小编Yuv*_*lon的帖子

我有以下类尝试实现通用的Singleton.

struct BaseObject
{
   virtual ~BaseObject() {}
};
class _helper
{
private:
    template<typename T> friend class Singleton;
    set<BaseObject*> _s;
    static _helper& _get()
    {
        static _helper t;
        return t;
    }
    _helper()
    {
        cout<<" _helper ctor"<<endl;
    }
    ~_helper()
    {
        cout<<" _helper dtor"<<endl;
        //assert(_s.empty());
    }
};

// Singleton<foo>::Instance() returns a unique instance of foo
template <typename T>
class Singleton : virtual private T
{
public:
    static T& Instance()
    {
        static Singleton<T> _T;
        return _T;
    } 

private:
    Singleton()
    {
        cout<<"inserting into helper "<<typeid(T).name()<<" ptr …