Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Tag Type
GV_TAG_TYPE
Parameter: Exclude
GV_TAG_EXCLUDE_ID
Parameter: First Tag
GV_TAG_INPUT_START
Parameter: Maximum Tags
GV_TAG_INPUT_COUNT
Parameter: On
GV_TAG_OPERATOR_ON
Parameter: Count
GV_TAG_OUTPUT_COUNT