<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Issue 633: Return clause mentions undefined "type()"</title>
<meta property="og:title" content="Issue 633: Return clause mentions undefined &quot;type()&quot;">
<meta property="og:description" content="C++ library issue. Status: NAD Editorial">
<meta property="og:url" content="https://cplusplus.github.io/LWG/issue633.html">
<meta property="og:type" content="website">
<meta property="og:image" content="http://cplusplus.github.io/LWG/images/cpp_logo.png">
<meta property="og:image:alt" content="C++ logo">
<style>
  p {text-align:justify}
  li {text-align:justify}
  pre code.backtick::before { content: "`" }
  pre code.backtick::after { content: "`" }
  blockquote.note
  {
    background-color:#E0E0E0;
    padding-left: 15px;
    padding-right: 15px;
    padding-top: 1px;
    padding-bottom: 1px;
  }
  ins {background-color:#A0FFA0}
  del {background-color:#FFA0A0}
  table.issues-index { border: 1px solid; border-collapse: collapse; }
  table.issues-index th { text-align: center; padding: 4px; border: 1px solid; }
  table.issues-index td { padding: 4px; border: 1px solid; }
  table.issues-index td:nth-child(1) { text-align: right; }
  table.issues-index td:nth-child(2) { text-align: left; }
  table.issues-index td:nth-child(3) { text-align: left; }
  table.issues-index td:nth-child(4) { text-align: left; }
  table.issues-index td:nth-child(5) { text-align: center; }
  table.issues-index td:nth-child(6) { text-align: center; }
  table.issues-index td:nth-child(7) { text-align: left; }
  table.issues-index td:nth-child(5) span.no-pr { color: red; }
  @media (prefers-color-scheme: dark) {
     html {
        color: #ddd;
        background-color: black;
     }
     ins {
        background-color: #225522
     }
     del {
        background-color: #662222
     }
     a {
        color: #6af
     }
     a:visited {
        color: #6af
     }
     blockquote.note
     {
        background-color: rgba(255, 255, 255, .10)
     }
  }
</style>
</head>
<body>
<hr>
<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">NAD Editorial</a> status.</em></p>
<h3 id="633"><a href="lwg-closed.html#633">633</a>. Return clause mentions undefined "type()"</h3>
<p><b>Section:</b> 22.10.17.3.6 <a href="https://wg21.link/func.wrap.func.targ">[func.wrap.func.targ]</a> <b>Status:</b> <a href="lwg-active.html#NAD_Editorial">NAD Editorial</a>
 <b>Submitter:</b> Daniel Kr&uuml;gler <b>Opened:</b> 2007-02-03 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#func.wrap.func.targ">issues</a> in [func.wrap.func.targ].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#NAD Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
22.10.17.3.6 <a href="https://wg21.link/func.wrap.func.targ">[func.wrap.func.targ]</a>, p4 says:
</p>
<blockquote><p>
<i>Returns:</i> If <code>type() == typeid(T)</code>, a pointer to the stored
function target; otherwise a null pointer.
</p></blockquote>

<ol>
<li>
There exists neither a type, a typedef <code>type</code>, nor member
function <code>type()</code> in class template function nor in the global or
<code>std</code> namespace.
</li>
<li>
Assuming that <code>type</code> should have been <code>target_type()</code>,
this description would lead to false results, if <code>T = <i>cv</i>
void</code> due to returns clause 22.10.17.3.6 <a href="https://wg21.link/func.wrap.func.targ">[func.wrap.func.targ]</a>, p1.
</li>
</ol>



<p id="res-633"><b>Proposed resolution:</b></p>
<p>
Change 22.10.17.3.6 <a href="https://wg21.link/func.wrap.func.targ">[func.wrap.func.targ]</a>, p4:
</p>

<blockquote><p>
<i>Returns:</i> If <code><del>type()</del> <ins>target_type()</ins> == typeid(T) <ins>&amp;&amp; typeid(T) !=
typeid(void)</ins></code>, a pointer to the stored function target;
otherwise a null pointer.
</p></blockquote>

<p><i>[
Pete: Agreed. It's editorial, so I'll fix it.
]</i></p>







</body>
</html>
