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From: tm8t+@andrew.cmu.edu (Tod McQuillin)
Newsgroups: comp.unix.bsd,comp.unix.large,comp.sys.ibm.pc.rt
Subject: Re: strdup
Message-ID: <Qemk4KW00WB98ZYN5Z@andrew.cmu.edu>
Date: 1 Oct 92 05:45:58 GMT
Article-I.D.: andrew.Qemk4KW00WB98ZYN5Z
References: <br.pct.52.717898310@RLG.Stanford.EDU>
<lckirmINNosg@spim.mti.sgi.com>
Organization: Carnegie Mellon, Pittsburgh, PA
Lines: 72
In-Reply-To: <lckirmINNosg@spim.mti.sgi.com>
koblas@mips.com (David Koblas) writes:
> Here's a copy (typed in off the cuff, so I won't say it is
> guaranteed to work):
>
> char *strdup(char *str)
> {
> char *cp = (char *)malloc(strlen(str));
> return cp ? strcpy(cp, str), cp : NULL;
> }
>
Good thing you included a dislaimer. You need to use
malloc(strlen(str)+1) else the null terminator may trash the heap.
Here is the 4.3BSD-reno version: (sorry about the long copyright but they
insist you leave it in)
/*
* Copyright (c) 1988 The Regents of the University of California.
* All rights reserved.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strdup.c 5.4 (Berkeley) 2/24/91";
#endif /* LIBC_SCCS and not lint */
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
char *
strdup(str)
const char *str;
{
int len;
char *copy;
len = strlen(str) + 1;
if (!(copy = malloc((u_int)len)))
return((char *)NULL);
bcopy(str, copy, len);
return(copy);
}