hi, I am using BOOST_STATIC_CONST for static class members of a base class. I have following situation: template <int T> class A { typedef typename MyType<T>::value_type value_type; BOOST_STATIC_CONST(typename value_type::some_type, MY_CONSTANT = 0); }; template <int T> class B : public A<T> { typedef A<T> Base; typedef typename Base::value_type value_type; BOOST_STATIC_CONST(typename value_type::some_type, MY_CONSTANT = Base::MY_CONSTANT); }; or template <int T> class B : public A<T> { typedef A<T> Base; typedef typename Base::value_type value_type; using Base::MY_CONSTANT; }; for both cases I got a linker error: /usr/bin/ld: Undefined symbols: B<0>::MY_CONSTANT what am I doing wrong? I am using darwin gcc4.0.1 and Boost from CVS thanks a lot! michael