| <!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="Waits until `duration` has elapsed."><meta name="keywords" content="rust, rustlang, rust-lang, sleep"><title>sleep in tokio::time - 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="sidebar-items.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 fn"><!--[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="../../tokio/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="../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><div class="sidebar-elems"><h2><a href="index.html">In tokio::time</a></h2></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">Function <a href="../index.html">tokio</a>::<wbr><a href="index.html">time</a>::<wbr><a class="fn" href="#">sleep</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/tokio/time/sleep.rs.html#125-132">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust fn"><code>pub fn sleep(duration: Duration) -> <a class="struct" href="struct.Sleep.html" title="struct tokio::time::Sleep">Sleep</a><span class="notable-traits"><span class="notable-traits-tooltip">ⓘ<span class="notable-traits-tooltiptext"><span class="docblock"><span class="notable">Notable traits for <a class="struct" href="struct.Sleep.html" title="struct tokio::time::Sleep">Sleep</a></span><code class="content"><span class="where fmt-newline">impl Future for <a class="struct" href="struct.Sleep.html" title="struct tokio::time::Sleep">Sleep</a></span><span class="where fmt-newline"> type <a class="associatedtype">Output</a> = ();</span></code></span></span></span></span></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Waits until <code>duration</code> has elapsed.</p> |
| <p>Equivalent to <code>sleep_until(Instant::now() + duration)</code>. An asynchronous |
| analog to <code>std::thread::sleep</code>.</p> |
| <p>No work is performed while awaiting on the sleep future to complete. <code>Sleep</code> |
| operates at millisecond granularity and should not be used for tasks that |
| require high-resolution timers. The implementation is platform specific, |
| and some platforms (specifically Windows) will provide timers with a |
| larger resolution than 1 ms.</p> |
| <p>To run something regularly on a schedule, see <a href="fn.interval.html"><code>interval</code></a>.</p> |
| <p>The maximum duration for a sleep is 68719476734 milliseconds (approximately 2.2 years).</p> |
| <h2 id="cancellation"><a href="#cancellation">Cancellation</a></h2> |
| <p>Canceling a sleep instance is done by dropping the returned future. No additional |
| cleanup work is required.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <p>Wait 100ms and print “100 ms have elapsed”.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::time::{sleep, Duration}; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| sleep(Duration::from_millis(<span class="number">100</span>)).<span class="kw">await</span>; |
| <span class="macro">println!</span>(<span class="string">"100 ms have elapsed"</span>); |
| }</code></pre></div> |
| <p>See the documentation for the <a href="struct.Sleep.html"><code>Sleep</code></a> type for more examples.</p> |
| <h2 id="panics"><a href="#panics">Panics</a></h2> |
| <p>This function panics if there is no current timer set.</p> |
| <p>It can be triggered when <a href="../runtime/struct.Builder.html#method.enable_time"><code>Builder::enable_time</code></a> or |
| <a href="../runtime/struct.Builder.html#method.enable_all"><code>Builder::enable_all</code></a> are not included in the builder.</p> |
| <p>It can also panic whenever a timer is created outside of a |
| Tokio runtime. That is why <code>rt.block_on(sleep(...))</code> will panic, |
| since the function is executed outside of the runtime. |
| Whereas <code>rt.block_on(async {sleep(...).await})</code> doesn’t panic. |
| And this is because wrapping the function on an async makes it lazy, |
| and so gets executed inside the runtime successfully without |
| panicking.</p> |
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