Path: utzoo!attcan!uunet!husc6!mailrus!ncar!tank!nucsrl!bob
From: bob@eecs.nwu.edu (Bob Hablutzel)
Newsgroups: comp.sys.mac.programmer
Subject: Re: What is this system error??
Message-ID: <10050045@eecs.nwu.edu>
Date: 12 Nov 88 03:10:27 GMT
References: <5813@ecsvax.uncecs.edu>
Organization: Northwestern U, Evanston IL, USA
Lines: 22



... Stuff ...
> The bomb box say there has been a system error and mentions 33.
> What is the 33??

... More stuff ...


System bomb 33 is the dreaded negZcbFreeErr. Simply put, a heap thinks that
it has negative amounts of memory free, a condition which simply cannot 
happen in the normal course of human events. Probably you are writting
into some memory you shouldn't touch, either via a dangling pointer, invalid
dereference, or whatever. The only way I can think of finding the problem with
Discipline is to catch every trap, and check the state of the heaps before and
after each trap. While it is not neccessarily a trap which is trashing the 
heap, traps happen often enough that if you can say "at trap x it's ok, and the
next trap, y, reports a problem", you have a smaller area to look in.

Have fun - these can be the worst kinds of errors to have to track down.

Bob Hablutzel	BOB@NUACC.ACNS.NWU.EDU