@node fflush, stdio
@subheading Syntax

@example
#include <stdio.h>

int fflush(FILE *file);
@end example

@subheading Description

If @var{file} is not a @code{NULL} pointer, this function causes any
unwritten buffered data to be written out to the given @var{file}.  This
is useful in cases where the output is line buffered and you want to
write a partial line.

If @var{file} is a @code{NULL} pointer, @code{fflush} writes any
buffered output to all files opened for output.

Note that @code{fflush} has no effect for streams opened for reading
only.  Also note that the operating system can further buffer/cache
writes to disk files; a call to @code{fsync} (@pxref{fsync}) or
@code{sync} (@pxref{sync}) is typically required to actually deliver
data to the file(s).

@subheading Return Value

Zero on success, -1 on error.  When called with a @code{NULL} pointer,
-1 will be returned if an error happened while flushing some of the
streams (but @code{fflush} will still try to flush all the rest before
it returns).

@subheading Portability

@portability ansi, posix

@subheading Example

@example
printf("Enter value : ");
fflush(stdout);
scanf(result);
@end example