std::is_member_pointer in C++ with Examples

The std::is_member_pointer template of C++ STL is present in the <type_traits> header file. The std::is_member_pointer template of C++ STL is used to check whether the T is a pointer to non-static member or not. It return the boolean value true if T is a pointer to non-static member type, Otherwise return false.

Header File:

#include<type_traits>

Template Class:

template<class T>
struct is_member_pointer
     : std::integral_constant < bool,
       is_member_object_pointer<T>::value 
    || is_member_function_pointer<T>::value> {};

Syntax:

std::is_member_pointer::value

Parameters: The template std::is_member_pointer accepts a single parameter T(Trait class) to check whether T is pointer to non-static member or not.

Return Value: This template returns a boolean variable as shown below:

• True: If the type T is pointer to non-static member.
• False: If the type T is not a pointer to non-static member.

Below is the program to illustrates the std::is_member_pointer template in C/C++:

Program:

// C++ program to illustrate
// std::is_member_pointer
#include <bits/stdc++.h>
#include <type_traits>
using namespace std;

// Driver Code
int main()
{

    // Empty Class GFG
    class GFG {
    };

    // Check if GFG::* is a member
    // pointer or not
    bool a = is_member_pointer<int(GFG::*)>::value;
    if (a) {
        cout << "GFG::* is a Member Pointer!"
             << endl;
    }
    else {
        cout << "GFG::* is not a Member Pointer!"
             << endl;
    }

    // Check if int is a member
    // pointer or not
    a = is_member_pointer<int(int)>::value;
    if (a) {
        cout << "int is a Member Pointer!"
             << endl;
    }
    else {
        cout << "int is not a Member Pointer!"
             << endl;
    }

    return 0;
}

Output:

GFG::* is a Member Pointer!
int is not a Member Pointer!

Reference: http://www.cplusplus.com/reference/type_traits/is_member_pointer/