| # errno [](https://github.com/lambda-fairy/rust-errno/actions/workflows/main.yml) [](https://crates.io/crates/errno) |
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| Cross-platform interface to the [`errno`][errno] variable. Works on Rust 1.56 or newer. |
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| Documentation is available at <https://docs.rs/errno>. |
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| [errno]: https://en.wikipedia.org/wiki/Errno.h |
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| ## Dependency |
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| Add to your `Cargo.toml`: |
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| ```toml |
| [dependencies] |
| errno = "*" |
| ``` |
| |
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| ## Comparison with `std::io::Error` |
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| The standard library provides [`Error::last_os_error`][last_os_error] which fetches `errno` in the same way. |
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| This crate provides these extra features: |
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| - No heap allocations |
| - Optional `#![no_std]` support |
| - A `set_errno` function |
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| [last_os_error]: https://doc.rust-lang.org/std/io/struct.Error.html#method.last_os_error |
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| ## Examples |
| |
| ```rust |
| extern crate errno; |
| use errno::{Errno, errno, set_errno}; |
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| // Get the current value of errno |
| let e = errno(); |
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| // Set the current value of errno |
| set_errno(e); |
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| // Extract the error code as an i32 |
| let code = e.0; |
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| // Display a human-friendly error message |
| println!("Error {}: {}", code, e); |
| ``` |
| |
| |
| ## `#![no_std]` |
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| Enable `#![no_std]` support by disabling the default `std` feature: |
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| ```toml |
| [dependencies] |
| errno = { version = "*", default-features = false } |
| ``` |
| |
| The `Error` impl will be unavailable. |
