Hi, we call it like that : DonneesCP dcp = InterfaceDonneesCP_OC::instance()->getDonneesCP(); The method "instance" returns a InterfaceDonneesCP_OC* (non const) But why should this prevent from calling a const method ? Additionnal informations : InterfaceDonneesCP_OC inherits (public) InterfaceDonneesCP where the two getDonneesCP are defined. François