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<title>Issue 2536: What should &lt;complex.h&gt; do?</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++17">C++17</a> status.</em></p>
<h3 id="2536"><a href="lwg-defects.html#2536">2536</a>. What should <code>&lt;complex.h&gt;</code> do?</h3>
<p><b>Section:</b> 17.15 <a href="https://wg21.link/support.c.headers">[support.c.headers]</a> <b>Status:</b> <a href="lwg-active.html#C++17">C++17</a>
 <b>Submitter:</b> Richard Smith <b>Opened:</b> 2015-09-10 <b>Last modified:</b> 2023-02-07</p>
<p><b>Priority: </b>2
</p>
<p><b>View all other</b> <a href="lwg-index.html#support.c.headers">issues</a> in [support.c.headers].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++17">C++17</a> status.</p>
<p><b>Discussion:</b></p>
<p>
LWG issue <a href="lwg-defects.html#1134" title="Redundant specification of &lt;stdint.h&gt;, &lt;fenv.h&gt;, &lt;tgmath.h&gt;, 
       and maybe &lt;complex.h&gt; (Status: C++11)">1134</a><sup><a href="https://cplusplus.github.io/LWG/issue1134" title="Latest snapshot">(i)</a></sup> removed the resolution of LWG <a href="lwg-defects.html#551" title="&lt;ccomplex&gt; (Status: CD1)">551</a><sup><a href="https://cplusplus.github.io/LWG/issue551" title="Latest snapshot">(i)</a></sup>, leaving an incorrect specification for 
the behavior of <code>&lt;complex.h&gt;</code>. This header is currently required to make <code>std::complex</code> (and 
associated functions) visible in the global namespace, but should not be so required.
</p>

<p><i>[2016-09-09 Issues Resolution Telecon]</i></p>

<p>Move to Tentatively Ready</p>


<p id="res-2536"><b>Proposed resolution:</b></p>
<p>
This wording is relative to N4527.
</p>

<ol>
<li><p>Add a new paragraph <em>before</em>  [depr.c.headers]/2:</p>
<blockquote><p>
<ins>-?- The header <code>&lt;complex.h&gt;</code> behaves as if it simply includes the header <code>&lt;ccomplex&gt;</code>.</ins>
</p></blockquote>
</li>

<li><p>Change in  [depr.c.headers]/2:</p>
<blockquote><p>
-2- Every <ins>other</ins> C header, each of which has a name of the form <code>name.h</code>, behaves as if each name placed 
in the standard library namespace by the corresponding <code>cname</code> header is placed within the global namespace scope. 
It is unspecified whether these names are first declared or defined within namespace scope (3.3.6) of the namespace
<code>std</code> and are then injected into the global namespace scope by explicit <i>using-declarations</i> (7.3.3).
</p></blockquote>
</li>
</ol>





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