<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Issue 3906: "Undefined address" is undefined</title>
<meta property="og:title" content="Issue 3906: &quot;Undefined address&quot; is undefined">
<meta property="og:description" content="C++ library issue. Status: New">
<meta property="og:url" content="https://cplusplus.github.io/LWG/issue3906.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#New">New</a> status.</em></p>
<h3 id="3906"><a href="lwg-active.html#3906">3906</a>. "Undefined address" is undefined</h3>
<p><b>Section:</b> 32.5.8.5 <a href="https://wg21.link/atomics.types.pointer">[atomics.types.pointer]</a>, 32.5.7.5 <a href="https://wg21.link/atomics.ref.pointer">[atomics.ref.pointer]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a>
 <b>Submitter:</b> Jiang An <b>Opened:</b> 2023-03-18 <b>Last modified:</b> 2023-05-24</p>
<p><b>Priority: </b>3
</p>
<p><b>View other</b> <a href="lwg-index-open.html#atomics.types.pointer">active issues</a> in [atomics.types.pointer].</p>
<p><b>View all other</b> <a href="lwg-index.html#atomics.types.pointer">issues</a> in [atomics.types.pointer].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
This was originally <a href="https://github.com/cplusplus/draft/issues/6185">editorial issue #6185</a>.
<p/>
The term "undefined address" is used in 32.5.8.5 <a href="https://wg21.link/atomics.types.pointer">[atomics.types.pointer]</a>/8 and 
32.5.7.5 <a href="https://wg21.link/atomics.ref.pointer">[atomics.ref.pointer]</a>/6, however, it seems not properly defined and the intended meaning is unclear.
The term originally appeared in the paper <a href="https://wg21.link/N2393" title=" C++ Atomic Types and Operations">N2393</a> and was reused by <a href="https://wg21.link/P0019R8" title=" Atomic Ref">P0019R8</a>, but 
no explanation can be found in these papers.
<p/>
Perhaps "undefined address" is related to the undefined behavior specified in 7.6.6 <a href="https://wg21.link/expr.add">[expr.add]</a>.
</p>

<p><i>[2023-05-24; Reflector poll]</i></p>

<p>
Set priority to 3 after reflector poll.
</p>



<p id="res-3906"><b>Proposed resolution:</b></p>





</body>
</html>
