使用函数指针调用虚函数成员函数的基类定义 [英] Calling base class definition of virtual member function with function pointer

问题描述

我想使用成员函数指针调用虚函数的基类实现。

I want to call the base class implementation of a virtual function using a member function pointer.

class Base {
public:
    virtual void func() { cout << "base" << endl; }
};

class Derived: public Base {
public:
    void func() { cout << "derived" << endl; }

    void callFunc()
    {
        void (Base::*fp)() = &Base::func;
        (this->*fp)(); // Derived::func will be called.
                       // In my application I store the pointer for later use,  
                       // so I can't simply do Base::func().
    }
};

在上面的代码中，func的派生类实现将从callFunc调用。有没有办法我可以保存一个成员函数指针指向Base :: func，或者我必须使用使用以某种方式？

In the code above the derived class implementation of func will be called from callFunc. Is there a way I can save a member function pointer that points to Base::func, or will I have to use using in some way?

在我的实际应用程序中，我使用boost :: bind在callFunc中创建一个boost :: function对象，我稍后使用它从程序的另一部分调用func。所以如果boost :: bind或者boost :: function有一些方法来解决这个问题，这也有帮助。

In my actual application I use boost::bind to create a boost::function object in callFunc which I later use to call func from another part of my program. So if boost::bind or boost::function have some way of getting around this problem that would also help.

推荐答案

你通过引用或指针调用一个虚方法，你将总是激活找到最多派生类型的虚拟调用机制。

When you call a virtual method via a reference or a pointer you will always activate the virtual call mechanism that finds the most derived type.

你最好的办法是添加一个替代函数这不是虚拟的。

Your best bet is to add an alternative function that is not virtual.

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