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Date: Mon, 16 Feb 2004 09:49:19 -0500
From: Christopher Faylor <cgf-no-personal-reply-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: 20040214 no fix for unzip, cygwin debugging howto?
Message-ID: <20040216144919.GE14904@redhat.com>
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References: <OFC6D4F950 DOT 8EC2BAD4-ON85256E3C DOT 001BC153-85256E3C DOT 001C5BD7 AT us DOT ibm DOT com>
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On Mon, Feb 16, 2004 at 12:09:44AM -0500, Thomas L Roche wrote:
>Thomas L Roche Mon, 16 Feb 2004 00:01:10 -0500
>> Unfortunately 20040215 came out while I was debugging 20042014.
>> Since you
>
>do not
>
>> claim to have done anything that might have actually fixed the
>> problem, the results obtained at
>
>> http://cygwin.com/ml/cygwin/2004-02/msg00705.html
>
>> are still relevant.

What you have discovered is that when memcpy is given a NULL pointer it
will case a SEGV.  What we need to discover is why the pointer was NULL.

When debugging problems like this and you see an error message, try to
find out where the error message came from and either set a breakpoint
there or, if you can, to save time, work back from that point to see if
you can see an obvious point to set a breakpoint where you can determine
what caused the NULL.

My strace change added additional debugging to try to determine why
cmalloc was returning NULL.  That's what needs to be debugged, not
the fact that cygwin eventually SEGVs.

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