Date:	Sun, 11 Jan 1998 14:36:22 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To:	"John M. Aldrich" <fighteer AT cs DOT com>
cc:	djgpp AT delorie DOT com
Subject:	Re: no GUD from emacs in DOS...how debug?
In-Reply-To:	<34B6BC1A.1AB4@cs.com>
Message-ID:	<Pine.SUN.3.91.980111143600.15603N-100000@is>
MIME-Version:	1.0

On Fri, 9 Jan 1998, John M. Aldrich wrote:

> Several folks are working on multithreading projects for DJGPP.  Check
> in the v2tk directory of SimTel to find three such projects: 
> jkthpack.zip, jtlwp12b.zip, and pdmlwp02.zip.

Sorry, multithreading won't help here.  What is needed is a way to run
a subprogram, not a function in the same program, asynchronously with
the parent program.

Actually, strictly asynchronous programs are not required, but we need
at least a way to stop a running subprogram in its tracks, give
control to the parent, then return control to the child program so it
could continue.  At the very least, doing this when the child program
writes to stdout and read from stdin, will be enough to make the Emacs
debugging support work.

In contrast, the DJGPP-related multithreading packages that I saw use
signals to switch between the threads.  This is no good for the case
in point, since signals are deferred during a DOS call, and spawning a
subprogram is of course a DOS call.  So all multithreading stops while
the child program runs.

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