std::basic_filebuf<CharT,Traits>:: is_open

Returns true if the most recent call to open() succeeded and there has been no call to close() since then.

Parameters

(none)

Return value

true if the associated file is open, false otherwise.

Notes

This function is typically called by std::basic_fstream::is_open() .

Example

#include <fstream>
#include <iostream>
 
int main()
{
    std::ifstream fs("test.txt");
    std::filebuf fb;
    fb.open("test.txt", std::ios_base::in);
    std::cout << std::boolalpha
              << "direct call: " << fb.is_open() << '\n'
              << "through streambuf: " << fs.rdbuf()->is_open() << '\n'
              << "through fstream: " << fs.is_open() << '\n';
}

direct call: true
through streambuf: true
through fstream: true

See also