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From: jtn@potomac.ads.com (John T. Nelson)
Newsgroups: comp.sys.mac.programmer
Subject: How to malloc memory VERY dynamically and not out of app heap?
Message-ID: <1991Mar24.172706.20807@potomac.ads.com>
Date: 24 Mar 91 17:27:06 GMT
Organization: Advanced Decision Systems, Arlington, VA
Lines: 40


Here's an interesting problem.  Let's say I want to write a text
editor.  This editor will want to handle files that might be very
small (a couple of bytes) to perhaps several megabytes of text (big
.Hqx files).  To do this, I obviously want to use malloc.  Problem is
that the Mac OS mallocs (or NewPtr if you like) its space out of the
application heap whose size is apparently determined by the
application's suggested size (available from command-I in the Finder).

Okay so far?

Now... in order to handle those BIG files this means that I need an
app size that's extremely large (several megabytes) but that means I
cripple the application because then it won't run on smaller Macs with
perhaps only two meg of memory.  If I set the app size too small then
it doesn't run on those big files.  It would be nice to newPtr my
space from a "free" area whose upper limit was not fixed and tied to
the application's expectations.

What does one do in these sort of situations or have I missed
something conceptually?  I would like to be able to run an app without
telling the OS how much memory I need because I don't know how much.

Many thanks for all of your help now and in the past.  I remain
yours... Dark Hacker!



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ORGANIZATION:  BLETCH (Bletcherous League of Evil Twisted Computer Hackers)
UUCP:          kzin!speaker@mimsy.umd.edu  INTERNET:   jtn@potomac.ads.com
SPOKEN:        Dark Hacker                 PHONE:      (703) 243-1611

The Mythos of Dark Hacker:

"Controlled by the sinister and shadowy "suits" Dark Hacker now employs
the tools of computer science to free himself from the suit's will.
By day he is a lackey... but at night when the city sleeps he
becomes.... DARK HACKER!"
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