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Date: Tue, 13 Jul 2010 06:58:36 +0100
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Subject: Re: Sending SIGUSR1 to thread in nanosleep causes segfault
From: Andy Koppe <andy DOT koppe AT gmail DOT com>
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On 12 July 2010 22:05, Corvus Corax wrote:
> Just to update some details.
>
> I am working with James Cotton on the OpenPilot project.
> We are trying to port the POSIX simulation port of FreeRTOS to cygwin.
>
> We run into issues with signal handling in cygwin 1.7.5 that are
> currently blocking our development, since every method to suspend a
> running thread via signals either causes:
>
> - random segfaults within Cygwin DLL.
> or
> - failure to execute the signal handler.

I'm afraid you're unlikely to get a quick and comprehensive answer,
because the Cygwin signal guru currently is on a well-deserved
vacation. Thanks for the testcases, hopefully they'll prove useful.

You could also try the latest snapshot from
http://cygwin.com/snapshots to see whether that makes a difference. A
debug version of the DLL is available there as well. And if you're
brave enough, you could try getting stuck into the Cygwin sources
yourself.

The trouble with Cygwin signals is that Windows provides practically
no support for them, so everything has to be manually mapped to
Windows concepts. Have a look at the Signals section of
http://www.cygwin.com/cygwin-ug-net/highlights.html for some of the
tricks. Obviously pthreads further complicate matters, and the sort of
thing you're doing here is not something that tends to get a lot of
use by "normal" programs, so shortcomings are quite likely.

Andy

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