From: Charles Sandmann <sandmann AT clio DOT rice DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: PB with multitask
Date: Wed, 19 Jun 2002 12:38:37 CDT
Organization: Rice University, Houston TX
Lines: 10
Message-ID: <3d10c19d.sandmann@clio.rice.edu>
References: <aeqc5s$pl7$1 AT wanadoo DOT fr>
NNTP-Posting-Host: clio.rice.edu
X-Trace: joe.rice.edu 1024508516 18754 128.42.105.3 (19 Jun 2002 17:41:56 GMT)
X-Complaints-To: abuse AT rice DOT edu
NNTP-Posting-Date: 19 Jun 2002 17:41:56 GMT
X-NewsEditor: ED-1.5.9
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

> the program work well, but when I call a bios function the multitasking is
> disable because the task commutation is do by the exceptions. it's possible 
> to forced the exception when I am inside the bios function???

No.  BIOS calls are not reentrant in general, so you can't interrupt them
(or DOS) in a multi-tasking environment.  Even if you could, there is
no way to signal this to the 32-bit DPMI application.

The fix is to avoid calling the BIOS and convert that function to 32-bit
code and put it in your image.