std:: derived_from
Defined in header
<concepts>
|
||
template
<
class
Derived,
class
Base
>
concept derived_from
=
|
(since C++20) | |
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
.
Example
#include <concepts> 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() {}
References
- C++23 standard (ISO/IEC 14882:2024):
-
-
18.4.3 Concept
derived_from
[concept.derived]
-
18.4.3 Concept
- C++20 standard (ISO/IEC 14882:2020):
-
-
18.4.3 Concept
derived_from
[concept.derived]
-
18.4.3 Concept
See also
(C++11)
|
checks if a type is a base of the other type
(class template) |
(C++11)
(C++20)
|
checks if a type can be converted to the other type
(class template) |