Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Inputs First
GV_GROUP_INPUTS_FIRSTParameter: Active
GV_GROUP_ACTIVEParameter: Protect...
GV_GROUP_LOCKParameter: Unprotect...
GV_GROUP_UNLOCKParameter: Enable
GV_GROUP_ENABLED