std::is_null_pointer
From cppreference.com
| Defined in header <type_traits>
|
||
| template< class T > struct is_null_pointer; |
(since C++14) | |
Checks whether T is the type std::nullptr_t.
Provides the member constant value that is equal to true, if T is the type std::nullptr_t, const std::nullptr_t, volatile std::nullptr_t, or const volatile std::nullptr_t.
Otherwise, value is equal to false.
Contents |
[edit] Template parameters
| T | - | a type to check |
Inherited from std::integral_constant
Member constants
| value [static] |
true if T is the type std::nullptr_t (possibly cv-qualified) , false otherwise (public static member constant) |
Member functions
| operator bool |
converts the object to bool, returns value (public member function) |
Member types
| Type | Definition |
value_type
|
bool
|
type
|
std::integral_constant<bool, value> |
[edit] Notes
std::is_pointer is false for std::nullptr_t because it is not a built-in pointer type.
[edit] Example
Run this code
#include <iostream> #include <type_traits> int main() { std::cout << std::boolalpha << std::is_null_pointer< decltype(nullptr) >::value << ' ' << std::is_null_pointer< int* >::value << '\n' << std::is_pointer< decltype(nullptr) >::value << ' ' << std::is_pointer<int*>::value << '\n'; }
Output:
true false false true
[edit] See also
| (C++11) |
checks if a type is void (class template) |
| (C++11) |
checks if a type is an array type (class template) |
| (C++11) |
checks if a type is a pointer type (class template) |
| (C++11) |
checks if a type is an enumeration type (class template) |
| (C++11) |
checks if a type is an union type (class template) |
| (C++11) |
checks if a type is a class type (but not union type) (class template) |
| (C++11) |
checks if a type is a function type (class template) |
| (C++11) |
checks if a type is object type (class template) |