fflush.c revision 16586 
1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)fflush.c	8.1 (Berkeley) 6/4/93";
40#endif
41static const char rcsid[] =
42		"$Id$";
43#endif /* LIBC_SCCS and not lint */
44
45#include <errno.h>
46#include <stdio.h>
47#include "local.h"
48#ifdef _THREAD_SAFE
49#include <pthread.h>
50#include "pthread_private.h"
51#endif
52
53/* Flush a single file, or (if fp is NULL) all files.  */
54int
55fflush(fp)
56	register FILE *fp;
57{
58	int retval;
59
60	if (fp == NULL)
61		return (_fwalk(__sflush));
62#ifdef _THREAD_SAFE
63	_thread_flockfile(fp,__FILE__,__LINE__);
64#endif
65	if ((fp->_flags & (__SWR | __SRW)) == 0) {
66		errno = EBADF;
67		retval = EOF;
68	} else {
69		retval = __sflush(fp);
70	}
71#ifdef _THREAD_SAFE
72	_thread_funlockfile(fp);
73#endif
74	return (retval);
75}
76
77int
78__sflush(fp)
79	register FILE *fp;
80{
81	register unsigned char *p;
82	register int n, t;
83
84	t = fp->_flags;
85	if ((t & __SWR) == 0)
86		return (0);
87
88	if ((p = fp->_bf._base) == NULL)
89		return (0);
90
91	n = fp->_p - p;		/* write this much */
92
93	/*
94	 * Set these immediately to avoid problems with longjmp and to allow
95	 * exchange buffering (via setvbuf) in user write function.
96	 */
97	fp->_p = p;
98	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
99
100	for (; n > 0; n -= t, p += t) {
101		t = (*fp->_write)(fp->_cookie, (char *)p, n);
102		if (t <= 0) {
103			fp->_flags |= __SERR;
104			return (EOF);
105		}
106	}
107	return (0);
108}
109