You can also with certain type of APIs increase the size of structs and still be ABI compatible. This is usually done by encoding the size of the type as a memb

You can also with certain type of APIs increase the size of structs and still be ABI compatible. This is usually done by encoding the size of the type as a member of the struct that is usually assigned via `x.size = sizeof(x)` and passed around as pointers. Takes real care to maintain that though. IIRC this appears somewhat frequently in Win32.