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copied!<p>I think the big problem in this is that you think you want to do one thing, when in reality you actually want to do something else. Strange, huh?</p> <blockquote> <p>Is it permissible to construct a reference to Derived from *this before the class has been initialised?</p> </blockquote> <p>Yes, as long as you don't <strong>use</strong> it (for anything but storing a reference to it) in the scope of the Base constructor and remember in ~Base that Derived is destroyed before Base.</p> <p>But why on earth do you think that Base wants to know of Derived? If it's static polymorphism you are after, then the <a href="http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern" rel="nofollow">curiously recurring template pattern</a> is what you want:</p> <pre><code>template <typename T> class Base {}; class Derived : public Base<Derived> {}; </code></pre> <p>But I don't really think that's what you're aiming at.</p> <p>Maybe you want a way for Base to communicate with a client and think that should be done with inheritance? If so, then this observer-ish idiom is what you need:</p> <pre><code>class Client { public: virtual void Behavior() = 0; protected: ~Client() {} }; class Base { Client& client_; public: Base(Client& client) : client_(client) {} }; class Implementor : public Client { public: Implementor() : Base(*this) {} virtual void Behavior() { ... } }; </code></pre> <p>If not even that is what you want, then you need to rethink your design.</p>

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