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std::uses_allocator(3) C++ Standard Libary std::uses_allocator(3)

NAME

std::uses_allocator - std::uses_allocator

Synopsis


Defined in header <tuple>
template< class... Types, class Alloc >
struct uses_allocator< std::tuple<Types...>, Alloc > : std::true_type (since C++11)
{ };


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

Member constants


value true
[static] (public static member constant)

Member functions


operator bool converts the object to bool, returns value
(public member function)
operator() returns value
(C++14) (public member function)

Member types


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

Example


// myalloc is a stateful Allocator with a single-argument constructor
// that takes an int. It has no default constructor.


using innervector_t = std::vector<int, myalloc<int>>;
using elem_t = std::tuple<int, innervector_t>;
using Alloc = std::scoped_allocator_adaptor< myalloc<elem_t>, myalloc<int>>;


Alloc a(1,2);
std::vector<elem_t, Alloc> v(a);
v.resize(1); // uses allocator #1 for elements of v
std::get<1>(v[0]).resize(10); // uses allocator #2 for innervector_t

See also


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

2024.06.10 http://cppreference.com