I am using boost_1_61_0. In my code I have: #include <boost/regex.hpp> static boost::regex testxp("["); I have these libraries: libboost_regex.a libboost_regex.so I can see these libraries have symbols: LIBRARY: Shared object libboost_regex.so: 136 symbols imported. LIBRARY: Shared object libboost_system.so: 7 symbols imported. To build my program I have added these linking options: -Wl,-bnoquiet -Wl,-Bstatic -lboost_regex -lboost_system -Wl,-Bdynamic But I get this error during linking: ld: 0711-317 ERROR: Undefined symbol: .boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign(char const*, char const*, unsigned int) But that symbol is there: machine:/home> nm libboost_regex.so nm libboost_regex.so |grep do_assign ._ZN5boost11basic_regexIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9do_assignEPKcS7_j T 268508592 machine:/home> c++filt ._ZN5boost11basic_regexIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9do_assignEPKcS7_j .boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign(char const*, char const*, unsigned int)