Consider the following code to initialize the concurrent Michael and Scott Queue from class.
void Queue_Init(queue_t *q) {
node_t *tmp = malloc(sizeof(node_t));
tmp-next = NULL;
q-head = q-tail = tmp;
pthread_mutex_init(&q-headLock, NULL);
pthread_mutex_init(&q-tailLock, NULL);
}

Why does an empty queue have a node allocated?

Question

Consider the following code to initialize the concurrent Michael and Scott Queue from class. 
 void Queue_Init(queue_t *q) {
   node_t *tmp = malloc(sizeof(node_t));
   tmp->next = NULL;
   q->head = q->tail = tmp;
   pthread_mutex_init(&q->headLock, NULL); 
   pthread_mutex_init(&q->tailLock, NULL);
}

Why does an empty queue have a node allocated?

Accepted Answer

The node acts as a dummy node to ensure that the head and tail locks are always for different nodes.

Answer

Without the dummy node, our code might crash when we add something to the queue later, and we would rather that happen now to deal with it.

Answer

This is how all data structure are initialized in C.

Answer

This is an unnecessary bug and should not be there.

Answer

The dummy node is the place where we will store the locks.

Crowdly

Consider the following code to initialize the concurrent Michael and Scott Queue...

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