std::negation

 

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negation (C++17)

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is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)
is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
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is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)
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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> { };

See also

conjunction (C++17)	variadic logical AND metafunction (class template)
disjunction (C++17)	variadic logical OR metafunction (class template)