Crate smol

A small and fast async runtime.

This crate simply re-exports other smaller async crates (see the source).

To use tokio-based libraries with smol, apply the async-compat adapter to futures and I/O types.

See the smol-macros crate if you want a no proc-macro, fast compiling, easy-to-use async main and/or multi-threaded Executor setup out of the box.

Examples

Connect to an HTTP website, make a GET request, and pipe the response to the standard output:

use smol::{io, net, prelude::*, Unblock};

fn main() -> io::Result<()> {
    smol::block_on(async {
        let mut stream = net::TcpStream::connect("example.com:80").await?;
        let req = b"GET / HTTP/1.1\r\nHost: example.com\r\nConnection: close\r\n\r\n";
        stream.write_all(req).await?;

        let mut stdout = Unblock::new(std::io::stdout());
        io::copy(stream, &mut stdout).await?;
        Ok(())
    })
}

There’s a lot more in the examples directory.

Modules

• channel
  An async multi-producer multi-consumer channel, where each message can be received by only one of all existing consumers.
• fs
  Async filesystem primitives.
• future
  Combinators for the Future trait.
• io
  Tools and combinators for I/O.
• lock
  Async synchronization primitives.
• net
  Async networking primitives for TCP/UDP/Unix communication.
• prelude
  Traits Future, Stream, AsyncRead, AsyncWrite, AsyncBufRead, AsyncSeek, and their extensions.
• process
  Async interface for working with processes.
• stream
  Combinators for the Stream trait.

Macros

• pin
  Pins a variable of type T on the stack and rebinds it as Pin<&mut T>.
• ready
  Unwraps Poll<T> or returns Pending.

Structs

• Async
  Async adapter for I/O types.
• Executor
  An async executor.
• LocalExecutor
  A thread-local executor.
• Task
  A spawned task.
• Timer
  A future or stream that emits timed events.
• Unblock
  Runs blocking I/O on a thread pool.

Functions

• block_on
  Blocks the current thread on a future, processing I/O events when idle.
• spawn
  Spawns a task onto the global executor (single-threaded by default).
• unblock
  Runs blocking code on a thread pool.