Date: Tue, 30 Mar 93 10:13:07 EST
From: DJ Delorie <dj AT ctron DOT com>
To: bob AT plk DOT af DOT mil
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: DOS int 2f (Multiplex service interrupt)


> How does a C program using the djgpp port of GNU C to MSDOS perform the
> software interrupt "int 2f" (the DOS multiplex service interrupt)?  I have
> tried the assembler instruction as well as a call to the gcc function
> int86 (0x2f,&r,&s), both with the same result: both fail, producing an
> exception 47 (2f) error.  In go32 this aborts the program to the DOS
> shell, and in debug32 an exception error message indicates that the interrupt
> was not processed.  My program requires this interrupt to communicate with
> a device handler for a peripheral card, and I have been unable to discover
> how to write a gcc program which causes the desired operation.

As with any interrupt, before you can call it from your application
you need to teach go32 how to handle it (this will change in v2.0).
You must change go32/exphdlr.c to add support for your particular
function.

DJ