Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!cs.utexas.edu!ut-emx!jdm
From: jdm@ut-emx.UUCP (Jim Meiss)
Newsgroups: comp.sys.mac.programmer
Subject: DA problem under Multifinder
Keywords: LSC, option key, DA Handler
Message-ID: <8268@ut-emx.UUCP>
Date: 27 Nov 88 23:56:08 GMT
Organization: The University of Texas at Austin, Austin, Texas
Lines: 39


	I'm perplexed about the some weird behavior
in a DA I'm writing using LSC 3.0. 
First the setting: 
	Mac SE
	System 6.02
	multifinder
	DA has dNeedLock and dNeedGoodbye
Here's what I do:
Launch the DA holding down the option key. It will load
itself into the current application's layer...though I note 
that its actually loaded into the system heap 
(like all good da's under multifinder).
	While the DA is thus open, try to open it again,
using the apple menu, but NOT holding down the option key. 
In most cases when you do this to a DA, the DA Handler
is not launched. If you are in a different layer
from the DA, multifinder switches you to the layer
which contains the DA. All well and good however...
	Not so for my DA: Multifinder attempts to launch 
DA handler and open my DA again. It uses the already open
(and locked) DRVR segment in the system heap, but bad 
things happen when DA Handler thinks it should have control
of the DA.
	Now I don't see how this can be my fault, since
all the bad stuff seems to happen before my DRVR open 
routine gets called...
	I checked the system heap, and my DCE is in 
place, locked and properly indicates that the driver is open.

	Any ideas? 
	Does Anyone have an LSC da that doesn't have 
this problem?
	How does multifinder tell that a DRVR is open...
and it shouldn't launch the DA Handler?

			Thanks
			Jim Meiss
			jdm@emx.utexas.edu