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<div class="example" id="channels">
<h2><a href="./">Go by Example</a>: Channels</h2>
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<p><em>Channels</em> are the pipes that connect concurrent
goroutines. You can send values into channels from one
goroutine and receive those values into another
goroutine.</p>
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<a href="http://play.golang.org/p/Kd8B0T_JGK"><img title="Run code" src="play.png" class="run" /></a>
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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<div class="highlight"><pre><span class="kn">import</span> <span class="s">"fmt"</span>
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
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<p>Create a new channel with <code>make(chan val-type)</code>.
Channels are typed by the values they convey.</p>
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<div class="highlight"><pre> <span class="nx">messages</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">string</span><span class="p">)</span>
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<p><em>Send</em> a value into a channel using the <code>channel <-</code>
syntax. Here we send <code>"ping"</code> to the <code>messages</code>
channel we made above, from a new goroutine.</p>
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<div class="highlight"><pre> <span class="k">go</span> <span class="kd">func</span><span class="p">()</span> <span class="p">{</span> <span class="nx">messages</span> <span class="o"><-</span> <span class="s">"ping"</span> <span class="p">}()</span>
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<p>The <code><-channel</code> syntax <em>receives</em> a value from the
channel. Here we’ll receive the <code>"ping"</code> message
we sent above and print it out.</p>
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<div class="highlight"><pre> <span class="nx">msg</span> <span class="o">:=</span> <span class="o"><-</span><span class="nx">messages</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">msg</span><span class="p">)</span>
<span class="p">}</span>
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<p>When we run the program the <code>"ping"</code> message is
successfully passed from one goroutine to another via
our channel.</p>
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<div class="highlight"><pre><span class="gp">$</span> go run channels.go
<span class="go">ping</span>
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<p>By default sends and receives block until both the
sender and receiver are ready. This property allowed
us to wait at the end of our program for the <code>"ping"</code>
message without having to use any other synchronization.</p>
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<p class="next">
Next example: <a href="channel-buffering">Channel Buffering</a>.
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by <a href="https://twitter.com/mmcgrana">@mmcgrana</a> | <a href="mailto:mmcgrana@gmail.com">feedback</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/channels">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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