Function ShellMessageBoxA 

pub unsafe fn ShellMessageBoxA<P2, P3>(
    happinst: Option<HINSTANCE>,
    hwnd: Option<HWND>,
    lpctext: P2,
    lpctitle: P3,
    fustyle: MESSAGEBOX_STYLE,
) -> i32
where
    P2: Param<PCSTR>,
    P3: Param<PCSTR>,