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std::is_bounded_array(3)       C++ Standard Libary	std::is_bounded_array(3)

NAME
     std::is_bounded_array - std::is_bounded_array

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

	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.

Template parameters
	T - a type to check

	Helper variable template

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

     Inherited from std::integral_constant

Member constants
	value	 true if T is an array type of known bound, false otherwise
	[static] (public static member constant)

Member functions
	operator bool converts the object to bool, returns value
		      (public member function)
	operator()    returns value
	(C++14)       (public member function)

Member types
	Type	   Definition
	value_type bool
	type	   std::integral_constant<bool, value>

Possible implementation
	template<class T>
	struct is_bounded_array : std::false_type {};

	template<class T, std::size_t N>
	struct is_bounded_array<T[N]> : std::true_type {};

Notes
	      Feature-test macro	Value	 Std		      Feature
	__cpp_lib_bounded_array_traits 201902L (C++20) std::is_bounded_array,
						       std::is_unbounded_array

Example
     // Run this code

      #include <iostream>
      #include <type_traits>

      #define OUT(...) std::cout << #__VA_ARGS__ << " : " << __VA_ARGS__ << '\n'

      class A {};

      int main()
      {
	  std::cout << std::boolalpha;
	  OUT(std::is_bounded_array_v<A>);
	  OUT(std::is_bounded_array_v<A[]>);
	  OUT(std::is_bounded_array_v<A[3]>);
	  OUT(std::is_bounded_array_v<float>);
	  OUT(std::is_bounded_array_v<int>);
	  OUT(std::is_bounded_array_v<int[]>);
	  OUT(std::is_bounded_array_v<int[3]>);
      }

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

See also
	is_array	   checks if a type is an array type
	(C++11) 	   (class template)
	is_unbounded_array checks if a type is an array type of unknown bound
	(C++20) 	   (class template)
	extent		    obtains  the size of an array type along a specified
     dimension
	(C++11) 	   (class template)

http://cppreference.com 	   2024.06.10		std::is_bounded_array(3)
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