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<title>Issue 41: Ios_base needs clear(), exceptions()</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="41"><a href="lwg-defects.html#41">41</a>. Ios_base needs clear(), exceptions()</h3>
<p><b>Section:</b> 31.5.2 <a href="https://wg21.link/ios.base">[ios.base]</a> <b>Status:</b> <a href="lwg-active.html#TC1">TC1</a>
 <b>Submitter:</b> Nathan Myers <b>Opened:</b> 1998-08-06 <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#ios.base">issues</a> in [ios.base].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#TC1">TC1</a> status.</p>
<p><b>Duplicate of:</b> <a href="lwg-closed.html#157" title="Meaningless error handling for pword() and iword() (Status: Dup)">157</a></p>
<p><b>Discussion:</b></p>
<p>The description of ios_base::iword() and pword() in 31.5.2.5 <a href="https://wg21.link/ios.members.static">[ios.members.static]</a>, say that if they fail, they &quot;set badbit,
which may throw an exception&quot;. However, ios_base offers no
interface to set or to test badbit; those interfaces are defined in
basic_ios&lt;&gt;. </p>


<p id="res-41"><b>Proposed resolution:</b></p>
<p>Change the description in 31.5.2.6 <a href="https://wg21.link/ios.base.storage">[ios.base.storage]</a> in
paragraph 2, and also in paragraph 4, as follows. Replace</p>

<blockquote>
  <p>If the function fails it sets badbit, which may throw an exception.</p>
</blockquote>

<p>with</p>

<blockquote>
  <p>If the function fails, and <code>*this</code> is a base sub-object of
  a <code>basic_ios&lt;&gt;</code> object or sub-object, the effect is
  equivalent to calling <code>basic_ios&lt;&gt;::setstate(badbit)</code>
  on the derived object (which may throw <code>failure</code>).</p>
</blockquote>

<p><i>[Kona: LWG reviewed wording; setstate(failbit) changed to
setstate(badbit).]</i></p>







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