std::uses_allocator<std::variant>
std::uses_allocator<std::variant>
template <class... Types, class Alloc>
struct uses_allocator<std::variant<Types...>, Alloc> : std::true_type { };
| (since C++17) |
Provides a specialization of the std::uses_allocator type trait for std::variant to inform other library components that variant can be constructed with an allocator, even though it does not have a nested allocator_type.
| Type requirements | ||
-Alloc must meet the requirements of Allocator. |
Inherited from std::integral_constant
Member constants
| value
[static] | true (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> |
Notes
The std::variant itself does not use allocators, it passes then through to the constructors of the contained values.
Example
See also
|
(C++11) | checks if the specified type supports uses-allocator construction (class template) |
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