124 lines
8.6 KiB
HTML
124 lines
8.6 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>std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::converted</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_locale_wstring_convert_converted 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%">std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::</span>converted</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-locale.html">locale</a>‎ | <a href="cpp-locale-wstring_convert.html">wstring convert</a></span></div>
|
|
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
|
|
<table class="t-dcl-begin">
|
|
<tbody>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><a href="cpp-header-locale.html"><locale></a></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl">
|
|
<td class="t-dcl-nopad">
|
|
<div><span class="mw-geshi cpp source-cpp"><a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> converted<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td class="t-dcl-nopad"></td>
|
|
<td class="t-dcl-nopad"></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>返回最近的 <span class="t-lc"><a href="cpp-locale-wstring_convert-from_bytes.html">from_bytes()</a></span> 或 <span class="t-lc"><a href="cpp-locale-wstring_convert-to_bytes.html">to_bytes()</a></span> 所处理的源字符数。</p>
|
|
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
|
|
<p>最近的转换操作所消耗的字符数。</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="co2">#include <string></span>
|
|
<span class="co2">#include <locale></span>
|
|
<span class="co2">#include <codecvt></span>
|
|
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> utf8 <span class="sy1">=</span> u8<span class="st0">"z<span class="es3">\u00df</span><span class="es3">\u6c34</span><span class="es4">\U0001d10b</span>"</span><span class="sy4">;</span> <span class="co1">// 或 u8"zß水𝄋"</span>
|
|
<span class="co1">// 或 "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b";</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"original UTF-8 string size: "</span> <span class="sy1"><<</span> utf8.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
|
|
<span class="co1">// UTF-8 - UTF-32 标准转换平面</span>
|
|
<a href="cpp-locale-wstring_convert.html"><span class="kw1899">std::<span class="me2">wstring_convert</span></span></a><span class="sy1"><</span><a href="cpp-locale-codecvt_utf8.html"><span class="kw1983">std::<span class="me2">codecvt_utf8</span></span></a><span class="sy1"><</span><span class="kw4">char32_t</span><span class="sy1">></span>, <span class="kw4">char32_t</span><span class="sy1">></span> cvt<span class="sy4">;</span>
|
|
|
|
<span class="co1">// UTF-8 到 UTF-32</span>
|
|
<a href="cpp-string-basic_string.html"><span class="kw1236">std::<span class="me2">u32string</span></span></a> utf32 <span class="sy1">=</span> cvt.<span class="me1">from_bytes</span><span class="br0">(</span>utf8<span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"UTF-32 string size: "</span> <span class="sy1"><<</span> utf32.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"converted() == "</span> <span class="sy1"><<</span> cvt.<span class="me1">converted</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
<span class="co1">// UTF-32 到 UTF-8</span>
|
|
utf8 <span class="sy1">=</span> cvt.<span class="me1">to_bytes</span><span class="br0">(</span>utf32<span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"new UTF-8 string size: "</span> <span class="sy1"><<</span> utf8.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"converted() == "</span> <span class="sy1"><<</span> cvt.<span class="me1">converted</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>输出:</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">original UTF-8 string size: 10
|
|
UTF-32 string size: 4
|
|
converted() == 10
|
|
new UTF-8 string size: 10
|
|
converted() == 4</pre></div>
|
|
</div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E7.BC.BA.E9.99.B7.E6.8A.A5.E5.91.8A">缺陷报告</span></h3>
|
|
<p>下列更改行为的缺陷报告追溯地应用于以前出版的 C++ 标准。</p>
|
|
<table class="dsctable" style="font-size:0.8em">
|
|
<tr>
|
|
<th>DR</th>
|
|
<th>应用于</th>
|
|
<th>出版时的行为</th>
|
|
<th>正确行为</th>
|
|
</tr>
|
|
<tr>
|
|
<td><a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue2174">LWG 2174</a></td>
|
|
<td>C++11</td>
|
|
<td>未要求 <code>wstring_convert::converted</code> 为 noexcept</td>
|
|
<td>已要求</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-locale-wstring_convert-to_bytes.html"><span class="t-lines"><span>to_bytes</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>转换宽字符串为字符串<br />
|
|
<span class="t-mark">(公开成员函数)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-locale-wstring_convert-from_bytes.html"><span class="t-lines"><span>from_bytes</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>转换字节字符串为宽字符串<br />
|
|
<span class="t-mark">(公开成员函数)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|