Listing 3: Calling the CComCoClass::Error() method.

HRESULT CUltraMax::LogOn(BSTR sLoginID, BSTR sPassword)
{
    // Vefiry user name and password
    if ( CString(sLoginID) == "UltraMax" && CString(sPassword) == "Music" )
        return S_OK;
    else
    {
        Error("Invalid user name or password");
        return E_FAIL;
    }
}