xref: /illumos-gate/usr/src/lib/libc/port/gen/strnlen.c (revision 160abee025ef30c34521b981edd40ffcaab560aa)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2006 Sun Microsystems, Inc.
24  * All rights reserved.  Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #pragma	weak	strnlen = _strnlen
30 
31 #include "synonyms.h"
32 #include <string.h>
33 #include <sys/types.h>
34 
35 /*
36  * Returns the number of non-NULL bytes in string argument,
37  * but not more than maxlen.  Does not look past str + maxlen.
38  */
39 size_t
40 strnlen(const char *str, size_t maxlen)
41 {
42 	const char *ptr;
43 
44 	ptr = memchr(str, 0, maxlen);
45 	if (ptr == NULL)
46 		return (maxlen);
47 
48 	return (ptr - str);
49 }
50