Listing 4: A proper web-service interface.

__interface IUltraMaxService
{
    HRESULT LogOn([in] BSTR LoginID, [in] BSTR Password);
    HRESULT GetSongs([out] LONG* Size,
       [out, retval, size_is(*Size)] SongInfo** Songs);
    HRESULT SetSongs([in] LONG Size, [in, size_is(Size)] SongInfo* Songs);
    HRESULT GetReleaseDate([in, out] BSTR* CurrentDate);
};