[C++] Problema DLL e factory

[giuseppe500]

grazie Shodan.

il mio problema adesso è questo:
ho inserito le interfacce nel seguente file:

class CBeamDSChess;
class CEntityDS;

#include "stdafx.h"
#include "Factory1.h"
#include <map>

class CBeamDSChess;
class CEntityDS;

typedef CEntityDS* (*BASE_CREATE_FN)();

class CFactory1Impl : public CFactory1
{
   public:
      CFactory1Impl(void) {}
      ~CFactory1Impl(void) {}
      static bool InizializedMap;
      static CFactory1Impl* instance_ptr ;
      static CFactory1Impl* get_instance() {
         if (instance_ptr == NULL) {
            instance_ptr = new CFactory1Impl();
         }
         return instance_ptr;
      }
	  CEntityDS * CreateDS( int idOfObjectToCreate );
	  std::map<int, BASE_CREATE_FN>  m_pMapRegister;
};

CFactory1Impl* CFactory1Impl::instance_ptr;


CEntityDS* CFactory1Impl::CreateDS( int idOfObjectToCreate ) {
	
	BASE_CREATE_FN fz = m_pMapRegister[0] = CBeamDSChess::instance;
		return fz();
   return 0; 
}

extern "C" {
     __declspec(dllexport)CFactory1* FactoryDS() {
		
		 CFactory1Impl::m_pMapRegister[0] = CBeamDSChess::instance;

	    return CFactory1Impl::instance_ptr;
      }
      
}

nel .h:

#pragma once
class  CEntityDS;// classe interfaccia.

class CFactory1
{
public:
    virtual CEntityDS * CreateDS( int idOfObjectToCreate );
};

extern "C" {
 __declspec(dllexport)CFactory1* FactoryDS();
}

l'errore è questo:

c:\testdatasetcmpimportapi\CmpFrg\Factory1.cpp(32) : error C2065: 'instance' : undeclared identifier
c:\testdatasetcmpimportapi\CmpFrg\Factory1.cpp(32) : error C2027: use of undefined type 'CBeamDSChess'

pardon , nel file CBeamDSChess ho una funzione statica

static CEntityDS* instance(){return new CBeamDSChess();}


il casino puo essere nato dal fatto che la mia classe ase è CEntityDS e le derivate derivano da questa, anche CBeamDSChess.


grazie ancora