title: Can't include <gl/gl.h>
body: <p>I'm using Visual Studio 2010.
  I'm trying to write simple Camera class in OpenGL.
  I need to include gl/gl.h in Camera.h<br>
  gl/gl.h is already included in main.cpp and Camera.h is included in main.cpp
  When I put  </p>
  
  <pre><code>#include &lt;gl/gl.h&gt;
  </code></pre>
  
  <p>in Camera.h i got bunch of errors like this one:<br>
  <code>Error    11    error C2086: 'int APIENTRY' : redefinition    C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\gl\GL.h    1153    1    Gaz 3D</code></p>
  
  <p>files:<br>
  Camera.h</p>
  
  <pre><code>#include &lt;math.h&gt;
  #include &lt;gl/gl.h&gt;
  
  #ifndef _CAMERA_H
  #define _CAMERA_H
  
  class Camera
  {
  private:
      Camera();
  public:
      static Camera&amp; getCamera();
      float x, y, z, rotv, roth;
      void moveForward(float n);
      void moveBackward(float n);
      void moveLeft(float n);
      void moveRight(float n);
      void lookUp(float n);
      void lookDown(float n);
      void lookLeft(float n);
      void lookRight(float n);
  };
  
  #endif
  </code></pre>
  
  <p>main.cpp:</p>
  
  <pre><code>#include &lt;windows.h&gt;
  #include &lt;gl\gl.h&gt;
  #include &lt;gl\glu.h&gt;
  #include &lt;gl\glaux.h&gt;
  #include &lt;math.h&gt;
  #include "Camera.h"
  
  // ... some variables ...
  
  int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,  
                     LPSTR lpCmdLine, int nCmdShow)
  {
      // main code ...
  }
  </code></pre>
  
  <p>What am I doing wrong?</p>