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<title>Issue 2178: Allocator requirement changes not mentioned Annex C</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">Pending NAD Editorial</a> status.</em></p>
<h3 id="2178"><a href="lwg-closed.html#2178">2178</a>. <code>Allocator</code> requirement changes not mentioned Annex C</h3>
<p><b>Section:</b> 16.4.4.6 <a href="https://wg21.link/allocator.requirements">[allocator.requirements]</a>, C.8 <a href="https://wg21.link/diff.library">[diff.library]</a> <b>Status:</b> <a href="lwg-active.html#NAD_Editorial">Pending NAD Editorial</a>
 <b>Submitter:</b> Nevin Liber <b>Opened:</b> 2012-08-14 <b>Last modified:</b> 2016-11-21</p>
<p><b>Priority: </b>3
</p>
<p><b>View other</b> <a href="lwg-index-open.html#allocator.requirements">active issues</a> in [allocator.requirements].</p>
<p><b>View all other</b> <a href="lwg-index.html#allocator.requirements">issues</a> in [allocator.requirements].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#Pending NAD Editorial">Pending NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>

<p>
Given that a number of things were removed from the allocator requirements (<code>reference</code>, <code>const_reference</code>, 
<code>address()</code> in 16.4.4.6 <a href="https://wg21.link/allocator.requirements">[allocator.requirements]</a>), it seems that these incompatible changes should be 
mentioned in Annex C.8 <a href="https://wg21.link/diff.library">[diff.library]</a>, more specifically in [diff.cpp03].
</p>

<p><i>[
2012-10 Portland: Move to Open 
]</i></p>


<p>
It was clearly pointed out by Bill during the C++11 process that our change to allocator requirements
potentially broke 3rd party user containers written to expect C++03 allocators, or rather, an
allocator written to the minimal requirements of C++11 might not be guaranteed to work with a container
written to the previous rules.  This was a trade-off in making allocaters easier to write by use of
the <code>allocator_traits</code> framework.
</p>

<p>
This probably does merit a write-up in Annex C, and we look forward to seeing wording.  Until then,
the best we can do is move the issue to Open.
</p>

<p><i>[2016-11-12, Issaquah]</i></p>

<p>Sat PM: JW to provide Annex C wording Status to "Pending NAD Editorial".</p>


<p id="res-2178"><b>Proposed resolution:</b></p>





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