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/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
FUNCTION
<<fflush>>---flush buffered file output
INDEX
fflush
ANSI_SYNOPSIS
#include <stdio.h>
int fflush(FILE *<[fp]>);
TRAD_SYNOPSIS
#include <stdio.h>
int fflush(<[fp]>)
FILE *<[fp]>;
DESCRIPTION
The <<stdio>> output functions can buffer output before delivering it
to the host system, in order to minimize the overhead of system calls.
Use <<fflush>> to deliver any such pending output (for the file
or stream identified by <[fp]>) to the host system.
If <[fp]> is <<NULL>>, <<fflush>> delivers pending output from all
open files.
RETURNS
<<fflush>> returns <<0>> unless it encounters a write error; in that
situation, it returns <<EOF>>.
PORTABILITY
ANSI C requires <<fflush>>.
No supporting OS subroutines are required.
*/
#include <stdio.h>
#include "local.h"
/* Flush a single file, or (if fp is NULL) all files. */
int
_DEFUN (fflush, (fp),
register FILE * fp)
{
register unsigned char *p;
register int n, t;
if (fp == NULL)
return _fwalk (_REENT, fflush);
CHECK_INIT (fp);
t = fp->_flags;
if ((t & __SWR) == 0 || (p = fp->_bf._base) == NULL)
return 0;
n = fp->_p - p; /* write this much */
/*
* Set these immediately to avoid problems with longjmp
* and to allow exchange buffering (via setvbuf) in user
* write function.
*/
fp->_p = p;
fp->_w = t & (__SLBF | __SNBF) ? 0 : fp->_bf._size;
while (n > 0)
{
t = (*fp->_write) (fp->_cookie, (char *) p, n);
if (t <= 0)
{
fp->_flags |= __SERR;
return EOF;
}
p += t;
n -= t;
}
return 0;
}
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