101 lines
5.9 KiB
HTML
101 lines
5.9 KiB
HTML
<!DOCTYPE html>
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<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
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<head><meta http-equiv="x-ua-compatible" content="ie=edge">
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<title>std::ios_base::Init</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_io_ios_base_Init skin-cppreference2 action-view cpp-navbar">
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<div id="cpp-content-base">
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ios_base::</span>Init</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-io.html">io</a>‎ | <a href="cpp-io-ios_base.html">ios base</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">class</span> Init<span class="sy4">;</span></span></div>
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<p>此类用以确保默认 C++ 流（ <span class="t-lc"><a href="cpp-io-cin.html">std::cin</a></span> 、 <span class="t-lc"><a href="cpp-io-cout.html">std::cout</a></span> 等）被正确初始化及析构。此类跟踪它被创建的实例数量，在构造首个实例时创建并初始化 C++ 流，并且在析构最后实例时冲入输出流。</p>
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<p>头文件 <code><iostream></code> 表现如同它定义（直接或间接）一个有静态存储期的 <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">Init</span></span></span> 实例：这使得在拥有<a href="cpp-language-initialization.html#.E9.9D.9E.E5.B1.80.E9.83.A8.E5.8F.98.E9.87.8F">有序初始化</a>的静态对象的构造函数及析构函数中，访问标准 I/O 流是安全的（只要在翻译单元中，定义该对象前包含 <code>#include <iostream></code> ）。</p>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">成员函数</span></h3>
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<div class="t-dsc-member-div t-dsc-member-nobold-div">
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<div><span class="t-lines"><span>(构造函数)</span></span></div>
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</td>
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<td>若 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> 是首次创建的实例，则初始化默认 C++ 流<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div class="t-dsc-member-div t-dsc-member-nobold-div">
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<div><span class="t-lines"><span>(析构函数)</span></span></div>
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</td>
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<td>若 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> 是被最后销毁的实例，则冲入默认 C++ 流<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
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<div><a href="cpp-io-cin.html"><span class="t-lines"><span>cin</span><span>wcin</span></span></a></div>
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</td>
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<td>从标准 C 输入流 <span class="t-lc"><a href="cpp-io-c.html">stdin</a></span> 中读取<br />
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<span class="t-mark">(全局对象)</span></td>
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<div><a href="cpp-io-cout.html"><span class="t-lines"><span>cout</span><span>wcout</span></span></a></div>
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<td>写入到标准 C 输出流 <span class="t-lc"><a href="cpp-io-c.html">stdout</a></span><br />
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<span class="t-mark">(全局对象)</span></td>
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<div><a href="cpp-io-cerr.html"><span class="t-lines"><span>cerr</span><span>wcerr</span></span></a></div>
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</td>
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<td>写入到标准 C 错误流 <span class="t-lc"><a href="cpp-io-c.html">stderr</a></span>， 无缓冲<br />
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<span class="t-mark">(全局对象)</span></td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-io-clog.html"><span class="t-lines"><span>clog</span><span>wclog</span></span></a></div>
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</div>
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</td>
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<td>写入到标准 C 错误流 <span class="t-lc"><a href="cpp-io-c.html">stderr</a></span><br />
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<span class="t-mark">(全局对象)</span></td>
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