mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-12-01 10:38:59 +00:00
2236 lines
84 KiB
HTML
2236 lines
84 KiB
HTML
<!DOCTYPE HTML>
|
|
<html lang="zh-tw" >
|
|
|
|
<head>
|
|
|
|
<meta charset="UTF-8">
|
|
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
|
|
<title>通過cgo調用C代碼 | Go编程语言</title>
|
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
|
<meta name="description" content="">
|
|
<meta name="generator" content="GitBook 2.5.2">
|
|
|
|
|
|
<meta name="HandheldFriendly" content="true"/>
|
|
<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
|
|
<meta name="apple-mobile-web-app-capable" content="yes">
|
|
<meta name="apple-mobile-web-app-status-bar-style" content="black">
|
|
<link rel="apple-touch-icon-precomposed" sizes="152x152" href="../gitbook/images/apple-touch-icon-precomposed-152.png">
|
|
<link rel="shortcut icon" href="../gitbook/images/favicon.ico" type="image/x-icon">
|
|
|
|
<link rel="stylesheet" href="../gitbook/style.css">
|
|
|
|
|
|
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-highlight/website.css">
|
|
|
|
|
|
|
|
<link rel="stylesheet" href="../gitbook/plugins/gitbook-plugin-fontsettings/website.css">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<link rel="next" href="../ch13/ch13-05.html" />
|
|
|
|
|
|
<link rel="prev" href="../ch13/ch13-03.html" />
|
|
|
|
|
|
|
|
</head>
|
|
<body>
|
|
|
|
|
|
<div class="book" data-level="13.4" data-chapter-title="通過cgo調用C代碼" data-filepath="ch13/ch13-04.md" data-basepath=".." data-revision="Fri Dec 25 2015 12:32:44 GMT+0800 (中国标准时间)">
|
|
|
|
|
|
<div class="book-summary">
|
|
<nav role="navigation">
|
|
<ul class="summary">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<li class="chapter " data-level="0" data-path="index.html">
|
|
|
|
|
|
<a href="../index.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
前言
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="0.1" data-path="ch0/ch0-01.html">
|
|
|
|
|
|
<a href="../ch0/ch0-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.1.</b>
|
|
|
|
Go語言起源
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.2" data-path="ch0/ch0-02.html">
|
|
|
|
|
|
<a href="../ch0/ch0-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.2.</b>
|
|
|
|
Go語言項目
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.3" data-path="ch0/ch0-03.html">
|
|
|
|
|
|
<a href="../ch0/ch0-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.3.</b>
|
|
|
|
本書的組織
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.4" data-path="ch0/ch0-04.html">
|
|
|
|
|
|
<a href="../ch0/ch0-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.4.</b>
|
|
|
|
更多的信息
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="0.5" data-path="ch0/ch0-05.html">
|
|
|
|
|
|
<a href="../ch0/ch0-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>0.5.</b>
|
|
|
|
致謝
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1" data-path="ch1/ch1.html">
|
|
|
|
|
|
<a href="../ch1/ch1.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.</b>
|
|
|
|
入門
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="1.1" data-path="ch1/ch1-01.html">
|
|
|
|
|
|
<a href="../ch1/ch1-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.1.</b>
|
|
|
|
Hello, World
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.2" data-path="ch1/ch1-02.html">
|
|
|
|
|
|
<a href="../ch1/ch1-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.2.</b>
|
|
|
|
命令行參數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.3" data-path="ch1/ch1-03.html">
|
|
|
|
|
|
<a href="../ch1/ch1-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.3.</b>
|
|
|
|
査找重複的行
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.4" data-path="ch1/ch1-04.html">
|
|
|
|
|
|
<a href="../ch1/ch1-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.4.</b>
|
|
|
|
GIF動畵
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.5" data-path="ch1/ch1-05.html">
|
|
|
|
|
|
<a href="../ch1/ch1-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.5.</b>
|
|
|
|
穫取URL
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.6" data-path="ch1/ch1-06.html">
|
|
|
|
|
|
<a href="../ch1/ch1-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.6.</b>
|
|
|
|
併發穫取多個URL
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.7" data-path="ch1/ch1-07.html">
|
|
|
|
|
|
<a href="../ch1/ch1-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.7.</b>
|
|
|
|
Web服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="1.8" data-path="ch1/ch1-08.html">
|
|
|
|
|
|
<a href="../ch1/ch1-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>1.8.</b>
|
|
|
|
本章要點
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2" data-path="ch2/ch2.html">
|
|
|
|
|
|
<a href="../ch2/ch2.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.</b>
|
|
|
|
程序結構
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="2.1" data-path="ch2/ch2-01.html">
|
|
|
|
|
|
<a href="../ch2/ch2-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.1.</b>
|
|
|
|
命名
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.2" data-path="ch2/ch2-02.html">
|
|
|
|
|
|
<a href="../ch2/ch2-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.2.</b>
|
|
|
|
聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.3" data-path="ch2/ch2-03.html">
|
|
|
|
|
|
<a href="../ch2/ch2-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.3.</b>
|
|
|
|
變量
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.4" data-path="ch2/ch2-04.html">
|
|
|
|
|
|
<a href="../ch2/ch2-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.4.</b>
|
|
|
|
賦值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.5" data-path="ch2/ch2-05.html">
|
|
|
|
|
|
<a href="../ch2/ch2-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.5.</b>
|
|
|
|
類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.6" data-path="ch2/ch2-06.html">
|
|
|
|
|
|
<a href="../ch2/ch2-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.6.</b>
|
|
|
|
包和文件
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="2.7" data-path="ch2/ch2-07.html">
|
|
|
|
|
|
<a href="../ch2/ch2-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>2.7.</b>
|
|
|
|
作用域
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3" data-path="ch3/ch3.html">
|
|
|
|
|
|
<a href="../ch3/ch3.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.</b>
|
|
|
|
基礎數據類型
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="3.1" data-path="ch3/ch3-01.html">
|
|
|
|
|
|
<a href="../ch3/ch3-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.1.</b>
|
|
|
|
整型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.2" data-path="ch3/ch3-02.html">
|
|
|
|
|
|
<a href="../ch3/ch3-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.2.</b>
|
|
|
|
浮點數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.3" data-path="ch3/ch3-03.html">
|
|
|
|
|
|
<a href="../ch3/ch3-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.3.</b>
|
|
|
|
複數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.4" data-path="ch3/ch3-04.html">
|
|
|
|
|
|
<a href="../ch3/ch3-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.4.</b>
|
|
|
|
布爾型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.5" data-path="ch3/ch3-05.html">
|
|
|
|
|
|
<a href="../ch3/ch3-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.5.</b>
|
|
|
|
字符串
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="3.6" data-path="ch3/ch3-06.html">
|
|
|
|
|
|
<a href="../ch3/ch3-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>3.6.</b>
|
|
|
|
常量
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4" data-path="ch4/ch4.html">
|
|
|
|
|
|
<a href="../ch4/ch4.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.</b>
|
|
|
|
複合數據類型
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="4.1" data-path="ch4/ch4-01.html">
|
|
|
|
|
|
<a href="../ch4/ch4-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.1.</b>
|
|
|
|
數組
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.2" data-path="ch4/ch4-02.html">
|
|
|
|
|
|
<a href="../ch4/ch4-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.2.</b>
|
|
|
|
切片
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.3" data-path="ch4/ch4-03.html">
|
|
|
|
|
|
<a href="../ch4/ch4-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.3.</b>
|
|
|
|
字典
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.4" data-path="ch4/ch4-04.html">
|
|
|
|
|
|
<a href="../ch4/ch4-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.4.</b>
|
|
|
|
結構體
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.5" data-path="ch4/ch4-05.html">
|
|
|
|
|
|
<a href="../ch4/ch4-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.5.</b>
|
|
|
|
JSON
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="4.6" data-path="ch4/ch4-06.html">
|
|
|
|
|
|
<a href="../ch4/ch4-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>4.6.</b>
|
|
|
|
文本和HTML模闆
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5" data-path="ch5/ch5.html">
|
|
|
|
|
|
<a href="../ch5/ch5.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.</b>
|
|
|
|
函數
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="5.1" data-path="ch5/ch5-01.html">
|
|
|
|
|
|
<a href="../ch5/ch5-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.1.</b>
|
|
|
|
函數聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.2" data-path="ch5/ch5-02.html">
|
|
|
|
|
|
<a href="../ch5/ch5-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.2.</b>
|
|
|
|
遞歸
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.3" data-path="ch5/ch5-03.html">
|
|
|
|
|
|
<a href="../ch5/ch5-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.3.</b>
|
|
|
|
多返迴值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.4" data-path="ch5/ch5-04.html">
|
|
|
|
|
|
<a href="../ch5/ch5-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.4.</b>
|
|
|
|
錯誤
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.5" data-path="ch5/ch5-05.html">
|
|
|
|
|
|
<a href="../ch5/ch5-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.5.</b>
|
|
|
|
函數值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.6" data-path="ch5/ch5-06.html">
|
|
|
|
|
|
<a href="../ch5/ch5-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.6.</b>
|
|
|
|
匿名函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.7" data-path="ch5/ch5-07.html">
|
|
|
|
|
|
<a href="../ch5/ch5-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.7.</b>
|
|
|
|
可變參數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.8" data-path="ch5/ch5-08.html">
|
|
|
|
|
|
<a href="../ch5/ch5-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.8.</b>
|
|
|
|
Deferred函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.9" data-path="ch5/ch5-09.html">
|
|
|
|
|
|
<a href="../ch5/ch5-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.9.</b>
|
|
|
|
Panic異常
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="5.10" data-path="ch5/ch5-10.html">
|
|
|
|
|
|
<a href="../ch5/ch5-10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>5.10.</b>
|
|
|
|
Recover捕穫異常
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6" data-path="ch6/ch6.html">
|
|
|
|
|
|
<a href="../ch6/ch6.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.</b>
|
|
|
|
方法
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="6.1" data-path="ch6/ch6-01.html">
|
|
|
|
|
|
<a href="../ch6/ch6-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.1.</b>
|
|
|
|
方法聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.2" data-path="ch6/ch6-02.html">
|
|
|
|
|
|
<a href="../ch6/ch6-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.2.</b>
|
|
|
|
基於指針對象的方法
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.3" data-path="ch6/ch6-03.html">
|
|
|
|
|
|
<a href="../ch6/ch6-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.3.</b>
|
|
|
|
通過嵌入結構體來擴展類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.4" data-path="ch6/ch6-04.html">
|
|
|
|
|
|
<a href="../ch6/ch6-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.4.</b>
|
|
|
|
方法值和方法表達式
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.5" data-path="ch6/ch6-05.html">
|
|
|
|
|
|
<a href="../ch6/ch6-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.5.</b>
|
|
|
|
示例: Bit數組
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="6.6" data-path="ch6/ch6-06.html">
|
|
|
|
|
|
<a href="../ch6/ch6-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>6.6.</b>
|
|
|
|
封裝
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7" data-path="ch7/ch7.html">
|
|
|
|
|
|
<a href="../ch7/ch7.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.</b>
|
|
|
|
接口
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="7.1" data-path="ch7/ch7-01.html">
|
|
|
|
|
|
<a href="../ch7/ch7-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.1.</b>
|
|
|
|
接口是合約
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.2" data-path="ch7/ch7-02.html">
|
|
|
|
|
|
<a href="../ch7/ch7-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.2.</b>
|
|
|
|
接口類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.3" data-path="ch7/ch7-03.html">
|
|
|
|
|
|
<a href="../ch7/ch7-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.3.</b>
|
|
|
|
實現接口的條件
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.4" data-path="ch7/ch7-04.html">
|
|
|
|
|
|
<a href="../ch7/ch7-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.4.</b>
|
|
|
|
flag.Value接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.5" data-path="ch7/ch7-05.html">
|
|
|
|
|
|
<a href="../ch7/ch7-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.5.</b>
|
|
|
|
接口值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.6" data-path="ch7/ch7-06.html">
|
|
|
|
|
|
<a href="../ch7/ch7-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.6.</b>
|
|
|
|
sort.Interface接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.7" data-path="ch7/ch7-07.html">
|
|
|
|
|
|
<a href="../ch7/ch7-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.7.</b>
|
|
|
|
http.Handler接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.8" data-path="ch7/ch7-08.html">
|
|
|
|
|
|
<a href="../ch7/ch7-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.8.</b>
|
|
|
|
error接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.9" data-path="ch7/ch7-09.html">
|
|
|
|
|
|
<a href="../ch7/ch7-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.9.</b>
|
|
|
|
示例: 表達式求值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.10" data-path="ch7/ch7-10.html">
|
|
|
|
|
|
<a href="../ch7/ch7-10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.10.</b>
|
|
|
|
類型斷言
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.11" data-path="ch7/ch7-11.html">
|
|
|
|
|
|
<a href="../ch7/ch7-11.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.11.</b>
|
|
|
|
基於類型斷言識别錯誤類型
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.12" data-path="ch7/ch7-12.html">
|
|
|
|
|
|
<a href="../ch7/ch7-12.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.12.</b>
|
|
|
|
通過類型斷言査詢接口
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.13" data-path="ch7/ch7-13.html">
|
|
|
|
|
|
<a href="../ch7/ch7-13.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.13.</b>
|
|
|
|
類型分支
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.14" data-path="ch7/ch7-14.html">
|
|
|
|
|
|
<a href="../ch7/ch7-14.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.14.</b>
|
|
|
|
示例: 基於標記的XML解碼
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="7.15" data-path="ch7/ch7-15.html">
|
|
|
|
|
|
<a href="../ch7/ch7-15.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>7.15.</b>
|
|
|
|
補充幾點
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8" data-path="ch8/ch8.html">
|
|
|
|
|
|
<a href="../ch8/ch8.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.</b>
|
|
|
|
Goroutines和Channels
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="8.1" data-path="ch8/ch8-01.html">
|
|
|
|
|
|
<a href="../ch8/ch8-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.1.</b>
|
|
|
|
Goroutines
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.2" data-path="ch8/ch8-02.html">
|
|
|
|
|
|
<a href="../ch8/ch8-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.2.</b>
|
|
|
|
示例: 併發的Clock服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.3" data-path="ch8/ch8-03.html">
|
|
|
|
|
|
<a href="../ch8/ch8-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.3.</b>
|
|
|
|
示例: 併發的Echo服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.4" data-path="ch8/ch8-04.html">
|
|
|
|
|
|
<a href="../ch8/ch8-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.4.</b>
|
|
|
|
Channels
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.5" data-path="ch8/ch8-05.html">
|
|
|
|
|
|
<a href="../ch8/ch8-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.5.</b>
|
|
|
|
併行的循環
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.6" data-path="ch8/ch8-06.html">
|
|
|
|
|
|
<a href="../ch8/ch8-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.6.</b>
|
|
|
|
示例: 併發的Web爬蟲
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.7" data-path="ch8/ch8-07.html">
|
|
|
|
|
|
<a href="../ch8/ch8-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.7.</b>
|
|
|
|
基於select的多路複用
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.8" data-path="ch8/ch8-08.html">
|
|
|
|
|
|
<a href="../ch8/ch8-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.8.</b>
|
|
|
|
示例: 併發的字典遍歷
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.9" data-path="ch8/ch8-09.html">
|
|
|
|
|
|
<a href="../ch8/ch8-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.9.</b>
|
|
|
|
併發的退齣
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="8.10" data-path="ch8/ch8-10.html">
|
|
|
|
|
|
<a href="../ch8/ch8-10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>8.10.</b>
|
|
|
|
示例: 聊天服務
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9" data-path="ch9/ch9.html">
|
|
|
|
|
|
<a href="../ch9/ch9.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.</b>
|
|
|
|
基於共享變量的併發
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="9.1" data-path="ch9/ch9-01.html">
|
|
|
|
|
|
<a href="../ch9/ch9-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.1.</b>
|
|
|
|
競爭條件
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.2" data-path="ch9/ch9-02.html">
|
|
|
|
|
|
<a href="../ch9/ch9-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.2.</b>
|
|
|
|
sync.Mutex互斥鎖
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.3" data-path="ch9/ch9-03.html">
|
|
|
|
|
|
<a href="../ch9/ch9-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.3.</b>
|
|
|
|
sync.RWMutex讀寫鎖
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.4" data-path="ch9/ch9-04.html">
|
|
|
|
|
|
<a href="../ch9/ch9-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.4.</b>
|
|
|
|
內存同步
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.5" data-path="ch9/ch9-05.html">
|
|
|
|
|
|
<a href="../ch9/ch9-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.5.</b>
|
|
|
|
sync.Once初始化
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.6" data-path="ch9/ch9-06.html">
|
|
|
|
|
|
<a href="../ch9/ch9-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.6.</b>
|
|
|
|
競爭條件檢測
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.7" data-path="ch9/ch9-07.html">
|
|
|
|
|
|
<a href="../ch9/ch9-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.7.</b>
|
|
|
|
示例: 併發的非阻塞緩存
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="9.8" data-path="ch9/ch9-08.html">
|
|
|
|
|
|
<a href="../ch9/ch9-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>9.8.</b>
|
|
|
|
Goroutines和線程
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10" data-path="ch10/ch10.html">
|
|
|
|
|
|
<a href="../ch10/ch10.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.</b>
|
|
|
|
包和工具
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="10.1" data-path="ch10/ch10-01.html">
|
|
|
|
|
|
<a href="../ch10/ch10-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.1.</b>
|
|
|
|
簡介
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.2" data-path="ch10/ch10-02.html">
|
|
|
|
|
|
<a href="../ch10/ch10-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.2.</b>
|
|
|
|
導入路徑
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.3" data-path="ch10/ch10-03.html">
|
|
|
|
|
|
<a href="../ch10/ch10-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.3.</b>
|
|
|
|
包聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.4" data-path="ch10/ch10-04.html">
|
|
|
|
|
|
<a href="../ch10/ch10-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.4.</b>
|
|
|
|
導入聲明
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.5" data-path="ch10/ch10-05.html">
|
|
|
|
|
|
<a href="../ch10/ch10-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.5.</b>
|
|
|
|
匿名導入
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.6" data-path="ch10/ch10-06.html">
|
|
|
|
|
|
<a href="../ch10/ch10-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.6.</b>
|
|
|
|
包和命名
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="10.7" data-path="ch10/ch10-07.html">
|
|
|
|
|
|
<a href="../ch10/ch10-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>10.7.</b>
|
|
|
|
工具
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11" data-path="ch11/ch11.html">
|
|
|
|
|
|
<a href="../ch11/ch11.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.</b>
|
|
|
|
測試
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="11.1" data-path="ch11/ch11-01.html">
|
|
|
|
|
|
<a href="../ch11/ch11-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.1.</b>
|
|
|
|
go test
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.2" data-path="ch11/ch11-02.html">
|
|
|
|
|
|
<a href="../ch11/ch11-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.2.</b>
|
|
|
|
測試函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.3" data-path="ch11/ch11-03.html">
|
|
|
|
|
|
<a href="../ch11/ch11-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.3.</b>
|
|
|
|
測試覆蓋率
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.4" data-path="ch11/ch11-04.html">
|
|
|
|
|
|
<a href="../ch11/ch11-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.4.</b>
|
|
|
|
基準測試
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.5" data-path="ch11/ch11-05.html">
|
|
|
|
|
|
<a href="../ch11/ch11-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.5.</b>
|
|
|
|
剖析
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="11.6" data-path="ch11/ch11-06.html">
|
|
|
|
|
|
<a href="../ch11/ch11-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>11.6.</b>
|
|
|
|
示例函數
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12" data-path="ch12/ch12.html">
|
|
|
|
|
|
<a href="../ch12/ch12.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.</b>
|
|
|
|
反射
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="12.1" data-path="ch12/ch12-01.html">
|
|
|
|
|
|
<a href="../ch12/ch12-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.1.</b>
|
|
|
|
爲何需要反射?
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.2" data-path="ch12/ch12-02.html">
|
|
|
|
|
|
<a href="../ch12/ch12-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.2.</b>
|
|
|
|
reflect.Type和reflect.Value
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.3" data-path="ch12/ch12-03.html">
|
|
|
|
|
|
<a href="../ch12/ch12-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.3.</b>
|
|
|
|
Display遞歸打印
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.4" data-path="ch12/ch12-04.html">
|
|
|
|
|
|
<a href="../ch12/ch12-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.4.</b>
|
|
|
|
示例: 編碼S表達式
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.5" data-path="ch12/ch12-05.html">
|
|
|
|
|
|
<a href="../ch12/ch12-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.5.</b>
|
|
|
|
通過reflect.Value脩改值
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.6" data-path="ch12/ch12-06.html">
|
|
|
|
|
|
<a href="../ch12/ch12-06.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.6.</b>
|
|
|
|
示例: 解碼S表達式
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.7" data-path="ch12/ch12-07.html">
|
|
|
|
|
|
<a href="../ch12/ch12-07.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.7.</b>
|
|
|
|
穫取結構體字段標識
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.8" data-path="ch12/ch12-08.html">
|
|
|
|
|
|
<a href="../ch12/ch12-08.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.8.</b>
|
|
|
|
顯示一個類型的方法集
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="12.9" data-path="ch12/ch12-09.html">
|
|
|
|
|
|
<a href="../ch12/ch12-09.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>12.9.</b>
|
|
|
|
幾點忠告
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13" data-path="ch13/ch13.html">
|
|
|
|
|
|
<a href="../ch13/ch13.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.</b>
|
|
|
|
底層編程
|
|
</a>
|
|
|
|
|
|
<ul class="articles">
|
|
|
|
|
|
<li class="chapter " data-level="13.1" data-path="ch13/ch13-01.html">
|
|
|
|
|
|
<a href="../ch13/ch13-01.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.1.</b>
|
|
|
|
unsafe.Sizeof, Alignof 和 Offsetof
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.2" data-path="ch13/ch13-02.html">
|
|
|
|
|
|
<a href="../ch13/ch13-02.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.2.</b>
|
|
|
|
unsafe.Pointer
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.3" data-path="ch13/ch13-03.html">
|
|
|
|
|
|
<a href="../ch13/ch13-03.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.3.</b>
|
|
|
|
示例: 深度相等判斷
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter active" data-level="13.4" data-path="ch13/ch13-04.html">
|
|
|
|
|
|
<a href="../ch13/ch13-04.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.4.</b>
|
|
|
|
通過cgo調用C代碼
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="13.5" data-path="ch13/ch13-05.html">
|
|
|
|
|
|
<a href="../ch13/ch13-05.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>13.5.</b>
|
|
|
|
幾點忠告
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
</li>
|
|
|
|
<li class="chapter " data-level="14" data-path="CONTRIBUTORS.html">
|
|
|
|
|
|
<a href="../CONTRIBUTORS.html">
|
|
|
|
<i class="fa fa-check"></i>
|
|
|
|
<b>14.</b>
|
|
|
|
附録
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
|
|
|
|
<li class="divider"></li>
|
|
<li>
|
|
<a href="https://www.gitbook.com" target="blank" class="gitbook-link">
|
|
本書使用 GitBook 釋出
|
|
</a>
|
|
</li>
|
|
|
|
</ul>
|
|
</nav>
|
|
</div>
|
|
|
|
<div class="book-body">
|
|
<div class="body-inner">
|
|
<div class="book-header" role="navigation">
|
|
<!-- Actions Left -->
|
|
|
|
|
|
<!-- Title -->
|
|
<h1>
|
|
<i class="fa fa-circle-o-notch fa-spin"></i>
|
|
<a href="../" >Go编程语言</a>
|
|
</h1>
|
|
</div>
|
|
|
|
<div class="page-wrapper" tabindex="-1" role="main">
|
|
<div class="page-inner">
|
|
|
|
|
|
<section class="normal" id="section-">
|
|
|
|
<h2 id="134-通過cgo調用c代碼">13.4. 通過cgo調用C代碼</h2>
|
|
<p>Go程序可能會遇到要訪問C語言的某些硬件驅動函數的場景，或者是從一個C++語言實現的嵌入式數據庫査詢記録的場景，或者是使用Fortran語言實現的一些線性代數庫的場景。C語言作爲一個通用語言，很多庫會選擇提供一個C兼容的API，然後用其他不同的編程語言實現（譯者：Go語言需要也應該擁抱這些鉅大的代碼遺産）。</p>
|
|
<p>在本節中，我們將構建一個簡易的數據壓縮程序，使用了一個Go語言自帶的叫cgo的用於支援C語言函數調用的工具。這類工具一般被稱爲 <em>foreign-function interfaces</em> （簡稱ffi）, 併且在類似工具中cgo也不是唯一的。SWIG（ <a href="http://swig.org" target="_blank">http://swig.org</a> ）是另一個類似的且被廣泛使用的工具，SWIG提供了很多複雜特性以支援C++的特性，但SWIG併不是我們要討論的主題。</p>
|
|
<p>在標準庫的<code>compress/...</code>子包有很多流行的壓縮算法的編碼和解碼實現，包括流行的LZW壓縮算法（Unix的compress命令用的算法）和DEFLATE壓縮算法（GNU gzip命令用的算法）。這些包的API的細節雖然有些差異，但是它們都提供了針對 io.Writer類型輸齣的壓縮接口和提供了針對io.Reader類型輸入的解壓縮接口。例如：</p>
|
|
<pre><code class="lang-Go"><span class="hljs-keyword">package</span> gzip <span class="hljs-comment">// compress/gzip</span>
|
|
<span class="hljs-keyword">func</span> NewWriter(w io.Writer) io.WriteCloser
|
|
<span class="hljs-keyword">func</span> NewReader(r io.Reader) (io.ReadCloser, error)
|
|
</code></pre>
|
|
<p>bzip2壓縮算法，是基於優雅的Burrows-Wheeler變換算法，運行速度比gzip要慢，但是可以提供更高的壓縮比。標準庫的compress/bzip2包目前還沒有提供bzip2壓縮算法的實現。完全從頭開始實現是一個壓縮算法是一件繁瑣的工作，而且 <a href="http://bzip.org" target="_blank">http://bzip.org</a> 已經有現成的libbzip2的開源實現，不僅文檔齊全而且性能又好。</p>
|
|
<p>如果是比較小的C語言庫，我們完全可以用純Go語言重新實現一遍。如果我們對性能也沒有特殊要求的話，我們還可以用os/exec包的方法將C編寫的應用程序作爲一個子進程運行。隻有當你需要使用複雜而且性能更高的底層C接口時，就是使用cgo的場景了（譯註：用os/exec包調用子進程的方法會導致程序運行時依賴那個應用程序）。下面我們將通過一個例子講述cgo的具體用法。</p>
|
|
<p>譯註：本章采用的代碼都是最新的。因爲之前已經齣版的書中包含的代碼隻能在Go1.5之前使用。從Go1.6開始，Go語言已經明確規定了哪些Go語言指針可以之間傳入C語言函數。新代碼重點是增加了bz2alloc和bz2free的兩個函數，用於bz_stream對象空間的申請和釋放操作。下面是新代碼中增加的註釋，説明這個問題：</p>
|
|
<pre><code class="lang-Go"><span class="hljs-comment">// The version of this program that appeared in the first and second</span>
|
|
<span class="hljs-comment">// printings did not comply with the proposed rules for passing</span>
|
|
<span class="hljs-comment">// pointers between Go and C, described here:</span>
|
|
<span class="hljs-comment">// https://github.com/golang/proposal/blob/master/design/12416-cgo-pointers.md</span>
|
|
<span class="hljs-comment">//</span>
|
|
<span class="hljs-comment">// The rules forbid a C function like bz2compress from storing 'in'</span>
|
|
<span class="hljs-comment">// and 'out' (pointers to variables allocated by Go) into the Go</span>
|
|
<span class="hljs-comment">// variable 's', even temporarily.</span>
|
|
<span class="hljs-comment">//</span>
|
|
<span class="hljs-comment">// The version below, which appears in the third printing, has been</span>
|
|
<span class="hljs-comment">// corrected. To comply with the rules, the bz_stream variable must</span>
|
|
<span class="hljs-comment">// be allocated by C code. We have introduced two C functions,</span>
|
|
<span class="hljs-comment">// bz2alloc and bz2free, to allocate and free instances of the</span>
|
|
<span class="hljs-comment">// bz_stream type. Also, we have changed bz2compress so that before</span>
|
|
<span class="hljs-comment">// it returns, it clears the fields of the bz_stream that contain</span>
|
|
<span class="hljs-comment">// pointers to Go variables.</span>
|
|
</code></pre>
|
|
<p>要使用libbzip2，我們需要先構建一個bz_stream結構體，用於保持輸入和輸齣緩存。然後有三個函數：BZ2_bzCompressInit用於初始化緩存，BZ2_bzCompress用於將輸入緩存的數據壓縮到輸齣緩存，BZ2_bzCompressEnd用於釋放不需要的緩存。（目前不要擔心包的具體結構, 這個例子的目的就是演示各個部分如何組合在一起的。）</p>
|
|
<p>我們可以在Go代碼中直接調用BZ2_bzCompressInit和BZ2_bzCompressEnd，但是對於BZ2_bzCompress，我們將定義一個C語言的包裝函數，用它完成眞正的工作。下面是C代碼，對應一個獨立的文件。</p>
|
|
<pre><code class="lang-C">gopl.io/ch13/bzip
|
|
|
|
<span class="hljs-comment">/* This file is gopl.io/ch13/bzip/bzip2.c, */</span>
|
|
<span class="hljs-comment">/* a simple wrapper for libbzip2 suitable for cgo. */</span>
|
|
<span class="hljs-preprocessor">#<span class="hljs-keyword">include</span> <span class="hljs-string"><bzlib.h></span></span>
|
|
|
|
<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">bz2compress</span><span class="hljs-params">(bz_stream *s, <span class="hljs-keyword">int</span> action,
|
|
<span class="hljs-keyword">char</span> *in, <span class="hljs-keyword">unsigned</span> *inlen, <span class="hljs-keyword">char</span> *out, <span class="hljs-keyword">unsigned</span> *outlen)</span> </span>{
|
|
s->next_in = in;
|
|
s->avail_in = *inlen;
|
|
s->next_out = out;
|
|
s->avail_out = *outlen;
|
|
<span class="hljs-keyword">int</span> r = BZ2_bzCompress(s, action);
|
|
*inlen -= s->avail_in;
|
|
*outlen -= s->avail_out;
|
|
s->next_in = s->next_out = <span class="hljs-literal">NULL</span>;
|
|
<span class="hljs-keyword">return</span> r;
|
|
}
|
|
</code></pre>
|
|
<p>現在讓我們轉到Go語言部分，第一部分如下所示。其中<code>import "C"</code>的語句是比較特别的。其實併沒有一個叫C的包，但是這行語句會讓Go編譯程序在編譯之前先運行cgo工具。</p>
|
|
<pre><code class="lang-Go"><span class="hljs-comment">// Package bzip provides a writer that uses bzip2 compression (bzip.org).</span>
|
|
<span class="hljs-keyword">package</span> bzip
|
|
|
|
<span class="hljs-comment">/*
|
|
#cgo CFLAGS: -I/usr/include
|
|
#cgo LDFLAGS: -L/usr/lib -lbz2
|
|
#include <bzlib.h>
|
|
#include <stdlib.h>
|
|
bz_stream* bz2alloc() { return calloc(1, sizeof(bz_stream)); }
|
|
int bz2compress(bz_stream *s, int action,
|
|
char *in, unsigned *inlen, char *out, unsigned *outlen);
|
|
void bz2free(bz_stream* s) { free(s); }
|
|
*/</span>
|
|
<span class="hljs-keyword">import</span> <span class="hljs-string">"C"</span>
|
|
|
|
<span class="hljs-keyword">import</span> (
|
|
<span class="hljs-string">"io"</span>
|
|
<span class="hljs-string">"unsafe"</span>
|
|
)
|
|
|
|
<span class="hljs-keyword">type</span> writer <span class="hljs-keyword">struct</span> {
|
|
w io.Writer <span class="hljs-comment">// underlying output stream</span>
|
|
stream *C.bz_stream
|
|
outbuf [<span class="hljs-number">64</span> * <span class="hljs-number">1024</span>]<span class="hljs-typename">byte</span>
|
|
}
|
|
|
|
<span class="hljs-comment">// NewWriter returns a writer for bzip2-compressed streams.</span>
|
|
<span class="hljs-keyword">func</span> NewWriter(out io.Writer) io.WriteCloser {
|
|
<span class="hljs-keyword">const</span> blockSize = <span class="hljs-number">9</span>
|
|
<span class="hljs-keyword">const</span> verbosity = <span class="hljs-number">0</span>
|
|
<span class="hljs-keyword">const</span> workFactor = <span class="hljs-number">30</span>
|
|
w := &writer{w: out, stream: C.bz2alloc()}
|
|
C.BZ2_bzCompressInit(w.stream, blockSize, verbosity, workFactor)
|
|
<span class="hljs-keyword">return</span> w
|
|
}
|
|
</code></pre>
|
|
<p>在預處理過程中，cgo工具爲生成一個臨時包用於包含所有在Go語言中訪問的C語言的函數或類型。例如C.bz_stream和C.BZ2_bzCompressInit。cgo工具通過以某種特殊的方式調用本地的C編譯器來發現在Go源文件導入聲明前的註釋中包含的C頭文件中的內容（譯註：<code>import "C"語句前僅捱着的註釋是對應cgo的特殊語法，對應必要的構建參數選項和C語言代碼</code>）。</p>
|
|
<p>在cgo註釋中還可以包含#cgo指令，用於給C語言工具鏈指定特殊的參數。例如CFLAGS和LDFLAGS分别對應傳給C語言編譯器的編譯參數和鏈接器參數，使它們可以特定目録找到bzlib.h頭文件和libbz2.a庫文件。這個例子假設你已經在/usr目録成功安裝了bzip2庫。如果bzip2庫是安裝在不同的位置，你需要更新這些參數。</p>
|
|
<p>NewWriter函數通過調用C語言的BZ2_bzCompressInit函數來初始化stream中的緩存。在writer結構中還包括了另一個buffer，用於輸齣緩存。</p>
|
|
<p>下面是Write方法的實現，返迴成功壓縮數據的大小，主體是一個循環中調用C語言的bz2compress函數實現的。從代碼可以看到，Go程序可以訪問C語言的bz_stream、char和uint類型，還可以訪問bz2compress等函數，甚至可以訪問C語言中像BZ_RUN那樣的宏定義，全部都是以C.x語法訪問。其中C.uint類型和Go語言的uint類型併不相同，卽使它們具有相同的大小也是不同的類型。</p>
|
|
<pre><code class="lang-Go"><span class="hljs-keyword">func</span> (w *writer) Write(data []<span class="hljs-typename">byte</span>) (<span class="hljs-typename">int</span>, error) {
|
|
<span class="hljs-keyword">if</span> w.stream == <span class="hljs-constant">nil</span> {
|
|
<span class="hljs-built_in">panic</span>(<span class="hljs-string">"closed"</span>)
|
|
}
|
|
<span class="hljs-keyword">var</span> total <span class="hljs-typename">int</span> <span class="hljs-comment">// uncompressed bytes written</span>
|
|
|
|
<span class="hljs-keyword">for</span> <span class="hljs-built_in">len</span>(data) > <span class="hljs-number">0</span> {
|
|
inlen, outlen := C.<span class="hljs-typename">uint</span>(<span class="hljs-built_in">len</span>(data)), C.<span class="hljs-typename">uint</span>(<span class="hljs-built_in">cap</span>(w.outbuf))
|
|
C.bz2compress(w.stream, C.BZ_RUN,
|
|
(*C.char)(unsafe.Pointer(&data[<span class="hljs-number">0</span>])), &inlen,
|
|
(*C.char)(unsafe.Pointer(&w.outbuf)), &outlen)
|
|
total += <span class="hljs-typename">int</span>(inlen)
|
|
data = data[inlen:]
|
|
<span class="hljs-keyword">if</span> _, err := w.w.Write(w.outbuf[:outlen]); err != <span class="hljs-constant">nil</span> {
|
|
<span class="hljs-keyword">return</span> total, err
|
|
}
|
|
}
|
|
<span class="hljs-keyword">return</span> total, <span class="hljs-constant">nil</span>
|
|
}
|
|
</code></pre>
|
|
<p>在循環的每次迭代中，向bz2compress傳入數據的地址和剩餘部分的長度，還有輸齣緩存w.outbuf的地址和容量。這兩個長度信息通過它們的地址傳入而不是值傳入，因爲bz2compress函數可能會根據已經壓縮的數據和壓縮後數據的大小來更新這兩個值。每個塊壓縮後的數據被寫入到底層的io.Writer。</p>
|
|
<p>Close方法和Write方法有着類似的結構，通過一個循環將剩餘的壓縮數據刷新到輸齣緩存。</p>
|
|
<pre><code class="lang-Go"><span class="hljs-comment">// Close flushes the compressed data and closes the stream.</span>
|
|
<span class="hljs-comment">// It does not close the underlying io.Writer.</span>
|
|
<span class="hljs-keyword">func</span> (w *writer) Close() error {
|
|
<span class="hljs-keyword">if</span> w.stream == <span class="hljs-constant">nil</span> {
|
|
<span class="hljs-built_in">panic</span>(<span class="hljs-string">"closed"</span>)
|
|
}
|
|
<span class="hljs-keyword">defer</span> <span class="hljs-keyword">func</span>() {
|
|
C.BZ2_bzCompressEnd(w.stream)
|
|
C.bz2free(w.stream)
|
|
w.stream = <span class="hljs-constant">nil</span>
|
|
}()
|
|
<span class="hljs-keyword">for</span> {
|
|
inlen, outlen := C.<span class="hljs-typename">uint</span>(<span class="hljs-number">0</span>), C.<span class="hljs-typename">uint</span>(<span class="hljs-built_in">cap</span>(w.outbuf))
|
|
r := C.bz2compress(w.stream, C.BZ_FINISH, <span class="hljs-constant">nil</span>, &inlen,
|
|
(*C.char)(unsafe.Pointer(&w.outbuf)), &outlen)
|
|
<span class="hljs-keyword">if</span> _, err := w.w.Write(w.outbuf[:outlen]); err != <span class="hljs-constant">nil</span> {
|
|
<span class="hljs-keyword">return</span> err
|
|
}
|
|
<span class="hljs-keyword">if</span> r == C.BZ_STREAM_END {
|
|
<span class="hljs-keyword">return</span> <span class="hljs-constant">nil</span>
|
|
}
|
|
}
|
|
}
|
|
</code></pre>
|
|
<p>壓縮完成後，Close方法用了defer函數確保函數退齣前調用C.BZ2_bzCompressEnd和C.bz2free釋放相關的C语言运行时資源。此刻w.stream指針將不再有效，我們將它設置爲nil以保證安全，然後在每個方法中增加了nil檢測，以防止用戶在關閉後依然錯誤使用相關方法。</p>
|
|
<p>上面的實現中，不僅僅寫是非併發安全的，甚至併發調用Close和Write方法也可能導致程序的的崩潰。脩複這個問題是練習13.3的內容。</p>
|
|
<p>下面的bzipper程序，使用我們自己包實現的bzip2壓縮命令。它的行爲和許多Unix繫統的bzip2命令類似。</p>
|
|
<pre><code class="lang-Go">gopl.io/ch13/bzipper
|
|
|
|
<span class="hljs-comment">// Bzipper reads input, bzip2-compresses it, and writes it out.</span>
|
|
<span class="hljs-keyword">package</span> main
|
|
|
|
<span class="hljs-keyword">import</span> (
|
|
<span class="hljs-string">"io"</span>
|
|
<span class="hljs-string">"log"</span>
|
|
<span class="hljs-string">"os"</span>
|
|
<span class="hljs-string">"gopl.io/ch13/bzip"</span>
|
|
)
|
|
|
|
<span class="hljs-keyword">func</span> main() {
|
|
w := bzip.NewWriter(os.Stdout)
|
|
<span class="hljs-keyword">if</span> _, err := io.Copy(w, os.Stdin); err != <span class="hljs-constant">nil</span> {
|
|
log.Fatalf(<span class="hljs-string">"bzipper: %v\n"</span>, err)
|
|
}
|
|
<span class="hljs-keyword">if</span> err := w.Close(); err != <span class="hljs-constant">nil</span> {
|
|
log.Fatalf(<span class="hljs-string">"bzipper: close: %v\n"</span>, err)
|
|
}
|
|
}
|
|
</code></pre>
|
|
<p>在上面的場景中，我們使用bzipper壓縮了/usr/share/dict/words繫統自帶的詞典，從938,848字節壓縮到335,405字節。大約是原始數據大小的三分之一。然後使用繫統自帶的bunzip2命令進行解壓。壓縮前後文件的SHA256哈希碼是相同了，這也説明了我們的壓縮工具是正確的。（如果你的繫統沒有sha256sum命令，那麽請先按照練習4.2實現一個類似的工具）</p>
|
|
<pre><code>$ go build gopl.io/ch13/bzipper
|
|
$ wc -c < /usr/share/dict/words
|
|
938848
|
|
$ sha256sum < /usr/share/dict/words
|
|
126a4ef38493313edc50b86f90dfdaf7c59ec6c948451eac228f2f3a8ab1a6ed -
|
|
$ ./bzipper < /usr/share/dict/words | wc -c
|
|
335405
|
|
$ ./bzipper < /usr/share/dict/words | bunzip2 | sha256sum
|
|
126a4ef38493313edc50b86f90dfdaf7c59ec6c948451eac228f2f3a8ab1a6ed -
|
|
</code></pre><p>我們演示了如何將一個C語言庫鏈接到Go語言程序。相反, 將Go編譯爲靜態庫然後鏈接到C程序，或者將Go程序編譯爲動態庫然後在C程序中動態加載也都是可行的（譯註：在Go1.5中，Windows繫統的Go語言實現併不支持生成C語言動態庫或靜態庫的特性。不過好消息是，目前已經有人在嚐試解決這個問題，具體請訪問 <a href="https://github.com/golang/go/issues/11058" target="_blank">Issue11058</a> ）。這里我們隻展示的cgo很小的一些方面，更多的關於內存管理、指針、迴調函數、中斷信號處理、字符串、errno處理、終結器，以及goroutines和繫統線程的關繫等，有很多細節可以討論。特别是如何將Go語言的指針傳入C函數的規則也是異常複雜的（譯註：簡單來説，要傳入C函數的Go指針指向的數據本身不能包含指針或其他引用類型；併且C函數在返迴後不能繼續持有Go指針；併且在C函數返迴之前，Go指針是被鎖定的，不能導致對應指針數據被移動或棧的調整），部分的原因在13.2節有討論到，但是在Go1.5中還沒有被明確（譯註：Go1.6將會明確cgo中的指針使用規則）。如果要進一步閲讀，可以從 <a href="https://golang.org/cmd/cgo" target="_blank">https://golang.org/cmd/cgo</a> 開始。</p>
|
|
<p><strong>練習 13.3：</strong> 使用sync.Mutex以保證bzip2.writer在多個goroutines中被併發調用是安全的。</p>
|
|
<p><strong>練習 13.4：</strong> 因爲C庫依賴的限製。 使用os/exec包啟動/bin/bzip2命令作爲一個子進程，提供一個純Go的bzip.NewWriter的替代實現（譯註：雖然是純Go實現，但是運行時將依賴/bin/bzip2命令，其他操作繫統可能無法運行）。</p>
|
|
|
|
|
|
</section>
|
|
|
|
|
|
</div>
|
|
</div>
|
|
</div>
|
|
|
|
|
|
<a href="../ch13/ch13-03.html" class="navigation navigation-prev " aria-label="Previous page: 示例: 深度相等判斷"><i class="fa fa-angle-left"></i></a>
|
|
|
|
|
|
<a href="../ch13/ch13-05.html" class="navigation navigation-next " aria-label="Next page: 幾點忠告"><i class="fa fa-angle-right"></i></a>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
|
|
<script src="../gitbook/app.js"></script>
|
|
|
|
|
|
<script src="../gitbook/plugins/gitbook-plugin-sharing/buttons.js"></script>
|
|
|
|
|
|
|
|
<script src="../gitbook/plugins/gitbook-plugin-fontsettings/buttons.js"></script>
|
|
|
|
|
|
<script>
|
|
require(["gitbook"], function(gitbook) {
|
|
var config = {"highlight":{},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"fontsettings":{"theme":"white","family":"sans","size":2}};
|
|
gitbook.start(config);
|
|
});
|
|
</script>
|
|
|
|
|
|
</body>
|
|
|
|
</html>
|