std::is_unbounded_array
From cppreference.com
| Defined in header <type_traits>
|
||
| template< class T > struct is_unbounded_array; |
(since C++20) | |
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 > inline constexpr bool is_unbounded_array_v = is_unbounded_array<T>::value; |
(since C++20) | |
Inherited from std::integral_constant
Member constants
| value [static] |
true if T is an array type of unknown bound , false otherwise (public static member constant) |
Member functions
| operator bool |
converts the object to bool, returns value (public member function) |
| operator() (C++14) |
returns value (public member function) |
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
See also
| (C++11) |
checks if a type is an array type (class template) |
| (C++20) |
checks if a type is an array type of known bound (class template) |
| (C++11) |
obtains the size of an array type along a specified dimension (class template) |