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<title>Issue 2515: [fund.ts.v2] Certain comparison operators of observer_ptr do not match synopsis</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#TS">TS</a> status.</em></p>
<h3 id="2515"><a href="lwg-defects.html#2515">2515</a>. [fund.ts.v2] Certain comparison operators of <code>observer_ptr</code> do not match synopsis</h3>
<p><b>Section:</b> 8.12.6 <a href="https://cplusplus.github.io/fundamentals-ts/v2.html#memory.observer.ptr.special">[fund.ts.v2::memory.observer.ptr.special]</a> <b>Status:</b> <a href="lwg-active.html#TS">TS</a>
 <b>Submitter:</b> Tim Song <b>Opened:</b> 2015-07-07 <b>Last modified:</b> 2017-07-30</p>
<p><b>Priority: </b>0
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#TS">TS</a> status.</p>
<p><b>Discussion:</b></p>
<p><b>Addresses: fund.ts.v2</b></p>
<p>
In <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4529.html">N4529</a> 
[memory.observer.ptr.special] paragraphs 15, 17 and 19, the <code>&gt;</code>, <code>&lt;=</code> and 
<code>&gt;=</code> operators of <code>observer_ptr</code> are shown as
</p>
<blockquote><pre>
template &lt;class W&gt; 
bool operator>(observer_ptr&lt;W&gt; p1, observer_ptr&lt;W&gt; p2);
</pre></blockquote>
<p>
whereas in [header.memory.synop] they are shown as
</p>
<blockquote><pre>
template &lt;class W1, class W2&gt; 
bool operator>(observer_ptr&lt;W1&gt; p1, observer_ptr&lt;W2&gt; p2);
</pre></blockquote>
<p>
Given that the specification of <code>operator&lt;</code> took special care to support hetergeneous types, 
presumably the second version is intended.
</p>

<p><i>[2015-07, Telecon]</i></p>

<p>
Move to Tentatively Ready.
</p>


<p id="res-2515"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4529.html">N4529</a>.
</p>

<ol>
<li><p>Edit 8.12.6 <a href="https://cplusplus.github.io/fundamentals-ts/v2.html#memory.observer.ptr.special">[fund.ts.v2::memory.observer.ptr.special]</a> as indicated:</p>

<blockquote>
<pre>-15- template &lt;class W<ins>1, class W2</ins>&gt;
bool operator&gt;(observer_ptr&lt;W<ins>1</ins>&gt; p1, observer_ptr&lt;W<ins>2</ins>&gt; p2);
</pre>
<blockquote><p>
[&hellip;]
</p></blockquote>
<pre>
-17- template &lt;class W<ins>1, class W2</ins>&gt;
bool operator&lt;=(observer_ptr&lt;W<ins>1</ins>&gt; p1, observer_ptr&lt;W<ins>2</ins>&gt; p2);
</pre>
<blockquote><p>
[&hellip;]
</p></blockquote>
<pre>
-19- template &lt;class W<ins>1, class W2</ins>&gt;
bool operator&gt;=(observer_ptr&lt;W<ins>1</ins>&gt; p1, observer_ptr&lt;W<ins>2</ins>&gt; p2);
</pre>
</blockquote>
</li>
</ol>





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