title: Boost linker error: Unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::get_system_category(void)"
body: <p>I'm just getting started with Boost for the first time, details:</p>
  
  <ol>
  <li>I'm using Visual Studio 2008 SP1</li>
  <li>I'm doing an x64 Build</li>
  <li>I'm using boost::asio only (and any dependencies it has)</li>
  </ol>
  
  <p>My code now compiles, and I pointed my project at the boost libraries (after having built x64 libs) and got past simple issues, now I am facing a linker error:</p>
  
  <pre><code>2&gt;BaseWebServer.obj : error LNK2001: unresolved external symbol "class boost::system::error_category const &amp; __cdecl boost::system::get_system_category(void)" (?get_system_category@system@boost@@YAAEBVerror_category@12@XZ)
  2&gt;BaseWebServer.obj : error LNK2001: unresolved external symbol "class boost::system::error_category const &amp; __cdecl boost::system::get_generic_category(void)" (?get_generic_category@system@boost@@YAAEBVerror_category@12@XZ)
  </code></pre>
  
  <p>any ideas?</p>
  
  <hr>
  
  <p>I added this define: #define BOOST_LIB_DIAGNOSTIC</p>
  
  <p>And now in my output I see this:</p>
  
  <pre><code>1&gt;Linking to lib file: libboost_system-vc90-mt-1_38.lib
  1&gt;Linking to lib file: libboost_date_time-vc90-mt-1_38.lib
  1&gt;Linking to lib file: libboost_regex-vc90-mt-1_38.lib
  </code></pre>
  
  <p>which seems to indicate it is infact linking in the system lib.</p>