In computer programming , a suspended process that waits for a certain kind of event to occur , it is then automatically actuated , performs its job and either terminates or suspends itself in wait for the next event 程序設計中的一種被掛起的進程,它等待某種事件發生,然后自動地被激活、執行作業,然后終止或將自身掛起,等待下一事件。