| Defined in header <type_traits> | ||
|---|---|---|
template<class B> struct negation; | (1) | (since C++17) |
Forms the logical negation of the type trait B.
The type std::negation<B> is a UnaryTypeTrait with a BaseCharacteristic of std::integral_constant<bool, !B::value>.
Template parameters
| B | - | any type such that B::value is convertible to bool |
Helper variable template
template<class B> constexpr bool negation_v = negation<B>::value; | (since C++17) |
Inherited from std::integral_constant
Member constants
| value [static] | true if B has a member ::value that is false , 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 B>
struct negation : std::bool_constant<!B::value> { }; |
Example
See also
| (C++17) | variadic logical AND metafunction (class template) |
| (C++17) | variadic logical OR metafunction (class template) |
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