Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Tag Type
GV_TAG_TYPEParameter: Exclude
GV_TAG_EXCLUDE_IDParameter: First Tag
GV_TAG_INPUT_STARTParameter: Maximum Tags
GV_TAG_INPUT_COUNTParameter: On
GV_TAG_OPERATOR_ONParameter: Count
GV_TAG_OUTPUT_COUNT