std::is_member_object_pointer

 

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

std::is_member_object_pointer is a 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.

If the program adds specializations for std::is_member_object_pointer or std::is_member_object_pointer_v, the behavior is undefined.

Template parameters

T

-

a type to check

Helper variable template

template<class T > constexprbool 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 non-static member function pointer (class template)