如何定义一个只能在堆（栈）上创建对象的类

只能在栈上创建 不能new
Widget *w=new Widget;出错

class Widget : public QWidget
{
    Q_OBJECT
    
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    
private:
    Ui::Widget *ui;
    void* operator new(size_t){}
    void operator delete(void*){}
    
};

只能在堆上创建 只能new
Widget w；//出错

class Widget : public QWidget
{
    Q_OBJECT
    
public:
    explicit Widget(QWidget *parent = 0);


private:
    Ui::Widget *ui;
    ~Widget();
};