std::uses_allocator<std::function>
From cppreference.com
< cpp | utility | functional | function
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
Utilities library
Type support (basic types, RTTI)
Library feature-test macros (C++20)
(C++11)
(C++20)
(C++26)
(C++20)
Coroutine support (C++20)
Contract support (C++26)
(C++20)(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)(C++20)(C++20)
(C++20)(C++20)(C++20)
General utilities
Relational operators (deprecated in C++20)
(C++20)(C++20)(C++20)
(C++20)(C++20)(C++20)
(C++20)
Swap and type operations
Common vocabulary types
Function objects
(C++11)
(C++23)
(C++26)
(C++26)
(C++11)
(C++11)
(C++20)(C++23)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)(C++11)
(C++20)(C++20)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++17)
(C++17)
(C++17)
(C++17)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(until C++17*)
(until C++17*)
(until C++17*)
(until C++17*)
(until C++17*)
(until C++17*)
(until C++17*)(until C++17*)(until C++17*)(until C++17*)
(until C++20*)
(until C++20*)
(until C++17*)(until C++17*)
(until C++17*)(until C++17*)
(until C++17*)
(until C++17*)(until C++17*)(until C++17*)(until C++17*)
(until C++20*)
(until C++20*)
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 C++11) struct uses_allocator<std::function <R(ArgTypes...)>, Alloc> : std::true_type { };
(until C++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.
Contents
[edit] 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 C++17.
Inherited from std::integral_constant
Member constants
value
[static]
(public static member constant)
Member functions
operator bool
(public member function)
operator()
(C++14)
(public member function)
Member types
Type
Definition
value_type
bool
type
std::integral_constant <bool, value>