c++ - cmake: In which order do I have to specify TARGET_LINK_LIBRARIES -

i struggling again , again linker problems since 1 has specify libraries within target_link_libraries in correct order. how can determine order? example:

i have following libraries

liba depends on boost libb depends on postgresql , liba (and therefore on boost) mytarget uses liba, libb , boost directly (and through libb depends on postgresql) 

since required libaries linked if executable created have specifiy libraries when linking mytarget (the final executable):

target_link_libraries(${applicationname}    libboost_program_options.a  libboost_system.a  libboost_filesystem.a  libboost_date_time.a  libboost_regex.a   # should include boost libraries strangely libs (the ones above) # need specified "by hand"??? ${boost_libraries}   # postgresql stuff libpq.a libsoci_core.a libsoci_postgresql.a libpq.so  # libs libb.a liba.a  ${cmake_thread_libs_init} # pthreads, needed boost ${cmake_dl_libs} # libdl.so etc. )  

since linking boost static cmakelists.txt contains

set(boost_use_static_libs on)  

however, still linking errors such "undefined references boost::re_detail::perl_matcher or boost::date_time::month_formatter"

this annoying, changing lib ordering , undefined references disappear new undefined references appear.

how can identify correct ordering?!

---

edit:

i solved problem above drawing respectively identifying dependencies between libs , ordering them appropriately (therefore libboost_log.a has been added):

target_link_libraries(${applicationname}   libb.a liba.a  # postgresql stuff libpq.a libsoci_core.a libsoci_postgresql.a libpq.so  # boost libboost_program_options.a  libboost_system.a  libboost_log.a  libboost_filesystem.a  libboost_date_time.a  libboost_regex.a  # should include boost libraries strangely libs (the ones above) # need specified "by hand"??? ${boost_libraries}   # lowlevel needed boost ${cmake_thread_libs_init} # pthreads, needed boost ${cmake_dl_libs} # libdl.so etc. )  

so ordering top down. top executable, followed directly used libraries. further dependencies follow , @ end 1 has add low level dependencies (used boost).

in case, when want respect order link libraries, use add_dependencies cmake command. mean:

find_package(boost components date_time filesystem system ...) find_package(postgresql required) if(boost_found , postgresql_found)   include_directories(${boost_include_dirs})   include_directories(${postgresql_include_dirs})    # applicationname -> your_application   # lib_a_target -> liba   # lib_b_target -> libb    set(lib_a_all_deps ${boost_libraries})   set(lib_b_all_deps ${lib_a_all_deps} ${postgresql_libraries})    set(extra_app_deps  ) # here libs aren't in boost or postgre    set(your_app_all_deps ${lib_a_all_deps} ${lib_b_all_deps} ${extra_app_deps})    # here'll add_executable, add_library code    target_link_libraries(${lib_a_target} ${lib_a_all_deps})   add_dependencies(${lib_a_target} ${lib_a_all_deps})    target_link_libraries(${lib_b_target} ${lib_b_all_deps})   add_dependencies(${lib_b_target} ${lib_b_all_deps})    target_link_libraries(${applicationname} ${your_app_all_deps})   add_dependencies(${applicationname} ${your_app_all_deps}) endif() 

i've not tested code i'll more or less. know example part of possible cmakelists.txt need see code writing entirely.

i hope helps you!