Writing S-Functions

Level 1 Versus Level 2 S-Functions

The original S-function interface has been dubbed the "Level 1" API. As the capabilities of Simulink grew over the years, the S-function API was rearchitected into the more extensible "Level 2" API. This allows S-functions to have all the capabilities of a full Simulink model (except automatic algebraic loop identification and solving) and to grow as Simulink grows.

Creating Fortran S-Functions

Creating Level 1 Fortran S-Functions