| <!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="A set of tasks which are executed on the same thread."><meta name="keywords" content="rust, rustlang, rust-lang, LocalSet"><title>LocalSet in tokio::task - 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 struct"><!--[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><h2 class="location"><a href="#">LocalSet</a></h2><div class="sidebar-elems"><section><h3><a href="#implementations">Methods</a></h3><ul class="block"><li><a href="#method.block_on">block_on</a></li><li><a href="#method.enter">enter</a></li><li><a href="#method.new">new</a></li><li><a href="#method.run_until">run_until</a></li><li><a href="#method.spawn_local">spawn_local</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block"><li><a href="#impl-Debug-for-LocalSet">Debug</a></li><li><a href="#impl-Default-for-LocalSet">Default</a></li><li><a href="#impl-Drop-for-LocalSet">Drop</a></li><li><a href="#impl-Future-for-LocalSet">Future</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block"><li><a href="#impl-RefUnwindSafe-for-LocalSet">!RefUnwindSafe</a></li><li><a href="#impl-Send-for-LocalSet">!Send</a></li><li><a href="#impl-Sync-for-LocalSet">!Sync</a></li><li><a href="#impl-Unpin-for-LocalSet">Unpin</a></li><li><a href="#impl-UnwindSafe-for-LocalSet">!UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block"><li><a href="#impl-Any-for-LocalSet">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-LocalSet">Borrow<T></a></li><li><a href="#impl-BorrowMut%3CT%3E-for-LocalSet">BorrowMut<T></a></li><li><a href="#impl-From%3CT%3E-for-LocalSet">From<T></a></li><li><a href="#impl-Into%3CU%3E-for-LocalSet">Into<U></a></li><li><a href="#impl-IntoFuture-for-LocalSet">IntoFuture</a></li><li><a href="#impl-TryFrom%3CU%3E-for-LocalSet">TryFrom<U></a></li><li><a href="#impl-TryInto%3CU%3E-for-LocalSet">TryInto<U></a></li></ul></section><h2><a href="index.html">In tokio::task</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">Struct <a href="../index.html">tokio</a>::<wbr><a href="index.html">task</a>::<wbr><a class="struct" href="#">LocalSet</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/task/local.rs.html#216-225">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 struct"><code>pub struct LocalSet { /* private fields */ }</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>A set of tasks which are executed on the same thread.</p> |
| <p>In some cases, it is necessary to run one or more futures that do not |
| implement <a href="trait@std::marker::Send"><code>Send</code></a> and thus are unsafe to send between threads. In these |
| cases, a <a href="struct.LocalSet.html">local task set</a> may be used to schedule one or more <code>!Send</code> |
| futures to run together on the same thread.</p> |
| <p>For example, the following code will not compile:</p> |
| |
| <div class="example-wrap compile_fail"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::rc::Rc; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="comment">// `Rc` does not implement `Send`, and thus may not be sent between |
| // threads safely. |
| </span><span class="kw">let </span>unsend_data = Rc::new(<span class="string">"my unsend data..."</span>); |
| |
| <span class="kw">let </span>unsend_data = unsend_data.clone(); |
| <span class="comment">// Because the `async` block here moves `unsend_data`, the future is `!Send`. |
| // Since `tokio::spawn` requires the spawned future to implement `Send`, this |
| // will not compile. |
| </span>tokio::spawn(<span class="kw">async move </span>{ |
| <span class="macro">println!</span>(<span class="string">"{}"</span>, unsend_data); |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>.unwrap(); |
| }</code></pre></div> |
| <h2 id="use-with-run_until"><a href="#use-with-run_until">Use with <code>run_until</code></a></h2> |
| <p>To spawn <code>!Send</code> futures, we can use a local task set to schedule them |
| on the thread calling <a href="../runtime/struct.Runtime.html#method.block_on"><code>Runtime::block_on</code></a>. When running inside of the |
| local task set, we can use <a href="fn.spawn_local.html"><code>task::spawn_local</code></a>, which can spawn |
| <code>!Send</code> futures. For example:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::rc::Rc; |
| <span class="kw">use </span>tokio::task; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>unsend_data = Rc::new(<span class="string">"my unsend data..."</span>); |
| |
| <span class="comment">// Construct a local task set that can run `!Send` futures. |
| </span><span class="kw">let </span>local = task::LocalSet::new(); |
| |
| <span class="comment">// Run the local task set. |
| </span>local.run_until(<span class="kw">async move </span>{ |
| <span class="kw">let </span>unsend_data = unsend_data.clone(); |
| <span class="comment">// `spawn_local` ensures that the future is spawned on the local |
| // task set. |
| </span>task::spawn_local(<span class="kw">async move </span>{ |
| <span class="macro">println!</span>(<span class="string">"{}"</span>, unsend_data); |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>.unwrap(); |
| }).<span class="kw">await</span>; |
| }</code></pre></div> |
| <p><strong>Note:</strong> The <code>run_until</code> method can only be used in <code>#[tokio::main]</code>, |
| <code>#[tokio::test]</code> or directly inside a call to <a href="../runtime/struct.Runtime.html#method.block_on"><code>Runtime::block_on</code></a>. It |
| cannot be used inside a task spawned with <code>tokio::spawn</code>.</p> |
| <h3 id="awaiting-a-localset"><a href="#awaiting-a-localset">Awaiting a <code>LocalSet</code></a></h3> |
| <p>Additionally, a <code>LocalSet</code> itself implements <code>Future</code>, completing when |
| <em>all</em> tasks spawned on the <code>LocalSet</code> complete. This can be used to run |
| several futures on a <code>LocalSet</code> and drive the whole set until they |
| complete. For example,</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::{task, time}; |
| <span class="kw">use </span>std::rc::Rc; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>unsend_data = Rc::new(<span class="string">"world"</span>); |
| <span class="kw">let </span>local = task::LocalSet::new(); |
| |
| <span class="kw">let </span>unsend_data2 = unsend_data.clone(); |
| local.spawn_local(<span class="kw">async move </span>{ |
| <span class="comment">// ... |
| </span><span class="macro">println!</span>(<span class="string">"hello {}"</span>, unsend_data2) |
| }); |
| |
| local.spawn_local(<span class="kw">async move </span>{ |
| time::sleep(time::Duration::from_millis(<span class="number">100</span>)).<span class="kw">await</span>; |
| <span class="macro">println!</span>(<span class="string">"goodbye {}"</span>, unsend_data) |
| }); |
| |
| <span class="comment">// ... |
| |
| </span>local.<span class="kw">await</span>; |
| }</code></pre></div> |
| <p><strong>Note:</strong> Awaiting a <code>LocalSet</code> can only be done inside |
| <code>#[tokio::main]</code>, <code>#[tokio::test]</code> or directly inside a call to |
| <a href="../runtime/struct.Runtime.html#method.block_on"><code>Runtime::block_on</code></a>. It cannot be used inside a task spawned with |
| <code>tokio::spawn</code>.</p> |
| <h3 id="use-inside-tokiospawn"><a href="#use-inside-tokiospawn">Use inside <code>tokio::spawn</code></a></h3> |
| <p>The two methods mentioned above cannot be used inside <code>tokio::spawn</code>, so |
| to spawn <code>!Send</code> futures from inside <code>tokio::spawn</code>, we need to do |
| something else. The solution is to create the <code>LocalSet</code> somewhere else, |
| and communicate with it using an <a href="../sync/mpsc/index.html"><code>mpsc</code></a> channel.</p> |
| <p>The following example puts the <code>LocalSet</code> inside a new thread.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::runtime::Builder; |
| <span class="kw">use </span>tokio::sync::{mpsc, oneshot}; |
| <span class="kw">use </span>tokio::task::LocalSet; |
| |
| <span class="comment">// This struct describes the task you want to spawn. Here we include |
| // some simple examples. The oneshot channel allows sending a response |
| // to the spawner. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">enum </span>Task { |
| PrintNumber(u32), |
| AddOne(u32, oneshot::Sender<u32>), |
| } |
| |
| <span class="attribute">#[derive(Clone)] |
| </span><span class="kw">struct </span>LocalSpawner { |
| send: mpsc::UnboundedSender<Task>, |
| } |
| |
| <span class="kw">impl </span>LocalSpawner { |
| <span class="kw">pub fn </span>new() -> <span class="self">Self </span>{ |
| <span class="kw">let </span>(send, <span class="kw-2">mut </span>recv) = mpsc::unbounded_channel(); |
| |
| <span class="kw">let </span>rt = Builder::new_current_thread() |
| .enable_all() |
| .build() |
| .unwrap(); |
| |
| std::thread::spawn(<span class="kw">move </span>|| { |
| <span class="kw">let </span>local = LocalSet::new(); |
| |
| local.spawn_local(<span class="kw">async move </span>{ |
| <span class="kw">while let </span><span class="prelude-val">Some</span>(new_task) = recv.recv().<span class="kw">await </span>{ |
| tokio::task::spawn_local(run_task(new_task)); |
| } |
| <span class="comment">// If the while loop returns, then all the LocalSpawner |
| // objects have been dropped. |
| </span>}); |
| |
| <span class="comment">// This will return once all senders are dropped and all |
| // spawned tasks have returned. |
| </span>rt.block_on(local); |
| }); |
| |
| <span class="self">Self </span>{ |
| send, |
| } |
| } |
| |
| <span class="kw">pub fn </span>spawn(<span class="kw-2">&</span><span class="self">self</span>, task: Task) { |
| <span class="self">self</span>.send.send(task).expect(<span class="string">"Thread with LocalSet has shut down."</span>); |
| } |
| } |
| |
| <span class="comment">// This task may do !Send stuff. We use printing a number as an example, |
| // but it could be anything. |
| // |
| // The Task struct is an enum to support spawning many different kinds |
| // of operations. |
| </span><span class="kw">async fn </span>run_task(task: Task) { |
| <span class="kw">match </span>task { |
| Task::PrintNumber(n) => { |
| <span class="macro">println!</span>(<span class="string">"{}"</span>, n); |
| }, |
| Task::AddOne(n, response) => { |
| <span class="comment">// We ignore failures to send the response. |
| </span><span class="kw">let _ </span>= response.send(n + <span class="number">1</span>); |
| }, |
| } |
| } |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>spawner = LocalSpawner::new(); |
| |
| <span class="kw">let </span>(send, response) = oneshot::channel(); |
| spawner.spawn(Task::AddOne(<span class="number">10</span>, send)); |
| <span class="kw">let </span>eleven = response.<span class="kw">await</span>.unwrap(); |
| <span class="macro">assert_eq!</span>(eleven, <span class="number">11</span>); |
| }</code></pre></div> |
| </div></details><h2 id="implementations" class="small-section-header">Implementations<a href="#implementations" class="anchor"></a></h2><div id="implementations-list"><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-LocalSet" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#377-719">source</a><a href="#impl-LocalSet" class="anchor"></a><h3 class="code-header">impl <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.new" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#379-400">source</a><h4 class="code-header">pub fn <a href="#method.new" class="fnname">new</a>() -> <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</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.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></span><code class="content"><span class="where fmt-newline">impl Future for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></span><span class="where fmt-newline"> type <a class="associatedtype">Output</a> = ();</span></code></span></span></span></span></h4></section></summary><div class="docblock"><p>Returns a new local task set.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.enter" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#408-413">source</a><h4 class="code-header">pub fn <a href="#method.enter" class="fnname">enter</a>(&self) -> <a class="struct" href="struct.LocalEnterGuard.html" title="struct tokio::task::LocalEnterGuard">LocalEnterGuard</a></h4></section></summary><div class="docblock"><p>Enters the context of this <code>LocalSet</code>.</p> |
| <p>The <a href="fn.spawn_local.html"><code>spawn_local</code></a> method will spawn tasks on the <code>LocalSet</code> whose |
| context you are inside.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.spawn_local" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#458-464">source</a><h4 class="code-header">pub fn <a href="#method.spawn_local" class="fnname">spawn_local</a><F>(&self, future: F) -> <a class="struct" href="struct.JoinHandle.html" title="struct tokio::task::JoinHandle">JoinHandle</a><F::Output><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.JoinHandle.html" title="struct tokio::task::JoinHandle">JoinHandle</a><T></span><code class="content"><span class="where fmt-newline">impl<T> Future for <a class="struct" href="struct.JoinHandle.html" title="struct tokio::task::JoinHandle">JoinHandle</a><T></span><span class="where fmt-newline"> type <a class="associatedtype">Output</a> = Result<T, <a class="struct" href="struct.JoinError.html" title="struct tokio::task::JoinError">JoinError</a>>;</span></code></span></span></span></span><span class="where fmt-newline">where<br> F: Future + 'static,<br> F::Output: 'static,</span></h4></section></summary><div class="docblock"><p>Spawns a <code>!Send</code> task onto the local task set.</p> |
| <p>This task is guaranteed to be run on the current thread.</p> |
| <p>Unlike the free function <a href="fn.spawn_local.html"><code>spawn_local</code></a>, this method may be used to |
| spawn local tasks when the <code>LocalSet</code> is <em>not</em> running. You do not have |
| to <code>.await</code> the returned <code>JoinHandle</code> to make the provided future start |
| execution. It will start running immediately whenever the <code>LocalSet</code> is |
| next started.</p> |
| <h5 id="examples"><a href="#examples">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::task; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>local = task::LocalSet::new(); |
| |
| <span class="comment">// Spawn a future on the local set. This future will be run when |
| // we call `run_until` to drive the task set. |
| </span>local.spawn_local(<span class="kw">async </span>{ |
| <span class="comment">// ... |
| </span>}); |
| |
| <span class="comment">// Run the local task set. |
| </span>local.run_until(<span class="kw">async move </span>{ |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>; |
| |
| <span class="comment">// When `run` finishes, we can spawn _more_ futures, which will |
| // run in subsequent calls to `run_until`. |
| </span>local.spawn_local(<span class="kw">async </span>{ |
| <span class="comment">// ... |
| </span>}); |
| |
| local.run_until(<span class="kw">async move </span>{ |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>; |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.block_on" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#531-536">source</a><h4 class="code-header">pub fn <a href="#method.block_on" class="fnname">block_on</a><F>(&self, rt: &<a class="struct" href="../runtime/struct.Runtime.html" title="struct tokio::runtime::Runtime">Runtime</a>, future: F) -> F::Output<span class="where fmt-newline">where<br> F: Future,</span></h4></section></summary><div class="docblock"><p>Runs a future to completion on the provided runtime, driving any local |
| futures spawned on this task set on the current thread.</p> |
| <p>This runs the given future on the runtime, blocking until it is |
| complete, and yielding its resolved result. Any tasks or timers which |
| the future spawns internally will be executed on the runtime. The future |
| may also call <a href="fn.spawn_local.html"><code>spawn_local</code></a> to spawn_local additional local futures on the |
| current thread.</p> |
| <p>This method should not be called from an asynchronous context.</p> |
| <h5 id="panics"><a href="#panics">Panics</a></h5> |
| <p>This function panics if the executor is at capacity, if the provided |
| future panics, or if called within an asynchronous execution context.</p> |
| <h5 id="notes"><a href="#notes">Notes</a></h5> |
| <p>Since this function internally calls <a href="../runtime/struct.Runtime.html#method.block_on"><code>Runtime::block_on</code></a>, and drives |
| futures in the local task set inside that call to <code>block_on</code>, the local |
| futures may not use <a href="fn.block_in_place.html">in-place blocking</a>. If a blocking call needs to be |
| issued from a local task, the <a href="fn.spawn_blocking.html"><code>spawn_blocking</code></a> API may be used instead.</p> |
| <p>For example, this will panic:</p> |
| |
| <div class="example-wrap should_panic"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::runtime::Runtime; |
| <span class="kw">use </span>tokio::task; |
| |
| <span class="kw">let </span>rt = Runtime::new().unwrap(); |
| <span class="kw">let </span>local = task::LocalSet::new(); |
| local.block_on(<span class="kw-2">&</span>rt, <span class="kw">async </span>{ |
| <span class="kw">let </span>join = task::spawn_local(<span class="kw">async </span>{ |
| <span class="kw">let </span>blocking_result = task::block_in_place(|| { |
| <span class="comment">// ... |
| </span>}); |
| <span class="comment">// ... |
| </span>}); |
| join.<span class="kw">await</span>.unwrap(); |
| })</code></pre></div> |
| <p>This, however, will not panic:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::runtime::Runtime; |
| <span class="kw">use </span>tokio::task; |
| |
| <span class="kw">let </span>rt = Runtime::new().unwrap(); |
| <span class="kw">let </span>local = task::LocalSet::new(); |
| local.block_on(<span class="kw-2">&</span>rt, <span class="kw">async </span>{ |
| <span class="kw">let </span>join = task::spawn_local(<span class="kw">async </span>{ |
| <span class="kw">let </span>blocking_result = task::spawn_blocking(|| { |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>; |
| <span class="comment">// ... |
| </span>}); |
| join.<span class="kw">await</span>.unwrap(); |
| })</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.run_until" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#566-575">source</a><h4 class="code-header">pub async fn <a href="#method.run_until" class="fnname">run_until</a><F>(&self, future: F) -> F::Output<span class="where fmt-newline">where<br> F: Future,</span></h4></section></summary><div class="docblock"><p>Runs a future to completion on the local set, returning its output.</p> |
| <p>This returns a future that runs the given future with a local set, |
| allowing it to call <a href="fn.spawn_local.html"><code>spawn_local</code></a> to spawn additional <code>!Send</code> futures. |
| Any local futures spawned on the local set will be driven in the |
| background until the future passed to <code>run_until</code> completes. When the future |
| passed to <code>run</code> finishes, any local futures which have not completed |
| will remain on the local set, and will be driven on subsequent calls to |
| <code>run_until</code> or when <a href="#awaiting-a-localset">awaiting the local set</a> itself.</p> |
| <h5 id="examples-1"><a href="#examples-1">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::task; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| task::LocalSet::new().run_until(<span class="kw">async </span>{ |
| task::spawn_local(<span class="kw">async move </span>{ |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>.unwrap(); |
| <span class="comment">// ... |
| </span>}).<span class="kw">await</span>; |
| }</code></pre></div> |
| </div></details></div></details></div><h2 id="trait-implementations" class="small-section-header">Trait Implementations<a href="#trait-implementations" class="anchor"></a></h2><div id="trait-implementations-list"><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Debug-for-LocalSet" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#792-796">source</a><a href="#impl-Debug-for-LocalSet" class="anchor"></a><h3 class="code-header">impl Debug for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.fmt" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#793-795">source</a><a href="#method.fmt" class="anchor"></a><h4 class="code-header">fn <a class="fnname">fmt</a>(&self, fmt: &mut Formatter<'_>) -> Result</h4></section></summary><div class='docblock'>Formats the value using the given formatter. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Default-for-LocalSet" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#825-829">source</a><a href="#impl-Default-for-LocalSet" class="anchor"></a><h3 class="code-header">impl Default for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.default" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#826-828">source</a><a href="#method.default" class="anchor"></a><h4 class="code-header">fn <a class="fnname">default</a>() -> <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</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.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></span><code class="content"><span class="where fmt-newline">impl Future for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></span><span class="where fmt-newline"> type <a class="associatedtype">Output</a> = ();</span></code></span></span></span></span></h4></section></summary><div class='docblock'>Returns the “default value” for a type. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Drop-for-LocalSet" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#831-875">source</a><a href="#impl-Drop-for-LocalSet" class="anchor"></a><h3 class="code-header">impl Drop for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.drop" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#832-874">source</a><a href="#method.drop" class="anchor"></a><h4 class="code-header">fn <a class="fnname">drop</a>(&mut self)</h4></section></summary><div class='docblock'>Executes the destructor for this type. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Future-for-LocalSet" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#798-823">source</a><a href="#impl-Future-for-LocalSet" class="anchor"></a><h3 class="code-header">impl Future for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Output" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Output" class="anchor"></a><h4 class="code-header">type <a class="associatedtype">Output</a> = ()</h4></section></summary><div class='docblock'>The type of value produced on completion.</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.poll" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../src/tokio/task/local.rs.html#801-822">source</a><a href="#method.poll" class="anchor"></a><h4 class="code-header">fn <a class="fnname">poll</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output></h4></section></summary><div class='docblock'>Attempt to resolve the future to a final value, registering |
| the current task for wakeup if the value is not yet available. <a>Read more</a></div></details></div></details></div><h2 id="synthetic-implementations" class="small-section-header">Auto Trait Implementations<a href="#synthetic-implementations" class="anchor"></a></h2><div id="synthetic-implementations-list"><section id="impl-RefUnwindSafe-for-LocalSet" class="impl has-srclink"><a href="#impl-RefUnwindSafe-for-LocalSet" class="anchor"></a><h3 class="code-header">impl !RefUnwindSafe for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section><section id="impl-Send-for-LocalSet" class="impl has-srclink"><a href="#impl-Send-for-LocalSet" class="anchor"></a><h3 class="code-header">impl !Send for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section><section id="impl-Sync-for-LocalSet" class="impl has-srclink"><a href="#impl-Sync-for-LocalSet" class="anchor"></a><h3 class="code-header">impl !Sync for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section><section id="impl-Unpin-for-LocalSet" class="impl has-srclink"><a href="#impl-Unpin-for-LocalSet" class="anchor"></a><h3 class="code-header">impl Unpin for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section><section id="impl-UnwindSafe-for-LocalSet" class="impl has-srclink"><a href="#impl-UnwindSafe-for-LocalSet" class="anchor"></a><h3 class="code-header">impl !UnwindSafe for <a class="struct" href="struct.LocalSet.html" title="struct tokio::task::LocalSet">LocalSet</a></h3></section></div><h2 id="blanket-implementations" class="small-section-header">Blanket Implementations<a href="#blanket-implementations" class="anchor"></a></h2><div id="blanket-implementations-list"><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Any-for-LocalSet" class="impl has-srclink"><a href="#impl-Any-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T> Any for T<span class="where fmt-newline">where<br> T: 'static + ?Sized,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.type_id" class="method trait-impl has-srclink"><a href="#method.type_id" class="anchor"></a><h4 class="code-header">fn <a class="fnname">type_id</a>(&self) -> TypeId</h4></section></summary><div class='docblock'>Gets the <code>TypeId</code> of <code>self</code>. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Borrow%3CT%3E-for-LocalSet" class="impl has-srclink"><a href="#impl-Borrow%3CT%3E-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T> Borrow<T> for T<span class="where fmt-newline">where<br> T: ?Sized,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.borrow" class="method trait-impl has-srclink"><span class="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span><a href="#method.borrow" class="anchor"></a><h4 class="code-header">fn <a class="fnname">borrow</a>(&self) -> &T</h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-BorrowMut%3CT%3E-for-LocalSet" class="impl has-srclink"><a href="#impl-BorrowMut%3CT%3E-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T> BorrowMut<T> for T<span class="where fmt-newline">where<br> T: ?Sized,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.borrow_mut" class="method trait-impl has-srclink"><span class="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span><a href="#method.borrow_mut" class="anchor"></a><h4 class="code-header">fn <a class="fnname">borrow_mut</a>(&mut self) -> &mut T</h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-From%3CT%3E-for-LocalSet" class="impl has-srclink"><a href="#impl-From%3CT%3E-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T> From<T> for T</h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.from" class="method trait-impl has-srclink"><span class="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.from" class="anchor"></a><h4 class="code-header">fn <a class="fnname">from</a>(t: T) -> T</h4></section></summary><div class="docblock"><p>Returns the argument unchanged.</p> |
| </div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Into%3CU%3E-for-LocalSet" class="impl has-srclink"><a href="#impl-Into%3CU%3E-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T, U> Into<U> for T<span class="where fmt-newline">where<br> U: From<T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.into" class="method trait-impl has-srclink"><span class="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.into" class="anchor"></a><h4 class="code-header">fn <a class="fnname">into</a>(self) -> U</h4></section></summary><div class="docblock"><p>Calls <code>U::from(self)</code>.</p> |
| <p>That is, this conversion is whatever the implementation of |
| <code>[From]<T> for U</code> chooses to do.</p> |
| </div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-IntoFuture-for-LocalSet" class="impl has-srclink"><a href="#impl-IntoFuture-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<F> IntoFuture for F<span class="where fmt-newline">where<br> F: Future,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Output-1" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Output-1" class="anchor"></a><h4 class="code-header">type <a class="associatedtype">Output</a> = <F as Future>::Output</h4></section></summary><div class='docblock'>The output that the future will produce on completion.</div></details><details class="rustdoc-toggle" open><summary><section id="associatedtype.IntoFuture" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.IntoFuture" class="anchor"></a><h4 class="code-header">type <a class="associatedtype">IntoFuture</a> = F</h4></section></summary><div class='docblock'>Which kind of future are we turning this into?</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.into_future" class="method trait-impl has-srclink"><a href="#method.into_future" class="anchor"></a><h4 class="code-header">fn <a class="fnname">into_future</a>(self) -> <F as IntoFuture>::IntoFuture</h4></section></summary><div class='docblock'>Creates a future from a value. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-TryFrom%3CU%3E-for-LocalSet" class="impl has-srclink"><a href="#impl-TryFrom%3CU%3E-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T, U> TryFrom<U> for T<span class="where fmt-newline">where<br> U: Into<T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Error-1" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-1" class="anchor"></a><h4 class="code-header">type <a class="associatedtype">Error</a> = Infallible</h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_from" class="method trait-impl has-srclink"><span class="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.try_from" class="anchor"></a><h4 class="code-header">fn <a class="fnname">try_from</a>(value: U) -> Result<T, <T as TryFrom<U>>::Error></h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-TryInto%3CU%3E-for-LocalSet" class="impl has-srclink"><a href="#impl-TryInto%3CU%3E-for-LocalSet" class="anchor"></a><h3 class="code-header">impl<T, U> TryInto<U> for T<span class="where fmt-newline">where<br> U: TryFrom<T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Error" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error" class="anchor"></a><h4 class="code-header">type <a class="associatedtype">Error</a> = <U as TryFrom<T>>::Error</h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_into" class="method trait-impl has-srclink"><span class="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.try_into" class="anchor"></a><h4 class="code-header">fn <a class="fnname">try_into</a>(self) -> Result<U, <U as TryFrom<T>>::Error></h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details></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> |
