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

For performance reasons, the POSIX API allows the OS to wake up your thread even if the condition has not been fulfilled (that's called a spurious wakeup).