Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!sun-barr!ccut!titcca!kddlab!atrpost!atr-la!alain
From: alain@atr-la.atr.co.jp (Alain de Cheveigne)
Newsgroups: comp.sys.mac.programmer
Subject: anything wrong with MacsBug 5.5 on a IIx ?
Message-ID: <3905@atr-la.atr.co.jp>
Date: 3 Jan 90 10:45:47 GMT
Organization: ATR International,Japan
Lines: 33


With Heap Scramble set from MacsBug, my application systematically
falls into MacsBug with a line labeled "InitGraf" (or even just the
register display).  MPW 3.0 crashes the same.  It happens erratically,
often just while the mouse is moving.

I managed to narrow things down so that my program crashes within this loop:

	Point		p;
	extended	top;
	[port is set to a window]

	while (StillDown()) {
		GetMouse(&p);				
		top = (extended) p.v;
	}

It got progressively more difficult to make it crash as I removed
things from the loop, and I didn't manage to make it crash without the
assignment line.

I can't imagine what is going wrong here: I don't touch the heap, the
calls seem harmless.  All I can imagine is that some other part of my
program damaged MacsBug or a patch to StillDown() or GetMouse(), but
then I'm surprised it doesn't crash sooner.

I'm on a Mac IIx, 8mb, system 6.03, using MPW 3.0 and MacsBug 5.5 (July
14th 1987).  Multifinder (crashes even without), no inits.

Any ideas ?

Alain de Cheveigne,
alain@atr-la.atr.co.jp