std::ofstream::is_open
C++98C++11
bool is_open();
Check if file is open
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 rdbuf()->is_open()
Parameters
none
Return Value
true if a file is open and associated with this stream object.
false otherwise.
Example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
// ofstream::is_open
#include // std::cout
#include // std::ofstream
int main () {
std::ofstream ofs;
ofs.open ("test.txt");
if (ofs.is_open())
{
ofs << "lorem ipsum";
std::cout << "Output operation successfully performed\n";
ofs.close();
}
else
{
std::cout << "Error opening file";
}
return 0;
}
Edit & Run
Possible output:
Output operation successfully performed
Data races
Accesses the ofstream object.
Concurrent access to the same stream may introduce data races.
Exception safety