io:clear

Syntax:

    #include <fstream>
    void clear( iostate flags = ios::goodbit );

The function clear() does two things:

• it clears all io_stream_state_flags associated with the current stream,
• and sets the flags denoted by flags

The flags argument defaults to ios::goodbit, which means that by default, all flags will be cleared and ios::goodbit will be set. Example code: For example, the following code uses the clear() function to reset the flags of an output file stream, after an attempt is made to read from that output stream:

   fstream outputFile( "output.txt", fstream::out );
 
   // try to read from the output stream; this shouldn't work
   int val;
   outputFile >> val;
   if( outputFile.fail() ) {
     cout << "Error reading from the output stream" << endl;
     // reset the flags associated with the stream
     outputFile.clear();
   }

   for( int i = 0; i < 10; i++ ) {
     outputFile << i << " ";
   }
   outputFile << endl;

Related Topics: eof, fail, good, rdstate