1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 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. 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 18.\" without specific prior written permission. 19.\" 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 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)strcat.3 8.1 (Berkeley) 6/4/93 33.\" $NetBSD: strcat.3,v 1.16 2006/10/16 08:48:45 wiz Exp $ 34.\" 35.Dd August 11, 2002 36.Dt STRCAT 3 37.Os 38.Sh NAME 39.Nm strcat , 40.Nm strncat 41.Nd concatenate strings 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In string.h 46.Ft char * 47.Fn strcat "char * restrict s" "const char * restrict append" 48.Ft char * 49.Fn strncat "char * restrict s" "const char * restrict append" "size_t count" 50.Sh DESCRIPTION 51The 52.Fn strcat 53and 54.Fn strncat 55functions 56append a copy of the nul-terminated string 57.Fa append 58to the end of the nul-terminated string 59.Fa s , 60then add a terminating 61.Ql \e0 . 62The string 63.Fa s 64must have sufficient space to hold the result. 65.Pp 66The 67.Fn strncat 68function 69appends not more than 70.Fa count 71characters where space for the terminating 72.Ql \e0 73should not be included in 74.Fa count . 75.Sh RETURN VALUES 76The 77.Fn strcat 78and 79.Fn strncat 80functions 81return the pointer 82.Fa s . 83.Sh EXAMPLES 84The following appends 85.Dq Li abc 86to 87.Dq Li chararray : 88.Bd -literal -offset indent 89char *letters = "abcdefghi"; 90 91(void)strncat(chararray, letters, 3); 92.Ed 93.Pp 94The following example shows how to use 95.Fn strncat 96safely in conjunction with 97.Xr strncpy 3 . 98.Bd -literal -offset indent 99char buf[BUFSIZ]; 100char *input, *suffix; 101 102(void)strncpy(buf, input, sizeof(buf) - 1); 103buf[sizeof(buf) - 1] = '\e0'; 104(void)strncat(buf, suffix, sizeof(buf) - 1 - strlen(buf)); 105.Ed 106.Pp 107The above will copy as many characters from 108.Dq Li input 109to 110.Dq Li buf 111as will fit. 112It then appends as many characters from suffix as will fit (or none 113if there is no space). 114For operations like this, the 115.Xr strlcpy 3 116and 117.Xr strlcat 3 118functions are a better choice, as shown below. 119.Bd -literal -offset indent 120(void)strlcpy(buf, input, sizeof(buf)); 121(void)strlcat(buf, suffix, sizeof(buf)); 122.Ed 123.Sh SEE ALSO 124.Xr bcopy 3 , 125.Xr memccpy 3 , 126.Xr memcpy 3 , 127.Xr memmove 3 , 128.Xr strcpy 3 , 129.Xr strlcat 3 , 130.Xr strlcpy 3 131.Sh STANDARDS 132The 133.Fn strcat 134and 135.Fn strncat 136functions 137conform to 138.St -isoC-99 . 139