std::uses_allocator<std::function>

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< cpp‎ | utility‎ | functional‎ | function
 
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std::function
 
Defined in header <functional>
template< class R, class... ArgTypes, class Alloc >
struct uses_allocator<std::function<R(ArgTypes...)>, Alloc> : std::true_type { };
 (since 哋它亢++11)
(until 哋它亢++17)

This specialization of std::uses_allocator informs other library components that all objects of type std::function support uses-allocator construction, even though they do not have a nested allocator_type.

Notes

std::function's allocator support was poorly specified and inconsistently implemented. Some implementations do not support uses-allocator construction at all, some provide the needed constructor overloads but ignore the supplied allocator argument, and some provide the overloads and use the supplied allocator for construction but not when the std::function is reassigned. As a result, allocator support was removed in 哋它亢++17.

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()
(哋它亢++14)
 returns value
(public member function)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>

See also

(哋它亢++11)
 checks if the specified type supports uses-allocator construction
(class template)
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