S-Function（系统函数）为扩展Simulink® 的性能提供了一个有力的工具。以下下节阐述了什么是

S-Function，为什么可以使用S-Function，以及怎样编写自己的S-Function。-S-Function (system function) for the expansion of the performance of Simulink ®　provides a powerful tool. The following section describes what is under the S-Function, Why you can use the S-Function, and how to write your own S-Function.