89 lines
4.7 KiB
HTML
89 lines
4.7 KiB
HTML
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<title>std::basic_string_view<CharT,Traits>::copy</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::basic_string_view<CharT,Traits>::</span>copy</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-string.html">string</a>‎ | <a href="cpp-string-basic_string_view.html">basic string view</a></span></div>
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<div><span class="mw-geshi cpp source-cpp">size_type copy<span class="br0">(</span> CharT<span class="sy2">*</span> dest, size_type count, size_type pos <span class="sy1">=</span> <span class="nu0">0</span> <span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span><br />
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<span class="t-mark-rev t-until-cxx20">(C++20 前)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> size_type copy<span class="br0">(</span> CharT<span class="sy2">*</span> dest, size_type count,<br />
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size_type pos <span class="sy1">=</span> <span class="nu0">0</span> <span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<p>复制子串 <code>[pos, pos + rcount)</code> 到 <code>dest</code> 所指向的字符序列，其中 <code>rcount</code> 是 <code>count</code> 与 <span class="t-c"><span class="mw-geshi cpp source-cpp">size<span class="br0">(</span><span class="br0">)</span> <span class="sy2">-</span> pos</span></span> 中较小者。</p>
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<p>等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp">Traits<span class="sy4">::</span><span class="me2">copy</span><span class="br0">(</span>dest, data<span class="br0">(</span><span class="br0">)</span> <span class="sy2">+</span> pos, rcount<span class="br0">)</span></span></span> 。</p>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
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<td>dest</td>
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<td>-</td>
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<td>指向目标字符串的指针</td>
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</tr>
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<tr class="t-par">
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<td>pos</td>
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<td>-</td>
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<td>首字符的位置</td>
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<tr class="t-par">
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<td>count</td>
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<td>-</td>
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<td>请求的字符串长度</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<p>复制的字符数</p>
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<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">异常</span></h3>
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<p>若 <span class="t-c"><span class="mw-geshi cpp source-cpp">pos <span class="sy1">></span> size<span class="br0">(</span><span class="br0">)</span></span></span> 则抛出 <span class="t-lc"><a href="cpp-error-out_of_range.html">std::out_of_range</a></span> 。</p>
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<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">复杂度</span></h3>
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<p>与 <code>rcount</code> 成线性。</p>
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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 class="t-dsc-member-div">
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<div><a href="cpp-string-basic_string_view-substr.html"><span class="t-lines"><span>substr</span></span></a></div>
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</div>
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</td>
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<td>返回子串<br />
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<span class="t-mark">(公开成员函数)</span></td>
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