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<title>Issue 3033: basic_string move ctor is underspecified</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_Editorial">NAD Editorial</a> status.</em></p>
<h3 id="3033"><a href="lwg-closed.html#3033">3033</a>. <code>basic_string</code> move ctor is underspecified</h3>
<p><b>Section:</b> 27.4.3.3 <a href="https://wg21.link/string.cons">[string.cons]</a> <b>Status:</b> <a href="lwg-active.html#NAD_Editorial">NAD Editorial</a>
 <b>Submitter:</b> Peter Sommerlad <b>Opened:</b> 2017-11-09 <b>Last modified:</b> 2017-11-29</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#string.cons">issues</a> in [string.cons].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#NAD Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The standard has a hole in the specification of <code>basic_string</code>'s move constructor that seems not only be editorial.
In 27.4.3.3 <a href="https://wg21.link/string.cons">[string.cons]</a> p2:
</p>
<blockquote><pre>
basic_string(const basic_string&amp; str);
basic_string(basic_string&amp;&amp; str) noexcept;
</pre><blockquote>
<p>
<i>Effects:</i> Constructs an object of class <code>basic_string</code> as indicated in Table 56. In the second form, 
<code>str</code> is left in a valid state with an unspecified value.
</p>
</blockquote>
</blockquote>
<p>
refers to Table 56, but that table only speaks about copy-ctor. According to Pablo, move and copy differ in what they do.
Move ctor of <code>basic_string</code> needs separate table (entry) to describe what happens.
</p>
<p><i>[28-Nov-2017 After discussion on the ML, closing as NAD Editorial]</i></p>



<p id="res-3033"><b>Proposed resolution:</b></p>





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