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From: richard@calvin.spp.cornell.edu (Richard Brittain)
Newsgroups: comp.lang.c
Subject: Re: Malloc in Turbo C
Message-ID: <1990Mar1.161605.19189@calvin.spp.cornell.edu>
Date: 1 Mar 90 16:16:05 GMT
References: <26316@qfagus.OZ> <90058.153755CMH117@psuvm.psu.edu> <52749@bbn.COM>
Reply-To: richard@calvin.spp.cornell.edu (Richard Brittain)
Organization: Cornell Space Plasma Physics Group
Lines: 27

In article <52749@bbn.COM> pdsmith@spca.bbn.com (Peter D. Smith) writes:
>
>C'mon lay off the guy.  Malloc and Free are tough to get right.  A story:
>at a previous job, we built a run time allocation checker (bounds checking,
>freeing the same memory twice, freeing a pointer after incrementing it, not
>freeing memory, allocation statistics... the whole ball of wax). **Every
>single library** by **every single C engineer** had problems!
>
>Most implementations of C are screwed up: they give you a dangerous tool
>but don't give you a handle on double-checking the results.
>
>				Peter D. Smith

As a side note to this side note, I'll just mention that with Turbo-C, the
chances of bombing out if you try to use something from a free'd block are
VERY high, since the free() routine seems to modify the contents of the
block immediately.  I have found cases of code ported from various unix
compilers, and from Microsoft C, which had been doing this succesfully 
and showed up the error right away with TurboC.  In one case the original
author told me the bug had been there over 3 years of development, but
no-one noticed on the other systems.   On a pc, you have even more incentive
to get it right, since getting it wrong often means reaching for the red button.

Richard Brittain,                   School of Elect. Eng.,  Upson Hall   
                                    Cornell University, Ithaca, NY 14853
ARPA: richard@calvin.spp.cornell.edu	
UUCP: {uunet,uw-beaver,rochester,cmcl2}!cornell!calvin!richard