Path: utzoo!dciem!client1!mmt
From: mmt@client1.DRETOR.UUCP (Martin Taylor)
Newsgroups: comp.sys.mac.hypercard
Subject: Memory loss when browsing
Message-ID: <2663@client1.DRETOR.UUCP>
Date: 15 Nov 89 23:32:52 GMT
Organization: DCIEM, Toronto, Canada
Lines: 26


General question:  under what circumstances should a stack be expected
to change its size (i.e. produce free memory in stack) when it is being
browsed at userlevel 1?  It seems to me this should never happen, but it
does, and to an alarming degree.

Particular example:  I have a stack that consists mainly of a whole lot
of popup fields on a painted background (card fields, not background
fields).  The fields contain between 4 and perhaps 40 words, and their
programming is identical (except for the name of the field being popped up).
After compacting the stack (free memory = 0) the userlevel is set to 1.
A button is clicked that pops up one of the fields.  Set the userlevel
to 5 and look at the stack info--free memory 22K!  (Lots of disk action
accompanying the popup event).  But do this with another button (and
on one occasion out of perhaps 20 with the same one) and zero free memory
is added to the stack.  Other buttons give different amounts of added
free memory, and the loss seems to be cumulative.  If the same 22K-losing
button is re-used, it does not lose any more space, but other space-losing
buttons do lose extra space.  After a bit of browsing, my stack had lost
almost 100K.

This is not nice.  Is its cause known?  Is a work-around known?
-- 
Martin Taylor (mmt@zorac.dciem.dnd.ca ...!uunet!dciem!mmt) (416) 635-2048
If the universe transcends formal methods, it might be interesting.
     (Steven Ryan).