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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_Concepts">NAD Concepts</a> status.</em></p>
<h3 id="1063"><a href="lwg-closed.html#1063">1063</a>. 03 iterator compatibilty</h3>
<p><b>Section:</b> 99 [iterator.backward] <b>Status:</b> <a href="lwg-active.html#NAD_Concepts">NAD Concepts</a>
 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-15 <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#NAD Concepts">NAD Concepts</a> status.</p>
<p><b>Discussion:</b></p>

<p>
Which header must a user <code>#include</code> to obtain the library-supplied
<code>concept_maps</code> declared in this paragraph?
</p>

<p>
This is important information, as existing user code will break if this
header is not included, and we should make a point of mandating this header
is <code>#include</code>-d by library headers likely to make use of it, notably
<code>&lt;algorithm&gt;</code>.  See issue <a href="lwg-closed.html#1001" title="Pointers, concepts and headers (Status: NAD Concepts)">1001</a><sup><a href="https://cplusplus.github.io/LWG/issue1001" title="Latest snapshot">(i)</a></sup> for more details.
</p>

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

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

<p><i>[
2009-07 Frankfurt
]</i></p>


<blockquote><p>
We believe this is NAD Concepts, but this needs to be reviewed against the
post-remove-concepts draft.
</p></blockquote>


<p id="res-1063"><b>Proposed resolution:</b></p>
<p><i>Change  [depr.lib.iterator.primitives], Iterator primitives, as
indicated:</i></p>

<blockquote>
  <p>To simplify the use of iterators and provide backward compatibility with
  previous C++ Standard Libraries,
  the library provides several classes and functions. <ins>Unless otherwise
  specified, these classes and functions shall be defined in header <code>&lt;iterator&gt;</code>.</ins></p>
</blockquote>
<p><i>Change 99 [iterator.backward], Iterator backward compatibility, as
indicated:</i></p>
<blockquote>
  <p>The library provides concept maps that allow iterators specified with
  <code>iterator_traits</code> to interoperate with
  algorithms that require iterator concepts. <ins>These concept maps shall be
  defined in the same header that defines the iterator.</ins> [<i>Example:</i></p>
</blockquote>





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