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Date: Fri, 14 Sep 2001 21:34:07 +0400
From: egor duda <deo AT logos-m DOT ru>
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Message-ID: <142188273973.20010914213407@logos-m.ru>
To: Jonathan Kamens <jik AT curl DOT com>
CC: cygwin-developers AT cygwin DOT com
Subject: Re: Useful details about the Make SEGVs
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Hi!

Friday, 14 September, 2001 Jonathan Kamens jik AT curl DOT com wrote:

JK> Do you think I should try rerunning the "make -j2" under strace?

probably. strace is good when you've partially identified the cause of
the problem, and want to trace how it comes that info in pipe is lost.
The power of strace is that you can add your own debugging output in
arbitrary places of dll code and see, for example, how many bytes are
in pipe. than you grep an strace and see where those bytes gone.

JK> How about running it with a cygwin1.dll compiled with malloc debugging
JK> (ouch! that'll hurt)?

that'll certainly hurt :) i afraid that we won't hear anything from
you for a while... malloc debugging is useful when you see that heap
is corrupted, which is almost always seen immediately at crash time
from the stack trace. the problem with heap corruption is that heap is
corrupted long before the crash, so you're not able to find the cause
of the problem using normal debugging methods.

in 'make -j2' case it doesn't look like heap corruption.

JK> Incidentally, is it possible to run an application using a cygwin1.dll
JK> with malloc debugging but to run gdb on the application using a
JK> cygwin1.dll *without* malloc debugging?  Gdb seems very difficult to
JK> use when malloc debugging is enabled.

yes. that's what separate c:\cygdeb\ directory with its own stable
non-debugging version of cygwin1.dll is used for.

Egor.            mailto:deo AT logos-m DOT ru ICQ 5165414 FidoNet 2:5020/496.19