From:	"Charles Sandmann" <sandmann AT clio DOT rice DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: SIGSEGV page fault DOS but not Windows
Date:	Mon, 30 Oct 2000 16:45:22
Organization:	Aspen Technology, Inc.
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Message-ID:	<39fda5a2.sandmann@clio.rice.edu>
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> I have a program which runs fine in a Windows 'DOS window' but produces a
> page fault when run in true W98 DOS.

..

> Any ideas on how I can fix this? I have looked at the FAQ and there are some
> topics that may be relevant but I am not sure which ones really apply to
> this problem - I think the problem is more likely to be with CWSDPMI than
> DJGPP and I suspect it is to do with the configuration of the server or
> perhaps EMM386 but I don't know enough about the ins and outs of DMPI (or
> PC's generally) to work out how to resolve it!

1) Get r5
2) issue the command cwsdpmi -x before running your program
3) run the program

If the problem goes away then this is a null pointer problem (and a bug
in your program).  The -x qualifier (this is a one pass test only) 
disables the 1.0 extensions (and allows Windows developed buggy programs
to run).  You can also permanently disable null pointer checking 
capabilities using cwsparam.  This feature was specifically added for
people who develop under Windows and think ignorance is bliss.

It could be the null pointer is due to a malloc that failed (do you
check all these?)

Have you checked the amount of memory you see using go32-v2?  How does
this compare to the amount you expect to allocate?

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