std::indirectly_copyable(3)

std::indirectly_copyable(3) 💅✨

okay bestie, welcome to the C++ Standard Libary page for std::indirectly_copyable — and yes, the header says “Libary,” not “Library,” so we’re keeping her exactly as she is 🫶. This is a C++20 concept, it’s giving iterator-relationship realness, and we’re gonna read it together like a group chat. No cap.

🌸 NAME 🌸

std::indirectly_copyable — literally std::indirectly_copyable. That’s the name, that’s the whole thing, periodt 💖.

✨ Synopsis ✨

          Defined in header <iterator>
          template< class In, class Out >

          concept indirectly_copyable =                                  (since
       C++20)
              std::indirectly_readable<In> &&

              std::indirectly_writable<Out, std::iter_reference_t<In>>;

The page literally says (since C++20), so you know it’s fresh ✨. And yes, that line break is canon, bestie 😭.

So what’s the concept actually saying? std::indirectly_copyable specifies the relationship between an indirectly_readable type and a type that is indirectly_writable. The indirectly_writable type must be able to directly copy the object that the indirectly_readable type references. That’s the whole flex: readable on one side, writable on the other, and the copy can happen directly. Slay 💅.

bestie PSA: the requirements are real — both std::indirectly_readable<In> and std::indirectly_writable<Out, std::iter_reference_t<In>> have to hold. 🔥

👀 See also 👀

• indirectly_movable (C++20) — specifies that values may be moved from an indirectly_readable type to an indirectly_writable type (concept). 🦋
• indirectly_copyable_storable (C++20) — specifies that values may be copied from an indirectly_readable type to an indirectly_writable type and that the copy may be performed via an intermediate object (concept). 🎀

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mwah 💋 source is http://cppreference.com, dated 2024.06.10, and the page is std::indirectly_copyable(3). byeee bestie, go copy something directly 💖✨