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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="Puts the task into the Rayon threadpools job queue 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 `&#x27;static` lifetime. If you want to spawn a task that references stack data, use the `scope()` function to create a scope."><title>spawn in rayon - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-ac92e1bbe349e143.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="rayon" data-themes="" data-resource-suffix="" data-rustdoc-version="1.76.0 (07dca489a 2024-02-04)" data-channel="1.76.0" data-search-js="search-2b6ce74ff89ae146.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../static.files/storage-f2adc0d6ca4d09fb.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-305769736d49e732.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-feafe1bb7466e4bd.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-16x16-8b506e7a72182f1c.png"><link rel="alternate icon" type="image/png" href="../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../static.files/favicon-2c020d218678b618.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">&#9776;</button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../rayon/index.html">rayon</a><span class="version">1.10.0</span></h2></div><div class="sidebar-elems"></div></nav><div class="sidebar-resizer"></div>
<main><div class="width-limiter"><nav class="sub"><form class="search-form"><span></span><div id="sidebar-button" tabindex="-1"><a href="../rayon/all.html" title="show sidebar"></a></div><input class="search-input" name="search" aria-label="Run search in the documentation" autocomplete="off" spellcheck="false" placeholder="Click or press S to search, ? for more options…" type="search"><div id="help-button" tabindex="-1"><a href="../help.html" title="help">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1>Function <a href="index.html">rayon</a>::<wbr><a class="fn" href="#">spawn</a><button id="copy-path" title="Copy item path to clipboard"><img src="../static.files/clipboard-7571035ce49a181d.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="src" href="../src/rayon_core/spawn/mod.rs.html#60-62">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>&#x2212;</span>]</button></span></div><pre class="rust item-decl"><code>pub fn spawn&lt;F&gt;(func: F)<div class="where">where
F: <a class="trait" href="https://doc.rust-lang.org/1.76.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() + <a class="trait" href="https://doc.rust-lang.org/1.76.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> + 'static,</div></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Puts the task into the Rayon threadpools job queue 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 CPUs 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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