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From:	Chris Faylor <cgf AT cygnus DOT com>
Date:	Mon, 6 Dec 1999 23:48:15 -0500
To:	Mumit Khan <khan AT nanotech DOT wisc DOT edu>
Cc:	cygwin-developers AT sourceware DOT cygnus DOT com
Subject:	Re: (patch) enable signals in dynamically loaded Cygwin DLL
Message-ID:	<19991206234815.A21564@cygnus.com>
Mail-Followup-To:	Mumit Khan <khan AT nanotech DOT wisc DOT edu>,
	cygwin-developers AT sourceware DOT cygnus DOT com
References:	<199912070351 DOT VAA26863 AT mercury DOT xraylith DOT wisc DOT edu>
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In-Reply-To:	<199912070351.VAA26863@mercury.xraylith.wisc.edu>; from khan@nanotech.wisc.edu on Mon, Dec 06, 1999 at 09:51:31PM -0600

On Mon, Dec 06, 1999 at 09:51:31PM -0600, Mumit Khan wrote:
>Completely forgot about the synchronization used in makethread to avoid
>stack corruption, and that's why enabling signals for dynamically loaded
>Cygwin was crashing in newly created threads.
>
>This change removes the synchronization and uses dynamically allocated
>memory to the thread stub routine, which frees the memory. The overhead
>should be roughly the same, perhaps a tiny bit higher due to malloc's
>internal MT synchronization.
>
>A gotcha for future users of makethread -- if you pass a thread parameter,
>make sure it's not on the stack (which is the case currently, so it should
>be safe). 

Note that this probably affects tty initialization too.  It's not just
signals that are affected, it's any thread that is started during DLL
initialization.  Since CYGWIN=tty implies the creation of several runtime
threads, I assume that the problem is manifested there as well.

cgf

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