Using S-Function Builder with data type imported from a nested namespace

I want to create an S-Function using data types defined in a header file. The header file contains structs within a namespace. I have imported the data types into a data dictionary via

Simulink.importExternalCTypes('sample.hpp', 'DataDictionary', 'sample_dict', 'Language', 'C++', 'DataDictionarySection','ArchitecturalData');

The dictionary, sample_dict.sldd, contains my data type my_data and includes the following properties:

• Data scope: Imported
• Header file: sample.hpp
• C++ Namespace: foo::bar

I created a Simulink model sample_model, in which I want to create an S-Function with the S-Function Builder block. I populated a bus with dummy data and selected bus: my_data as the data type for the input and output of the S-Function.

If I try to build the S-Function, I get the error "error: 'my_data' does not name a type"... and later "error: 'my_data' was not declared in this scope; did you mean 'foo::bar::my_data'?". I attemped using namespace foo::bar in the #includes section, but that did not fix my issue. Can I use the data type from the namespace in my S-Function interface? If so, how?

The attachment includes the sample header, data dictionary, and model.

Answer 1

[Aditya]

Hi PJ,

Simulink S-Function Builder can’t find your struct type because it’s defined in a C++ namespace (foo::bar::my_data), but Simulink tries to use just my_data.

Following steps might help you to resolve the issues:

1. Use the fully qualified name:In S-Function Builder, set the input/output data type to Custom and enter foo::bar::my_data.
2. Set language to C++:In S-Function Builder settings, select C++ as the language and ensure the source file extension is .cpp.
3. Include your header:Add #include "sample.hpp" in the S-Function Builder includes.

You can aslo refer to the following documentation for more details :

https://www.mathworks.com/help/simulink/slref/sfunctionbuilder.html

[PJ]

@Aditya Your recommended Step 1 does not work. The S-Function Builder does not accept the double-colon. It reduces foo::bar::my_data to foobarmy_data. I have performed Steps 2 & 3 but still get errors.