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<title>std::wstring_convert&lt;Codecvt,Elem,Wide_alloc,Byte_alloc&gt;::converted</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::wstring_convert&lt;Codecvt,Elem,Wide_alloc,Byte_alloc&gt;::</span>converted</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-locale.html">locale</a>&lrm; | <a href="cpp-locale-wstring_convert.html">wstring convert</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-locale.html">&lt;locale&gt;</a></code></div>
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<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>
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<p>&#36820;&#22238;&#26368;&#36817;&#30340; <span class="t-lc"><a href="cpp-locale-wstring_convert-from_bytes.html">from_bytes()</a></span> &#25110; <span class="t-lc"><a href="cpp-locale-wstring_convert-to_bytes.html">to_bytes()</a></span> &#25152;&#22788;&#29702;&#30340;&#28304;&#23383;&#31526;&#25968;&#12290;</p>
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#26368;&#36817;&#30340;&#36716;&#25442;&#25805;&#20316;&#25152;&#28040;&#32791;&#30340;&#23383;&#31526;&#25968;&#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;string&gt;</span>
<span class="co2">#include &lt;locale&gt;</span>
<span class="co2">#include &lt;codecvt&gt;</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">&quot;z<span class="es3">\u00df</span><span class="es3">\u6c34</span><span class="es4">\U0001d10b</span>&quot;</span><span class="sy4">;</span> <span class="co1">// &#25110; u8&quot;z&szlig;&#27700;&#119051;&quot;</span>
<span class="co1">// &#25110; &quot;\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b&quot;;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;original UTF-8 string size: &quot;</span> <span class="sy1">&lt;&lt;</span> utf8.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="co1">// UTF-8 - UTF-32 &#26631;&#20934;&#36716;&#25442;&#24179;&#38754;</span>
<a href="cpp-locale-wstring_convert.html"><span class="kw1899">std::<span class="me2">wstring_convert</span></span></a><span class="sy1">&lt;</span><a href="cpp-locale-codecvt_utf8.html"><span class="kw1983">std::<span class="me2">codecvt_utf8</span></span></a><span class="sy1">&lt;</span><span class="kw4">char32_t</span><span class="sy1">&gt;</span>, <span class="kw4">char32_t</span><span class="sy1">&gt;</span> cvt<span class="sy4">;</span>
<span class="co1">// UTF-8 &#21040; 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">&lt;&lt;</span> <span class="st0">&quot;UTF-32 string size: &quot;</span> <span class="sy1">&lt;&lt;</span> utf32.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</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">&lt;&lt;</span> <span class="st0">&quot;converted() == &quot;</span> <span class="sy1">&lt;&lt;</span> cvt.<span class="me1">converted</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="co1">// UTF-32 &#21040; 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">&lt;&lt;</span> <span class="st0">&quot;new UTF-8 string size: &quot;</span> <span class="sy1">&lt;&lt;</span> utf8.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</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">&lt;&lt;</span> <span class="st0">&quot;converted() == &quot;</span> <span class="sy1">&lt;&lt;</span> cvt.<span class="me1">converted</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
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<p>&#36755;&#20986;&#65306;</p>
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<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>
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<h3><span class="mw-headline" id=".E7.BC.BA.E9.99.B7.E6.8A.A5.E5.91.8A">&#32570;&#38519;&#25253;&#21578;</span></h3>
<p>&#19979;&#21015;&#26356;&#25913;&#34892;&#20026;&#30340;&#32570;&#38519;&#25253;&#21578;&#36861;&#28335;&#22320;&#24212;&#29992;&#20110;&#20197;&#21069;&#20986;&#29256;&#30340; C++ &#26631;&#20934;&#12290;</p>
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<th>DR</th>
<th>&#24212;&#29992;&#20110;</th>
<th>&#20986;&#29256;&#26102;&#30340;&#34892;&#20026;</th>
<th>&#27491;&#30830;&#34892;&#20026;</th>
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<td><a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue2174">LWG 2174</a></td>
<td>C++11</td>
<td>&#26410;&#35201;&#27714; <code>wstring_convert::converted</code> &#20026; noexcept</td>
<td>&#24050;&#35201;&#27714;</td>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="cpp-locale-wstring_convert-to_bytes.html"><span class="t-lines"><span>to_bytes</span></span></a></div>
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<td>&#36716;&#25442;&#23485;&#23383;&#31526;&#20018;&#20026;&#23383;&#31526;&#20018;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<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>
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<td>&#36716;&#25442;&#23383;&#33410;&#23383;&#31526;&#20018;&#20026;&#23485;&#23383;&#31526;&#20018;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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