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<div class="identifier-type">type-alias</div><div class="header"><chrono></div><h1 itemprop="name"><span class="namespace" title="namespace std::chrono">std::chrono::</span><span class="token">時間間隔を表す型</span><span class="cpp cpp11" title="C++11で追加">(C++11)</span></h1>
<div itemprop="articleBody"><p><div class="codehilite"><pre><span></span><code><span class="k">namespace</span><span class="w"> </span><span class="nn">std</span><span class="w"> </span><span class="p">{</span>
<span class="k">namespace</span><span class="w"> </span><span class="nn">chrono</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">nanoseconds</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても64ビットを持つ符号付き整数型</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../ratio/si_prefix.html">nano</a></span><span class="o">></span><span class="p">;</span><span class="w"> </span><span class="c1">// (1) C++11</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">microseconds</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても55ビットを持つ符号付き整数型</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../ratio/si_prefix.html">micro</a></span><span class="o">></span><span class="p">;</span><span class="w"> </span><span class="c1">// (2) C++11</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">milliseconds</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても45ビットを持つ符号付き整数型</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../ratio/si_prefix.html">milli</a></span><span class="o">></span><span class="p">;</span><span class="w"> </span><span class="c1">// (3) C++11</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">seconds</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても35ビットを持つ符号付き整数型</span><span class="o">></span><span class="p">;</span><span class="w"> </span><span class="c1">// (4) C++11</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">minutes</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても29ビットを持つ符号付き整数型</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../ratio/ratio.html">ratio</a></span><span class="o"><</span><span class="mi">60</span><span class="o">>></span><span class="p">;</span><span class="w"> </span><span class="c1">// (5) C++11</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">hours</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても23ビットを持つ符号付き整数型</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../ratio/ratio.html">ratio</a></span><span class="o"><</span><span class="mi">3600</span><span class="o">>></span><span class="p">;</span><span class="w"> </span><span class="c1">// (6) C++11</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">days</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても25ビットを持つ符号付き整数型</span><span class="p">,</span>
<span class="w"> </span><span class="n"><a href="../ratio/ratio_multiply.html">ratio_multiply</a></span><span class="o"><</span><span class="n"><a href="../ratio/ratio.html">ratio</a></span><span class="o"><</span><span class="mi">24</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n"><a href="">hours</a></span><span class="o">::</span><span class="n">period</span><span class="o">>></span><span class="p">;</span><span class="w"> </span><span class="c1">// (7) C++20</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">weeks</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても22ビットを持つ符号付き整数型</span><span class="p">,</span>
<span class="w"> </span><span class="n"><a href="../ratio/ratio_multiply.html">ratio_multiply</a></span><span class="o"><</span><span class="n"><a href="../ratio/ratio.html">ratio</a></span><span class="o"><</span><span class="mi">7</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n"><a href="">days</a></span><span class="o">::</span><span class="n">period</span><span class="o">>></span><span class="p">;</span><span class="w"> </span><span class="c1">// (8) C++20</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">years</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても17ビットを持つ符号付き整数型</span><span class="p">,</span>
<span class="w"> </span><span class="n"><a href="../ratio/ratio_multiply.html">ratio_multiply</a></span><span class="o"><</span><span class="n"><a href="../ratio/ratio.html">ratio</a></span><span class="o"><</span><span class="mi">146097</span><span class="p">,</span><span class="w"> </span><span class="mi">400</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n"><a href="">days</a></span><span class="o">::</span><span class="n">period</span><span class="o">>></span><span class="p">;</span><span class="w"> </span><span class="c1">// (9) C++20</span>
<span class="w"> </span><span class="k">using</span><span class="w"> </span><span class="n"><a href="">months</a></span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration.html">duration</a></span><span class="o"><</span><span class="n">少なくても20ビットを持つ符号付き整数型</span><span class="p">,</span>
<span class="w"> </span><span class="n"><a href="../ratio/ratio_divide.html">ratio_divide</a></span><span class="o"><</span><span class="n"><a href="">years</a></span><span class="o">::</span><span class="n">period</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../ratio/ratio.html">ratio</a></span><span class="o"><</span><span class="mi">12</span><span class="o">>>></span><span class="p">;</span><span class="w"> </span><span class="c1">// (10) C++20</span>
<span class="p">}}</span>
</code></pre></div>
</p>
<h2>概要</h2>
<p>さまざまな日付・時間単位の時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名。</p>
<ul>
<li>(1) : ナノ秒単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(2) : マイクロ秒単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(3) : ミリ秒単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(4) : 秒単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(5) : 分単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(6) : 時単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(7) : 日単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(8) : 週単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(9) : 年単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
<li>(10) : 月単位で時間間隔を表現する<code><a href="duration.html">duration</a></code>型の別名</li>
</ul>
<h2>備考</h2>
<ul>
<li>単位ごとの値を保持する型として「最低でもNビットを持つ符号付き整数型」という定義がされるが、これは標準ライブラリがサポートするすべての時間単位で±292年を最小範囲として表現できることを意図している<ul>
<li>ナノ秒として64ビット符号付き整数を使用した場合、±292年の範囲を扱える</li>
<li>時としての規定は23ビット以上だが、23ビットの場合に表現できる範囲は±478年となり、1ビットを減らして22ビットにすると表現範囲は±239年となる。22ビットでは目標の±292を下回ってしまう</li>
</ul>
</li>
<li>1ヶ月を表す<code>duration</code>は年を12で割った値となるため、月は年よりあとに定義される</li>
<li>年は、400年に97回だけうるう年があるため、400年分の日数146097を400で割った平均的な年の日数として定義される</li>
</ul>
<h2>例</h2>
<h3>単位変換を含む基本的な使い方 (C++11)</h3>
<p><div class="yata" id="275dc52ec6a4578bdf550aab0eb0dbc3aa5b8978"><div class="codehilite"><pre><span></span><code><span class="cp">#include <a href="../iostream.html"><iostream></a></span>
<span class="cp">#include <a href="../chrono.html"><chrono></a></span>
<span class="k">namespace</span><span class="w"> </span><span class="nn">chrono</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nn">std</span><span class="o">::</span><span class="nn">chrono</span><span class="p">;</span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span>
<span class="p">{</span>
<span class="w"> </span><span class="n"><a href="">chrono::seconds</a></span><span class="w"> </span><span class="n">s1</span><span class="p">{</span><span class="mi">30</span><span class="p">};</span>
<span class="w"> </span><span class="n"><a href="">chrono::seconds</a></span><span class="w"> </span><span class="n">s2</span><span class="p">{</span><span class="mi">20</span><span class="p">};</span>
<span class="w"> </span><span class="c1">// 秒同士の演算</span>
<span class="w"> </span><span class="c1">// 30秒 + 20秒 = 50秒</span>
<span class="w"> </span><span class="n"><a href="">chrono::seconds</a></span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">s1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">s2</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="c1">// 秒からミリ秒に変換</span>
<span class="w"> </span><span class="c1">// 50秒 = 50000ミリ秒</span>
<span class="w"> </span><span class="n"><a href="">chrono::milliseconds</a></span><span class="w"> </span><span class="n">ms</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">result</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">ms</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="c1">// 秒から分に変換</span>
<span class="w"> </span><span class="c1">// 65秒は1分5秒だが、整数表現の分に変換する際に5秒が切り捨てられるため、</span>
<span class="w"> </span><span class="c1">// 1分となる。</span>
<span class="w"> </span><span class="c1">// 切り捨てが発生する場合には、<a href="duration_cast.html">duration_cast</a>()関数を使用する。</span>
<span class="w"> </span><span class="n"><a href="">chrono::seconds</a></span><span class="w"> </span><span class="n">s3</span><span class="p">{</span><span class="mi">65</span><span class="p">};</span>
<span class="w"> </span><span class="n"><a href="">chrono::minutes</a></span><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration_cast.html">chrono::duration_cast</a></span><span class="o"><</span><span class="n"><a href="">chrono::minutes</a></span><span class="o">></span><span class="p">(</span><span class="n">s3</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">m</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="p">}</span>
</code></pre></div>
</div></p>
<h4>出力</h4>
<p><pre><code>50
50000
1
</code></pre></p>
<h3>日付単位の変換 (C++20)</h3>
<p><div class="yata" id="46d3dcabd07bd32f1c4755f6ab8d934a66059120"><div class="codehilite"><pre><span></span><code><span class="cp">#include <a href="../cassert.html"><cassert></a></span>
<span class="cp">#include <a href="../chrono.html"><chrono></a></span>
<span class="k">using</span><span class="w"> </span><span class="k">namespace</span><span class="w"> </span><span class="nn">std</span><span class="o">::</span><span class="nn">chrono</span><span class="p">;</span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span>
<span class="p">{</span>
<span class="w"> </span><span class="c1">// 年から月への変換。<a href="duration_cast.html">duration_cast</a>は不要</span>
<span class="w"> </span><span class="n"><a href="">months</a></span><span class="w"> </span><span class="n">m1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="">years</a></span><span class="p">{</span><span class="mi">3</span><span class="p">};</span>
<span class="w"> </span><span class="n"><a href="../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">m1</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">36</span><span class="p">);</span>
<span class="w"> </span><span class="c1">// 月から年への変換。<a href="duration_cast.html">duration_cast</a>が必要</span>
<span class="w"> </span><span class="n"><a href="">months</a></span><span class="w"> </span><span class="n">m2</span><span class="p">{</span><span class="mi">37</span><span class="p">};</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">y2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration_cast.html">duration_cast</a></span><span class="o"><</span><span class="n"><a href="">years</a></span><span class="o">></span><span class="p">(</span><span class="n">m2</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">y2</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">3</span><span class="p">);</span>
<span class="w"> </span><span class="c1">// 年から日への変換。</span>
<span class="w"> </span><span class="c1">// 400年の平均的な日数として年が定義されるため、日に変換する際に端数が発生する。</span>
<span class="w"> </span><span class="c1">// そのため、<a href="duration_cast.html">duration_cast</a>が必要</span>
<span class="w"> </span><span class="n"><a href="">days</a></span><span class="w"> </span><span class="n">d3</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration_cast.html">duration_cast</a></span><span class="o"><</span><span class="n"><a href="">days</a></span><span class="o">></span><span class="p">(</span><span class="n"><a href="">years</a></span><span class="p">{</span><span class="mi">1</span><span class="p">});</span>
<span class="w"> </span><span class="n"><a href="../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">d3</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">365</span><span class="p">);</span>
<span class="w"> </span><span class="c1">// 日から年への変換。端数が発生するため、<a href="duration_cast.html">duration_cast</a>が必要</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">y4</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration_cast.html">duration_cast</a></span><span class="o"><</span><span class="n"><a href="">years</a></span><span class="o">></span><span class="p">(</span><span class="n"><a href="">days</a></span><span class="p">{</span><span class="mi">366</span><span class="p">});</span>
<span class="w"> </span><span class="n"><a href="../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">y4</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">1</span><span class="p">);</span>
<span class="w"> </span><span class="c1">// 月から週への変換。端数が発生するため、<a href="duration_cast.html">duration_cast</a>が必要</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">w5</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration_cast.html">duration_cast</a></span><span class="o"><</span><span class="n"><a href="">weeks</a></span><span class="o">></span><span class="p">(</span><span class="n"><a href="">months</a></span><span class="p">{</span><span class="mi">1</span><span class="p">});</span>
<span class="w"> </span><span class="n"><a href="../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">w5</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">4</span><span class="p">);</span>
<span class="w"> </span><span class="c1">// 年から週への変換。<a href="duration_cast.html">duration_cast</a>が必要</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">w6</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="duration_cast.html">duration_cast</a></span><span class="o"><</span><span class="n"><a href="">weeks</a></span><span class="o">></span><span class="p">(</span><span class="n"><a href="">years</a></span><span class="p">{</span><span class="mi">1</span><span class="p">});</span>
<span class="w"> </span><span class="n"><a href="../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">w6</span><span class="p">.</span><span class="n"><a href="duration/count.html">count()</a></span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">52</span><span class="p">);</span>
<span class="p">}</span>
</code></pre></div>
</div></p>
<h4>出力</h4>
<p><pre><code></code></pre></p>
<h2>バージョン</h2>
<h3>言語</h3>
<ul>
<li>C++11</li>
</ul>
<h3>処理系</h3>
<ul>
<li><a href="../../implementation.html#clang">Clang</a>: 3.2 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
<li><a href="../../implementation.html#gcc">GCC</a>: 4.6.1 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
<li><a href="../../implementation.html#visual_cpp">Visual C++</a>: 2012 <span aria-label="検証済" role="img" title="検証済">✅</span>, 2013 <span aria-label="検証済" role="img" title="検証済">✅</span>, 2015 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
</ul>
<h2>関連項目</h2>
<ul>
<li><code><a href="../thread/this_thread/sleep_for.html">sleep_for</a></code></li>
<li><code><a href="../thread/this_thread/sleep_until.html">sleep_until</a></code></li>
</ul></div>
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