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# errno [](https://github.com/lambda-fairy/rust-errno/actions/workflows/main.yml) [](https://crates.io/crates/errno)
Cross-platform interface to the [`errno`][errno] variable. Works on Rust 1.56 or newer.
## Dependency
Add to your `Cargo.toml`:
```toml
[dependencies]
errno = "*"
```
## Comparison with `std::io::Error`
The standard library provides [`Error::last_os_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
## Examples
```rust
extern crate errno;
use errno::{Errno, errno, set_errno};
// Get the current value of errno
let e = errno();
// Set the current value of errno
set_errno(e);
// Extract the error code as an i32
let code = e.0;
// Display a human-friendly error message
println!("Error {}: {}", code, e);
```
## `#![no_std]`
Enable `#![no_std]` support by disabling the default `std` feature:
```toml
[dependencies]
errno = { version = "*", default-features = false }
```
The `Error` impl will be unavailable.