> < ^ Date: Tue, 27 Jul 1993 07:33:24 +0200
> < ^ From: Martin Schoenert <martin.schoenert@math.rwth-aachen.de >
< ^ Subject: Re: Problem in FactorsInt

Hiroshi Matsuyama writes in his e-mail message of 1993/07/23
I use Gap on SVR4/386 (Japanese version) with intel 80486/60MHz.
I tried factoring the 17-th repunit as follows.
But Gap does not factorize it, and exits to shell.

gap> FactorsInt((10^17-1)/9);
Gasman: last bag of type str and size     4 has overwritten the free bag.

Of course, Gap on Sparc station and Gap386.exe
can factor (10^17-1)/9 corrrectly.
This implies that the problem is in the machine (NEC) or
in the Japanes version of UNIX SVR4/386.

What the message means ?
Please give me any advice.

This is a message from Gasman -- GAP's storage manager. Each time an
object is allocated Gasman checks that the word behind the previously
allocated object has not been overwritten. This check failed in the
example above. I.e. the last bag, which was a string with 3 characters
(plus a terminating '\0' character) has overwritten the following word.

Does the executable work for other problems? Or does it fail for any
nontrivial computation? Which C compiler did you use? Have you compiled
GAP without the optimizer (i.e., without the '-O' option)?

Please send your answer to 'gap-trouble@samson.math.rwth-aachen.de'. If
anything interesting comes out of this I will summarize in the GAP


-- .- .-. - .. -.  .-.. --- ...- . ...  .- -. -. .. -.- .-
Martin Sch"onert,   Martin.Schoenert@Math.RWTH-Aachen.DE,   +49 241 804551
Lehrstuhl D f"ur Mathematik, Templergraben 64, RWTH, 52056 Aachen, Germany

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