std::uses_allocator<std::tuple>

Since C++11

Header: <tuple>

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.

# Declarations

template< class... Types, class Alloc >
struct uses_allocator< std::tuple<Types...>, Alloc > : std::true_type { };

(since C++11)

# 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