Date: Thu, 18 Sep 1997 12:06:51 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Mitchell Spector <spector AT EnchantedLearning DOT com>
cc: djgpp AT delorie DOT com
Subject: Re: DJGPP, interprocess communication, and DPMI
In-Reply-To: <341FEC5F.77F2@EnchantedLearning.com>
Message-ID: <Pine.SUN.3.91.970918120449.1776B-100000@is>
MIME-Version: 1.0
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On Wed, 17 Sep 1997, Mitchell Spector wrote:

> Can a DJGPP program running in a DOS box under Windows 95
> communicate with another currently-running program (either
> another DJGPP program in a different DOS box or a regular
> Win32 app)?

One way that's simple to implement is to use the Windows clipboard.
A bunch of functions of Interrupt 2Fh let DOS programs get and put
text from and to the Windows clipboard.  Look in Ralf Brown's
Interrupt List, under W-2F1700 (WINOLDAP) and thereabouts.

For example, the DJGPP port of Emacs uses this interface to support
the clipboard cut/paste operation, and as a consequence, you can move
text between two instances of Emacs that run on the same machine.

This method uses DOS memory, so it's inherently limited to the amount
of free DOS memory your program has (usually, at least 500K should be
available, but your mileage may vary).

The only other way is to write a VxD, I think.  But I'm no expert in
the ways of tweaking Windows to do what you need, so don't take this 
as the definitive opinion.