| <!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="Counting semaphore performing asynchronous permit acquisition."><meta name="keywords" content="rust, rustlang, rust-lang, Semaphore"><title>Semaphore in tokio::sync - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc 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">☰</button><a class="sidebar-logo" href="../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">Semaphore</a></h2><div class="sidebar-elems"><section><h3><a href="#implementations">Associated Constants</a></h3><ul class="block"><li><a href="#associatedconstant.MAX_PERMITS">MAX_PERMITS</a></li></ul><h3><a href="#implementations">Methods</a></h3><ul class="block"><li><a href="#method.acquire">acquire</a></li><li><a href="#method.acquire_many">acquire_many</a></li><li><a href="#method.acquire_many_owned">acquire_many_owned</a></li><li><a href="#method.acquire_owned">acquire_owned</a></li><li><a href="#method.add_permits">add_permits</a></li><li><a href="#method.available_permits">available_permits</a></li><li><a href="#method.close">close</a></li><li><a href="#method.is_closed">is_closed</a></li><li><a href="#method.new">new</a></li><li><a href="#method.try_acquire">try_acquire</a></li><li><a href="#method.try_acquire_many">try_acquire_many</a></li><li><a href="#method.try_acquire_many_owned">try_acquire_many_owned</a></li><li><a href="#method.try_acquire_owned">try_acquire_owned</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block"><li><a href="#impl-Debug-for-Semaphore">Debug</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block"><li><a href="#impl-RefUnwindSafe-for-Semaphore">!RefUnwindSafe</a></li><li><a href="#impl-Send-for-Semaphore">Send</a></li><li><a href="#impl-Sync-for-Semaphore">Sync</a></li><li><a href="#impl-Unpin-for-Semaphore">Unpin</a></li><li><a href="#impl-UnwindSafe-for-Semaphore">UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block"><li><a href="#impl-Any-for-Semaphore">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-Semaphore">Borrow<T></a></li><li><a href="#impl-BorrowMut%3CT%3E-for-Semaphore">BorrowMut<T></a></li><li><a href="#impl-From%3CT%3E-for-Semaphore">From<T></a></li><li><a href="#impl-Into%3CU%3E-for-Semaphore">Into<U></a></li><li><a href="#impl-TryFrom%3CU%3E-for-Semaphore">TryFrom<U></a></li><li><a href="#impl-TryInto%3CU%3E-for-Semaphore">TryInto<U></a></li></ul></section><h2><a href="index.html">In tokio::sync</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Struct <a href="../index.html">tokio</a>::<wbr><a href="index.html">sync</a>::<wbr><a class="struct" href="#">Semaphore</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../../src/tokio/sync/semaphore.rs.html#79-84">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust struct"><code>pub struct Semaphore { /* private fields */ }</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Counting semaphore performing asynchronous permit acquisition.</p> |
| <p>A semaphore maintains a set of permits. Permits are used to synchronize |
| access to a shared resource. A semaphore differs from a mutex in that it |
| can allow more than one concurrent caller to access the shared resource at a |
| time.</p> |
| <p>When <code>acquire</code> is called and the semaphore has remaining permits, the |
| function immediately returns a permit. However, if no remaining permits are |
| available, <code>acquire</code> (asynchronously) waits until an outstanding permit is |
| dropped. At this point, the freed permit is assigned to the caller.</p> |
| <p>This <code>Semaphore</code> is fair, which means that permits are given out in the order |
| they were requested. This fairness is also applied when <code>acquire_many</code> gets |
| involved, so if a call to <code>acquire_many</code> at the front of the queue requests |
| more permits than currently available, this can prevent a call to <code>acquire</code> |
| from completing, even if the semaphore has enough permits complete the call |
| to <code>acquire</code>.</p> |
| <p>To use the <code>Semaphore</code> in a poll function, you can use the <a href="https://docs.rs/tokio-util/0.6/tokio_util/sync/struct.PollSemaphore.html"><code>PollSemaphore</code></a> |
| utility.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <p>Basic usage:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::{Semaphore, TryAcquireError}; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Semaphore::new(<span class="number">3</span>); |
| |
| <span class="kw">let </span>a_permit = semaphore.acquire().<span class="kw">await</span>.unwrap(); |
| <span class="kw">let </span>two_permits = semaphore.acquire_many(<span class="number">2</span>).<span class="kw">await</span>.unwrap(); |
| |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">0</span>); |
| |
| <span class="kw">let </span>permit_attempt = semaphore.try_acquire(); |
| <span class="macro">assert_eq!</span>(permit_attempt.err(), <span class="prelude-val">Some</span>(TryAcquireError::NoPermits)); |
| }</code></pre></div> |
| <p>Use <a href="struct.Semaphore.html#method.acquire_owned"><code>Semaphore::acquire_owned</code></a> to move permits across tasks:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>tokio::sync::Semaphore; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Arc::new(Semaphore::new(<span class="number">3</span>)); |
| <span class="kw">let </span><span class="kw-2">mut </span>join_handles = Vec::new(); |
| |
| <span class="kw">for _ in </span><span class="number">0</span>..<span class="number">5 </span>{ |
| <span class="kw">let </span>permit = semaphore.clone().acquire_owned().<span class="kw">await</span>.unwrap(); |
| join_handles.push(tokio::spawn(<span class="kw">async move </span>{ |
| <span class="comment">// perform task... |
| // explicitly own `permit` in the task |
| </span>drop(permit); |
| })); |
| } |
| |
| <span class="kw">for </span>handle <span class="kw">in </span>join_handles { |
| handle.<span class="kw">await</span>.unwrap(); |
| } |
| }</code></pre></div> |
| </div></details><h2 id="implementations" class="small-section-header">Implementations<a href="#implementations" class="anchor"></a></h2><div id="implementations-list"><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#127-623">source</a><a href="#impl-Semaphore" class="anchor"></a><h3 class="code-header">impl <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedconstant.MAX_PERMITS" class="associatedconstant has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#131">source</a><h4 class="code-header">pub const <a href="#associatedconstant.MAX_PERMITS" class="constant">MAX_PERMITS</a>: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a> = 2_305_843_009_213_693_951usize</h4></section></summary><div class="docblock"><p>The maximum number of permits which a semaphore can hold. It is <code>usize::MAX >> 3</code>.</p> |
| <p>Exceeding this limit typically results in a panic.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.new" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#137-164">source</a><h4 class="code-header">pub fn <a href="#method.new" class="fnname">new</a>(permits: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -> Self</h4></section></summary><div class="docblock"><p>Creates a new semaphore with the initial number of permits.</p> |
| <p>Panics if <code>permits</code> exceeds <a href="struct.Semaphore.html#associatedconstant.MAX_PERMITS" title="Semaphore::MAX_PERMITS"><code>Semaphore::MAX_PERMITS</code></a>.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.available_permits" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#192-194">source</a><h4 class="code-header">pub fn <a href="#method.available_permits" class="fnname">available_permits</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a></h4></section></summary><div class="docblock"><p>Returns the current number of available permits.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.add_permits" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#199-201">source</a><h4 class="code-header">pub fn <a href="#method.add_permits" class="fnname">add_permits</a>(&self, n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>)</h4></section></summary><div class="docblock"><p>Adds <code>n</code> new permits to the semaphore.</p> |
| <p>The maximum number of permits is <a href="struct.Semaphore.html#associatedconstant.MAX_PERMITS" title="Semaphore::MAX_PERMITS"><code>Semaphore::MAX_PERMITS</code></a>, and this function will panic if the limit is exceeded.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.acquire" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#237-254">source</a><h4 class="code-header">pub async fn <a href="#method.acquire" class="fnname">acquire</a>(&self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.SemaphorePermit.html" title="struct tokio::sync::SemaphorePermit">SemaphorePermit</a><'_>, <a class="struct" href="struct.AcquireError.html" title="struct tokio::sync::AcquireError">AcquireError</a>></h4></section></summary><div class="docblock"><p>Acquires a permit from the semaphore.</p> |
| <p>If the semaphore has been closed, this returns an <a href="struct.AcquireError.html"><code>AcquireError</code></a>. |
| Otherwise, this returns a <a href="struct.SemaphorePermit.html"><code>SemaphorePermit</code></a> representing the |
| acquired permit.</p> |
| <h5 id="cancel-safety"><a href="#cancel-safety">Cancel safety</a></h5> |
| <p>This method uses a queue to fairly distribute permits in the order they |
| were requested. Cancelling a call to <code>acquire</code> makes you lose your place |
| in the queue.</p> |
| <h5 id="examples-1"><a href="#examples-1">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::Semaphore; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Semaphore::new(<span class="number">2</span>); |
| |
| <span class="kw">let </span>permit_1 = semaphore.acquire().<span class="kw">await</span>.unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">1</span>); |
| |
| <span class="kw">let </span>permit_2 = semaphore.acquire().<span class="kw">await</span>.unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">0</span>); |
| |
| drop(permit_1); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">1</span>); |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.acquire_many" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#284-302">source</a><h4 class="code-header">pub async fn <a href="#method.acquire_many" class="fnname">acquire_many</a>(<br> &self,<br> n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a><br>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.SemaphorePermit.html" title="struct tokio::sync::SemaphorePermit">SemaphorePermit</a><'_>, <a class="struct" href="struct.AcquireError.html" title="struct tokio::sync::AcquireError">AcquireError</a>></h4></section></summary><div class="docblock"><p>Acquires <code>n</code> permits from the semaphore.</p> |
| <p>If the semaphore has been closed, this returns an <a href="struct.AcquireError.html"><code>AcquireError</code></a>. |
| Otherwise, this returns a <a href="struct.SemaphorePermit.html"><code>SemaphorePermit</code></a> representing the |
| acquired permits.</p> |
| <h5 id="cancel-safety-1"><a href="#cancel-safety-1">Cancel safety</a></h5> |
| <p>This method uses a queue to fairly distribute permits in the order they |
| were requested. Cancelling a call to <code>acquire_many</code> makes you lose your |
| place in the queue.</p> |
| <h5 id="examples-2"><a href="#examples-2">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::Semaphore; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Semaphore::new(<span class="number">5</span>); |
| |
| <span class="kw">let </span>permit = semaphore.acquire_many(<span class="number">3</span>).<span class="kw">await</span>.unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">2</span>); |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_acquire" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#332-340">source</a><h4 class="code-header">pub fn <a href="#method.try_acquire" class="fnname">try_acquire</a>(&self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.SemaphorePermit.html" title="struct tokio::sync::SemaphorePermit">SemaphorePermit</a><'_>, <a class="enum" href="enum.TryAcquireError.html" title="enum tokio::sync::TryAcquireError">TryAcquireError</a>></h4></section></summary><div class="docblock"><p>Tries to acquire a permit from the semaphore.</p> |
| <p>If the semaphore has been closed, this returns a <a href="enum.TryAcquireError.html#variant.Closed"><code>TryAcquireError::Closed</code></a> |
| and a <a href="enum.TryAcquireError.html#variant.NoPermits"><code>TryAcquireError::NoPermits</code></a> if there are no permits left. Otherwise, |
| this returns a <a href="struct.SemaphorePermit.html"><code>SemaphorePermit</code></a> representing the acquired permits.</p> |
| <h5 id="examples-3"><a href="#examples-3">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::{Semaphore, TryAcquireError}; |
| |
| <span class="kw">let </span>semaphore = Semaphore::new(<span class="number">2</span>); |
| |
| <span class="kw">let </span>permit_1 = semaphore.try_acquire().unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">1</span>); |
| |
| <span class="kw">let </span>permit_2 = semaphore.try_acquire().unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">0</span>); |
| |
| <span class="kw">let </span>permit_3 = semaphore.try_acquire(); |
| <span class="macro">assert_eq!</span>(permit_3.err(), <span class="prelude-val">Some</span>(TryAcquireError::NoPermits));</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_acquire_many" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#367-375">source</a><h4 class="code-header">pub fn <a href="#method.try_acquire_many" class="fnname">try_acquire_many</a>(<br> &self,<br> n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a><br>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.SemaphorePermit.html" title="struct tokio::sync::SemaphorePermit">SemaphorePermit</a><'_>, <a class="enum" href="enum.TryAcquireError.html" title="enum tokio::sync::TryAcquireError">TryAcquireError</a>></h4></section></summary><div class="docblock"><p>Tries to acquire <code>n</code> permits from the semaphore.</p> |
| <p>If the semaphore has been closed, this returns a <a href="enum.TryAcquireError.html#variant.Closed"><code>TryAcquireError::Closed</code></a> |
| and a <a href="enum.TryAcquireError.html#variant.NoPermits"><code>TryAcquireError::NoPermits</code></a> if there are not enough permits left. |
| Otherwise, this returns a <a href="struct.SemaphorePermit.html"><code>SemaphorePermit</code></a> representing the acquired permits.</p> |
| <h5 id="examples-4"><a href="#examples-4">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::{Semaphore, TryAcquireError}; |
| |
| <span class="kw">let </span>semaphore = Semaphore::new(<span class="number">4</span>); |
| |
| <span class="kw">let </span>permit_1 = semaphore.try_acquire_many(<span class="number">3</span>).unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">1</span>); |
| |
| <span class="kw">let </span>permit_2 = semaphore.try_acquire_many(<span class="number">2</span>); |
| <span class="macro">assert_eq!</span>(permit_2.err(), <span class="prelude-val">Some</span>(TryAcquireError::NoPermits));</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.acquire_owned" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#419-436">source</a><h4 class="code-header">pub async fn <a href="#method.acquire_owned" class="fnname">acquire_owned</a>(<br> self: <a class="struct" href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html" title="struct alloc::sync::Arc">Arc</a><Self><br>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.OwnedSemaphorePermit.html" title="struct tokio::sync::OwnedSemaphorePermit">OwnedSemaphorePermit</a>, <a class="struct" href="struct.AcquireError.html" title="struct tokio::sync::AcquireError">AcquireError</a>></h4></section></summary><div class="docblock"><p>Acquires a permit from the semaphore.</p> |
| <p>The semaphore must be wrapped in an <a href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html"><code>Arc</code></a> to call this method. |
| If the semaphore has been closed, this returns an <a href="struct.AcquireError.html"><code>AcquireError</code></a>. |
| Otherwise, this returns a <a href="struct.OwnedSemaphorePermit.html"><code>OwnedSemaphorePermit</code></a> representing the |
| acquired permit.</p> |
| <h5 id="cancel-safety-2"><a href="#cancel-safety-2">Cancel safety</a></h5> |
| <p>This method uses a queue to fairly distribute permits in the order they |
| were requested. Cancelling a call to <code>acquire_owned</code> makes you lose your |
| place in the queue.</p> |
| <h5 id="examples-5"><a href="#examples-5">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>tokio::sync::Semaphore; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Arc::new(Semaphore::new(<span class="number">3</span>)); |
| <span class="kw">let </span><span class="kw-2">mut </span>join_handles = Vec::new(); |
| |
| <span class="kw">for _ in </span><span class="number">0</span>..<span class="number">5 </span>{ |
| <span class="kw">let </span>permit = semaphore.clone().acquire_owned().<span class="kw">await</span>.unwrap(); |
| join_handles.push(tokio::spawn(<span class="kw">async move </span>{ |
| <span class="comment">// perform task... |
| // explicitly own `permit` in the task |
| </span>drop(permit); |
| })); |
| } |
| |
| <span class="kw">for </span>handle <span class="kw">in </span>join_handles { |
| handle.<span class="kw">await</span>.unwrap(); |
| } |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.acquire_many_owned" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#480-500">source</a><h4 class="code-header">pub async fn <a href="#method.acquire_many_owned" class="fnname">acquire_many_owned</a>(<br> self: <a class="struct" href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html" title="struct alloc::sync::Arc">Arc</a><Self>,<br> n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a><br>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.OwnedSemaphorePermit.html" title="struct tokio::sync::OwnedSemaphorePermit">OwnedSemaphorePermit</a>, <a class="struct" href="struct.AcquireError.html" title="struct tokio::sync::AcquireError">AcquireError</a>></h4></section></summary><div class="docblock"><p>Acquires <code>n</code> permits from the semaphore.</p> |
| <p>The semaphore must be wrapped in an <a href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html"><code>Arc</code></a> to call this method. |
| If the semaphore has been closed, this returns an <a href="struct.AcquireError.html"><code>AcquireError</code></a>. |
| Otherwise, this returns a <a href="struct.OwnedSemaphorePermit.html"><code>OwnedSemaphorePermit</code></a> representing the |
| acquired permit.</p> |
| <h5 id="cancel-safety-3"><a href="#cancel-safety-3">Cancel safety</a></h5> |
| <p>This method uses a queue to fairly distribute permits in the order they |
| were requested. Cancelling a call to <code>acquire_many_owned</code> makes you lose |
| your place in the queue.</p> |
| <h5 id="examples-6"><a href="#examples-6">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>tokio::sync::Semaphore; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Arc::new(Semaphore::new(<span class="number">10</span>)); |
| <span class="kw">let </span><span class="kw-2">mut </span>join_handles = Vec::new(); |
| |
| <span class="kw">for _ in </span><span class="number">0</span>..<span class="number">5 </span>{ |
| <span class="kw">let </span>permit = semaphore.clone().acquire_many_owned(<span class="number">2</span>).<span class="kw">await</span>.unwrap(); |
| join_handles.push(tokio::spawn(<span class="kw">async move </span>{ |
| <span class="comment">// perform task... |
| // explicitly own `permit` in the task |
| </span>drop(permit); |
| })); |
| } |
| |
| <span class="kw">for </span>handle <span class="kw">in </span>join_handles { |
| handle.<span class="kw">await</span>.unwrap(); |
| } |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_acquire_owned" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#534-542">source</a><h4 class="code-header">pub fn <a href="#method.try_acquire_owned" class="fnname">try_acquire_owned</a>(<br> self: <a class="struct" href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html" title="struct alloc::sync::Arc">Arc</a><Self><br>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.OwnedSemaphorePermit.html" title="struct tokio::sync::OwnedSemaphorePermit">OwnedSemaphorePermit</a>, <a class="enum" href="enum.TryAcquireError.html" title="enum tokio::sync::TryAcquireError">TryAcquireError</a>></h4></section></summary><div class="docblock"><p>Tries to acquire a permit from the semaphore.</p> |
| <p>The semaphore must be wrapped in an <a href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html"><code>Arc</code></a> to call this method. If |
| the semaphore has been closed, this returns a <a href="enum.TryAcquireError.html#variant.Closed"><code>TryAcquireError::Closed</code></a> |
| and a <a href="enum.TryAcquireError.html#variant.NoPermits"><code>TryAcquireError::NoPermits</code></a> if there are no permits left. |
| Otherwise, this returns a <a href="struct.OwnedSemaphorePermit.html"><code>OwnedSemaphorePermit</code></a> representing the |
| acquired permit.</p> |
| <h5 id="examples-7"><a href="#examples-7">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>tokio::sync::{Semaphore, TryAcquireError}; |
| |
| <span class="kw">let </span>semaphore = Arc::new(Semaphore::new(<span class="number">2</span>)); |
| |
| <span class="kw">let </span>permit_1 = Arc::clone(<span class="kw-2">&</span>semaphore).try_acquire_owned().unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">1</span>); |
| |
| <span class="kw">let </span>permit_2 = Arc::clone(<span class="kw-2">&</span>semaphore).try_acquire_owned().unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">0</span>); |
| |
| <span class="kw">let </span>permit_3 = semaphore.try_acquire_owned(); |
| <span class="macro">assert_eq!</span>(permit_3.err(), <span class="prelude-val">Some</span>(TryAcquireError::NoPermits));</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_acquire_many_owned" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#573-584">source</a><h4 class="code-header">pub fn <a href="#method.try_acquire_many_owned" class="fnname">try_acquire_many_owned</a>(<br> self: <a class="struct" href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html" title="struct alloc::sync::Arc">Arc</a><Self>,<br> n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a><br>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="struct.OwnedSemaphorePermit.html" title="struct tokio::sync::OwnedSemaphorePermit">OwnedSemaphorePermit</a>, <a class="enum" href="enum.TryAcquireError.html" title="enum tokio::sync::TryAcquireError">TryAcquireError</a>></h4></section></summary><div class="docblock"><p>Tries to acquire <code>n</code> permits from the semaphore.</p> |
| <p>The semaphore must be wrapped in an <a href="https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html"><code>Arc</code></a> to call this method. If |
| the semaphore has been closed, this returns a <a href="enum.TryAcquireError.html#variant.Closed"><code>TryAcquireError::Closed</code></a> |
| and a <a href="enum.TryAcquireError.html#variant.NoPermits"><code>TryAcquireError::NoPermits</code></a> if there are no permits left. |
| Otherwise, this returns a <a href="struct.OwnedSemaphorePermit.html"><code>OwnedSemaphorePermit</code></a> representing the |
| acquired permit.</p> |
| <h5 id="examples-8"><a href="#examples-8">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>tokio::sync::{Semaphore, TryAcquireError}; |
| |
| <span class="kw">let </span>semaphore = Arc::new(Semaphore::new(<span class="number">4</span>)); |
| |
| <span class="kw">let </span>permit_1 = Arc::clone(<span class="kw-2">&</span>semaphore).try_acquire_many_owned(<span class="number">3</span>).unwrap(); |
| <span class="macro">assert_eq!</span>(semaphore.available_permits(), <span class="number">1</span>); |
| |
| <span class="kw">let </span>permit_2 = semaphore.try_acquire_many_owned(<span class="number">2</span>); |
| <span class="macro">assert_eq!</span>(permit_2.err(), <span class="prelude-val">Some</span>(TryAcquireError::NoPermits));</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.close" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#615-617">source</a><h4 class="code-header">pub fn <a href="#method.close" class="fnname">close</a>(&self)</h4></section></summary><div class="docblock"><p>Closes the semaphore.</p> |
| <p>This prevents the semaphore from issuing new permits and notifies all pending waiters.</p> |
| <h5 id="examples-9"><a href="#examples-9">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::Semaphore; |
| <span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>tokio::sync::TryAcquireError; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>semaphore = Arc::new(Semaphore::new(<span class="number">1</span>)); |
| <span class="kw">let </span>semaphore2 = semaphore.clone(); |
| |
| tokio::spawn(<span class="kw">async move </span>{ |
| <span class="kw">let </span>permit = semaphore.acquire_many(<span class="number">2</span>).<span class="kw">await</span>; |
| <span class="macro">assert!</span>(permit.is_err()); |
| <span class="macro">println!</span>(<span class="string">"waiter received error"</span>); |
| }); |
| |
| <span class="macro">println!</span>(<span class="string">"closing semaphore"</span>); |
| semaphore2.close(); |
| |
| <span class="comment">// Cannot obtain more permits |
| </span><span class="macro">assert_eq!</span>(semaphore2.try_acquire().err(), <span class="prelude-val">Some</span>(TryAcquireError::Closed)) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.is_closed" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#620-622">source</a><h4 class="code-header">pub fn <a href="#method.is_closed" class="fnname">is_closed</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><div class="docblock"><p>Returns true if the semaphore is closed</p> |
| </div></details></div></details></div><h2 id="trait-implementations" class="small-section-header">Trait Implementations<a href="#trait-implementations" class="anchor"></a></h2><div id="trait-implementations-list"><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Debug-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#78">source</a><a href="#impl-Debug-for-Semaphore" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.fmt" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../src/tokio/sync/semaphore.rs.html#78">source</a><a href="#method.fmt" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt" class="fnname">fmt</a>(&self, f: &mut <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a><'_>) -> <a class="type" href="https://doc.rust-lang.org/nightly/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/nightly/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></div></details></div></details></div><h2 id="synthetic-implementations" class="small-section-header">Auto Trait Implementations<a href="#synthetic-implementations" class="anchor"></a></h2><div id="synthetic-implementations-list"><section id="impl-RefUnwindSafe-for-Semaphore" class="impl has-srclink"><a href="#impl-RefUnwindSafe-for-Semaphore" class="anchor"></a><h3 class="code-header">impl !<a class="trait" href="https://doc.rust-lang.org/nightly/core/panic/unwind_safe/trait.RefUnwindSafe.html" title="trait core::panic::unwind_safe::RefUnwindSafe">RefUnwindSafe</a> for <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section><section id="impl-Send-for-Semaphore" class="impl has-srclink"><a href="#impl-Send-for-Semaphore" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section><section id="impl-Sync-for-Semaphore" class="impl has-srclink"><a href="#impl-Sync-for-Semaphore" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section><section id="impl-Unpin-for-Semaphore" class="impl has-srclink"><a href="#impl-Unpin-for-Semaphore" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a> for <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section><section id="impl-UnwindSafe-for-Semaphore" class="impl has-srclink"><a href="#impl-UnwindSafe-for-Semaphore" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a> for <a class="struct" href="struct.Semaphore.html" title="struct tokio::sync::Semaphore">Semaphore</a></h3></section></div><h2 id="blanket-implementations" class="small-section-header">Blanket Implementations<a href="#blanket-implementations" class="anchor"></a></h2><div id="blanket-implementations-list"><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Any-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/any.rs.html#200">source</a><a href="#impl-Any-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/any/trait.Any.html" title="trait core::any::Any">Any</a> for T<span class="where fmt-newline">where<br> T: 'static + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.type_id" class="method trait-impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/any.rs.html#201">source</a><a href="#method.type_id" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/any/trait.Any.html#tymethod.type_id" class="fnname">type_id</a>(&self) -> <a class="struct" href="https://doc.rust-lang.org/nightly/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/nightly/core/any/trait.Any.html#tymethod.type_id">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Borrow%3CT%3E-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#211">source</a><a href="#impl-Borrow%3CT%3E-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a><T> for T<span class="where fmt-newline">where<br> T: ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.borrow" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#213">source</a></span><a href="#method.borrow" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html#tymethod.borrow" class="fnname">borrow</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>T</h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html#tymethod.borrow">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-BorrowMut%3CT%3E-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#220">source</a><a href="#impl-BorrowMut%3CT%3E-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.BorrowMut.html" title="trait core::borrow::BorrowMut">BorrowMut</a><T> for T<span class="where fmt-newline">where<br> T: ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.borrow_mut" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#221">source</a></span><a href="#method.borrow_mut" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut" class="fnname">borrow_mut</a>(&mut self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>T</h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-From%3CT%3E-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#733">source</a><a href="#impl-From%3CT%3E-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html" title="trait core::convert::From">From</a><T> for T</h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.from" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#736">source</a></span><a href="#method.from" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html#tymethod.from" class="fnname">from</a>(t: T) -> T</h4></section></summary><div class="docblock"><p>Returns the argument unchanged.</p> |
| </div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Into%3CU%3E-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#717">source</a><a href="#impl-Into%3CU%3E-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a><U> for T<span class="where fmt-newline">where<br> U: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html" title="trait core::convert::From">From</a><T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.into" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#725">source</a></span><a href="#method.into" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html#tymethod.into" class="fnname">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/nightly/core/convert/trait.From.html" title="From">From</a><T> for U</code> chooses to do.</p> |
| </div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-TryFrom%3CU%3E-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#775">source</a><a href="#impl-TryFrom%3CU%3E-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><U> for T<span class="where fmt-newline">where<br> U: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a><T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Error-1" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-1" class="anchor"></a><h4 class="code-header">type <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="https://doc.rust-lang.org/nightly/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="rustdoc-toggle method-toggle" open><summary><section id="method.try_from" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#781">source</a></span><a href="#method.try_from" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#tymethod.try_from" class="fnname">try_from</a>(value: U) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, <T as <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><U>>::<a class="associatedtype" href="https://doc.rust-lang.org/nightly/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="rustdoc-toggle implementors-toggle"><summary><section id="impl-TryInto%3CU%3E-for-Semaphore" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#760">source</a><a href="#impl-TryInto%3CU%3E-for-Semaphore" class="anchor"></a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html" title="trait core::convert::TryInto">TryInto</a><U> for T<span class="where fmt-newline">where<br> U: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Error" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error" class="anchor"></a><h4 class="code-header">type <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html#associatedtype.Error" class="associatedtype">Error</a> = <U as <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>>::<a class="associatedtype" href="https://doc.rust-lang.org/nightly/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="rustdoc-toggle method-toggle" open><summary><section id="method.try_into" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#766">source</a></span><a href="#method.try_into" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html#tymethod.try_into" class="fnname">try_into</a>(self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><U, <U as <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>>::<a class="associatedtype" href="https://doc.rust-lang.org/nightly/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><div id="rustdoc-vars" data-root-path="../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
