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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;

	std::is_pointer is a UnaryTypeTrait.

	Checks	whether  T is a pointer to object or function (including pointer
     to void, but
	excluding pointer to member) or a cv-qualified version thereof. Provides
     the member
	constant value which is equal  to  true,  if  T  is  an  object/function
     pointer type.
	Otherwise, value is equal to false.

	If   the   program   adds   specializations   for   std::is_pointer   or
     std::is_pointer_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_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()
      {
	  struct A
	  {
	      int m;
	      void f() {}
	  };

	  int A::*mem_data_ptr = &A::m;     // a pointer to member data
	  void (A::*mem_fun_ptr)() = &A::f; // a pointer to member function

	  static_assert(
		 ! std::is_pointer<A>::value
	      && ! std::is_pointer_v<A>    // same thing as above, but in C++17!
	      && ! std::is_pointer<A>()    // same as above, using inherited op-
     erator bool
	      && ! std::is_pointer<A>{}    // ditto
	      && ! std::is_pointer<A>()()  // same as above, using inherited op-
     erator()
	      && ! std::is_pointer<A>{}()  // ditto
	      &&   std::is_pointer_v<A*>
	      &&   std::is_pointer_v<A const* volatile>
	      && ! std::is_pointer_v<A&>
	      && ! std::is_pointer_v<decltype(mem_data_ptr)>
	      && ! std::is_pointer_v<decltype(mem_fun_ptr)>
	      &&   std::is_pointer_v<void*>
	      && ! std::is_pointer_v<int>
	      &&   std::is_pointer_v<int*>
	      &&   std::is_pointer_v<int**>
	      && ! std::is_pointer_v<int[10]>
	      && ! std::is_pointer_v<std::nullptr_t>
	      &&   std::is_pointer_v<void (*)()>
	  );
      }

See also
	is_member_pointer	   checks if a type is a pointer to a 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 	   2024.06.10		      std::is_pointer(3)
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