<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Issue 3093: LWG 2294/2192 missed a std::abs overload</title>
<meta property="og:title" content="Issue 3093: LWG 2294/2192 missed a std::abs overload">
<meta property="og:description" content="C++ library issue. Status: New">
<meta property="og:url" content="https://cplusplus.github.io/LWG/issue3093.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="3093"><a href="lwg-active.html#3093">3093</a>. LWG 2294/2192 missed a <code>std::abs</code> overload</h3>
<p><b>Section:</b> 29.7.2 <a href="https://wg21.link/c.math.abs">[c.math.abs]</a>, 17.2.2 <a href="https://wg21.link/cstdlib.syn">[cstdlib.syn]</a>, 31.13.2 <a href="https://wg21.link/cinttypes.syn">[cinttypes.syn]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a>
 <b>Submitter:</b> Richard Smith <b>Opened:</b> 2018-03-30 <b>Last modified:</b> 2018-06-19</p>
<p><b>Priority: </b>3
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
LWG <a href="lwg-defects.html#2192" title="Validity and return type of std::abs(0u) is unclear (Status: C++17)">2192</a><sup><a href="https://cplusplus.github.io/LWG/issue2192" title="Latest snapshot">(i)</a></sup> changed the library specification so that you always get all the <code>std::abs</code> overloads for fundamental 
types if you get any of them.
<p/>
Except that it missed one: <code>&lt;cinttypes&gt;</code> provides a <code>std::abs</code> (and <code>std::div</code>) overload for 
<code>intmax_t</code> if it's not <code>long long</code> (since LWG <a href="lwg-defects.html#1449" title="Incomplete specification of header &lt;cinttypes&gt; (Status: C++11)">1449</a><sup><a href="https://cplusplus.github.io/LWG/issue1449" title="Latest snapshot">(i)</a></sup>). Presumably that one should also follow the 
<code>&lt;cstdlib&gt;</code>/<code>&lt;cmath&gt;</code> pattern and we should make the complete <code>abs</code> overload set available 
whenever any of the three headers is included? (And likewise we should make the complete <code>std::div</code> overload set 
available whenever either <code>&lt;cstdlib&gt;</code> or <code>&lt;cinttypes&gt;</code> is included.)
</p>

<p><i>[2018-06-18 after reflector discussion]</i></p>

<p>Priority set to 3</p>



<p id="res-3093"><b>Proposed resolution:</b></p>





</body>
</html>
