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<title>Issue 2761: directory_entry comparisons are members</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#NAD">NAD</a> status.</em></p>
<h3 id="2761"><a href="lwg-closed.html#2761">2761</a>. <code>directory_entry</code> comparisons are members</h3>
<p><b>Section:</b> 31.12.10.4 <a href="https://wg21.link/fs.dir.entry.obs">[fs.dir.entry.obs]</a> <b>Status:</b> <a href="lwg-active.html#NAD">NAD</a>
 <b>Submitter:</b> Ville Voutilainen <b>Opened:</b> 2016-08-03 <b>Last modified:</b> 2017-03-19</p>
<p><b>Priority: </b>2
</p>
<p><b>View all other</b> <a href="lwg-index.html#fs.dir.entry.obs">issues</a> in [fs.dir.entry.obs].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The comparison operators for <code>directory_entry</code> are member functions
(31.12.10.4 <a href="https://wg21.link/fs.dir.entry.obs">[fs.dir.entry.obs]</a>).
<p/>
That means that a <code>directory_entry</code> can be compared with a <code>path</code>,
but a <code>path</code> cannot be compared with a <code>directory_entry</code>, because
the left-hand side is not subject to conversions. This seems
unfortunate.
<p/>
Note that the comparisons for <code>path</code> are non-members (31.12.6.8 <a href="https://wg21.link/fs.path.nonmember">[fs.path.nonmember]</a>).
<p/>
The meta-p/r is to turn the <code>directory_entry</code> comparisons into non-member functions.
</p>

<p><i>[2016-08 Chicago]</i></p>

<p>Wed PM: Priority 2</p>

<p><i>[2016-10-05 Ville provides concrete wording]</i></p>


<p><i>[2016-10 Telecon]</i></p>

<p>This (comparing a <code>path</code> with a <code>directory_entry</code>) works today w/o any changes. Closing as NAD.</p>


<p id="res-2761"><b>Proposed resolution:</b></p>
<p>This wording is relative to N4606.</p>

<ol>
<li><p>In  [fs.class.directory_entry] synopsis, edit as follows:</p>

<blockquote>
<pre>
namespace std::filesystem {
class directory_entry {
public:
  [&hellip;]
  <del>bool operator&lt; (const directory_entry&amp; rhs) const noexcept;
  bool operator==(const directory_entry&amp; rhs) const noexcept;
  bool operator!=(const directory_entry&amp; rhs) const noexcept;
  bool operator&lt;=(const directory_entry&amp; rhs) const noexcept;
  bool operator&gt; (const directory_entry&amp; rhs) const noexcept;
  bool operator&gt;=(const directory_entry&amp; rhs) const noexcept;</del>

private:
  path pathobject; // exposition only
};
<ins>
bool operator&lt; (const directory_entry&amp; lhs, const directory_entry&amp; rhs) noexcept;
bool operator==(const directory_entry&amp; lhs, const directory_entry&amp; rhs) noexcept;
bool operator!=(const directory_entry&amp; lhs, const directory_entry&amp; rhs) noexcept;
bool operator&lt;=(const directory_entry&amp; lhs, const directory_entry&amp; rhs) noexcept;
bool operator&gt; (const directory_entry&amp; lhs, const directory_entry&amp; rhs) noexcept;
bool operator&gt;=(const directory_entry&amp; lhs, const directory_entry&amp; rhs) noexcept;
</ins>
}
</pre>
</blockquote>
</li>

<li><p>In 31.12.10.4 <a href="https://wg21.link/fs.dir.entry.obs">[fs.dir.entry.obs]</a>/6-11, edit as follows:</p>

<blockquote>
<pre>
bool operator==(<ins>const directory_entry&amp; lhs,</ins> const directory_entry&amp; rhs) <del>const</del> noexcept;
</pre>
<blockquote>
<p>
-6- <i>Returns:</i> <code><del>pathobject</del><ins>lhs.path()</ins> == rhs.<del>pathobject</del><ins>path()</ins></code>.
</p>
</blockquote>
<pre>
bool operator!=(<ins>const directory_entry&amp; lhs,</ins> const directory_entry&amp; rhs) <del>const</del> noexcept;
</pre>
<blockquote>
<p>
-7- <i>Returns:</i>: <code><del>pathobject</del><ins>lhs.path()</ins> != rhs.<del>pathobject</del><ins>path()</ins></code>.
</p>
</blockquote>
<pre>
bool operator&lt; (<ins>const directory_entry&amp; lhs,</ins> const directory_entry&amp; rhs) <del>const</del> noexcept;
</pre>
<blockquote>
<p>
-8- <i>Returns:</i>: <code><del>pathobject</del><ins>lhs.path()</ins> &lt; rhs.<del>pathobject</del><ins>path()</ins></code>.
</p>
</blockquote>
<pre>
bool operator&lt;&lt;=(<ins>const directory_entry&amp; lhs,</ins> const directory_entry&amp; rhs) <del>const</del> noexcept;
</pre>
<blockquote>
<p>
-9- <i>Returns:</i>: <code><del>pathobject</del><ins>lhs.path()</ins> &lt;= rhs.<del>pathobject</del><ins>path()</ins></code>.
</p>
</blockquote>
<pre>
bool operator&gt; (<ins>const directory_entry&amp; lhs,</ins> const directory_entry&amp; rhs) <del>const</del> noexcept;
</pre>
<blockquote>
<p>
-10- <i>Returns:</i>: <code><del>pathobject</del><ins>lhs.path()</ins> > rhs.<del>pathobject</del><ins>path()</ins></code>.
</p>
</blockquote>
<pre>
bool operator&gt;=(<ins>const directory_entry&amp; lhs,</ins> const directory_entry&amp; rhs) <del>const</del> noexcept;
</pre>
<blockquote>
<p>
-11- <i>Returns:</i>: <code><del>pathobject</del><ins>lhs.path()</ins> &gt;= rhs.<del>pathobject</del><ins>path()</ins></code>.
</p>
</blockquote>
</blockquote>
</li>
</ol>





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