std::is_member_pointer

< cpp‎ | types

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

std::is_member_pointer is an UnaryTypeTrait.

If T is pointer to non-static member object or a pointer to non-static 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 std::is_member_pointer or std::is_member_pointer_v (since C++17) is undefined.

Template parameters

a type to check

Helper variable template

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

Inherited from std::integral_constant

Member constants

value

[static]

true if T is a member pointer type, 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_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

#include <type_traits>
 
class C {};
static_assert(std::is_member_pointer_v<int(C::*)>);
 
static_assert(!std::is_member_pointer_v<int>);
 
int main()
{
}

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