IDirectDrawSurface::Lock

DDraw vtable[25] → HRESULT

IDirectDrawSurface::Lock is a method of the COM interface IDirectDrawSurface in DirectDraw. Its function pointer sits at vtable index 25 — 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 4 parameters (rect, surface_desc, flags, event) 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.