mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-11-14 10:23:42 +00:00
293 lines
31 KiB
HTML
293 lines
31 KiB
HTML
<!DOCTYPE HTML>
|
||
<html lang="zh" class="sidebar-visible no-js light">
|
||
<head>
|
||
<!-- Book generated using mdBook -->
|
||
<meta charset="UTF-8">
|
||
<title>error接口 - Go语言圣经</title>
|
||
|
||
|
||
<!-- Custom HTML head -->
|
||
|
||
|
||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||
<meta name="description" content="<The Go Programming Language>中文版">
|
||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||
<meta name="theme-color" content="#ffffff" />
|
||
|
||
<link rel="icon" href="../favicon.svg">
|
||
<link rel="shortcut icon" href="../favicon.png">
|
||
<link rel="stylesheet" href="../css/variables.css">
|
||
<link rel="stylesheet" href="../css/general.css">
|
||
<link rel="stylesheet" href="../css/chrome.css">
|
||
<link rel="stylesheet" href="../css/print.css" media="print">
|
||
|
||
<!-- Fonts -->
|
||
<link rel="stylesheet" href="../FontAwesome/css/font-awesome.css">
|
||
<link rel="stylesheet" href="../fonts/fonts.css">
|
||
|
||
<!-- Highlight.js Stylesheets -->
|
||
<link rel="stylesheet" href="../highlight.css">
|
||
<link rel="stylesheet" href="../tomorrow-night.css">
|
||
<link rel="stylesheet" href="../ayu-highlight.css">
|
||
|
||
<!-- Custom theme stylesheets -->
|
||
<link rel="stylesheet" href="../style.css">
|
||
|
||
|
||
</head>
|
||
<body>
|
||
<!-- Provide site root to javascript -->
|
||
<script type="text/javascript">
|
||
var path_to_root = "../";
|
||
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
|
||
</script>
|
||
|
||
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
||
<script type="text/javascript">
|
||
try {
|
||
var theme = localStorage.getItem('mdbook-theme');
|
||
var sidebar = localStorage.getItem('mdbook-sidebar');
|
||
|
||
if (theme.startsWith('"') && theme.endsWith('"')) {
|
||
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
||
}
|
||
|
||
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
||
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
||
}
|
||
} catch (e) { }
|
||
</script>
|
||
|
||
<!-- Set the theme before any content is loaded, prevents flash -->
|
||
<script type="text/javascript">
|
||
var theme;
|
||
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
||
if (theme === null || theme === undefined) { theme = default_theme; }
|
||
var html = document.querySelector('html');
|
||
html.classList.remove('no-js')
|
||
html.classList.remove('light')
|
||
html.classList.add(theme);
|
||
html.classList.add('js');
|
||
</script>
|
||
|
||
<!-- Hide / unhide sidebar before it is displayed -->
|
||
<script type="text/javascript">
|
||
var html = document.querySelector('html');
|
||
var sidebar = 'hidden';
|
||
if (document.body.clientWidth >= 1080) {
|
||
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
||
sidebar = sidebar || 'visible';
|
||
}
|
||
html.classList.remove('sidebar-visible');
|
||
html.classList.add("sidebar-" + sidebar);
|
||
</script>
|
||
|
||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||
<div class="sidebar-scrollbox">
|
||
<ol class="chapter"><li class="chapter-item expanded affix "><a href="../index.html">Go语言圣经</a></li><li class="chapter-item expanded affix "><a href="../preface.html">前言</a></li><li class="chapter-item expanded "><a href="../ch1/ch1.html"><strong aria-hidden="true">1.</strong> 入门</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch1/ch1-01.html"><strong aria-hidden="true">1.1.</strong> Hello, World</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-02.html"><strong aria-hidden="true">1.2.</strong> 命令行参数</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-03.html"><strong aria-hidden="true">1.3.</strong> 查找重复的行</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-04.html"><strong aria-hidden="true">1.4.</strong> GIF动画</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-05.html"><strong aria-hidden="true">1.5.</strong> 获取URL</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-06.html"><strong aria-hidden="true">1.6.</strong> 并发获取多个URL</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-07.html"><strong aria-hidden="true">1.7.</strong> Web服务</a></li><li class="chapter-item expanded "><a href="../ch1/ch1-08.html"><strong aria-hidden="true">1.8.</strong> 本章要点</a></li></ol></li><li class="chapter-item expanded "><a href="../ch2/ch2.html"><strong aria-hidden="true">2.</strong> 程序结构</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch2/ch2-01.html"><strong aria-hidden="true">2.1.</strong> 命名</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-02.html"><strong aria-hidden="true">2.2.</strong> 声明</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-03.html"><strong aria-hidden="true">2.3.</strong> 变量</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-04.html"><strong aria-hidden="true">2.4.</strong> 赋值</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-05.html"><strong aria-hidden="true">2.5.</strong> 类型</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-06.html"><strong aria-hidden="true">2.6.</strong> 包和文件</a></li><li class="chapter-item expanded "><a href="../ch2/ch2-07.html"><strong aria-hidden="true">2.7.</strong> 作用域</a></li></ol></li><li class="chapter-item expanded "><a href="../ch3/ch3.html"><strong aria-hidden="true">3.</strong> 基础数据类型</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch3/ch3-01.html"><strong aria-hidden="true">3.1.</strong> 整型</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-02.html"><strong aria-hidden="true">3.2.</strong> 浮点数</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-03.html"><strong aria-hidden="true">3.3.</strong> 复数</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-04.html"><strong aria-hidden="true">3.4.</strong> 布尔型</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-05.html"><strong aria-hidden="true">3.5.</strong> 字符串</a></li><li class="chapter-item expanded "><a href="../ch3/ch3-06.html"><strong aria-hidden="true">3.6.</strong> 常量</a></li></ol></li><li class="chapter-item expanded "><a href="../ch4/ch4.html"><strong aria-hidden="true">4.</strong> 复合数据类型</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch4/ch4-01.html"><strong aria-hidden="true">4.1.</strong> 数组</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-02.html"><strong aria-hidden="true">4.2.</strong> Slice</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-03.html"><strong aria-hidden="true">4.3.</strong> Map</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-04.html"><strong aria-hidden="true">4.4.</strong> 结构体</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-05.html"><strong aria-hidden="true">4.5.</strong> JSON</a></li><li class="chapter-item expanded "><a href="../ch4/ch4-06.html"><strong aria-hidden="true">4.6.</strong> 文本和HTML模板</a></li></ol></li><li class="chapter-item expanded "><a href="../ch5/ch5.html"><strong aria-hidden="true">5.</strong> 函数</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch5/ch5-01.html"><strong aria-hidden="true">5.1.</strong> 函数声明</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-02.html"><strong aria-hidden="true">5.2.</strong> 递归</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-03.html"><strong aria-hidden="true">5.3.</strong> 多返回值</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-04.html"><strong aria-hidden="true">5.4.</strong> 错误</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-05.html"><strong aria-hidden="true">5.5.</strong> 函数值</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-06.html"><strong aria-hidden="true">5.6.</strong> 匿名函数</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-07.html"><strong aria-hidden="true">5.7.</strong> 可变参数</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-08.html"><strong aria-hidden="true">5.8.</strong> Deferred函数</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-09.html"><strong aria-hidden="true">5.9.</strong> Panic异常</a></li><li class="chapter-item expanded "><a href="../ch5/ch5-10.html"><strong aria-hidden="true">5.10.</strong> Recover捕获异常</a></li></ol></li><li class="chapter-item expanded "><a href="../ch6/ch6.html"><strong aria-hidden="true">6.</strong> 方法</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch6/ch6-01.html"><strong aria-hidden="true">6.1.</strong> 方法声明</a></li><li class="chapter-item expanded "><a href="../ch6/ch6-02.html"><strong aria-hidden="true">6.2.</strong> 基于指针对象的方法</a></li><li class="chapter-item expanded "><a href="../ch6/ch6-03.html"><strong aria-hidden="true">6.3.</strong> 通过嵌入结构体来扩展类型</a></li><li class="chapter-item expanded "><a href="../ch6/ch6-04.html"><strong aria-hidden="true">6.4.</strong> 方法值和方法表达式</a></li><li class="chapter-item expanded "><a href="../ch6/ch6-05.html"><strong aria-hidden="true">6.5.</strong> 示例: Bit数组</a></li><li class="chapter-item expanded "><a href="../ch6/ch6-06.html"><strong aria-hidden="true">6.6.</strong> 封装</a></li></ol></li><li class="chapter-item expanded "><a href="../ch7/ch7.html"><strong aria-hidden="true">7.</strong> 接口</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch7/ch7-01.html"><strong aria-hidden="true">7.1.</strong> 接口是合约</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-02.html"><strong aria-hidden="true">7.2.</strong> 接口类型</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-03.html"><strong aria-hidden="true">7.3.</strong> 实现接口的条件</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-04.html"><strong aria-hidden="true">7.4.</strong> flag.Value接口</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-05.html"><strong aria-hidden="true">7.5.</strong> 接口值</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-06.html"><strong aria-hidden="true">7.6.</strong> sort.Interface接口</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-07.html"><strong aria-hidden="true">7.7.</strong> http.Handler接口</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-08.html" class="active"><strong aria-hidden="true">7.8.</strong> error接口</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-09.html"><strong aria-hidden="true">7.9.</strong> 示例: 表达式求值</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-10.html"><strong aria-hidden="true">7.10.</strong> 类型断言</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-11.html"><strong aria-hidden="true">7.11.</strong> 基于类型断言识别错误类型</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-12.html"><strong aria-hidden="true">7.12.</strong> 通过类型断言查询接口</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-13.html"><strong aria-hidden="true">7.13.</strong> 类型分支</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-14.html"><strong aria-hidden="true">7.14.</strong> 示例: 基于标记的XML解码</a></li><li class="chapter-item expanded "><a href="../ch7/ch7-15.html"><strong aria-hidden="true">7.15.</strong> 补充几点</a></li></ol></li><li class="chapter-item expanded "><a href="../ch8/ch8.html"><strong aria-hidden="true">8.</strong> Goroutines和Channels</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch8/ch8-01.html"><strong aria-hidden="true">8.1.</strong> Goroutines</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-02.html"><strong aria-hidden="true">8.2.</strong> 示例: 并发的Clock服务</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-03.html"><strong aria-hidden="true">8.3.</strong> 示例: 并发的Echo服务</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-04.html"><strong aria-hidden="true">8.4.</strong> Channels</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-05.html"><strong aria-hidden="true">8.5.</strong> 并发的循环</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-06.html"><strong aria-hidden="true">8.6.</strong> 示例: 并发的Web爬虫</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-07.html"><strong aria-hidden="true">8.7.</strong> 基于select的多路复用</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-09.html"><strong aria-hidden="true">8.8.</strong> 并发的退出</a></li><li class="chapter-item expanded "><a href="../ch8/ch8-10.html"><strong aria-hidden="true">8.9.</strong> 示例: 聊天服务</a></li></ol></li><li class="chapter-item expanded "><a href="../ch9/ch9.html"><strong aria-hidden="true">9.</strong> 基于共享变量的并发</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch9/ch9-01.html"><strong aria-hidden="true">9.1.</strong> 竞争条件</a></li><li class="chapter-item expanded "><a href="../ch9/ch9-02.html"><strong aria-hidden="true">9.2.</strong> sync.Mutex互斥锁</a></li><li class="chapter-item expanded "><a href="../ch9/ch9-03.html"><strong aria-hidden="true">9.3.</strong> sync.RWMutex读写锁</a></li><li class="chapter-item expanded "><a href="../ch9/ch9-04.html"><strong aria-hidden="true">9.4.</strong> 内存同步</a></li><li class="chapter-item expanded "><a href="../ch9/ch9-06.html"><strong aria-hidden="true">9.5.</strong> 竞争条件检测</a></li><li class="chapter-item expanded "><a href="../ch9/ch9-07.html"><strong aria-hidden="true">9.6.</strong> 示例: 并发的非阻塞缓存</a></li><li class="chapter-item expanded "><a href="../ch9/ch9-08.html"><strong aria-hidden="true">9.7.</strong> Goroutines和线程</a></li></ol></li><li class="chapter-item expanded "><a href="../ch10/ch10.html"><strong aria-hidden="true">10.</strong> 包和工具</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch10/ch10-01.html"><strong aria-hidden="true">10.1.</strong> 包简介</a></li><li class="chapter-item expanded "><a href="../ch10/ch10-02.html"><strong aria-hidden="true">10.2.</strong> 导入路径</a></li><li class="chapter-item expanded "><a href="../ch10/ch10-03.html"><strong aria-hidden="true">10.3.</strong> 包声明</a></li><li class="chapter-item expanded "><a href="../ch10/ch10-04.html"><strong aria-hidden="true">10.4.</strong> 导入声明</a></li><li class="chapter-item expanded "><a href="../ch10/ch10-05.html"><strong aria-hidden="true">10.5.</strong> 包的匿名导入</a></li><li class="chapter-item expanded "><a href="../ch10/ch10-06.html"><strong aria-hidden="true">10.6.</strong> 包和命名</a></li><li class="chapter-item expanded "><a href="../ch10/ch10-07.html"><strong aria-hidden="true">10.7.</strong> 工具</a></li></ol></li><li class="chapter-item expanded "><a href="../ch11/ch11.html"><strong aria-hidden="true">11.</strong> 测试</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch11/ch11-01.html"><strong aria-hidden="true">11.1.</strong> go test</a></li><li class="chapter-item expanded "><a href="../ch11/ch11-02.html"><strong aria-hidden="true">11.2.</strong> 测试函数</a></li><li class="chapter-item expanded "><a href="../ch11/ch11-03.html"><strong aria-hidden="true">11.3.</strong> 测试覆盖率</a></li><li class="chapter-item expanded "><a href="../ch11/ch11-04.html"><strong aria-hidden="true">11.4.</strong> 基准测试</a></li><li class="chapter-item expanded "><a href="../ch11/ch11-05.html"><strong aria-hidden="true">11.5.</strong> 剖析</a></li><li class="chapter-item expanded "><a href="../ch11/ch11-06.html"><strong aria-hidden="true">11.6.</strong> 示例函数</a></li></ol></li><li class="chapter-item expanded "><a href="../ch12/ch12.html"><strong aria-hidden="true">12.</strong> 反射</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch12/ch12-01.html"><strong aria-hidden="true">12.1.</strong> 为何需要反射?</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-02.html"><strong aria-hidden="true">12.2.</strong> reflect.Type和reflect.Value</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-03.html"><strong aria-hidden="true">12.3.</strong> Display递归打印</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-04.html"><strong aria-hidden="true">12.4.</strong> 示例: 编码S表达式</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-05.html"><strong aria-hidden="true">12.5.</strong> 通过reflect.Value修改值</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-06.html"><strong aria-hidden="true">12.6.</strong> 示例: 解码S表达式</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-08.html"><strong aria-hidden="true">12.7.</strong> 显示一个类型的方法集</a></li><li class="chapter-item expanded "><a href="../ch12/ch12-09.html"><strong aria-hidden="true">12.8.</strong> 几点忠告</a></li></ol></li><li class="chapter-item expanded "><a href="../ch13/ch13.html"><strong aria-hidden="true">13.</strong> 底层编程</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../ch13/ch13-01.html"><strong aria-hidden="true">13.1.</strong> unsafe.Sizeof, Alignof 和 Offsetof</a></li><li class="chapter-item expanded "><a href="../ch13/ch13-02.html"><strong aria-hidden="true">13.2.</strong> unsafe.Pointer</a></li><li class="chapter-item expanded "><a href="../ch13/ch13-03.html"><strong aria-hidden="true">13.3.</strong> 示例: 深度相等判断</a></li><li class="chapter-item expanded "><a href="../ch13/ch13-04.html"><strong aria-hidden="true">13.4.</strong> 通过cgo调用C代码</a></li><li class="chapter-item expanded "><a href="../ch13/ch13-05.html"><strong aria-hidden="true">13.5.</strong> 几点忠告</a></li></ol></li><li class="chapter-item expanded "><a href="../appendix/appendix.html"><strong aria-hidden="true">14.</strong> 附录</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../appendix/appendix-a-errata.html"><strong aria-hidden="true">14.1.</strong> 附录A：原文勘误</a></li><li class="chapter-item expanded "><a href="../appendix/appendix-b-author.html"><strong aria-hidden="true">14.2.</strong> 附录B：作者译者</a></li><li class="chapter-item expanded "><a href="../appendix/appendix-c-cpoyright.html"><strong aria-hidden="true">14.3.</strong> 附录C：译文授权</a></li><li class="chapter-item expanded "><a href="../appendix/appendix-d-translations.html"><strong aria-hidden="true">14.4.</strong> 附录D：其它语言</a></li></ol></li></ol> </div>
|
||
<div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
|
||
</nav>
|
||
|
||
<div id="page-wrapper" class="page-wrapper">
|
||
|
||
<div class="page">
|
||
|
||
<div id="menu-bar-hover-placeholder"></div>
|
||
<div id="menu-bar" class="menu-bar sticky bordered">
|
||
<div class="left-buttons">
|
||
<button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
||
<i class="fa fa-bars"></i>
|
||
</button>
|
||
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
||
<i class="fa fa-paint-brush"></i>
|
||
</button>
|
||
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
||
<li role="none"><button role="menuitem" class="theme" id="light">Light (default)</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
||
</ul>
|
||
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
||
<i class="fa fa-search"></i>
|
||
</button>
|
||
</div>
|
||
|
||
<h1 class="menu-title">Go语言圣经</h1>
|
||
|
||
<div class="right-buttons">
|
||
<a href="../print.html" title="Print this book" aria-label="Print this book">
|
||
<i id="print-button" class="fa fa-print"></i>
|
||
</a>
|
||
<a href="https://github.com/gopl-zh/gopl-zh.github.com" title="Git repository" aria-label="Git repository">
|
||
<i id="git-repository-button" class="fa fa-github"></i>
|
||
</a>
|
||
<a href="https://github.com/gopl-zh/gopl-zh.github.com/edit/master/./ch7/ch7-08.md" title="Suggest an edit" aria-label="Suggest an edit">
|
||
<i id="git-edit-button" class="fa fa-edit"></i>
|
||
</a>
|
||
|
||
</div>
|
||
</div>
|
||
|
||
<div id="search-wrapper" class="hidden">
|
||
<form id="searchbar-outer" class="searchbar-outer">
|
||
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
||
</form>
|
||
<div id="searchresults-outer" class="searchresults-outer hidden">
|
||
<div id="searchresults-header" class="searchresults-header"></div>
|
||
<ul id="searchresults">
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
|
||
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
||
<script type="text/javascript">
|
||
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
||
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
||
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
||
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
||
});
|
||
</script>
|
||
|
||
<div id="content" class="content">
|
||
<!-- Page table of contents -->
|
||
<div class="sidetoc"><nav class="pagetoc"></nav></div>
|
||
<main>
|
||
<!-- 头部 -->
|
||
<ul dir="auto">
|
||
<li><em>KusonStack一站式可编程配置技术栈(Go): <a href="https://github.com/KusionStack/kusion">https://github.com/KusionStack/kusion</a></em></li>
|
||
<li><em>KCL 配置编程语言(Rust): <a href="https://github.com/KusionStack/KCLVM">https://github.com/KusionStack/KCLVM</a></em></li>
|
||
<li><em>凹语言™: <a href="https://github.com/wa-lang/wa">https://github.com/wa-lang/wa</a></em></li>
|
||
</ul>
|
||
<hr>
|
||
|
||
<h2 id="78-error接口"><a class="header" href="#78-error接口">7.8. error接口</a></h2>
|
||
<p>从本书的开始，我们就已经创建和使用过神秘的预定义error类型，而且没有解释它究竟是什么。实际上它就是interface类型，这个类型有一个返回错误信息的单一方法：</p>
|
||
<pre><code class="language-go">type error interface {
|
||
Error() string
|
||
}
|
||
</code></pre>
|
||
<p>创建一个error最简单的方法就是调用errors.New函数，它会根据传入的错误信息返回一个新的error。整个errors包仅只有4行：</p>
|
||
<pre><code class="language-go">package errors
|
||
|
||
func New(text string) error { return &errorString{text} }
|
||
|
||
type errorString struct { text string }
|
||
|
||
func (e *errorString) Error() string { return e.text }
|
||
</code></pre>
|
||
<p>承载errorString的类型是一个结构体而非一个字符串，这是为了保护它表示的错误避免粗心（或有意）的更新。并且因为是指针类型<code>*errorString</code>满足error接口而非errorString类型，所以每个New函数的调用都分配了一个独特的和其他错误不相同的实例。我们也不想要重要的error例如io.EOF和一个刚好有相同错误消息的error比较后相等。</p>
|
||
<pre><code class="language-go">fmt.Println(errors.New("EOF") == errors.New("EOF")) // "false"
|
||
</code></pre>
|
||
<p>调用errors.New函数是非常稀少的，因为有一个方便的封装函数fmt.Errorf，它还会处理字符串格式化。我们曾多次在第5章中用到它。</p>
|
||
<pre><code class="language-go">package fmt
|
||
|
||
import "errors"
|
||
|
||
func Errorf(format string, args ...interface{}) error {
|
||
return errors.New(Sprintf(format, args...))
|
||
}
|
||
</code></pre>
|
||
<p>虽然<code>*errorString</code>可能是最简单的错误类型，但远非只有它一个。例如，syscall包提供了Go语言底层系统调用API。在多个平台上，它定义一个实现error接口的数字类型Errno，并且在Unix平台上，Errno的Error方法会从一个字符串表中查找错误消息，如下面展示的这样：</p>
|
||
<pre><code class="language-go">package syscall
|
||
|
||
type Errno uintptr // operating system error code
|
||
|
||
var errors = [...]string{
|
||
1: "operation not permitted", // EPERM
|
||
2: "no such file or directory", // ENOENT
|
||
3: "no such process", // ESRCH
|
||
// ...
|
||
}
|
||
|
||
func (e Errno) Error() string {
|
||
if 0 <= int(e) && int(e) < len(errors) {
|
||
return errors[e]
|
||
}
|
||
return fmt.Sprintf("errno %d", e)
|
||
}
|
||
</code></pre>
|
||
<p>下面的语句创建了一个持有Errno值为2的接口值，表示POSIX ENOENT状况：</p>
|
||
<pre><code class="language-go">var err error = syscall.Errno(2)
|
||
fmt.Println(err.Error()) // "no such file or directory"
|
||
fmt.Println(err) // "no such file or directory"
|
||
</code></pre>
|
||
<p>err的值图形化的呈现在图7.6中。</p>
|
||
<p><img src="../images/ch7-06.png" alt="" /></p>
|
||
<p>Errno是一个系统调用错误的高效表示方式，它通过一个有限的集合进行描述，并且它满足标准的错误接口。我们会在第7.11节了解到其它满足这个接口的类型。</p>
|
||
|
||
|
||
<!-- 公众号 -->
|
||
<hr>
|
||
<table>
|
||
<tr>
|
||
<td>
|
||
<img width="222px" src="https://chai2010.cn/advanced-go-programming-book/css.png">
|
||
</td>
|
||
<td>
|
||
<img width="222px" src="https://chai2010.cn/advanced-go-programming-book/cch.png">
|
||
</td>
|
||
</tr>
|
||
</table>
|
||
|
||
<div id="giscus-container"></div>
|
||
<footer class="page-footer">
|
||
<span>© 2015-2016 | <a href="https://github.com/gopl-zh"> Go语言圣经中文版</a>, 仅学习交流使用</span>
|
||
</footer>
|
||
</main>
|
||
|
||
<nav class="nav-wrapper" aria-label="Page navigation">
|
||
<!-- Mobile navigation buttons -->
|
||
<a rel="prev" href="../ch7/ch7-07.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
||
<i class="fa fa-angle-left"></i>
|
||
</a>
|
||
|
||
<a rel="next" href="../ch7/ch7-09.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||
<i class="fa fa-angle-right"></i>
|
||
</a>
|
||
|
||
<div style="clear: both"></div>
|
||
</nav>
|
||
</div>
|
||
</div>
|
||
|
||
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
||
<a rel="prev" href="../ch7/ch7-07.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
||
<i class="fa fa-angle-left"></i>
|
||
</a>
|
||
|
||
<a rel="next" href="../ch7/ch7-09.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||
<i class="fa fa-angle-right"></i>
|
||
</a>
|
||
</nav>
|
||
|
||
</div>
|
||
|
||
|
||
|
||
|
||
<script type="text/javascript">
|
||
window.playground_copyable = true;
|
||
</script>
|
||
|
||
|
||
<script src="../elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||
<script src="../mark.min.js" type="text/javascript" charset="utf-8"></script>
|
||
<script src="../searcher.js" type="text/javascript" charset="utf-8"></script>
|
||
|
||
<script src="../clipboard.min.js" type="text/javascript" charset="utf-8"></script>
|
||
<script src="../highlight.js" type="text/javascript" charset="utf-8"></script>
|
||
<script src="../book.js" type="text/javascript" charset="utf-8"></script>
|
||
<script type="text/javascript" charset="utf-8">
|
||
var pagePath = "ch7/ch7-08.md"
|
||
</script>
|
||
|
||
|
||
<!-- Custom JS scripts -->
|
||
<script type="text/javascript" src="../js/custom.js"></script>
|
||
<script type="text/javascript" src="../js/bigPicture.js"></script>
|
||
|
||
|
||
</body>
|
||
</html>
|