Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: best way to detect command-. interrupt?
Message-ID: <9427@hoptoad.uucp>
Date: 29 Dec 89 21:10:41 GMT
References: <694@nems.dt.navy.mil> <33392@ucbvax.BERKELEY.EDU> <9421@hoptoad.uucp> <3506@husc6.harvard.edu>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 30

In article <3506@husc6.harvard.edu> siegel@endor.UUCP (Rich Siegel) writes:
>	If you wanted to get *really* skanky, you could bottleneck _PostEvent,
>and set a global flag subject to whether the event was for a fan-period.
>This involves saving the application's A5 in a safe place, since _PostEvent
>can get called at interrupt time, and you will probably need to test KeyMap
>to look for the Command key...

I pointed out the problem with this in the article you quoted.  If you
are giving time to other applications, then the PostEvent call at
interrupt time may get called in another application's context,
bypassing your application-specific patch.  Due to the way the Event
Manager works, you will still get the keyboard event, but PostEvent may
not be called in your application context. So you can drop Command-Dots
with this method too.  If all applications get equal time, then the
probability of correctly intercepting a Cmd-Dot is the reciprocal of
the number of applications running.

>	Then in whatever operation you'd want to check, just test your global
>flag each time through the loop, or at selective points during the computation.
>It's pretty cheap to do all of this, and can be used in places where you
>don't want to slow down by calling _GetNextEvent or _GetOSEvent...

As long as you're not giving time to other applications, meaning you're
not calling SystemTask, GetNextEvent, or WaitNextEvent, it should
work.  Otherwise not.
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

If you vote for clowns, you have no right to complain that only clowns
make it to the ballot.