NAME¶

std::has_virtual_destructor - std::has_virtual_destructor

Synopsis¶

Defined in header <type_traits>
template< class T > (since C++11)
struct has_virtual_destructor;

If T is a type with a virtual destructor, provides the member constant value equal
to true. For any other type, value is false.

If T is a non-union class type, T shall be a complete type; otherwise, the behavior
is undefined.

The behavior of a program that adds specializations for has_virtual_destructor
or has_virtual_destructor_v
(since C++17) is undefined.

Template parameters¶

T - a type to check

Helper variable template

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

Inherited from std::integral_constant

Member constants¶

value true if T has a virtual destructor , false otherwise
[static] (public static member constant)

Member functions¶

operator bool converts the object to bool, returns value
(public member function)
operator() returns value
(C++14) (public member function)

Member types¶

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

Notes¶

If a class has a public virtual destructor, it can be derived from, and the derived
object can be safely deleted through a pointer to the base object (GotW #18). When
true, is_polymorphic is true.

Example¶

// Run this code

#include <iostream>
#include <type_traits>
#include <string>
#include <stdexcept>

int main()
{
std::cout << std::boolalpha
<< "std::string has a virtual destructor? "
<< std::has_virtual_destructor<std::string>::value << '\n'
<< "std::runtime_error has a virtual destructor? "
<< std::has_virtual_destructor<std::runtime_error>::value << '\n';
}

Output:¶

std::string has a virtual destructor? false
std::runtime_error has a virtual destructor? true

See also¶

is_destructible
is_trivially_destructible
is_nothrow_destructible checks if a type has a non-deleted destructor
(C++11) (class template)
(C++11)
(C++11)
is_polymorphic checks if a type is a polymorphic class type
(C++11) (class template)