Rust: C ABI Changes for `wasm32-unknown-unknown`

[NewsBot]

A new Rust blog post/announcement has been posted!

The extern "C" ABI for the wasm32-unknown-unknown target has been using a non-standard definition since the inception of the target in that it does not implement the official C ABI of WebAssembly and it additionally leaks internal compiler implementation details of both the Rust compiler and LLVM. This will change in a future version of the Rust compiler and the official C ABI will be used instead.

This post details some history behind this change and the rationale for why it's being announced here, but you can skip straight to "Am I affected?" as well.

https://blog.rust-lang.org/2025/04/04/c-abi-changes-for-wasm32-unknown-unknown.html