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<title>Issue 2956: filesystem::canonical() still defined in terms of absolute(p, base)</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="2956"><a href="lwg-defects.html#2956">2956</a>. <code>filesystem::canonical()</code> still defined in terms of <code>absolute(p, base)</code></h3>
<p><b>Section:</b> 31.12.13.3 <a href="https://wg21.link/fs.op.canonical">[fs.op.canonical]</a> <b>Status:</b> <a href="lwg-active.html#C++17">C++17</a>
 <b>Submitter:</b> Sergey Zubkov <b>Opened:</b> 2017-04-21 <b>Last modified:</b> 2020-09-06</p>
<p><b>Priority: </b>1
</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>
This is from editorial issue <a href="http://github.com/cplusplus/draft/issues/1620">#1620</a>:
<p/>
Since the resolution of US-78 was applied (as part of <a href="https://wg21.link/p0492r2">P0492R2</a>),
<code>std::filesystem::absolute(path, base)</code> no longer exists. However, <code>std::filesystem::canonical</code> 
is still defined in terms of <code>absolute(p, base)</code>.
</p>

<p><i>[2017-06-27 P1 after 5 positive votes on c++std-lib]</i></p>

<p>
Davis Herring: This needs to be P1 &mdash; due to a wording gap in <a href="https://wg21.link/p0492r2">P0492R2</a>, 2 out of the 
3 overloads of <code>filesystem::canonical()</code> have bad signatures and are unimplementable.
</p>

<p><i>[2017-07-14, Toronto, Davis Herring provides wording]</i></p>

<p><i>[2017-07-14, Toronto, Moved to Immediate]</i></p>



<p id="res-2956"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/n4659">N4659</a>.
</p>

<ol>
<li><p>Edit 31.12.4 <a href="https://wg21.link/fs.filesystem.syn">[fs.filesystem.syn]</a> as indicated:</p>

<blockquote>
<pre>
path canonical(const path&amp; p<del>, const path&amp; base = current_path()</del>);
path canonical(const path&amp; p, error_code&amp; ec);
<del>path canonical(const path&amp; p, const path&amp; base, error_code&amp; ec);</del>
</pre>
</blockquote>
</li>

<li><p>Edit 31.12.13.3 <a href="https://wg21.link/fs.op.canonical">[fs.op.canonical]</a> as indicated:</p>

<blockquote>
<pre>
path canonical(const path&amp; p<del>, const path&amp; base = current_path()</del>);
path canonical(const path&amp; p, error_code&amp; ec);
<del>path canonical(const path&amp; p, const path&amp; base, error_code&amp; ec);</del>
</pre>
<blockquote>
<p>
-1- <i>Effects:</i> Converts <code>p</code>, which must exist, to an absolute path that has no symbolic link, <i>dot</i>, or 
<i>dot-dot</i> elements in its pathname in the generic format.
<p/>
-2- <i>Returns:</i> A path that refers to the same file system object as <code>absolute(p<del>, base</del>)</code>. <del>For 
the overload without a <code>base</code> argument, <code>base</code> is <code>current_path()</code>. Signatures</del><ins>The signature</ins> 
with argument <code>ec</code> return<ins>s</ins> <code>path()</code> if an error occurs.
<p/>
[&hellip;]
</p>
</blockquote>
</blockquote>
</li>

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