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From: "Chris January" <chris AT atomice DOT net>
To: "Boris Schaeling" <boriss AT web DOT de>
Cc: "Cygwin AT Cygwin DOT Com" <cygwin AT cygwin DOT com>
Subject: RE: Bug in g++: Testcase exits with segmentation fault
Date: Tue, 14 Jan 2003 17:01:15 -0000
Message-ID: <LPEHIHGCJOAIPFLADJAHMEFIDDAA.chris@atomice.net>
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> The testcase attached to this mail compiled with g++ 2.95.3-10 or g++ 3.2
> 20020927 under Cygwin 1.3.18 exits with segmentation fault. It seems to be
> an error in g++ as the testcase doesn't work under Linux either.
> Can anyone
> help or do I have to report this error to the GCC website?
>
> BTW I found two ways to make the testcase work:
> 1) Change line 64 (and 70 respectively) and use "observer
> *Observer" instead
> of "std::list<observer>". I compiled the testcase with STLport-4.5.3 under
> Linux to see if it's a bug in the Standard Library but got again
> segmentation fault.
> 2) Remove line 75 which is a simple "poll(NULL, 0, 2000)". It
> works without
> this line but I don't know why.

The bug is actually in your testcase.
The line:
	Observers.push_back(observer());
creates a temporary observer object. So when the line
	observer::observer() { Select.give(this); }
calls give(), it leaves a dangling pointer.

Chris


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