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From: zben@ni.umd.edu (Ben Cranston)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Shared addresses between applications with system 7
Summary: Virtual memory may be a problem
Keywords: Shared data, A5, Memory Manager
Message-ID: <1991Jun19.190324.23720@ni.umd.edu>
Date: 19 Jun 91 19:03:24 GMT
References: <1991Jun12.204031.11225@cec1.wustl.edu> <1991Jun13.145629.14699@eng.umd.edu>
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In article <1991Jun13.145629.14699@eng.umd.edu> russotto@eng.umd.edu
(Matthew T. Russotto) writes:

> ...  Assuming you can pass a pointer from
> one application to another, have one program do a NewPtr, pass the pointer
> (which is an absolute pointer) to the other program.  Then both programs can
> access that area of memory (which actually exists in the first application's
> heap, but that is relatively unimportant...)

If you have virtual memory turned on this may not work, as the first
application (and its heap) may get swapped while the second application
is running.  Maybe the first application can "lock" that area of memory
down somehow (I haven't gotten that far in reading VI yet!!!) but the
better part of valor might be to allocate in the System heap which is
never subject to swapping...