2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
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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
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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
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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("$FreeBSD$");
39 #include "namespace.h"
43 #include "un-namespace.h"
46 #include "libc_private.h"
49 * Write `count' objects (each size `size') from memory to the given file.
50 * Return the number of whole objects written.
53 fwrite(buf, size, count, fp)
54 const void * __restrict buf;
63 * ANSI and SUSv2 require a return value of 0 if size or count are 0.
65 if ((count == 0) || (size == 0))
69 * Check for integer overflow. As an optimization, first check that
70 * at least one of {count, size} is at least 2^16, since if both
71 * values are less than that, their product can't possible overflow
72 * (size_t is always at least 32 bits on FreeBSD).
74 if (((count | size) > 0xFFFF) &&
75 (count > SIZE_MAX / size)) {
83 iov.iov_base = (void *)buf;
84 uio.uio_resid = iov.iov_len = n;
91 * The usual case is success (__sfvwrite returns 0);
92 * skip the divide if this happens, since divides are
93 * generally slow and since this occurs whenever size==0.
95 if (__sfvwrite(fp, &uio) != 0)
96 count = (n - uio.uio_resid) / size;