Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Memory, what *REALLY* will relocate/purge heap?
Keywords: Memory, heap zone
Message-ID: <9439@hoptoad.uucp>
Date: 30 Dec 89 22:51:21 GMT
References: <5847@sdcc6.ucsd.edu>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 23

In article <5847@sdcc6.ucsd.edu> ma199at@sdcc6.ucsd.edu (L J Cris) writes:
>Can someone explain to me why DisposHandle, DisposPtr or
>SndDisposeChannel and many other dispose routines would scramble/purge
>the heap? 
>
>All they do is deallocate memory, don't they? Other than the memory
>you want to release, what else would be affected?

That's probably correct, but what the list is really about is "routines
you can't call at interrupt time".  Because the heap data structures
might be in mid-revision when an interrupt is invoked, it would be unsafe
to call these rouines during an interrupt.

Perhaps a better course would have been for Apple to distinguish between
routines that may cause relocation and routines which can't be called at
interrupt time, but since they merged the two lists (and the former is a
subset of the latter) you can't count on handles remaining still even
when routines like DisposPtr are called.
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

"Next prefers its X and T capitalized.  We'd prefer our name in lights in
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