title: How to use QtSingleApplication?
body: <ol>
  <li>MacOSX10.8 + Qt5.1 with clang 64bit</li>
  <li>Create Qt Gui application</li>
  <li>in the main.cpp I just add <code>#include &lt;QtSingleApplication&gt;</code></li>
  </ol>
  
  <hr>
  
  <p><strong>Compile error:</strong>    </p>
  
  <pre><code>../untitled/main.cpp:3:10: fatal error: 'QtSingleApplication' file not found
  #include &lt;QtSingleApplication&gt;
           ^
  1 error generated.
  make: *** [main.o] Error 1
  </code></pre>
  
  <hr>
  
  <p>What did I miss?</p>
  
  <hr>
  
  <p>Additional information<br>
  project file has already set <code>QT += widgets</code>    </p>
  
  <p>I google already, it seems need <code>qtlocalpeer.cpp,qtlocalpeer.h,qtsingleapplication.cpp, qtsingleapplication.h,qtsinglecoreapplication.cpp,qtsinglecoreapplication.h</code>, but how to generate these files?    </p>
  
  <p>some posts said it needs include <code>qtsingleapplication.pri</code>, but where is it? I searched my disk I cannot find it.</p>
  
  <hr>
  
  <p><strong>reference</strong><br>
  <a href="http://doc.qt.digia.com/solutions/4/qtsingleapplication/" rel="nofollow">SinleApplication from Qt</a> </p>
  
  <p><a href="http://doc.qt.digia.com/solutions/4/qtsingleapplication/qtsingleapplication.html" rel="nofollow">QtSingleApplication Class Reference</a>    </p>
  
  <p><a href="http://doc.qt.digia.com/solutions/4/qtsingleapplication/qtsingleapplication-example-trivial.html" rel="nofollow">Sample by Qt</a> but where to download source code?</p>