I'm testing the RC 1.34 branch and I believe there should be an inline statement in one of the macros at the top of the convenience.hpp header. from line 29 # define BOOST_FS_FUNC(BOOST_FS_TYPE) inline BOOST_FS_TYPE typedef boost::filesystem::path Path; -# define BOOST_FS_FUNC_STRING std::string +# define BOOST_FS_FUNC_STRING inline std::string # define BOOST_FS_TYPENAME # endif Otherwise the functions extension and basename will get multiple definitions errors while linking. thanks, -- Arvid Norberg