# async-send-fd

A library for sending and receiving Unix file descriptors over async UnixStream connections.

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## Overview
The crate is a library for sending and receiving Unix file descriptors over [Tokio](https://crates.io/crates/tokio) or [Smol](https://crates.io/crates/smol) UnixStream connections.
You can send **RawFd** or **UnixStream** using provided interfaces.

See [test_smol_stream.rs](./tests/test_smol_stream.rs) or [test_tokio_stream.rs](./tests/test_tokio_stream.rs) for code examples.

## Creating **tokio::net::UnixStream** from **RawFd**
If you make a Tokio [UnixStream](https://docs.rs/tokio/latest/tokio/net/struct.UnixStream.html) from a raw file descriptor made by an OS call (e.g. [UnixStream::pair](https://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html)), you must make it [set_nonblocking(true)](https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixStream.html#method.set_nonblocking), otherwise receivers scheduler will block writing into the socket ⚠️

Smol [UnixStream](https://docs.rs/smol/2.0.0/smol/net/unix/struct.UnixStream.html) does it automatically if created using `UnixStream::from(Async::new(stream))`

## Transfering socket pair ownership
Note: the library closes Tokio stream if sent into another process.

## Features
- `tokio` - for Tokio support
- `smol` - for Smol support