xpressocore/description/gvrandom.hParameters are accessed with cinema::C4DAtom::GetParameter() and cinema::C4DAtom::SetParameter(). See Parameters.
Parameter: Random Mode
GV_RANDOM_MODEGV_RANDOM_MODE_FREEGV_RANDOM_MODE_TIMEParameter: Positive Only
GV_RANDOM_POSITIVEParameter: Random Seed
GV_RANDOM_SEEDParameter: Bool
GV_RANDOM_OUTPUT_BOOLParameter: Integer
GV_RANDOM_OUTPUT_INTEGERParameter: Real
GV_RANDOM_OUTPUT_REALParameter: Vector
GV_RANDOM_OUTPUT_VECTOR