Hi, A program needs boost > 1.58. So, I used boost-1.60 with gcc-4.8. However, as I compile the program, I get many warnings similar to /home/mahmood/boost_1_60_0/boost/mpl/set/aux_/item.hpp(47): warning: "char (&operator||(const boost::mpl::s_item<T, Base> &, boost::mpl::aux::type_wrapper<T> *))[boost::mpl::next<Base::order>::type::value]" declares a non-template function -- add <> to refer to a template instance /home/mahmood/boost_1_60_0/boost/mpl/set/aux_/item.hpp(48): warning: "boost::mpl::aux::no_tag operator%(const boost::mpl::s_item<T, Base> &, boost::mpl::aux::type_wrapper<T> *)" declares a non-template function -- add <> to refer to a template instance Lines are BOOST_MPL_AUX_SET_OVERLOAD( order_tag_, ORDER_BY_KEY, s_item, aux::type_wrapper<T>* ); BOOST_MPL_AUX_SET_OVERLOAD( aux::no_tag, IS_MASKED, s_item, aux::type_wrapper<T>* ); Does that mean I have to change that to aux::type_wrapper< >* ? Regards, Mahmood