I suppose, it's a begginer's linux problem but I didn't found the answer neither in the documentation nor in the internet forums... After installing boost on my system (see how at the end of this email), I wanted to compile simple_ls.cpp, the filesystem example. everything works when creating the .o but when linking a lot of undefined references arised. What have I done wrong? g++ -c simple_ls.cpp [marc@localhost ls]$ g++ -c simple_ls.cpp [marc@localhost ls]$ ls ls/ simple_ls.cpp* simple_ls.o [marc@localhost ls]$ g++ simple simple_ls.cpp simple_ls.o [marc@localhost ls]$ g++ simple_ls.cpp -o simple_ls /tmp/ccjMYBxo.o(.text+0x19): In function `main': : undefined reference to `boost::filesystem::initial_path()' /tmp/ccjMYBxo.o(.text+0x44): In function `main': : undefined reference to `boost::filesystem::native(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' /tmp/ccjMYBxo.o(.text+0x55): In function `main': : undefined reference to `boost::filesystem::path::path[in-charge](char const*, bool (*)(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&))' /tmp/ccjMYBxo.o(.text+0x64): In function `main': : undefined reference to `boost::filesystem::system_complete(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x119): In function `main': : undefined reference to `boost::filesystem::exists(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x13c): In function `main': : undefined reference to `boost::filesystem::path::native_file_string() const' /tmp/ccjMYBxo.o(.text+0x1bf): In function `main': : undefined reference to `boost::filesystem::is_directory(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x1e2): In function `main': : undefined reference to `boost::filesystem::path::native_directory_string() const' /tmp/ccjMYBxo.o(.text+0x291): In function `main': : undefined reference to `boost::filesystem::is_directory(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x2ca): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccjMYBxo.o(.text+0x351): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccjMYBxo.o(.text+0x418): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccjMYBxo.o(.text+0x586): In function `main': : undefined reference to `boost::filesystem::path::native_file_string() const' /tmp/ccjMYBxo.o(.gnu.linkonce.t._ZN5boost10filesystem18directory_iteratorC1ERKNS0_4pathE+0x2d): In function `boost::filesystem::directory_iterator::directory_iterator[in-charge](boost::filesystem::path const&)': : undefined reference to `boost::filesystem::detail::dir_itr_init(boost::shared_ptr<boost::filesystem::detail::dir_itr_imp>&, boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.gnu.linkonce.t._ZNK5boost10filesystem18directory_iterator11dereferenceEv+0xd): In function `boost::filesystem::directory_iterator::dereference() const': : undefined reference to `boost::filesystem::detail::dir_itr_dereference(boost::shared_ptr<boost::filesystem::detail::dir_itr_imp> const&)' /tmp/ccjMYBxo.o(.gnu.linkonce.t._ZN5boost10filesystem18directory_iterator9incrementEv+0xd): In function `boost::filesystem::directory_iterator::increment()': : undefined reference to `boost::filesystem::detail::dir_itr_increment(boost::shared_ptr<boost::filesystem::detail::dir_itr_imp>&)' collect2: ld returned 1 exit status thank you in advance again. PS: my system is: [marc@localhost html]$ g++ -v Reading specs from /usr/lib/gcc-lib/i586-mandrake-linux-gnu/3.3.2/specs Configured with: ../configure --prefix=/usr --libdir=/usr/lib --with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --enable-long-long --enable-__cxa_atexit --enable-clocale=gnu --enable-languages=c,c++,ada,f77,objc,java,pascal --host=i586-mandrake-linux-gnu --with-system-zlib Thread model: posix gcc version 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk) And i've installed boost using these packages: Nombre: libboost1 Versión: 1.31.0-5mdk /usr/lib/libboost_date_time.so.1 /usr/lib/libboost_date_time.so.1.31.0 /usr/lib/libboost_filesystem.so.1 /usr/lib/libboost_filesystem.so.1.31.0 /usr/lib/libboost_prg_exec_monitor.so.1 /usr/lib/libboost_prg_exec_monitor.so.1.31.0 /usr/lib/libboost_python.so.1 /usr/lib/libboost_python.so.1.31.0 /usr/lib/libboost_regex.so.1 /usr/lib/libboost_regex.so.1.31.0 /usr/lib/libboost_signals.so.1 /usr/lib/libboost_signals.so.1.31.0 /usr/lib/libboost_test_exec_monitor.so.1 /usr/lib/libboost_test_exec_monitor.so.1.31.0 /usr/lib/libboost_thread.so.1 /usr/lib/libboost_thread.so.1.31.0 /usr/lib/libboost_unit_test_framework.so.1 /usr/lib/libboost_unit_test_framework.so.1.31.0 /usr/share/doc/libboost1-1.31.0 /usr/share/doc/libboost1-1.31.0/LICENSE_1_0.txt Nombre: libboost1-devel Versión: 1.31.0-5mdk Archivos: /usr/include/boost /usr/include/boost/aligned_storage.hpp /usr/include/boost/any.hpp /usr/include/boost/array.hpp /usr/include/boost/assert.hpp /usr/include/boost/bind /usr/include/boost/bind.hpp /usr/include/boost/bind/apply.hpp /usr/include/boost/bind/arg.hpp /usr/include/boost/bind/bind_cc.hpp /usr/include/boost/bind/bind_mf_cc.hpp /usr/include/boost/bind/bind_template.hpp /usr/include/boost/bind/make_adaptable.hpp /usr/include/boost/bind/mem_fn_cc.hpp /usr/include/boost/bind/mem_fn_template.hpp /usr/include/boost/bind/mem_fn_vw.hpp /usr/include/boost/bind/placeholders.hpp /usr/include/boost/bind/protect.hpp /usr/include/boost/blank.hpp /usr/include/boost/blank_fwd.hpp /usr/include/boost/call_traits.hpp ... /usr/lib/libboost_date_time.so /usr/lib/libboost_filesystem.so /usr/lib/libboost_prg_exec_monitor.so /usr/lib/libboost_python.so /usr/lib/libboost_regex.so /usr/lib/libboost_signals.so /usr/lib/libboost_test_exec_monitor.so /usr/lib/libboost_thread.so /usr/lib/libboost_unit_test_framework.so /usr/share/doc/libboost1-devel-1.31.0 /usr/share/doc/libboost1-devel-1.31.0/README /usr/share/doc/libboost1-devel-1.31.0/boost.css /usr/share/doc/libboost1-devel-1.31.0/c++boost.gif Nombre: libboost1-static-devel Versión: 1.31.0-5mdk /usr/lib/libboost_date_time.a /usr/lib/libboost_filesystem.a /usr/lib/libboost_prg_exec_monitor.a /usr/lib/libboost_python.a /usr/lib/libboost_regex.a /usr/lib/libboost_signals.a /usr/lib/libboost_test_exec_monitor.a /usr/lib/libboost_unit_test_framework.a