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

NAME
       std::is_member_pointer -	std::is_member_pointer

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

	  If T is pointer to non-static	member object or a pointer to non-sta-
       tic member
	  function,  provides  the  member  constant value equal true. For any
       other type, value
	  is false.

	  The behavior of a program  that  adds	 specializations  for  is_mem-
       ber_pointer
	  or is_member_pointer_v
	  (since C++17)	is undefined.

Template parameters
	  T - a	type to	check

	 Helper	variable template

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

       Inherited from std::integral_constant

Member constants
	  value	   true	if T is	a member 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_member_pointer_helper	  : std::false_type {};

	  template< class T, class U >
	  struct is_member_pointer_helper<T U::*> : std::true_type {};

	  template< class T >
	  struct is_member_pointer :
	      is_member_pointer_helper<typename	std::remove_cv<T>::type> {};

Example
       // Run this code

	#include <iostream>
	#include <type_traits>

	int main() {
	    class cls {};
	    std::cout << (std::is_member_pointer<int(cls::*)>::value
			     ? "T is member pointer"
			     : "T is not a member pointer") << '\n';
	    std::cout << (std::is_member_pointer<int>::value
			     ? "T is member pointer"
			     : "T is not a member pointer") << '\n';
	}

Output:
	T is member pointer
	T is not a member pointer

See also
	  is_pointer		     checks if a type is a pointer type
	  (C++11)		     (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)

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

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