ofstream::is_open
bool is_open ( );
ofstream
  cplusplus.com  

Check if a file has been opened.
  Checks if the stream is currently associated with a valid file buffer.

Parameters.

none
 

Return Value.
  If a file has successfully been opened (i.e. the stream is associated with a valid file buffer) the member function returns true,
  otherwise false is returned.

Example.

// ofstream::is_open
#include <iostream>
#include <fstream>
using namespace std;

int main () {

  ofstream outfile;
  outfile.open ("test.txt");
  if (outfile.is_open())
  {
    outfile << "Output operation successfully performed\n";
    outfile.close();
  }
  else
  {
    cout << "Error opening file";
  }
  return 0;
}
This example uses is_open to check if the file has successfully been opened, if so writes a sentence to the file, otherwise shows an error message on the standard output.

Basic template member declaration ( basic_ofstream<charT,traits> ):
bool is_open ();

See also.
  open
  ofstream class


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