Specify port types in s-function blocks

Question

I'm building my first s-function block from compiled C code. Everything is going fine, except that the s-function block demands that its interface variables are of type double, even though the underlying C interface variables are not. The block raises an error if I connect a boolean signal to the input and try to run.

I'm getting the variables in the code by calling ssGetInputPortSignal and ssGetOutputPortSignal, and casting the void pointers they return into the correct pointer types.

How do I configure the types of an s-function block's parameters in Simulink?

Answer 1

Take a look at ssSetInputPortDataType. Needs to be called in the S-Function mdlInitializeSizes function. In your case you'll need something like:

ssSetInputPortDataType(S, 0, SS_BOOLEAN);

Assuming the input port is the first one and you're not concerned about the return value.

The function for the outputs is ssSetOutputPortDataType, with identical use.