Thanks for the quick reply. Using conditon variables sounds quite heavy. You need to instantiate a mutex, a condition variable and a flag... Would there be anything wrong with instantiating a semaphore from the interprocess library to provide inter-thread synchronization? By the way, why isn't there any semaphore available in the thread library? Jean On 2-Apr-09, at 9:25 PM, Sohail Somani wrote:

Jean-Sebastien Stoezel wrote:

...

Hi,

I need to synchronize 2 threads, that is once one is done doing something, it should activate another thread that had been waiting in a pending state. I see the thread library offers mutexes and nothing else. I guess mutexes would do, but I do not believe I should use mutexes for my application. Mutexes are supposed to provide mutual exclusion when critical data is accessed. Semaphores should be used for what I want to do.

You can use condition variables for signalling:

http://www.boost.org/doc/libs/1_38_0/doc/html/thread/synchronization.html#th...

-- Sohail Somani http://uint32t.blogspot.com

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Jean-Sebastien Stoezel wrote:

Thanks for the quick reply. Using conditon variables sounds quite heavy. You need to instantiate a mutex, a condition variable and a flag... Would there be anything wrong with instantiating a semaphore from the interprocess library to provide inter-thread synchronization? You can use a semaphore from the interprocess library to provide inter-thread synchronization. An interprocess semaphore is a thin wrapper around a posix semaphore if BOOST_INTERPROCESS_POSIX_SEMAPHORES is defined. Otherwise, a semaphore is emulated with a mutex and a condvar.

By the way, why isn't there any semaphore available in the thread library?

The boost.Crypto library is going to provide some. BR, Dmitry