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<title>Issue 2790: Missing specification of istreambuf_iterator::operator-&gt;</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="2790"><a href="lwg-defects.html#2790">2790</a>. Missing specification of <code>istreambuf_iterator::operator-&gt;</code></h3>
<p><b>Section:</b> 24.6.4 <a href="https://wg21.link/istreambuf.iterator">[istreambuf.iterator]</a> <b>Status:</b> <a href="lwg-active.html#C++17">C++17</a>
 <b>Submitter:</b> Jonathan Wakely <b>Opened:</b> 2016-11-09 <b>Last modified:</b> 2017-07-30</p>
<p><b>Priority: </b>3
</p>
<p><b>View other</b> <a href="lwg-index-open.html#istreambuf.iterator">active issues</a> in [istreambuf.iterator].</p>
<p><b>View all other</b> <a href="lwg-index.html#istreambuf.iterator">issues</a> in [istreambuf.iterator].</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>
<b>Addresses GB 59</b>
<p/>
There is no specification for <code>istreambuf_iterator::operator-&gt;</code>. This 
operator appears to have been added for C++11 by LWG issue <a href="lwg-defects.html#659" title="istreambuf_iterator should have an operator-&gt;() (Status: C++11)">659</a><sup><a href="https://cplusplus.github.io/LWG/issue659" title="Latest snapshot">(i)</a></sup>, 
which gave the signature, but also lacked specification.
</p>

<p><i>[2016-11-08, Jonathan comments and suggests wording]</i></p>

<p>
There is no good option here, and implementations either return
<code>nullptr</code>, or return the address of a temporary, or don't even provide
the member at all. We took polls to decide whether to remove
<code>istreambuf_iterator::operator-&gt;</code>, or specify it to return <code>nullptr</code>, and
the preferred option was to remove it. It was noted that in the Ranges
TS input iterators no longer require <code>operator-&gt;</code> anyway, and the
library never tries to use it.
</p>

<p><i>[Issues Telecon 16-Dec-2016]</i></p>

<p>Move to Review</p>


<p id="res-2790"><b>Proposed resolution:</b></p>
<p>This wording is relative to N4606.</p>

<blockquote class="note">
<p>
This reverts LWG <a href="lwg-defects.html#659" title="istreambuf_iterator should have an operator-&gt;() (Status: C++11)">659</a><sup><a href="https://cplusplus.github.io/LWG/issue659" title="Latest snapshot">(i)</a></sup>.
</p>
</blockquote>

<ol>
<li><p>Remove the note in paragraph 1 of 24.6.4 <a href="https://wg21.link/istreambuf.iterator">[istreambuf.iterator]</a>:</p>
<blockquote>
<p>
The class template <code>istreambuf_iterator</code> defines an input iterator (24.2.3) that reads successive characters
from the streambuf for which it was constructed. <code>operator*</code> provides access to the current input character, if
any. <del>[<i>Note:</i> <code>operator-&gt;</code> may return a proxy. &mdash; <i>end note</i>]</del> Each time <code>operator++</code> 
is evaluated, the iterator advances to the next input character. [&hellip;]
</p>
</blockquote>
</li>

<li><p>Remove the member from the class synopsis in 24.6.4 <a href="https://wg21.link/istreambuf.iterator">[istreambuf.iterator]</a>:</p>

<blockquote>
<pre>
charT operator*() const;
<del>pointer operator-&gt;() const;</del>
istreambuf_iterator&amp; operator++();
proxy operator++(int);
</pre>
</blockquote>
</li>
</ol>





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