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<title>Issue 57: Mistake in char_traits</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#TC1">TC1</a> status.</em></p>
<h3 id="57"><a href="lwg-defects.html#57">57</a>. Mistake in char_traits</h3>
<p><b>Section:</b> 27.2.4.6 <a href="https://wg21.link/char.traits.specializations.wchar.t">[char.traits.specializations.wchar.t]</a> <b>Status:</b> <a href="lwg-active.html#TC1">TC1</a>
 <b>Submitter:</b> Matt Austern <b>Opened:</b> 1998-07-01 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#TC1">TC1</a> status.</p>
<p><b>Discussion:</b></p>
<p>21.1.3.2, paragraph 3, says &quot;The types streampos and
wstreampos may be different if the implementation supports no shift
encoding in narrow-oriented iostreams but supports one or more shift
encodings in wide-oriented streams&quot;. </p>

<p>That's wrong: the two are the same type. The &lt;iosfwd&gt; summary
in 27.2 says that streampos and wstreampos are, respectively, synonyms
for fpos&lt;char_traits&lt;char&gt;::state_type&gt; and
fpos&lt;char_traits&lt;wchar_t&gt;::state_type&gt;, and, flipping back
to clause 21, we see in 21.1.3.1 and 21.1.3.2 that
char_traits&lt;char&gt;::state_type and
char_traits&lt;wchar_t&gt;::state_type must both be mbstate_t. </p>


<p id="res-57"><b>Proposed resolution:</b></p>
<p>Remove the sentence in 27.2.4.6 <a href="https://wg21.link/char.traits.specializations.wchar.t">[char.traits.specializations.wchar.t]</a> paragraph 3 which
begins &quot;The types streampos and wstreampos may be
different...&quot; . </p>





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