Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!decwrl!claris!outpost.UUCP!peirce
From: peirce@outpost.UUCP (Michael Peirce)
Newsgroups: comp.sys.mac.system
Subject: Re: True Multitasking
Message-ID: <0B010004.qmnkzq@outpost.UUCP>
Date: 19 Jan 91 23:38:53 GMT
Reply-To: peirce@outpost.UUCP
Organization: Peirce Software
Lines: 32
X-Mailer: uAccess - Mac Release: 1.0.3


In article <1991Jan18.195343.6636@everexn.com>, drew@everexn.com (Drew Rogge) writes:
> 
> In article <11745@goofy.Apple.COM> lsr@Apple.com (Larry Rosenstein) writes:
> >MPW tools (including the compiler) run nicely in the background.  In fact,
> >it is very easy to take some generic C utility and make it run in the 
> >background under MPW.
> 
> Does anyone know if there is a function that an MPW tool can call which will
> yield control of the CPU for a while to give other tasks a chance to run?
> I ported Dave Buck's raytracer, DKBTrace, to run as an MPW tool but the
> response time of the system was horrible when it was running. The program
> is very compute bound and doesn't call out to the system very often.

Look in the files CursorCtl.p in the PInterfaces (or the C equivalent).
The following routines are declared there:

	InitCursorCtl(newCursors) - Init CursorCtl to load the 'acur' resource
	RotateCursor(counter) - Sequence through cursor frames for counter mod 32
	SpinCursor(increment) - Sequence mod 32 incrementing internal counter
	Hide_Cursor() - Hide the current cursor
	Show_Cursor(cursorKind) - Show the cursor

Every time you call these routines, MPW yields CPU time too.  It even
handles command-. for canceling the tool execution.

-- michael


--  Michael Peirce         --   outpost!peirce@claris.com
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