类具有虚拟功能和可访问的非虚拟析构函数 [英] class has virtual functions and accessible non-virtual destructor

问题描述

我有两节课:

class A {
public:
    virtual void somefunction() = 0;
};

class B : public A {
public:
    B();
    ~B();
    void somefunction();
};

B::B() {}

void B::somefunction() {
    //  some code
}

但是使用g ++会出现错误:

But with g++ I get errors:

class A has virtual functions and accessible non-virtual destructor
class B has virtual functions and accessible non-virtual destructor

我不知道这个错误是什么...在博客的某个地方，我读到这是一个编译器警告.我该如何解决该问题?

I don't have any idea what this error is... Somewhere on blogs I read that it's a compiler warning. How can I fix the problem?

推荐答案

之所以会发生这种情况，是因为您的基类A没有虚拟析构函数.例如，如果您有以下代码:

This happens because your base class A does not have a virtual destructor. For instance, if you had this code:

int main()
{
    A* a = new B;
    delete a;
}

然后，由于A不是虚拟的，因此delete a调用将无法调用B的析构函数. (这会泄漏B的所有资源.)您可以在此处详细了解虚拟析构函数.

Then the delete a call would not be able to call B's destructor because A's isn't virtual. (It would leak all of B's resources.) You can read more about virtual destructors here.

在基类中添加一个虚拟析构函数，您应该没事.

Add a virtual destructor to your base class and you should be fine.

class A
{
public:  
    virtual void somefunction() = 0;
    virtual ~A() = 0;
}

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