The current Boost.Config check for BOOST_NO_EXTERN_TEMPLATE uses incorrect syntax. The test, in libs/config/test/boost_no_extern_template.ipp, looks like this: namespace boost_no_extern_template { extern template<class T> void f(T); int test() { return 0; } } The "extern" in C++0x extern templates can only be placed on explicit template instantiations. Here's a better test: namespace boost_no_extern_template { template<typename T, typename U> void f(T* p1, U* p2) { p1 = p2; } extern template void f(int*, float*); int test() { return 0; } } If the compiler rejects or ignores the "extern" in that explicit template instantiation declaration, we'll get an (invalid) compiler error. Grepping through the compiler configurations, BOOST_NO_EXTERN_TEMPLATE is set for several compilers that do in fact have support for C++0x extern templates, namely GCC and EDG-based compilers (when in either in C++0x or non-strict mode). - Doug