Path: utzoo!utgpu!water!watmath!clyde!rutgers!labrea!decwrl!pyramid!voder!apple!tecot
From: tecot@apple.UUCP (Ed Tecot)
Newsgroups: comp.sys.mac
Subject: Re: Control Panel Bug?
Message-ID: <7114@apple.UUCP>
Date: 25 Dec 87 06:13:51 GMT
References: <9931@ut-sally.UUCP> <3646@husc6.harvard.edu> <9948@ut-sally.UUCP>
Reply-To: tecot@apple.UUCP (Ed Tecot)
Organization: Apple Computer Inc., Cupertino, USA
Lines: 35

In article <9948@ut-sally.UUCP> brian@ut-sally.UUCP (Brian H. Powell) writes:
>> 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.
>
>In article <3646@husc6.harvard.edu>, singer@endor.harvard.edu (Rich Siegel) writes:
>< 	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.
>
>     That's sounds like a good idea, but I've got a question about it.  I
>presume I should then have global handles to the cursors.  I shouldn't have
>them locked.  So, my call would be
>	SetCursor(*watch_cursor_hdl);   /* in C */
>
>     But what if the cursor relocates while the watch is being displayed?  I
>guess the question is, "Does SetCursor make a copy of the cursor and use that,
>or does it use the actual cursor that it's given?"  If it's the latter, I'll
>have to copy the cursor into a non-relocatable block of memory and use it
>there.  What a waste.

Yes, SetCursor does copy the cursor.  I'd also recommend not using global
variables, instead, simply use the following:
	theCursor = GetCursor(cursorID);
	if (theCursor != nil) SetCursor(*theCursor);

or in Pascal:
	theCursor := GetCursor(cursorID);
	IF theCursor <> NIL THEN SetCursor(theCursor^^);

						_emt