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

NAME
     std::is_unbounded_array - std::is_unbounded_array

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

	std::is_unbounded_array is a UnaryTypeTrait.

	Checks whether T is an arrays of unknown bound. Provides the member con-
     stant value
	which  is  equal to true, if T is an array type of unknown bound. Other-
     wise, value is
	equal to false.

	If the program adds specializations for std::is_unbounded_array or
	std::is_unbounded_array_v, the behavior is undefined.

Template parameters
	T - a type to check

	Helper variable template

	template< class T >
	inline	      constexpr        bool	   is_unbounded_array_v        =
     (since C++20)
	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
	[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_unbounded_array: std::false_type {};

	template<class T>
	struct is_unbounded_array<T[]> : 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 <type_traits>

      class A {};

      static_assert
      (""
	  && std::is_unbounded_array_v<A> == false
	  && std::is_unbounded_array_v<A[]> == true
	  && std::is_unbounded_array_v<A[3]> == false
	  && std::is_unbounded_array_v<float> == false
	  && std::is_unbounded_array_v<int> == false
	  && std::is_unbounded_array_v<int[]> == true
	  && std::is_unbounded_array_v<int[3]> == false
      );

      int main() {}

See also
	is_array	 checks if a type is an array type
	(C++11) 	 (class template)
	is_bounded_array checks if a type is an array type of known bound
	(C++20) 	 (class template)
	extent		 obtains the size of an array type along a specified di-
     mension
	(C++11) 	 (class template)

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