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Re: attn: ghudson; FSFS and multi-threading on Unix broken?

From: Sander Striker <s.striker_at_striker.nl>
Date: 2005-04-05 19:44:05 CEST

Greg Hudson wrote:
> On Tue, 2005-04-05 at 11:57, Ryan Bloom wrote:
>
>>ok, the global_mutex (that's the real name), allows you to specify the
>>lock mechanism, just as apr_process_lock does, so that is easily
>>resolved.
>
>
> Okay, that's much closer to what we want.
>
> But we don't want Subversion to be in the business of picking a locking
> mechanism. That's why we used apr_file_lock() in the first place. We
> want APR to choose a mechanism, but we want it to work over network
> filesystems. If we ask APR to choose the default mechanism, it looks
> like APR on Unix will choose flock/sysv/fcntl/pthreads/semaphores in
> that order, which will work/fail/work/fail/fail respectively.
>
> Worse, on Windows, it appears the locking mechanism is ignored (!) and a
> mutex is used in all cases. I can only assume that this mutex is
> machine-specific. We want to continue using LockFileEx() under Windows.
>
> I'm guessing what we'll wind up doing is using apr_file_lock() under
> Windows, and a global mutex with the fcntl mechanism specified under
> Unix. But obviously APR is not providing quite what we want here.
>
> (I'm looking at APR_0_9_BRANCH if that's relevant.)

Meta reply: Greg, you are aware that apr is in SVN nowadays?

  http://svn.apache.org/repos/asf/apr/apr/branches/0.9.x/

Sander

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Received on Wed Apr 6 18:06:17 2005

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