在程序设计中，用于连接两个分离例程的程序代码。它能够在例程之间传递数值和或控制权。 In programming, code that connects two separately coded routines and passes values and/or control between them.
计算机程序、例程、或子例程内的具有如下功能的任何指令，执行这条指令后控制权将不再由该计算机程序、例程、或子例程行使了。 Any instruction in a computer program, in a routine, or in a subroutine after the execution of which control is no longer exercised by that computer program, that routine, or that subroutine.