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From: dmb@TIS.COM (David M. Baggett)
Newsgroups: comp.sys.atari.st
Subject: Changing Rez:  What we _really_ want to know
Message-ID: <8912301917.AA19200@TIS.COM>
Date: 30 Dec 89 19:17:48 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 62

A bit of summary for those just tuning in:

I asked if you could change rez without the Bios.  Atari's Derek Mui
said "No."

Then Neil Forsyth asked if you could restore the desktop resolution
from within a function installed at GEM process termination vector 0x102.

Allan said:

    Yes.  I wrote an off-the-cuff article "all about terminate handlers" 
    on GEnie, then asked John Townsend to post it here.  I don't know if he
    has, but among other things, it says you can make BIOS and XBIOS calls
    but not GEMDOS calls.

Then Ken said:

    Neil asks if there are magic negative-offset line A variables which can be
    stuffed with appropriate values to fool GEM if an application changes res.

    The answer is: No.

    [AES has no published variables so you can't tell it about res changes]

    Derek Mui is very wise in the ways of the AES, and when he says there
    is no way, legal or illegal... believe him!

And now (me):

We believe!  We believe!

OK, OK, we know you can't tell AES and GEM about the rez change.  But
suppose we _don't care_ about GEM and AES and we just want the VDI/line A
to work correctly.  My problem isn't with GEM or AES, but rather with the
VT52 emulator.  Here's the scenario:

	1) Run program from (medium rez) GULAM.
	2) In program, change rez to low.  AES is screwed.  I don't care.
	3) Process termination occurs.  I switch back to medium rez
	   _without the Bios_.
	4) GULAM thinks the screen is only 40 columns wide.  Bummer.

Although Allan says you can call the Bios from within a routine installed
as process termination handler (at 0x102), I sure couldn't.  Adding the
single line

	Setscreen(-1L, -1L, 1);

causes my program to crash horribly.

The point is, I just want to be able to duplicate the functionality of
Setscreen without calling the Bios.  Either that, or I'd like to find
out what the secret is to calling Bios routines at process termination.

Ideas?

Thanks,
Dave Baggett
(dmb@TIS.COM)

P.S.> Could some kind soul please repost the "all about terminate handlers" 
	article here?  Thanks.