WARN_SUPER and UNICODE_DISALLOW_SUPER flags.

The caller, of course, is responsible for freeing any returned HV.

U8 *       uv_to_utf8_msgs         (      U8 *d, UV uv, UV flags,
                                          HV **msgs)
U8 *  Perl_uv_to_utf8_msgs         (pTHX_ U8 *d, UV uv, UV flags,
                                          HV **msgs)
U8 *       uvchr_to_utf8_flags_msgs(      U8 *d, UV uv, UV flags,
                                          HV **msgs)

#UVCHR_IS_INVARIANT

Evaluates to 1 if the representation of code point cp is the same whether or not it is encoded in UTF-8; otherwise evaluates to 0. UTF-8 invariant characters can be copied as-is when converting to/from UTF-8, saving time. cp is Unicode if above 255; otherwise is platform-native.

bool  UVCHR_IS_INVARIANT(UV cp)

#UVCHR_SKIP

returns the number of bytes required to represent the code point cp when encoded as UTF-8. cp is a native (ASCII or EBCDIC) code point if less than 255; a Unicode code point otherwise.

STRLEN  UVCHR_SKIP(UV cp)

#uvchr_to_utf8*

#uvchr_to_utf8_flags*

Described under "uv_to_utf8"

#uvchr_to_utf8_flags_msgs*

Described under "uv_to_utf8_msgs"

#Utility Functions

#C_ARRAY_END

Returns a pointer to one element past the final element of the input C array.

void *  C_ARRAY_END(void *a)

#C_ARRAY_LENGTH

Returns the number of elements in the input C array (so you want your zero-based indices to be less than but not equal to).

STRLEN  C_ARRAY_LENGTH(void *a)

#getcwd_sv

Fill sv with current working directory

int       getcwd_sv(      SV *sv)
int  Perl_getcwd_sv(pTHX_ SV *sv)

#IN_PERL_COMPILETIME

Returns 1 if this macro is being called during the compilation phase of the program; otherwise 0;

bool  IN_PERL_COMPILETIME

#IN_PERL_RUNTIME

Returns 1 if this macro is being called during the execution phase of the program; otherwise 0;

bool  IN_PERL_RUNTIME

#IS_SAFE_SYSCALL

Same as "is_safe_syscall".

bool  IS_SAFE_SYSCALL(const char *pv, STRLEN len,
                      const char *what, const char *op_name)

#is_safe_syscall

Test that the given pv (with length len) doesn't contain any internal NUL characters. If it does, set errno to ENOENT, optionally warn using the syscalls category, and return FALSE.

Return TRUE if the name is safe.

what and op_name are used in any warning.

Used by the IS_SAFE_SYSCALL() macro.

bool       is_safe_syscall(      const char *pv, STRLEN len,
                                 const char *what,
                                 const char *op_name)
bool  Perl_is_safe_syscall(pTHX_ const char *pv, STRLEN len,
                                 const char *what,
                                 const char *op_name)

#my_setenv

A wrapper for the C library setenv(3). Don't use the latter, as the perl version has desirable safeguards

void       my_setenv(      const char *nam, const char *val)
void  Perl_my_setenv(pTHX_ const char *nam, const char *val)

#newPADxVOP

Constructs, checks and returns an op containing a pad offset. type is the opcode, which should be one of OP_PADSV, OP_PADAV, OP_PADHV or OP_PADCV. The returned op will have the op_targ field set by the padix argument.

This is convenient when constructing a large optree in nested function calls, as it avoids needing to store the pad op directly to set the op_targ field as a side-effect. For example

o = op_append_elem(OP_LINESEQ, o,
    newPADxVOP(OP_PADSV, 0, padix));

OP *       newPADxVOP(      I32 type, I32 flags, PADOFFSET padix)
OP *  Perl_newPADxVOP(pTHX_ I32 type, I32 flags, PADOFFSET padix)

#phase_name

Returns the given phase's name as a NUL-terminated string.

For example, to print a stack trace that includes the current interpreter phase you might do:

const char* phase_name = phase_name(PL_phase);
mess("This is weird. (Perl phase: %s)", phase_name);

const char * const  phase_name(enum perl_phase)

#PoisonFree

#Poison

These each call PoisonWith(0xEF) for catching access to freed memory.

void  PoisonFree(void* dest, int nitems, type)
void  Poison    (void* dest, int nitems, type)

#PoisonNew

PoisonWith(0xAB) for catching access to allocated but uninitialized memory.

void  PoisonNew(void* dest, int nitems, type)

#PoisonWith

Fill up memory with a byte pattern (a byte repeated over and over again) that hopefully catches attempts to access uninitialized memory.

void  PoisonWith(void* dest, int nitems, type, U8 byte)

#StructCopy

This is an architecture-independent macro that does a shallow copy of one structure to another.

void  StructCopy(type *src, type *dest, type)

#sv_destroyable

Dummy routine which reports that object can be destroyed when there is no sharing module present. It ignores its single SV argument, and returns 'true'. Exists to avoid test for a NULL function pointer and because it could potentially warn under some level of strict-ness.

bool       sv_destroyable(      SV *sv)
bool  Perl_sv_destroyable(pTHX_ SV *sv)

#sv_nosharing

Dummy routine which "shares" an SV when there is no sharing module present. Or "locks" it. Or "unlocks" it. In other words, ignores its single SV argument. Exists to avoid test for a NULL function pointer and because it could potentially warn under some level of strict-ness.

void       sv_nosharing(      SV *sv)
void  Perl_sv_nosharing(pTHX_ SV *sv)

#Versioning

#new_version

Returns a new version object based on the passed in SV:

SV *sv = new_version(SV *ver);

Does not alter the passed in ver SV. See "upg_version" if you want to upgrade the SV.

SV *       new_version(      SV *ver)
SV *  Perl_new_version(pTHX_ SV *ver)

#PERL_REVISION

DEPRECATED! It is planned to remove PERL_REVISION from a future release of Perl. Do not use it for new code; remove it from existing code.

The major number component of the perl interpreter currently being compiled or executing. This has been 5 from 1993 into 2020.

Instead use one of the version comparison macros. See "PERL_VERSION_EQ".

#PERL_SUBVERSION

DEPRECATED! It is planned to remove PERL_SUBVERSION from a future release of Perl. Do not use it for new code; remove it from existing code.

The micro number component of the perl interpreter currently being compiled or executing. In stable releases this gives the dot release number for maintenance updates. In development releases this gives a tag for a snapshot of the status at various points in the development cycle.

Instead use one of the version comparison macros. See "PERL_VERSION_EQ".

#PERL_VERSION

DEPRECATED! It is planned to remove PERL_VERSION from a future release of Perl. Do not use it for new code; remove it from existing code.

The minor number component of the perl interpreter currently being compiled or executing. Between 1993 into 2020, this has ranged from 0 to 33.

Instead use one of the version comparison macros. See "PERL_VERSION_EQ".

#PERL_VERSION_EQ

#PERL_VERSION_GE

#PERL_VERSION_GT

#PERL_VERSION_LE

#PERL_VERSION_LT

#PERL_VERSION_NE

Returns whether or not the perl currently being compiled has the specified relationship to the perl given by the parameters. For example,

#if PERL_VERSION_GT(5,24,2)
  code that will only be compiled on perls after v5.24.2
#else
  fallback code
#endif

Note that this is usable in making compile-time decisions

You may use the special value '*' for the final number to mean ALL possible values for it. Thus,

#if PERL_VERSION_EQ(5,31,'*')

means all perls in the 5.31 series. And

#if PERL_VERSION_NE(5,24,'*')

means all perls EXCEPT 5.24 ones. And

#if PERL_VERSION_LE(5,9,'*')

is effectively

#if PERL_VERSION_LT(5,10,0)

This means you don't have to think so much when converting from the existing deprecated PERL_VERSION to using this macro:

#if PERL_VERSION <= 9

becomes

#if PERL_VERSION_LE(5,9,'*')

bool  PERL_VERSION_EQ(const U8 major, const U8 minor,
                      const U8 patch)
bool  PERL_VERSION_GE(const U8 major, const U8 minor,
                      const U8 patch)
bool  PERL_VERSION_GT(const U8 major, const U8 minor,
                      const U8 patch)
bool  PERL_VERSION_LE(const U8 major, const U8 minor,
                      const U8 patch)
bool  PERL_VERSION_LT(const U8 major, const U8 minor,
                      const U8 patch)
bool  PERL_VERSION_NE(const U8 major, const U8 minor,
                      const U8 patch)

#prescan_version

Validate that a given string can be parsed as a version object, but doesn't actually perform the parsing. Can use either strict or lax validation rules. Can optionally set a number of hint variables to save the parsing code some time when tokenizing.

const char *       prescan_version(      const char *s,
                                         bool strict,
                                         const char **errstr,
                                         bool *sqv,
                                         int *ssaw_decimal,
                                         int *swidth,
                                         bool *salpha)
const char *  Perl_prescan_version(pTHX_ const char *s,
                                         bool strict,
                                         const char **errstr,
                                         bool *sqv,
                                         int *ssaw_decimal,
                                         int *swidth,
                                         bool *salpha)

#scan_version

Returns a pointer to the next character after the parsed version string, as well as upgrading the passed in SV to an RV.

Function must be called with an already existing SV like

sv = newSV(0);
s = scan_version(s, SV *sv, bool qv);

Performs some preprocessing to the string to ensure that it has the correct characteristics of a version. Flags the object if it contains an underscore (which denotes this is an alpha version). The boolean qv denotes that the version should be interpreted as if it had multiple decimals, even if it doesn't.

const char *       scan_version(      const char *s, SV *rv,
                                      bool qv)
const char *  Perl_scan_version(pTHX_ const char *s, SV *rv,
                                      bool qv)

#upg_version

In-place upgrade of the supplied SV to a version object.

SV *sv = upg_version(SV *sv, bool qv);

Returns a pointer to the upgraded SV. Set the boolean qv if you want to force this SV to be interpreted as an "extended" version.

SV *       upg_version(      SV *ver, bool qv)
SV *  Perl_upg_version(pTHX_ SV *ver, bool qv)

#vcmp

Version object aware cmp. Both operands must already have been converted into version objects.

int       vcmp(      SV *lhv, SV *rhv)
int  Perl_vcmp(pTHX_ SV *lhv, SV *rhv)

#vnormal

Accepts a version object and returns the normalized string representation. Call like:

sv = vnormal(rv);

NOTE: you can pass either the object directly or the SV contained within the RV.

The SV returned has a refcount of 1.

SV *       vnormal(      SV *vs)
SV *  Perl_vnormal(pTHX_ SV *vs)

#vnumify

Accepts a version object and returns the normalized floating point representation. Call like:

sv = vnumify(rv);

NOTE: you can pass either the object directly or the SV contained within the RV.

The SV returned has a refcount of 1.

SV *       vnumify(      SV *vs)
SV *  Perl_vnumify(pTHX_ SV *vs)

#vstringify

In order to maintain maximum compatibility with earlier versions of Perl, this function will return either the floating point notation or the multiple dotted notation, depending on whether the original version contained 1 or more dots, respectively.

The SV returned has a refcount of 1.

SV *       vstringify(      SV *vs)
SV *  Perl_vstringify(pTHX_ SV *vs)

#vverify

Validates that the SV contains valid internal structure for a version object. It may be passed either the version object (RV) or the hash itself (HV). If the structure is valid, it returns the HV. If the structure is invalid, it returns NULL.

SV *hv = vverify(sv);

Note that it only confirms the bare minimum structure (so as not to get confused by derived classes which may contain additional hash entries):

• The SV is an HV or a reference to an HV

• The hash contains a "version" key

• The "version" key has a reference to an AV as its value

SV *       vverify(      SV *vs)
SV *  Perl_vverify(pTHX_ SV *vs)

#Warning and Dieing

In all these calls, the U32 wn parameters are warning category constants. You can see the ones currently available in "Category Hierarchy" in warnings, just capitalize all letters in the names and prefix them by WARN_. So, for example, the category void used in a perl program becomes WARN_VOID when used in XS code and passed to one of the calls below.

#ck_warner

#ck_warner_d

If none of the warning categories given by err are enabled, do nothing; otherwise call "warner" or "warner_nocontext" with the passed-in parameters;.

err must be one of the "packWARN", packWARN2, packWARN3, packWARN4 macros populated with the appropriate number of warning categories.

The two forms differ only in that ck_warner_d should be used if warnings for any of the categories are by default enabled.

void  Perl_ck_warner  (pTHX_ U32 err, const char *pat, ...)
void  Perl_ck_warner_d(pTHX_ U32 err, const char *pat, ...)

#ckWARN

#ckWARN2

#ckWARN3

#ckWARN4

These return a boolean as to whether or not warnings are enabled for any of the warning category(ies) parameters: w, w1, ....

Should any of the categories by default be enabled even if not within the scope of use warnings, instead use the "ckWARN_d" macros.

The categories must be completely independent, one may not be subclassed from the other.

bool  ckWARN (U32 w)
bool  ckWARN2(U32 w1, U32 w2)
bool  ckWARN3(U32 w1, U32 w2, U32 w3)
bool  ckWARN4(U32 w1, U32 w2, U32 w3, U32 w4)

#ckWARN_d

#ckWARN2_d

#ckWARN3_d

#ckWARN4_d

Like "ckWARN", but for use if and only if the warning category(ies) is by default enabled even if not within the scope of use warnings.

bool  ckWARN_d (U32 w)
bool  ckWARN2_d(U32 w1, U32 w2)
bool  ckWARN3_d(U32 w1, U32 w2, U32 w3)
bool  ckWARN4_d(U32 w1, U32 w2, U32 w3, U32 w4)

#ckWARN2*

#ckWARN3*

#ckWARN4*

Described under "ckWARN"

#CLEAR_ERRSV

Clear the contents of $@, setting it to the empty string.

This replaces any read-only SV with a fresh SV and removes any magic.

void  CLEAR_ERRSV()

#croak

#croak_nocontext

These are XS interfaces to Perl's die function.

They take a sprintf-style format pattern and argument list, which are used to generate a string message. If the message does not end with a newline, then it will be extended with some indication of the current location in the code, as described for "mess_sv".

The error message will be used as an exception, by default returning control to the nearest enclosing eval, but subject to modification by a $SIG{__DIE__} handler. In any case, these croak functions never return normally.

For historical reasons, if pat is null then the contents of ERRSV ($@) will be used as an error message or object instead of building an error message from arguments. If you want to throw a non-string object, or build an error message in an SV yourself, it is preferable to use the "croak_sv" function, which does not involve clobbering ERRSV.

The two forms differ only in that croak_nocontext does not take a thread context (aTHX) parameter. It is usually preferred as it takes up fewer bytes of code than plain Perl_croak, and time is rarely a critical resource when you are about to throw an exception.

void  Perl_croak          (pTHX_ const char *pat, ...)
void       croak_nocontext(      const char *pat, ...)
void  Perl_croak_nocontext(      const char *pat, ...)

#croak_no_modify

This encapsulates a common reason for dying, generating terser object code than using the generic Perl_croak. It is exactly equivalent to croak("%s", PL_no_modify) (which expands to something like "Modification of a read-only value attempted").

Less code used on exception code paths reduces CPU cache pressure.

void       croak_no_modify()
void  Perl_croak_no_modify()

#croak_nocontext*

Described under "croak"

#croak_sv

This is an XS interface to Perl's die function.

baseex is the error message or object. If it is a reference, it will be used as-is. Otherwise it is used as a string, and if it does not end with a newline then it will be extended with some indication of the current location in the code, as described for "mess_sv".

The error message or object will be used as an exception, by default returning control to the nearest enclosing eval, but subject to modification by a $SIG{__DIE__} handler. In any case, the croak_sv function never returns normally.

To die with a simple string message, the "croak" function may be more convenient.

void       croak_sv(      SV *baseex)
void  Perl_croak_sv(pTHX_ SV *baseex)

#die

#die_nocontext

These behave the same as "croak", except for the return type. They should be used only where the OP * return type is required. They never actually return.

The two forms differ only in that die_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

OP *  Perl_die          (pTHX_ const char *pat, ...)
OP *       die_nocontext(      const char *pat, ...)
OP *  Perl_die_nocontext(      const char *pat, ...)

#die_sv

This behaves the same as "croak_sv", except for the return type. It should be used only where the OP * return type is required. The function never actually returns.

OP *       die_sv(      SV *baseex)
OP *  Perl_die_sv(pTHX_ SV *baseex)

#ERRSV

Returns the SV for $@, creating it if needed.

SV *  ERRSV

#fatal_warner

Like "warner" except that it acts as if fatal warnings are enabled for the warning.

If called when there are pending compilation errors this function may return.

This is currently used to generate "used only once" fatal warnings since the COP where the name being reported is no longer the current COP when the warning is generated and may be useful for similar cases.

err must be one of the "packWARN", packWARN2, packWARN3, packWARN4 macros populated with the appropriate number of warning categories.

void  Perl_fatal_warner(pTHX_ U32 err, const char *pat, ...)

#packWARN

#packWARN2

#packWARN3

#packWARN4

These macros are used to pack warning categories into a single U32 to pass to macros and functions that take a warning category parameter. The number of categories to pack is given by the name, with a corresponding number of category parameters passed.

U32  packWARN (U32 w1)
U32  packWARN2(U32 w1, U32 w2)
U32  packWARN3(U32 w1, U32 w2, U32 w3)
U32  packWARN4(U32 w1, U32 w2, U32 w3, U32 w4)

#SANE_ERRSV

Clean up ERRSV so we can safely set it.

This replaces any read-only SV with a fresh writable copy and removes any magic.

void  SANE_ERRSV()

#sv_regex_global_pos_clear

Resets the value in the regexp global match position magic, if it exists, so that it does not take effect.

void       sv_regex_global_pos_clear(      SV *sv)
void  Perl_sv_regex_global_pos_clear(pTHX_ SV *sv)

#sv_regex_global_pos_get

If the given SV has regexp global match position magic, sets the STRLEN pointed to by posp to the current value of the position and returns true. If not, returns false.

If flags is zero, the return value will count in units of characters. If the SV_POSBYTES flag is present, this will count instead in units of bytes, which may be different if the SV has the SvUTF8 flag set.

bool       sv_regex_global_pos_get(      SV *sv, STRLEN *posp,
                                         U32 flags)
bool  Perl_sv_regex_global_pos_get(pTHX_ SV *sv, STRLEN *posp,
                                         U32 flags)

#sv_regex_global_pos_set

Sets the value in the regexp global match position magic, first adding it if necessary. If pos is given as a negative value, this will count backwards from the end of the string.

If flags is zero, pos will count in units of characters. If the SV_POSBYTES flag is present, this will count instead in units of bytes, which may be different if the SV has the SvUTF8 flag set. In that case, it will be the caller's responsibility to ensure that pos only lands on the boundary between characters, and not in the middle of a multi-byte character.

void       sv_regex_global_pos_set(      SV *sv, STRLEN pos,
                                         U32 flags)
void  Perl_sv_regex_global_pos_set(pTHX_ SV *sv, STRLEN pos,
                                         U32 flags)

#sv_vstring_get

If the given SV has vstring magic, stores the length of it into the variable addressed by lenp, and returns the string pointer. If not, returns NULL.

If a pointer is returned to the caller, it will point to memory owned by the SV itself. The caller is not responsible for freeing it after this call, though it will not remain valid for longer than the lifetime of the SV itself. The caller should take a copy of it if it needs to be accessed after this time.

const char *       sv_vstring_get(      SV * const sv,
                                        STRLEN *lenp)
const char *  Perl_sv_vstring_get(pTHX_ SV * const sv,
                                        STRLEN *lenp)

#vcroak

This is an XS interface to Perl's die function.

pat and args are a sprintf-style format pattern and encapsulated argument list. These are used to generate a string message. If the message does not end with a newline, then it will be extended with some indication of the current location in the code, as described for "mess_sv".

The error message will be used as an exception, by default returning control to the nearest enclosing eval, but subject to modification by a $SIG{__DIE__} handler. In any case, the croak function never returns normally.

For historical reasons, if pat is null then the contents of ERRSV ($@) will be used as an error message or object instead of building an error message from arguments. If you want to throw a non-string object, or build an error message in an SV yourself, it is preferable to use the "croak_sv" function, which does not involve clobbering ERRSV.

void       vcroak(      const char *pat, va_list *args)
void  Perl_vcroak(pTHX_ const char *pat, va_list *args)

#vfatal_warner

This is like "fatal_warner" but args are an encapsulated argument list.

void       vfatal_warner(      U32 err, const char *pat,
                               va_list *args)
void  Perl_vfatal_warner(pTHX_ U32 err, const char *pat,
                               va_list *args)

#vwarn

This is an XS interface to Perl's warn function.

This is like "warn", but args are an encapsulated argument list.

Unlike with "vcroak", pat is not permitted to be null.

void       vwarn(      const char *pat, va_list *args)
void  Perl_vwarn(pTHX_ const char *pat, va_list *args)

#vwarner

This is like "warner", but args are an encapsulated argument list.

void       vwarner(      U32 err, const char *pat, va_list *args)
void  Perl_vwarner(pTHX_ U32 err, const char *pat, va_list *args)

#warn

#warn_nocontext

These are XS interfaces to Perl's warn function.

They take a sprintf-style format pattern and argument list, which are used to generate a string message. If the message does not end with a newline, then it will be extended with some indication of the current location in the code, as described for "mess_sv".

The error message or object will by default be written to standard error, but this is subject to modification by a $SIG{__WARN__} handler.

Unlike with "croak", pat is not permitted to be null.

The two forms differ only in that warn_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

void  Perl_warn          (pTHX_ const char *pat, ...)
void       warn_nocontext(      const char *pat, ...)
void  Perl_warn_nocontext(      const char *pat, ...)

#warn_sv

This is an XS interface to Perl's warn function.

baseex is the error message or object. If it is a reference, it will be used as-is. Otherwise it is used as a string, and if it does not end with a newline then it will be extended with some indication of the current location in the code, as described for "mess_sv".

The error message or object will by default be written to standard error, but this is subject to modification by a $SIG{__WARN__} handler.

To warn with a simple string message, the "warn" function may be more convenient.

void       warn_sv(      SV *baseex)
void  Perl_warn_sv(pTHX_ SV *baseex)

#warner

#warner_nocontext

These output a warning of the specified category (or categories) given by err, using the sprintf-style format pattern pat, and argument list.

err must be one of the "packWARN", packWARN2, packWARN3, packWARN4 macros populated with the appropriate number of warning categories. If any of the warning categories they specify is fatal, a fatal exception is thrown.

In any event a message is generated by the pattern and arguments. If the message does not end with a newline, then it will be extended with some indication of the current location in the code, as described for "mess_sv".

The error message or object will by default be written to standard error, but this is subject to modification by a $SIG{__WARN__} handler.

pat is not permitted to be null.

The two forms differ only in that warner_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

These functions differ from the similarly named "warn" functions, in that the latter are for XS code to unconditionally display a warning, whereas these are for code that may be compiling a perl program, and does extra checking to see if the warning should be fatal.

void  Perl_warner          (pTHX_ U32 err, const char *pat, ...)
void       warner_nocontext(      U32 err, const char *pat, ...)
void  Perl_warner_nocontext(      U32 err, const char *pat, ...)

#XS

xsubpp compiles XS code into C. See "xsubpp" in perlutil.

#aMY_CXT

#aMY_CXT_

#_aMY_CXT

Described in perlxs.

#ax

Variable which is setup by xsubpp to indicate the stack base offset, used by the ST, XSprePUSH and XSRETURN macros. The dMARK macro must be called prior to setup the MARK variable.

Stack_off_t  ax

#CLASS

Variable which is setup by xsubpp to indicate the class name for a C++ XS constructor. This is always a char*. See "THIS".

char*  CLASS

#dAX

Sets up the ax variable. This is usually handled automatically by xsubpp by calling dXSARGS.

dAX;

#dAXMARK

Sets up the ax variable and stack marker variable mark. This is usually handled automatically by xsubpp by calling dXSARGS.

dAXMARK;

#dITEMS

Sets up the items variable. This is usually handled automatically by xsubpp by calling dXSARGS.

dITEMS;

#dMY_CXT

Described in perlxs.

#dMY_CXT_SV

Now a placeholder that declares nothing

dMY_CXT_SV;

#dUNDERBAR

Sets up any variable needed by the UNDERBAR macro. It used to define padoff_du, but it is currently a noop. However, it is strongly advised to still use it for ensuring past and future compatibility.

dUNDERBAR;

#dXSARGS

Sets up stack and mark pointers for an XSUB, calling dSP and dMARK. Sets up the ax and items variables by calling dAX and dITEMS. This is usually handled automatically by xsubpp.

dXSARGS;

#dXSI32

Sets up the ix variable for an XSUB which has aliases. This is usually handled automatically by xsubpp.

dXSI32;

#items

Variable which is setup by xsubpp to indicate the number of items on the stack. See "Variable-length Parameter Lists" in perlxs.

Stack_off_t  items

#ix

Variable which is setup by xsubpp to indicate which of an XSUB's aliases was used to invoke it. See "The ALIAS: Keyword" in perlxs.

I32  ix

#MY_CXT

#MY_CXT_CLONE

#MY_CXT_INIT

#pMY_CXT

#pMY_CXT_

#_pMY_CXT

Described in perlxs.

#RETVAL

Variable which is setup by xsubpp to hold the return value for an XSUB. This is always the proper type for the XSUB. See "The RETVAL Variable" in perlxs.

type  RETVAL

#ST

Used to access elements on the XSUB's stack.

SV*  ST(int ix)

#START_MY_CXT

Described in perlxs.

#THIS

Variable which is setup by xsubpp to designate the object in a C++ XSUB. This is always the proper type for the C++ object. See "CLASS" and "Using XS With C++" in perlxs.

type  THIS

#UNDERBAR

The SV* corresponding to the $_ variable. Works even if there is a lexical $_ in scope.

#XS

Macro to declare an XSUB and its C parameter list. This is handled by xsubpp. It is the same as using the more explicit XS_EXTERNAL macro; the latter is preferred.

#XS_EXTERNAL

Macro to declare an XSUB and its C parameter list explicitly exporting the symbols.

#XS_INTERNAL

Macro to declare an XSUB and its C parameter list without exporting the symbols. This is handled by xsubpp and generally preferable over exporting the XSUB symbols unnecessarily.

#XSPROTO

Macro used by "XS_INTERNAL" and "XS_EXTERNAL" to declare a function prototype. You probably shouldn't be using this directly yourself.

#Undocumented elements

The following functions have been flagged as part of the public API, but are currently undocumented. Use them at your own risk, as the interfaces are subject to change. Functions that are not listed in this document are not intended for public use, and should NOT be used under any circumstances.

If you feel you need to use one of these functions, first send email to perl5-porters@perl.org. It may be that there is a good reason for the function not being documented, and it should be removed from this list; or it may just be that no one has gotten around to documenting it. In the latter case, you will be asked to submit a patch to document the function. Once your patch is accepted, it will indicate that the interface is stable (unless it is explicitly marked otherwise) and usable by you.

clone_params_del  clone_params_new  do_open  do_openn  sv_dup  sv_dup_inc

Next are the API-flagged elements that are considered experimental. Using one of these is even more risky than plain undocumented ones. They are listed here because they should be listed somewhere (so their existence doesn't get lost) and this is the best place for them.

apply_attrs_string        hv_store_flags       thread_locale_init
gv_fetchmethod_pv_flags   leave_adjust_stacks  thread_locale_term
gv_fetchmethod_pvn_flags  newXS_flags          
gv_fetchmethod_sv_flags   savetmps             

Finally are deprecated undocumented API elements. Do not use any for new code; remove all occurrences of all of these from existing code.

There are currently no items of this type

#AUTHORS

Until May 1997, this document was maintained by Jeff Okamoto <okamoto@corp.hp.com>. It is now maintained as part of Perl itself.

With lots of help and suggestions from Dean Roehrich, Malcolm Beattie, Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil Bowers, Matthew Green, Tim Bunce, Spider Boardman, Ulrich Pfeifer, Stephen McCamant, and Gurusamy Sarathy.

API Listing originally by Dean Roehrich <roehrich@cray.com>.

Updated to be autogenerated from comments in the source by Benjamin Stuhl.

#SEE ALSO

config.h, perlapio, perlcall, perlclib, perlembed, perlfilter, perlguts, perlhacktips, perlintern, perlinterp, perliol, perlmroapi, perlreapi, perlreguts, perlxs