Path: utzoo!mnetor!uunet!husc6!endor!singer
From: singer@endor.harvard.edu (Rich Siegel)
Newsgroups: comp.sys.mac
Subject: Re: Control Panel Bug?
Message-ID: <3646@husc6.harvard.edu>
Date: 23 Dec 87 21:55:09 GMT
References: <9931@ut-sally.UUCP>
Sender: news@husc6.harvard.edu
Reply-To: singer@endor.UUCP (Rich Siegel)
Organization: THINK Technologies, Bedford, MA
Lines: 40

In article <9931@ut-sally.UUCP> brian@ut-sally.UUCP (Brian H. Powell) writes:
>
>     In a program I'm working on, I load all the cursors that I am going to
>use at the beginning of the program, move them to high memory, lock them down,
>dereference the handles and use pointers to them for the duration of the
>program.  Fine.

	No, this is not fine. I will explain.

>     After playing around with the control panel, I noticed that my watch
>cursor had turned into mush.  I tried a few other DAs, but I couldn't get them
>to exhibit this behavior.  I did a step spy on the handle and found out that
>somebody is unlocking the handle.  I'm not sure if it's the control panel or
>the OpenDeskAcc code, but it happens in there somewhere.

	It's not good practice to lock a handle, then keep its master pointer
around, because exactly that sort of thing can happen. The best way to
get the same effect is to preload the CURS resources and keep the CursHandles
as global variables.

>     This all reeks of good old Macintosh Technical Note #1, in which is
>discussed the issue of DAs purging system resources, for example, oh, say the
>watch cursor, that might be in use by the application.  This makes me tend to
>believe that the DA is wrong in unlocking my handle.  (As opposed to me being
>wrong expecting locked handles to system resources to stay locked.)

	Tech Note number 1 is clear on the subject of *purging* resources,
but says nothing about locking or unlocking them.

>Brian H. Powell

		--Rich


**The opinions stated herein are my own opinions and do not necessarily
represent the policies or opinions of my employer (THINK Technologies).

* Richard M. Siegel | {decvax, ucbvax, sun}!harvard!endor!singer    *
* Customer Support  | singer@endor.harvard.edu			    *
* Symantec, THINK Technologies Division.  (No snappy quote)         *