[openamq-dev] Regarding amq_client_session_wait

[blog]

On Wed, 2007-12-19 at 11:56 +0100, Martin Sustrik wrote:
> > This is the problem: the call to amq_client_session_wait is a blocking
> > call.  Blocking calls prevent me from controlling my application.  How
> > do I cleanly interrupt the blocking call ?
> 
> Still not sure what the problem is. In your preferred code below the 
> sem_wait is a blocking call. What's the difference between calling 
> amq_client_session_wait to wait for a message and calling sem_wait?
> 
> Martin

The difference is that I can signal the semaphore from elsewhere in my
code (or in the case of a named semaphore, from anywhere), and allow the
thread to exit cleanly. This would also allow me to close the session
and connection properly, and also clean up other resources.


> 
> >>> thread_func()
> >>> {
> >>>    semaphore sync("Unique_name");
> >>>    initialize_semaphore(sync, NOT_SIGNALED);
> >>>    amq_client_session_wait (session, sync); //non-blocking call
> >>>
> >>>    semaphore_wait(sync);// blocks until signaled - very efficiently.
> >>>    if(amq_client_session_basic_arrived_count (session)) 
> >>>    {
> >>>      while (content && run)
> >>>      {
> >>>        //  process content
> >>>        content = amq_client_session_basic_arrived (session);
> >>>      }
> >>>    }
> >>>    else
> >>>    {
> >>>       // something else happened on the sync object
> >>>       // perhaps the app wants the thread to shutdown,
> >>>       // either way, we have fallen out of the blocking call
> >>>    }
> >>> }
> _______________________________________________
> openamq-dev mailing list
> openamq-dev at lists.openamq.org
> http://lists.openamq.org/mailman/listinfo/openamq-dev