Writing S-Functions

Building an Ada S-Function

To use your Ada S-function with Simulink, you must build a MATLAB executable (MEX) file from the Ada source code for the S-function. Use the MATLAB mex command to perform this step.

The mex syntax for building an Ada S-function MEX file is

• mex [-v] [-g] -ada SFCN.ads
  

where SFCN.ads is the name of the S-function's package specification.

For example, to build the timestwo S-function example that comes with Simulink, enter the command

• mex -ada timestwo.ads
  

Ada Compiler Requirements

To build a MEX file from Ada source code, using the mex tool, you must have previously installed a copy of version 3.12 (or higher) of the GNAT Ada95 compiler on your system. You can obtain the latest Solaris, Windows, and GNU-Linux versions of the compiler at the GNAT ftp site (ftp://cs.nyu.edu/pub/gnat). Make sure that the compiler executable is in MATLAB's command path so that the mex tool can find it.

The GNAT Ada95 compiler package used to include gnatdll.exe, a tool for building DLLs on Windows. This tool, which is required to build Ada MEX files on Windows, now comes as part of a separate gnatwin package containing Windows-specific files. If you want to build Ada S-functions on a Windows system, you must download and install the gnatwin package as well as the GNAT Ada95 compiler.

Writing Callback Methods in Ada

Example of an Ada S-Function