Waiting On A Condition Variable (Cont.)

The "pthread_cond_wait" function expects the mutex passed to it to be locked.

When the function is invoked the mutex is unlocked, and then the calling thread blocks until the condition variable is signaled.

When the condition variable is signaled, the "pthread_cond_wait" locks the mutex again, and then returns.

When we cover the whole scenario, we'll see why this mutex is used here.