Re: [Qemu-devel] [PATCH] coroutine: Fix win32 variant for older mingw32 compilers

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-11-21 20:11, Stefan Weil wrote:
> Am 21.11.2012 15:38, schrieb Paolo Bonzini:
>> Il 21/11/2012 15:33, malc ha scritto:
>>>>>>> Leaking leader is a bit bad, but it looks ok for 1.3.
>>>>> Hmm. A TLS destructor is apparently not available. Is there some "on
>>>>> thread termination" callback mechanism on Windows? Didn't find one on
>>>>> first glance.
>>>>>
>>> Dlls receive something like THREAD_DETTACH in it's startup routine or
>>> something like that if my memory serves me.
>> Only DLLs.
>>
>> But this sounds like deja-vu.  I'm pretty sure in the past we just
>> decided that this compiler is not supported (of course it's bad that
>> it's silent).  Stefan, do you remember the details?
>>
>> Paolo
> 
> Debian cross works with -mthread.The issue was discussed here:

Yep, works here as well.

With this knowledge, why not convert the TLS usage in
qemu-thread-win32.c as well? That's what motivated me to go this path.

> 
> https://bugs.launchpad.net/qemu/+bug/932487
> 
> Jan, I don't think your patch should be applied.

I agree, but we need a different solution for this subtle failure.

> 
> Current MinGW / MinGW-w64 compilers work, so those users
> which compile and use QEMU on Windows won't have a problem.
> With MinGW-w64, it is even possible to compile QEMU with nearly
> no warnings :-)
> 
> Debian cross development is full of difficulties. Passing an extra
> compiler option like -mthread is only one of these difficulties.
> I updated http://wiki.qemu.org/Hosts/W32, so anybody who really
> wants to run cross compilations on Debian can get more information
> there.
> 
> We could add a check to configure and add -mthread automatically.
> Up to now, there was no consensus whether this is wanted because
> -mthread adds a library to QEMU's dependencies.

As the alternative to this is a crashing QEMU, I doubt there is much to
discuss.

Do we know which mingw version is fine without -mthreads? Or do we have
to test this during configure?

Jan

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