1 /* $OpenBSD: fflush.c,v 1.5 2005/08/08 08:05:36 espie Exp $ */
2 /*-
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Chris Torek.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <errno.h>
35 #include <stdio.h>
36 #include "local.h"
37
38 /* Flush a single file, or (if fp is NULL) all files. */
39 int
fflush(FILE * fp)40 fflush(FILE *fp)
41 {
42
43 if (fp == NULL)
44 return (_fwalk(__sflush));
45 if ((fp->_flags & (__SWR | __SRW)) == 0) {
46 errno = EBADF;
47 return (EOF);
48 }
49 return (__sflush(fp));
50 }
51
52 int
__sflush(FILE * fp)53 __sflush(FILE *fp)
54 {
55 unsigned char *p;
56 int n, t;
57
58 t = fp->_flags;
59 if ((t & __SWR) == 0)
60 return (0);
61
62 if ((p = fp->_bf._base) == NULL)
63 return (0);
64
65 n = fp->_p - p; /* write this much */
66
67 /*
68 * Set these immediately to avoid problems with longjmp and to allow
69 * exchange buffering (via setvbuf) in user write function.
70 */
71 fp->_p = p;
72 fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
73
74 for (; n > 0; n -= t, p += t) {
75 t = (*fp->_write)(fp->_cookie, (char *)p, n);
76 if (t <= 0) {
77 fp->_flags |= __SERR;
78 return (EOF);
79 }
80 }
81 return (0);
82 }
83