std::is_member_function_pointer template in C++ with Examples

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

Header File:

#include<type_traits>

Template Class:

template <class T>
struct is_member_function_pointer;

Syntax:

std::is_member_function_pointer::value 

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

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

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

Below is the program to demonstrate std::is_member_function_pointer in C++:

Program 1:

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

// Declare a structure
class GFG {

public:
    int gfg;
};

class A {
};

// Driver Code
int main()
{

    // Object to class GFG
    int GFG::*pt = &GFG::gfg;
    cout << boolalpha;

    // Check if GFG* is a member function
    // pointer or not
    cout << "GFG*: "
         << is_member_function_pointer<GFG*>::value
         << endl;

    // Check if int GFG::* is a member
    // function pointer or not
    cout << "int GFG::* "
         << is_member_function_pointer<int GFG::*>::value
         << endl;

    // Check if int A::* is a member
    // function pointer or not
    cout << "int A::* "
         << is_member_function_pointer<int A::*>::value
         << endl;

    // Check if int A::*() is a member
    // function pointer or not
    cout << "int A::*() "
         << is_member_function_pointer<int (A::*)()>::value
         << endl;

    return 0;
}

Output:

GFG*: false
int GFG::* false
int A::* false
int A::*() true

Program 2:

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

// Declare a structure
struct A {
    void fn(){};
};

struct B {
    int x;
};

// Driver Code
int main()
{
    void (A::*pt)() = &A::fn;
    cout << boolalpha;

    cout << "A*: "
         << is_member_function_pointer<A*>::value
         << endl;

    cout << "void(A::*)(): "
         << is_member_function_pointer<void (A::*)()>::value
         << endl;

    cout << "B*: "
         << is_member_function_pointer<B*>::value
         << endl;

    cout << "void(B::*)(): "
         << is_member_function_pointer<void (B::*)()>::value
         << endl;

    return 0;
}

Output:

A*: false
void(A::*)(): true
B*: false
void(B::*)(): true

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