Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!oliveb!apple!jdevoto
From: jdevoto@Apple.COM (Jeanne A. E. DeVoto)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: Protection against memory limitation
Message-ID: <28559@apple.Apple.COM>
Date: 7 Apr 89 17:36:18 GMT
References: <80078GFX@PSUVM>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 20

In article <80078GFX@PSUVM> GFX@PSUVM.BITNET writes:
>[...]when a script calls a paint tool for example, it will fail because there
>is not enough memory left.
>
>Other than warning users that they need a full meg to use the stack, what
>could be done to 1) exit gracefully from a script if there is not enough
>memory to execute, 2) detect memory shortage before it creates any problem.

There is an undocumented function "the heapSpace" that will return
(approximately) the number of bytes remaining in the application heap.
It's possible to do a little preflighting with this function to see
whether you are dangerously low on memory before doing a memory-
intensive operation.

As I mentioned, the function is undocumented and I don't know whether it
will be supported in the future. However, it has been present on all
versions of HyperCard so far.

jeanne a. e. devoto
jdevoto@apple.com