xref: /netbsd-src/lib/libc/stdio/fwrite.c (revision d9158b13b5dfe46201430699a3f7a235ecf28df3)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * 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 /*static char *sccsid = "from: @(#)fwrite.c	5.5 (Berkeley) 2/24/91";*/
39 static char *rcsid = "$Id: fwrite.c,v 1.4 1993/10/04 18:51:13 jtc Exp $";
40 #endif /* LIBC_SCCS and not lint */
41 
42 #include <stdio.h>
43 #include "local.h"
44 #include "fvwrite.h"
45 
46 /*
47  * Write `count' objects (each size `size') from memory to the given file.
48  * Return the number of whole objects written.
49  */
50 size_t
51 fwrite(buf, size, count, fp)
52 	const void *buf;
53 	size_t size, count;
54 	FILE *fp;
55 {
56 	size_t n;
57 	struct __suio uio;
58 	struct __siov iov;
59 
60 	iov.iov_base = (void *)buf;
61 	uio.uio_resid = iov.iov_len = n = count * size;
62 	uio.uio_iov = &iov;
63 	uio.uio_iovcnt = 1;
64 
65 	/*
66 	 * The usual case is success (__sfvwrite returns 0);
67 	 * skip the divide if this happens, since divides are
68 	 * generally slow and since this occurs whenever size==0.
69 	 */
70 	if (__sfvwrite(fp, &uio) == 0)
71 		return (count);
72 	return ((n - uio.uio_resid) / size);
73 }
74