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Subject: Re: [boost] [thread] countdown_latch
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2013-04-27 03:05:40

Le 22/04/13 10:16, Michael Marcin a écrit :
> On 4/21/2013 11:30 PM, Vicente J. Botet Escriba wrote:
> Back on topic of latches and barriers.
> I was reading up on Java's CyclicBarrier and found its await return
> value pretty interesting and probably fairly free to implement.
> "...each invocation of await() returns the arrival index of that
> thread at the barrier."
> "the arrival index of the current thread, where index getParties() - 1
> indicates the first to arrive and zero indicates the last to arrive."
> To do this in boost::thread::barrier you would just have to cache
> m_count right after the decrement and return it instead of the current
> true/false.

Yes, boost::barrier return true for the last wait. The change would be
quite simple, but what would be he utility of such an index?

I have implemented a first prototype of a latch class that could be used
also as a barrier. I don't know if the name is the good one then.
I have also implemented a completion_latch class that is able to call a
function when the counter reaches zero. I'm not satisfied with the
current implementation as it needs a lot of synchronization.

The change set is To
see the sources, you would need to update the trunk or to take a look at

Please let me know what do you think.


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