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<title>Issue 2576: istream_iterator and ostream_iterator should use std::addressof</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++17">C++17</a> status.</em></p>
<h3 id="2576"><a href="lwg-defects.html#2576">2576</a>. <code>istream_iterator</code> and <code>ostream_iterator</code> should use <code>std::addressof</code></h3>
<p><b>Section:</b> 24.6 <a href="https://wg21.link/stream.iterators">[stream.iterators]</a> <b>Status:</b> <a href="lwg-active.html#C++17">C++17</a>
 <b>Submitter:</b> Tim Song <b>Opened:</b> 2016-01-01 <b>Last modified:</b> 2017-07-30</p>
<p><b>Priority: </b>0
</p>
<p><b>View all other</b> <a href="lwg-index.html#stream.iterators">issues</a> in [stream.iterators].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++17">C++17</a> status.</p>
<p><b>Discussion:</b></p>
<p>
To defend against overloaded unary <code>&amp;</code>. This includes the constructors of both iterators, and 
<code>istream_iterator::operator-&gt;</code>.
<p/>
Note that <code>{i,o}stream_type</code> are specializations of <code>basic_{i,o}stream</code>, but the constructors might still 
pick up an overloaded <code>&amp;</code> via the <code>traits</code> template parameter. This change also provides consistency 
with <code>std::experimental::ostream_joiner</code> (which uses <code>std::addressof</code>).
</p>

<p><i>[2016-02, Issues Telecon]</i></p>

<p>
P0; move to Tentatively Ready.
</p>


<p id="res-2576"><b>Proposed resolution:</b></p>
<p>
This wording is relative to N4567.
</p>

<ol>
<li><p>Edit 24.6.2.2 <a href="https://wg21.link/istream.iterator.cons">[istream.iterator.cons]</a>/3+4 as indicated:</p>

<blockquote>
<pre>
istream_iterator(istream_type&amp; s);
</pre>
<blockquote>
<p>
-3- <i>Effects</i>: Initializes <code>in_stream</code> with <code><del>&amp;s</del><ins>addressof(s)</ins></code>. <code>value</code> 
may be initialized during construction or the first time it is referenced.
<p/>
-4- <i>Postcondition</i>: <code>in_stream == <del>&amp;s</del><ins>addressof(s)</ins></code>.
</p>
</blockquote>
</blockquote>

</li>

<li><p>Edit 24.6.2.3 <a href="https://wg21.link/istream.iterator.ops">[istream.iterator.ops]</a>/2 as indicated:</p>

<blockquote>
<pre>
const T* operator-&gt;() const;
</pre>
<blockquote>
<p>
-2- <i>Returns</i>: <code><del>&amp;</del><ins>addressof</ins>(operator*())</code>.
</p>
</blockquote>
</blockquote>

</li>

<li><p>Edit 24.6.3.2 <a href="https://wg21.link/ostream.iterator.cons.des">[ostream.iterator.cons.des]</a>/1+2 as indicated:</p>

<blockquote>
<pre>
ostream_iterator(ostream_type&amp; s);
</pre>
<blockquote>
<p>
-1- <i>Effects</i>: Initializes <code>out_stream</code> with <code><del>&amp;s</del><ins>addressof(s)</ins></code> and 
<code>delim</code> with null.
</p>
</blockquote>
<pre>
ostream_iterator(ostream_type&amp; s, const charT* delimiter);
</pre>
<blockquote>
<p>
-2- <i>Effects</i>: Initializes <code>out_stream</code> with <code><del>&amp;s</del><ins>addressof(s)</ins></code> and 
<code>delim</code> with <code>delimiter</code>.
</p>
</blockquote>
</blockquote>

</li>

</ol>





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