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fflush(3) - fflush, fflush - flush a stream - man 3 fflush

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



NAME
       fflush - flush(8,n) a stream

SYNOPSIS
       #include <stdio.h>

       int fflush(FILE *stream);

DESCRIPTION
       The  function fflush forces a write(1,2) of all user-space buffered data for
       the given output or update(7,n) stream via  the  stream's  underlying  write(1,2)
       function.  The open(2,3,n) status of the stream is unaffected.

       If the stream argument is NULL, fflush flushes all open(2,3,n) 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(7,n,1 builtins) to indicate the error.

ERRORS
       EBADF  Stream is not an open(2,3,n) stream, or is not open(2,3,n) for writing.

       The  function  fflush may also fail and set(7,n,1 builtins) errno for any of the errors
       specified for the routine write(1,2)(2).

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, e.g. with sync(1,2,8)(2) or fsync(2).

CONFORMING TO
       The function fflush() conforms to ANSI X3.159-1989 (``ANSI C'').

SEE ALSO
       fsync(2),   sync(1,2,8)(2),   write(1,2)(2),   fclose(3),   fopen(3),    setbuf(3),
       unlocked_stdio(3)



BSD MANPAGE                       1993-11-29                         FFLUSH(3)

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