Date: Tue, 29 Nov 94 10:17:40 -0500
From: dj AT stealth DOT ctron DOT com (DJ Delorie)
To: nigel AT algor DOT co DOT uk
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu, trav AT clark DOT edu
Subject: Re: Interrupts

>  > One other problem is that you can't do anything in a real mode
>  > callback (or interrupt) that might cause a mode switch.  Basically,
>  > you can do integer math and maybe call a function or two - it's pretty
>  > limited.  It may work sometimes, but it's not guaranteed.
> 
> What happens if the real-mode callback/interrupt handler page faults?  

Unknown.  In non-dpmi mode, go32 handles it correctly, excepting DOS
reentrancy issues.  In DPMI mode, you're supposed to lock it.  1.12
allows the locking call in all modes, but only honors it in DPMI mode,
and V2 honors it always.