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The first form (1) returns the current exception mask for the stream.
The second form (2) sets a new exception mask for the stream and clears the stream's error state flags (as if member
The exception mask is an internal value kept by all stream objects specifying for which state flags an exception of member type failure (or some derived type) is thrown when set. This mask is an object of member type iostate, which is a value formed by any combination of the following member constants:
eofbit, failbit and badbit are member constants with implementation-defined values that can be combined (as if with the bitwise OR operator), so that the stream throws when any of the selected error state flags is set.
goodbit is zero, indicating that no exceptions shall be thrown when an error state flags is set.
All streams have goodbit by default (they do not throw exceptions due to error state flags being set).
Concurrent access to the same stream object may cause data races.
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>
<ios>
types
manipulators
other functions
-
iostream_categoryC++11
-
basic_ios
- basic_ios::~basic_ios
- basic_ios::basic_ios
public members
- basic_ios::bad
- basic_ios::clear
- basic_ios::copyfmt
- basic_ios::eof
- basic_ios::exceptions
- basic_ios::fail
- basic_ios::fill
- basic_ios::good
- basic_ios::imbue
- basic_ios::narrow
- basic_ios::operator bool
- basic_ios::operator!
- basic_ios::rdbuf
- basic_ios::rdstate
- basic_ios::setstate
- basic_ios::tie
- basic_ios::widen
protected members
- basic_ios::init
-
basic_ios::moveC++11
-
basic_ios::set_rdbufC++11
-
basic_ios::swapC++11
public member function
<ios> <iostream>
std::basic_ios::exceptions
| get (1) | iostate exceptions() const; |
|---|---|
| set (2) | void exceptions (iostate except); |
Get/set exceptions mask
The second form (2) sets a new exception mask for the stream and clears the stream's error state flags (as if member
clear() was called).The exception mask is an internal value kept by all stream objects specifying for which state flags an exception of member type failure (or some derived type) is thrown when set. This mask is an object of member type iostate, which is a value formed by any combination of the following member constants:
| iostate value (member constants) | indicates | functions to check state flags | ||||
|---|---|---|---|---|---|---|
| good() | eof() | fail() | bad() | rdstate() | ||
| goodbit | No errors (zero value iostate) | true | false | false | false | goodbit |
| eofbit | End-of-File reached on input operation | false | true | false | false | eofbit |
| failbit | Logical error on i/o operation | false | false | true | false | failbit |
| badbit | Read/writing error on i/o operation | false | false | true | true | badbit |
goodbit is zero, indicating that no exceptions shall be thrown when an error state flags is set.
All streams have goodbit by default (they do not throw exceptions due to error state flags being set).
Parameters
- except
- A bitmask value of member type iostate formed by a combination of error state flag bits to be set (badbit, eofbit and/or failbit), or set to goodbit (or zero).
Return Value
The first form (1) returns a bitmask of member type iostate representing the existing exception mask before the call to this member function.Example
|
|
Data races
Accesses (1) or modifies (2) the stream object.Concurrent access to the same stream object may cause data races.
Exception safety
Basic guarantee: if an exception is thrown, the stream is in a valid state.See also
- basic_ios::rdstate
- Get error state flags (public member function)
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Spotted an error? contact us