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fflush()

Flush the buffers for a stream

Synopsis:

#include <stdio.h>

int fflush( FILE* fp );

Arguments:

fp: NULL, or the stream whose buffers you want to flush.

Library:

libc

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

If the stream specified by fp is open for output or update, the fflush() function causes any buffered (see setvbuf()) but unwritten data to be written to the file descriptor associated with the stream (see fileno()).

If the file specified by fp is open for input or update, the fflush() function undoes the effect of any preceding ungetc operation on the stream.

If fp is NULL, all open streams are flushed.

Returns:

0 for success, or EOF if an error occurs (errno is set).

Examples:

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

int main( void )
{
    printf( "Press Enter to continue..." );
    fflush( stdout );
    getchar();

    return EXIT_SUCCESS;
}

Classification:

ANSI, POSIX 1003.1

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