Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!gatech!hubcap!mikeoro
From: mikeoro@hubcap.clemson.edu (Michael K O'Rourke)
Newsgroups: comp.sys.mac.programmer
Subject: VBL interrupts
Message-ID: <6082@hubcap.clemson.edu>
Date: 28 Jul 89 01:04:47 GMT
Organization: Clemson University, Clemson, SC
Lines: 14

This may turn out to be a really stupid question but here it goes:

I had the distinct impression that VBL's could NOT call any routines
that move memory or the machine would crash.  However, in the February
1989 MacTutor, there is an example VBL that call the routine PlotIcon
from within the VBL.  The IM DA says that PlotIcon may move memory.

So who is right? Is the IM DA wrong about that call?  Did the person
(Dick Chandler of Apple) who wrote the VBL do something illegal?  Are routines
that move memory okay sometimes, but not others?

Confusedly,

Michael O'Rourke