std:: is_member_function_pointer

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

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 .

If the program adds specializations for std::is_member_function_pointer or std::is_member_function_pointer_v , the behavior is undefined.

Template parameters

T - a type to check

Helper variable template

template < class T >

constexpr bool is_member_function_pointer_v =

is_member_function_pointer < T > :: value ;
(since C++17)

Inherited from std:: integral_constant

Member constants

value
[static]
true if T is a member function 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_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

Run this code 
#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

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