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fflush.c revision 1.11 
      1 /*	$NetBSD: fflush.c,v 1.11 1998/02/03 18:41:07 perry 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 1.11 1998/02/03 18:41:07 perry 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 #ifdef _REENT
     54 extern rwlock_t __sfp_lock;
     55 #endif
     56 
     57 /* Flush a single file, or (if fp is NULL) all files.  */
     58 int
     59 fflush(fp)
     60 	FILE *fp;
     61 {
     62 	int r;
     63 
     64 	if (fp == NULL) {
     65 		rwlock_rdlock(&__sfp_lock);
     66 		r = _fwalk(__sflush);
     67 		rwlock_unlock(&__sfp_lock);
     68 		return r;
     69 	}
     70 
     71 	FLOCKFILE(fp);
     72 	if ((fp->_flags & (__SWR | __SRW)) == 0) {
     73 		errno = EBADF;
     74 		r = EOF;
     75 	} else {
     76 		r = __sflush(fp);
     77 	}
     78 	FUNLOCKFILE(fp);
     79 	return r;
     80 }
     81 
     82 int
     83 __sflush(fp)
     84 	FILE *fp;
     85 {
     86 	unsigned char *p;
     87 	int n, t;
     88 
     89 	t = fp->_flags;
     90 	if ((t & __SWR) == 0)
     91 		return (0);
     92 
     93 	if ((p = fp->_bf._base) == NULL)
     94 		return (0);
     95 
     96 	n = fp->_p - p;		/* write this much */
     97 
     98 	/*
     99 	 * Set these immediately to avoid problems with longjmp and to allow
    100 	 * exchange buffering (via setvbuf) in user write function.
    101 	 */
    102 	fp->_p = p;
    103 	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
    104 
    105 	for (; n > 0; n -= t, p += t) {
    106 		t = (*fp->_write)(fp->_cookie, (char *)p, n);
    107 		if (t <= 0) {
    108 			fp->_flags |= __SERR;
    109 			return (EOF);
    110 		}
    111 	}
    112 	return (0);
    113 }
    114