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<title>Issue 2004: duration::operator* has template parameters in funny order</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#C++11">C++11</a> status.</em></p>
<h3 id="2004"><a href="lwg-defects.html#2004">2004</a>. <code>duration::operator*</code> has template parameters in funny order</h3>
<p><b>Section:</b> 30.5.6 <a href="https://wg21.link/time.duration.nonmember">[time.duration.nonmember]</a> <b>Status:</b> <a href="lwg-active.html#C++11">C++11</a>
 <b>Submitter:</b> P.J. Plauger <b>Opened:</b> 2010-10-14 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#time.duration.nonmember">issues</a> in [time.duration.nonmember].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++11">C++11</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In [time] and [time.duration.nonmember] we have:
</p>
<blockquote><pre>
template &lt;class Rep1, class Period, class Rep2>
    duration&lt;typename common_type&lt;Rep1, Rep2>::type, Period>
        operator*(const Rep1&amp; s, const duration&lt;Rep2, Period>&amp; d);
</pre></blockquote>
<p>
Everywhere else, we always have <code>&lt;rep, period></code> in that order for a given
type. But here, we have <code>Period</code> and <code>Rep2</code> in reverse order for
<code>&lt;Rep2, Period></code>. This is probably of little importance, since the
template parameters are seldom spelled out for a function like this. But changing it
now will eliminate a potential source of future errors and confusion.
</p>


<p id="res-2004"><b>Proposed resolution:</b></p>
<p>
Change the signature in [time] and [time.duration.nonmember] to:
</p>
<blockquote><pre>
template &lt;class Rep1, class <del>Period</del><ins>Rep2</ins>, class <del>Rep2</del><ins>Period</ins>>
    duration&lt;typename common_type&lt;Rep1, Rep2>::type, Period>
        operator*(const Rep1&amp; s, const duration&lt;Rep2, Period>&amp; d);
</pre></blockquote>





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