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. 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.\" from: @(#)strcat.3 8.1 (Berkeley) 6/4/93 37.\" $NetBSD: strcat.3,v 1.13 2003/04/16 13:34:49 wiz Exp $ 38.\" 39.Dd August 11, 2002 40.Dt STRCAT 3 41.Os 42.Sh NAME 43.Nm strcat , 44.Nm strncat 45.Nd concatenate strings 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In string.h 50.Ft char * 51.Fn strcat "char * restrict s" "const char * restrict append" 52.Ft char * 53.Fn strncat "char * restrict s" "const char * restrict append" "size_t count" 54.Sh DESCRIPTION 55The 56.Fn strcat 57and 58.Fn strncat 59functions 60append a copy of the null-terminated string 61.Fa append 62to the end of the null-terminated string 63.Fa s , 64then add a terminating 65.Ql \e0 . 66The string 67.Fa s 68must have sufficient space to hold the result. 69.Pp 70The 71.Fn strncat 72function 73appends not more than 74.Fa count 75characters where space for the terminating 76.Ql \e0 77should not be included in 78.Fa count . 79.Sh RETURN VALUES 80The 81.Fn strcat 82and 83.Fn strncat 84functions 85return the pointer 86.Fa s . 87.Sh EXAMPLES 88The following appends 89.Dq Li abc 90to 91.Dq Li chararray : 92.Bd -literal -offset indent 93char *letters = "abcdefghi"; 94 95(void)strncat(chararray, letters, 3); 96.Ed 97.Pp 98The following example shows how to use 99.Fn strncat 100safely in conjunction with 101.Xr strncpy 3 . 102.Bd -literal -offset indent 103char buf[BUFSIZ]; 104char *input, *suffix; 105 106(void)strncpy(buf, input, sizeof(buf) - 1); 107buf[sizeof(buf) - 1] = '\e0'; 108(void)strncat(buf, suffix, sizeof(buf) - 1 - strlen(buf)); 109.Ed 110.Pp 111The above will copy as many characters from 112.Dq Li input 113to 114.Dq Li buf 115as will fit. 116It then appends as many characters from suffix as will fit (or none 117if there is no space). 118For operations like this, the 119.Xr strlcpy 3 120and 121.Xr strlcat 3 122functions are a better choice, as shown below. 123.Bd -literal -offset indent 124(void)strlcpy(buf, input, sizeof(buf)); 125(void)strlcat(buf, suffix, sizeof(buf)); 126.Ed 127.Sh SEE ALSO 128.Xr bcopy 3 , 129.Xr memccpy 3 , 130.Xr memcpy 3 , 131.Xr memmove 3 , 132.Xr strcpy 3 , 133.Xr strlcat 3 , 134.Xr strlcpy 3 135.Sh STANDARDS 136The 137.Fn strcat 138and 139.Fn strncat 140functions 141conform to 142.St -isoC99 . 143