errno 0.3.8

Cross-platform interface to the `errno` variable.

errno CI Cargo

Cross-platform interface to the errno variable. Works on Rust 1.56 or newer.

Documentation is available at


Add to your Cargo.toml:

errno = "*"

Comparison with std::io::Error

The standard library provides Error::last_os_error which fetches errno in the same way.

This crate provides these extra features:

  • No heap allocations
  • Optional #![no_std] support
  • A set_errno function


extern crate errno;
use errno::{Errno, errno, set_errno};

// Get the current value of errno
let e = errno();

// Set the current value of errno

// Extract the error code as an i32
let code = e.0;

// Display a human-friendly error message
println!("Error {}: {}", code, e);


Enable #![no_std] support by disabling the default std feature:

errno = { version = "*", default-features = false }

The Error impl will be unavailable.