IDirect3D9Ex::CreateDeviceEx

DX9 vtable[20] → HRESULT

IDirect3D9Ex::CreateDeviceEx is a method of the COM interface IDirect3D9Ex in Direct3D 9. Its function pointer sits at vtable index 20 — the zero-based slot in that interface's virtual method table, counted from QueryInterface and including every entry inherited from a base interface. It takes 7 parameters (adapter_idx, device_type, focus_window, flags, parameters, mode, device) and returns HRESULT.

COM methods are reached through that table rather than by an exported name, so the slot index is what a wrapper, an interface hook or a disassembly listing has to resolve against. The parameter order and types below are the ones this interface declares.