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signals.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: 信号</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
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<body>
<div class="example" id="signals">
<h2><a href="./">Go by Example 中文版</a>: 信号</h2>
<table>
<tr>
<td class="docs">
<p>有时候，我们希望 Go 可以智能的处理 <a href="http://en.wikipedia.org/wiki/Unix_signal">Unix 信号</a>。
例如，我们希望当服务器接收到一个 <code>SIGTERM</code> 信号时，能够优雅退出，
或者一个命令行工具在接收到一个 <code>SIGINT</code> 信号时停止处理输入信息。
我们这里讲的就是在 Go 中如何使用通道来处理信号。</p>
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<td class="code empty leading">
</td>
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<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="https://play.studygolang.com/p/O1C4e597EpS"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
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<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kn">import</span> <span class="p">(</span>
<span class="s">"fmt"</span>
<span class="s">"os"</span>
<span class="s">"os/signal"</span>
<span class="s">"syscall"</span>
<span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>Go 通过向一个通道发送 <code>os.Signal</code> 值来发送信号通知。
我们将创建一个通道来接收这些通知。请注意，这个通道应该被缓存。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">sigs</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Signal</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>signal.Notify</code> 注册给定的通道，用于接收特定信号。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">signal</span><span class="p">.</span><span class="nf">Notify</span><span class="p">(</span><span class="nx">sigs</span><span class="p">,</span> <span class="nx">syscall</span><span class="p">.</span><span class="nx">SIGINT</span><span class="p">,</span> <span class="nx">syscall</span><span class="p">.</span><span class="nx">SIGTERM</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>我们可以在 main 函数中从 <code>sigs</code> 接收。
但让我们看看如何在单独的 goroutine 中完成此操作，
以演示更实际的正常关闭方案。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">done</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">bool</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>这个协程执行一个阻塞的信号接收操作。
当它接收到一个值时，它将打印这个值，然后通知程序可以退出。</p>
</td>
<td class="code leading">
<pre class="chroma"> <span class="k">go</span> <span class="kd">func</span><span class="p">()</span> <span class="p">{</span>
</pre>
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</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"> <span class="nx">sig</span> <span class="o">:=</span> <span class="o"><-</span><span class="nx">sigs</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">sig</span><span class="p">)</span>
<span class="nx">done</span> <span class="o"><-</span> <span class="kc">true</span>
<span class="p">}()</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<pre><code>程序将在这里进行等待，直到它得到了期望的信号
</code></pre>
<p>（也就是上面的协程发送的 <code>done</code> 值），然后退出。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"awaiting signal"</span><span class="p">)</span>
<span class="o"><-</span><span class="nx">done</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"exiting"</span><span class="p">)</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
<p>当我们运行这个程序时，它将一直等待一个信号。
通过 <code>ctrl-C</code>（终端显示为 <code>^C</code>），我们可以发送一个 <code>SIGINT</code> 信号，
这会使程序打印 <code>interrupt</code> 然后退出。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="gp">$</span> go run signals.go
<span class="go">awaiting signal
</span><span class="go">^C
</span><span class="go">interrupt
</span><span class="go">exiting</span></pre>
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="exit">退出</a>
</p>
<p class="footer">
<a href="https://twitter.com/mmcgrana">@mmcgrana</a> 和<a href="https://eli.thegreenplace.net">Eli Bendersky</a>编写 | <a href="https://github.com/gobyexample-cn">gobyexample-cn</a> 翻译 | <a href="https://github.com/gobyexample-cn/gobyexample/issues">反馈</a> | <a href="https://github.com/gobyexample-cn/gobyexample">源码</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> </p>
</p>
</div>
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codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"os\"\u000A \"os/signal\"\u000A \"syscall\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' sigs :\u003D make(chan os.Signal, 1)\u000A');codeLines.push(' signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)\u000A');codeLines.push(' done :\u003D make(chan bool, 1)\u000A');codeLines.push(' go func() {\u000A');codeLines.push(' sig :\u003D \u003C-sigs\u000A fmt.Println()\u000A fmt.Println(sig)\u000A done \u003C- true\u000A }()\u000A');codeLines.push(' fmt.Println(\"awaiting signal\")\u000A \u003C-done\u000A fmt.Println(\"exiting\")\u000A}\u000A');codeLines.push('');
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