| <!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="Polls for readiness events on all registered values."><meta name="keywords" content="rust, rustlang, rust-lang, Poll"><title>Poll in mio - 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 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src="../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../mio/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">Poll</a></h2><div class="sidebar-elems"><section><h3><a href="#implementations">Methods</a></h3><ul class="block"><li><a href="#method.new">new</a></li><li><a href="#method.poll">poll</a></li><li><a href="#method.registry">registry</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block"><li><a href="#impl-AsRawFd-for-Poll">AsRawFd</a></li><li><a href="#impl-Debug-for-Poll">Debug</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block"><li><a href="#impl-RefUnwindSafe-for-Poll">RefUnwindSafe</a></li><li><a href="#impl-Send-for-Poll">Send</a></li><li><a href="#impl-Sync-for-Poll">Sync</a></li><li><a href="#impl-Unpin-for-Poll">Unpin</a></li><li><a href="#impl-UnwindSafe-for-Poll">UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block"><li><a href="#impl-Any-for-Poll">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-Poll">Borrow<T></a></li><li><a href="#impl-BorrowMut%3CT%3E-for-Poll">BorrowMut<T></a></li><li><a href="#impl-From%3CT%3E-for-Poll">From<T></a></li><li><a href="#impl-Into%3CU%3E-for-Poll">Into<U></a></li><li><a href="#impl-TryFrom%3CU%3E-for-Poll">TryFrom<U></a></li><li><a href="#impl-TryInto%3CU%3E-for-Poll">TryInto<U></a></li></ul></section><h2><a href="index.html">In mio</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">mio</a>::<wbr><a class="struct" href="#">Poll</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/mio/poll.rs.html#248-250">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 Poll { /* private fields */ }</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Polls for readiness events on all registered values.</p> |
| <p><code>Poll</code> allows a program to monitor a large number of <a href="./event/trait.Source.html"><code>event::Source</code></a>s, |
| waiting until one or more become “ready” for some class of operations; e.g. |
| reading and writing. An event source is considered ready if it is possible |
| to immediately perform a corresponding operation; e.g. <a href="./net/struct.TcpStream.html#method.read"><code>read</code></a> or |
| <a href="./net/struct.TcpStream.html#method.write"><code>write</code></a>.</p> |
| <p>To use <code>Poll</code>, an <code>event::Source</code> must first be registered with the <code>Poll</code> |
| instance using the <a href="struct.Registry.html#method.register"><code>register</code></a> method on its associated <code>Register</code>, |
| supplying readiness interest. The readiness interest tells <code>Poll</code> which |
| specific operations on the handle to monitor for readiness. A <code>Token</code> is |
| also passed to the <a href="struct.Registry.html#method.register"><code>register</code></a> function. When <code>Poll</code> returns a readiness |
| event, it will include this token. This associates the event with the |
| event source that generated the event.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <p>A basic example – establishing a <code>TcpStream</code> connection.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>mio::{Events, Poll, Interest, Token}; |
| <span class="kw">use </span>mio::net::TcpStream; |
| |
| <span class="kw">use </span>std::net::{<span class="self">self</span>, SocketAddr}; |
| |
| <span class="comment">// Bind a server socket to connect to. |
| </span><span class="kw">let </span>addr: SocketAddr = <span class="string">"127.0.0.1:0"</span>.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>server = net::TcpListener::bind(addr)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Construct a new `Poll` handle as well as the `Events` we'll store into |
| </span><span class="kw">let </span><span class="kw-2">mut </span>poll = Poll::new()<span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>events = Events::with_capacity(<span class="number">1024</span>); |
| |
| <span class="comment">// Connect the stream |
| </span><span class="kw">let </span><span class="kw-2">mut </span>stream = TcpStream::connect(server.local_addr()<span class="question-mark">?</span>)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Register the stream with `Poll` |
| </span>poll.registry().register(<span class="kw-2">&mut </span>stream, Token(<span class="number">0</span>), Interest::READABLE | Interest::WRITABLE)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Wait for the socket to become ready. This has to happens in a loop to |
| // handle spurious wakeups. |
| </span><span class="kw">loop </span>{ |
| poll.poll(<span class="kw-2">&mut </span>events, <span class="prelude-val">None</span>)<span class="question-mark">?</span>; |
| |
| <span class="kw">for </span>event <span class="kw">in </span><span class="kw-2">&</span>events { |
| <span class="kw">if </span>event.token() == Token(<span class="number">0</span>) && event.is_writable() { |
| <span class="comment">// The socket connected (probably, it could still be a spurious |
| // wakeup) |
| </span><span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| } |
| }</code></pre></div> |
| <h2 id="portability"><a href="#portability">Portability</a></h2> |
| <p>Using <code>Poll</code> provides a portable interface across supported platforms as |
| long as the caller takes the following into consideration:</p> |
| <h4 id="spurious-events"><a href="#spurious-events">Spurious events</a></h4> |
| <p><a href="struct.Poll.html#method.poll"><code>Poll::poll</code></a> may return readiness events even if the associated |
| event source is not actually ready. Given the same code, this may |
| happen more on some platforms than others. It is important to never assume |
| that, just because a readiness event was received, that the associated |
| operation will succeed as well.</p> |
| <p>If operation fails with <a href="https://doc.rust-lang.org/nightly/std/io/error/enum.ErrorKind.html#variant.WouldBlock"><code>WouldBlock</code></a>, then the caller should not treat |
| this as an error, but instead should wait until another readiness event is |
| received.</p> |
| <h4 id="draining-readiness"><a href="#draining-readiness">Draining readiness</a></h4> |
| <p>Once a readiness event is received, the corresponding operation must be |
| performed repeatedly until it returns <a href="https://doc.rust-lang.org/nightly/std/io/error/enum.ErrorKind.html#variant.WouldBlock"><code>WouldBlock</code></a>. Unless this is done, |
| there is no guarantee that another readiness event will be delivered, even |
| if further data is received for the event source.</p> |
| <h4 id="readiness-operations"><a href="#readiness-operations">Readiness operations</a></h4> |
| <p>The only readiness operations that are guaranteed to be present on all |
| supported platforms are <a href="./event/struct.Event.html#method.is_readable"><code>readable</code></a> and <a href="./event/struct.Event.html#method.is_writable"><code>writable</code></a>. All other readiness |
| operations may have false negatives and as such should be considered |
| <strong>hints</strong>. This means that if a socket is registered with <a href="./event/struct.Event.html#method.is_readable"><code>readable</code></a> |
| interest and either an error or close is received, a readiness event will |
| be generated for the socket, but it <strong>may</strong> only include <code>readable</code> |
| readiness. Also note that, given the potential for spurious events, |
| receiving a readiness event with <code>read_closed</code>, <code>write_closed</code>, or <code>error</code> |
| doesn’t actually mean that a <code>read</code> on the socket will return a result |
| matching the readiness event.</p> |
| <p>In other words, portable programs that explicitly check for <a href="./event/struct.Event.html#method.is_read_closed"><code>read_closed</code></a>, |
| <a href="./event/struct.Event.html#method.is_write_closed"><code>write_closed</code></a>, or <a href="./event/struct.Event.html#method.is_error"><code>error</code></a> readiness should be doing so as an |
| <strong>optimization</strong> and always be able to handle an error or close situation |
| when performing the actual read operation.</p> |
| <h4 id="registering-handles"><a href="#registering-handles">Registering handles</a></h4> |
| <p>Unless otherwise noted, it should be assumed that types implementing |
| <a href="./event/trait.Source.html"><code>event::Source</code></a> will never become ready unless they are registered with |
| <code>Poll</code>.</p> |
| <p>For example:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>mio::{Poll, Interest, Token}; |
| <span class="kw">use </span>mio::net::TcpStream; |
| <span class="kw">use </span>std::net::SocketAddr; |
| <span class="kw">use </span>std::time::Duration; |
| <span class="kw">use </span>std::thread; |
| |
| <span class="kw">let </span>address: SocketAddr = <span class="string">"127.0.0.1:0"</span>.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>listener = net::TcpListener::bind(address)<span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>sock = TcpStream::connect(listener.local_addr()<span class="question-mark">?</span>)<span class="question-mark">?</span>; |
| |
| thread::sleep(Duration::from_secs(<span class="number">1</span>)); |
| |
| <span class="kw">let </span>poll = Poll::new()<span class="question-mark">?</span>; |
| |
| <span class="comment">// The connect is not guaranteed to have started until it is registered at |
| // this point |
| </span>poll.registry().register(<span class="kw-2">&mut </span>sock, Token(<span class="number">0</span>), Interest::READABLE | Interest::WRITABLE)<span class="question-mark">?</span>;</code></pre></div> |
| <h4 id="dropping-poll"><a href="#dropping-poll">Dropping <code>Poll</code></a></h4> |
| <p>When the <code>Poll</code> instance is dropped it may cancel in-flight operations for |
| the registered <a href="./event/trait.Source.html">event sources</a>, meaning that no further events for them may |
| be received. It also means operations on the registered event sources may no |
| longer work. It is up to the user to keep the <code>Poll</code> instance alive while |
| registered event sources are being used.</p> |
| <h4 id="accessing-raw-fdsockethandle"><a href="#accessing-raw-fdsockethandle">Accessing raw fd/socket/handle</a></h4> |
| <p>Mio makes it possible for many types to be converted into a raw file |
| descriptor (fd, Unix), socket (Windows) or handle (Windows). This makes it |
| possible to support more operations on the type than Mio supports, for |
| example it makes <a href="https://github.com/asomers/mio-aio">mio-aio</a> possible. However accessing the raw fd is not |
| without it’s pitfalls.</p> |
| <p>Specifically performing I/O operations outside of Mio on these types (via |
| the raw fd) has unspecified behaviour. It could cause no more events to be |
| generated for the type even though it returned <code>WouldBlock</code> (in an operation |
| directly accessing the fd). The behaviour is OS specific and Mio can only |
| guarantee cross-platform behaviour if it can control the I/O.</p> |
| <p><em>The following is <strong>not</strong> guaranteed, just a description of the current |
| situation!</em> Mio is allowed to change the following without it being considered |
| a breaking change, don’t depend on this, it’s just here to inform the user. |
| Currently the kqueue and epoll implementation support direct I/O operations |
| on the fd without Mio’s knowledge. Windows however needs <strong>all</strong> I/O |
| operations to go through Mio otherwise it is not able to update it’s |
| internal state properly and won’t generate events.</p> |
| <h4 id="polling-without-registering-event-sources"><a href="#polling-without-registering-event-sources">Polling without registering event sources</a></h4> |
| <p><em>The following is <strong>not</strong> guaranteed, just a description of the current |
| situation!</em> Mio is allowed to change the following without it being |
| considered a breaking change, don’t depend on this, it’s just here to inform |
| the user. On platforms that use epoll, kqueue or IOCP (see implementation |
| notes below) polling without previously registering <a href="./event/trait.Source.html">event sources</a> will |
| result in sleeping forever, only a process signal will be able to wake up |
| the thread.</p> |
| <p>On WASM/WASI this is different as it doesn’t support process signals, |
| furthermore the WASI specification doesn’t specify a behaviour in this |
| situation, thus it’s up to the implementation what to do here. As an |
| example, the wasmtime runtime will return <code>EINVAL</code> in this situation, but |
| different runtimes may return different results. If you have further |
| insights or thoughts about this situation (and/or how Mio should handle it) |
| please add you comment to <a href="https://github.com/tokio-rs/mio/pull/1580">pull request#1580</a>.</p> |
| <h2 id="implementation-notes"><a href="#implementation-notes">Implementation notes</a></h2> |
| <p><code>Poll</code> is backed by the selector provided by the operating system.</p> |
| <div><table><thead><tr><th>OS</th><th>Selector</th></tr></thead><tbody> |
| <tr><td>Android</td><td><a href="https://man7.org/linux/man-pages/man7/epoll.7.html">epoll</a></td></tr> |
| <tr><td>DragonFly BSD</td><td><a href="https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2">kqueue</a></td></tr> |
| <tr><td>FreeBSD</td><td><a href="https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2">kqueue</a></td></tr> |
| <tr><td>iOS</td><td><a href="https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2">kqueue</a></td></tr> |
| <tr><td>illumos</td><td><a href="https://man7.org/linux/man-pages/man7/epoll.7.html">epoll</a></td></tr> |
| <tr><td>Linux</td><td><a href="https://man7.org/linux/man-pages/man7/epoll.7.html">epoll</a></td></tr> |
| <tr><td>NetBSD</td><td><a href="https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2">kqueue</a></td></tr> |
| <tr><td>OpenBSD</td><td><a href="https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2">kqueue</a></td></tr> |
| <tr><td>Windows</td><td><a href="https://docs.microsoft.com/en-us/windows/win32/fileio/i-o-completion-ports">IOCP</a></td></tr> |
| <tr><td>macOS</td><td><a href="https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2">kqueue</a></td></tr> |
| </tbody></table> |
| </div> |
| <p>On all supported platforms, socket operations are handled by using the |
| system selector. Platform specific extensions (e.g. <a href="unix/struct.SourceFd.html"><code>SourceFd</code></a>) allow |
| accessing other features provided by individual system selectors. For |
| example, Linux’s <a href="https://man7.org/linux/man-pages/man2/signalfd.2.html"><code>signalfd</code></a> feature can be used by registering the FD with |
| <code>Poll</code> via <a href="unix/struct.SourceFd.html"><code>SourceFd</code></a>.</p> |
| <p>On all platforms except windows, a call to <a href="struct.Poll.html#method.poll"><code>Poll::poll</code></a> is mostly just a |
| direct call to the system selector. However, <a href="https://docs.microsoft.com/en-us/windows/win32/fileio/i-o-completion-ports">IOCP</a> uses a completion model |
| instead of a readiness model. In this case, <code>Poll</code> must adapt the completion |
| model Mio’s API. While non-trivial, the bridge layer is still quite |
| efficient. The most expensive part being calls to <code>read</code> and <code>write</code> require |
| data to be copied into an intermediate buffer before it is passed to the |
| kernel.</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-Poll" class="impl has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#257-412">source</a><a href="#impl-Poll" class="anchor"></a><h3 class="code-header">impl <a class="struct" href="struct.Poll.html" title="struct mio::Poll">Poll</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.new" class="method has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#299-303">source</a><h4 class="code-header">pub fn <a href="#method.new" class="fnname">new</a>() -> <a class="type" href="https://doc.rust-lang.org/nightly/std/io/error/type.Result.html" title="type std::io::error::Result">Result</a><<a class="struct" href="struct.Poll.html" title="struct mio::Poll">Poll</a>></h4></section></summary><div class="docblock"><p>Return a new <code>Poll</code> handle.</p> |
| <p>This function will make a syscall to the operating system to create |
| the system selector. If this syscall fails, <code>Poll::new</code> will return |
| with the error.</p> |
| <p>close-on-exec flag is set on the file descriptors used by the selector to prevent |
| leaking it to executed processes. However, on some systems such as |
| old Linux systems that don’t support <code>epoll_create1</code> syscall it is done |
| non-atomically, so a separate thread executing in parallel to this |
| function may accidentally leak the file descriptor if it executes a |
| new process before this function returns.</p> |
| <p>See <a href="struct.Poll.html">struct</a> level docs for more details.</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>mio::{Poll, Events}; |
| <span class="kw">use </span>std::time::Duration; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>poll = <span class="kw">match </span>Poll::new() { |
| <span class="prelude-val">Ok</span>(poll) => poll, |
| <span class="prelude-val">Err</span>(e) => <span class="macro">panic!</span>(<span class="string">"failed to create Poll instance; err={:?}"</span>, e), |
| }; |
| |
| <span class="comment">// Create a structure to receive polled events |
| </span><span class="kw">let </span><span class="kw-2">mut </span>events = Events::with_capacity(<span class="number">1024</span>); |
| |
| <span class="comment">// Wait for events, but none will be received because no |
| // `event::Source`s have been registered with this `Poll` instance. |
| </span>poll.poll(<span class="kw-2">&mut </span>events, <span class="prelude-val">Some</span>(Duration::from_millis(<span class="number">500</span>)))<span class="question-mark">?</span>; |
| <span class="macro">assert!</span>(events.is_empty());</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.registry" class="method has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#308-310">source</a><h4 class="code-header">pub fn <a href="#method.registry" class="fnname">registry</a>(&self) -> &<a class="struct" href="struct.Registry.html" title="struct mio::Registry">Registry</a></h4></section></summary><div class="docblock"><p>Create a separate <code>Registry</code> which can be used to register |
| <code>event::Source</code>s.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.poll" class="method has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#409-411">source</a><h4 class="code-header">pub fn <a href="#method.poll" class="fnname">poll</a>(<br> &mut self,<br> events: &mut <a class="struct" href="event/struct.Events.html" title="struct mio::event::Events">Events</a>,<br> timeout: <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a><<a class="struct" href="https://doc.rust-lang.org/nightly/core/time/struct.Duration.html" title="struct core::time::Duration">Duration</a>><br>) -> <a class="type" href="https://doc.rust-lang.org/nightly/std/io/error/type.Result.html" title="type std::io::error::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>></h4></section></summary><div class="docblock"><p>Wait for readiness events</p> |
| <p>Blocks the current thread and waits for readiness events for any of the |
| <a href="./event/trait.Source.html"><code>event::Source</code></a>s that have been registered with this <code>Poll</code> instance. |
| The function will block until either at least one readiness event has |
| been received or <code>timeout</code> has elapsed. A <code>timeout</code> of <code>None</code> means that |
| <code>poll</code> will block until a readiness event has been received.</p> |
| <p>The supplied <code>events</code> will be cleared and newly received readiness events |
| will be pushed onto the end. At most <code>events.capacity()</code> events will be |
| returned. If there are further pending readiness events, they will be |
| returned on the next call to <code>poll</code>.</p> |
| <p>A single call to <code>poll</code> may result in multiple readiness events being |
| returned for a single event source. For example, if a TCP socket becomes |
| both readable and writable, it may be possible for a single readiness |
| event to be returned with both <a href="struct.Interest.html#associatedconstant.READABLE"><code>readable</code></a> and <a href="struct.Interest.html#associatedconstant.WRITABLE"><code>writable</code></a> readiness |
| <strong>OR</strong> two separate events may be returned, one with <a href="struct.Interest.html#associatedconstant.READABLE"><code>readable</code></a> set |
| and one with <a href="struct.Interest.html#associatedconstant.WRITABLE"><code>writable</code></a> set.</p> |
| <p>Note that the <code>timeout</code> will be rounded up to the system clock |
| granularity (usually 1ms), and kernel scheduling delays mean that |
| the blocking interval may be overrun by a small amount.</p> |
| <p>See the <a href="struct.Poll.html">struct</a> level documentation for a higher level discussion of |
| polling.</p> |
| <h5 id="notes"><a href="#notes">Notes</a></h5> |
| <p>This returns any errors without attempting to retry, previous versions |
| of Mio would automatically retry the poll call if it was interrupted |
| (if <code>EINTR</code> was returned).</p> |
| <p>Currently if the <code>timeout</code> elapses without any readiness events |
| triggering this will return <code>Ok(())</code>. However we’re not guaranteeing |
| this behaviour as this depends on the OS.</p> |
| <h5 id="examples-2"><a href="#examples-2">Examples</a></h5> |
| <p>A basic example – establishing a <code>TcpStream</code> connection.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>mio::{Events, Poll, Interest, Token}; |
| <span class="kw">use </span>mio::net::TcpStream; |
| |
| <span class="kw">use </span>std::net::{TcpListener, SocketAddr}; |
| <span class="kw">use </span>std::thread; |
| |
| <span class="comment">// Bind a server socket to connect to. |
| </span><span class="kw">let </span>addr: SocketAddr = <span class="string">"127.0.0.1:0"</span>.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>server = TcpListener::bind(addr)<span class="question-mark">?</span>; |
| <span class="kw">let </span>addr = server.local_addr()<span class="question-mark">?</span>.clone(); |
| |
| <span class="comment">// Spawn a thread to accept the socket |
| </span>thread::spawn(<span class="kw">move </span>|| { |
| <span class="kw">let _ </span>= server.accept(); |
| }); |
| |
| <span class="comment">// Construct a new `Poll` handle as well as the `Events` we'll store into |
| </span><span class="kw">let </span><span class="kw-2">mut </span>poll = Poll::new()<span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>events = Events::with_capacity(<span class="number">1024</span>); |
| |
| <span class="comment">// Connect the stream |
| </span><span class="kw">let </span><span class="kw-2">mut </span>stream = TcpStream::connect(addr)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Register the stream with `Poll` |
| </span>poll.registry().register( |
| <span class="kw-2">&mut </span>stream, |
| Token(<span class="number">0</span>), |
| Interest::READABLE | Interest::WRITABLE)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Wait for the socket to become ready. This has to happens in a loop to |
| // handle spurious wakeups. |
| </span><span class="kw">loop </span>{ |
| poll.poll(<span class="kw-2">&mut </span>events, <span class="prelude-val">None</span>)<span class="question-mark">?</span>; |
| |
| <span class="kw">for </span>event <span class="kw">in </span><span class="kw-2">&</span>events { |
| <span class="kw">if </span>event.token() == Token(<span class="number">0</span>) && event.is_writable() { |
| <span class="comment">// The socket connected (probably, it could still be a spurious |
| // wakeup) |
| </span><span class="kw">return </span><span class="prelude-val">Ok</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-AsRawFd-for-Poll" class="impl has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#415-419">source</a><a href="#impl-AsRawFd-for-Poll" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/std/os/fd/raw/trait.AsRawFd.html" title="trait std::os::fd::raw::AsRawFd">AsRawFd</a> for <a class="struct" href="struct.Poll.html" title="struct mio::Poll">Poll</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.as_raw_fd" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#416-418">source</a><a href="#method.as_raw_fd" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/std/os/fd/raw/trait.AsRawFd.html#tymethod.as_raw_fd" class="fnname">as_raw_fd</a>(&self) -> <a class="type" href="https://doc.rust-lang.org/nightly/std/os/fd/raw/type.RawFd.html" title="type std::os::fd::raw::RawFd">RawFd</a></h4></section></summary><div class='docblock'>Extracts the raw file descriptor. <a href="https://doc.rust-lang.org/nightly/std/os/fd/raw/trait.AsRawFd.html#tymethod.as_raw_fd">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Debug-for-Poll" class="impl has-srclink"><a class="srclink rightside" href="../src/mio/poll.rs.html#421-425">source</a><a href="#impl-Debug-for-Poll" 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.Poll.html" title="struct mio::Poll">Poll</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/mio/poll.rs.html#422-424">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, fmt: &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-Poll" class="impl has-srclink"><a href="#impl-RefUnwindSafe-for-Poll" 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.Poll.html" title="struct mio::Poll">Poll</a></h3></section><section id="impl-Send-for-Poll" class="impl has-srclink"><a href="#impl-Send-for-Poll" 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.Poll.html" title="struct mio::Poll">Poll</a></h3></section><section id="impl-Sync-for-Poll" class="impl has-srclink"><a href="#impl-Sync-for-Poll" 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.Poll.html" title="struct mio::Poll">Poll</a></h3></section><section id="impl-Unpin-for-Poll" class="impl has-srclink"><a href="#impl-Unpin-for-Poll" 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.Poll.html" title="struct mio::Poll">Poll</a></h3></section><section id="impl-UnwindSafe-for-Poll" class="impl has-srclink"><a href="#impl-UnwindSafe-for-Poll" 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.Poll.html" title="struct mio::Poll">Poll</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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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-Poll" 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="mio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
