What's the purpose of this pattern? What is it called? It looked very strange when I saw it the first time, though I have now seen it many times.
template<typename Derived>
struct Base {
//...
};
struct Example : Base<Example> {
//...
};
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Thomson
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It's called the Curiously Recurring Template pattern, and allows for static polymorphism.
It's useful when you want to add functionality to a specific class, but want the utility to be usable in a generic case. By making the utility dependent on and use a template parameter, you can achieve both.
GManNickG
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Curiously Recurring Template Pattern, or CRTP as we call it.
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1First answer by 4 seconds; you guys are slacking! – Oct 27 '10 at 05:47
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@Thomson Tan: Note carefully about @GMan's point about static polymorphism. That's an important point. It provides for simulating virtual function calls from the base class without the overhead of virtual functions (if that is important) – Chubsdad Oct 27 '10 at 07:44