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Returns whether an error flag is set (either failbit or badbit).
Notice that this function does not return the same as member good, but the opposite of member fail.
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::operator bool
operator void*() const;
explicit operator bool() const;
Evaluate stream
Notice that this function does not return the same as member good, but the opposite of member fail.
The function returns a null pointer if at least one of these error flags is set, and some other value otherwise.
The function returns
false if at least one of these error flags is set, and true otherwise.Parameters
noneReturn Value
Example
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Data races
Accesses the stream object.Concurrent access to the same stream object may cause data races.
Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the stream.See also
- basic_ios::fail
- Check whether failbit or badbit is set (public member function)
- basic_ios::operator!
- Evaluate stream (not) (public member function)
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© cplusplus.com, 2000-2025 - All rights reserved - v3.3.4s
Spotted an error? contact us