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<title>Issue 2847: sin(float) should call sinf(float)</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#New">New</a> status.</em></p>
<h3 id="2847"><a href="lwg-active.html#2847">2847</a>. <code>sin(float)</code> should call <code>sinf(float)</code></h3>
<p><b>Section:</b> 29.7.1 <a href="https://wg21.link/cmath.syn">[cmath.syn]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a>
 <b>Submitter:</b> Jens Maurer <b>Opened:</b> 2016-12-15 <b>Last modified:</b> 2020-09-06</p>
<p><b>Priority: </b>3
</p>
<p><b>View other</b> <a href="lwg-index-open.html#cmath.syn">active issues</a> in [cmath.syn].</p>
<p><b>View all other</b> <a href="lwg-index.html#cmath.syn">issues</a> in [cmath.syn].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
With <a href="https://wg21.link/p0175r1">P0175R1</a>, we now show in [cmath.syn] three overloads for
the <code>sin</code> function: One taking a <code>float</code>, one taking a <code>double</code>,
and one taking a <code>long double</code>. However, there is no statement that <code>sin(long double)</code> 
should actually invoke <code>sinl</code>, presumably delivering extra precision.
<p/>
An implementation like
</p>
<blockquote><pre>
inline long double sin(long double x)
{ return sinf(x); }
</pre></blockquote>
<p>
seems to satisfy the "effectively cast" requirement, but is certainly unintentional.
<p/>
The same issue arises for all math functions inherited from C.
<p/>
(Source: <a href="https://github.com/cplusplus/draft/issues/1247">Editorial issue #1247</a>)
</p>

<p><i>[2017-01-27 Telecon]</i></p>

<p>Priority 3</p>


<p id="res-2847"><b>Proposed resolution:</b></p>





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