title: Identifier not found error when compiling a c++ project with qt and opengl
body: <p>I am trying to compile a C++ program which uses QT and opengl. </p>
  
  <p>When I try to compile it, I am getting this error:</p>
  
  <pre><code> Error  1   error C3861: 'gluErrorString': identifier not found 
  </code></pre>
  
  <p>Looking for this identifier, showed me that it is defined in: line 64 on glu.h file which is part of VS 2012 installation. </p>
  
  <p>Why am I getting this error? </p>
  
  <p>I know that the source code was developed using VS 2010, but I think there should not be any difference, if I use VS 2012.</p>
  
  <p>Should I make any changes to project setup?</p>