The execution of the generated code is governed by the code generated in ert_main.c. By default, the main() consists of an empty while loop - the reason is to force users to configure the execution according to their application.
However, if all you'd like to do is run your simulation and log the data in the form of a MAT-file, select "MAT-file Logging" on from the Real-Time Workshop > Interface pane of your model's Configuration Parameters window. When you generate code this time, the model step function is called and any logged outputs/states are saved to a MAT-file.
Alternatively, you can add your own code to the main() function before building it, in order to visualize it using your own C libraries.
