C/C++ standard library doesn't work in that environment anyway---you typically need a freestanding mode. Rust equvialent is `#[no_std]` which works well for popular boards.
To be technical, Rust deliberately splits out three elements: core (which is necessary for the Rust language and is always provided) alloc (which needs a heap allocator, not applicable if you don't have or don't want one) and then std (which expects an operating system, with features like files and sockets and threads and knowing what the time is)
C++ just labels a few specific features as available in a "freestanding" C++ standard library if you have one (on an embedded platform presumably you do).
This makes it very easy to know what you're getting in Rust's stdlib in #[no_std] because it's all of core, so e.g.
At first glance those are identical, but no, std is re-exporting every feature core had, but it also gains features, for example the stable sort function family only exist in std because they're using a temporary allocation whereas the unstable (ie equivalent items may be re-ordered) sort provided even in core doesn't do that.
Figuring out what you get in your stdlib with C++ often comes down to suck it and see.
