Date: Wed, 25 Nov 1992 22:45:30 EST
From: sandmann AT clio DOT rice DOT edu (Charles Sandmann 713-493-8756)
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: gdb for DOS (and gcc for OS/2)

The EMX port of GCC (available on ftp-os2.nmsu.edu) supports gdb under DOS.
For a minimal test, you need emxdev.zip, gnudev.zip, and unzip.exe (V5, not PK).
The emx/doc/install.doc file gives instructions on how to bring up gdb.  (It's
as simple as adding -g to the compile and saying gdb filename.exe).

I find this port useful since it supports termcap/curses stuff, <termio.h>
and some other features not available in DJGPP.  From my current experience,
it does not allow you to get as close to the hardware as DJGPP, so touching
the real mode 1 meg I don't know how to do.  It also does not support the
nice event library and graphics packages that DJGPP does.

So, depending on what you are porting (and how much) you might want both.
I keep both, since some things port easier on one, some on the other.  If
you have a spare 4 megs for the base stuff (no C++ or extras) give it a try.
The C++, curses, and other stuff like TexInfo reader take another 2Mb or so.
The same package runs under OS/2 2.0 and makes dual mode .exe images for
those interested.

From what I infer from the rather thick documentation, the extender
supports 4 virtual processes (?) which is how it is able to make gdb work.
For those with zero interest in OS/2, you also have to wade through lots
of documentation/code which works only under OS/2.