I had to apply the attached patch to use Boost.Filesystem CVS HEAD with MinGW (GCC 3.4.5). Index: boost/filesystem/convenience.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/filesystem/convenience.hpp,v retrieving revision 1.12 diff -u -p -r1.12 convenience.hpp --- boost/filesystem/convenience.hpp 9 Mar 2006 22:14:08 -0000 1.12 +++ boost/filesystem/convenience.hpp 17 Jun 2006 14:54:11 -0000 @@ -28,7 +28,7 @@ # else # 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