An S-function is a computer language
description of a Simulink® block written in MATLAB®, C, C++, or Fortran. C, C++, and Fortran
S-functions are compiled as MEX files using the
mex utility. See Build C MEX Function. As with other MEX files, S-functions are dynamically linked
subroutines that the MATLAB execution engine can automatically load and
You can implement your S-functions using one of these ways:
Level-2 MATLAB S-function — Provides access to a more extensive set of the S-function API and supports code generation.
C MEX S-function — Enables you to implement your algorithm as a C MEX S-function or write a wrapper S-function to call existing C, C++, or Fortran code.
The S-Function Builder — Provides a graphical user interface that is used to generate new S-functions or incorporate existing C or C++ code without interacting with the S-function API.
The Legacy Code Tool — Provides a set of MATLAB commands that helps you create an S-function to incorporate legacy C or C++ code.
Learn how S-functions work.
Learn key concepts needed to write different types of S-functions.
Implement S-function callback methods.
Compare and contrast features supported by different types of S-function implementations.