Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!husc6!bloom-beacon!athena.mit.edu!lwvanels
From: lwvanels@athena.mit.edu (Lucien Van Elsen)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Allocating arrays?
Message-ID: <9127@bloom-beacon.MIT.EDU>
Date: 6 Feb 89 17:34:55 GMT
References: <867@fornax.UUCP>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: lwvanels@athena.mit.edu (Lucien Van Elsen)
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Organization: Massachusetts Institute of Technology
Lines: 26

In article <867@fornax.UUCP> you write:
>Here's a simple question I'd appreciate some advice on.  I'm using LightSpeed
>Pascal 2.0 (great product, by the way, Rich), and I want to dynamically
>allocate arrays of structured types, with the number of elements in the
>arraynot known until the array is actually allocated.

I solved a similar problem by declaring a type that's an array as large
as you might ever possiblly want it, and then creating a handle in the
program that's only as large as you need.  I.E.

type comparray : array[1..maxnum] of complextype;
compptr : ^comparray;
comphan : ^compptr;

myhandle := comphan(Newhandle(sizeof(wanted*sizeof(complextype))));
(where wanted is the desired number of elements in the array)

You have to take care that you never reference an index larger than
the number you have allocated- there's nothing to stop you from going
past the end of the handle you have allocated.  However, it is
possible to dynamically grow/shrink the array while the program is
running using SetHandleSize(myhandle,newnum*sizeof(complextype)).
Hope this helps!
Lucien Van Elsen
Internet:lwvanels@athena.mit.edu or lve@wheaties.ai.mit.edu
UUCP: ...!mit-eddie!mit-athena!lwvanels