xref: /titanic_44/usr/src/lib/libc/port/gen/strnlen.c (revision 49b225e1cfa7bbf7738d4df0a03f18e3283426eb)
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 2008 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 #include "lint.h"
30 #include <string.h>
31 #include <sys/types.h>
32 
33 /*
34  * Returns the number of non-NULL bytes in string argument,
35  * but not more than maxlen.  Does not look past str + maxlen.
36  */
37 size_t
38 strnlen(const char *str, size_t maxlen)
39 {
40 	const char *ptr;
41 
42 	ptr = memchr(str, 0, maxlen);
43 	if (ptr == NULL)
44 		return (maxlen);
45 
46 	return (ptr - str);
47 }
48