The Curiously Recurring Template Pattern (CRTP)

Snippet

The Curiously Recurring Template Pattern (CRTP)

CRTP is a technique where a class derives from a template instantiation using itself as an argument. It enables static polymorphism (compile-time dispatch), which avoids the overhead of virtual function tables (vtable).

snippet.cpp

cpp

template <typename Derived>
class Base {
public:
    void interface() {
        static_cast<Derived*>(this)->implementation();
    }
};
 
class Derived : public Base<Derived> {
public:
    void implementation() { /* ... */ }
};

Breakdown

static_cast<Derived*>(this)

Casts the base pointer to the derived type to access specific implementations at compile time.

class Derived : public Base<Derived>

The 'Curiously Recurring' part: the class passes itself to its own base.

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The Curiously Recurring Template Pattern (CRTP)

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