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From: time@ice.com (Tim Endres)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Why won't ResError return the right message?
Message-ID: <1CE00001.falep4@tbomb.ice.com>
Date: 10 May 91 15:55:11 GMT
Reply-To: time@ice.com
Organization: ICE Engineering, Inc.
Lines: 28
X-Mailer: uAccess - Mac Release: 1.1.b5


In article <1991May9.040511.26710@colorado.edu>, pratt@csn.org (Jonathan Pratt) writes:
> >And just to make it worse, *handle won't be NULL for a purged resource,
> >but StripAddress(*handle) will be.  The purge and resource bits are still
> >on (at least in 24 bit memory models).
> >
> Come on.  Programming the Mac is enough work without this kind of dis-
> information.  Next time get a reference.  From Inside Mac:
> 
> 	Before attempting to access any purgeable block, you must
> 	check its handle to make sure the block is still allocated.
> 	If the handle is empty (that is, h^ = NIL, where h is the
> 	handle), then the block has been purged; ...
> 
> Last I heard, NIL still means zero. :-)

Actually, the flags for a handle are stored in the *handle*'s address.
Thus, the dereference (* handle) should contain a "pure" address.
Thus, the StripAddress() should only be required on the handle and
*not* on the handle's dereferenced pointer.

tim.

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