Module std::os::wasi

1.0.0 · source ·
Available on WASI only.
Expand description

Platform-specific extensions to std for the WebAssembly System Interface (WASI).

Provides access to platform-level information on WASI, and exposes WASI-specific functions that would otherwise be inappropriate as part of the core std library.

It exposes more ways to deal with platform-specific strings (OsStr, OsString), allows to set permissions more granularly, extract low-level file descriptors from files and sockets, and has platform-specific helpers for spawning processes.


use std::fs::File;
use std::os::wasi::prelude::*;

fn main() -> std::io::Result<()> {
    let f = File::create("foo.txt")?;
    let fd = f.as_raw_fd();

    // use fd with native WASI bindings



  • WASI-specific extensions to primitives in the std::ffi module
  • WASI-specific extensions to general I/O primitives.
  • A prelude for conveniently writing platform-specific code.
  • fsExperimental
    WASI-specific extensions to primitives in the std::fs module.
  • netExperimental
    WASI-specific networking functionality