public member function

std::ofstream::is_open

bool is_open();

bool is_open() const;

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

// ofstream::is_open
#include <iostream>     // std::cout
#include <fstream>      // 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;
}