TimeTraits.html
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<div class="titlepage"><div><div><h3 class="title">
<a name="asio.reference.TimeTraits"></a><a class="link" href="TimeTraits.html" title="Time traits requirements">Time traits requirements</a>
</h3></div></div></div>
<p>
In the table below, <code class="computeroutput">X</code> denotes a time traits class for time type
<code class="computeroutput">Time</code>, <code class="computeroutput">t</code>, <code class="computeroutput">t1</code>, and <code class="computeroutput">t2</code> denote
values of type <code class="computeroutput">Time</code>, and <code class="computeroutput">d</code> denotes a value of type
<code class="computeroutput">X::duration_type</code>.
</p>
<div class="table">
<a name="asio.reference.TimeTraits.t0"></a><p class="title"><b>Table 32. TimeTraits requirements</b></p>
<div class="table-contents"><table class="table" summary="TimeTraits requirements">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
expression
</p>
</th>
<th>
<p>
return type
</p>
</th>
<th>
<p>
assertion/note<br> pre/post-condition
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
<code class="computeroutput">X::time_type</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">Time</code>
</p>
</td>
<td>
<p>
Represents an absolute time. Must support default construction,
and meet the requirements for <code class="computeroutput">CopyConstructible</code> and
<code class="computeroutput">Assignable</code>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">X::duration_type</code>
</p>
</td>
<td>
</td>
<td>
<p>
Represents the difference between two absolute times. Must support
default construction, and meet the requirements for <code class="computeroutput">CopyConstructible</code>
and <code class="computeroutput">Assignable</code>. A duration can be positive, negative,
or zero.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">X::now();</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">time_type</code>
</p>
</td>
<td>
<p>
Returns the current time.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">X::add(t, d);</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">time_type</code>
</p>
</td>
<td>
<p>
Returns a new absolute time resulting from adding the duration
<code class="computeroutput">d</code> to the absolute time <code class="computeroutput">t</code>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">X::subtract(t1, t2);</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">duration_type</code>
</p>
</td>
<td>
<p>
Returns the duration resulting from subtracting <code class="computeroutput">t2</code>
from <code class="computeroutput">t1</code>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">X::less_than(t1, t2);</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">bool</code>
</p>
</td>
<td>
<p>
Returns whether <code class="computeroutput">t1</code> is to be treated as less than
<code class="computeroutput">t2</code>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">X::to_posix_duration(d);</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">date_time::time_duration_type</code>
</p>
</td>
<td>
<p>
Returns the <code class="computeroutput">date_time::time_duration_type</code> value that
most closely represents the duration <code class="computeroutput">d</code>.
</p>
</td>
</tr>
</tbody>
</table></div>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M.
Kohlhoff<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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