MASK             Return a bit mask                                   Operator

  MASK record_name                  Returns a mask where the bits reserved
                                    to represent bit fields in the record
                                    definition are 1, the rest are 0

  MASK record_field_name            Returns a mask where the bits reserved
                                    for the field in the record definition
                                    are 1, the rest are 0

  MASK enum_name                    Returns a mask where the bits required
                                    to represent up to the maximum value
                                    present in the enum definition are 1,
                                    the rest are 0