<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Issue 4129: Possibly incorrect wording for data race avoidance</title>
<meta property="og:title" content="Issue 4129: Possibly incorrect wording for data race avoidance">
<meta property="og:description" content="C++ library issue. Status: New">
<meta property="og:url" content="https://cplusplus.github.io/LWG/issue4129.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="4129"><a href="lwg-active.html#4129">4129</a>. Possibly incorrect wording for data race avoidance</h3>
<p><b>Section:</b> 16.4.6.10 <a href="https://wg21.link/res.on.data.races">[res.on.data.races]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a>
 <b>Submitter:</b> Jiang An <b>Opened:</b> 2024-07-30 <b>Last modified:</b> 2024-08-03</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View other</b> <a href="lwg-index-open.html#res.on.data.races">active issues</a> in [res.on.data.races].</p>
<p><b>View all other</b> <a href="lwg-index.html#res.on.data.races">issues</a> in [res.on.data.races].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
From PR <a href="https://github.com/cplusplus/draft/pull/6748">cplusplus/draft#6748</a> 
which was closed as non-editorial.
<p/>
Currently, 16.4.6.10 <a href="https://wg21.link/res.on.data.races">[res.on.data.races]</a> is talking about arguments and "including <code>this</code>", 
but <code>this</code> is not a function argument. Moreover, it seems more appropriate to say that a function 
accesses some object via a parameter.
<p/>
It might need to be considered whether we should use the more general term "range" instead of "container", 
which will cover <code>std::span</code>, etc.
</p>


<p id="res-4129"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/N4986" title=" Working Draft, Programming Languages — C++">N4986</a>.
</p>

<ol>
<li><p>Modify 16.4.6.10 <a href="https://wg21.link/res.on.data.races">[res.on.data.races]</a> as indicated:</p>

<blockquote>
<p>
-2- A C++ standard library function shall not directly or indirectly access objects 
(6.10.2 <a href="https://wg21.link/intro.multithread">[intro.multithread]</a>) accessible by threads other than the current thread 
unless the objects are accessed directly or indirectly via the function's 
<del>arguments</del><ins>parameters</ins>, including <del><code>this</code></del><ins>the 
object parameter (if any)</ins>.
<p/>
-3- A C++ standard library function shall not directly or indirectly modify objects 
(6.10.2 <a href="https://wg21.link/intro.multithread">[intro.multithread]</a>) accessible by threads other than the current thread 
unless the objects are accessed directly or indirectly via the function's non-const
<del>arguments</del><ins>parameters</ins>, including <del><code>this</code></del><ins>the 
object parameter (if any)</ins>.
<p/>
[&hellip;]
<p/>
-5- A C++ standard library function shall not access objects indirectly accessible via 
its <del>arguments</del><ins>parameters</ins> or via elements of its container 
<del>arguments</del><ins>parameters</ins> except by invoking functions required by its 
specification on those container elements.
</p>
</blockquote>

</li>

</ol>





</body>
</html>
