Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Matrix Mode
GV_SPLINE_MODEParameter: Use Uniform Distribution
GV_SPLINE_USE_NATURALParameter: Use All Segments
GV_SPLINE_ALL_SEGMENTSParameter: Offset
GV_SPLINE_INPUT_POINTParameter: Segment
GV_SPLINE_INPUT_SEGMENTParameter: Position
GV_SPLINE_OUTPUT_POSITIONParameter: Tangent
GV_SPLINE_OUTPUT_TANGENTParameter: Length
GV_SPLINE_OUTPUT_LENGTHParameter: Closed
GV_SPLINE_OUTPUT_IS_CLOSEDParameter: Segments
GV_SPLINE_OUTPUT_SEGMENTS