Someone on stackoverflow is having a problem with BOOST_STRONG_TYPEDEF getting defined twice. There's a good recommendation there about boost/strong_typedef.hpp merely including boost/serialization/strong_typedef.hpp. Regardless, it's strange that trunk and release have been out of sync in this regard for so long. Robert? http://stackoverflow.com/questions/16901250/why-does-boost-include-two-diffe... -- Eric Niebler Boost.org http://www.boost.org