I'm using RCF (C++ IPC framework) and get the following link error on linux: built_components/librcf.a(RCF.o): In function `__static_initialization_and_destruction_0': /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/system/error_code.hpp:205: undefined reference to `boost::system::get_system_category()' /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/system/error_code.hpp:206: undefined reference to `boost::system::get_generic_category()' /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/system/error_code.hpp:211: undefined reference to `boost::system::get_generic_category()' /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/system/error_code.hpp:212: undefined reference to `boost::system::get_generic_category()' /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/system/error_code.hpp:213: undefined reference to `boost::system::get_system_category()' built_components/librcf.a(RCF.o): In function `boost::asio::error::get_system_category()': /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/asio/error.hpp:218: undefined reference to `boost::system::get_system_category()' built_components/librcf.a(RCF.o): In function `error_code': /home/robi/svn/projects/CacheDaemon/src/ext/boost/boost/system/error_code.hpp:312: undefined reference to `boost::system::get_system_category()' built_components/librcf.a(RCF.o): In function `RCF::FilterAdapter::onWriteCompleted(unsigned long, int)': /home/robi/svn/projects/CacheDaemon/src/ext/rcf/src/RCF/AsioServerTransport.cpp:76: undefined reference to `boost::system::get_system_category()' built_components/librcf.a(RCF.o): In function `RCF::FilterAdapter::onReadCompleted(RCF::ByteBuffer const&, int)': /home/robi/svn/projects/CacheDaemon/src/ext/rcf/src/RCF/AsioServerTransport.cpp:65: undefined reference to `boost::system::get_system_category()' collect2: ld returned 1 exit status make[2]: *** [built_components/CacheClient] Error 1 make[1]: *** [CMakeFiles/CacheClient.dir/all] Error 2 make: *** [all] Error 2 And error_code.cpp from boost.system is included AND linked to... besides the whole thing works fine on Windows... :( Ideas? TIA /Rob