id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc 7347,duplicate symbol while BOOST_ERROR_CODE_HEADER_ONLY is defined,viboes,Beman Dawes,"Even if BOOST_ERROR_CODE_HEADER_ONLY is not documented I wanted to report this defect. When I define BOOST_ERROR_CODE_HEADER_ONLY building Boost.Thread I get the following error: {{{ ld: duplicate symbol boost::system::system_category() in ../../../bin.v2/libs/thread/build/darwin-4.2.1/debug/threading-multi/future.o and ../../../bin.v2/libs/thread/build/darwin-4.2.1/debug/threading-multi/pthread/thread.o for architecture x86_64 collect2: ld returned 1 exit status ""g++"" -dynamiclib -Wl,-single_module -install_name ""libboost_thread.dylib"" -o ""../../../bin.v2/libs/thread/build/darwin-4.2.1/debug/threading-multi/libboost_thread.dylib"" ""../../../bin.v2/libs/thread/build/darwin-4.2.1/debug/threading-multi/pthread/thread.o"" ""../../../bin.v2/libs/thread/build/darwin-4.2.1/debug/threading-multi/pthread/once.o"" ""../../../bin.v2/libs/thread/build/darwin-4.2.1/debug/threading-multi/future.o"" -headerpad_max_install_names -g }}} I guess that you need to declare the following functions inline. {{{ BOOST_SYSTEM_DECL const error_category & system_category(); BOOST_SYSTEM_DECL const error_category & generic_category(); }}} ",Bugs,closed,To Be Determined,system,Boost 1.51.0,Problem,fixed,,viboes