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

NAME
       std::is_pointer - std::is_pointer

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

	  Checks  whether  T  is  a pointer to object or a pointer to function
       (but not	a pointer
	  to member/member function) or	a cv-qualified version	thereof.  Pro-
       vides the member
	  constant  value  which  is  equal to true, if	T is a object/function
       pointer type.
	  Otherwise, value is equal to false.

	  The behavior of a program that adds specializations for is_pointer
	  or is_pointer_v
	  (since C++17)	is undefined.

Template parameters
	  T - a	type to	check

	 Helper	variable template

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

       Inherited from std::integral_constant

Member constants
	  value	   true	if T is	a pointer type , 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_pointer : std::false_type {};

	  template<class T>
	  struct is_pointer<T*>	: std::true_type {};

	  template<class T>
	  struct is_pointer<T* const> :	std::true_type {};

	  template<class T>
	  struct is_pointer<T* volatile> : std::true_type {};

	  template<class T>
	  struct is_pointer<T* const volatile> : std::true_type	{};

Example
       // Run this code

	#include <type_traits>

	int main()
	{
	    class A {};

	    static_assert(
		   not std::is_pointer<A>::value
		&&  not	 std::is_pointer_v<A>	// same	thing as above,	but in
       C++17!
		&& not std::is_pointer<A>()   // same as above,	 using	inher-
       ited operator bool
		&& not std::is_pointer<A>{}   // ditto
		&&  not	 std::is_pointer<A>()()	// same	as above, using	inher-
       ited operator()
		&& not std::is_pointer<A>{}() // ditto
		&&     std::is_pointer<A *>::value
		&&     std::is_pointer<A const * volatile>()
		&& not std::is_pointer<A &>::value
		&& not std::is_pointer<int>::value
		&&     std::is_pointer<int *>::value
		&&     std::is_pointer<int **>::value
		&& not std::is_pointer<int[10]>::value
		&& not std::is_pointer<std::nullptr_t>::value
	    );
	}

See also
	  is_member_pointer	     checks if a type is a pointer to an  non-
       static member
	  (C++11)		     function or object
				     (class template)
	  is_member_object_pointer    checks  if a type	is a pointer to	a non-
       static member
	  (C++11)		     object
				     (class template)
	  is_member_function_pointer checks if a type is a pointer to  a  non-
       static member
	  (C++11)		     function
				     (class template)
	  is_array		     checks if a type is an array type
	  (C++11)		     (class template)
	  is_scalar		     checks if a type is a scalar type
	  (C++11)		     (class template)

http://cppreference.com		  2022.07.31		    std::is_pointer(3)

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