Le 22/04/13 10:16, Michael Marcin a écrit :
On 4/21/2013 11:30 PM, Vicente J. Botet Escriba wrote:
Hi,
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 https://svn.boost.org/trac/boost/changeset/84055. To see the sources, you would need to update the trunk or to take a look at https://svn.boost.org/svn/boost/trunk/boost/thread/ Please let me know what do you think. Best, Vicente