Std::is_final (3) Linux Manual Page

std::is_final – std::is_final

Synopsis

Defined in header<type_traits>

    template <class T>
    (since C++ 14)

        struct is_final;

If T is a final class (that is, a class declared with the final_specifier), provides the member constant value equal true. For any other type, value is false.
If T is a class type, T shall be a complete type; otherwise, the behavior is undefined.

Template parameters

T – a type to check

Helper variable template

template< class T > (since C++17)
inline constexpr bool is_final_v = is_final<T>::value;

Inherited from std::integral_constant

Member constants

value true if T is a final class type , false otherwise
(public static member constant)
[static]

Member functions

converts the object to bool, returns value
operator bool (public member function)

operator() returns value
(public member function)
(C++14)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>

Notes

Final classes cannot be used as base classes.
A union can be marked final (and std::is_final will detect that), even though unions cannot be used as bases in any case.

Example

// Run this code

#include <iostream>

#include <type_traits>
class A
{
};

class B final
{
};
int main()

{
    std::cout
        << std::boolalpha
        << std::is_final<A>::value << '\n'
        << std::is_final<B>::value << '\n';
}

Output:

false
true

std::is_final (3) Linux Manual Page