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Indicates whether a file is open.
bool is_open( ) const;
Return Value
true if the file is open, false otherwise.
Remarks
The member function returns rdbuf -> is_open.
Example
// basic_ofstream_is_open.cpp
// compile with: /EHsc
#include <fstream>
#include <iostream>
int main( ) 
{
   using namespace std;
   ifstream file;
   // Open and close with a basic_filebuf
   file.rdbuf( )->open( "basic_ofstream_is_open.txt", ios::in );
   file.close( );
   if (file.is_open())
      cout << "it's open" << endl;
   else
      cout << "it's closed" << endl;
}
Output
it's closed
Requirements
Header: <fstream>
Namespace: std