From schumann@wow.arc.nasa.gov Thu Jan 17 08:03:12 2002
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Date: Wed, 16 Jan 2002 23:03:10 -0800 (PST)
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From: schumann@email.arc.nasa.gov
To: prolog@swi.psy.uva.nl
Cc: schumann@email.arc.nasa.gov
Subject: [SWIPL] Crash in Garbage collection

Hallo,

we are developing a large program synthesis system (~30k lines) using SWI.
After a recent change, we get crashes during garbage collection.
The system works seemingly fine when the gc is turned off.
This problem occurs on 3.4.X and 4.0.11 (didn't try out the new version yet),
both on sun solaris and linux (x86 and PPC). 
We are using the basic Prolog set (no GUI, data base,...) but lots of meta
predicates. Any attempt to turn on traceing or write_ln's makes the error
go away (of course :-( ). We could narrow down the problem to ~1000 lines 
of Prolog, but could not find anything suspicious.
My questions:
* does this kind of error ring a bell (I browsed the archive, but could not
	find a match)
* is there a C-routine which dumps (parts) of the stacks in a readable manner
(environments, choicepoints, terms on the global stack, etc.) so we could
perhaps find how the terms close to the problem look like (and where/how
they were created)?

* any advice or tricks how to tackle such a problem?

thanks in advance
-johann schumann
RIACS / NASA Ames

