如何正确地从析构函数不是虚拟的基类继承? [英] How to correctly inherit from a base class whose destructor is not virtual?

问题描述

我想从类A继承，但是A的析构函数不是虚拟的，因此我无法修改A的定义.如何避免以下情况?

I want to inherit from class A, but A's destructor is not virtual and I cannot modify A's definition. How to avoid the following case?

struct A
{
    A()
        : a(new char[8])
    {}

    ~A()
    {
        delete[] a;
    }

    char* a;
}

struct B : A
{
    B()
        : A(), b(new char[8])
    {}

    ~B()
    {
        delete[] b;
    }

    char* b;
};

int main()
{
    A* p_a = new B;
    delete p_a; // How to avoid such a dangerous deletion?
}

推荐答案

如果基类没有虚拟析构函数，并且您无法修改类定义，那么您很不走运.根据一般经验，您可能不应该将公共继承与没有虚拟析构函数的基类一起使用.

If the base class doesn't have a virtual destructor and you can't modify the class definition, you're pretty much out of luck. As a general rule of thumb, you probably shouldn't use public inheritance with a base class that doesn't have a virtual destructor.

也许您可以尝试使用合成而不是继承?将A的实例放在B中，并提供用于包装对A成员函数的调用的公共成员函数.

Maybe you can try using composition instead of inheritance? Place an instance of A in B, and provide public member functions that wrap calls to member functions of A.

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