typedef struct {
    IAccessible IAccessible_iface;
    IOleWindow IOleWindow_iface;
    IEnumVARIANT IEnumVARIANT_iface;

    LONG ref;

    HWND hwnd;
    HWND enum_pos;
    INT role;

    win_class_vtbl vtbl;
} Client;

typedef struct {
    HRESULT (*get_state)(Client *, INT *);
    HRESULT (*get_name)(Client *, BSTR *);
    HRESULT (*get_kbd_shortcut)(Client *, BSTR *);
    HRESULT (*get_value)(Client *, BSTR *);
    HRESULT (*put_value)(Client *, BSTR);
} win_class_vtbl;