std::uses_allocator<std::tuple>

// myalloc is a stateful Allocator with a single-argument constructor
// that takes an int. It has no default constructor.
 
    typedef std::vector<int, myalloc<int>> innervector_t;
    typedef std::tuple<int, innervector_t> elem_t;
    typedef std::scoped_allocator_adaptor< myalloc<elem_t>, myalloc<int>> Alloc;
    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

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