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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="A primitive that provides lazy one-time initialization."><title>Once in spin::once - 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-b0742ba02757f159.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="spin" data-themes="" data-resource-suffix="" data-rustdoc-version="1.83.0 (90b35a623 2024-11-26)" data-channel="1.83.0" data-search-js="search-f0d225181b97f9a4.js" data-settings-js="settings-805db61a62df4bd2.js" ><script src="../../static.files/storage-1d39b6787ed640ff.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../static.files/main-f070b9041d14864c.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-0111fcff984fae8f.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 struct"><!--[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="../../spin/index.html">spin</a><span class="version">0.9.8</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">Once</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#examples" title="Examples">Examples</a></li></ul><h3><a href="#implementations">Associated Constants</a></h3><ul class="block associatedconstant"><li><a href="#associatedconstant.INIT" title="INIT">INIT</a></li></ul><h3><a href="#implementations">Methods</a></h3><ul class="block method"><li><a href="#method.as_mut_ptr" title="as_mut_ptr">as_mut_ptr</a></li><li><a href="#method.call_once" title="call_once">call_once</a></li><li><a href="#method.get" title="get">get</a></li><li><a href="#method.get_mut" title="get_mut">get_mut</a></li><li><a href="#method.get_mut_unchecked" title="get_mut_unchecked">get_mut_unchecked</a></li><li><a href="#method.get_unchecked" title="get_unchecked">get_unchecked</a></li><li><a href="#method.initialized" title="initialized">initialized</a></li><li><a href="#method.into_inner_unchecked" title="into_inner_unchecked">into_inner_unchecked</a></li><li><a href="#method.is_completed" title="is_completed">is_completed</a></li><li><a href="#method.new" title="new">new</a></li><li><a href="#method.poll" title="poll">poll</a></li><li><a href="#method.try_call_once" title="try_call_once">try_call_once</a></li><li><a href="#method.try_into_inner" title="try_into_inner">try_into_inner</a></li><li><a href="#method.wait" title="wait">wait</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block trait-implementation"><li><a href="#impl-Debug-for-Once%3CT,+R%3E" title="Debug">Debug</a></li><li><a href="#impl-Default-for-Once%3CT,+R%3E" title="Default">Default</a></li><li><a href="#impl-Drop-for-Once%3CT,+R%3E" title="Drop">Drop</a></li><li><a href="#impl-From%3CT%3E-for-Once%3CT,+R%3E" title="From<T>">From<T></a></li><li><a href="#impl-Send-for-Once%3CT,+R%3E" title="Send">Send</a></li><li><a href="#impl-Sync-for-Once%3CT,+R%3E" title="Sync">Sync</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block synthetic-implementation"><li><a href="#impl-Freeze-for-Once%3CT,+R%3E" title="!Freeze">!Freeze</a></li><li><a href="#impl-RefUnwindSafe-for-Once%3CT,+R%3E" title="!RefUnwindSafe">!RefUnwindSafe</a></li><li><a href="#impl-Unpin-for-Once%3CT,+R%3E" title="Unpin">Unpin</a></li><li><a href="#impl-UnwindSafe-for-Once%3CT,+R%3E" title="UnwindSafe">UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block blanket-implementation"><li><a href="#impl-Any-for-T" title="Any">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-T" title="Borrow<T>">Borrow<T></a></li><li><a href="#impl-BorrowMut%3CT%3E-for-T" title="BorrowMut<T>">BorrowMut<T></a></li><li><a href="#impl-From%3C!%3E-for-T" title="From<!>">From<!></a></li><li><a href="#impl-From%3CT%3E-for-T" title="From<T>">From<T></a></li><li><a href="#impl-Into%3CU%3E-for-T" title="Into<U>">Into<U></a></li><li><a href="#impl-TryFrom%3CU%3E-for-T" title="TryFrom<U>">TryFrom<U></a></li><li><a href="#impl-TryInto%3CU%3E-for-T" title="TryInto<U>">TryInto<U></a></li></ul></section><div id="rustdoc-modnav"><h2><a href="index.html">In spin::<wbr>once</a></h2></div></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"><span class="rustdoc-breadcrumbs"><a href="../index.html">spin</a>::<wbr><a href="index.html">once</a></span><h1>Struct <span class="struct">Once</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../../src/spin/once.rs.html#28-32">source</a> </span></div><pre class="rust item-decl"><code>pub struct Once<T = <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.unit.html">()</a>, R = <a class="struct" href="../relax/struct.Spin.html" title="struct spin::relax::Spin">Spin</a>> { <span class="comment">/* private fields */</span> }</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>A primitive that provides lazy one-time initialization.</p>
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<p>Unlike its <code>std::sync</code> equivalent, this is generalized such that the closure returns a
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value to be stored by the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> (<code>std::sync::Once</code> can be trivially emulated with
|
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<code>Once</code>).</p>
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<p>Because <a href="struct.Once.html#method.new" title="associated function spin::once::Once::new"><code>Once::new</code></a> is <code>const</code>, this primitive may be used to safely initialize statics.</p>
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<h2 id="examples"><a class="doc-anchor" href="#examples">§</a>Examples</h2>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>spin;
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<span class="kw">static </span>START: spin::Once = spin::Once::new();
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START.call_once(|| {
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<span class="comment">// run initialization here
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</span>});</code></pre></div>
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</div></details><h2 id="implementations" class="section-header">Implementations<a href="#implementations" class="anchor">§</a></h2><div id="implementations-list"><details class="toggle implementors-toggle" open><summary><section id="impl-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#133-338">source</a><a href="#impl-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T, R: <a class="trait" href="../relax/trait.RelaxStrategy.html" title="trait spin::relax::RelaxStrategy">RelaxStrategy</a>> <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.call_once" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#168-173">source</a><h4 class="code-header">pub fn <a href="#method.call_once" class="fn">call_once</a><F: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -> T>(&self, f: F) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a></h4></section></summary><div class="docblock"><p>Performs an initialization routine once and only once. The given closure
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will be executed if this is the first time <code>call_once</code> has been called,
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and otherwise the routine will <em>not</em> be invoked.</p>
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<p>This method will block the calling thread if another initialization
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routine is currently running.</p>
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<p>When this function returns, it is guaranteed that some initialization
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has run and completed (it may not be the closure specified). The
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returned pointer will point to the result from the closure that was
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run.</p>
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<h5 id="panics"><a class="doc-anchor" href="#panics">§</a>Panics</h5>
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<p>This function will panic if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> previously panicked while attempting
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to initialize. This is similar to the poisoning behaviour of <code>std::sync</code>’s
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primitives.</p>
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<h5 id="examples-1"><a class="doc-anchor" href="#examples-1">§</a>Examples</h5>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>spin;
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<span class="kw">static </span>INIT: spin::Once<usize> = spin::Once::new();
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<span class="kw">fn </span>get_cached_val() -> usize {
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<span class="kw-2">*</span>INIT.call_once(expensive_computation)
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}
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<span class="kw">fn </span>expensive_computation() -> usize {
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<span class="comment">// ...
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</span>}</code></pre></div>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.try_call_once" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#208-214">source</a><h4 class="code-header">pub fn <a href="#method.try_call_once" class="fn">try_call_once</a><F: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, E>, E>(
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&self,
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f: F,
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) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a>, E></h4></section></summary><div class="docblock"><p>This method is similar to <code>call_once</code>, but allows the given closure to
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fail, and lets the <code>Once</code> in a uninitialized state if it does.</p>
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<p>This method will block the calling thread if another initialization
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routine is currently running.</p>
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<p>When this function returns without error, it is guaranteed that some
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initialization has run and completed (it may not be the closure
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specified). The returned reference will point to the result from the
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closure that was run.</p>
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<h5 id="panics-1"><a class="doc-anchor" href="#panics-1">§</a>Panics</h5>
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<p>This function will panic if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> previously panicked while attempting
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to initialize. This is similar to the poisoning behaviour of <code>std::sync</code>’s
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primitives.</p>
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<h5 id="examples-2"><a class="doc-anchor" href="#examples-2">§</a>Examples</h5>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>spin;
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<span class="kw">static </span>INIT: spin::Once<usize> = spin::Once::new();
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<span class="kw">fn </span>get_cached_val() -> <span class="prelude-ty">Result</span><usize, String> {
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INIT.try_call_once(expensive_fallible_computation).map(|x| <span class="kw-2">*</span>x)
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}
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<span class="kw">fn </span>expensive_fallible_computation() -> <span class="prelude-ty">Result</span><usize, String> {
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<span class="comment">// ...
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</span>}</code></pre></div>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.wait" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#306-313">source</a><h4 class="code-header">pub fn <a href="#method.wait" class="fn">wait</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a></h4></section></summary><div class="docblock"><p>Spins until the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> contains a value.</p>
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<p>Note that in releases prior to <code>0.7</code>, this function had the behaviour of <a href="struct.Once.html#method.poll" title="method spin::once::Once::poll"><code>Once::poll</code></a>.</p>
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<h5 id="panics-2"><a class="doc-anchor" href="#panics-2">§</a>Panics</h5>
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<p>This function will panic if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> previously panicked while attempting
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to initialize. This is similar to the poisoning behaviour of <code>std::sync</code>’s
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primitives.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.poll" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#325-337">source</a><h4 class="code-header">pub fn <a href="#method.poll" class="fn">poll</a>(&self) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a><<a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a>></h4></section></summary><div class="docblock"><p>Like <a href="struct.Once.html#method.get" title="method spin::once::Once::get"><code>Once::get</code></a>, but will spin if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> is in the process of being
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initialized. If initialization has not even begun, <code>None</code> will be returned.</p>
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<p>Note that in releases prior to <code>0.7</code>, this function was named <code>wait</code>.</p>
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<h5 id="panics-3"><a class="doc-anchor" href="#panics-3">§</a>Panics</h5>
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<p>This function will panic if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> previously panicked while attempting
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to initialize. This is similar to the poisoning behaviour of <code>std::sync</code>’s
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primitives.</p>
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</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Once%3CT,+R%3E-1" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#340-489">source</a><a href="#impl-Once%3CT,+R%3E-1" class="anchor">§</a><h3 class="code-header">impl<T, R> <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></summary><div class="impl-items"><details class="toggle" open><summary><section id="associatedconstant.INIT" class="associatedconstant"><a class="src rightside" href="../../src/spin/once.rs.html#343-347">source</a><h4 class="code-header">pub const <a href="#associatedconstant.INIT" class="constant">INIT</a>: Self = _</h4></section></summary><div class="docblock"><p>Initialization constant of <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a>.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.new" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#350-352">source</a><h4 class="code-header">pub const fn <a href="#method.new" class="fn">new</a>() -> Self</h4></section></summary><div class="docblock"><p>Creates a new <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a>.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.initialized" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#355-361">source</a><h4 class="code-header">pub const fn <a href="#method.initialized" class="fn">initialized</a>(data: T) -> Self</h4></section></summary><div class="docblock"><p>Creates a new initialized <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a>.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.as_mut_ptr" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#368-372">source</a><h4 class="code-header">pub fn <a href="#method.as_mut_ptr" class="fn">as_mut_ptr</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.pointer.html">*mut T</a></h4></section></summary><div class="docblock"><p>Retrieve a pointer to the inner data.</p>
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<p>While this method itself is safe, accessing the pointer before the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> has been
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initialized is UB, unless this method has already been written to from a pointer coming
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from this method.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.get" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#399-406">source</a><h4 class="code-header">pub fn <a href="#method.get" class="fn">get</a>(&self) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a><<a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a>></h4></section></summary><div class="docblock"><p>Returns a reference to the inner value if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> has been initialized.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.get_unchecked" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#416-423">source</a><h4 class="code-header">pub unsafe fn <a href="#method.get_unchecked" class="fn">get_unchecked</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a></h4></section></summary><div class="docblock"><p>Returns a reference to the inner value on the unchecked assumption that the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> has been initialized.</p>
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<h5 id="safety"><a class="doc-anchor" href="#safety">§</a>Safety</h5>
|
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<p>This is <em>extremely</em> unsafe if the <code>Once</code> has not already been initialized because a reference to uninitialized
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memory will be returned, immediately triggering undefined behaviour (even if the reference goes unused).
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However, this can be useful in some instances for exposing the <code>Once</code> to FFI or when the overhead of atomically
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checking initialization is unacceptable and the <code>Once</code> has already been initialized.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.get_mut" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#429-434">source</a><h4 class="code-header">pub fn <a href="#method.get_mut" class="fn">get_mut</a>(&mut self) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a><<a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&mut T</a>></h4></section></summary><div class="docblock"><p>Returns a mutable reference to the inner value if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> has been initialized.</p>
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<p>Because this method requires a mutable reference to the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a>, no synchronization
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overhead is required to access the inner value. In effect, it is zero-cost.</p>
|
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</div></details><details class="toggle method-toggle" open><summary><section id="method.get_mut_unchecked" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#444-451">source</a><h4 class="code-header">pub unsafe fn <a href="#method.get_mut_unchecked" class="fn">get_mut_unchecked</a>(&mut self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&mut T</a></h4></section></summary><div class="docblock"><p>Returns a mutable reference to the inner value</p>
|
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<h5 id="safety-1"><a class="doc-anchor" href="#safety-1">§</a>Safety</h5>
|
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<p>This is <em>extremely</em> unsafe if the <code>Once</code> has not already been initialized because a reference to uninitialized
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||
memory will be returned, immediately triggering undefined behaviour (even if the reference goes unused).
|
||
However, this can be useful in some instances for exposing the <code>Once</code> to FFI or when the overhead of atomically
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||
checking initialization is unacceptable and the <code>Once</code> has already been initialized.</p>
|
||
</div></details><details class="toggle method-toggle" open><summary><section id="method.try_into_inner" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#457-462">source</a><h4 class="code-header">pub fn <a href="#method.try_into_inner" class="fn">try_into_inner</a>(self) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a><T></h4></section></summary><div class="docblock"><p>Returns a the inner value if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> has been initialized.</p>
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<p>Because this method requires ownership of the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a>, no synchronization overhead
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||
is required to access the inner value. In effect, it is zero-cost.</p>
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</div></details><details class="toggle method-toggle" open><summary><section id="method.into_inner_unchecked" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#471-478">source</a><h4 class="code-header">pub unsafe fn <a href="#method.into_inner_unchecked" class="fn">into_inner_unchecked</a>(self) -> T</h4></section></summary><div class="docblock"><p>Returns a the inner value if the <a href="struct.Once.html" title="struct spin::once::Once"><code>Once</code></a> has been initialized.</p>
|
||
<h5 id="safety-2"><a class="doc-anchor" href="#safety-2">§</a>Safety</h5>
|
||
<p>This is <em>extremely</em> unsafe if the <code>Once</code> has not already been initialized because a reference to uninitialized
|
||
memory will be returned, immediately triggering undefined behaviour (even if the reference goes unused)
|
||
This can be useful, if <code>Once</code> has already been initialized, and you want to bypass an
|
||
option check.</p>
|
||
</div></details><details class="toggle method-toggle" open><summary><section id="method.is_completed" class="method"><a class="src rightside" href="../../src/spin/once.rs.html#485-488">source</a><h4 class="code-header">pub fn <a href="#method.is_completed" class="fn">is_completed</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.bool.html">bool</a></h4></section></summary><div class="docblock"><p>Checks whether the value has been initialized.</p>
|
||
<p>This is done using <a href="https://doc.rust-lang.org/1.83.0/core/sync/atomic/enum.Ordering.html#variant.Acquire" title="variant core::sync::atomic::Ordering::Acquire"><code>Acquire</code></a> ordering, and
|
||
therefore it is safe to access the value directly via
|
||
<a href="struct.Once.html#method.get_unchecked" title="method spin::once::Once::get_unchecked"><code>get_unchecked</code></a> if this returns true.</p>
|
||
</div></details></div></details></div><h2 id="trait-implementations" class="section-header">Trait Implementations<a href="#trait-implementations" class="anchor">§</a></h2><div id="trait-implementations-list"><details class="toggle implementors-toggle" open><summary><section id="impl-Debug-for-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#40-49">source</a><a href="#impl-Debug-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a>, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.fmt" class="method trait-impl"><a class="src rightside" href="../../src/spin/once.rs.html#41-48">source</a><a href="#method.fmt" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/fmt/trait.Debug.html#tymethod.fmt" class="fn">fmt</a>(&self, f: &mut <a class="struct" href="https://doc.rust-lang.org/1.83.0/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a><'_>) -> <a class="type" href="https://doc.rust-lang.org/1.83.0/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></h4></section></summary><div class='docblock'>Formats the value using the given formatter. <a href="https://doc.rust-lang.org/1.83.0/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Default-for-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#34-38">source</a><a href="#impl-Default-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/default/trait.Default.html" title="trait core::default::Default">Default</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.default" class="method trait-impl"><a class="src rightside" href="../../src/spin/once.rs.html#35-37">source</a><a href="#method.default" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/default/trait.Default.html#tymethod.default" class="fn">default</a>() -> Self</h4></section></summary><div class='docblock'>Returns the “default value” for a type. <a href="https://doc.rust-lang.org/1.83.0/core/default/trait.Default.html#tymethod.default">Read more</a></div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Drop-for-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#497-507">source</a><a href="#impl-Drop-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/ops/drop/trait.Drop.html" title="trait core::ops::drop::Drop">Drop</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.drop" class="method trait-impl"><a class="src rightside" href="../../src/spin/once.rs.html#498-506">source</a><a href="#method.drop" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/ops/drop/trait.Drop.html#tymethod.drop" class="fn">drop</a>(&mut self)</h4></section></summary><div class='docblock'>Executes the destructor for this type. <a href="https://doc.rust-lang.org/1.83.0/core/ops/drop/trait.Drop.html#tymethod.drop">Read more</a></div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-From%3CT%3E-for-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#491-495">source</a><a href="#impl-From%3CT%3E-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html" title="trait core::convert::From">From</a><T> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.from" class="method trait-impl"><a class="src rightside" href="../../src/spin/once.rs.html#492-494">source</a><a href="#method.from" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(data: T) -> Self</h4></section></summary><div class='docblock'>Converts to this type from the input type.</div></details></div></details><section id="impl-Send-for-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#54">source</a><a href="#impl-Send-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a>, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section><section id="impl-Sync-for-Once%3CT,+R%3E" class="impl"><a class="src rightside" href="../../src/spin/once.rs.html#53">source</a><a href="#impl-Sync-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> + <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a>, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section></div><h2 id="synthetic-implementations" class="section-header">Auto Trait Implementations<a href="#synthetic-implementations" class="anchor">§</a></h2><div id="synthetic-implementations-list"><section id="impl-Freeze-for-Once%3CT,+R%3E" class="impl"><a href="#impl-Freeze-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T = <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.unit.html">()</a>, R = <a class="struct" href="../relax/struct.Spin.html" title="struct spin::relax::Spin">Spin</a>> !<a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Freeze.html" title="trait core::marker::Freeze">Freeze</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section><section id="impl-RefUnwindSafe-for-Once%3CT,+R%3E" class="impl"><a href="#impl-RefUnwindSafe-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T = <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.unit.html">()</a>, R = <a class="struct" href="../relax/struct.Spin.html" title="struct spin::relax::Spin">Spin</a>> !<a class="trait" href="https://doc.rust-lang.org/1.83.0/core/panic/unwind_safe/trait.RefUnwindSafe.html" title="trait core::panic::unwind_safe::RefUnwindSafe">RefUnwindSafe</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R></h3></section><section id="impl-Unpin-for-Once%3CT,+R%3E" class="impl"><a href="#impl-Unpin-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R><div class="where">where
|
||
R: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a>,
|
||
T: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a>,</div></h3></section><section id="impl-UnwindSafe-for-Once%3CT,+R%3E" class="impl"><a href="#impl-UnwindSafe-for-Once%3CT,+R%3E" class="anchor">§</a><h3 class="code-header">impl<T, R> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a> for <a class="struct" href="struct.Once.html" title="struct spin::once::Once">Once</a><T, R><div class="where">where
|
||
R: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a>,
|
||
T: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a>,</div></h3></section></div><h2 id="blanket-implementations" class="section-header">Blanket Implementations<a href="#blanket-implementations" class="anchor">§</a></h2><div id="blanket-implementations-list"><details class="toggle implementors-toggle"><summary><section id="impl-Any-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/any.rs.html#138">source</a><a href="#impl-Any-for-T" class="anchor">§</a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/any/trait.Any.html" title="trait core::any::Any">Any</a> for T<div class="where">where
|
||
T: 'static + ?<a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.type_id" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/any.rs.html#139">source</a><a href="#method.type_id" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/any/trait.Any.html#tymethod.type_id" class="fn">type_id</a>(&self) -> <a class="struct" href="https://doc.rust-lang.org/1.83.0/core/any/struct.TypeId.html" title="struct core::any::TypeId">TypeId</a></h4></section></summary><div class='docblock'>Gets the <code>TypeId</code> of <code>self</code>. <a href="https://doc.rust-lang.org/1.83.0/core/any/trait.Any.html#tymethod.type_id">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-Borrow%3CT%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/borrow.rs.html#209">source</a><a href="#impl-Borrow%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a><T> for T<div class="where">where
|
||
T: ?<a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.borrow" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/borrow.rs.html#211">source</a><a href="#method.borrow" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/borrow/trait.Borrow.html#tymethod.borrow" class="fn">borrow</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&T</a></h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a href="https://doc.rust-lang.org/1.83.0/core/borrow/trait.Borrow.html#tymethod.borrow">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-BorrowMut%3CT%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/borrow.rs.html#217">source</a><a href="#impl-BorrowMut%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/borrow/trait.BorrowMut.html" title="trait core::borrow::BorrowMut">BorrowMut</a><T> for T<div class="where">where
|
||
T: ?<a class="trait" href="https://doc.rust-lang.org/1.83.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.borrow_mut" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/borrow.rs.html#218">source</a><a href="#method.borrow_mut" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut" class="fn">borrow_mut</a>(&mut self) -> <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.reference.html">&mut T</a></h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a href="https://doc.rust-lang.org/1.83.0/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-From%3C!%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#782">source</a><a href="#impl-From%3C!%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html" title="trait core::convert::From">From</a><<a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.never.html">!</a>> for T</h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.from-2" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#783">source</a><a href="#method.from-2" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(t: <a class="primitive" href="https://doc.rust-lang.org/1.83.0/core/primitive.never.html">!</a>) -> T</h4></section></summary><div class='docblock'>Converts to this type from the input type.</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-From%3CT%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#765">source</a><a href="#impl-From%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html" title="trait core::convert::From">From</a><T> for T</h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.from-1" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#768">source</a><a href="#method.from-1" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(t: T) -> T</h4></section></summary><div class="docblock"><p>Returns the argument unchanged.</p>
|
||
</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-Into%3CU%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#748-750">source</a><a href="#impl-Into%3CU%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a><U> for T<div class="where">where
|
||
U: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html" title="trait core::convert::From">From</a><T>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.into" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#758">source</a><a href="#method.into" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.Into.html#tymethod.into" class="fn">into</a>(self) -> U</h4></section></summary><div class="docblock"><p>Calls <code>U::from(self)</code>.</p>
|
||
<p>That is, this conversion is whatever the implementation of
|
||
<code><a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.From.html" title="trait core::convert::From">From</a><T> for U</code> chooses to do.</p>
|
||
</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-TryFrom%3CU%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#805-807">source</a><a href="#impl-TryFrom%3CU%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><U> for T<div class="where">where
|
||
U: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a><T>,</div></h3></section></summary><div class="impl-items"><details class="toggle" open><summary><section id="associatedtype.Error-1" class="associatedtype trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#809">source</a><a href="#associatedtype.Error-1" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/convert/enum.Infallible.html" title="enum core::convert::Infallible">Infallible</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="toggle method-toggle" open><summary><section id="method.try_from" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#812">source</a><a href="#method.try_from" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html#tymethod.try_from" class="fn">try_from</a>(value: U) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, <T as <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><U>>::<a class="associatedtype" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-TryInto%3CU%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#790-792">source</a><a href="#impl-TryInto%3CU%3E-for-T" class="anchor">§</a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryInto.html" title="trait core::convert::TryInto">TryInto</a><U> for T<div class="where">where
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U: <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>,</div></h3></section></summary><div class="impl-items"><details class="toggle" open><summary><section id="associatedtype.Error" class="associatedtype trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#794">source</a><a href="#associatedtype.Error" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryInto.html#associatedtype.Error" class="associatedtype">Error</a> = <U as <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>>::<a class="associatedtype" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="toggle method-toggle" open><summary><section id="method.try_into" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.83.0/src/core/convert/mod.rs.html#797">source</a><a href="#method.try_into" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryInto.html#tymethod.try_into" class="fn">try_into</a>(self) -> <a class="enum" href="https://doc.rust-lang.org/1.83.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a><U, <U as <a class="trait" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>>::<a class="associatedtype" href="https://doc.rust-lang.org/1.83.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details></div></section></div></main></body></html> |