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Input stream class to operate on files.
Objects of this class maintain a basic_filebuf object as their internal stream buffer, which performs input/output operations on the file they are associated with (if any).
File streams are associated with files either on construction, or by calling member open.
Apart from the internal file stream buffer, objects of these classes keep a set of internal fields inherited from ios_base, basic_ios and basic_istream:
These member types are inherited from its base classes basic_istream and ios_base:
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
<fstream>
class templates
classes
basic_ifstream
- basic_ifstream::basic_ifstream
public member functions
non-member overloads
-
swap (basic_ifstream)C++11
-
class template
<fstream>
std::basic_ifstream
template < class charT, class traits = char_traits<charT> > class basic_ifstream;
Input file stream
- ios_base
- basic_ios
- basic_istream
- basic_ifstream
Input stream class to operate on files.
Objects of this class maintain a basic_filebuf object as their internal stream buffer, which performs input/output operations on the file they are associated with (if any).
File streams are associated with files either on construction, or by calling member open.
Apart from the internal file stream buffer, objects of these classes keep a set of internal fields inherited from ios_base, basic_ios and basic_istream:
field | member functions | description | |
---|---|---|---|
Formatting | format flags | flags setf unsetf | A set of internal flags that affect how certain input/output operations are interpreted or generated. See member type fmtflags. |
field width | width | Width of the next formatted element to insert. | |
display precision | precision | Decimal precision for the next floating-point value inserted. | |
locale | getloc imbue | The locale object used by the function for formatted input/output operations affected by localization properties. | |
fill character | fill | Character to pad a formatted field up to the field width (width). | |
State | error state | rdstate setstate clear | The current error state of the stream. Individual values may be obtained by calling good, eof, fail and bad. See member type iostate. |
exception mask | exceptions | The state flags for which a failure exception is thrown. See member type iostate. | |
Other | callback stack | register_callback | Stack of pointers to functions that are called when certain events occur. |
extensible arrays | iword pword xalloc | Internal arrays to store objects of type long and void* . | |
tied stream | tie | Pointer to output stream that is flushed before each i/o operation on this stream. | |
stream buffer | rdbuf | Pointer to the associated basic_streambuf object, which is charge of all input/output operations. | |
character count | gcount | Count of characters read by last unformatted input operation (input streams only). |
Template parameters
- charT
- Character type.
This shall be a non-array POD type.
Aliased as member type basic_ifstream::char_type. - traits
- Character traits class that defines essential properties of the characters used by stream object (see char_traits).
traits::char_type shall be the same as charT.
Aliased as member type basic_ifstream::traits_type.
Template instantiations
- ifstream
- Input file stream class (class)
- wifstream
- Input file stream (wide) (class)
Member types
The class declares the following member types:member type | definition | notes |
---|---|---|
char_type | The first template parameter (charT) | |
traits_type | The second template parameter (traits) | defaults to: char_traits<charT> |
int_type | traits_type::int_type | |
pos_type | traits_type::pos_type | generally, the same as streampos |
off_type | traits_type::off_type | generally, the same as streamoff |
These member types are inherited from its base classes basic_istream and ios_base:
- event
- Type to indicate event type (public member type)
- event_callback
- Event callback function type (public member type)
- failure
- Base class for stream exceptions (public member class)
- fmtflags
- Type for stream format flags (public member type)
- Init
- Initialize standard stream objects (public member class)
- iostate
- Type for stream state flags (public member type)
- openmode
- Type for stream opening mode flags (public member type)
- seekdir
- Type for stream seeking direction flag (public member type)
- sentry
- Prepare stream for input (public member class)
Public member functions
- (constructor)
- Construct object (public member function)
- open
- Open file (public member function)
- is_open
- Check if file is open (public member function)
- close
- Close file (public member function)
- rdbuf
- Get stream buffer (public member function)
- operator=
- Move assignment (public member function)
- swap
- Swap internals (public member function)
Public member functions inherited from basic_istream
- operator>>
- Extract formatted input (public member function)
- gcount
- Get character count (public member function)
- get
- Get characters (public member function)
- getline
- Get line (public member function)
- ignore
- Extract and discard characters (public member function)
- peek
- Peek next character (public member function)
- read
- Read block of data (public member function)
- readsome
- Read data available in buffer (public member function)
- putback
- Put character back (public member function)
- unget
- Unget character (public member function)
- tellg
- Get position in input sequence (public member function)
- seekg
- Set position in input sequence (public member function)
- sync
- Synchronize input buffer (public member function)
Public member functions inherited from basic_ios
- good
- Check whether state of stream is good (public member function)
- eof
- Check whether eofbit is set (public member function)
- fail
- Check whether failbit or badbit is set (public member function)
- bad
- Check whether badbit is set (public member function)
- operator!
- Evaluate stream (not) (public member function)
- operator bool
- Evaluate stream (public member function)
- rdstate
- Get error state flags (public member function)
- setstate
- Set error state flag (public member function)
- clear
- Set error state flags (public member function)
- copyfmt
- Copy formatting information (public member function)
- fill
- Get/set fill character (public member function)
- exceptions
- Get/set exceptions mask (public member function)
- imbue
- Imbue locale (public member function)
- tie
- Get/set tied stream (public member function)
- rdbuf
- Get/set stream buffer (public member function)
- narrow
- Narrow character (public member function)
- widen
- Widen character (public member function)
Public member functions inherited from ios_base
- flags
- Get/set format flags (public member function)
- setf
- Set specific format flags (public member function)
- unsetf
- Clear specific format flags (public member function)
- precision
- Get/Set floating-point decimal precision (public member function)
- width
- Get/set field width (public member function)
- imbue
- Imbue locale (public member function)
- getloc
- Get current locale (public member function)
- xalloc
- Get new index for extensible array [static] (public static member function)
- iword
- Get integer element of extensible array (public member function)
- pword
- Get pointer element of extensible array (public member function)
- register_callback
- Register event callback function (public member function)
- sync_with_stdio
- Toggle synchronization with cstdio streams [static] (public static member function)
Non-member function overloads
- swap
- Swap input file streams (function template)
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Spotted an error? contact us