72 lines
6.8 KiB
HTML
72 lines
6.8 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::experimental::ranges::View</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_experimental_ranges_range_View 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::experimental::ranges::</span>View</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-experimental.html">experimental</a>‎ | <a href="cpp-experimental-ranges.html">ranges</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-experimental-ranges-range.html"><experimental/ranges/range></a></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-ranges">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1"><</span><span class="kw1">class</span> T<span class="sy1">></span><br /></span>
|
|
<p>concept <span class="kw4">bool</span> View <span class="sy1">=</span> <a href="cpp-experimental-ranges-range-Range.html"><span class="kw2588">ranges::<span class="me2">Range</span></span></a><span class="sy1"><</span>T<span class="sy1">></span> <span class="sy3">&&</span> <a href="cpp-experimental-ranges-concepts-Semiregular.html"><span class="kw2554">ranges::<span class="me2">Semiregular</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><br /></p>
|
|
<span class="sy3">&&</span> <span class="coMULTI">/* view-predicate<T> */</span><span class="sy4">;</span></div>
|
|
</td>
|
|
<td class="t-dcl-nopad"></td>
|
|
<td><span class="t-mark-rev t-since-ranges-ts t-mark-ts">(范围 TS)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-ranges">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T<span class="sy1">></span><br />
|
|
<span class="kw1">struct</span> enable_view <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td class="t-dcl-nopad"></td>
|
|
<td><span class="t-mark-rev t-since-ranges-ts t-mark-ts">(范围 TS)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-ranges">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">struct</span> view_base <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td class="t-dcl-nopad"></td>
|
|
<td><span class="t-mark-rev t-since-ranges-ts t-mark-ts">(范围 TS)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>概念 <code>View<T></code> 指定半常规范围 <code>T</code> 拥有常数时间的复制、移动和赋值操作。</p>
|
|
<p>概念的 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="coMULTI">/* view-predicate<T> */</span></span></span> 部分定义如下：</p>
|
|
<ul>
|
|
<li>若 <i>qualified-id</i> <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">enable_view</span><span class="sy1"><</span>T<span class="sy1">></span><span class="sy4">::</span><span class="me2">type</span></span></span> 合法并代表一个范围，则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">enable_view</span><span class="sy1"><</span>T<span class="sy1">></span><span class="sy4">::</span><span class="me2">type</span><span class="sy4">::</span><span class="me2">value</span></span></span> ；</li>
|
|
<li>否则，若 <span class="t-c"><span class="mw-geshi cpp source-cpp"><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>ranges<span class="sy4">::</span><span class="me2">view_base</span>, T<span class="sy1">></span></span></span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> ，则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> ；</li>
|
|
<li>否则，若 <code>T</code> 是 <span class="t-lc"><a href="cpp-utility-initializer_list.html">std::initializer_list</a></span> 、 <span class="t-lc"><a href="cpp-container-set.html">std::set</a></span> 、 <span class="t-lc"><a href="cpp-container-multiset.html">std::multiset</a></span> 、 <span class="t-lc"><a href="cpp-container-unordered_set.html">std::unordered_set</a></span> 或 <span class="t-lc"><a href="cpp-container-unordered_multiset.html">std::unordered_multiset</a></span> 的特化，则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span> ；</li>
|
|
<li>否则，若 <code>T</code> 与 <code>const T</code> 均满足<a href="cpp-experimental-ranges-range-Range.html"><code>Range</code></a>且 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">reference_t</span> <span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>T<span class="sy1">>></span></span></span> 与 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">reference_t</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span><span class="kw4">const</span> T<span class="sy1">>></span></span></span> 不是同一类型，则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span> ；</li>
|
|
<li>否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> 。</li>
|
|
</ul>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|