std::derived_from - cppreference.com (original) (raw)

The concept derived_from<Derived, Base> is satisfied if and only if Base is a class type that is either Derived or a public and unambiguous base of Derived, ignoring cv-qualifiers.

Note that this behavior is different to std::is_base_of when Base is a private or protected base of Derived.

[edit] Example

#include   class A {};   class B : public A {};   class C : private A {};   // std::derived_from == true only for public inheritance or exact same class static_assert(std::derived_from<B, B> == true); // same class: true static_assert(std::derived_from<int, int> == false); // same primitive type: false static_assert(std::derived_from<B, A> == true); // public inheritance: true static_assert(std::derived_from<C, A> == false); // private inheritance: false   // std::is_base_of == true also for private inheritance static_assert(std::is_base_of_v<B, B> == true); // same class: true static_assert(std::is_base_of_v<int, int> == false); // same primitive type: false static_assert(std::is_base_of_v<A, B> == true); // public inheritance: true static_assert(std::is_base_of_v<A, C> == true); // private inheritance: true   int main() {}

[edit] References

[edit] See also