title: undefined reference to `gluOrtho2D'
body: <p><a href="http://programanddesign.com/cpp/qt-opengl-code-example/" rel="nofollow">http://programanddesign.com/cpp/qt-opengl-code-example/</a></p>
  
  <p>I am trying out above example and included </p>
  
  <pre><code>#include &lt;GL/glu.h&gt;
  #include &lt;GL/glut.h&gt;
  </code></pre>
  
  <p>as well. but I am getting a gluOrtho2D undefined error.  what am I doing wrong here ?</p>