Name

fflush — flush a stream

Synopsis

#include <stdio.h>
int fflush( FILE *  stream);

DESCRIPTION

The function fflush() forces a write of all user-space buffered data for the given output or update stream via the stream's underlying write function. The open status of the stream is unaffected.

If the stream argument is NULL, fflush() flushes all open output streams.

For a non-locking counterpart, see unlocked_stdio(3).

RETURN VALUE

Upon successful completion 0 is returned. Otherwise, EOF is returned and the global variable errno is set to indicate the error.

ERRORS

EBADF

Stream is not an open stream, or is not open for writing.

The function fflush() may also fail and set errno for any of the errors specified for the routine write(2).

CONFORMING TO

C89, C99.

NOTES

Note that fflush() only flushes the user space buffers provided by the C library. To ensure that the data is physically stored on disk the kernel buffers must be flushed too, for example, with sync(2) or fsync(2).

SEE ALSO

fsync(2), sync(2), write(2), fclose(3), fopen(3), setbuf(3), unlocked_stdio(3)

COLOPHON

This page is part of release 2.79 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


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This code is derived from software contributed to Berkeley by
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    (#)fflush.3 5.4 (Berkeley) 6/29/91

Converted for Linux, Mon Nov 29 15:22:01 1993, faithcs.unc.edu

Modified 2000-07-22 by Nicolás Lichtmaier <nickdebian.org>
Modified 2001-10-16 by John Levon <mozcompsoc.man.ac.uk>