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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="Creates a `SmallVec` containing the arguments."><title>smallvec in smallvec - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="smallvec" data-themes="" data-resource-suffix="" data-rustdoc-version="1.80.0 (051478957 2024-07-21)" data-channel="1.80.0" data-search-js="search-d52510db62a78183.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../static.files/storage-118b08c4c78b968e.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-20a3ad099b048cf2.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-df360f571f6edeae.css"></noscript><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 macro"><!--[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" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../smallvec/index.html">smallvec</a><span class="version">1.13.2</span></h2></div><div class="sidebar-elems"></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1>Macro <a href="index.html">smallvec</a>::<wbr><a class="macro" href="#">smallvec</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><a class="src" href="../src/smallvec/lib.rs.html#182-199">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>&#x2212;</span>]</button></span></div><pre class="rust item-decl"><span class="macro">macro_rules!</span> smallvec {
(@one <span class="macro-nonterminal">$x</span>:expr) =&gt; { ... };
(<span class="macro-nonterminal">$elem</span>:expr; <span class="macro-nonterminal">$n</span>:expr) =&gt; { ... };
($(<span class="macro-nonterminal">$x</span>:expr),<span class="kw-2">*</span>$(,)<span class="kw-2">*</span>) =&gt; { ... };
}</pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Creates a <a href="struct.SmallVec.html" title="struct smallvec::SmallVec"><code>SmallVec</code></a> containing the arguments.</p>
<p><code>smallvec!</code> allows <code>SmallVec</code>s to be defined with the same syntax as array expressions.
There are two forms of this macro:</p>
<ul>
<li>Create a <a href="struct.SmallVec.html" title="struct smallvec::SmallVec"><code>SmallVec</code></a> containing a given list of elements:</li>
</ul>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>v: SmallVec&lt;[<span class="kw">_</span>; <span class="number">128</span>]&gt; = <span class="macro">smallvec!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>];
<span class="macro">assert_eq!</span>(v[<span class="number">0</span>], <span class="number">1</span>);
<span class="macro">assert_eq!</span>(v[<span class="number">1</span>], <span class="number">2</span>);
<span class="macro">assert_eq!</span>(v[<span class="number">2</span>], <span class="number">3</span>);</code></pre></div>
<ul>
<li>Create a <a href="struct.SmallVec.html" title="struct smallvec::SmallVec"><code>SmallVec</code></a> from a given element and size:</li>
</ul>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>v: SmallVec&lt;[<span class="kw">_</span>; <span class="number">0x8000</span>]&gt; = <span class="macro">smallvec!</span>[<span class="number">1</span>; <span class="number">3</span>];
<span class="macro">assert_eq!</span>(v, SmallVec::from_buf([<span class="number">1</span>, <span class="number">1</span>, <span class="number">1</span>]));</code></pre></div>
<p>Note that unlike array expressions this syntax supports all elements
which implement <a href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html" title="trait core::clone::Clone"><code>Clone</code></a> and the number of elements doesnt have to be
a constant.</p>
<p>This will use <code>clone</code> to duplicate an expression, so one should be careful
using this with types having a nonstandard <code>Clone</code> implementation. For
example, <code>smallvec![Rc::new(1); 5]</code> will create a vector of five references
to the same boxed integer value, not five references pointing to independently
boxed integers.</p>
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