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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. Pro-
       vides 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
       operator	bool
		&& ! std::is_pointer<A>{}    //	ditto
		&& ! std::is_pointer<A>()()  //	same as	above, using inherited
       operator()
		&& ! 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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