DESCRIPTION

insque() and remque() manipulate queues built from doubly linked lists. The queue can be either circular or linear. Each element in the queue must be of the following form:

struct qelem {
	struct qelem   *q_forw;
	struct qelem   *q_back;
	char            q_data[];
};

The first two elements in the struct must be pointers of the same type that point to the previous and next elements in the queue respectively. Any subsequent data in the struct is application-dependent.

The insque() function inserts elem into a queue immediately after pred.

The remque() function removes elem from the queue.

These functions are not atomic unless that machine architecture allows it.