When the selection of the routine to assign to a function pointer is based on a particular piece of data, such as the protocol handling the data or the device driver a given packet is received from, it is easier to derive the routine.

• 当常式的选择去分配一个函数指针是基于以一组特别的数据,像是操作数据或者一个给定信息包被设备驱动接收的协议,源自常式是比较容易的。