int valvula_async_queue_waiters ( ValvulaAsyncQueue queue)

Allows to get current waiting threads on the provided queue.

queueThe queue that is being used to request the number of waiting threads.
The number of waiting threads or -1 if it fails. The only way to make the function to fail is to provide a null queue reference.

References valvula_mutex_lock(), and valvula_mutex_unlock().

Referenced by valvula_thread_pool_stats().