c++ - 虚拟析构函数必须是公开的吗？

Question

我发现几乎每个虚拟析构函数的代码片段都将其作为公共(public)成员函数，如下所示:

class Base
{
public:
    virtual ~Base()
    {
        cout << "~Base()" << endl;
    }
};
class Derived : public Base
{
public:
    ~Derived()
    {
        cout << "~Derived()" << endl;
    }
};

---

虚拟析构函数必须是公共(public)的还是在某些情况下非公共(public)的虚拟析构函数才有意义？

Answer 1

Do virtual destructors have to be public or are there situations where a non-public virtual destructor makes sense?

类(class)用马。如果您需要多态删除，则使用 public 虚拟析构函数，否则您的析构函数根本不需要是虚拟的。

关注 Herb's advice :

Guideline #4: A base class destructor should be either public and virtual, or protected and nonvirtual.

In brief, then, you're left with one of two situations. Either:

1. You want to allow polymorphic deletion through a base pointer, in which case the destructor must be virtual and public; or
2. You don't, in which case the destructor should be nonvirtual and protected, the latter to prevent the unwanted usage.