std:: uses_allocator <std::tuple>

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C++
Utilities library
General utilities
Relational operators (deprecated in C++20)
std::tuple
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 .

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 >

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

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