编译问题，类之间相互引用。
windows   下没问题，Linux   下一直没解决啊！
程序框架如下：　

/**
* 文件名: MessageFactory.h
**/
#ifndef   MessageFactory_h
#define   MessageFactory_h

#include   "MessageServer.h "

class   MessageServer   ;

class   MessageFactory
{
public:
MessageFactory(void){}

virtual   ~MessageFactory(void){}

virtual   void   CreateReceiver(int   code,   MessageServer*   server)   =   0;
};

#endif  


/**
* 文件名: MessageFactoryImpl.h
**/
#ifndef   MessageFactoryImpl_h
#define   MessageFactoryImpl_h

#include   "MessageFactory.h "
 
class   MessageFactoryImpl   :public   MessageFactory
{

public:
MessageFactoryImpl();
virtual   ~MessageFactoryImpl(){}
   
        virtual   void   CreateReceiver(int   code,   MessageServer*   server);
};
#endif

/**
* 文件名: MessageFactoryImpl.cpp
**/

#include   "MessageFactoryImpl.h "

MessageFactoryImpl::MessageFactoryImpl()
{
}
   
void   MessageFactoryImpl::CreateReceiver(int   code,   MessageServer*   server)
{
}

 
/**
* 文件名: MessageServer.h
**/
#ifndef   MessageServer_h
#define   MessageServer_h

#include   "MessageFactory.h "

class   MessageFactory   ;

class   MessageServer
{
public:
  MessageServer();
MessageServer(int   udpPort,   MessageFactory*   factory,   long   timeout);
virtual   ~MessageServer();
 
};
#endif

/**
* 文件名: MessageServer.cpp
**/

#include   "MessageServer.h "  
 
MessageServer::MessageServer()
{

}
 
MessageServer::MessageServer(int   udpPort,   MessageFactory*   factory,   long   timeout)
{
}
 
MessageServer::~MessageServer()
{
}  

//:test.cpp
#include   <iostream>

#include   "MessageFactoryImpl.h "
#include   "MessageServer.h "

using   namespace   std;

int   main()
{

MessageFactoryImpl   *a=new   MessageFactoryImpl();

MessageServer   *b=new   MessageServer();

cout < < "it 's   ok " < <endl;

delete   a;
delete   b;

return   0;
}


#   makefile
test:   MessageFactoryImpl.o   MessageServer.o  
g++     test.cpp         -o   test

MessageFactoryImpl.o:   MessageFactoryImpl.h   MessageFactory.h   \
                                            MessageServer.o  
g++   -c   MessageFactoryImpl.cpp

MessageServer.o:   MessageFactory.h   MessageServer.h  
g++   -c   MessageServer.cpp  




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