std::is_array - cppreference.com (original) (raw)

| | | | | -------------------------------------- | | ------------- | | template< class T > struct is_array; | | (since C++11) |

std::is_array is a UnaryTypeTrait.

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

If the program adds specializations for std::is_array or std::is_array_v, the behavior is undefined.

Contents

• 1 Template parameters
• 2 Helper variable template
• 3 Inherited from std::integral_constant
  • 3.1 Member constants
  • 3.2 Member functions
  • 3.3 Member types
  • 3.4 Possible implementation
  • 3.5 Example
  • 3.6 See also

[edit] Template parameters

[edit] Helper variable template

| template< class T > constexpr bool is_array_v = is_array<T>::value; | | (since C++17) | | ------------------------------------------------------------------------- | | ------------- |

Inherited from std::integral_constant

Member constants

| | true if T is an array type, false otherwise (public static member constant) | | ------------------------------------------------------------------------------ |

Member functions

| | converts the object to bool, returns value (public member function) | | ---------------------------------------------------------------------- | | | returns value (public member function) |

Member types

[edit] Possible implementation

[edit] Example

#include #include   class A {}; static_assert(std::is_array::value == false); static_assert(std::is_array<A[]>::value == true); static_assert(std::is_array<A[3]>::value == true);   static_assert(std::is_array::value == false); static_assert(std::is_array::value == false); static_assert(std::is_array<int[]>::value == true); static_assert(std::is_array<int[3]>::value == true); static_assert(std::is_array<std::array<int, 3>>::value == false);   int main() {}

[edit] See also