Re: [Boost-users] [condition] How to wait on multiple mutexes with OR semantics?

From: Maximilian Wilson (wilson.max_at_[hidden])
Date: 2007-11-16 11:25:12

On Nov 16, 2007 7:58 AM, Andrey Tcherepanov <moyt63c02_at_[hidden]>
wrote:

> Hello boosters,
>
> Let's say I have a 2 condition variables, and 2 threads that wait on them.
> I would like to collapse these 2 threads into 1 by making thread wait on
> *either* of  these conditions to lock their mutexes (it is not the same
> mutex). Is it possible to do, or I better change the logic under the hood?
>
>
It can be done, although it might be better not to. Use a counting semaphore
in the place of the two mutexes, and when a producer signals the semaphore
he should first set a global flag variable to indicate that he's done; when
the consumer acquires the semaphore he will check both global variables to
see which producer signalled him (or possibly both).

-Max

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