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

**URL:** <https://forum.devtalk.com/t/rust-c-abi-changes-for-wasm32-unknown-unknown/193808>\
**Category:** Backend Official News\
**Tags:** newsbot, rust, wasm, official-news\
**Created:** [4 April 2025 14:21 UTC](https://forum.devtalk.com/t/rust-c-abi-changes-for-wasm32-unknown-unknown/193808 "2025-04-04T14:21:13Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![NewsBot](https://forum.devtalk.com/user_avatar/forum.devtalk.com/newsbot/32/1114_2.png) [@NewsBot](https://forum.devtalk.com/u/NewsBot)\
**Post date:** [4 April 2025 14:21 UTC](https://forum.devtalk.com/t/rust-c-abi-changes-for-wasm32-unknown-unknown/193808/1 "2025-04-04T14:21:13Z")

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A new [Rust](https://devtalk.com/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](https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md) and it additionally [leaks internal compiler implementation details](https://github.com/rust-lang/rust/issues/115666) of both the Rust compiler and LLVM. This will change in a future version of the Rust compiler and the [official C ABI](https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md) 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?"](#am-i-affected) as well.
> 
> ## [https://blog.rust-lang.org/2025/04/04/c-abi-changes-for-wasm32-unknown-unknown.html](#history-of-wasm32-unknown-unknowns-c-abi)