Hi, I have boost 1.49 installed through homebrew on OSX 10.7. I'm attempting to compile a program making use of boost::program_options. I get the following error: Undefined symbols for architecture x86_64: "boost::program_options::detail::cmdline::get_canonical_option_prefix()", referenced from: boost::program_options::basic_command_line_parser<char>::run() in meanshift_clustering.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) I clearly remember that this used to compile in the past. In the meantime I had uninstalled and re-installed boost a few times. I double-checked the invocation though, the paths are correct: Ld Debug/meanshift_clustering normal x86_64 cd myproject setenv MACOSX_DEPLOYMENT_TARGET 10.7 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.7.sdk -Lmyproject/Debug -Fmyproject/Debug -filelist myproject/myproject.build/Debug/meanshift_clustering.build/Objects-normal/x86_64/meanshift_clustering.LinkFileList -mmacosx-version-min=10.7 -Wl,-search_paths_first -Wl, -headerpad_max_install_names myproject/Debug/libmyproject.dylib /usr/local/lib/libradolan.dylib /usr/local/lib/libnetcdf_c++.dylib /usr/local/lib/libnetcdf.dylib /usr/local/lib/libboost_system-mt.dylib /usr/local/lib/libboost_program_options-mt.dylib /usr/local/lib/libboost_thread-mt.dylib /usr/local/lib/libhdf5.dylib /usr/local/lib/libhdf5_hl.dylib -o myproject/Debug/meanshift_clustering I checked with nm if the symbol is in /usr/local/lib/libboost_program_options-mt.dylib and it is not. This makes me think it's some kind of problem with boost. I do not reference this symbol in my code directly, anywhere. -- View this message in context: http://boost.2283326.n4.nabble.com/Trouble-linking-with-boost-program-option... Sent from the Boost - Users mailing list archive at Nabble.com.