| <!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="Built-in executors and related tools."><meta name="keywords" content="rust, rustlang, rust-lang, executor"><title>futures::executor - Rust</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="../../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 mod"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../../futures/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../futures/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">Module executor</a></h2><div class="sidebar-elems"><section><ul class="block"><li><a href="#structs">Structs</a></li><li><a href="#functions">Functions</a></li></ul></section></div></nav><main><div class="width-limiter"><nav class="sub"><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="main-heading"><h1 class="fqn">Module <a href="../index.html">futures</a>::<wbr><a class="mod" href="#">executor</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../../src/futures/lib.rs.html#156">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Built-in executors and related tools.</p> |
| <p>All asynchronous computation occurs within an executor, which is |
| capable of spawning futures as tasks. This module provides several |
| built-in executors, as well as tools for building your own.</p> |
| <p>This module is only available when the <code>executor</code> feature of this |
| library is activated.</p> |
| <h2 id="using-a-thread-pool-mn-task-scheduling"><a href="#using-a-thread-pool-mn-task-scheduling">Using a thread pool (M:N task scheduling)</a></h2> |
| <p>Most of the time tasks should be executed on a <a href="ThreadPool">thread pool</a>. |
| A small set of worker threads can handle a very large set of spawned tasks |
| (which are much lighter weight than threads). Tasks spawned onto the pool |
| with the <a href="ThreadPool::spawn_ok"><code>spawn_ok</code></a> function will run ambiently on |
| the created threads.</p> |
| <h2 id="spawning-additional-tasks"><a href="#spawning-additional-tasks">Spawning additional tasks</a></h2> |
| <p>Tasks can be spawned onto a spawner by calling its <a href="https://docs.rs/futures/0.3/futures/task/trait.Spawn.html#tymethod.spawn_obj"><code>spawn_obj</code></a> method |
| directly. In the case of <code>!Send</code> futures, <a href="https://docs.rs/futures/0.3/futures/task/trait.LocalSpawn.html#tymethod.spawn_local_obj"><code>spawn_local_obj</code></a> can be used |
| instead.</p> |
| <h2 id="single-threaded-execution"><a href="#single-threaded-execution">Single-threaded execution</a></h2> |
| <p>In addition to thread pools, it’s possible to run a task (and the tasks |
| it spawns) entirely within a single thread via the <a href="struct.LocalPool.html" title="LocalPool"><code>LocalPool</code></a> executor. |
| Aside from cutting down on synchronization costs, this executor also makes |
| it possible to spawn non-<code>Send</code> tasks, via <a href="https://docs.rs/futures/0.3/futures/task/trait.LocalSpawn.html#tymethod.spawn_local_obj"><code>spawn_local_obj</code></a>. The |
| <a href="struct.LocalPool.html" title="LocalPool"><code>LocalPool</code></a> is best suited for running I/O-bound tasks that do relatively |
| little work between I/O operations.</p> |
| <p>There is also a convenience function <a href="fn.block_on.html" title="block_on"><code>block_on</code></a> for simply running a |
| future to completion on the current thread.</p> |
| </div></details><h2 id="structs" class="small-section-header"><a href="#structs">Structs</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.BlockingStream.html" title="futures::executor::BlockingStream struct">BlockingStream</a></div><div class="item-right docblock-short">An iterator which blocks on values from a stream until they become available.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.Enter.html" title="futures::executor::Enter struct">Enter</a></div><div class="item-right docblock-short">Represents an executor context.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.EnterError.html" title="futures::executor::EnterError struct">EnterError</a></div><div class="item-right docblock-short">An error returned by <code>enter</code> if an execution scope has already been |
| entered.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.LocalPool.html" title="futures::executor::LocalPool struct">LocalPool</a></div><div class="item-right docblock-short">A single-threaded task pool for polling futures to completion.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.LocalSpawner.html" title="futures::executor::LocalSpawner struct">LocalSpawner</a></div><div class="item-right docblock-short">A handle to a <a href="struct.LocalPool.html"><code>LocalPool</code></a> that implements |
| <a href="../task/trait.Spawn.html"><code>Spawn</code></a>.</div></div></div><h2 id="functions" class="small-section-header"><a href="#functions">Functions</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.block_on.html" title="futures::executor::block_on fn">block_on</a></div><div class="item-right docblock-short">Run a future to completion on the current thread.</div></div><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.block_on_stream.html" title="futures::executor::block_on_stream fn">block_on_stream</a></div><div class="item-right docblock-short">Turn a stream into a blocking iterator.</div></div><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.enter.html" title="futures::executor::enter fn">enter</a></div><div class="item-right docblock-short">Marks the current thread as being within the dynamic extent of an |
| executor.</div></div></div></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="futures" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
