<type_traits>

class template
<type_traits>

std::is_copy_constructible

template <class T> struct is_copy_constructible;
Is copy constructible

Trait class that identifies whether T is a copy constructible type.

A copy constructible type is a type that can be constructed from a value or reference of the same type. This includes scalar types and copy constructible classes.

A copy constructible class is a class that has a copy constructor (either its implicit constructor or a custom defined one).

The is_copy_constructible class inherits from integral_constant as being either true_type or false_type, depending on whether T is copy constructible.

Template parameters

T
A complete type, or void (possible cv-qualified), or an array of unknown bound.

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:

Example

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

struct A { };
struct B { B(B&&){} };
struct C { C(const C&){} };

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


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

See also