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FFLUSH(3)		   Linux Programmer's Manual		     FFLUSH(3)

NAME
       fflush -	flush a	stream

SYNOPSIS
       #include	<stdio.h>

       int fflush(FILE *stream);

DESCRIPTION
       For  output streams, fflush() forces a write of all user-space buffered
       data for	the given output or update stream via the stream's  underlying
       write function.	For input streams, fflush() discards any buffered data
       that has	been fetched from the underlying file, but has not  been  con-
       sumed by	the application.  The open status of the stream	is unaffected.

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

       For a nonlocking	counterpart, see unlocked_stdio(3).

RETURN VALUE
       Upon successful completion 0 is returned.  Otherwise, EOF  is  returned
       and 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 write(2).

ATTRIBUTES
   Multithreading (see pthreads(7))
       The fflush() function is	thread-safe.

CONFORMING TO
       C89, C99, POSIX.1-2001, POSIX.1-2008.

       The standards do	not specify the	 behavior  for	input  streams.	  Most
       other implementations behave the	same as	Linux.

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),   un-
       locked_stdio(3)

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest	  version     of     this    page,    can    be	   found    at
       http://www.kernel.org/doc/man-pages/.

GNU				  2013-07-15			     FFLUSH(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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