std::is_pointer (3) - Linux Man Pages

std::is_pointer: std::is_pointer

NAME

std::is_pointer - std::is_pointer

Synopsis


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


Checks whether T is a pointer_to_object or a pointer to function (but not a pointer to member/member function). Provides the member constant value which is equal to true, if T is a object/function pointer type. Otherwise, value is equal to false.

Template parameters


T - a type to check


Helper variable template


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


Inherited from std::integral_constant

Member constants


value true if T is a pointer type , false otherwise
         (public static member constant)
[static]

Member functions


              converts the object to bool, returns value
operator bool (public member function)


operator() returns value
              (public member function)
(C++14)

Member types


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

Possible implementation


  template< class T > struct is_pointer_helper : std::false_type {};
  template< class T > struct is_pointer_helper<T*> : std::true_type {};
  template< class T > struct is_pointer : is_pointer_helper<typename std::remove_cv<T>::type> {};

Example


// Run this code


  #include <iostream>
  #include <type_traits>


  class A {};


  int main()
  {
      std::cout << std::boolalpha;
      std::cout << std::is_pointer<A>::value << '\n';
      std::cout << std::is_pointer<A *>::value << '\n';
      std::cout << std::is_pointer<A &>::value << '\n';
      std::cout << std::is_pointer<int>::value << '\n';
      std::cout << std::is_pointer<int *>::value << '\n';
      std::cout << std::is_pointer<int **>::value << '\n';
      std::cout << std::is_pointer<int[10]>::value << '\n';
      std::cout << std::is_pointer<std::nullptr_t>::value << '\n';
  }

Output:


  false
  true
  false
  false
  true
  true
  false
  false

See also


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


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


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


is_array checks if a type is an array type
                           (class template)
(C++11)


is_scalar checks if a type is a scalar type
                           (class template)
(C++11)