【运维经】第46章——error: overriding final function

运维经–目录

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error: overriding final function

c++11中引入了final关键字，被final修饰的函数不允许其派生类重载。

#include <iostream>

class Object
{
public:
    Object(){};
    virtual ~Object(){};

    virtual void fun()
    {
        std::cout << "Object::fun" << std::endl;
    }
};

class Base:public Object
{
public:
    Base(){};
    virtual ~Base(){};

    void fun() final;
};
void Base::fun()
{
    std::cout << "Base::fun" << std::endl;
}

class Derived : public Base
{
public:
    Derived(){};
    virtual ~Derived(){};

    void fun();
};
void Derived::fun()
{
    std::cout << "Derived::fun" << std::endl;
}    

int main(){
    // Object o;
    // o.fun();
    Object* d = new Derived;
    d->fun();
    return 0;
}

编译报错

[frank@LAPTOP-0OCJTGJR class]$ g++ -g -std=c++11 test_class.cpp
test_class.cpp:34:10: error: virtual function ‘virtual void Derived::fun()’
     void fun();
          ^
test_class.cpp:23:6: error: overriding final function ‘virtual void Base::fun()’
 void Base::fun()
      ^