This issue can be triggered in a few different ways. First, certain settings in the model's Configuration Parameters can cause the issue. In Configuration Parameters, under the Code Generation/Interfaces tab, make sure the "Code interface packaging" parameter is set to "Nonreusable.".
If that is not the issue, then check the documentation for the various blocks in your model. On the block's documentation page, under "Extended Capabilities" and "C/C++ Code Generation," ensure the blocks in your model aren't marked as "Not recommended for production code." . The "Step" block in particular is known to cause this issue. If blocks in your model are the issue, consider using alternative methods to achieve your desired functionality so that the offending blocks can be eliminated.
