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fflush.c revision 1.9 
      1 /*	$NetBSD: fflush.c,v 1.9 1998/01/19 07:38:42 jtc Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Chris Torek.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 #if 0
     42 static char sccsid[] = "@(#)fflush.c	8.1 (Berkeley) 6/4/93";
     43 #else
     44 __RCSID("$NetBSD: fflush.c,v 1.9 1998/01/19 07:38:42 jtc Exp $");
     45 #endif
     46 #endif /* LIBC_SCCS and not lint */
     47 
     48 #include <errno.h>
     49 #include <stdio.h>
     50 #include "local.h"
     51 #include "reentrant.h"
     52 
     53 /* Flush a single file, or (if fp is NULL) all files.  */
     54 int
     55 fflush(fp)
     56 	register FILE *fp;
     57 {
     58 	int r;
     59 
     60 	if (fp == NULL)
     61 		return (_fwalk(__sflush));
     62 
     63 	FLOCKFILE(fp);
     64 	if ((fp->_flags & (__SWR | __SRW)) == 0) {
     65 		errno = EBADF;
     66 		r = EOF;
     67 	} else {
     68 		r = __sflush(fp);
     69 	}
     70 	FUNLOCKFILE(fp);
     71 	return r;
     72 }
     73 
     74 int
     75 __sflush(fp)
     76 	register FILE *fp;
     77 {
     78 	register unsigned char *p;
     79 	register int n, t;
     80 
     81 	t = fp->_flags;
     82 	if ((t & __SWR) == 0)
     83 		return (0);
     84 
     85 	if ((p = fp->_bf._base) == NULL)
     86 		return (0);
     87 
     88 	n = fp->_p - p;		/* write this much */
     89 
     90 	/*
     91 	 * Set these immediately to avoid problems with longjmp and to allow
     92 	 * exchange buffering (via setvbuf) in user write function.
     93 	 */
     94 	fp->_p = p;
     95 	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
     96 
     97 	for (; n > 0; n -= t, p += t) {
     98 		t = (*fp->_write)(fp->_cookie, (char *)p, n);
     99 		if (t <= 0) {
    100 			fp->_flags |= __SERR;
    101 			return (EOF);
    102 		}
    103 	}
    104 	return (0);
    105 }
    106