| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/git/checkouts/tokio-377c595163f99a10/dfe252d/tokio/src/runtime/mod.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mod.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../tokio/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="doccomment">//! The Tokio runtime. |
| //! |
| //! Unlike other Rust programs, asynchronous applications require runtime |
| //! support. In particular, the following runtime services are necessary: |
| //! |
| //! * An **I/O event loop**, called the driver, which drives I/O resources and |
| //! dispatches I/O events to tasks that depend on them. |
| //! * A **scheduler** to execute [tasks] that use these I/O resources. |
| //! * A **timer** for scheduling work to run after a set period of time. |
| //! |
| //! Tokio's [`Runtime`] bundles all of these services as a single type, allowing |
| //! them to be started, shut down, and configured together. However, often it is |
| //! not required to configure a [`Runtime`] manually, and a user may just use the |
| //! [`tokio::main`] attribute macro, which creates a [`Runtime`] under the hood. |
| //! |
| //! # Usage |
| //! |
| //! When no fine tuning is required, the [`tokio::main`] attribute macro can be |
| //! used. |
| //! |
| //! ```no_run |
| //! use tokio::net::TcpListener; |
| //! use tokio::io::{AsyncReadExt, AsyncWriteExt}; |
| //! |
| //! #[tokio::main] |
| //! async fn main() -> Result<(), Box<dyn std::error::Error>> { |
| //! let listener = TcpListener::bind("127.0.0.1:8080").await?; |
| //! |
| //! loop { |
| //! let (mut socket, _) = listener.accept().await?; |
| //! |
| //! tokio::spawn(async move { |
| //! let mut buf = [0; 1024]; |
| //! |
| //! // In a loop, read data from the socket and write the data back. |
| //! loop { |
| //! let n = match socket.read(&mut buf).await { |
| //! // socket closed |
| //! Ok(n) if n == 0 => return, |
| //! Ok(n) => n, |
| //! Err(e) => { |
| //! println!("failed to read from socket; err = {:?}", e); |
| //! return; |
| //! } |
| //! }; |
| //! |
| //! // Write the data back |
| //! if let Err(e) = socket.write_all(&buf[0..n]).await { |
| //! println!("failed to write to socket; err = {:?}", e); |
| //! return; |
| //! } |
| //! } |
| //! }); |
| //! } |
| //! } |
| //! ``` |
| //! |
| //! From within the context of the runtime, additional tasks are spawned using |
| //! the [`tokio::spawn`] function. Futures spawned using this function will be |
| //! executed on the same thread pool used by the [`Runtime`]. |
| //! |
| //! A [`Runtime`] instance can also be used directly. |
| //! |
| //! ```no_run |
| //! use tokio::net::TcpListener; |
| //! use tokio::io::{AsyncReadExt, AsyncWriteExt}; |
| //! use tokio::runtime::Runtime; |
| //! |
| //! fn main() -> Result<(), Box<dyn std::error::Error>> { |
| //! // Create the runtime |
| //! let rt = Runtime::new()?; |
| //! |
| //! // Spawn the root task |
| //! rt.block_on(async { |
| //! let listener = TcpListener::bind("127.0.0.1:8080").await?; |
| //! |
| //! loop { |
| //! let (mut socket, _) = listener.accept().await?; |
| //! |
| //! tokio::spawn(async move { |
| //! let mut buf = [0; 1024]; |
| //! |
| //! // In a loop, read data from the socket and write the data back. |
| //! loop { |
| //! let n = match socket.read(&mut buf).await { |
| //! // socket closed |
| //! Ok(n) if n == 0 => return, |
| //! Ok(n) => n, |
| //! Err(e) => { |
| //! println!("failed to read from socket; err = {:?}", e); |
| //! return; |
| //! } |
| //! }; |
| //! |
| //! // Write the data back |
| //! if let Err(e) = socket.write_all(&buf[0..n]).await { |
| //! println!("failed to write to socket; err = {:?}", e); |
| //! return; |
| //! } |
| //! } |
| //! }); |
| //! } |
| //! }) |
| //! } |
| //! ``` |
| //! |
| //! ## Runtime Configurations |
| //! |
| //! Tokio provides multiple task scheduling strategies, suitable for different |
| //! applications. The [runtime builder] or `#[tokio::main]` attribute may be |
| //! used to select which scheduler to use. |
| //! |
| //! #### Multi-Thread Scheduler |
| //! |
| //! The multi-thread scheduler executes futures on a _thread pool_, using a |
| //! work-stealing strategy. By default, it will start a worker thread for each |
| //! CPU core available on the system. This tends to be the ideal configuration |
| //! for most applications. The multi-thread scheduler requires the `rt-multi-thread` |
| //! feature flag, and is selected by default: |
| //! ``` |
| //! use tokio::runtime; |
| //! |
| //! # fn main() -> Result<(), Box<dyn std::error::Error>> { |
| //! let threaded_rt = runtime::Runtime::new()?; |
| //! # Ok(()) } |
| //! ``` |
| //! |
| //! Most applications should use the multi-thread scheduler, except in some |
| //! niche use-cases, such as when running only a single thread is required. |
| //! |
| //! #### Current-Thread Scheduler |
| //! |
| //! The current-thread scheduler provides a _single-threaded_ future executor. |
| //! All tasks will be created and executed on the current thread. This requires |
| //! the `rt` feature flag. |
| //! ``` |
| //! use tokio::runtime; |
| //! |
| //! # fn main() -> Result<(), Box<dyn std::error::Error>> { |
| //! let rt = runtime::Builder::new_current_thread() |
| //! .build()?; |
| //! # Ok(()) } |
| //! ``` |
| //! |
| //! #### Resource drivers |
| //! |
| //! When configuring a runtime by hand, no resource drivers are enabled by |
| //! default. In this case, attempting to use networking types or time types will |
| //! fail. In order to enable these types, the resource drivers must be enabled. |
| //! This is done with [`Builder::enable_io`] and [`Builder::enable_time`]. As a |
| //! shorthand, [`Builder::enable_all`] enables both resource drivers. |
| //! |
| //! ## Lifetime of spawned threads |
| //! |
| //! The runtime may spawn threads depending on its configuration and usage. The |
| //! multi-thread scheduler spawns threads to schedule tasks and for `spawn_blocking` |
| //! calls. |
| //! |
| //! While the `Runtime` is active, threads may shutdown after periods of being |
| //! idle. Once `Runtime` is dropped, all runtime threads are forcibly shutdown. |
| //! Any tasks that have not yet completed will be dropped. |
| //! |
| //! [tasks]: crate::task |
| //! [`Runtime`]: Runtime |
| //! [`tokio::spawn`]: crate::spawn |
| //! [`tokio::main`]: ../attr.main.html |
| //! [runtime builder]: crate::runtime::Builder |
| //! [`Runtime::new`]: crate::runtime::Runtime::new |
| //! [`Builder::threaded_scheduler`]: crate::runtime::Builder::threaded_scheduler |
| //! [`Builder::enable_io`]: crate::runtime::Builder::enable_io |
| //! [`Builder::enable_time`]: crate::runtime::Builder::enable_time |
| //! [`Builder::enable_all`]: crate::runtime::Builder::enable_all |
| |
| </span><span class="comment">// At the top due to macros |
| </span><span class="attribute">#[cfg(test)] |
| #[cfg(not(tokio_wasm))] |
| #[macro_use] |
| </span><span class="kw">mod </span>tests; |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>context; |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>coop; |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>park; |
| |
| <span class="kw">mod </span>driver; |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>scheduler; |
| |
| <span class="macro">cfg_io_driver_impl! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>io; |
| } |
| |
| <span class="macro">cfg_process_driver! </span>{ |
| <span class="kw">mod </span>process; |
| } |
| |
| <span class="macro">cfg_time! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>time; |
| } |
| |
| <span class="macro">cfg_signal_internal_and_unix! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>signal; |
| } |
| |
| <span class="macro">cfg_rt! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>task; |
| |
| <span class="kw">mod </span>config; |
| <span class="kw">use </span>config::Config; |
| |
| <span class="kw">mod </span>blocking; |
| <span class="attribute">#[cfg_attr(tokio_wasi, allow(unused_imports))] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>blocking::spawn_blocking; |
| |
| <span class="macro">cfg_trace! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>blocking::Mandatory; |
| } |
| |
| <span class="macro">cfg_fs! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>blocking::spawn_mandatory_blocking; |
| } |
| |
| <span class="kw">mod </span>builder; |
| <span class="kw">pub use </span><span class="self">self</span>::builder::Builder; |
| <span class="macro">cfg_unstable! </span>{ |
| <span class="kw">pub use </span><span class="self">self</span>::builder::UnhandledPanic; |
| <span class="kw">pub use </span><span class="kw">crate</span>::util::rand::RngSeed; |
| } |
| |
| <span class="kw">mod </span>defer; |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>defer::Defer; |
| |
| <span class="kw">mod </span>handle; |
| <span class="kw">pub use </span>handle::{EnterGuard, Handle, TryCurrentError}; |
| |
| <span class="kw">mod </span>runtime; |
| <span class="kw">pub use </span>runtime::{Runtime, RuntimeFlavor}; |
| |
| <span class="kw">mod </span>thread_id; |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>thread_id::ThreadId; |
| |
| <span class="macro">cfg_metrics! </span>{ |
| <span class="kw">mod </span>metrics; |
| <span class="kw">pub use </span>metrics::RuntimeMetrics; |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>metrics::{MetricsBatch, SchedulerMetrics, WorkerMetrics}; |
| |
| <span class="macro">cfg_net! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>metrics::IoDriverMetrics; |
| } |
| } |
| |
| <span class="macro">cfg_not_metrics! </span>{ |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>metrics; |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>metrics::{SchedulerMetrics, WorkerMetrics, MetricsBatch}; |
| } |
| |
| <span class="doccomment">/// After thread starts / before thread stops |
| </span><span class="kw">type </span>Callback = std::sync::Arc<<span class="kw">dyn </span>Fn() + Send + Sync>; |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
