fflush.c revision 35129 
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: fflush.c,v 1.5 1997/02/22 15:01:50 peter Exp $";
43#endif /* LIBC_SCCS and not lint */
44
45#include <errno.h>
46#include <stdio.h>
47#include "local.h"
48#include "libc_private.h"
49
50/* Flush a single file, or (if fp is NULL) all files.  */
51int
52fflush(fp)
53	register FILE *fp;
54{
55	int retval;
56
57	if (fp == NULL)
58		return (_fwalk(__sflush));
59	FLOCKFILE(fp);
60	if ((fp->_flags & (__SWR | __SRW)) == 0) {
61		errno = EBADF;
62		retval = EOF;
63	} else {
64		retval = __sflush(fp);
65	}
66	FUNLOCKFILE(fp);
67	return (retval);
68}
69
70int
71__sflush(fp)
72	register FILE *fp;
73{
74	register unsigned char *p;
75	register int n, t;
76
77	t = fp->_flags;
78	if ((t & __SWR) == 0)
79		return (0);
80
81	if ((p = fp->_bf._base) == NULL)
82		return (0);
83
84	n = fp->_p - p;		/* write this much */
85
86	/*
87	 * Set these immediately to avoid problems with longjmp and to allow
88	 * exchange buffering (via setvbuf) in user write function.
89	 */
90	fp->_p = p;
91	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
92
93	for (; n > 0; n -= t, p += t) {
94		t = (*fp->_write)(fp->_cookie, (char *)p, n);
95		if (t <= 0) {
96			fp->_flags |= __SERR;
97			return (EOF);
98		}
99	}
100	return (0);
101}
102