title: I can't include boost header files in my own header
body: <p>util.h</p>
  
  <pre><code>#include &lt;boost/property_tree/ptree.hpp&gt;
  
  namespace core {
      class Config {
          boost::property_tree::ptree pt;
  ....
  </code></pre>
  
  <p>I get the error:</p>
  
  <blockquote>
    <p>Error 2   error C1083: Cannot open include file:
    'boost/property_tree/ptree.hpp': No such file or
    directory d:\path\kserver\lib\util.h  1   1   kserver</p>
  </blockquote>
  
  <p>The full list of options for compiling is:</p>
  
  <pre><code>/GS /TP /W3 /Zc:wchar_t /I"D:\Development\Tools\boost_1_57_0" /Zi /Gm- /Od /Ob0 /Fd"core.dir\Debug\vc120.pdb" /fp:precise /D "WIN32" /D "_WINDOWS" /D "_DEBUG" /D "BOOST_ALL_NO_LIB" /D "CMAKE_INTDIR=\"Debug\"" /D "_MBCS" /errorReport:prompt /WX- /Zc:forScope /RTC1 /GR /Gd /MDd /Fa"Debug/" /EHsc /nologo /Fo"core.dir\Debug\" /Fp"core.dir\Debug\core.pch" 
  </code></pre>
  
  <p>If I include <code>ptree.hpp</code> in the cpp file it works fine.</p>
  
  <p>How can I define a variable in my header file? Please note that the question is not specific to <code>ptree</code>.</p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>I figured out what it is. My solution is several projects where one is a library used by the main project. The lib header includes the <code>boost</code> header file. When including the header file in my main project the hpp can not be found... this means that to build the main project I have to do one of two things:</p>
  
  <ol>
  <li>Include the boost headers to the main project too</li>
  <li>Remove the header includes and not expose a boost variable to the main project</li>
  </ol>
  
  <p>Is there another option so I can still keep the include in the header file?</p>