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Date: Mon, 4 Feb 2002 19:08:47 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: Richard <ts_swe_dpt AT yahoo DOT co DOT uk>
cc: djgpp AT delorie DOT com
Subject: Re: go32 wrapped interrupt handler returns register value ?
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On Mon, 4 Feb 2002, Richard wrote:

> Hi, Im trying to return a register value from a software interrupt using the
> go32 wrapper.
> 
> static _go32_dpmi_seginfo int24_wrap;
> static void int24_interrupt(void)
> {
>     // blah blah
>     // How on earth do I set _AL return code here ???
> }

Take a look at the module exceptn.S in the library sources 
(djlsr203.zip): the DJGPP startup code already installs a PM handler for 
Int 24h, and that handler instructs DOS to fail the call.

Note that some DPMI servers (notably, CWDPMI) catch Int 24h themselves 
and fail the call even before your application sees Int 24h.  See section 
22.13 of the DJGPP FAQ list for more fun.