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<!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 `get_physical` fn in crate `num_cpus`."><meta name="keywords" content="rust, rustlang, rust-lang, get_physical"><title>num_cpus::get_physical - 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><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="shortcut icon" href="../favicon.ico"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><body class="rustdoc fn"><!--[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='../num_cpus/index.html'><div class='logo-container'><img src='../rust-logo.png' alt='logo'></div></a><div class="sidebar-elems"><p class='location'><a href='index.html'>num_cpus</a></p><script>window.sidebarCurrent = {name: 'get_physical', ty: 'fn', 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"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><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='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/num_cpus/lib.rs.html#101-103' title='goto source code'>[src]</a></span><span class='in-band'>Function <a href='index.html'>num_cpus</a>::<wbr><a class="fn" href=''>get_physical</a></span></h1><pre class='rust fn'>pub fn get_physical() -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a></pre><div class='docblock'><p>Returns the number of physical cores of the current system.</p>
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<h1 id="note" class="section-header"><a href="#note">Note</a></h1>
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<p>Physical count is supported only on Linux, mac OS and Windows platforms.
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On other platforms, or if the physical count fails on supported platforms,
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this function returns the same as <a href="fn.get.html"><code>get()</code></a>, which is the number of logical
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CPUS.</p>
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<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
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<div class="example-wrap"><pre class="rust rust-example-rendered">
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<span class="kw">let</span> <span class="ident">logical_cpus</span> <span class="op">=</span> <span class="ident">num_cpus</span>::<span class="ident">get</span>();
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<span class="kw">let</span> <span class="ident">physical_cpus</span> <span class="op">=</span> <span class="ident">num_cpus</span>::<span class="ident">get_physical</span>();
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<span class="kw">if</span> <span class="ident">logical_cpus</span> <span class="op">></span> <span class="ident">physical_cpus</span> {
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"We have simultaneous multithreading with about {:.2} \
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logical cores to 1 physical core."</span>,
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(<span class="ident">logical_cpus</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">/</span> (<span class="ident">physical_cpus</span> <span class="kw">as</span> <span class="ident">f64</span>));
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} <span class="kw">else</span> <span class="kw">if</span> <span class="ident">logical_cpus</span> <span class="op">=</span><span class="op">=</span> <span class="ident">physical_cpus</span> {
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"Either we don't have simultaneous multithreading, or our \
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system doesn't support getting the number of physical CPUs."</span>);
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} <span class="kw">else</span> {
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"We have less logical CPUs than physical CPUs, maybe we only have access to \
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some of the CPUs on our system."</span>);
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}</pre></div>
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