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. |
| value
[static]
| true (public static member constant) |
| operator bool | converts the object to bool, returns value (public member function) |
| operator()
(C++14)
| returns value (public member function) |
| Type | Definition |
|---|---|
value_type | bool |
type | std::integral_constant<bool, value> |
The std::variant itself does not use allocators, it passes then through to the constructors of the contained values.
| (C++11)
| checks if the specified type supports uses-allocator construction (class template) |
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