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

NAME
     std::is_void - std::is_void

Synopsis
	Defined in header <type_traits>
	template< class T >		 (since C++11)
	struct is_void;

	std::is_void is a UnaryTypeTrait.

	Checks whether T is a void type. Provides the member constant value that
     is equal to
	true,  if  T  is  the  type  void,  const  void, volatile void, or const
     volatile void.
	Otherwise, value is equal to false.

	If the program adds specializations for std::is_void or  std::is_void_v,
     the behavior
	is undefined.

Template parameters
	T - a type to check

	Helper variable template

	template< class T >				      (since C++17)
	inline constexpr bool is_void_v = is_void<T>::value;

     Inherited from std::integral_constant

Member constants
	value	  true if T is the type void (possibly cv-qualified), false oth-
     erwise
	[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_void :  std::is_same<void,  typename	std::remove_cv<T>::type>
     {};

Example
     // Run this code

      #include <type_traits>

      void foo();

      static_assert
      (
	  std::is_void_v<void> == true and
	  std::is_void_v<const void> == true and
	  std::is_void_v<volatile void> == true and
	  std::is_void_v<void*> == false and
	  std::is_void_v<int> == false and
	  std::is_void_v<decltype(foo)> == false and
	  std::is_void_v<std::is_void<void>> == false
      );

      int main() {}

See also
	is_array    checks if a type is an array type
	(C++11)     (class template)
	is_pointer  checks if a type is a pointer type
	(C++11)     (class template)
	is_enum     checks if a type is an enumeration type
	(C++11)     (class template)
	is_union    checks if a type is a union type
	(C++11)     (class template)
	is_class    checks if a type is a non-union class type
	(C++11)     (class template)
	is_function checks if a type is a function type
	(C++11)     (class template)
	is_object   checks if a type is an object type
	(C++11)     (class template)

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