<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Issue 216: setbase manipulator description flawed</title>
<meta property="og:title" content="Issue 216: setbase manipulator description flawed">
<meta property="og:description" content="C++ library issue. Status: Dup">
<meta property="og:url" content="https://cplusplus.github.io/LWG/issue216.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#Dup">Dup</a> status.</em></p>
<h3 id="216"><a href="lwg-closed.html#216">216</a>. setbase manipulator description flawed</h3>
<p><b>Section:</b> 31.7.7 <a href="https://wg21.link/std.manip">[std.manip]</a> <b>Status:</b> <a href="lwg-active.html#Dup">Dup</a>
 <b>Submitter:</b> Hyman Rosen <b>Opened:</b> 2000-02-29 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View other</b> <a href="lwg-index-open.html#std.manip">active issues</a> in [std.manip].</p>
<p><b>View all other</b> <a href="lwg-index.html#std.manip">issues</a> in [std.manip].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="lwg-defects.html#193" title="Heap operations description incorrect (Status: TC1)">193</a></p>
<p><b>Discussion:</b></p>
<p>31.7.7 <a href="https://wg21.link/std.manip">[std.manip]</a> paragraph 5 says:</p>
<blockquote>
<pre>smanip setbase(int base);</pre>
<p> Returns: An object s of unspecified type such that if out is an
(instance of) basic_ostream then the expression out&lt;&lt;s behaves
as if f(s) were called, in is an (instance of) basic_istream then the
expression in&gt;&gt;s behaves as if f(s) were called. Where f can be
defined as:</p>
<pre>ios_base&amp; f(ios_base&amp; str, int base)
{
  // set basefield
  str.setf(n == 8 ? ios_base::oct :
                n == 10 ? ios_base::dec :
                n == 16 ? ios_base::hex :
                  ios_base::fmtflags(0), ios_base::basefield);
  return str;
}</pre>
</blockquote>
<p>There are two problems here. First, f takes two parameters, so the
description needs to say that out&lt;&lt;s and in&gt;&gt;s behave as if f(s,base)
had been called. Second, f is has a parameter named base, but is written as if
the parameter was named n.</p>
<p>Actually, there's a third problem. The paragraph has grammatical errors.
There needs to be an &quot;and&quot; after the first comma, and the &quot;Where
f&quot; sentence fragment needs to be merged into its preceding sentence. You
may also want to format the function a little better. The formatting above is
more-or-less what the Standard contains.</p>


<p><b>Rationale:</b></p>
<p>The resolution of this defect is subsumed by the proposed resolution for
issue <a href="lwg-defects.html#193" title="Heap operations description incorrect (Status: TC1)">193</a><sup><a href="https://cplusplus.github.io/LWG/issue193" title="Latest snapshot">(i)</a></sup>.</p>

<p><i>[Tokyo: The LWG agrees that this is a defect and notes that it
occurs additional places in the section, all requiring fixes.]</i></p>








</body>
</html>
