74 lines
4.3 KiB
HTML
74 lines
4.3 KiB
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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<title>std::derived_from</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_concepts_derived_from 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::</span>derived_from</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-concepts.html">concepts</a></span></div>
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<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
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<div>定义于头文件 <code><a href="cpp-header-concepts.html"><concepts></a></code></div>
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<td></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> Derived, <span class="kw1">class</span> Base <span class="sy1">></span><br /></span>
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<p>concept derived_from <span class="sy1">=</span><br />
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<a href="cpp-types-is_base_of.html"><span class="kw591">std::<span class="me2">is_base_of_v</span></span></a><span class="sy1"><</span>Base, Derived<span class="sy1">></span> <span class="sy3">&&</span><br /></p>
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<a href="cpp-types-is_convertible.html"><span class="kw593">std::<span class="me2">is_convertible_v</span></span></a><span class="sy1"><</span><span class="kw4">const</span> <span class="kw4">volatile</span> Derived<span class="sy2">*</span>, <span class="kw4">const</span> <span class="kw4">volatile</span> Base<span class="sy2">*</span><span class="sy1">></span><span class="sy4">;</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>概念 <span class="t-c"><span class="mw-geshi cpp source-cpp">derived_from<span class="sy1"><</span>Derived, Base<span class="sy1">></span></span></span> 若且唯若忽略 cv 限定符后 <code>Base</code> 是类类型，且它为 <code>Derived</code> 或是 <code>Derived</code> 的公开无歧义基类才得到满足。</p>
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<p>注意当 <code>Base</code> 是 <code>Derived</code> 的私有或受保护基类时，此行为异于 <code>std::is_base_of</code> 。</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><a href="cpp-types-is_base_of.html"><span class="t-lines"><span>is_base_of</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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</div>
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</td>
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<td>检查一个类型是否派生自另一个类型<br />
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<span class="t-mark">(类模板)</span></td>
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<tr class="t-dsc">
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<div><a href="cpp-types-is_convertible.html"><span class="t-lines"><span>is_convertible</span><span>is_nothrow_convertible</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</td>
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<td>检查是否能转换一个类型为另一类型<br />
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<span class="t-mark">(类模板)</span></td>
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