xref: /freebsd/lib/libc/stdio/fwrite.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
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  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)fwrite.c	8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include "namespace.h"
40 #include <stdio.h>
41 #include "un-namespace.h"
42 #include "local.h"
43 #include "fvwrite.h"
44 #include "libc_private.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 * __restrict buf;
53 	size_t size, count;
54 	FILE * __restrict 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 	FLOCKFILE(fp);
66 	ORIENT(fp, -1);
67 	/*
68 	 * The usual case is success (__sfvwrite returns 0);
69 	 * skip the divide if this happens, since divides are
70 	 * generally slow and since this occurs whenever size==0.
71 	 */
72 	if (__sfvwrite(fp, &uio) != 0)
73 	    count = (n - uio.uio_resid) / size;
74 	FUNLOCKFILE(fp);
75 	return (count);
76 }
77