Hi folks, I am trying to use eval_pow() and eval_powm() My code is like this and I am using Visual Studio 12: #include ... boost::multiprecision::cpp_int pow("1234567"); boost::multiprecision::cpp_int base(3); boost::multiprecision::cpp_int result = 0; boost::multiprecision::default_ops::eval_pow(result, base, pow); I cannot figure out what's going on wrong when I compile it, the error message is like the following, Can anyone shed some light please? D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(146): error C2039: 'unsigned_types' : is not a member of 'boost::multiprecision::numberboost::multiprecision::limb_type>,et_on>' 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(191) : see reference to class template instantiation 'boost::multiprecision::detail::canonical_imp>' being compiled 1> with 1> [ 1> Val=unsigned char 1> , Backend=double_type 1> ] 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/integer_ops.hpp(309) : see reference to class template instantiation 'boost::multiprecision::detail::canonical' being compiled 1> KeyGen.cpp(152) : see reference to function template instantiation 'void boost::multiprecision::default_ops::eval_powmboost::multiprecision::cpp_int,int(Backend &,const Backend &,const Backend &,Integer)' being compiled 1> with 1> [ 1> Backend=boost::multiprecision::cpp_int 1> , Integer=int 1> ] 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(146): error C2146: syntax error : missing ',' before identifier 'unsigned_types' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(146): error C2065: 'unsigned_types' : undeclared identifier 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(148): error C2977: 'boost::mpl::find_if' : too many template arguments 1> D:\Develop\C++\boost_1_55_1\boost/mpl/find_if.hpp(33) : see declaration of 'boost::mpl::find_if' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(148): error C2955: 'boost::mpl::find_if' : use of class template requires template argument list 1> D:\Develop\C++\boost_1_55_1\boost/mpl/find_if.hpp(33) : see declaration of 'boost::mpl::find_if' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(136): error C2039: 'signed_types' : is not a member of 'boost::multiprecision::numberboost::multiprecision::limb_type>,et_on>' 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(191) : see reference to class template instantiation 'boost::multiprecision::detail::canonical_imp>' being compiled 1> with 1> [ 1> Val=int 1> , Backend=double_type 1> ] 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/integer_ops.hpp(310) : see reference to class template instantiation 'boost::multiprecision::detail::canonical' being compiled 1> with 1> [ 1> Integer=int 1> ] 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(136): error C2146: syntax error : missing ',' before identifier 'signed_types' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(136): error C2065: 'signed_types' : undeclared identifier 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(138): error C2977: 'boost::mpl::find_if' : too many template arguments 1> D:\Develop\C++\boost_1_55_1\boost/mpl/find_if.hpp(33) : see declaration of 'boost::mpl::find_if' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/number_base.hpp(138): error C2955: 'boost::mpl::find_if' : use of class template requires template argument list 1> D:\Develop\C++\boost_1_55_1\boost/mpl/find_if.hpp(33) : see declaration of 'boost::mpl::find_if' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/integer_ops.hpp(336): error C2780: 'enable_if>,void>::type boost::multiprecision::backends::eval_right_shift(boost::multiprecision::backends::cpp_int_backend &,T)' : expects 2 arguments - 1 provided 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/cpp_int/bitwise.hpp(355) : see declaration of 'boost::multiprecision::backends::eval_right_shift' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/integer_ops.hpp(336): error C2780: 'enable_if_c>::value,void>::type boost::multiprecision::backends::eval_right_shift(boost::multiprecision::backends::cpp_int_backend &,boost::multiprecision::double_limb_type)' : expects 2 arguments - 1 provided 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/cpp_int/bitwise.hpp(298) : see declaration of 'boost::multiprecision::backends::eval_right_shift' 1>D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/integer_ops.hpp(336): error C2780: 'void boost::multiprecision::default_ops::eval_right_shift(T &,const T &,const V)' : expects 3 arguments - 1 provided 1> D:\Develop\C++\boost_1_55_1\boost/multiprecision/detail/default_ops.hpp(758) : see declaration of 'boost::multiprecision::default_ops::eval_right_shift' ------------------------------ Thanks, -Anderson Lebowski