fflush.c revision 82838 
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  "$FreeBSD: head/lib/libc/stdio/fflush.c 82838 2001-09-03 02:24:37Z ache $";
43#endif /* LIBC_SCCS and not lint */
44
45#include "namespace.h"
46#include <errno.h>
47#include <stdio.h>
48#include "un-namespace.h"
49#include "libc_private.h"
50#include "local.h"
51
52static int	sflush_locked(FILE *);
53
54/*
55 * Flush a single file, or (if fp is NULL) all files.
56 * MT-safe version
57 */
58int
59fflush(FILE *fp)
60{
61	int retval;
62
63	if (fp == NULL)
64		return (_fwalk(sflush_locked));
65	FLOCKFILE(fp);
66	if ((fp->_flags & (__SWR | __SRW)) == 0) {
67		errno = EBADF;
68		retval = EOF;
69	} else
70		retval = __sflush(fp);
71	FUNLOCKFILE(fp);
72	return (retval);
73}
74
75/*
76 * Flush a single file, or (if fp is NULL) all files.
77 * Non-MT-safe version
78 */
79int
80__fflush(FILE *fp)
81{
82	int retval;
83
84	if (fp == NULL)
85		return (_fwalk(sflush_locked));
86	if ((fp->_flags & (__SWR | __SRW)) == 0) {
87		errno = EBADF;
88		retval = EOF;
89	} else
90		retval = __sflush(fp);
91	return (retval);
92}
93
94int
95__sflush(FILE *fp)
96{
97	unsigned char *p;
98	int n, t;
99
100	t = fp->_flags;
101	if ((t & __SWR) == 0)
102		return (0);
103
104	if ((p = fp->_bf._base) == NULL)
105		return (0);
106
107	n = fp->_p - p;		/* write this much */
108
109	/*
110	 * Set these immediately to avoid problems with longjmp and to allow
111	 * exchange buffering (via setvbuf) in user write function.
112	 */
113	fp->_p = p;
114	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
115
116	for (; n > 0; n -= t, p += t) {
117		t = _swrite(fp, (char *)p, n);
118		if (t <= 0) {
119			fp->_flags |= __SERR;
120			return (EOF);
121		}
122	}
123	return (0);
124}
125
126static int
127sflush_locked(FILE *fp)
128{
129	int	ret;
130
131	FLOCKFILE(fp);
132	ret = __sflush(fp);
133	FUNLOCKFILE(fp);
134	return (ret);
135}
136