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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 memory location that can be written to at most once."><title>OnceCell in async_lock - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.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-9960930a.css"><link rel="stylesheet" href="../static.files/rustdoc-42caa33d.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="async_lock" data-themes="" 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alt=""></a></nav><nav class="sidebar"><div class="sidebar-crate"><a class="logo-container" href="../async_lock/index.html"><img src="https://raw.githubusercontent.com/smol-rs/smol/master/assets/images/logo_fullsize_transparent.png" alt="logo"></a><h2><a href="../async_lock/index.html">async_<wbr>lock</a><span class="version">3.4.0</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">Once<wbr>Cell</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">Methods</a></h3><ul class="block method"><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_or_init" title="get_or_init">get_or_init</a></li><li><a href="#method.get_or_init_blocking" title="get_or_init_blocking">get_or_init_blocking</a></li><li><a href="#method.get_or_try_init" title="get_or_try_init">get_or_try_init</a></li><li><a href="#method.get_or_try_init_blocking" title="get_or_try_init_blocking">get_or_try_init_blocking</a></li><li><a href="#method.get_unchecked" title="get_unchecked">get_unchecked</a></li><li><a href="#method.into_inner" title="into_inner">into_inner</a></li><li><a href="#method.is_initialized" title="is_initialized">is_initialized</a></li><li><a href="#method.new" title="new">new</a></li><li><a href="#method.set" title="set">set</a></li><li><a href="#method.set_blocking" title="set_blocking">set_blocking</a></li><li><a href="#method.take" title="take">take</a></li><li><a href="#method.wait" title="wait">wait</a></li><li><a href="#method.wait_blocking" title="wait_blocking">wait_blocking</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block trait-implementation"><li><a href="#impl-Debug-for-OnceCell%3CT%3E" title="Debug">Debug</a></li><li><a href="#impl-Default-for-OnceCell%3CT%3E" title="Default">Default</a></li><li><a href="#impl-Drop-for-OnceCell%3CT%3E" title="Drop">Drop</a></li><li><a href="#impl-From%3CT%3E-for-OnceCell%3CT%3E" title="From&#60;T&#62;">From&#60;T&#62;</a></li><li><a href="#impl-Send-for-OnceCell%3CT%3E" title="Send">Send</a></li><li><a href="#impl-Sync-for-OnceCell%3CT%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-OnceCell%3CT%3E" title="!Freeze">!Freeze</a></li><li><a href="#impl-RefUnwindSafe-for-OnceCell%3CT%3E" title="!RefUnwindSafe">!RefUnwindSafe</a></li><li><a href="#impl-Unpin-for-OnceCell%3CT%3E" title="Unpin">Unpin</a></li><li><a href="#impl-UnwindSafe-for-OnceCell%3CT%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&#60;T&#62;">Borrow&#60;T&#62;</a></li><li><a href="#impl-BorrowMut%3CT%3E-for-T" title="BorrowMut&#60;T&#62;">BorrowMut&#60;T&#62;</a></li><li><a href="#impl-From%3C!%3E-for-T" title="From&#60;!&#62;">From&#60;!&#62;</a></li><li><a href="#impl-From%3CT%3E-for-T" title="From&#60;T&#62;">From&#60;T&#62;</a></li><li><a href="#impl-Into%3CU%3E-for-T" title="Into&#60;U&#62;">Into&#60;U&#62;</a></li><li><a href="#impl-TryFrom%3CU%3E-for-T" title="TryFrom&#60;U&#62;">TryFrom&#60;U&#62;</a></li><li><a href="#impl-TryInto%3CU%3E-for-T" title="TryInto&#60;U&#62;">TryInto&#60;U&#62;</a></li></ul></section><div id="rustdoc-modnav"><h2 class="in-crate"><a href="index.html">In crate async_<wbr>lock</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">async_lock</a></span><h1>Struct <span class="struct">OnceCell</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/async_lock/once_cell.rs.html#92-108">Source</a> </span></div><pre class="rust item-decl"><code>pub struct OnceCell&lt;T&gt; { <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 memory location that can be written to at most once.</p>
<p>A <code>OnceCell</code> can be used to store a single value, and only once. However,
once the value is stored, it can be accessed directly through a reference
instead of needing an RAII guard like <code>Mutex</code> or <code>RwLock</code>.</p>
<h2 id="examples"><a class="doc-anchor" href="#examples">§</a>Examples</h2>
<p>This structure is useful for a variety of patterns, most notably for one-time
initialization.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">async fn </span>very_expensive_initialization() -&gt; Foobar {
<span class="comment">// Imagine this is very expensive to initialize,
// for instance, it requires a network request or
// a database call.
</span>}
<span class="kw">struct </span>LazyFoobar {
inner: OnceCell&lt;Foobar&gt;,
}
<span class="kw">impl </span>LazyFoobar {
<span class="kw">fn </span>new() -&gt; <span class="self">Self </span>{
<span class="self">Self </span>{
inner: OnceCell::new(),
}
}
<span class="kw">async fn </span>load(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw-2">&amp;</span>Foobar {
<span class="self">self</span>.inner.get_or_init(|| <span class="kw">async </span>{
very_expensive_initialization().<span class="kw">await
</span>}).<span class="kw">await
</span>}
}</code></pre></div>
</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-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#113-721">Source</a><a href="#impl-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.new" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#114-134">Source</a><h4 class="code-header">pub const fn <a href="#method.new" class="fn">new</a>() -&gt; Self</h4></section></summary><div class="docblock"><p>Create a new, uninitialized <code>OnceCell</code>.</p>
<h5 id="example"><a class="doc-anchor" href="#example">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.is_initialized" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#154-156">Source</a><h4 class="code-header">pub fn <a href="#method.is_initialized" class="fn">is_initialized</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.bool.html">bool</a></h4></section></summary><div class="docblock"><p>Tell whether or not the cell is initialized.</p>
<p>This may not always be accurate. For instance, it is possible for
another thread to initialize the cell between the time when this
function is called and the time when the result is actually used.</p>
<h5 id="example-1"><a class="doc-anchor" href="#example-1">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="macro">assert!</span>(!cell.is_initialized());
cell.set(<span class="number">1</span>).<span class="kw">await</span>;
<span class="macro">assert!</span>(cell.is_initialized());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#173-181">Source</a><h4 class="code-header">pub fn <a href="#method.get" class="fn">get</a>(&amp;self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a>&gt;</h4></section></summary><div class="docblock"><p>Get a reference to the inner value, or <code>None</code> if the value
is not yet initialized.</p>
<h5 id="example-2"><a class="doc-anchor" href="#example-2">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="macro">assert!</span>(cell.get().is_none());
cell.set(<span class="number">1</span>).<span class="kw">await</span>;
<span class="macro">assert_eq!</span>(cell.get(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">1</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get_mut" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#203-213">Source</a><h4 class="code-header">pub fn <a href="#method.get_mut" class="fn">get_mut</a>(&amp;mut self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;mut T</a>&gt;</h4></section></summary><div class="docblock"><p>Get a mutable reference to the inner value, or <code>None</code> if the value
is not yet initialized.</p>
<p>This function is useful for initializing the value inside the cell
when we still have a mutable reference to the cell.</p>
<h5 id="example-3"><a class="doc-anchor" href="#example-3">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span><span class="kw-2">mut </span>cell = OnceCell::new();
<span class="macro">assert!</span>(cell.get_mut().is_none());
cell.set(<span class="number">1</span>).<span class="kw">await</span>;
<span class="macro">assert_eq!</span>(cell.get_mut(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;mut </span><span class="number">1</span>));
<span class="kw-2">*</span>cell.get_mut().unwrap() = <span class="number">2</span>;
<span class="macro">assert_eq!</span>(cell.get(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">2</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.take" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#230-242">Source</a><h4 class="code-header">pub fn <a href="#method.take" class="fn">take</a>(&amp;mut self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;T&gt;</h4></section></summary><div class="docblock"><p>Take the value out of this <code>OnceCell</code>, moving it back to the uninitialized
state.</p>
<h5 id="example-4"><a class="doc-anchor" href="#example-4">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span><span class="kw-2">mut </span>cell = OnceCell::new();
cell.set(<span class="number">1</span>).<span class="kw">await</span>;
<span class="macro">assert_eq!</span>(cell.take(), <span class="prelude-val">Some</span>(<span class="number">1</span>));
<span class="macro">assert!</span>(!cell.is_initialized());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.into_inner" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#257-259">Source</a><h4 class="code-header">pub fn <a href="#method.into_inner" class="fn">into_inner</a>(self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;T&gt;</h4></section></summary><div class="docblock"><p>Convert this <code>OnceCell</code> into the inner value, if it is initialized.</p>
<h5 id="example-5"><a class="doc-anchor" href="#example-5">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
cell.set(<span class="number">1</span>).<span class="kw">await</span>;
<span class="macro">assert_eq!</span>(cell.into_inner(), <span class="prelude-val">Some</span>(<span class="number">1</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.wait" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#284-304">Source</a><h4 class="code-header">pub async fn <a href="#method.wait" class="fn">wait</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class="docblock"><p>Wait for the cell to be initialized, and then return a reference to the
inner value.</p>
<h5 id="example-6"><a class="doc-anchor" href="#example-6">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">use </span>std::sync::Arc;
<span class="kw">use </span>std::time::Duration;
<span class="kw">use </span>std::thread::{sleep, spawn};
<span class="kw">let </span>cell = Arc::new(OnceCell::new());
<span class="kw">let </span>cell2 = cell.clone();
spawn(<span class="kw">move </span>|| {
sleep(Duration::from_millis(<span class="number">5</span>));
cell2.set_blocking(<span class="number">1</span>);
});
<span class="macro">assert_eq!</span>(cell.wait().<span class="kw">await</span>, <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.wait_blocking" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#337-357">Source</a><h4 class="code-header">pub fn <a href="#method.wait_blocking" class="fn">wait_blocking</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class="docblock"><p>Wait for the cell to be initialized, and then return a reference to the
inner value.</p>
<h5 id="blocking"><a class="doc-anchor" href="#blocking">§</a>Blocking</h5>
<p>In contrast to the <code>wait</code> method, this method blocks the current thread of
execution instead of awaiting.</p>
<p>This method should not be used in an asynchronous context. It is intended
to be used such that a <code>OnceCell</code> can be used in both asynchronous and synchronous contexts.
Calling this method in an asynchronous context may result in deadlocks.</p>
<h5 id="example-7"><a class="doc-anchor" href="#example-7">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">use </span>std::sync::Arc;
<span class="kw">use </span>std::time::Duration;
<span class="kw">use </span>std::thread::{sleep, spawn};
<span class="kw">let </span>cell = Arc::new(OnceCell::new());
<span class="kw">let </span>cell2 = cell.clone();
spawn(<span class="kw">move </span>|| {
sleep(Duration::from_millis(<span class="number">5</span>));
cell2.set_blocking(<span class="number">1</span>);
});
<span class="macro">assert_eq!</span>(cell.wait_blocking(), <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get_or_try_init" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#386-403">Source</a><h4 class="code-header">pub async fn <a href="#method.get_or_try_init" class="fn">get_or_try_init</a>&lt;E, Fut: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/future/future/trait.Future.html" title="trait core::future::future::Future">Future</a>&lt;Output = <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;T, E&gt;&gt;&gt;(
&amp;self,
closure: impl <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -&gt; Fut,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a>, E&gt;</h4></section></summary><div class="docblock"><p>Either get the value or initialize it with the given closure.</p>
<p>The cell will not be initialized if the closure returns an error.</p>
<h5 id="example-8"><a class="doc-anchor" href="#example-8">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="kw">let </span>result = cell.get_or_try_init(|| <span class="kw">async </span>{ <span class="prelude-val">Err</span>(()) }).<span class="kw">await</span>;
<span class="macro">assert!</span>(result.is_err());
<span class="kw">let </span>result = cell.get_or_try_init(|| <span class="kw">async </span>{ <span class="prelude-val">Ok</span>(<span class="number">1</span>) }).<span class="kw">await</span>;
<span class="macro">assert_eq!</span>(result.unwrap(), <span class="kw-2">&amp;</span><span class="number">1</span>);
<span class="kw">let </span>result = cell.get_or_try_init(|| <span class="kw">async </span>{ <span class="prelude-val">Err</span>(()) }).<span class="kw">await</span>;
<span class="macro">assert_eq!</span>(result.unwrap(), <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get_or_try_init_blocking" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#440-460">Source</a><h4 class="code-header">pub fn <a href="#method.get_or_try_init_blocking" class="fn">get_or_try_init_blocking</a>&lt;E&gt;(
&amp;self,
closure: impl <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;T, E&gt;,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a>, E&gt;</h4></section></summary><div class="docblock"><p>Either get the value or initialize it with the given closure.</p>
<p>The cell will not be initialized if the closure returns an error.</p>
<h5 id="blocking-1"><a class="doc-anchor" href="#blocking-1">§</a>Blocking</h5>
<p>In contrast to the <code>get_or_try_init</code> method, this method blocks the current thread of
execution instead of awaiting.</p>
<p>This method should not be used in an asynchronous context. It is intended
to be used such that a <code>OnceCell</code> can be used in both asynchronous and synchronous contexts.
Calling this method in an asynchronous context may result in deadlocks.</p>
<h5 id="example-9"><a class="doc-anchor" href="#example-9">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="kw">let </span>result = cell.get_or_try_init_blocking(|| <span class="prelude-val">Err</span>(()));
<span class="macro">assert!</span>(result.is_err());
<span class="kw">let </span>result = cell.get_or_try_init_blocking(|| <span class="prelude-val">Ok</span>(<span class="number">1</span>));
<span class="macro">assert_eq!</span>(result.unwrap(), <span class="kw-2">&amp;</span><span class="number">1</span>);
<span class="kw">let </span>result = cell.get_or_try_init_blocking(|| <span class="prelude-val">Err</span>(()));
<span class="macro">assert_eq!</span>(result.unwrap(), <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get_or_init" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#478-489">Source</a><h4 class="code-header">pub async fn <a href="#method.get_or_init" class="fn">get_or_init</a>&lt;Fut: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/future/future/trait.Future.html" title="trait core::future::future::Future">Future</a>&lt;Output = T&gt;&gt;(
&amp;self,
closure: impl <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -&gt; Fut,
) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class="docblock"><p>Either get the value or initialize it with the given closure.</p>
<p>Many tasks may call this function, but the value will only be set once
and only one closure will be invoked.</p>
<h5 id="example-10"><a class="doc-anchor" href="#example-10">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="macro">assert_eq!</span>(cell.get_or_init(|| <span class="kw">async </span>{ <span class="number">1 </span>}).<span class="kw">await</span>, <span class="kw-2">&amp;</span><span class="number">1</span>);
<span class="macro">assert_eq!</span>(cell.get_or_init(|| <span class="kw">async </span>{ <span class="number">2 </span>}).<span class="kw">await</span>, <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get_or_init_blocking" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#515-524">Source</a><h4 class="code-header">pub fn <a href="#method.get_or_init_blocking" class="fn">get_or_init_blocking</a>(&amp;self, closure: impl <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -&gt; T + <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a>) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class="docblock"><p>Either get the value or initialize it with the given closure.</p>
<p>Many tasks may call this function, but the value will only be set once
and only one closure will be invoked.</p>
<h5 id="blocking-2"><a class="doc-anchor" href="#blocking-2">§</a>Blocking</h5>
<p>In contrast to the <code>get_or_init</code> method, this method blocks the current thread of
execution instead of awaiting.</p>
<p>This method should not be used in an asynchronous context. It is intended
to be used such that a <code>OnceCell</code> can be used in both asynchronous and synchronous contexts.
Calling this method in an asynchronous context may result in deadlocks.</p>
<h5 id="example-11"><a class="doc-anchor" href="#example-11">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="macro">assert_eq!</span>(cell.get_or_init_blocking(|| <span class="number">1</span>), <span class="kw-2">&amp;</span><span class="number">1</span>);
<span class="macro">assert_eq!</span>(cell.get_or_init_blocking(|| <span class="number">2</span>), <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.set" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#544-555">Source</a><h4 class="code-header">pub async fn <a href="#method.set" class="fn">set</a>(&amp;self, value: T) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a>, T&gt;</h4></section></summary><div class="docblock"><p>Try to set the value of the cell.</p>
<p>If the cell is already initialized, this method returns the original
value back.</p>
<h5 id="example-12"><a class="doc-anchor" href="#example-12">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="macro">assert_eq!</span>(cell.set(<span class="number">1</span>).<span class="kw">await</span>, <span class="prelude-val">Ok</span>(<span class="kw-2">&amp;</span><span class="number">1</span>));
<span class="macro">assert_eq!</span>(cell.get(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">1</span>));
<span class="macro">assert_eq!</span>(cell.set(<span class="number">2</span>).<span class="kw">await</span>, <span class="prelude-val">Err</span>(<span class="number">2</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.set_blocking" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#583-594">Source</a><h4 class="code-header">pub fn <a href="#method.set_blocking" class="fn">set_blocking</a>(&amp;self, value: T) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a>, T&gt;</h4></section></summary><div class="docblock"><p>Try to set the value of the cell.</p>
<p>If the cell is already initialized, this method returns the original
value back.</p>
<h5 id="blocking-3"><a class="doc-anchor" href="#blocking-3">§</a>Blocking</h5>
<p>In contrast to the <code>set</code> method, this method blocks the current thread of
execution instead of awaiting.</p>
<p>This method should not be used in an asynchronous context. It is intended
to be used such that a <code>OnceCell</code> can be used in both asynchronous and synchronous contexts.
Calling this method in an asynchronous context may result in deadlocks.</p>
<h5 id="example-13"><a class="doc-anchor" href="#example-13">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
<span class="macro">assert_eq!</span>(cell.set_blocking(<span class="number">1</span>), <span class="prelude-val">Ok</span>(<span class="kw-2">&amp;</span><span class="number">1</span>));
<span class="macro">assert_eq!</span>(cell.get(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">1</span>));
<span class="macro">assert_eq!</span>(cell.set_blocking(<span class="number">2</span>), <span class="prelude-val">Err</span>(<span class="number">2</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.get_unchecked" class="method"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#717-720">Source</a><h4 class="code-header">pub unsafe fn <a href="#method.get_unchecked" class="fn">get_unchecked</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class="docblock"><p>Get a reference to the inner value.</p>
<h5 id="safety"><a class="doc-anchor" href="#safety">§</a>Safety</h5>
<p>The caller must ensure that the cell is initialized.</p>
<h5 id="example-14"><a class="doc-anchor" href="#example-14">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::new();
cell.set(<span class="number">1</span>).<span class="kw">await</span>;
<span class="comment">// SAFETY: We know that the value is initialized, so it is safe to
// read it.
</span><span class="macro">assert_eq!</span>(<span class="kw">unsafe </span>{ cell.get_unchecked() }, <span class="kw-2">&amp;</span><span class="number">1</span>);</code></pre></div>
</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-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#744-764">Source</a><a href="#impl-Debug-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a>&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</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/async_lock/once_cell.rs.html#745-763">Source</a><a href="#method.fmt" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.84.0/core/fmt/trait.Debug.html#tymethod.fmt" class="fn">fmt</a>(&amp;self, f: &amp;mut <a class="struct" href="https://doc.rust-lang.org/1.84.0/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>&lt;'_&gt;) -&gt; <a class="type" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#778-784">Source</a><a href="#impl-Default-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/default/trait.Default.html" title="trait core::default::Default">Default</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</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/async_lock/once_cell.rs.html#781-783">Source</a><a href="#method.default" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.84.0/core/default/trait.Default.html#tymethod.default" class="fn">default</a>() -&gt; Self</h4></section></summary><div class='docblock'>Returns the “default value” for a type. <a href="https://doc.rust-lang.org/1.84.0/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-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#766-776">Source</a><a href="#impl-Drop-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/ops/drop/trait.Drop.html" title="trait core::ops::drop::Drop">Drop</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</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/async_lock/once_cell.rs.html#767-775">Source</a><a href="#method.drop" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.84.0/core/ops/drop/trait.Drop.html#tymethod.drop" class="fn">drop</a>(&amp;mut self)</h4></section></summary><div class='docblock'>Executes the destructor for this type. <a href="https://doc.rust-lang.org/1.84.0/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-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#723-742">Source</a><a href="#impl-From%3CT%3E-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt; for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</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/async_lock/once_cell.rs.html#734-741">Source</a><a href="#method.from" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.84.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(value: T) -&gt; Self</h4></section></summary><div class="docblock"><p>Create a new, initialized <code>OnceCell</code> from an existing value.</p>
<h5 id="example-15"><a class="doc-anchor" href="#example-15">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>async_lock::OnceCell;
<span class="kw">let </span>cell = OnceCell::from(<span class="number">42</span>);
<span class="macro">assert_eq!</span>(cell.get(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">42</span>));</code></pre></div>
</div></details></div></details><section id="impl-Send-for-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#110">Source</a><a href="#impl-Send-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a>&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</h3></section><section id="impl-Sync-for-OnceCell%3CT%3E" class="impl"><a class="src rightside" href="../src/async_lock/once_cell.rs.html#111">Source</a><a href="#impl-Sync-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> + <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a>&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</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-OnceCell%3CT%3E" class="impl"><a href="#impl-Freeze-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; !<a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Freeze.html" title="trait core::marker::Freeze">Freeze</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</h3></section><section id="impl-RefUnwindSafe-for-OnceCell%3CT%3E" class="impl"><a href="#impl-RefUnwindSafe-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; !<a class="trait" href="https://doc.rust-lang.org/1.84.0/core/panic/unwind_safe/trait.RefUnwindSafe.html" title="trait core::panic::unwind_safe::RefUnwindSafe">RefUnwindSafe</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;</h3></section><section id="impl-Unpin-for-OnceCell%3CT%3E" class="impl"><a href="#impl-Unpin-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;<div class="where">where
T: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a>,</div></h3></section><section id="impl-UnwindSafe-for-OnceCell%3CT%3E" class="impl"><a href="#impl-UnwindSafe-for-OnceCell%3CT%3E" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a> for <a class="struct" href="struct.OnceCell.html" title="struct async_lock::OnceCell">OnceCell</a>&lt;T&gt;<div class="where">where
T: <a class="trait" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/src/core/any.rs.html#138">Source</a><a href="#impl-Any-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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/1.84.0/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/1.84.0/core/any/trait.Any.html#tymethod.type_id" class="fn">type_id</a>(&amp;self) -&gt; <a class="struct" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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/1.84.0/src/core/borrow.rs.html#209">Source</a><a href="#impl-Borrow%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a>&lt;T&gt; for T<div class="where">where
T: ?<a class="trait" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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/1.84.0/core/borrow/trait.Borrow.html#tymethod.borrow" class="fn">borrow</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a href="https://doc.rust-lang.org/1.84.0/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/1.84.0/src/core/borrow.rs.html#217">Source</a><a href="#impl-BorrowMut%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/borrow/trait.BorrowMut.html" title="trait core::borrow::BorrowMut">BorrowMut</a>&lt;T&gt; for T<div class="where">where
T: ?<a class="trait" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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/1.84.0/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut" class="fn">borrow_mut</a>(&amp;mut self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&amp;mut T</a></h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.never.html">!</a>&gt; 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/1.84.0/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/1.84.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(t: <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.never.html">!</a>) -&gt; 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/1.84.0/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&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt; 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/1.84.0/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/1.84.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(t: T) -&gt; 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/1.84.0/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&lt;T, U&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;U&gt; for T<div class="where">where
U: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt;,</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/1.84.0/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/1.84.0/core/convert/trait.Into.html#tymethod.into" class="fn">into</a>(self) -&gt; 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/1.84.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt; 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/1.84.0/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&lt;T, U&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;U&gt; for T<div class="where">where
U: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;T&gt;,</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/1.84.0/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/1.84.0/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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/1.84.0/core/convert/trait.TryFrom.html#tymethod.try_from" class="fn">try_from</a>(value: U) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;T, &lt;T as <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;U&gt;&gt;::<a class="associatedtype" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>&gt;</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/1.84.0/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&lt;T, U&gt; <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryInto.html" title="trait core::convert::TryInto">TryInto</a>&lt;U&gt; for T<div class="where">where
U: <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;T&gt;,</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/1.84.0/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/1.84.0/core/convert/trait.TryInto.html#associatedtype.Error" class="associatedtype">Error</a> = &lt;U as <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;T&gt;&gt;::<a class="associatedtype" href="https://doc.rust-lang.org/1.84.0/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/1.84.0/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/1.84.0/core/convert/trait.TryInto.html#tymethod.try_into" class="fn">try_into</a>(self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;U, &lt;U as <a class="trait" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;T&gt;&gt;::<a class="associatedtype" href="https://doc.rust-lang.org/1.84.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>&gt;</h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details></div></section></div></main></body></html>