From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <10001021628.AA02691@clio.rice.edu>
Subject: Re: GDB, DOS 6.22, CWSDPMI and Interrupts
To: eliz AT is DOT elta DOT co DOT il (Eli Zaretskii)
Date: Sun, 2 Jan 100 10:28:42 -0600 (CST)
Cc: salvador AT inti DOT gov DOT ar, djgpp-workers AT delorie DOT com
In-Reply-To: <Pine.SUN.3.91.1000102110330.1710R-100000@is> from "Eli Zaretskii" at Jan 2, 0 11:03:57 am
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> It could be a CWSDPMI bug, since it doesn't happen with QDPMI.  The
> simple test program posted by Salvador (reproduced below) prints 1
> when run under QDPMI inside a debugger, but 0 when CWSDPMI is the
> host.

Well, from my point of view, that really sucks.

> What I cannot figure out is the difference(s) between what CWSDPMI
> does when a program runs under a debugger and outside a debugger.
> dbgcom.c hooks Int 31h, so there's a user handler involved as far as
> CWSDPMI is concerned, but how should that matter?  Charles, any
> guidance where to look?

Back in r3? r2? there were optimizations added to handle int31 mostly in
protected mode, and it's quite possible when hooked they don't handle the
interrupt flag right.  We probably ought to try it on the previous 
releases of CWSDPMI (beta 9 - r3) and see when it worked, if ever.