From 062d999e00c36692605b1ac394ffcfbb340e1771 Mon Sep 17 00:00:00 2001 From: millert <> Date: Thu, 19 Dec 2013 20:52:37 +0000 Subject: Split out strncpy and strncat from strcpy and strcat manuals. Requested by deraadt@ --- src/lib/libc/string/strncat.3 | 128 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 src/lib/libc/string/strncat.3 (limited to 'src/lib/libc/string/strncat.3') diff --git a/src/lib/libc/string/strncat.3 b/src/lib/libc/string/strncat.3 new file mode 100644 index 0000000000..38eabe3474 --- /dev/null +++ b/src/lib/libc/string/strncat.3 @@ -0,0 +1,128 @@ +.\" $OpenBSD: strncat.3,v 1.1 2013/12/19 20:52:37 millert Exp $ +.\" +.\" Copyright (c) 1990, 1991 The Regents of the University of California. +.\" All rights reserved. +.\" +.\" This code is derived from software contributed to Berkeley by +.\" Chris Torek and the American National Standards Committee X3, +.\" on Information Processing Systems. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.Dd $Mdocdate: December 19 2013 $ +.Dt STRNCAT 3 +.Os +.Sh NAME +.Nm strncat +.Nd concatenate a string with part of another +.Sh SYNOPSIS +.In string.h +.Ft char * +.Fn strncat "char *s" "const char *append" "size_t count" +.Sh DESCRIPTION +The +.Fn strncat +function appends not more than +.Fa count +characters of the NUL-terminated string +.Fa append +to the end of the NUL-terminated string +.Fa s . +Space for the terminating +.Ql \e0 +should not be included in +.Fa count . +The string +.Fa s +must have sufficient space to hold the result. +.Sh RETURN VALUES +The +.Fn strncat +function returns the pointer +.Fa s . +.Sh EXAMPLES +The following appends +.Dq Li abc +to +.Va chararray : +.Bd -literal -offset indent +char *letters = "abcdefghi"; + +(void)strncat(chararray, letters, 3); +.Ed +.Pp +The following example shows how to use +.Fn strncat +safely in conjunction with +.Xr strncpy 3 . +.Bd -literal -offset indent +char buf[BUFSIZ]; +char *input, *suffix; + +(void)strncpy(buf, input, sizeof(buf) - 1); +buf[sizeof(buf) - 1] = '\e0'; +(void)strncat(buf, suffix, sizeof(buf) - 1 - strlen(buf)); +.Ed +.Pp +The above will copy as many characters from +.Va input +to +.Va buf +as will fit. +It then appends as many characters from +.Va suffix +as will fit (or none +if there is no space). +For operations like this, the +.Xr strlcpy 3 +and +.Xr strlcat 3 +functions are a better choice, as shown below. +.Bd -literal -offset indent +(void)strlcpy(buf, input, sizeof(buf)); +(void)strlcat(buf, suffix, sizeof(buf)); +.Ed +.Sh SEE ALSO +.Xr bcopy 3 , +.Xr memccpy 3 , +.Xr memcpy 3 , +.Xr memmove 3 , +.Xr strcat 3 , +.Xr strcpy 3 , +.Xr strlcpy 3 , +.Xr wcscat 3 , +.Xr wcslcpy 3 +.Sh STANDARDS +The +.Fn strcat +and +.Fn strncat +functions conform to +.St -ansiC . +.Sh HISTORY +The +.Fn strncat +function first first appeared in +.At v7 . -- cgit v1.2.3-55-g6feb