Simulink Reference

User-Defined Functions

The User-Defined Functions library contains blocks that allow you to define the function that relates inputs to outputs..

Block Name	Purpose
Fcn	Apply a specified expression to the input.
MATLAB Fcn	Apply a MATLAB function or expression to the input.
S-Function	Access an S-function.
S-Function Builder	Builds a C MEX S-function from specifications and code that you supply.

Sources

Blocksets and Toolboxes