Cannot link Boost regex

Question

I am currently trying to compile a Contraction Hierachies implementation by KIT which requires Boost::Regex. The supplied Makefile already makes sure (and I have also double-checked this manually) that g++ is supplied with the -lboost_regex switch. If the library is not installed, g++ will complain.

So I installed the library from my package sources and tried compiling again. This time I am getting a huge load of linker errors regarding Boost::Regex. Here is a short excerpt:

main.o: In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::unwind_extra_block(bool)':
main.cpp:(.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE18unwind_extra_blockEb[_ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE18unwind_extra_blockEb]+0x2c): undefined reference to `boost::re_detail::put_mem_block(void*)'
main.o: In function `void boost::re_detail::raise_error<boost::regex_traits_wrapper<boost::regex_traits<char, boost::cpp_regex_traits<char> > > >(boost::regex_traits_wrapper<boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::error_type)':
main.cpp:(.text._ZN5boost9re_detail11raise_errorINS_20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE[_ZN5boost9re_detail11raise_errorINS_20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE]+0x7d): undefined reference to `boost::re_detail::get_default_error_string(boost::regex_constants::error_type)'
main.cpp:(.text._ZN5boost9re_detail11raise_errorINS_20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE[_ZN5boost9re_detail11raise_errorINS_20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE]+0xb1): undefined reference to `boost::re_detail::raise_runtime_error(std::runtime_error const&)'
main.cpp:(.text._ZN5boost9re_detail11raise_errorINS_20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE[_ZN5boost9re_detail11raise_errorINS_20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE]+0xcb): undefined reference to `boost::re_detail::get_default_error_string(boost::regex_constants::error_type)'
main.o: In function `__gnu_cxx::__normal_iterator<char const*, std::string> boost::re_detail::re_is_set_member<__gnu_cxx::__normal_iterator<char const*, std::string>, char, boost::regex_traits<char, boost::cpp_regex_traits<char> >, unsigned int>(__gnu_cxx::__normal_iterator<char const*, std::string>, __gnu_cxx::__normal_iterator<char const*, std::string>, boost::re_detail::re_set_long<unsigned int> const*, boost::re_detail::regex_data<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, bool)':
main.cpp:(.text._ZN5boost9re_detail16re_is_set_memberIN9__gnu_cxx17__normal_iteratorIPKcSsEEcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEjEET_SB_SB_PKNS0_11re_set_longIT2_EERKNS0_10regex_dataIT0_T1_EEb[_ZN5boost9re_detail16re_is_set_memberIN9__gnu_cxx17__normal_iteratorIPKcSsEEcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEjEET_SB_SB_PKNS0_11re_set_longIT2_EERKNS0_10regex_dataIT0_T1_EEb]+0x17b): undefined reference to `boost::re_detail::cpp_regex_traits_implementation<char>::transform_primary(char const*, char const*) const'
main.cpp:(.text._ZN5boost9re_detail16re_is_set_memberIN9__gnu_cxx17__normal_iteratorIPKcSsEEcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEjEET_SB_SB_PKNS0_11re_set_longIT2_EERKNS0_10regex_dataIT0_T1_EEb[_ZN5boost9re_detail16re_is_set_memberIN9__gnu_cxx17__normal_iteratorIPKcSsEEcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEjEET_SB_SB_PKNS0_11re_set_longIT2_EERKNS0_10regex_dataIT0_T1_EEb]+0x4c0): undefined reference to `boost::re_detail::cpp_regex_traits_implementation<char>::transform(char const*, char const*) const'
main.o: In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::extend_stack()':
main.cpp:(.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE12extend_stackEv[_ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE12extend_stackEv]+0x18): undefined reference to `boost::re_detail::get_mem_block()'
main.o: In function `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::string>, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::string> > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::match_imp()':
main.cpp:(.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv[_ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv]+0xc): undefined reference to `boost::re_detail::get_mem_block()'
main.cpp:(.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv[_ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv]+0x19e): undefined reference to `boost::re_detail::verify_options(unsigned int, boost::regex_constants::_match_flags)'
main.cpp:(.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv[_ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv]+0x254): undefined reference to `boost::re_detail::put_mem_block(void*)'
main.cpp:(.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv[_ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9match_impEv]+0x3c6): undefined reference to `boost::re_detail::put_mem_block(void*)'

This looks very much like the compiler did not find the library at all. In fact, when I don't supply the -lboost_regex switch the output remains the same (I ran a hash on it).

However, running the linker with the -Wl,--verbose switch as suggested in nuwen MinGW + Boost- error linking boost_regex shows that the library is found:

attempt to open /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libboost_regex.so succeeded
-lboost_regex (/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../lib/libboost_regex.so)

All I know is that this is likely a different boost version than what was around when the software was written (I don't know which. I am using 1.53 now.) but from looking at the code it seems it should still work. Also I am using the headers from this boost version so the compiler should already complain if function signatures have changed.

How can I get this to link? Am I missing something?

Answer 1

Linker switches are in the wrong order. make tries to do this:

g++ -lboost_regex -lboost_iostreams -o main main.o

This is what actually works (at least with gcc 4.8.1):

g++ -o main main.o -lboost_regex -lboost_iostreams

So to fix the compilation error you should substitue line 6 in the Makefile with the following:

    $(CXX) -o $@ $^ $(LIBS) $(LINK)

Answer 2

Boost regex (and other boost libs, probably) may also fail to link if you have multiple versions of boost available, and the linker path and include paths point to different versions (this happened to me with cmake when using find_package(Boost ...) where a path was specified while also having a different version installed in the system root.

The solution in the case of cmake was to add include_directories(${Boost_INCLUDE_DIRS}) to CMakeLists.txt as well as ensuring the correct link ordering in the target_link_libraries.