std::is_final
From cppreference.com
| Defined in header <type_traits>
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||
| template< class T > struct is_final; |
(since C++14) | |
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 > inline constexpr bool is_final_v = is_final<T>::value; |
(since C++17) | |
Inherited from std::integral_constant
Member constants
| value [static] |
true if T is a final class type , false otherwise (public static member constant) |
Member functions
| operator bool |
converts the object to bool, returns value (public member function) |
| operator() (C++14) |
returns value (public member function) |
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
See also
| (C++11) |
checks if a type is a non-union class type (class template) |
| (C++11) |
checks if a type is a polymorphic class type (class template) |