title: I have a Huge XML File of which I want to read its childtrees into the C++ boost::property_tree::pTree type
body: <p>The normal way of doing it is using</p>
  <pre><code>boost::property_tree::ptree pt1;
  boost::property_tree::read_xml( XML_FILE_PATH, pt1  );
  </code></pre>
  <p>But what this does is that it reads the entire XML File, which is really huge in the pt1</p>
  <p>So I think it is inefficient when we just want to read a childTree.</p>
  <p>There is another overload function for read_xml which takes in the File Type istream but I don't know how to work with to solve this</p>
  <pre><code>boost::property_tree::read_xml( iStream, pt1  );
  </code></pre>
  <p>Thanks</p>