Hello, I want to add support for libc++, the c++ standard library attached to clang, to boost. Fixes required should not be attached to clang, as clang can use various standard libraries. Is there a standard way I should add the library, or just add the macro where needed. The best macro to use for detecting libc++ is _LIBCPP_VERSION. Hopefully the changes required will be minimal. One place where libc++ needs to be mentioned in is detail/container_fwd.hpp, as forward declarations simply don't work. Can I just attach _LIBCPP_VERSION to: #if defined(BOOST_DETAIL_NO_CONTAINER_FWD) \ || ((defined(__GLIBCPP__) || defined(__GLIBCXX__)) \ && (defined(_GLIBCXX_DEBUG) || defined(_GLIBCXX_PARALLEL))) \ || BOOST_WORKAROUND(__BORLANDC__, > 0x551) \ || BOOST_WORKAROUND(__DMC__, BOOST_TESTED_AT(0x842)) \ || (defined(__SGI_STL_PORT) || defined(_STLPORT_VERSION)) Or is there a better / more offical way libc++ should be worked in? Chris