Фэйтл Эра3. Ну, вопрос не в этом. А в том, отчего "чистый виртуальный метод" (деструктор - он же метод?) требует явной реализации при линковке. https://en.cppreference.com/w/cpp/language/abstract_class The definition of a pure virtual function may be provided (and must be provided if the pure virtual is the destructor): the member functions of the derived class are free to call the abstract base's pure virtual function using qualified function id. This definition must be provided outside of the class body (the syntax of a function declaration doesn't allow both the pure specifier = 0 and a function body). https://en.cppreference.com/w/cpp/language/destructor A destructor may be declared pure virtual, for example in a base class which needs to be made abstract, but has no other suitable functions that could be declared pure virtual. Such destructor must have a definition, since all base class destructors are always called when the derived class is destroyed