I'm not even sure if this is possible anymore. I was working on migrating some matlab models/autogenerated code from 2009->2019a.
It looks like they used to generate a parameters structure with format <modelName>_sl_P that would get passed in as an input to the initialize/step functions. In 2019a, I'm able to generate parameter's into the <modelName>_sl_P structure inside of the <modelName>_sl_data.cpp file.
I'm just wondering if there is anyway to force parameters to be fed in as an input to the step function rather than being accessed globally via includes?