From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Bug in Allegro? Something strange is happening...
Date:	Tue, 4 Mar 1997 19:58:46 +0000
Organization:	None
Distribution:	world
Message-ID:	<h5HbZaA27HHzEwbZ@talula.demon.co.uk>
References:	<5fg406$mh5 AT news DOT indy DOT net>
NNTP-Posting-Host:	talula.demon.co.uk
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Chris Frolik writes:
>I wrote a simple program that uses the keyboard and joystick to allow the 
>player to move a sprite around on the screen.  I found that it runs fine in 
>Windows 95, but it halts right away when I run it in DOS.  When I run it in 
>DOS, I get the following:

In my experience, this is usually the result of dereferencing a NULL
pointer: Windows lets you do that, while CWSDPMI gets upset (very
sensibly, since it's a nasty programming error). 

As to what's causing the problem, it would help if you posted some
sources. Try to isolate the minimum piece of code that demonstrates the
problem (half the time you'll locate the mistake while doing that), and
the chances are someone will be able to tell you what's wrong with it...

>Call frame traceback EIPs:
>  0x00022d72
>  0x00001b46
>  0x0002298a

When you get one of these, try running symify on the program that
crashed (compile it with the -g option, then type 'symify myprog.exe').
That will tell you exactly what line of which function caused the crash.

/*
 *  Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
 *  Beauty is a French phonetic corruption of a short cloth neck ornament.
 */

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