143 lines
3.9 KiB
Groff
143 lines
3.9 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)strcat.3 8.1 (Berkeley) 6/4/93
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.\" $NetBSD: strcat.3,v 1.12 2003/01/07 17:12:54 wiz Exp $
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.\"
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.Dd August 11, 2002
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.Dt STRCAT 3
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.Os
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.Sh NAME
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.Nm strcat ,
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.Nm strncat
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.Nd concatenate strings
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include \*[Lt]string.h\*[Gt]
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.Ft char *
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.Fn strcat "char * restrict s" "const char * restrict append"
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.Ft char *
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.Fn strncat "char * restrict s" "const char * restrict append" "size_t count"
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.Sh DESCRIPTION
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The
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.Fn strcat
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and
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.Fn strncat
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functions
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append a copy of the null-terminated string
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.Fa append
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to the end of the null-terminated string
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.Fa s ,
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then add a terminating
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.Ql \e0 .
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The string
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.Fa s
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must have sufficient space to hold the result.
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.Pp
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The
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.Fn strncat
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function
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appends not more than
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.Fa count
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characters where space for the terminating
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.Ql \e0
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should not be included in
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.Fa count .
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.Sh RETURN VALUES
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The
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.Fn strcat
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and
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.Fn strncat
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functions
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return the pointer
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.Fa s .
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.Sh EXAMPLES
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The following appends
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.Dq Li abc
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to
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.Dq Li chararray :
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.Bd -literal -offset indent
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char *letters = "abcdefghi";
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(void)strncat(chararray, letters, 3);
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.Ed
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.Pp
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The following example shows how to use
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.Fn strncat
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safely in conjunction with
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.Xr strncpy 3 .
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.Bd -literal -offset indent
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char buf[BUFSIZ];
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char *input, *suffix;
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(void)strncpy(buf, input, sizeof(buf) - 1);
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buf[sizeof(buf) - 1] = '\e0';
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(void)strncat(buf, suffix, sizeof(buf) - 1 - strlen(buf));
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.Ed
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.Pp
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The above will copy as many characters from
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.Dq Li input
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to
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.Dq Li buf
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as will fit.
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It then appends as many characters from suffix as will fit (or none
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if there is no space).
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For operations like this, the
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.Xr strlcpy 3
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and
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.Xr strlcat 3
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functions are a better choice, as shown below.
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.Bd -literal -offset indent
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(void)strlcpy(buf, input, sizeof(buf));
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(void)strlcat(buf, suffix, sizeof(buf));
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.Ed
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.Sh SEE ALSO
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.Xr bcopy 3 ,
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.Xr memccpy 3 ,
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.Xr memcpy 3 ,
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.Xr memmove 3 ,
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.Xr strcpy 3 ,
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.Xr strlcat 3 ,
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.Xr strlcpy 3
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.Sh STANDARDS
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The
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.Fn strcat
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and
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.Fn strncat
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functions
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conform to
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.St -isoC99 .
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