C++ Extern Class Declaration
<p>Edit: Ok I wrote a little test program to show here. Here is the Source Code.</p>

<p>main.cpp:</p>

<pre><code>#include "core.h"

Core core;

int main()
{
  core.coreFunction();
}
</code></pre>

<p>core.h:</p>

<pre><code>#ifndef CORE_H__
#define CORE_H__

#include "definitions.h"
#include "window.h"

class Core
{
public:
  Window window;
  void coreFunction()
  {
    window.windowFunction();
  }
};
extern Core core;

#endif
</code></pre>

<p>definitions.h</p>

<pre><code>#ifndef DEFINITIONS_H__
#define DEFINITIONS_H__

class Core;
class Window;

#endif
</code></pre>

<p>window.h</p>

<pre><code>#ifndef WINDOW_H__
#define WINDOW_H__

class Window
{
public:

   void windowFunction()
   {
     core.coreFunction();
   }
};

#endif
</code></pre>

<p>With this Test Program I get the following Error: <strong>window.h(10): error C2065: 'core' : undeclared identifier</strong>. I hope this clarifies my problem a little bit. Please ignore that these functions make no sense its just for showing what i did because my original code is way to long to post here.</p>
