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From: Jim.Spencer@p510.f22.n282.z1.fidonet.org.org (Jim Spencer)
Newsgroups: comp.sys.mac.programmer
Subject: How to malloc memory VERY dynamically and not out of app heap?
Message-ID: <669949449.1@mmug.fidonet.org.org>
Date: 25 Mar 91 04:03:29 GMT
Sender: UUCP@mmug.fidonet.org.org
Lines: 18


John T. Nelson writes in a message to All

JTN> Now... in order to handle those BIG files this means that I need 
JTN> an app size that's extremely large (several megabytes) but that 
JTN> means I cripple the application because then it won't run on 
JTN> smaller Macs with perhaps only two meg of memory. If I set the 
JTN> app size too small then it doesn't run on those big files. It 
JTN> would be nice to newPtr my space from a "free" area whose upper 
JTN> limit was not fixed and tied to the application's expectations. 
JTN> 
JTN> What does one do in these sort of situations or have I missed 
JTN> something conceptually? I would like to be able to run an app 
JTN> without telling the OS how much memory I need because I don't 
JTN> know how much.

What you are missing is that if you really plan to handle really big files, on the order of several megabytes, you need to come up with a way to only read part of the file into memory at a time.  Even those with lots of RAM won't go for a text processer which needs really huge amounts of memory just so the entire file can be in RAM at the same time.