真实的C++单例模式举例

 1 class IOCP
 2 {
 3 private:
 4      IOCP()
 5      {
 6           //创建完成端口(备注:OS维护的一个队列,OS把i/o操作已经完成的事件通知放到这里)的句柄
 7           if ((m_hIOCP = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, NULL, 0)) == NULL)     
 8                ;
 9           //创建工作线程，用来处理完成端口消息的  
10           m_hWorkerThread = CreateThread(NULL, 0, WorkThread, (LPVOID)this, 0, &m_workerThreadID); 
11      };
12      ~IOCP();
13 private:
14      static IOCP* m_instance;
15 public:
16      static IOCP* Instance()
17      {
18           if( m_instance == NULL )
19           {
20                m_instance = new IOCP();
21           }
22           return m_instance;
23      }
24      void Wait();
25      static DWORD __stdcall WorkThread(LPVOID Param); 
26      HANDLE m_hIOCP; //完成端口的句柄 
27 private: 
28      HANDLE m_hWorkerThread; //工作线程句柄 
29      DWORD m_workerThreadID; 
30 public:
31      //将套接字绑定到完成端口
32      bool RegisterToCompletionPort( SOCKET socket , void* completionKey);
33 };