Std::is_unbounded_array (3) Linux Manual Page

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

std::is_unbounded_array (3) Linux Manual Page