The 32-bit CARD_WINDOW_HANDLE data type is used by CardRequestWindow to map a window within system memory. The window can be used to access the PC Card memory or I/O space. CardRequestWindow returns a 32-bit handle to the mapped window with this data type.
typedef PVOID CARD_WINDOW_HANDLE;
You can use the handle for calls to CardMapWindow and CardReleaseWindow.
CardMapWindow, CardReleaseWindow, CardRequestWindow