# std::is_member_object_pointer

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< cpp‎ | types

Defined in header `<type_traits>` |  |
template< class T > struct is_member_object_pointer; |  | (since C++11)

`std::is_member_object_pointer` is an UnaryTypeTrait.

Checks whether `T` is a non-static member object pointer. Provides the member constant `value` which is equal to true, if `T` is a non-static member object pointer type. Otherwise, `value` is equal to false.

The behavior of a program that adds specializations for `std::is_member_object_pointer` or `std::is_member_object_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_object_pointer_v = is_member_object_pointer<T>::value; |  | (since C++17)

## Inherited from std::integral_constant

### Member constants

value [static] | true if `T` is a pointer to member object, false otherwise (public static member constant)

### Member functions

operator bool | converts the object to bool, returns value (public member function)
operator() (C++14) | returns value (public member function)

### Member types

Type | Definition
`value_type` | bool
`type` | std::integral_constant<bool, value>

### Possible implementation

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

### Example

Run this code

    #include <iostream>
    #include <type_traits>

    int main()
    {
        class C {};
        std::cout << "Is member object pointer?\n" << std::boolalpha
                  << std::is_member_object_pointer_v<int(C::*)>
                  << ": int(C::*)\n"
                  << std::is_member_object_pointer_v<int(C::*)()>
                  << ": int(C::*)()\n";
    }

Output:

    Is member object pointer?
    true: int(C::*)
    false: int(C::*)()

### See also

is_pointer (C++11) | checks if a type is a pointer type (class template)
is_member_pointer (C++11) | checks if a type is a pointer to a non-static member function or object (class template)
is_member_function_pointer (C++11) | checks if a type is a pointer to a non-static member function (class template)

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