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<title>Issue 172: Inconsistent types for basic_istream::ignore()</title>
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<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#TC1">TC1</a> status.</em></p>
<h3 id="172"><a href="lwg-defects.html#172">172</a>. Inconsistent types for <code>basic_istream::ignore()</code></h3>
<p><b>Section:</b> 31.7.5.4 <a href="https://wg21.link/istream.unformatted">[istream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#TC1">TC1</a>
 <b>Submitter:</b> Greg Comeau, Dietmar K&uuml;hl <b>Opened:</b> 1999-07-23 <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#istream.unformatted">issues</a> in [istream.unformatted].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#TC1">TC1</a> status.</p>
<p><b>Discussion:</b></p>
<p>In 31.7.5.2 <a href="https://wg21.link/istream">[istream]</a> the function
<code>ignore()</code> gets an object of type <code>streamsize</code> as first
argument. However, in 31.7.5.4 <a href="https://wg21.link/istream.unformatted">[istream.unformatted]</a>
paragraph 23 the first argument is of type <code>int.</code></p>

<p>As far as I can see this is not really a contradiction because
everything is consistent if <code>streamsize</code> is typedef to be
<code>int</code>. However, this is almost certainly not what was
intended. The same thing happened to <code>basic_filebuf::setbuf()</code>,
as described in issue <a href="lwg-defects.html#173" title="Inconsistent types for basic_filebuf::setbuf() (Status: TC1)">173</a><sup><a href="https://cplusplus.github.io/LWG/issue173" title="Latest snapshot">(i)</a></sup>.</p>

<p>Darin Adler also
submitted this issue, commenting: Either 27.6.1.1 should be modified
to show a first parameter of type int, or 27.6.1.3 should be modified
to show a first parameter of type streamsize and use
numeric_limits&lt;streamsize&gt;::max.</p>


<p id="res-172"><b>Proposed resolution:</b></p>
<p>In 31.7.5.4 <a href="https://wg21.link/istream.unformatted">[istream.unformatted]</a> paragraph 23 and 24, change both uses
of <code>int</code> in the description of <code>ignore()</code> to
<code>streamsize</code>.</p>




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