0, _
                                    Optional hIcon As Long = 0, _
                                    Optional hIconSm As Long = 0, _
                                    Optional cbClassExtra As Long = 0, _
                                    Optional cbWndExtra As Long = 0) As Boolean
  Dim wc As tWNDCLASSEX

  Debug.Assert (m_sClass = vbNullString)                  'This method should
   only be called once or never for a predefined class
  
  m_sClass = sClass                                       '