| <!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="Permits to send one value into the channel."><meta name="keywords" content="rust, rustlang, rust-lang, Permit"><title>Permit in tokio::sync::mpsc - 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 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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="#">Permit</a></h2><div class="sidebar-elems"><section><h3><a href="#implementations">Methods</a></h3><ul class="block"><li><a href="#method.send">send</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block"><li><a href="#impl-Debug-for-Permit%3C%27_%2C%20T%3E">Debug</a></li><li><a href="#impl-Drop-for-Permit%3C%27_%2C%20T%3E">Drop</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block"><li><a href="#impl-RefUnwindSafe-for-Permit%3C%27a%2C%20T%3E">!RefUnwindSafe</a></li><li><a href="#impl-Send-for-Permit%3C%27a%2C%20T%3E">Send</a></li><li><a href="#impl-Sync-for-Permit%3C%27a%2C%20T%3E">Sync</a></li><li><a href="#impl-Unpin-for-Permit%3C%27a%2C%20T%3E">Unpin</a></li><li><a href="#impl-UnwindSafe-for-Permit%3C%27a%2C%20T%3E">!UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block"><li><a href="#impl-Any-for-Permit%3C%27a%2C%20T%3E">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-Permit%3C%27a%2C%20T%3E">Borrow<T></a></li><li><a href="#impl-BorrowMut%3CT%3E-for-Permit%3C%27a%2C%20T%3E">BorrowMut<T></a></li><li><a href="#impl-From%3CT%3E-for-Permit%3C%27a%2C%20T%3E">From<T></a></li><li><a href="#impl-Into%3CU%3E-for-Permit%3C%27a%2C%20T%3E">Into<U></a></li><li><a href="#impl-TryFrom%3CU%3E-for-Permit%3C%27a%2C%20T%3E">TryFrom<U></a></li><li><a href="#impl-TryInto%3CU%3E-for-Permit%3C%27a%2C%20T%3E">TryInto<U></a></li></ul></section><h2><a href="index.html">In tokio::sync::mpsc</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 href="index.html">mpsc</a>::<wbr><a class="struct" href="#">Permit</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/mpsc/bounded.rs.html#67-69">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 Permit<'a, T> { /* private fields */ }</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Permits to send one value into the channel.</p> |
| <p><code>Permit</code> values are returned by <a href="struct.Sender.html#method.reserve"><code>Sender::reserve()</code></a> and <a href="struct.Sender.html#method.try_reserve"><code>Sender::try_reserve()</code></a> |
| and are used to guarantee channel capacity before generating a message to send.</p> |
| </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-Permit%3C%27_%2C%20T%3E" class="impl has-srclink"><a class="srclink rightside" href="../../../src/tokio/sync/mpsc/bounded.rs.html#1129-1170">source</a><a href="#impl-Permit%3C%27_%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'_, T></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.send" class="method has-srclink"><a class="srclink rightside" href="../../../src/tokio/sync/mpsc/bounded.rs.html#1162-1169">source</a><h4 class="code-header">pub fn <a href="#method.send" class="fnname">send</a>(self, value: T)</h4></section></summary><div class="docblock"><p>Sends a value using the reserved capacity.</p> |
| <p>Capacity for the message has already been reserved. The message is sent |
| to the receiver and the permit is consumed. The operation will succeed |
| even if the receiver half has been closed. See <a href="struct.Receiver.html#method.close"><code>Receiver::close</code></a> for |
| more details on performing a clean shutdown.</p> |
| <h5 id="examples"><a href="#examples">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::sync::mpsc; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() { |
| <span class="kw">let </span>(tx, <span class="kw-2">mut </span>rx) = mpsc::channel(<span class="number">1</span>); |
| |
| <span class="comment">// Reserve capacity |
| </span><span class="kw">let </span>permit = tx.reserve().<span class="kw">await</span>.unwrap(); |
| |
| <span class="comment">// Trying to send directly on the `tx` will fail due to no |
| // available capacity. |
| </span><span class="macro">assert!</span>(tx.try_send(<span class="number">123</span>).is_err()); |
| |
| <span class="comment">// Send a message on the permit |
| </span>permit.send(<span class="number">456</span>); |
| |
| <span class="comment">// The value sent on the permit is received |
| </span><span class="macro">assert_eq!</span>(rx.recv().<span class="kw">await</span>.unwrap(), <span class="number">456</span>); |
| }</code></pre></div> |
| </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-Permit%3C%27_%2C%20T%3E" class="impl has-srclink"><a class="srclink rightside" href="../../../src/tokio/sync/mpsc/bounded.rs.html#1189-1195">source</a><a href="#impl-Debug-for-Permit%3C%27_%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> Debug for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'_, T></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/mpsc/bounded.rs.html#1190-1194">source</a><a href="#method.fmt" class="anchor"></a><h4 class="code-header">fn <a class="fnname">fmt</a>(&self, fmt: &mut Formatter<'_>) -> Result</h4></section></summary><div class='docblock'>Formats the value using the given formatter. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Drop-for-Permit%3C%27_%2C%20T%3E" class="impl has-srclink"><a class="srclink rightside" href="../../../src/tokio/sync/mpsc/bounded.rs.html#1172-1187">source</a><a href="#impl-Drop-for-Permit%3C%27_%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> Drop for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'_, T></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.drop" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../../src/tokio/sync/mpsc/bounded.rs.html#1173-1186">source</a><a href="#method.drop" class="anchor"></a><h4 class="code-header">fn <a class="fnname">drop</a>(&mut self)</h4></section></summary><div class='docblock'>Executes the destructor for this type. <a>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-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-RefUnwindSafe-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<'a, T> !RefUnwindSafe for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'a, T></h3></section><section id="impl-Send-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-Send-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<'a, T> Send for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'a, T><span class="where fmt-newline">where<br> T: Send,</span></h3></section><section id="impl-Sync-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-Sync-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<'a, T> Sync for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'a, T><span class="where fmt-newline">where<br> T: Send,</span></h3></section><section id="impl-Unpin-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-Unpin-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<'a, T> Unpin for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'a, T></h3></section><section id="impl-UnwindSafe-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-UnwindSafe-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<'a, T> !UnwindSafe for <a class="struct" href="struct.Permit.html" title="struct tokio::sync::mpsc::Permit">Permit</a><'a, T></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-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-Any-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> Any for T<span class="where fmt-newline">where<br> T: 'static + ?Sized,</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 href="#method.type_id" class="anchor"></a><h4 class="code-header">fn <a class="fnname">type_id</a>(&self) -> TypeId</h4></section></summary><div class='docblock'>Gets the <code>TypeId</code> of <code>self</code>. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Borrow%3CT%3E-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-Borrow%3CT%3E-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> Borrow<T> for T<span class="where fmt-newline">where<br> T: ?Sized,</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="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span><a href="#method.borrow" class="anchor"></a><h4 class="code-header">fn <a class="fnname">borrow</a>(&self) -> &T</h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-BorrowMut%3CT%3E-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-BorrowMut%3CT%3E-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> BorrowMut<T> for T<span class="where fmt-newline">where<br> T: ?Sized,</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="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span><a href="#method.borrow_mut" class="anchor"></a><h4 class="code-header">fn <a class="fnname">borrow_mut</a>(&mut self) -> &mut T</h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a>Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-From%3CT%3E-for-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-From%3CT%3E-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T> From<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="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.from" class="anchor"></a><h4 class="code-header">fn <a 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-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-Into%3CU%3E-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T, U> Into<U> for T<span class="where fmt-newline">where<br> U: From<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="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.into" class="anchor"></a><h4 class="code-header">fn <a 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>[From]<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-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-TryFrom%3CU%3E-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T, U> TryFrom<U> for T<span class="where fmt-newline">where<br> U: Into<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 class="associatedtype">Error</a> = Infallible</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="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.try_from" class="anchor"></a><h4 class="code-header">fn <a class="fnname">try_from</a>(value: U) -> Result<T, <T as TryFrom<U>>::Error></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-Permit%3C%27a%2C%20T%3E" class="impl has-srclink"><a href="#impl-TryInto%3CU%3E-for-Permit%3C%27a%2C%20T%3E" class="anchor"></a><h3 class="code-header">impl<T, U> TryInto<U> for T<span class="where fmt-newline">where<br> U: TryFrom<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 class="associatedtype">Error</a> = <U as TryFrom<T>>::Error</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="since rightside" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span><a href="#method.try_into" class="anchor"></a><h4 class="code-header">fn <a class="fnname">try_into</a>(self) -> Result<U, <U as TryFrom<T>>::Error></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> |
