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Returns whether the stream is currently associated to a file.
Streams can be associated to files by a successful call to member open or directly on construction, and disassociated by calling close or on destruction.
The file association of a stream is kept by its internal stream buffer:
Internally, the function calls
Concurrent access to the same stream may introduce 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>
<fstream>
class templates
classes
basic_ifstream
- basic_ifstream::basic_ifstream
public member functions
non-member overloads
-
swap (basic_ifstream)C++11
-
- Reference
- <fstream>
- basic_ifstream
- is_open
public member function
<fstream>
std::basic_ifstream::is_open
bool is_open();
bool is_open() const;
Check if file is open
Streams can be associated to files by a successful call to member open or directly on construction, and disassociated by calling close or on destruction.
The file association of a stream is kept by its internal stream buffer:
Internally, the function calls
rdbuf()->is_open()
Parameters
noneReturn Value
true
if a file is open and associated with this stream object.false
otherwise.Example
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Data races
Accesses the basic_ifstream object.Concurrent access to the same stream may introduce data races.
Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the stream.See also
- basic_ifstream::open
- Open file (public member function)
- basic_ifstream::close
- Close file (public member function)
- basic_filebuf::is_open
- Check if file is open (public member function)
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Spotted an error? contact us