How can I define an S-Function Outport as bus typed?

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MathWorks Support Team 2024-9-18，0:00

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回答： MathWorks Support Team 2024-9-19，12:03

I want to create an S-Function with a bus-typed Outport. The name of the bus type shall be provided via mask parameter as shown below.

In the current implementation, I am using the code below to assign the mask parameter value to the bus type information

char* busName;

    /* Bus object name is passed in as a parameter */
    ssGetSFcnParamName(S, 1, &busName);
    ssSetBusOutputObjectName(S, 1, busName);

/* Output nonvirtual bus */
ssSetBusOutputAsStruct(S, 1, true);
This however results in the error below
Variable or object 'BusName' in scope from 'ModelName/BlockName/S_Function' is not a Simulink.DataType object
The error refers to 'BusName' which is actually the name of the mask parameter rather than its value. Is it possible to define the Outport's bus type via mask parameter?

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Answer 1

MathWorks Support Team 2024-9-18，0:00

0
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Before implementing the desired behavior, please consider these limitations

The example block uses a char array, which is not allowed. For a list of supported types, please see this documentation link: https://www.mathworks.com/help/simulink/ug/data-types-supported-by-simulink.html
Instead of character arrays, Simulink supports utilization of Strings, but not if the target block is an S-Function: https://www.mathworks.com/help/simulink/ug/simulink-strings.html#mw_588e9a27-6f3e-48f4-ad7a-4c66f6b0526c

By following the instructions below, you can define the bus type via block mask parameter

create a Simulink.Bus object with the desired name, e.g. "outputBusName"
inside the block mask, add a DataTypeStr element
open the DataTypeStr's Type options via the pencil icon,
navigate to User-defined tab and select "Bus"
navigate to the mask and add the bus name to the new parameter field as "Bus: outputBusName"
adjust the implementation your S-Function as follows

    //write the value of the DataTypeStr to busname
    ssGetSFcnParamName(S, 1, &busName); 
    ssSetBusOutputObjectName(S, 1, busName);
    
    // register bus name as valid data type
    DTypeId dataTypeIdReg; 
    ssRegisterTypeFromParameter(S, 1, &dataTypeIdReg);
    
    // set data type
    ssSetOutputPortDataType(S, 1, dataTypeIdReg);
    ssSetBusOutputAsStruct(S, 1, true);