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<title>Issue 991: Provide allocator for wstring_convert</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++11">C++11</a> status.</em></p>
<h3 id="991"><a href="lwg-defects.html#991">991</a>. Provide allocator for <code>wstring_convert</code></h3>
<p><b>Section:</b> 99 [depr.conversions.string] <b>Status:</b> <a href="lwg-active.html#C++11">C++11</a>
 <b>Submitter:</b> P.J. Plauger <b>Opened:</b> 2009-03-03 <b>Last modified:</b> 2017-04-22</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View other</b> <a href="lwg-index-open.html#depr.conversions.string">active issues</a> in [depr.conversions.string].</p>
<p><b>View all other</b> <a href="lwg-index.html#depr.conversions.string">issues</a> in [depr.conversions.string].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++11">C++11</a> status.</p>
<p><b>Discussion:</b></p>
<p><b>Addresses JP-50 [CD1]</b></p>
<p>
Add custom allocator parameter to <code>wstring_convert</code>, since we cannot
allocate memory for strings from a custom allocator.
</p>

<p><i>[
Batavia (2009-05):
]</i></p>

<blockquote><p>
We agree with the proposed resolution.
Move to Tentatively Ready.
</p></blockquote>


<p id="res-991"><b>Proposed resolution:</b></p>
<p>
Change  [conversions.string]:
</p>

<blockquote><pre>
template&lt;class Codecvt, class Elem = wchar_t<ins>,
         class Wide_alloc = std::allocator&lt;Elem&gt;,
         class Byte_alloc = std::allocator&lt;char&gt; </ins>&gt; class wstring_convert {
  public:
    typedef std::basic_string&lt;char<ins>, char_traits&lt;char&gt;, Byte_alloc</ins>&gt; byte_string;
    typedef std::basic_string&lt;Elem<ins>, char_traits&lt;Elem&gt;, Wide_alloc</ins>&gt; wide_string;
     ...
</pre></blockquote>

<p>
Change  [conversions.string], p3:
</p>

<blockquote><p>
-3- The class template describes an ob ject that controls conversions
between wide string ob jects of class
<code>std::basic_string&lt;Elem<ins>, char_traits&lt;Elem&gt;, Wide_alloc</ins>&gt;</code>
and byte string objects of class
<code>std::basic_string&lt;char<ins>, char_traits&lt;char&gt;, Byte_alloc</ins>&gt;</code>
<del>(also known as <code>std::string</code>)</del>.
</p></blockquote>






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