<!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="API documentation for the Rust `mpsc` mod in crate `std`."><meta name="keywords" content="rust, rustlang, rust-lang, mpsc"><title>std::sync::mpsc - Rust</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc mod"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a><p class='location'>Module mpsc</p><div class="sidebar-elems"><div class="block items"><ul><li><a href="#structs">Structs</a></li><li><a href="#enums">Enums</a></li><li><a href="#functions">Functions</a></li></ul></div><p class='location'><a href='../../index.html'>std</a>::<wbr><a href='../index.html'>sync</a></p><script>window.sidebarCurrent = {name: 'mpsc', ty: 'mod', relpath: '../'};</script><script defer src="../sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='in-band'>Module <a href='../../index.html'>std</a>::<wbr><a href='../index.html'>sync</a>::<wbr><a class="mod" href=''>mpsc</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../../../src/std/sync/mpsc/mod.rs.html#11-3102' title='goto source code'>[src]</a></span></h1><div class='docblock'><p>Multi-producer, single-consumer FIFO queue communication primitives.</p>
<p>This module provides message-based communication over channels, concretely
defined among three types:</p>
<ul>
<li><a href="../../../std/sync/mpsc/struct.Sender.html"><code>Sender</code></a></li>
<li><a href="../../../std/sync/mpsc/struct.SyncSender.html"><code>SyncSender</code></a></li>
<li><a href="../../../std/sync/mpsc/struct.Receiver.html"><code>Receiver</code></a></li>
</ul>
<p>A <a href="../../../std/sync/mpsc/struct.Sender.html"><code>Sender</code></a> or <a href="../../../std/sync/mpsc/struct.SyncSender.html"><code>SyncSender</code></a> is used to send data to a <a href="../../../std/sync/mpsc/struct.Receiver.html"><code>Receiver</code></a>. Both
senders are clone-able (multi-producer) such that many threads can send
simultaneously to one receiver (single-consumer).</p>
<p>These channels come in two flavors:</p>
<ol>
<li>
<p>An asynchronous, infinitely buffered channel. The <a href="../../../std/sync/mpsc/fn.channel.html"><code>channel</code></a> function
will return a <code>(Sender, Receiver)</code> tuple where all sends will be
<strong>asynchronous</strong> (they never block). The channel conceptually has an
infinite buffer.</p>
</li>
<li>
<p>A synchronous, bounded channel. The <a href="../../../std/sync/mpsc/fn.sync_channel.html"><code>sync_channel</code></a> function will
return a <code>(SyncSender, Receiver)</code> tuple where the storage for pending
messages is a pre-allocated buffer of a fixed size. All sends will be
<strong>synchronous</strong> by blocking until there is buffer space available. Note
that a bound of 0 is allowed, causing the channel to become a "rendezvous"
channel where each sender atomically hands off a message to a receiver.</p>
</li>
</ol>
<h2 id="disconnection" class="section-header"><a href="#disconnection">Disconnection</a></h2>
<p>The send and receive operations on channels will all return a <a href="../../../std/result/enum.Result.html"><code>Result</code></a>
indicating whether the operation succeeded or not. An unsuccessful operation
is normally indicative of the other half of a channel having "hung up" by
being dropped in its corresponding thread.</p>
<p>Once half of a channel has been deallocated, most operations can no longer
continue to make progress, so <a href="../../../std/result/enum.Result.html#variant.Err"><code>Err</code></a> will be returned. Many applications
will continue to <a href="../../../std/result/enum.Result.html#method.unwrap"><code>unwrap</code></a> the results returned from this module,
instigating a propagation of failure among threads if one unexpectedly dies.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<p>Simple usage:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">thread</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::<span class="ident">mpsc</span>::<span class="ident">channel</span>;
<span class="comment">// Create a simple streaming channel</span>
<span class="kw">let</span> (<span class="ident">tx</span>, <span class="ident">rx</span>) <span class="op">=</span> <span class="ident">channel</span>();
<span class="ident">thread</span>::<span class="ident">spawn</span>(<span class="kw">move</span><span class="op">||</span> {
<span class="ident">tx</span>.<span class="ident">send</span>(<span class="number">10</span>).<span class="ident">unwrap</span>();
});
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">rx</span>.<span class="ident">recv</span>().<span class="ident">unwrap</span>(), <span class="number">10</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Athread%3B%0Ause%20std%3A%3Async%3A%3Ampsc%3A%3Achannel%3B%0A%0A%2F%2F%20Create%20a%20simple%20streaming%20channel%0Alet%20(tx%2C%20rx)%20%3D%20channel()%3B%0Athread%3A%3Aspawn(move%7C%7C%20%7B%0A%20%20%20%20tx.send(10).unwrap()%3B%0A%7D)%3B%0Aassert_eq!(rx.recv().unwrap()%2C%2010)%3B%0A%7D">Run</a></pre>
<p>Shared usage:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">thread</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::<span class="ident">mpsc</span>::<span class="ident">channel</span>;
<span class="comment">// Create a shared channel that can be sent along from many threads</span>
<span class="comment">// where tx is the sending half (tx for transmission), and rx is the receiving</span>
<span class="comment">// half (rx for receiving).</span>
<span class="kw">let</span> (<span class="ident">tx</span>, <span class="ident">rx</span>) <span class="op">=</span> <span class="ident">channel</span>();
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">10</span> {
<span class="kw">let</span> <span class="ident">tx</span> <span class="op">=</span> <span class="ident">tx</span>.<span class="ident">clone</span>();
<span class="ident">thread</span>::<span class="ident">spawn</span>(<span class="kw">move</span><span class="op">||</span> {
<span class="ident">tx</span>.<span class="ident">send</span>(<span class="ident">i</span>).<span class="ident">unwrap</span>();
});
}
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">10</span> {
<span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="ident">rx</span>.<span class="ident">recv</span>().<span class="ident">unwrap</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="number">0</span> <span class="op"><=</span> <span class="ident">j</span> <span class="op">&&</span> <span class="ident">j</span> <span class="op"><</span> <span class="number">10</span>);
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Athread%3B%0Ause%20std%3A%3Async%3A%3Ampsc%3A%3Achannel%3B%0A%0A%2F%2F%20Create%20a%20shared%20channel%20that%20can%20be%20sent%20along%20from%20many%20threads%0A%2F%2F%20where%20tx%20is%20the%20sending%20half%20(tx%20for%20transmission)%2C%20and%20rx%20is%20the%20receiving%0A%2F%2F%20half%20(rx%20for%20receiving).%0Alet%20(tx%2C%20rx)%20%3D%20channel()%3B%0Afor%20i%20in%200..10%20%7B%0A%20%20%20%20let%20tx%20%3D%20tx.clone()%3B%0A%20%20%20%20thread%3A%3Aspawn(move%7C%7C%20%7B%0A%20%20%20%20%20%20%20%20tx.send(i).unwrap()%3B%0A%20%20%20%20%7D)%3B%0A%7D%0A%0Afor%20_%20in%200..10%20%7B%0A%20%20%20%20let%20j%20%3D%20rx.recv().unwrap()%3B%0A%20%20%20%20assert!(0%20%3C%3D%20j%20%26%26%20j%20%3C%2010)%3B%0A%7D%0A%7D">Run</a></pre>
<p>Propagating panics:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::<span class="ident">mpsc</span>::<span class="ident">channel</span>;
<span class="comment">// The call to recv() will return an error because the channel has already</span>
<span class="comment">// hung up (or been deallocated)</span>
<span class="kw">let</span> (<span class="ident">tx</span>, <span class="ident">rx</span>) <span class="op">=</span> <span class="ident">channel</span>::<span class="op"><</span><span class="ident">i32</span><span class="op">></span>();
<span class="ident">drop</span>(<span class="ident">tx</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">rx</span>.<span class="ident">recv</span>().<span class="ident">is_err</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Async%3A%3Ampsc%3A%3Achannel%3B%0A%0A%2F%2F%20The%20call%20to%20recv()%20will%20return%20an%20error%20because%20the%20channel%20has%20already%0A%2F%2F%20hung%20up%20(or%20been%20deallocated)%0Alet%20(tx%2C%20rx)%20%3D%20channel%3A%3A%3Ci32%3E()%3B%0Adrop(tx)%3B%0Aassert!(rx.recv().is_err())%3B%0A%7D">Run</a></pre>
<p>Synchronous channels:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">thread</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::<span class="ident">mpsc</span>::<span class="ident">sync_channel</span>;
<span class="kw">let</span> (<span class="ident">tx</span>, <span class="ident">rx</span>) <span class="op">=</span> <span class="ident">sync_channel</span>::<span class="op"><</span><span class="ident">i32</span><span class="op">></span>(<span class="number">0</span>);
<span class="ident">thread</span>::<span class="ident">spawn</span>(<span class="kw">move</span><span class="op">||</span> {
<span class="comment">// This will wait for the parent thread to start receiving</span>
<span class="ident">tx</span>.<span class="ident">send</span>(<span class="number">53</span>).<span class="ident">unwrap</span>();
});
<span class="ident">rx</span>.<span class="ident">recv</span>().<span class="ident">unwrap</span>();<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Athread%3B%0Ause%20std%3A%3Async%3A%3Ampsc%3A%3Async_channel%3B%0A%0Alet%20(tx%2C%20rx)%20%3D%20sync_channel%3A%3A%3Ci32%3E(0)%3B%0Athread%3A%3Aspawn(move%7C%7C%20%7B%0A%20%20%20%20%2F%2F%20This%20will%20wait%20for%20the%20parent%20thread%20to%20start%20receiving%0A%20%20%20%20tx.send(53).unwrap()%3B%0A%7D)%3B%0Arx.recv().unwrap()%3B%0A%7D">Run</a></pre>
</div><h2 id='structs' class='section-header'><a href="#structs">Structs</a></h2>
<table>
<tr class=' module-item'>
<td><a class="struct" href="struct.IntoIter.html"
title='struct std::sync::mpsc::IntoIter'>IntoIter</a></td>
<td class='docblock-short'>
<p>An owning iterator over messages on a <a href="struct.Receiver.html"><code>Receiver</code></a>,
created by <strong>Receiver::into_iter</strong>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.Iter.html"
title='struct std::sync::mpsc::Iter'>Iter</a></td>
<td class='docblock-short'>
<p>An iterator over messages on a <a href="struct.Receiver.html"><code>Receiver</code></a>, created by <a href="struct.Receiver.html#method.iter"><code>iter</code></a>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.Receiver.html"
title='struct std::sync::mpsc::Receiver'>Receiver</a></td>
<td class='docblock-short'>
<p>The receiving half of Rust's <a href="fn.channel.html"><code>channel</code></a> (or <a href="fn.sync_channel.html"><code>sync_channel</code></a>) type.
This half can only be owned by one thread.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.RecvError.html"
title='struct std::sync::mpsc::RecvError'>RecvError</a></td>
<td class='docblock-short'>
<p>An error returned from the <a href="struct.Receiver.html#method.recv"><code>recv</code></a> function on a <a href="struct.Receiver.html"><code>Receiver</code></a>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.SendError.html"
title='struct std::sync::mpsc::SendError'>SendError</a></td>
<td class='docblock-short'>
<p>An error returned from the <a href="struct.Sender.html#method.send"><code>Sender::send</code></a> or <a href="struct.SyncSender.html#method.send"><code>SyncSender::send</code></a>
function on <strong>channel</strong>s.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.Sender.html"
title='struct std::sync::mpsc::Sender'>Sender</a></td>
<td class='docblock-short'>
<p>The sending-half of Rust's asynchronous <a href="fn.channel.html"><code>channel</code></a> type. This half can only be
owned by one thread, but it can be cloned to send to other threads.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.SyncSender.html"
title='struct std::sync::mpsc::SyncSender'>SyncSender</a></td>
<td class='docblock-short'>
<p>The sending-half of Rust's synchronous <a href="fn.sync_channel.html"><code>sync_channel</code></a> type.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.TryIter.html"
title='struct std::sync::mpsc::TryIter'>TryIter</a></td>
<td class='docblock-short'>
<p>An iterator that attempts to yield all pending values for a <a href="struct.Receiver.html"><code>Receiver</code></a>,
created by <a href="struct.Receiver.html#method.try_iter"><code>try_iter</code></a>.</p>
</td>
</tr>
<tr class='unstable module-item'>
<td><a class="struct" href="struct.Handle.html"
title='struct std::sync::mpsc::Handle'>Handle</a></td>
<td class='docblock-short'>
[<div class='stab unstable'>Experimental</div>] <p>A handle to a receiver which is currently a member of a <code>Select</code> set of
receivers. This handle is used to keep the receiver in the set as well as
interact with the underlying receiver.</p>
</td>
</tr>
<tr class='unstable module-item'>
<td><a class="struct" href="struct.Select.html"
title='struct std::sync::mpsc::Select'>Select</a></td>
<td class='docblock-short'>
[<div class='stab unstable'>Experimental</div>] <p>The "receiver set" of the select interface. This structure is used to manage
a set of receivers which are being selected over.</p>
</td>
</tr></table><h2 id='enums' class='section-header'><a href="#enums">Enums</a></h2>
<table>
<tr class=' module-item'>
<td><a class="enum" href="enum.RecvTimeoutError.html"
title='enum std::sync::mpsc::RecvTimeoutError'>RecvTimeoutError</a></td>
<td class='docblock-short'>
<p>This enumeration is the list of possible errors that made <a href="struct.Receiver.html#method.recv_timeout"><code>recv_timeout</code></a>
unable to return data when called. This can occur with both a <a href="fn.channel.html"><code>channel</code></a> and
a <a href="fn.sync_channel.html"><code>sync_channel</code></a>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="enum" href="enum.TryRecvError.html"
title='enum std::sync::mpsc::TryRecvError'>TryRecvError</a></td>
<td class='docblock-short'>
<p>This enumeration is the list of the possible reasons that <a href="struct.Receiver.html#method.try_recv"><code>try_recv</code></a> could
not return data when called. This can occur with both a <a href="fn.channel.html"><code>channel</code></a> and
a <a href="fn.sync_channel.html"><code>sync_channel</code></a>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="enum" href="enum.TrySendError.html"
title='enum std::sync::mpsc::TrySendError'>TrySendError</a></td>
<td class='docblock-short'>
<p>This enumeration is the list of the possible error outcomes for the
<a href="struct.SyncSender.html#method.try_send"><code>try_send</code></a> method.</p>
</td>
</tr></table><h2 id='functions' class='section-header'><a href="#functions">Functions</a></h2>
<table>
<tr class=' module-item'>
<td><a class="fn" href="fn.channel.html"
title='fn std::sync::mpsc::channel'>channel</a></td>
<td class='docblock-short'>
<p>Creates a new asynchronous channel, returning the sender/receiver halves.
All data sent on the <a href="struct.Sender.html"><code>Sender</code></a> will become available on the <a href="struct.Receiver.html"><code>Receiver</code></a> in
the same order as it was sent, and no <a href="struct.Sender.html#method.send"><code>send</code></a> will block the calling thread
(this channel has an "infinite buffer", unlike <a href="fn.sync_channel.html"><code>sync_channel</code></a>, which will
block after its buffer limit is reached). <a href="struct.Receiver.html#method.recv"><code>recv</code></a> will block until a message
is available.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.sync_channel.html"
title='fn std::sync::mpsc::sync_channel'>sync_channel</a></td>
<td class='docblock-short'>
<p>Creates a new synchronous, bounded channel.
All data sent on the <a href="struct.SyncSender.html"><code>SyncSender</code></a> will become available on the <a href="struct.Receiver.html"><code>Receiver</code></a>
in the same order as it was sent. Like asynchronous <a href="fn.channel.html"><code>channel</code></a>s, the
<a href="struct.Receiver.html"><code>Receiver</code></a> will block until a message becomes available. <code>sync_channel</code>
differs greatly in the semantics of the sender, however.</p>
</td>
</tr></table></section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../";window.currentCrate = "std";</script><script src="../../../aliases.js"></script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>
distrib
>
Mageia
>
6
>
armv7hl
>
media
>
core-updates
>
by-pkgid
>
4e2dbb669434a7691662cb2f0ad38972
>
files
>
14833
