rewind()

Rewind a file stream to the beginning of the file

Synopsis:

#include <stdio.h>

void rewind( FILE *fp );

Arguments:

fp: The file stream that you want to rewind.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The rewind() function rewinds the file stream specified by fp to the beginning of the file. It's equivalent to calling fseek() like this:

fseek( fp, 0L, SEEK_SET );

except that the error indicator for the stream is cleared.

Examples:

This example shows how you might implement a two-pass assembler:

#include <stdio.h>
#include <stdlib.h>

void assemble_pass( FILE *fp, int passno )
{
    printf( "Pass %d\n", passno );
    
    /* Do more work on the fp */
    switch( passno ) {
    case 1:
        /* do the first-pass work */
        break;
        
    case 2:
        /* do the second-pass work */
        break;
    
    default:
        break;
    }
}

int main( void )
{
    FILE *fp;

    fp = fopen( "program.s", "r" );
    if( fp != NULL ) {
        assemble_pass( fp, 1 );
        rewind( fp );

        assemble_pass( fp, 2 );
        fclose( fp );
        
        return EXIT_SUCCESS;
    }

    puts( "Error opening program.s" );

    return EXIT_FAILURE;
}

Classification:

ANSI, POSIX 1003.1

Safety:
Cancellation point	Yes
Interrupt handler	No
Signal handler	No
Thread	Yes

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