Date: Mon, 5 Oct 1998 13:47:19 +0200 (MET DST)
From: Olivier Perron <perron AT art DOT alcatel DOT fr>
X-Sender: perron AT rtbsci146s
To: Tal Lavi <ranla AT post DOT tau DOT ac DOT il>
Cc: djgpp AT delorie DOT com
Subject: Re: cwsdpmi problem
In-Reply-To: <36131AC7.53E8@post.tau.ac.il>
Message-Id: <Pine.GSO.4.05.9810051331100.14867-100000@rtbsci146s>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Reply-To: djgpp AT delorie DOT com

On Wed, 30 Sep 1998, Tal Lavi wrote:

> Olivier Perron wrote:
> > 
> > On Tue, 29 Sep 1998, Tal Lavi wrote:
> > 
> > > Hi all,
> > >
> > > My compiled DJGPP c program seem to run fine while in dos window in
> > > win95. But when i'm in dos, and i'm running cwsdpmi, and then my
> > > program, it boots my machine!
> > >
> > > does anyone knows why?
> > >
> > >               virge  ranla AT post DOT tau DOT ac DOT il
> > >
> > you certainly dereference a null pointer.
> > Look at your code where you could use a null pointer.
> > 
> > Olivier.
> 
> are you sure?
> why does it work fine with the win95 dpmi server?
> 
The Win95 dpmi server is only DPMI 0.9 compliant and cwsdpmi implements
some of the DPMI 1.0 functions such as capturing and disallowing illegal
dereference of pointers which point to addresses less than 1000h (null
pointers).

See FAQ chapter 9.1 (faq211b.zip in the v2 directory in the same place you
got DJGGP)  for more detailed explanations.

And I just wanted to say that dereferencing a null pointer *might* be the
cause of your problem, not that it *is* the cause. It was just a hint to
help you find your problem.

Olivier.