I’m trying to get all of the regression tests to work on my Mac which is running OSX 10.9.2 with Xcode 5.1. "clang++ —version” reports “Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)”. I’m building the boost libraries for c++11. I realize boost 1.55 doesn’t officially support this compiler (yet) so I’m out on the bleeding edge, but it’s almost working. I am cheating a little by manually applying a few of the post-1.55 patches, and if I need to do that to get the regression tests to build that’s fine. When I try to compile function.mem_fun_cxx98 it gives me this error: mem_fun_cxx98.cpp:34:46: error: invalid operands to binary expression ('std::__1::basic_ostream<char>' and 'ostream' (aka 'basic_ostream<char>')) BOOST_TEST(f2(&x, boost::ref(std::cout)) == std::cout); ../../../boost/detail/lightweight_test.hpp:186:28: note: expanded from macro 'BOOST_TEST' #define BOOST_TEST(expr) ((expr)? (void)0: ::boost::detail::test_failed_impl(#expr, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION)) 1 error generated. The error looked to me like a stdlib vs. libc++ kind of thing, so I double-checked the compiler options. For the regression test, bjam is calling the compiler like so: "clang++" -x c++ -std=c++11 -stdlib=libc++ -O3 -O3 -finline-functions -Wno-inline -Wall -DBOOST_ALL_NO_LIB=1 -DNDEBUG -I"../../.." -c -o "/tmp/boost/bin.v2/libs/function/test/mem_fun_cxx98.test/clang-darwin-4.2.1/release/link-static/threading-multi/libs/function/test/mem_fun_cxx98.o” “[SNIP]/mem_fun_cxx98.cpp" The boost libraries are build by calling the compiler: "clang++" -x c++ -std=c++11 -stdlib=libc++ -O3 -O3 -finline-functions -Wno-inline -Wall -DBOOST_ALL_NO_LIB=1 -DBOOST_COROUTINES_SOURCE -DBOOST_SYSTEM_STATIC_LINK=1 -DNDEBUG -I"." -c -o “[SNIP]/bin/boost/bin.v2/libs/coroutine/build/clang-darwin-4.2.1/release/link-static/threading-multi/exceptions.o" "libs/coroutine/src/exceptions.cpp" Whether I bootstrap for toolset clang or darwin doesn’t seem to change anything. Building the library and regression test using clang++ without the c++11 flags works correctly. Is this a known problem that has already been patched for the 1.56 release (I can’t find it if so)? Any suggestions on why this might be happening? Thanks, Chris