Why do you need a while loop while waiting for a condition variable

Question

Say you have this code

pthread_mutex_lock(&cam->video_lock);
while(cam->status == WAIT_DISPLAY) // <-- Why is this a \'while\' and not an \'if\'         


        

Answer 1

It is recommended that all threads check the condition after returning from pthread_cond_wait because there are several reasons the condition might not be true. One of these reasons is a spurious wakeup; that is, a thread might get woken up even though no thread signalled the condition.

Source : Spurious wakeup