智能指针的简单应用

class net_session:public boost::enable_shared_from_this<net_session>
{
public:
 net_session()
 {
  std::cout<<"net_session.\n";
 }

 ~net_session()
 {
  std::cout<<"~net_session.\n";
 }
};

 

int _tmain(int argc, _TCHAR* argv[])
{
  std::vector<boost::shared_ptr<net_session> > v_vec;
 boost::weak_ptr<net_session> weak_session_ptr; //弱引用,不增加引用计数
 if (true) //作用域
 {
  boost::shared_ptr<net_session> new_session(new net_session);
  std::cout<<"引用计数:"<<new_session.use_count()<<std::endl;
  v_vec.push_back(new_session);
  weak_session_ptr = new_session;
  std::cout<<"引用计数:"<<new_session.use_count()<<std::endl;
 }

 std::cout<<"引用计数:"<<v_vec[0].use_count()<<std::endl;
 v_vec.clear(); //执行完后,new_session引用计数减一,对象被析构
 if (weak_session_ptr.expired())
  std::cout<<"对象已经被析构.\n";
 getchar();
 return 0;
}