std::scoped...ator_adaptor(3)

hey bestie 🫶 you're on the std::scoped...ator_adaptor(3) page from the C++ Standard Libary (that's the manual name, typed exactly like that here 💅), and we're about to make these constructors make sense. no cap. ✨

🌸 NAME 🌸

std::scoped_allocator_adaptor::scoped_allocator_adaptor — the constructor for std::scoped_allocator_adaptor, and yes its name is literally std::scoped_allocator_adaptor::scoped_allocator_adaptor again. iconic echo behavior 😭💖

✨ Synopsis ✨

Defined in header <scoped_allocator>.

scoped_allocator_adaptor(); // (1) (since C++11)

template< class OuterA2 >
scoped_allocator_adaptor(
    OuterA2&& outerAlloc, const InnerAllocs&... innerAllocs
) noexcept; // (2) (since C++11)

scoped_allocator_adaptor(
    const scoped_allocator_adaptor& other
) noexcept; // (3) (since C++11)

scoped_allocator_adaptor(
    scoped_allocator_adaptor&& other
) noexcept; // (4) (since C++11)

template< class OuterA2 >
scoped_allocator_adaptor(
    const scoped_allocator_adaptor<OuterA2, InnerAllocs...>& other
) noexcept; // (5) (since C++11)

template< class OuterA2 >
scoped_allocator_adaptor(
    scoped_allocator_adaptor<OuterA2, InnerAllocs...>&& other
) noexcept; // (6) (since C++11)

Now the six overloads, in order, no skipping, bestie:

1. Default constructor: value-initializes the OuterAlloc base class and the inner allocator member object, if used by the implementation. (since C++11)
2. Constructs the base class OuterAlloc from std::forward<OuterA2>(outerAlloc), and the inner allocators with innerAllocs.... This overload participates in overload resolution only if std::is_constructible<OuterAlloc, OuterA2>::value is true. (since C++11)
3. Copy-constructor: initializes each allocator from the corresponding allocator of other. (since C++11)
4. Move-constructor: moves each allocator from the corresponding allocator of other into *this. (since C++11)
5. Initializes each allocator from the corresponding allocator of other. This overload participates in overload resolution only if std::is_constructible<OuterAlloc, const OuterA2&>::value is true. (since C++11)
6. Initializes each allocator from the corresponding allocator of other, using move semantics. This overload participates in overload resolution only if std::is_constructible<OuterAlloc, OuterA2>::value is true. (since C++11)

💅 Parameters 💅

• outerAlloc — constructor argument for the outer allocator. 🫶
• innerAllocs... — constructor arguments for the inner allocators. ✨
• other — another std::scoped_allocator_adaptor. 💖

🩹 Defect reports 🩹

The following behavior-changing defect reports were applied retroactively to previously published C++ standards. lowkey important to know 🧚

• DR: LWG 2782 — Applied to: C++11 — Behavior as published: constructors taking OuterA2 weren't constrained, interfering with metaprogramming — Correct behavior: constraint added. 💀✨

👀 See also 👀

• allocate — allocates uninitialized storage using the outer allocator (public member function).
• construct — constructs an object in allocated storage, passing the inner allocator to construct its constructor if appropriate (public member function).

mwah 💋 that's the whole page, bestie. sourced from http://cppreference.com, version/date 2024.06.10, and the page is std::scoped...ator_adaptor(3). slay 🎀