class template
<type_traits>

std::has_virtual_destructor

template <class T> struct has_virtual_destructor;
Has virtual destructor

Trait class that identifies whether T has a virtual destructor.

Only the classes (declared with class, struct or union) that have a destructor explicitly declared as such (or that inherit from a class that does) have a virtual destructor.

has_virtual_destructor inherits from integral_constant as being either true_type or false_type, depending on whether T's destructor is trivial.

Template parameters

T
A complete type, or void (possible cv-qualified), or an array of unknown bound of a complete element type.
A type.
If a class type, it shall be a complete type or a union (for unions, this trait is always false).

Member types

Inherited from integral_constant:
member typedefinition
value_typebool
typeeither true_type or false_type

Member constants

Inherited from integral_constant:
member constantdefinition
valueeither true or false

Member functions

Inherited from integral_constant:
operator bool
Returns value (public member function )

Example

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// has_virtual_destructor example
#include <iostream>
#include <type_traits>

struct A { };
struct B { virtual ~B(){} };
struct C : B { };

int main() {
  std::cout << std::boolalpha;
  std::cout << "has_virtual_destructor:" << std::endl;
  std::cout << "int: " << std::has_virtual_destructor<int>::value << std::endl;
  std::cout << "A: " << std::has_virtual_destructor<A>::value << std::endl;
  std::cout << "B: " << std::has_virtual_destructor<B>::value << std::endl;
  std::cout << "C: " << std::has_virtual_destructor<C>::value << std::endl;
  return 0;
}


Output:
has_virtual_destructor:
int: false
A: false
B: true
C: true

See also

is_trivially_copyable
Is trivially copyable (class template )
is_signed
Is signed type (class template )
is_unsigned
Is unsigned type (class template )

C++

<type_traits>