215 lines
12 KiB
HTML
215 lines
12 KiB
HTML
|
<!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 `thread_local` crate.">
|
|||
|
|
<meta name="keywords" content="rust, rustlang, rust-lang, thread_local">
|
|||
|
|
|
|||
|
|
<title>thread_local - Rust</title>
|
|||
|
|
|
|||
|
|
<link rel="stylesheet" type="text/css" href="../normalize.css">
|
|||
|
|
<link rel="stylesheet" type="text/css" href="../rustdoc.css">
|
|||
|
|
<link rel="stylesheet" type="text/css" href="../main.css">
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</head>
|
|||
|
|
<body class="rustdoc mod">
|
|||
|
|
<!--[if lte IE 8]>
|
|||
|
|
<div class="warning">
|
|||
|
|
This old browser is unsupported and will most likely display funky
|
|||
|
|
things.
|
|||
|
|
</div>
|
|||
|
|
<![endif]-->
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<nav class="sidebar">
|
|||
|
|
|
|||
|
|
<p class='location'>Crate thread_local</p><div class="block items"><ul><li><a href="#structs">Structs</a></li><li><a href="#types">Type Definitions</a></li></ul></div><p class='location'></p><script>window.sidebarCurrent = {name: 'thread_local', ty: 'mod', relpath: '../'};</script>
|
|||
|
|
</nav>
|
|||
|
|
|
|||
|
|
<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">
|
|||
|
|
</div>
|
|||
|
|
</form>
|
|||
|
|
</nav>
|
|||
|
|
|
|||
|
|
<section id='main' class="content">
|
|||
|
|
<h1 class='fqn'><span class='in-band'>Crate <a class="mod" href=''>thread_local</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/thread_local/lib.rs.html#8-773' title='goto source code'>[src]</a></span></h1>
|
|||
|
|
<div class='docblock'><p>Per-object thread-local storage</p>
|
|||
|
|
|
|||
|
|
<p>This library provides the <code>ThreadLocal</code> type which allows a separate copy of
|
|||
|
|
an object to be used for each thread. This allows for per-object
|
|||
|
|
thread-local storage, unlike the standard library's <code>thread_local!</code> macro
|
|||
|
|
which only allows static thread-local storage.</p>
|
|||
|
|
|
|||
|
|
<p>Per-thread objects are not destroyed when a thread exits. Instead, objects
|
|||
|
|
are only destroyed when the <code>ThreadLocal</code> containing them is destroyed.</p>
|
|||
|
|
|
|||
|
|
<p>You can also iterate over the thread-local values of all thread in a
|
|||
|
|
<code>ThreadLocal</code> object using the <code>iter_mut</code> and <code>into_iter</code> methods. This can
|
|||
|
|
only be done if you have mutable access to the <code>ThreadLocal</code> object, which
|
|||
|
|
guarantees that you are the only thread currently accessing it.</p>
|
|||
|
|
|
|||
|
|
<p>A <code>CachedThreadLocal</code> type is also provided which wraps a <code>ThreadLocal</code> but
|
|||
|
|
also uses a special fast path for the first thread that writes into it. The
|
|||
|
|
fast path has very low overhead (<1ns per access) while keeping the same
|
|||
|
|
performance as <code>ThreadLocal</code> for other threads.</p>
|
|||
|
|
|
|||
|
|
<p>Note that since thread IDs are recycled when a thread exits, it is possible
|
|||
|
|
for one thread to retrieve the object of another thread. Since this can only
|
|||
|
|
occur after a thread has exited this does not lead to any race conditions.</p>
|
|||
|
|
|
|||
|
|
<h1 id='examples' class='section-header'><a href='#examples'>Examples</a></h1>
|
|||
|
|
<p>Basic usage of <code>ThreadLocal</code>:</p>
|
|||
|
|
|
|||
|
|
<pre class="rust rust-example-rendered">
|
|||
|
|
<span class="kw">use</span> <span class="ident">thread_local</span>::<span class="ident">ThreadLocal</span>;
|
|||
|
|
<span class="kw">let</span> <span class="ident">tls</span>: <span class="ident">ThreadLocal</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span> <span class="op">=</span> <span class="ident">ThreadLocal</span>::<span class="ident">new</span>();
|
|||
|
|
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">tls</span>.<span class="ident">get</span>(), <span class="prelude-val">None</span>);
|
|||
|
|
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">tls</span>.<span class="ident">get_or</span>(<span class="op">||</span> <span class="ident">Box</span>::<span class="ident">new</span>(<span class="number">5</span>)), <span class="kw-2">&</span><span class="number">5</span>);
|
|||
|
|
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">tls</span>.<span class="ident">get</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="number">5</span>));</pre>
|
|||
|
|
|
|||
|
|
<p>Combining thread-local values into a single result:</p>
|
|||
|
|
|
|||
|
|
<pre class="rust rust-example-rendered">
|
|||
|
|
<span class="kw">use</span> <span class="ident">thread_local</span>::<span class="ident">ThreadLocal</span>;
|
|||
|
|
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::<span class="ident">Arc</span>;
|
|||
|
|
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">cell</span>::<span class="ident">Cell</span>;
|
|||
|
|
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">thread</span>;
|
|||
|
|
|
|||
|
|
<span class="kw">let</span> <span class="ident">tls</span> <span class="op">=</span> <span class="ident">Arc</span>::<span class="ident">new</span>(<span class="ident">ThreadLocal</span>::<span class="ident">new</span>());
|
|||
|
|
|
|||
|
|
<span class="comment">// Create a bunch of threads to do stuff</span>
|
|||
|
|
<span class="kw">for</span> _ <span class="kw">in</span> <span class="number">0</span>..<span class="number">5</span> {
|
|||
|
|
<span class="kw">let</span> <span class="ident">tls2</span> <span class="op">=</span> <span class="ident">tls</span>.<span class="ident">clone</span>();
|
|||
|
|
<span class="ident">thread</span>::<span class="ident">spawn</span>(<span class="kw">move</span> <span class="op">||</span> {
|
|||
|
|
<span class="comment">// Increment a counter to count some event...</span>
|
|||
|
|
<span class="kw">let</span> <span class="ident">cell</span> <span class="op">=</span> <span class="ident">tls2</span>.<span class="ident">get_or</span>(<span class="op">||</span> <span class="ident">Box</span>::<span class="ident">new</span>(<span class="ident">Cell</span>::<span class="ident">new</span>(<span class="number">0</span>)));
|
|||
|
|
<span class="ident">cell</span>.<span class="ident">set</span>(<span class="ident">cell</span>.<span class="ident">get</span>() <span class="op">+</span> <span class="number">1</span>);
|
|||
|
|
}).<span class="ident">join</span>().<span class="ident">unwrap</span>();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
<span class="comment">// Once all threads are done, collect the counter values and return the</span>
|
|||
|
|
<span class="comment">// sum of all thread-local counter values.</span>
|
|||
|
|
<span class="kw">let</span> <span class="ident">tls</span> <span class="op">=</span> <span class="ident">Arc</span>::<span class="ident">try_unwrap</span>(<span class="ident">tls</span>).<span class="ident">unwrap</span>();
|
|||
|
|
<span class="kw">let</span> <span class="ident">total</span> <span class="op">=</span> <span class="ident">tls</span>.<span class="ident">into_iter</span>().<span class="ident">fold</span>(<span class="number">0</span>, <span class="op">|</span><span class="ident">x</span>, <span class="ident">y</span><span class="op">|</span> <span class="ident">x</span> <span class="op">+</span> <span class="ident">y</span>.<span class="ident">get</span>());
|
|||
|
|
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">total</span>, <span class="number">5</span>);</pre>
|
|||
|
|
</div><h2 id='structs' class='section-header'><a href="#structs">Structs</a></h2>
|
|||
|
|
<table>
|
|||
|
|
<tr class=' module-item'>
|
|||
|
|
<td><a class="struct" href="struct.CachedThreadLocal.html"
|
|||
|
|
title='struct thread_local::CachedThreadLocal'>CachedThreadLocal</a></td>
|
|||
|
|
<td class='docblock-short'>
|
|||
|
|
<p>Wrapper around <code>ThreadLocal</code> which adds a fast path for a single thread.</p>
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class=' module-item'>
|
|||
|
|
<td><a class="struct" href="struct.IntoIter.html"
|
|||
|
|
title='struct thread_local::IntoIter'>IntoIter</a></td>
|
|||
|
|
<td class='docblock-short'>
|
|||
|
|
<p>An iterator that moves out of a <code>ThreadLocal</code>.</p>
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class=' module-item'>
|
|||
|
|
<td><a class="struct" href="struct.IterMut.html"
|
|||
|
|
title='struct thread_local::IterMut'>IterMut</a></td>
|
|||
|
|
<td class='docblock-short'>
|
|||
|
|
<p>Mutable iterator over the contents of a <code>ThreadLocal</code>.</p>
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class=' module-item'>
|
|||
|
|
<td><a class="struct" href="struct.ThreadLocal.html"
|
|||
|
|
title='struct thread_local::ThreadLocal'>ThreadLocal</a></td>
|
|||
|
|
<td class='docblock-short'>
|
|||
|
|
<p>Thread-local variable wrapper</p>
|
|||
|
|
</td>
|
|||
|
|
</tr></table><h2 id='types' class='section-header'><a href="#types">Type Definitions</a></h2>
|
|||
|
|
<table>
|
|||
|
|
<tr class=' module-item'>
|
|||
|
|
<td><a class="type" href="type.CachedIntoIter.html"
|
|||
|
|
title='type thread_local::CachedIntoIter'>CachedIntoIter</a></td>
|
|||
|
|
<td class='docblock-short'>
|
|||
|
|
<p>An iterator that moves out of a <code>CachedThreadLocal</code>.</p>
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class=' module-item'>
|
|||
|
|
<td><a class="type" href="type.CachedIterMut.html"
|
|||
|
|
title='type thread_local::CachedIterMut'>CachedIterMut</a></td>
|
|||
|
|
<td class='docblock-short'>
|
|||
|
|
<p>Mutable iterator over the contents of a <code>CachedThreadLocal</code>.</p>
|
|||
|
|
</td>
|
|||
|
|
</tr></table></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>?</dt>
|
|||
|
|
<dd>Show this help dialog</dd>
|
|||
|
|
<dt>S</dt>
|
|||
|
|
<dd>Focus the search field</dd>
|
|||
|
|
<dt>⇤</dt>
|
|||
|
|
<dd>Move up in search results</dd>
|
|||
|
|
<dt>⇥</dt>
|
|||
|
|
<dd>Move down in search results</dd>
|
|||
|
|
<dt>⏎</dt>
|
|||
|
|
<dd>Go to active search result</dd>
|
|||
|
|
<dt>+</dt>
|
|||
|
|
<dd>Collapse/expand 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>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</aside>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<script>
|
|||
|
|
window.rootPath = "../";
|
|||
|
|
window.currentCrate = "thread_local";
|
|||
|
|
</script>
|
|||
|
|
<script src="../main.js"></script>
|
|||
|
|
<script defer src="../search-index.js"></script>
|
|||
|
|
</body>
|
|||
|
|
</html>
|