Rust has explicit subsets of its standard library: * core, whose only dependencies are six symbols (memcpy, memcmp, memset, strlen, rust_begin_panic, and rust_

Rust has explicit subsets of its standard library: * core, whose only dependencies are six symbols (memcpy, memcmp, memset, strlen, rust_begin_panic, and rust_eh_personality) * alloc, which layers on top of core, and adds the ability to allocate memory * std, which includes all of the operating system specific things But most importantly, you can declare that your code doesn't require std and alloc with an annotation, and there's a way to tag these crates in the package manager as well. Additionally, cargo has a "features" feature, so you can say "please give me the no_std version of the library" and get what fits within your needs. My team at work is working purely in the 'core' subset, and we're able to easily find and evaluate open source projects that will work for us, because of this. Oh, I should also mention: while Rust doesn't have exceptions, there's also a way to compile your program so that panics abort instead of unwind the stack, similar to -fno-exceptions being passed when compiling C++ code. There is also a setting you can include so that, if, for some reason, you require the unwinding semantics, if someone tries to build a project with abort semantics and your program, it will not allow it and let you know why. I don't think I've ever seen this annotation on a package in the wild, because since they're not used in the regular course of programming in Rust, virtually every open source library does not use them for important semantics and so therefore works with either setting.