119 lines
11 KiB
HTML
119 lines
11 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
|
|
<head><meta http-equiv="x-ua-compatible" content="ie=edge">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<title>C++ 属性： deprecated (C++14 起)</title>
|
|
<link rel="stylesheet" href="ext.css" />
|
|
<link rel="stylesheet" href="site_modules.css" />
|
|
</head>
|
|
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_language_attributes_deprecated skin-cppreference2 action-view cpp-navbar">
|
|
<div id="cpp-content-base">
|
|
<div id="content"><a id="top"></a>
|
|
<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">C++ 属性：</span> deprecated <span class="t-mark-rev t-since-cxx14">(C++14 起)</span></h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-language.html">language</a>‎ | <a href="cpp-language-attributes.html">attributes</a></span></div>
|
|
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
|
|
<p>指示声明有此属性的名字或实体被<a href="https://en.wikipedia.org/wiki/Deprecation" class="extiw" title="enwiki:Deprecation">弃用</a>，即允许但因故不鼓励使用。</p>
|
|
<h3><span class="mw-headline" id=".E8.AF.AD.E6.B3.95">语法</span></h3>
|
|
<table class="t-sdsc-begin">
|
|
<tr>
|
|
<td colspan="10" class="t-sdsc-sep"></td>
|
|
</tr>
|
|
<tr class="t-sdsc">
|
|
<td><code><b>[[deprecated</b></code><code><b>]]</b></code></td>
|
|
<td>(1)</td>
|
|
<td class="t-sdsc-nopad"></td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="10" class="t-sdsc-sep"></td>
|
|
</tr>
|
|
<tr class="t-sdsc">
|
|
<td><code><b>[[deprecated(</b></code> <span class="t-spar">字符串字面量</span> <code><b>)]]</b></code></td>
|
|
<td>(2)</td>
|
|
<td class="t-sdsc-nopad"></td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="10" class="t-sdsc-sep"></td>
|
|
</tr>
|
|
</table>
|
|
<table class="t-par-begin">
|
|
<tr class="t-par">
|
|
<td><span class="t-spar">字符串字面量</span></td>
|
|
<td>-</td>
|
|
<td>能用于解释弃用的理由并/或提议代替用实体的文本</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.A7.A3.E9.87.8A">解释</span></h3>
|
|
<p>指示允许使用声明有此属性的名称或实体，但因故不鼓励使用。编译器通常会对其使用情况发出警告。若指定了 <span class="t-spar">字符串字面量</span>，则它通常被包含于警告中。</p>
|
|
<p>下列名字或实体的声明中允许使用这个属性：</p>
|
|
<ul>
|
|
<li><a href="cpp-language-classes.html">class/struct/union</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">struct</span> <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> S<span class="sy4">;</span></span></span>，</li>
|
|
<li><a href="cpp-language-typedef.html">typedef 名</a>，也包括<a href="cpp-language-type_alias.html">别名声明</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> <span class="kw1">typedef</span> S<span class="sy2">*</span> PS<span class="sy4">;</span></span></span>、<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">using</span> PS <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> <span class="sy1">=</span> S<span class="sy2">*</span><span class="sy4">;</span></span></span>，</li>
|
|
<li>变量，包括<a href="cpp-language-static.html">静态数据成员</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> <span class="kw4">int</span> x<span class="sy4">;</span></span></span>，</li>
|
|
<li><a href="cpp-language-data_members.html">非静态数据成员</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">union</span> U <span class="br0">{</span> <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> <span class="kw4">int</span> n<span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span></span></span>，</li>
|
|
<li><a href="cpp-language-function.html">函数</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> <span class="kw4">void</span> f<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span></span></span>，</li>
|
|
<li><a href="cpp-language-namespace.html">命名空间</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">namespace</span> <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> NS <span class="br0">{</span> <span class="kw4">int</span> x<span class="sy4">;</span> <span class="br0">}</span></span></span>，</li>
|
|
<li><a href="cpp-language-enum.html">枚举</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">enum</span> <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> E <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></span></span>，</li>
|
|
<li>枚举项：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">enum</span> <span class="br0">{</span> A <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span>, B <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> <span class="sy1">=</span> <span class="nu0">42</span> <span class="br0">}</span><span class="sy4">;</span></span></span>，</li>
|
|
<li><a href="cpp-language-template_specialization.html">模板特化</a>：<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><></span> <span class="kw1">struct</span> <span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span> X<span class="sy1"><</span><span class="kw4">int</span><span class="sy1">></span> <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></span></span>。</li>
|
|
</ul>
|
|
<p>声明时未弃用的名字可被重声明为 <code>deprecated</code>。声明为 <code>deprecated</code> 的名字不能通过重声明它而不带此属性变为未弃用。</p>
|
|
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
|
|
<div class="t-example">
|
|
<div class="t-example-live-link"></div>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="cpp source-cpp">
|
|
<pre class="de1"><span class="co2">#include <iostream></span>
|
|
|
|
<span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">]</span><span class="br0">]</span>
|
|
<span class="kw4">void</span> TriassicPeriod<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
|
|
<a href="cpp-io-clog.html"><span class="kw1762">std::<span class="me2">clog</span></span></a> <span class="sy1"><<</span> <span class="st0">"Triassic Period: [251.9 - 208.5] million years ago.<span class="es1">\n</span>"</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
|
|
<span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">(</span><span class="st0">"Use NeogenePeriod() instead."</span><span class="br0">)</span><span class="br0">]</span><span class="br0">]</span>
|
|
<span class="kw4">void</span> JurassicPeriod<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
|
|
<a href="cpp-io-clog.html"><span class="kw1762">std::<span class="me2">clog</span></span></a> <span class="sy1"><<</span> <span class="st0">"Jurassic Period: [201.3 - 152.1] million years ago.<span class="es1">\n</span>"</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
|
|
<span class="br0">[</span><span class="br0">[</span>deprecated<span class="br0">(</span><span class="st0">"Use calcSomethingDifferently(int)."</span><span class="br0">)</span><span class="br0">]</span><span class="br0">]</span>
|
|
<span class="kw4">int</span> calcSomething<span class="br0">(</span><span class="kw4">int</span> x<span class="br0">)</span> <span class="br0">{</span>
|
|
<span class="kw1">return</span> x <span class="sy2">*</span> <span class="nu0">2</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
|
|
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
TriassicPeriod<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
|
|
JurassicPeriod<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>可能的输出：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">Triassic Period: [251.9 - 208.5] million years ago.
|
|
Jurassic Period: [201.3 - 152.1] million years ago.
|
|
|
|
main.cpp:20:5: warning: 'TriassicPeriod' is deprecated [-Wdeprecated-declarations]
|
|
TriassicPeriod();
|
|
^
|
|
main.cpp:3:3: note: 'TriassicPeriod' has been explicitly marked deprecated here
|
|
[[deprecated]]
|
|
^
|
|
main.cpp:21:5: warning: 'JurassicPeriod' is deprecated: Use NeogenePeriod() instead [-Wdeprecated-declarations]
|
|
JurassicPeriod();
|
|
^
|
|
main.cpp:8:3: note: 'JurassicPeriod' has been explicitly marked deprecated here
|
|
[[deprecated("Use NeogenePeriod() instead")]]
|
|
^
|
|
2 warnings generated.</pre></div>
|
|
</div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin"></table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|