std::is_unbounded_array (3) - Linux Manuals

std::is_unbounded_array: std::is_unbounded_array

NAME

std::is_unbounded_array - std::is_unbounded_array

Synopsis

Defined in header <type_traits>
template< class T > (since C++20)
struct is_unbounded_array;

Checks whether T is an array_type_of_unknown_bound. Provides the member constant value which is equal to true, if T is an array type of unknown bound. Otherwise, value is equal to false.

Template parameters

T - a type to check

Helper variable template

template< class T > (since C++20)
inline constexpr bool is_unbounded_array_v = is_unbounded_array<T>::value;

Inherited from std::integral_constant

Member constants

value true if T is an array type of unknown bound , 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>

Possible implementation

  template<class T>
  struct is_unbounded_array: std::false_type {};

  template<class T>
  struct is_unbounded_array<T[]> : std::true_type {};

Example

// Run this code

  #include <iostream>
  #include <type_traits>

  class A {};

  int main()
  {
      std::cout << std::boolalpha;
      std::cout << std::is_unbounded_array_v<A> << '\n';
      std::cout << std::is_unbounded_array_v<A[]> << '\n';
      std::cout << std::is_unbounded_array_v<A[3]> << '\n';
      std::cout << std::is_unbounded_array_v<float> << '\n';
      std::cout << std::is_unbounded_array_v<int> << '\n';
      std::cout << std::is_unbounded_array_v<int[]> << '\n';
      std::cout << std::is_unbounded_array_v<int[3]> << '\n';
  }

Output:

  false
  true
  false
  false
  false
  true
  false