Stream: wasi

Topic: zbuild-std arg with wasip3

Ludea (Jan 12 2026 at 08:18):

Hi,
For now wasip3 crate doesn't support this arg with cargo.
Where can I track (repo / issue / PR) the work on this? (if work already started)

bjorn3 (Jan 12 2026 at 10:19):

-Zbuild-std should work for any target provided that you have the required linker and system libraries available. What is the error you get?

Ludea (Jan 12 2026 at 10:22):

https://github.com/rust-random/getrandom/actions/runs/20799036693/job/59739722173#step:6:99

bjorn3 (Jan 12 2026 at 11:10):

That is missing wasi-libc. For wasip2 the rustup component should ship with wasi-libc, but because we don't ship a wasip3 target, you need to manually point rustc to the clang in wasi-sdk with RUSTFLAGS="-Clinker=/path/to/wasi/clang": https://github.com/WebAssembly/wasi-sdk/releases/tag/wasi-sdk-29

Ludea (Jan 12 2026 at 14:14):

There is an accepted PR which start to add target https://github.com/WebAssembly/wasi-libc/pull/700.
So will wait until wasi-sdk bump with that work.

Alex Crichton (Jan 12 2026 at 15:32):

For the time being you can use clang with the wasm32-wasip2 target, for example /path/to/wasm32-wasip2-clang as the -Clinker. Otherwise though the wasip3 target isn't ready in Rust for prime time yet

Alex Crichton (Jan 12 2026 at 15:33):

I'll note that I do not plan on adding a wasip3 target to wasi-sdk just yet, leaving it test-only/build-from-source only in wasi-libc

Alex Crichton (Jan 12 2026 at 15:33):

We need to sort out ABI things before providing a precompiled binary

Ludea (Jan 12 2026 at 15:39):

I can wait, I don't need it for now.

Alex Crichton (Jan 12 2026 at 15:46):

If that's ok, that's what I'd recommend yeah. I think it's reasonable to add #[cfg]'d code for wasip3, to clarify, but testing it is going to be manual for now

Last updated: Jan 29 2026 at 13:25 UTC