Message-ID:	<39B28CA5.14799CC8@user.rose.com>
From:	April <awhite AT user DOT rose DOT com>
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Newsgroups:	comp.os.msdos.djgpp
Subject:	tracking an elusive crash
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Date:	Sun, 03 Sep 2000 12:38:46 -0500
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I am working with btree code based on a text book.  I get an elusive
crash that I cannot track down nor get any useful info post-crash.

djgpp gcc version 2.95.2 19991024
win95

The worst crash reboots the computer, the second worst gives a fatal
error 'you program has commited an illegal instruction'.  Obviously in
both cases there is no call stack to symify.

I use a configuration file page size, and this is what makes the crash
elusive.  If I use 512 bytes or 2048 bytes, the program can add about
17000 words to the tree (with duplicates ignored), and then delete 16999
(I leave one for testing), without a problem.

If I use a page size of 1024 (or just recently tried, 4096), I get the
fatal crash during the delete test, several 100 (maybe a 1000 or more)
words later.

I have tried to run the program in dos mode (ie. booted to dos), but the
GPF gives no callstack, and if I can believe the IP address, when I
locate it in the map file I finaly created, it is inside
libc.a(exceptn.o).

I have tried to increase my internal buffer that corresponds to the page
buffer, but too no avail; I tried to allocate larger memory blocks and
put an indicator before/after and check for those upon release, too no
avail.  I tried to put an indicator at the start of all of my file
blocks and verify this upon any read process, to no avail.

HELP!

What can I try?  I though it might be from redirecting a large file for
input and producing a large redirected stdout output, so I replaced the
input with a direct file read - it still crashed.

Suggestions?

April

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