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<title>Issue 2721: remove_all has incorrect post conditions</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="2721"><a href="lwg-defects.html#2721">2721</a>. <code>remove_all</code> has incorrect post conditions</h3>
<p><b>Section:</b> 31.12.13.32 <a href="https://wg21.link/fs.op.remove.all">[fs.op.remove.all]</a> <b>Status:</b> <a href="lwg-active.html#C++17">C++17</a>
 <b>Submitter:</b> Eric Fiselier <b>Opened:</b> 2016-05-28 <b>Last modified:</b> 2021-06-06</p>
<p><b>Priority: </b>3
</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>
The current post condition for <code>remove_all(p, [...])</code> states:
</p>
<blockquote>
<p>
<i>Postcondition:</i> <code>!exists(p)</code>
</p>
</blockquote>
<p>
This is not correct when <code>p</code> is a symlink, since <code>!exists(p)</code> reads through the symlink.
The postcondition should be changed to match that of <code>remove</code> which states <code>!exists(symlink_status(p))</code>.
</p>

<p><i>[2016-06, Oulu &mdash; Eric clarifies the importance of the suggested change]</i></p>

<p>
With the current post conditions <code>remove_all(p)</code> could just not remove
dangling symlinks and still meet the post conditions.
</p>
<p>Moved to Ready after Eric convinced the room.</p>
<p>Friday: status to Immediate</p>


<p id="res-2721"><b>Proposed resolution:</b></p>
<p>This wording is relative to N4582.</p>
<ol>
<li><p>Change  [fs.op.remove_all] as indicated:</p>

<blockquote>
<pre>
uintmax_t remove_all(const path&amp; p);
uintmax_t remove_all(const path&amp; p, error_code&amp; ec) noexcept;
</pre>
<blockquote>
<p>
-1- <i>Effects:</i> Recursively deletes the contents of <code>p</code> if it exists, then deletes file <code>p</code> itself,
as if by POSIX <code>remove()</code>.
<p/>
-2- [<i>Note:</i> A symbolic link is itself removed, rather than the file it resolves to being removed. &mdash; <i>end note</i>]
<p/>
-3- <i>Postcondition:</i> <code>!exists(<ins>symlink_status(</ins>p<ins>)</ins>)</code>.
</p>
</blockquote>
</blockquote>
</li>
</ol>





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