xref: /netbsd-src/lib/libc/stdio/fwrite.c (revision dc306354b0b29af51801a7632f1e95265a68cd81)
1 /*	$NetBSD: fwrite.c,v 1.8 1998/11/15 17:19:53 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Chris Torek.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 #if 0
42 static char sccsid[] = "@(#)fwrite.c	8.1 (Berkeley) 6/4/93";
43 #else
44 __RCSID("$NetBSD: fwrite.c,v 1.8 1998/11/15 17:19:53 christos Exp $");
45 #endif
46 #endif /* LIBC_SCCS and not lint */
47 
48 #include <stdio.h>
49 #include "local.h"
50 #include "fvwrite.h"
51 #include "reentrant.h"
52 
53 /*
54  * Write `count' objects (each size `size') from memory to the given file.
55  * Return the number of whole objects written.
56  */
57 size_t
58 fwrite(buf, size, count, fp)
59 	const void *buf;
60 	size_t size, count;
61 	FILE *fp;
62 {
63 	size_t n;
64 	struct __suio uio;
65 	struct __siov iov;
66 
67 	/* LINTED we don't play with buf */
68 	iov.iov_base = (void *)buf;
69 	uio.uio_resid = iov.iov_len = n = count * size;
70 	uio.uio_iov = &iov;
71 	uio.uio_iovcnt = 1;
72 
73 	/*
74 	 * The usual case is success (__sfvwrite returns 0);
75 	 * skip the divide if this happens, since divides are
76 	 * generally slow and since this occurs whenever size==0.
77 	 */
78 	FLOCKFILE(fp);
79 	if (__sfvwrite(fp, &uio) != 0)
80 		count = ((n - uio.uio_resid) / size);
81 	FUNLOCKFILE(fp);
82 	return (count);
83 }
84