Path: utzoo!utgpu!news-server.csri.toronto.edu!smoke.cs.toronto.edu!moraes
Newsgroups: comp.lang.c
From: moraes@cs.toronto.edu (Mark Moraes)
Subject: Re: realloc() (was: Re: Safe coding practices)
Message-ID: <91Feb2.170338edt.577@smoke.cs.toronto.edu>
Organization: Department of Computer Science, University of Toronto
References: <23975:Jan2516:36:5891@kramden.acf.nyu.edu> <1991Jan30.121425.16882@unhd.unh.edu> <1991Jan30.193308.3897@athena.mit.edu> <1991Jan30.204210.5593@thyme.jpl.nasa.gov>
Date: 2 Feb 91 22:03:56 GMT
Lines: 13

From the Seventh Edition manual page for malloc(3):
> BUGS
>      When realloc returns 0, the block pointed to by ptr  may  be
>      destroyed.

[This exists in the Eighth and Tenth Edition manuals as well, also
 the 4.3Reno manuals]

So one can't portably rely on the contents of the block being
realloced if the realloc failed.  On the other hand, this behaviour is
clearly marked a bug as far back as V7.

	Mark.