Tag: no-std

When working with Rust + Webassembly, you might want to use some crates in your project. Not all crates work out of the box with Webassembly yet, especially those that rely on System Libraries, File I/O, Networking, etc. With proposals such as WASI or WebAssembly Interface Types, these might work eventually but it isn’t the case yet.

The Rust Wasm book suggests: A good rule of thumb is that if a crate supports embedded and #![no_std] usage, it probably also supports WebAssembly.

I noticed that I quite enjoy writing libraries that support no_std environments, even though I myself don't even work on embedded. Its just very fun to try and get as many features done without ever allocating, purely from a challenge point of view.

There is also some benefits one can hope for, the two big ones being usability in more cases, like embedded, and better performance due to less memory management overhead, possibly less indirection and therefore more compiler insight.

When creating a Rust crate that aims to be no_std compatible, it can happen that you accidentally break that promise without noticing. To demonstrate this, let's create an example project.