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From: jtn@potomac.ads.com (John T. Nelson)
Newsgroups: comp.sys.mac.programmer
Subject: Questions about multitasking on the mac
Message-ID: <1991May11.191114.27564@potomac.ads.com>
Date: 11 May 91 19:11:14 GMT
Organization: Advanced Decision Systems, Arlington, VA
Lines: 48


No I don't want to start yet ANOTHER flamewar on what type of
multitasking is the One And True Multitasking.  Rather I have a
legitimate question concerning how one passes control onto other apps
running cooperatively on the Mac.  Let's say I have a large and
complex compiler (which I do) and let's say that it consists of lots
of hairy recursive-decent style code.  It's difficult to modularize
this particular code so I can't call lots of modules from the event
loop.  Basically we go into the compiler and come back out when done.

This means that I don't get to call WaitNeXTEvent and thus the
foreground process has total control.  No backgrounding possible
because we don't get to the event loop until complete.

Now, as near as I can tell the only way to provide backgrounding of
this sort would be to do something like the following in EACH AND
EVERY MODULE that I have in the compiler....

a_module(argument1, argument2)
{
blah();
foo();
while( flagSet ) {
	bar();
	baz();
}

DO_WAIT_NEXT_EVENT();
return;

bar()
{
.
.
.
DO_WAIT_NEXT_EVENT();
return;
}


and so on and so on.  In the function DO_WAIT_NEXT_EVENT I have
basically the same calls that I have in the top level event loop.  We
call WaitNeXTEvent and process various events.

I suppose this can be done but its GROSS infusing this event code in
every module to get timely event updates.  I can't figure out a better
way unfortunately.  Anyone have a different philosophy on how this
could be accomplished?