| <!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="Fires off a task into the Rayon threadpool in the “static” or “global” scope. Just like a standard thread, this task is not tied to the current stack frame, and hence it cannot hold any references other than those with `'static` lifetime. If you want to spawn a task that references stack data, use the `scope()` function to create a scope."><meta name="keywords" content="rust, rustlang, rust-lang, spawn"><title>spawn in rayon_core - 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 fn"><!--[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="../rayon_core/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="../rayon_core/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><div class="sidebar-elems"><h2><a href="index.html">In rayon_core</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">Function <a href="index.html">rayon_core</a>::<wbr><a class="fn" href="#">spawn</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/rayon_core/spawn/mod.rs.html#60-66">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 fn"><code>pub fn spawn<F>(func: F)<span class="where fmt-newline">where<br> F: FnOnce() + Send + 'static,</span></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Fires off a task into the Rayon threadpool in the “static” or |
| “global” scope. Just like a standard thread, this task is not |
| tied to the current stack frame, and hence it cannot hold any |
| references other than those with <code>'static</code> lifetime. If you want |
| to spawn a task that references stack data, use <a href="fn.scope.html">the <code>scope()</code> |
| function</a> to create a scope.</p> |
| <p>Since tasks spawned with this function cannot hold references into |
| the enclosing stack frame, you almost certainly want to use a |
| <code>move</code> closure as their argument (otherwise, the closure will |
| typically hold references to any variables from the enclosing |
| function that you happen to use).</p> |
| <p>This API assumes that the closure is executed purely for its |
| side-effects (i.e., it might send messages, modify data protected |
| by a mutex, or some such thing).</p> |
| <p>There is no guaranteed order of execution for spawns, given that |
| other threads may steal tasks at any time. However, they are |
| generally prioritized in a LIFO order on the thread from which |
| they were spawned. Other threads always steal from the other end of |
| the deque, like FIFO order. The idea is that “recent” tasks are |
| most likely to be fresh in the local CPU’s cache, while other |
| threads can steal older “stale” tasks. For an alternate approach, |
| consider <a href="fn.spawn_fifo.html"><code>spawn_fifo()</code></a> instead.</p> |
| <h2 id="panic-handling"><a href="#panic-handling">Panic handling</a></h2> |
| <p>If this closure should panic, the resulting panic will be |
| propagated to the panic handler registered in the <code>ThreadPoolBuilder</code>, |
| if any. See <a href="struct.ThreadPoolBuilder.html#method.panic_handler"><code>ThreadPoolBuilder::panic_handler()</code></a> for more |
| details.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <p>This code creates a Rayon task that increments a global counter.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT}; |
| |
| <span class="kw">static </span>GLOBAL_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT; |
| |
| rayon::spawn(<span class="kw">move </span>|| { |
| GLOBAL_COUNTER.fetch_add(<span class="number">1</span>, Ordering::SeqCst); |
| });</code></pre></div> |
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