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From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <10204222312.AA16592@clio.rice.edu>
Subject: Re: Malloc/free DJGPP code
To: djgpp-workers AT delorie DOT com
Date: Mon, 22 Apr 2002 18:12:12 -0500 (CDT)
In-Reply-To: <3CC3EFC1.754DB126@yahoo.com> from "CBFalconer" at Apr 22, 2002 07:10:57 AM
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> I considered it, but did not test for it exclusively. 

That's good then.  I know how to test for it in a real application.

> I have never seen unexpected values under W98 AFTER initialization. 

Typically only seen when multitasking.  DOS apps share the same
address space, so if DPMI #1 allocates some blocks, DPMI #2 starts
running, DPMI #1 exits, then DPMI #2 can get blocks below it's 
initial address space. If the address space is fragmented you can
also see the same issues.

> If anything were actually happening it would be trivial to add
> just such a test to the fakesbrk generator in tnmalloc.  As it is,
> I shall avoid disturbing anything unless I decide a real bug
> exists.  It is hard to test/evaluate a moving target.

Not so easy - need to show some negative addresses and some "fill"
blocks which are > 0x80000000 in size.  In this case it's easier 
just to test with the real thing.

> Notice that there is a serious realloc problem with the existing
> code, as shown by the evilalgo program.

In V2.03 yes.  Does this problem still exist in the CVS/2.04 current
release?  It had changes made to it's realloc() algorithm, so it
might not have this problem.  I don't know if anyone has tested either
way.  What's in 2.03 isn't usually the most recent version.