What is the use of urgent pointer in TCP segment?

For accommodation out of band signaling, TCP permits the sender to identify data as urgent, implies that the receiving program must be notified of its arrival as rapidly as possible, regardless of its position into the stream. For this reason Urgent pointer field is utilized. The mechanism employed to mark urgent data while transmitting this into a segment contains URG code b t and the URGENT POINTER field. While the URG bit is set, the urgent pointer identifies the position into the segment where urgent data ends.