Proper Usage of the MFC Framework

[GCDEF]

I guess returning is not the right word. The function call should take in a double pointer (pointing to a structure containing breps and other nurbs data necessary for the C application to perform calculations). In the end, the structure is created and the struct is allocated to that pointer.

So if I am not meant to call the InitInstance(), the only way to bring up my MFC application is through createProcess() or ShellExecute()? What if I remake my application as a DLL?

Then you call functions directly as you would with any DLL. It sounds more like that's what you want.