xref: /netbsd-src/lib/libc/stdio/fwrite.c (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1 /*	$NetBSD: fwrite.c,v 1.6 1997/07/13 20:15:10 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 1.6 1997/07/13 20:15:10 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 
52 /*
53  * Write `count' objects (each size `size') from memory to the given file.
54  * Return the number of whole objects written.
55  */
56 size_t
57 fwrite(buf, size, count, fp)
58 	const void *buf;
59 	size_t size, count;
60 	FILE *fp;
61 {
62 	size_t n;
63 	struct __suio uio;
64 	struct __siov iov;
65 
66 	iov.iov_base = (void *)buf;
67 	uio.uio_resid = iov.iov_len = n = count * size;
68 	uio.uio_iov = &iov;
69 	uio.uio_iovcnt = 1;
70 
71 	/*
72 	 * The usual case is success (__sfvwrite returns 0);
73 	 * skip the divide if this happens, since divides are
74 	 * generally slow and since this occurs whenever size==0.
75 	 */
76 	if (__sfvwrite(fp, &uio) == 0)
77 		return (count);
78 	return ((n - uio.uio_resid) / size);
79 }
80