xref: /dragonfly/lib/libc/string/strncat.c (revision 19fe1c42)
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  * @(#)strncat.c	8.1 (Berkeley) 6/4/93
37  * $FreeBSD: src/lib/libc/string/strncat.c,v 1.1.1.1.14.1 2001/07/09 23:30:07 obrien Exp $
38  * $DragonFly: src/lib/libc/string/strncat.c,v 1.4 2005/09/18 16:32:34 asmodai Exp $
39  */
40 
41 #include <sys/cdefs.h>
42 #include <string.h>
43 
44 /*
45  * Concatenate src on the end of dst.  At most strlen(dst)+n+1 bytes
46  * are written at dst (at most n+1 bytes being appended).  Return dst.
47  */
48 char *
49 strncat(char *dst, const char *src, size_t n)
50 {
51 	if (n != 0) {
52 		char *d = dst;
53 		const char *s = src;
54 
55 		while (*d != 0)
56 			d++;
57 		do {
58 			if ((*d = *s++) == 0)
59 				break;
60 			d++;
61 		} while (--n != 0);
62 		*d = 0;
63 	}
64 	return (dst);
65 }
66