std::basic_filebuf<CharT,Traits>::is_open (3) - Linux Man Pages

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

NAME

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

Synopsis


bool is_open() const;


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


// Run this code


  #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';
  }

Output:


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

See also


      opens a file and configures it as the associated character sequence
open (public member function)
      flushes the put area buffer and closes the associated file
close (public member function)