std::is_member_function_pointer

template< class T >
struct is_member_function_pointer;

std::is_member_function_pointer is a UnaryTypeTrait.

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

The behavior of a program that adds specializations for std::is_member_function_pointer or std::is_member_function_pointer_v is undefined.

Template parameters

Helper variable template

template< class T >
inline constexpr bool is_member_function_pointer_v =
    is_member_function_pointer<T>::value;

Possible implementation

template<class T>
struct is_member_function_pointer_helper : std::false_type {};
 
template<class T, class U>
struct is_member_function_pointer_helper<T U::*> : std::is_function<T> {};
 
template<class T>
struct is_member_function_pointer 
    : is_member_function_pointer_helper<typename std::remove_cv<T>::type> {};

Example

#include <type_traits>
 
class A
{
public:
    void member() {}
};
 
int main()
{
    // fails at compile time if A::member is a data member and not a function
    static_assert(std::is_member_function_pointer<decltype(&A::member)>::value,
                  "A::member is not a member function."); 
}

See also