| 12345678910111213141516171819202122232425262728293031323334353637383940414243 |
- <!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="API documentation for the Rust `LocalKey` struct in crate `futures`."><meta name="keywords" content="rust, rustlang, rust-lang, LocalKey"><title>futures::task::LocalKey - Rust</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css"><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script src="../../storage.js"></script></head><body class="rustdoc struct"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><p class='location'>Struct LocalKey</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#methods">Methods</a><div class="sidebar-links"><a href="#method.with">with</a></div><a class="sidebar-title" href="#implementations">Trait Implementations</a><div class="sidebar-links"><a href="#impl-Debug">Debug</a></div><a class="sidebar-title" href="#synthetic-implementations">Auto Trait Implementations</a><div class="sidebar-links"><a href="#impl-Send">Send</a><a href="#impl-Sync">Sync</a></div></div><p class='location'><a href='../index.html'>futures</a>::<wbr><a href='index.html'>task</a></p><script>window.sidebarCurrent = {name: 'LocalKey', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='in-band'>Struct <a href='../index.html'>futures</a>::<wbr><a href='index.html'>task</a>::<wbr><a class="struct" href=''>LocalKey</a></span><span class='out-of-band'><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../../src/futures/task_impl/std/data.rs.html#59-66' title='goto source code'>[src]</a></span></h1><div class="docblock type-decl"><pre class='rust struct'>pub struct LocalKey<T> { /* fields omitted */ }</pre></div><div class='docblock'><p>A key for task-local data stored in a future's task.</p>
- <p>This type is generated by the <code>task_local!</code> macro and performs very
- similarly to the <code>thread_local!</code> macro and <code>std::thread::LocalKey</code> types.
- Data associated with a <code>LocalKey<T></code> is stored inside of a future's task,
- and the data is destroyed when the future is completed and the task is
- destroyed.</p>
- <p>Task-local data can migrate between threads and hence requires a <code>Send</code>
- bound. Additionally, task-local data also requires the <code>'static</code> bound to
- ensure it lives long enough. When a key is accessed for the first time the
- task's data is initialized with the provided initialization expression to
- the macro.</p>
- </div>
- <h2 id='methods' class='small-section-header'>
- Methods<a href='#methods' class='anchor'></a>
- </h2>
- <h3 id='impl' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> + 'static> <a class="struct" href="../../futures/task/struct.LocalKey.html" title="struct futures::task::LocalKey">LocalKey</a><T></code><a href='#impl' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/futures/task_impl/std/data.rs.html#93-131' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.with' class="method"><span id='with.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.with' class='fnname'>with</a><F, R>(&'static self, f: F) -> R <span class="where fmt-newline">where<br> F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>(<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>T) -> R, </span></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/futures/task_impl/std/data.rs.html#114-130' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Access this task-local key, running the provided closure with a
- reference to the value.</p>
- <p>This function will access this task-local key to retrieve the data
- associated with the current task and this key. If this is the first time
- this key has been accessed on this task, then the key will be
- initialized with the initialization expression provided at the time the
- <code>task_local!</code> macro was called.</p>
- <p>The provided closure will be provided a shared reference to the
- underlying data associated with this task-local-key. The data itself is
- stored inside of the current task.</p>
- <h1 id="panics" class="section-header"><a href="#panics">Panics</a></h1>
- <p>This function can possibly panic for a number of reasons:</p>
- <ul>
- <li>If there is not a current task.</li>
- <li>If the initialization expression is run and it panics</li>
- <li>If the closure provided panics</li>
- </ul>
- </div></div>
- <h2 id='implementations' class='small-section-header'>
- Trait Implementations<a href='#implementations' class='anchor'></a>
- </h2>
- <div id='implementations-list'><h3 id='impl-Debug' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a>> <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="../../futures/task/struct.LocalKey.html" title="struct futures::task::LocalKey">LocalKey</a><T></code><a href='#impl-Debug' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/futures/task_impl/std/data.rs.html#58' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.fmt' class="method"><span id='fmt.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&self, f: &mut <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>) -> <a class="type" href="https://doc.rust-lang.org/nightly/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/futures/task_impl/std/data.rs.html#58' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Formats the value using the given formatter. <a href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></p>
- </div></div></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'>
- <h3 id='impl-Send' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="../../futures/task/struct.LocalKey.html" title="struct futures::task::LocalKey">LocalKey</a><T></code><a href='#impl-Send' class='anchor'></a></span></td><td><span class='out-of-band'></span></td></tr></tbody></table></h3><div class='impl-items'></div><h3 id='impl-Sync' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="../../futures/task/struct.LocalKey.html" title="struct futures::task::LocalKey">LocalKey</a><T></code><a href='#impl-Sync' class='anchor'></a></span></td><td><span class='out-of-band'></span></td></tr></tbody></table></h3><div class='impl-items'></div></div></section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../";window.currentCrate = "futures";</script><script src="../../aliases.js"></script><script src="../../main.js"></script><script defer src="../../search-index.js"></script></body></html>
|
