title: Attempting to use Boost.Filesystem however it doesn't seem to link?
body: <p>I'm using OS X 10.7.3. I've been playing with the boost headers for a while now and i wanted to move onto using the Boost.Filesystem lib however it keeps throwing this message at me:</p>
  
  <pre><code>Undefined symbols for architecture x86_64:
    "boost::system::generic_category()", referenced from:
        __static_initialization_and_destruction_0(int, int)in ccOhIhNG.o
        boost::filesystem3::detail::create_directories(boost::filesystem3::path const&amp;,     boost::system::error_code*)in libboost_filesystem.a(operations.o)
        boost::filesystem3::detail::canonical(boost::filesystem3::path const&amp;,     boost::filesystem3::path const&amp;, boost::system::error_code*)in     libboost_filesystem.a(operations.o)
    "boost::system::system_category()", referenced from:
        __static_initialization_and_destruction_0(int, int)in ccOhIhNG.o
        (anonymous namespace)::error(bool, boost::system::error_code const&amp;,     boost::filesystem3::path const&amp;, boost::system::error_code*, std::basic_string&lt;char,     std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt; const&amp;)in libboost_filesystem.a(operations.o)
        (anonymous namespace)::error(bool, boost::filesystem3::path const&amp;,     boost::system::error_code*, std::basic_string&lt;char, std::char_traits&lt;char&gt;,     std::allocator&lt;char&gt; &gt; const&amp;)in libboost_filesystem.a(operations.o)
        (anonymous namespace)::error(bool, boost::filesystem3::path const&amp;,     boost::filesystem3::path const&amp;, boost::system::error_code*, std::basic_string&lt;char,     std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt; const&amp;)in libboost_filesystem.a(operations.o)
        boost::filesystem3::detail::dir_itr_close(void*&amp;, void*&amp;)in     libboost_filesystem.a(operations.o)
        boost::filesystem3::detail::directory_iterator_increment(boost::filesystem3::directory_itera    tor&amp;, boost::system::error_code*)in libboost_filesystem.a(operations.o)
        boost::filesystem3::detail::directory_iterator_construct(boost::filesystem3::directory_itera    tor&amp;, boost::filesystem3::path const&amp;, boost::system::error_code*)in     libboost_filesystem.a(operations.o)
        ...
  ld: symbol(s) not found for architecture x86_64
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>i get this when i try to compile using this:</p>
  
  <pre><code>g++ -o test main.cpp -I -l/opt/local/include ~/boost/libs/libboost_filesystem.a
  </code></pre>
  
  <p>So i went back to the boost.org tutorials and tried out the regex example. It worked perfectly using this: </p>
  
  <pre><code>g++ -o test main.cpp -I -l/opt/local/include ~/boost/libs/libboost_regex.a
  </code></pre>