Re: [boost] [thread] countdown_latch

On 5/12/2013 6:49 AM, Rob Stewart wrote:

On May 11, 2013, at 5:29 PM, Gaetano Mendola wrote:

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On 21/04/2013 12.54, Rob Stewart wrote:

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I'd prefer to create a barrier class and, in your example, it would release waiting threads when two are blocked behind it. IOW, you'd create a barrier for two threads and both thread_proc() and the constructor would wait() on the barrier. Once both threads have called wait(), they are both released. (I plan to present that at C++ Now, this year.)

As said that's create a not needed "wait" on the thread body, what the OP (and me for the matter) needs is that *only* thread creator is blocked waiting for the threads to arrive at certain point of the execution.

It seems to me that wait is inconsequential relative to the cost of creating a thread. If this were part of the thread creation process, an option to thread's constructor, say, there would be some convenience, but the performance difference doesn't seem worthwhile. Have I missed something?

The created thread is already executing when it gets to the latch. Why would you want to introduce synchronization, and potentially block the thread, where none is needed?