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

| | | | | ----------------------------------------------- | | ------------- | | template< class T > struct is_bounded_array; | | (since C++20) |

std::is_bounded_array is a UnaryTypeTrait.

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

If the program adds specializations for std::is_bounded_array or std::is_bounded_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 Notes
  • 3.6 Example
  • 3.7 See also

[edit] Template parameters

[edit] Helper variable template

| template< class T > constexpr bool is_bounded_array_v = is_bounded_array<T>::value; | | (since C++20) | | ------------------------------------------------------------------------------------------- | | ------------- |

Inherited from std::integral_constant

Member constants

| | true if T is an array type of known bound, 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] Notes

[edit] Example

#include #include   #define OUT(...) std::cout << #__VA_ARGS__ << " : " << __VA_ARGS__ << '\n'   class A {};   int main() { std::cout << std::boolalpha; OUT(std::is_bounded_array_v); OUT(std::is_bounded_array_v<A[]>); OUT(std::is_bounded_array_v<A[3]>); OUT(std::is_bounded_array_v); OUT(std::is_bounded_array_v); OUT(std::is_bounded_array_v<int[]>); OUT(std::is_bounded_array_v<int[3]>); }

Output:

std::is_bounded_array_v : false std::is_bounded_array_v<A[]> : false std::is_bounded_array_v<A[3]> : true std::is_bounded_array_v : false std::is_bounded_array_v : false std::is_bounded_array_v<int[]> : false std::is_bounded_array_v<int[3]> : true

[edit] See also

| | checks if a type is an array type (class template) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | | checks if a type is an array type of unknown bound (class template) [edit] | | | obtains the size of an array type along a specified dimension (class template) [edit] |