Crate futures

Abstractions for asynchronous programming.

This crate provides a number of core abstractions for writing asynchronous code:

• Futures (sometimes called promises), which represent a single asychronous computation that may result in a final value or an error.

• Streams, which represent a series of values or errors produced asynchronously.

• Sinks, which support asynchronous writing of data.

• Executors, which are responsible for running asynchronous tasks.

The crate also contains abstractions for asynchronous I/O and cross-task communication.

Underlying all of this is the task system, which is a form of lightweight threading. Large asynchronous computations are built up using futures, streams and sinks, and then spawned as independent tasks that are run to completion, but do not block the thread running them.

Modules

• channel
  Cross-task communication.
• executor
  Task execution.
• future
  Asynchronous values.
• io
  Asynchronous I/O.
• never
  This module contains the Never type.
• prelude
  A “prelude” for crates using the futures crate.
• sink
  Asynchronous sinks.
• stream
  Asynchronous streams.
• task
  Tools for working with tasks.

Macros

• task_local
  A macro to create a static of type LocalKey.
• try_ready
  A macro for extracting the successful type of a Poll<T, E>.

Enums

• Async
  Indicates whether a value is available, or if the current task has been scheduled for later wake-up instead.
• Never
  A type with no possible values.

Traits

• Future
  A future represents an asychronous computation that may fail.
• FutureExt
  An extension trait for Futures that provides a variety of convenient combinator functions.
• IntoFuture
  Types that can be converted into a future.
• Sink
  A Sink is a value into which other values can be sent, asynchronously.
• SinkExt
  An extension trait for Sinks that provides a variety of convenient combinator functions.
• Stream
  A stream of values produced asynchronously.
• StreamExt
  An extension trait for Streams that provides a variety of convenient combinator functions.

Type Aliases

• Poll
  A convenience wrapper for Result<Async<T>, E>.