Is there a way to specialize the std::tr1::hash functor that works the same for the boost implementation and the native MSVC 2008 and GCC 4.3 implementations? It appears that the Boost hash_value free function approach is not supported by the MSVC 2008 implementation, and specialization of the hash functor template has to occur in the original namespace of hash, regardless of any using declarations. Currently I'm using the macro BOOST_HAS_TR1_HASH to decide if I'm using a "native" TR1 implementation or the boost-provided one, and putting it in namespace boost vs. namespace std::tr1 based on the decision. This isn't really a problem, I was just wondering if I had missed an easier way. Thanks, Gregory Peele, Jr. Applied Research Associates Inc.