xref: /freebsd/lib/libc/stdio/fwrite.c (revision 4f29da19bd44f0e99f021510460a81bf754c21d2)
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  * 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[] = "@(#)fwrite.c	8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "namespace.h"
44 #include <stdio.h>
45 #include "un-namespace.h"
46 #include "local.h"
47 #include "fvwrite.h"
48 #include "libc_private.h"
49 
50 /*
51  * Write `count' objects (each size `size') from memory to the given file.
52  * Return the number of whole objects written.
53  */
54 size_t
55 fwrite(buf, size, count, fp)
56 	const void * __restrict buf;
57 	size_t size, count;
58 	FILE * __restrict fp;
59 {
60 	size_t n;
61 	struct __suio uio;
62 	struct __siov iov;
63 
64 	iov.iov_base = (void *)buf;
65 	uio.uio_resid = iov.iov_len = n = count * size;
66 	uio.uio_iov = &iov;
67 	uio.uio_iovcnt = 1;
68 
69 	FLOCKFILE(fp);
70 	ORIENT(fp, -1);
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 	    count = (n - uio.uio_resid) / size;
78 	FUNLOCKFILE(fp);
79 	return (count);
80 }
81