Martin Lemieux writes: 1) You describe to much path information in the #include directive in simple_ls.cpp . Like the Boost's .hpp, just start with "boost/(...).hpp". I fixed the path information in the #include directive to be "boost/filesystem/... 2) Then make sure your compiler command line at least mention "-I /user/local/include" or "-I $(INC)" where INC ~includes~ "/user/local/include". I get further, here is the new AIX compiler error: xlc++ -o simple_ls simple_ls.cpp -I /usr/local/include ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::initial_path() ld: 0711-317 ERROR: Undefined symbol: boost::filesystem::native(const std::basic_string&) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::path::path(const char*,bool(*)(const std::basic_string&)) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::system_complete(const boost::filesystem::path&) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::exists(const boost::filesystem::path&) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::path::native_file_string() const ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::is_directory(const boost::filesystem::path&) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::path::native_directory_string() const ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::path::leaf() const ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::detail::dir_itr_init(boost::shared_ptrboost::filesystem::detail::dir_itr_imp&,const boost::filesystem::path&) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::detail::dir_itr_dereference(const boost::shared_ptrboost::filesystem::detail::dir_itr_imp&) ld: 0711-317 ERROR: Undefined symbol: .boost::filesystem::detail::dir_itr_increment(boost::shared_ptrboost::filesystem::detail::dir_itr_imp&) ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information. 2a) On AIX, look inside your makefile. What am I looking for?

[...] MS Visual C++ 6 generates the following similar error when attempting to compile simple_ls.cpp

c:\boost\include\boost-1_32\boost\filesystem\operations.hpp(18) : fatal error C1083: Cannot open include file: 'boost/filesystem/path.hpp': No such file or directory

2b) On MSDEV6, add "c:\boost\include\boost-1_32" in your project settings. More specifically in the "C++" tab, under "Preprocessor" category (drop-down list), and at "Additional include directories:". I did this and I can now build, but I get a linker error: LINK : fatal error LNK1104: cannot open file "libboost_filesystem-vc6-sgd-1_32.lib" Thanks.