Return structure from setExternalInputsFcn

I am using simulink.compiler.setExternalInputsFcn to declare a callback function which returns a value to each input port at each timestep.

Something like

simin = similink.compiler.setExternalInputsFcn(simin, inputsFcn)

If the return value from this function is scalar, or an array this seems to work fine. However, I want to return a structure, which will be mapped to a bus in Simulink.

I create the bus type in my model data dictionary, and set it as the type for the input port. I declare the callback like so

function v = inputsFcn(id, t)

v = struct('a',1,'b',2,'c',3);

end

But trying to run this gives the following line in the error...

ExternalInputsFcn could not be enabled due to the following incompatibilities:

and further down...

Caused by:

Error using Simulink.Simulation.internal.DesktopSimHelper

The data type of root inport 1 is not of a supported type.

Is this not allowed???

[Alvaro]

Could you elaborate as to why you are trying to pass a struct into your inport?

I couldn't get simulink.compiler.setExternalInputsFcn to take a struct either but I am getting this error

The dimensions, data type or complexity of the return value from the ExternalInputsFcn for port 1 are incorrect.

Perhaps converting the struct to an array would work for you?

https://www.mathworks.com/matlabcentral/answers/852330-converting-struct-field-to-array#answer_721080