usr/src/lib/libc/port/gen/strncat.c

   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.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include <string.h>
  34 #include <sys/types.h>
  35
  36 /*
  37  * Concatenate s2 on the end of s1.  S1's space must be large enough.
  38  * At most n characters are moved.
  39  * Return s1.
  40  */
  41 char *
  42 strncat(char *s1, const char *s2, size_t n)
  43 {
  44         char *os1 = s1;
  45
  46         n++;
  47         while (*s1++)
  48                 ;
  49         --s1;
  50         while (*s1++ = *s2++)
  51                 if (--n == 0) {
  52                         s1[-1] = '\0';
  53                         break;
  54                 }
  55         return (os1);
  56 }