From: "John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: malloc and SIGSEGV
Date: Tue, 12 Nov 1996 18:34:45 -0800
Organization: Three pounds of chaos and a pinch of salt
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Message-ID: <328933C5.1ABA@cs.com>
References: <32883519 DOT 41C67EA6 AT informatik DOT uni-hildesheim DOT de>
Reply-To: fighteer AT cs DOT com
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To: Ingo Stierand <stierand AT informatik DOT uni-hildesheim DOT de>
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Ingo Stierand wrote:
> 
> Hy,
> I have a little problem with malloc. In the X'th malloc my program
> will abort with SIGSEGV. Is this a known problem?

Yes.  In general, it's a bad idea to do extremely large numbers of
mallocs, but the instance you report is a slight limitation in the
cwsdpmi DPMI host for djgpp.  Solution:

1) Make sure you have the latest version of cwsdpmi: 
v2misc/csdpmi3b.zip

2) Read the file 'CWSPARAM.DOC' that comes with the distribution, and
then run 'cwsparam' to increase the internal heap size of cwsdpmi.exe. 
Increasing the heap size directly increases the number of simultaneous
memory blocks you can allocate, but increases the memory footprint of
cwsdpmi.

3) Even though the above will solve your problem, I recommend highly
that you work to make your program more efficient in its use of memory
by allocating large blocks and dividing them up as necessary.  This is a
good programming technique as well.

FYI, cwsdpmi is the only host that suffers from this problem - Windoze,
QDPMI, 386MAX, et. al., seem to be perfectly fine for large numbers of
allocations.  But that's the tradeoff you make for greater performance
and efficiency.  :)

-- 
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| John M. Aldrich, aka Fighteer I  |        fighteer AT cs DOT com         |
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