From: Nate Eldredge <neldredge AT hmc DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: WARNING: DOS is about to die
Date: Tue, 07 Sep 1999 23:25:00 -0700
Organization: Harvey Mudd College
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Rez wrote:
> 
> Shawn Hargreaves wrote:
> > things back a bit further in the right direction, I find the Linux
> > DOSEMU program does a much better job of running djgpp programs than
> > an NT dos box (it even supports SVGA VESA graphics in a window!),
> 
> Question, then: I beta-test for a coder who works with DJGPP under
> Win95. I test our app exclusively in real       DOS. About half the time when
> there's a bug, the program runs just fine under Win95 in a DOS box (both
> for the coder and my testing partner) but segviols before it even gets
> fully loaded under real DOS with CWSDPMI. Sometimes this happens even
> with trivial bugs, like a wonked menu item. I realise this is vague, but
> anything in particular which causes this dichotomy (bug has no effect
> under Win95, dies spectacularly under DOS) ???  ISTM if we knew what
> sort of things cause this, we (ie. our coder) could avoid 'em up front.
> 
> I'm tempted to rename this thread "DOS kills escaped bugs" :)

NULL pointers dereferences, usually.  Windows doesn't provide the DPMI
service necessary to trap them, but CWSDPMI does.

However, I suspect your coder is already doing everything possible to
avoid that. :)
-- 

Nate Eldredge
neldredge AT hmc DOT edu