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<p class='location'>Module timer</p><div class="sidebar-elems"><div class="block items"><ul><li><a href="#structs">Structs</a></li></ul></div><p class='location'><a href='../index.html'>tokio</a></p><script>window.sidebarCurrent = {name: 'timer', ty: 'mod', relpath: '../'};</script><script defer src="../sidebar-items.js"></script></div>
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<h1 class='fqn'><span class='in-band'>Module <a href='../index.html'>tokio</a>::<wbr><a class="mod" href=''>timer</a></span><span class='out-of-band'><span id='render-detail'>
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[<span class='inner'>&#x2212;</span>]
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</span><a class='srclink' href='../../src/tokio/timer.rs.html#1-86' title='goto source code'>[src]</a></span></h1>
<div class='docblock'><p>Utilities for tracking time.</p>
<p>This module provides a number of types for executing code after a set period
of time.</p>
<ul>
<li>
<p>[<code>Delay</code>][Delay] is a future that does no work and completes at a specific <code>Instant</code>
in time.</p>
</li>
<li>
<p>[<code>Interval</code>][Interval] is a stream yielding a value at a fixed period. It
is initialized with a <code>Duration</code> and repeatedly yields each time the
duration elapses.</p>
</li>
<li>
<p>[<code>Deadline</code>][Deadline] wraps a future, requiring that it completes before
a specified <code>Instant</code> in time. If the future does not complete in time,
then it is canceled and an error is returned.</p>
</li>
</ul>
<p>These types are sufficient for handling a large number of scenarios
involving time.</p>
<p>These types must be used from within the context of the
<a href="../runtime/struct.Runtime.html"><code>Runtime</code></a> or a timer context must be setup explicitly. See the
<a href="https://docs.rs/tokio-timer"><code>tokio-timer</code></a> crate for more details on how to setup a timer
context.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<p>Wait 100ms and print &quot;Hello World!&quot;</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">tokio</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="ident">tokio</span>::<span class="ident">timer</span>::<span class="ident">Delay</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">time</span>::{<span class="ident">Duration</span>, <span class="ident">Instant</span>};
<span class="kw">let</span> <span class="ident">when</span> <span class="op">=</span> <span class="ident">Instant</span>::<span class="ident">now</span>() <span class="op">+</span> <span class="ident">Duration</span>::<span class="ident">from_millis</span>(<span class="number">100</span>);
<span class="ident">tokio</span>::<span class="ident">run</span>({
<span class="ident">Delay</span>::<span class="ident">new</span>(<span class="ident">when</span>)
.<span class="ident">map_err</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> <span class="macro">panic</span><span class="macro">!</span>(<span class="string">&quot;timer failed; err={:?}&quot;</span>, <span class="ident">e</span>))
.<span class="ident">and_then</span>(<span class="op">|</span>_<span class="op">|</span> {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;Hello world!&quot;</span>);
<span class="prelude-val">Ok</span>(())
})
})</pre>
<p>Require that an operation takes no more than 300ms. Note that this uses the
<a href="../util/trait.FutureExt.html#method.deadline"><code>deadline</code></a> function on the <a href="../util/trait.FutureExt.html#method.deadline"><code>FutureExt</code></a> trait. This trait is
included in the prelude.</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">tokio</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">time</span>::{<span class="ident">Duration</span>, <span class="ident">Instant</span>};
<span class="kw">fn</span> <span class="ident">long_op</span>() <span class="op">-&gt;</span> <span class="ident">Box</span><span class="op">&lt;</span><span class="ident">Future</span><span class="op">&lt;</span><span class="ident">Item</span> <span class="op">=</span> (), <span class="ident">Error</span> <span class="op">=</span> ()<span class="op">&gt;</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">&gt;</span> {
<span class="comment">// ...</span>
}
<span class="kw">let</span> <span class="ident">when</span> <span class="op">=</span> <span class="ident">Instant</span>::<span class="ident">now</span>() <span class="op">+</span> <span class="ident">Duration</span>::<span class="ident">from_millis</span>(<span class="number">300</span>);
<span class="ident">tokio</span>::<span class="ident">run</span>({
<span class="ident">long_op</span>()
.<span class="ident">deadline</span>(<span class="ident">when</span>)
.<span class="ident">map_err</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;operation timed out&quot;</span>);
})
})</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.Deadline.html"
title='struct tokio::timer::Deadline'>Deadline</a></td>
<td class='docblock-short'>
<p>Allows a given <code>Future</code> to execute until the specified deadline.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.DeadlineError.html"
title='struct tokio::timer::DeadlineError'>DeadlineError</a></td>
<td class='docblock-short'>
<p>Error returned by <code>Deadline</code> future.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.Delay.html"
title='struct tokio::timer::Delay'>Delay</a></td>
<td class='docblock-short'>
<p>A future that completes at a specified instant in time.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.Error.html"
title='struct tokio::timer::Error'>Error</a></td>
<td class='docblock-short'>
<p>Errors encountered by the timer implementation.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.Interval.html"
title='struct tokio::timer::Interval'>Interval</a></td>
<td class='docblock-short'>
<p>A stream representing notifications at fixed interval</p>
</td>
</tr></table></section>
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