std::experi...nstructible(3)

💅 std::experimental::ranges::MoveConstructible

okay so bestie, welcome to the <span>... jk, it's just std::experimental::ranges::MoveConstructible, page 3 of the C++ Standard Libary man pages 🎀 (yes that's how the libary spells it, don't come for me 💀). Sit down, grab a strawberry drink 🍓, and let's get into it.

✨ NAME ✨

std::experimental::ranges::MoveConstructible — literally the exact same thing again, <pink>std::experimental::ranges::MoveConstructible</pink> 💖 (name so nice they said it twice, iconic behavior tbh 👑)

🌸 Synopsis 🌸

First things first, this whole vibe lives in the header:

#include <experimental/ranges/concepts>

and it's shaped like this:

template< class T >
concept bool MoveConstructible =                  (ranges TS)
    Constructible<T, T> && ConvertibleTo<T, T>;

No cap, the concept MoveConstructible is satisfied if T is a reference type, or if it's an object type where an object of that type can be constructed from an rvalue of that type — in both direct-initialization and copy-initialization contexts — with the usual semantics 🫶.

🦋 more precisely, bestie 🦋

If T is an object type, then MoveConstructible<T> is satisfied only if given:

• rv, an rvalue of type T, and
• u2, a distinct object of type T equal to rv,

the following are true, periodt:

• After the definition T u = rv;, u is equal to u2;
• T{rv} is equal to u2; and
• If T is not const-qualified, then rv's resulting state (after the definition/expression is evaluated in either bullets above) is valid but unspecified; otherwise, it is unchanged.

⚠️ not me flagging the "valid but unspecified" part: that's a real vibe check from the standard, it doesn't promise you anything specific about rv afterward 💀 it's legal, it's just not telling you what's in there. And if T is const-qualified? Then it's unchanged, full stop 🙈

💅 See also 💅

• is_move_constructible — (C++11), class template ✨
• is_trivially_move_constructible — checks if a type can be constructed from an rvalue reference, (C++11), class template 🌈
• is_nothrow_move_constructible — (C++11), class template 💜

(iykyk — all three are the C++11 class-template girlies in the same club 🎀)

that's the whole page bestie, no crumbs left 🍓✨ this little icon was served up from http://cppreference.com, dated 2024.06.10, and its footer reads std::experi...nstructible(3) — slay, go move-construct something responsibly 💅👑