The functions are cancellation points and might cause a pending signal to get delivered in a threaded environment when the program is not expecting it.
这些函数都是可撤销点，并且可能导致在线程环境中产生一个该程序并不期望的挂起信号。
2
The concept of network control was extended to let digital switches communicate with databases (known as Service Control Points) and signal processing systems (Intelligent Peripherals).
网络控制的概念被扩展到了让数字交换机与数据库（称为服务控制点）和信号处理系统（智能外设）通信。
3
CSCF handles SIP registration of the end points and process SIP signal messaging of the appropriate application server in the service layer.