C / C++ / MFC

<br />
// Unique ID class<br />
class __declspec(dllexport/dllimport) CxID {<br />
public:<br />
  // C-tor, D-tor, some other methods.<br />
  static const int GetID();<br />
private:<br />
  static int iID;<br />
};<br />
// Interfaces<br />
class IxA {<br />
  virtual int GetA() = 0;<br />
};<br />
class IxB_Only {<br />
  virtual int GetB() = 0;<br />
};<br />
class IxB: public IxA, public IxB_Only {<br />
};<br />
<br />
extern __declspec(dllexport/dllimport) IxB *GetObject(); // Just a test function<br />

<br />
#include "API.h"<br />
class CxA: public CxID, public IxA {<br />
public:<br />
  // C-tor, D-tor, some methods.<br />
  int GetA() { return 0xAA; }<br />
private:<br />
  ID m_ID;<br />
};<br />
class CxB: public CxA, public IxB_Only {<br />
  // C-tor, D-tor, some methods.<br />
  int GetB() { return 0xBB; }<br />
};<br />

<br />
CxB *g_pObj;<br />
BOOL APIENTRY DllMain(...) {<br />
   ...<br />
   case DLL_PROCESS_ATTACH:<br />
     g_pObj = new CxB();<br />
   break;<br />
   ...<br />
}<br />
<br />
// Just a global function to return pointer on global object created in DLL<br />
__declspec(dllexport/dllimport) IxB *GetObject() {<br />
  return (IxB*)g_pObj;<br />
};<br />

<br />
IxB *pObj = GetObj();<br />

pObj
  |--[CxB]
  |    |--CxA
  |    |   |--IxA __vfptr with good address and fuctions
  |    |--IxB_Only __vfptr with good address and functions
  |--IxA __vfptr with good address and functions
  |--IxB_Only __vfptr with... 0xcdcdcdcd and error CXX0030: expression cannot be evaluated