析构函数可以是最终的吗?

May a destructor be final?

C++ 标准是否允许将析构函数声明为 final?像这样:

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

如果是这样,是否会阻止派生的声明 class:

 class FurtherDerived: public Derived {// allowed?
 }

如果允许,编译器是否会发出警告?将析构函数声明为 final 是否是指示 class 不打算用作基础 class 的可行习语?

(有no point in doing this in a ultimate base class,只有一个派生class。)

May a C++ destructor be declared as final?

是的。

And if so, does that prevent declaration of a derived class:

是的,因为派生的 class 必须声明一个析构函数(由您显式声明或由编译器隐式声明),并且该析构函数将覆盖声明的 final 函数,即格式错误。

规则是[class.virtual]/4:

If a virtual function f in some class B is marked with the virt-specifier final and in a class D derived from B a function D​::​f overrides B​::​f, the program is ill-formed.

推导本身是病式的,不必使用它。

Is declaring a destructor to be final a workable idiom for indicating that a class is not intended to be used as a base class?

有效,但你应该只标记class final。它更明确一些。