Statically initialising pthread attributes in dynamic dlls.

[Dave Korn]

On 24/02/2010 04:52, Dave Korn wrote:

>   I think the answer lies here, in this comment in dll_dllcrt0_1:
> 
>>   /* Make sure that our exception handler is installed.
>>      That should always be the case but this just makes sure.
>>
>>      At some point, we may want to just remove this code since
>>      the exception handler should be guaranteed to be installed.
>>      I'm leaving it in until potentially after the release of
>>      1.7.1 */
>>   _my_tls.init_exception_handler (_cygtls::handle_exceptions);
> 
>   Well, it may or may not already be installed, depending whether we got here
> via dlopen or whether this is a statically-linked DLL being initialised at
> process startup, and if it is already installed, it's not at the front of the
> list.  So I figure the best bet would be to replace this call with a local
> stack-frame-based exception registration record, which we'll unlink if we
> return.  IOW, just the same thing as those OS-registered SEH frames are doing
> when they unwind.  I'll report back later if it works.

  Yeh, that works nicely.  Here's what I tested, along with a couple of extra
test cases I used to check whether exception handling was still working before
and after the dlopen call.  With the current state of HEAD, the first one
works (by which I mean "prints 'sig 11' forever" and the second one fails (by
which I means reaches some sort of exit without hitting the signal handler at
all).  With the attached diff, they both work (as does the original unmodified
testcase).

  This is just a brain dump because I'm off to bed now, hence no change log,
and there's still commented-out stuff and inadequate commenting, but I figured
 I may as well let everyone know what I found out.  'night all!

    cheers,
      DaveK

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