fflush.c revision 1573 
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)
38static char sccsid[] = "@(#)fflush.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#include <errno.h>
42#include <stdio.h>
43#include "local.h"
44
45/* Flush a single file, or (if fp is NULL) all files.  */
46fflush(fp)
47	register FILE *fp;
48{
49
50	if (fp == NULL)
51		return (_fwalk(__sflush));
52	if ((fp->_flags & (__SWR | __SRW)) == 0) {
53		errno = EBADF;
54		return (EOF);
55	}
56	return (__sflush(fp));
57}
58
59__sflush(fp)
60	register FILE *fp;
61{
62	register unsigned char *p;
63	register int n, t;
64
65	t = fp->_flags;
66	if ((t & __SWR) == 0)
67		return (0);
68
69	if ((p = fp->_bf._base) == NULL)
70		return (0);
71
72	n = fp->_p - p;		/* write this much */
73
74	/*
75	 * Set these immediately to avoid problems with longjmp and to allow
76	 * exchange buffering (via setvbuf) in user write function.
77	 */
78	fp->_p = p;
79	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
80
81	for (; n > 0; n -= t, p += t) {
82		t = (*fp->_write)(fp->_cookie, (char *)p, n);
83		if (t <= 0) {
84			fp->_flags |= __SERR;
85			return (EOF);
86		}
87	}
88	return (0);
89}
90