<!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 `Ordering` enum in crate `core`."> <meta name="keywords" content="rust, rustlang, rust-lang, Ordering"> <title>core::sync::atomic::Ordering - 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="../../../main.css" id="themeStyle"> <script src="../../../storage.js"></script> <link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"> </head> <body class="rustdoc enum"> <!--[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> <a href='../../../core/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a> <p class='location'>Enum Ordering</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#variants">Variants</a><div class="sidebar-links"><a href="#variant.Relaxed">Relaxed</a><a href="#variant.Release">Release</a><a href="#variant.Acquire">Acquire</a><a href="#variant.AcqRel">AcqRel</a><a href="#variant.SeqCst">SeqCst</a></div><a class="sidebar-title" href="#implementations">Trait Implementations</a><div class="sidebar-links"><a href="#impl-Copy">Copy</a><a href="#impl-Clone">Clone</a><a href="#impl-Debug">Debug</a></div></div><p class='location'><a href='../../index.html'>core</a>::<wbr><a href='../index.html'>sync</a>::<wbr><a href='index.html'>atomic</a></p><script>window.sidebarCurrent = {name: 'Ordering', ty: 'enum', 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"> </div> </form> </nav> <section id='main' class="content"> <h1 class='fqn'><span class='in-band'>Enum <a href='../../index.html'>core</a>::<wbr><a href='../index.html'>sync</a>::<wbr><a href='index.html'>atomic</a>::<wbr><a class="enum" href=''>Ordering</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><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/core/sync/atomic.rs.html#185-222' title='goto source code'>[src]</a></span></h1> <pre class='rust enum'>pub enum Ordering { Relaxed, Release, Acquire, AcqRel, SeqCst, // some variants omitted }</pre><div class='docblock'><p>Atomic memory orderings</p> <p>Memory orderings limit the ways that both the compiler and CPU may reorder instructions around atomic operations. At its most restrictive, "sequentially consistent" atomics allow neither reads nor writes to be moved either before or after the atomic operation; on the other end "relaxed" atomics allow all reorderings.</p> <p>Rust's memory orderings are <a href="http://llvm.org/docs/LangRef.html#memory-model-for-concurrent-operations">the same as LLVM's</a>.</p> <p>For more information see the <a href="../../../nomicon/atomics.html">nomicon</a>.</p> </div><h2 id='variants' class='variants small-section-header'> Variants<a href='#variants' class='anchor'></a></h2> <span id="variant.Relaxed" class="variant small-section-header"><a href="#variant.Relaxed" class="anchor field"></a><span id='Relaxed.v' class='invisible'><code>Relaxed</code></span></span><div class='docblock'><p>No ordering constraints, only atomic operations.</p> <p>Corresponds to LLVM's <a href="http://llvm.org/docs/Atomics.html#monotonic"><code>Monotonic</code></a> ordering.</p> </div><span id="variant.Release" class="variant small-section-header"><a href="#variant.Release" class="anchor field"></a><span id='Release.v' class='invisible'><code>Release</code></span></span><div class='docblock'><p>When coupled with a store, all previous writes become visible to the other threads that perform a load with <a href="http://llvm.org/docs/Atomics.html#acquire"><code>Acquire</code></a> ordering on the same value.</p> </div><span id="variant.Acquire" class="variant small-section-header"><a href="#variant.Acquire" class="anchor field"></a><span id='Acquire.v' class='invisible'><code>Acquire</code></span></span><div class='docblock'><p>When coupled with a load, all subsequent loads will see data written before a store with <a href="http://llvm.org/docs/Atomics.html#release"><code>Release</code></a> ordering on the same value in other threads.</p> </div><span id="variant.AcqRel" class="variant small-section-header"><a href="#variant.AcqRel" class="anchor field"></a><span id='AcqRel.v' class='invisible'><code>AcqRel</code></span></span><div class='docblock'><p>When coupled with a load, uses <a href="http://llvm.org/docs/Atomics.html#acquire"><code>Acquire</code></a> ordering, and with a store <a href="http://llvm.org/docs/Atomics.html#release"><code>Release</code></a> ordering.</p> </div><span id="variant.SeqCst" class="variant small-section-header"><a href="#variant.SeqCst" class="anchor field"></a><span id='SeqCst.v' class='invisible'><code>SeqCst</code></span></span><div class='docblock'><p>Like <code>AcqRel</code> with the additional guarantee that all threads see all sequentially consistent operations in the same order.</p> </div> <h2 id='implementations' class='small-section-header'> Trait Implementations<a href='#implementations' class='anchor'></a> </h2> <h3 id='impl-Copy' class='impl'><span class='in-band'><code>impl <a class="trait" href="../../../core/marker/trait.Copy.html" title="trait core::marker::Copy">Copy</a> for <a class="enum" href="../../../core/sync/atomic/enum.Ordering.html" title="enum core::sync::atomic::Ordering">Ordering</a></code><a href='#impl-Copy' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/sync/atomic.rs.html#184' title='goto source code'>[src]</a></span></h3> <div class='impl-items'></div><h3 id='impl-Clone' class='impl'><span class='in-band'><code>impl <a class="trait" href="../../../core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a> for <a class="enum" href="../../../core/sync/atomic/enum.Ordering.html" title="enum core::sync::atomic::Ordering">Ordering</a></code><a href='#impl-Clone' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/sync/atomic.rs.html#184' title='goto source code'>[src]</a></span></h3> <div class='impl-items'><h4 id='method.clone' class="method"><span id='clone.v' class='invisible'><code>fn <a href='../../../core/clone/trait.Clone.html#tymethod.clone' class='fnname'>clone</a>(&self) -> <a class="enum" href="../../../core/sync/atomic/enum.Ordering.html" title="enum core::sync::atomic::Ordering">Ordering</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/sync/atomic.rs.html#184' title='goto source code'>[src]</a></span></h4> <div class='docblock'><p>Returns a copy of the value. <a href="../../../core/clone/trait.Clone.html#tymethod.clone">Read more</a></p> </div><h4 id='method.clone_from' class="method"><span id='clone_from.v' class='invisible'><code>fn <a href='../../../core/clone/trait.Clone.html#method.clone_from' class='fnname'>clone_from</a>(&mut self, source: &Self)</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/clone.rs.html#112-114' title='goto source code'>[src]</a></span></h4> <div class='docblock'><p>Performs copy-assignment from <code>source</code>. <a href="../../../core/clone/trait.Clone.html#method.clone_from">Read more</a></p> </div></div><h3 id='impl-Debug' class='impl'><span class='in-band'><code>impl <a class="trait" href="../../../core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="enum" href="../../../core/sync/atomic/enum.Ordering.html" title="enum core::sync::atomic::Ordering">Ordering</a></code><a href='#impl-Debug' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/sync/atomic.rs.html#184' title='goto source code'>[src]</a></span></h3> <div class='impl-items'><h4 id='method.fmt' class="method"><span id='fmt.v' class='invisible'><code>fn <a href='../../../core/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&self, __arg_0: &mut <a class="struct" href="../../../core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>) -> <a class="type" href="../../../core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/sync/atomic.rs.html#184' title='goto source code'>[src]</a></span></h4> <div class='docblock'><p>Formats the value using the given formatter. <a href="../../../core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></p> </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> 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