Access control rules are all checked at compile time. There's literally nothing to store. If you want proof, check the output of your compiler. The only thing a

Access control rules are all checked at compile time. There's literally nothing to store. If you want proof, check the output of your compiler. The only thing a non-virtual struct/class might do is reorder member variables if they're of different access controls, but if you're just using a C-style struct but with private member variables and public non-virtual member functions, it has literally the same memory layout as it would in C.