title: what does /= do in the c++ example below?
body: <p>Example:</p>
  
  <pre><code>boost::filesystem::path filename;
  filename /= boost::filesystem::temp_directory_path();
  filename /= boost::filesystem::unique_path();
  </code></pre>
  
  <p>Is it better than?</p>
  
  <p><code>auto filename = boost::filesystem::unique_path("%%%%-%%%%-%%%%-%%%%");</code></p>