| Defined in header <type_traits> | ||||
|---|---|---|---|---|
| (since C++11) |
Checks whether T is a void type. Provides the member constant value that is equal to true, if T is the type void, const void, volatile void, or const volatile void. Otherwise, value is equal to false.
Template parameters
| T | - | a type to check |
Helper variable template
| (since C++17) |
Inherited from std::integral_constant
Member constants
| value [static] | true if T is the type void (possibly cv-qualified) , 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
|
Example
1 2 3 4 5 6 7 8 9 | #include <iostream>#include <type_traits> int main() { std::cout << std::boolalpha; std::cout << std::is_void<void>::value << '\n'; std::cout << std::is_void<int>::value << '\n';} |
Output:
1 2 | truefalse |
See also
| (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 non-union class 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) |
| std::experimental::is_void_v
(library fundamentals TS) | variable template alias of std::is_void::value (variable template) |
Please login to continue.