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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html><head><title>C++ Standard Library Closed Issues List</title>
<style type="text/css">
p {text-align:justify}
li {text-align:justify}
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<table>
<tbody><tr>
<td align="left">Doc. no.</td>
<td align="left">N2458=07-0328</td>
</tr>
<tr>
<td align="left">Date:</td>
<td align="left">2007-10-20</td>
</tr>
<tr>
<td align="left">Project:</td>
<td align="left">Programming Language C++</td>
</tr>
<tr>
<td align="left">Reply to:</td>
<td align="left">Howard Hinnant <<a href="mailto:howard.hinnant@gmail.com">howard.hinnant@gmail.com</a>></td>
</tr>
</tbody></table>
<h1>C++ Standard Library Closed Issues List (Revision R52)</h1>
<p>Reference ISO/IEC IS 14882:1998(E)</p>
<p>Also see:</p>
<ul>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-toc.html">Table of Contents</a> for all library issues.</li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html">Index by Section</a> for all library issues.</li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html">Index by Status</a> for all library issues.</li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html">Library Active Issues List</a></li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html">Library Defect Reports List</a></li>
</ul>
<p>This document contains only library issues which have been closed
by the Library Working Group as duplicates or not defects. That is,
issues which have a status of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a> or
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>. See the <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html">Library Active Issues List</a> active issues and more
information. See the <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html">Library Defect Reports List</a> for issues considered
defects. The introductory material in that document also applies to
this document.</p>
<h2>Revision History</h2>
<ul>
<li>R52:
2007-10-19 post-Kona mailing.
<ul>
<li><b>Summary:</b><ul>
<li>172 open issues, up by 4.</li>
<li>582 closed issues, up by 27.</li>
<li>754 issues total, up by 31.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#725">725</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#726">726</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#728">728</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#729">729</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#730">730</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#731">731</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#732">732</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#733">733</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#734">734</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#735">735</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#736">736</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#737">737</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#738">738</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#739">739</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#740">740</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#741">741</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#742">742</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#743">743</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#744">744</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#745">745</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#746">746</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#747">747</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#748">748</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#749">749</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#750">750</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#751">751</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#752">752</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#753">753</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#754">754</a>.</li>
<li>Changed the following issues from NAD Future to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#77">77</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>.</li>
<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#639">639</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#657">657</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#663">663</a>.</li>
<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#548">548</a>.</li>
<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#546">546</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#550">550</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#564">564</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#565">565</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#573">573</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#585">585</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#588">588</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#627">627</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#630">630</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#632">632</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#635">635</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#653">653</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#659">659</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#667">667</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#668">668</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#669">669</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#670">670</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#671">671</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#673">673</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#686">686</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#704">704</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#707">707</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#708">708</a>.</li>
<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#393">393</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#592">592</a>.</li>
<li>Changed the following issues from New to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#607">607</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#608">608</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#654">654</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#655">655</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#677">677</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#682">682</a>.</li>
<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#561">561</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#562">562</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#563">563</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#567">567</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#581">581</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#595">595</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#620">620</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#621">621</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#622">622</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#623">623</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#624">624</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#661">661</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#664">664</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#665">665</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#666">666</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#674">674</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#679">679</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#687">687</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#688">688</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#689">689</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#693">693</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#694">694</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#695">695</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#700">700</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#703">703</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#705">705</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#706">706</a>.</li>
<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#680">680</a>.</li>
<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#574">574</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#596">596</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#618">618</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#638">638</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#645">645</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#684">684</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#685">685</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#691">691</a>.</li>
<li>Changed the following issues from New to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#552">552</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#634">634</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#650">650</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#651">651</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#652">652</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#678">678</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#681">681</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#699">699</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#712">712</a>.</li>
<li>Changed the following issues from Open to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#401">401</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#524">524</a>.</li>
<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#577">577</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#660">660</a>.</li>
</ul></li>
</ul>
</li>
<li>R51:
2007-09-09 pre-Kona mailing.
<ul>
<li><b>Summary:</b><ul>
<li>168 open issues, up by 15.</li>
<li>555 closed issues, up by 0.</li>
<li>723 issues total, up by 15.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#709">709</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#710">710</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#711">711</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#712">712</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#713">713</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#714">714</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#715">715</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#716">716</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#717">717</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#718">718</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#719">719</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#720">720</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#721">721</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#722">722</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#723">723</a>.</li>
</ul></li>
</ul>
</li>
<li>R50:
2007-08-05 post-Toronto mailing.
<ul>
<li><b>Summary:</b><ul>
<li>153 open issues, down by 5.</li>
<li>555 closed issues, up by 17.</li>
<li>708 issues total, up by 12.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#697">697</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#698">698</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#699">699</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#700">700</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#701">701</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#702">702</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#703">703</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#704">704</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#705">705</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#706">706</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#707">707</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#708">708</a>.</li>
<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#583">583</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#584">584</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#662">662</a>.</li>
<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#528">528</a>.</li>
<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#637">637</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#647">647</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#658">658</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#690">690</a>.</li>
<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#525">525</a>.</li>
<li>Changed the following issues from Pending NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#633">633</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#636">636</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#641">641</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#642">642</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#648">648</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#649">649</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#656">656</a>.</li>
<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#579">579</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#680">680</a>.</li>
<li>Changed the following issues from Pending WP to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>.</li>
<li>Changed the following issues from Ready to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#644">644</a>.</li>
<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#577">577</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#660">660</a>.</li>
<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a>.</li>
<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#518">518</a>.</li>
<li>Changed the following issues from Ready to TRDec: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a>.</li>
<li>Changed the following issues from DR to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#453">453</a>.</li>
<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#566">566</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#628">628</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#640">640</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#643">643</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#646">646</a>.</li>
</ul></li>
</ul>
</li>
<li>R49:
2007-06-23 pre-Toronto mailing.
<ul>
<li><b>Summary:</b><ul>
<li>158 open issues, up by 13.</li>
<li>538 closed issues, up by 7.</li>
<li>696 issues total, up by 20.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#677">677</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#678">678</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#679">679</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#680">680</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#681">681</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#682">682</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#684">684</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#685">685</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#686">686</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#687">687</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#688">688</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#689">689</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#690">690</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#691">691</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#692">692</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#693">693</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#694">694</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#695">695</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#696">696</a>.</li>
<li>Added the following Pending NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#683">683</a>.</li>
<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#587">587</a>.</li>
<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#590">590</a>.</li>
<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#636">636</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#642">642</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#648">648</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#649">649</a>.</li>
</ul></li>
</ul>
</li>
<li>R48:
2007-05-06 post-Oxford mailing.
<ul>
<li><b>Summary:</b><ul>
<li>145 open issues, down by 33.</li>
<li>531 closed issues, up by 53.</li>
<li>676 issues total, up by 20.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#657">657</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#658">658</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#659">659</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#660">660</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#661">661</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#662">662</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#663">663</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#664">664</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#665">665</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#666">666</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#667">667</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#668">668</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#669">669</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#670">670</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#671">671</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#673">673</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#674">674</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>.</li>
<li>Changed the following issues from Tentatively Ready to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#479">479</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>.</li>
<li>Changed the following issues from Tentatively Ready to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#385">385</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#466">466</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#470">470</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#547">547</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#560">560</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#572">572</a>.</li>
<li>Changed the following issues from NAD to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#351">351</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#357">357</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#368">368</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#499">499</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#555">555</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#558">558</a>.</li>
<li>Changed the following issues from Tentatively Ready to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#482">482</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#615">615</a>.</li>
<li>Changed the following issues from NAD_Future to NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#77">77</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#105">105</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#116">116</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#149">149</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#180">180</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#188">188</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#219">219</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#348">348</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#353">353</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#388">388</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#390">390</a>.</li>
<li>Changed the following issues from Tentatively Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>.</li>
<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#633">633</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#641">641</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#656">656</a>.</li>
<li>Changed the following issues from Tentatively Ready to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#594">594</a>.</li>
<li>Changed the following issues from Tentatively Ready to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>.</li>
<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#566">566</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#628">628</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#640">640</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#643">643</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#644">644</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#646">646</a>.</li>
<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a>.</li>
<li>Changed the following issues from Ready to TRDec: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#598">598</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#599">599</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#600">600</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#601">601</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#602">602</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#605">605</a>.</li>
<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#545">545</a>.</li>
<li>Changed the following issues from Tentatively Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#201">201</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#206">206</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#416">416</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#422">422</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#456">456</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#575">575</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#576">576</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#578">578</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#586">586</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#589">589</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#593">593</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#609">609</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#610">610</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#611">611</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#613">613</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#616">616</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#619">619</a>.</li>
</ul></li>
</ul>
</li>
<li>R47:
2007-03-09 pre-Oxford mailing.
<ul>
<li><b>Summary:</b><ul>
<li>178 open issues, up by 37.</li>
<li>478 closed issues, up by 0.</li>
<li>656 issues total, up by 37.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#620">620</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#621">621</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#622">622</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#623">623</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#624">624</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#627">627</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#628">628</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#630">630</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#632">632</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#633">633</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#634">634</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#635">635</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#636">636</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#637">637</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#638">638</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#639">639</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#640">640</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#641">641</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#642">642</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#643">643</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#644">644</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#645">645</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#646">646</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#647">647</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#648">648</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#649">649</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#650">650</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#651">651</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#652">652</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#653">653</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#654">654</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#655">655</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#656">656</a>.</li>
<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#625">625</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#626">626</a>.</li>
<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#570">570</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#580">580</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#582">582</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#590">590</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#612">612</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#614">614</a>.</li>
<li>Changed the following issues from New to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#547">547</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#560">560</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#572">572</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#575">575</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#576">576</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#578">578</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#586">586</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#589">589</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#593">593</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#594">594</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#609">609</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#610">610</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#611">611</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#613">613</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#615">615</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#616">616</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#619">619</a>.</li>
<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#201">201</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#206">206</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#385">385</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#416">416</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#422">422</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#456">456</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#466">466</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#470">470</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#479">479</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#482">482</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>.</li>
<li>Changed the following issues from Review to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a>.</li>
</ul></li>
</ul>
</li>
<li>R46:
2007-01-12 mid-term mailing.
<ul>
<li><b>Summary:</b><ul>
<li>141 open issues, up by 11.</li>
<li>478 closed issues, down by 1.</li>
<li>619 issues total, up by 10.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#610">610</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#619">619</a>.</li>
</ul></li>
</ul>
</li>
<li>R45:
2006-11-03 post-Portland mailing.
<ul>
<li><b>Summary:</b><ul>
<li>130 open issues, up by 0.</li>
<li>479 closed issues, up by 17.</li>
<li>609 issues total, up by 17.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#520">520</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#521">521</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a> to WP.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#554">554</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#555">555</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#558">558</a> to NAD.</li>
<li>Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Dup.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#518">518</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#523">523</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#524">524</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#557">557</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#597">597</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#606">606</a> to Open.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#545">545</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#598">598</a> - <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#605">605</a> to Ready.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a> to Review.</li>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#593">593</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#609">609</a>.</li>
</ul></li>
</ul>
</li>
<li>R44:
2006-09-08 pre-Portland mailing.
<ul>
<li><b>Summary:</b><ul>
<li>130 open issues, up by 6.</li>
<li>462 closed issues, down by 1.</li>
<li>592 issues total, up by 5.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#583">583</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#592">592</a>.</li>
</ul></li>
</ul>
</li>
<li>R43:
2006-06-23 mid-term mailing.
<ul>
<li><b>Summary:</b><ul>
<li>124 open issues, up by 14.</li>
<li>463 closed issues, down by 1.</li>
<li>587 issues total, up by 13.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#575">575</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#582">582</a>.</li>
<li>Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#255">255</a>.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#520">520</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Tentatively Ready.</li>
</ul></li>
</ul>
</li>
<li>R42:
2006-04-21 post-Berlin mailing.
<ul>
<li><b>Summary:</b><ul>
<li>110 open issues, down by 16.</li>
<li>464 closed issues, up by 24.</li>
<li>574 issues total, up by 8.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#567">567</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#572">572</a>.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#499">499</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#501">501</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#506">506</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#509">509</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#511">511</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#517">517</a> to NAD.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#502">502</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#503">503</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#522">522</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#525">525</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#529">529</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#548">548</a> to Open.</li>
<li>Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#521">521</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a> to Ready.</li>
<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#369">369</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#371">371</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#376">376</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#384">384</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#475">475</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#495">495</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#497">497</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#505">505</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#507">507</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#508">508</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#519">519</a> to WP.</li>
<li>Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a> to Review.</li>
</ul></li>
</ul>
</li>
<li>R41:
2006-02-24 pre-Berlin mailing.
<ul>
<li><b>Summary:</b><ul>
<li>126 open issues, up by 31.</li>
<li>440 closed issues, up by 0.</li>
<li>566 issues total, up by 31.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#566">566</a>.</li>
<li>Moved <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#342">342</a> from Ready to Open.</li>
<li>Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#309">309</a>.</li>
</ul></li>
</ul>
</li>
<li>R40:
2005-12-16 mid-term mailing.
<ul>
<li><b>Summary:</b><ul>
<li>95 open issues.</li>
<li>440 closed issues.</li>
<li>535 issues total.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#529">529</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>.</li>
</ul></li>
</ul>
</li>
<li>R39:
2005-10-14 post-Mont Tremblant mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#528">528</a>.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#280">280</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#461">461</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#464">464</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#465">465</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#467">467</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#468">468</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#474">474</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#496">496</a> from Ready to WP as per the vote from Mont Tremblant.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#342">342</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#369">369</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#371">371</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#376">376</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#384">384</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#475">475</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#495">495</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#497">497</a> from Review to Ready.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#498">498</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#506">506</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#509">509</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#510">510</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#511">511</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a> from New to Open.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#505">505</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#507">507</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#508">508</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#519">519</a> from New to Ready.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#500">500</a> from New to NAD.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#518">518</a> from New to Review.
</li>
<li>R38:
2005-07-03 pre-Mont Tremblant mailing.
Merged open TR1 issues in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#522">522</a>.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#523">523</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#523">523</a>
</li>
<li>R37:
2005-06 mid-term mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#498">498</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#503">503</a>.
</li>
<li>R36:
2005-04 post-Lillehammer mailing. All issues in "ready" status except
for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#454">454</a> were moved to "DR" status, and all issues
previously in "DR" status were moved to "WP".
</li>
<li>R35:
2005-03 pre-Lillehammer mailing.
</li>
<li>R34:
2005-01 mid-term mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#494">494</a>.
</li>
<li>R33:
2004-11 post-Redmond mailing. Reflects actions taken in Redmond.
</li>
<li>R32:
2004-09 pre-Redmond mailing: reflects new proposed resolutions and
new issues received after the 2004-07 mailing. Added
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#479">479</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#481">481</a>.
</li>
<li>R31:
2004-07 mid-term mailing: reflects new proposed resolutions and
new issues received after the post-Sydney mailing. Added
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>.
</li>
<li>R30:
Post-Sydney mailing: reflects decisions made at the Sydney meeting.
Voted all "Ready" issues from R29 into the working paper.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#460">460</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#462">462</a>.
</li>
<li>R29:
Pre-Sydney mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#441">441</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#457">457</a>.
</li>
<li>R28:
Post-Kona mailing: reflects decisions made at the Kona meeting.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#432">432</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#440">440</a>.
</li>
<li>R27:
Pre-Kona mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#404">404</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#431">431</a>.
</li>
<li>R26:
Post-Oxford mailing: reflects decisions made at the Oxford meeting.
All issues in Ready status were voted into DR status. All issues in
DR status were voted into WP status.
</li>
<li>R25:
Pre-Oxford mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#390">390</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#402">402</a>.
</li>
<li>R24:
Post-Santa Cruz mailing: reflects decisions made at the Santa Cruz
meeting. All Ready issues from R23 with the exception of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, which has been given a new proposed resolution, were
moved to DR status. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#383">383</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a>. (Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#387">387</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a> were discussed
at the meeting.) Made progress on issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a>: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a> have been moved to Ready status, and the only remaining
concerns with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a> involve wording.
</li>
<li>R23:
Pre-Santa Cruz mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#367">367</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#382">382</a>.
Moved issues in the TC to TC status.
</li>
<li>R22:
Post-Curaçao mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#366">366</a>.
</li>
<li>R21:
Pre-Curaçao mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#351">351</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#361">361</a>.
</li>
<li>R20:
Post-Redmond mailing; reflects actions taken in Redmond. Added
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#336">336</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, of which issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#347">347</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a> were added since Redmond, hence
not discussed at the meeting.
All Ready issues were moved to DR status, with the exception of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a>, and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>.
Noteworthy issues discussed at Redmond include
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#120">120</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#202">202</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>.
</li>
<li>R19:
Pre-Redmond mailing. Added new issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#335">335</a>.
</li>
<li>R18:
Post-Copenhagen mailing; reflects actions taken in Copenhagen.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#317">317</a>, and discussed
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a>.
Changed status of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#118">118</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#153">153</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#165">165</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#171">171</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#183">183</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#184">184</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#185">185</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#186">186</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#214">214</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#221">221</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#234">234</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#237">237</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#243">243</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#248">248</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#251">251</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#252">252</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#256">256</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#260">260</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#261">261</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#262">262</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#263">263</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#268">268</a>
to DR.
Changed status of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#117">117</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#182">182</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#230">230</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#238">238</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#242">242</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#259">259</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#266">266</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#272">272</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#273">273</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#275">275</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#281">281</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#285">285</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#286">286</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#288">288</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#292">292</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#295">295</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#297">297</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#298">298</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#301">301</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#303">303</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#306">306</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#307">307</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#308">308</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a>
to Ready.
Closed issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#277">277</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#279">279</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#287">287</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#289">289</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#293">293</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#302">302</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#313">313</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a>
as NAD.
</li>
<li>R17:
Pre-Copenhagen mailing. Converted issues list to XML. Added proposed
resolutions for issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#76">76</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#278">278</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#311">311</a>.
</li>
<li>R16:
post-Toronto mailing; reflects actions taken in Toronto. Added new
issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#277">277</a>. Changed status of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#3">3</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#8">8</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#9">9</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#19">19</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#26">26</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#31">31</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#61">61</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#63">63</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#108">108</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#115">115</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#122">122</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#142">142</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#144">144</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#146">146</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#147">147</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#159">159</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#164">164</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#170">170</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#181">181</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#208">208</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#209">209</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#210">210</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#217">217</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#220">220</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#222">222</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#223">223</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#224">224</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a> to "DR". Reopened issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#23">23</a>. Reopened
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#187">187</a>. Changed issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#2">2</a> and
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> to NAD. Fixed a typo in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a>. Fixed
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#70">70</a>: signature should be changed both places it
appears. Fixed issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#160">160</a>: previous version didn't fix
the bug in enough places.
</li>
<li>R15:
pre-Toronto mailing. Added issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a>. Some small HTML formatting
changes so that we pass Weblint tests.
</li>
<li>R14:
post-Tokyo II mailing; reflects committee actions taken in
Tokyo. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a>. (00-0019R1/N1242)
</li>
<li>R13:
pre-Tokyo II updated: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a>.
</li>
<li>R12:
pre-Tokyo II mailing: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a> to
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>. Added "and paragraph 5" to the proposed resolution
of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#29">29</a>. Add further rationale to issue
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#178">178</a>.
</li>
<li>R11:
post-Kona mailing: Updated to reflect LWG and full committee actions
in Kona (99-0048/N1224). Note changed resolution of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#196">196</a>
to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198">198</a>. Closed issues list split into "defects" and
"closed" documents. Changed the proposed resolution of issue
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> to NAD, and changed the wording of proposed resolution
of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>.
</li>
<li>R10:
pre-Kona updated. Added proposed resolutions <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a>. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a> to
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#195">195</a>. (99-0033/D1209, 14 Oct 99)
</li>
<li>R9:
pre-Kona mailing. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a> to
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#189">189</a>. Issues list split into separate "active" and
"closed" documents. (99-0030/N1206, 25 Aug 99)
</li>
<li>R8:
post-Dublin mailing. Updated to reflect LWG and full committee actions
in Dublin. (99-0016/N1193, 21 Apr 99)
</li>
<li>R7:
pre-Dublin updated: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#131">131</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#132">132</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#133">133</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#135">135</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#139">139</a> (31 Mar 99)
</li>
<li>R6:
pre-Dublin mailing. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>,
and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>. (99-0007/N1194, 22 Feb 99)
</li>
<li>R5:
update issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>; added issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#126">126</a>. Format revisions to prepare
for making list public. (30 Dec 98)
</li>
<li>R4:
post-Santa Cruz II updated: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#110">110</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#113">113</a> added, several
issues corrected. (22 Oct 98)
</li>
<li>R3:
post-Santa Cruz II: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#94">94</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a>
added, many issues updated to reflect LWG consensus (12 Oct 98)
</li>
<li>R2:
pre-Santa Cruz II: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#73">73</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#93">93</a> added,
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a> updated. (29 Sep 98)
</li>
<li>R1:
Correction to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#55">55</a> resolution, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a> code
format, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a> title. (17 Sep 98)
</li>
</ul>
<h2>Closed Issues</h2>
<hr>
<h3><a name="2"></a>2. Auto_ptr conversions effects incorrect</h3>
<p><b>Section:</b> D.9.1.3 [auto.ptr.conv] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nathan Myers <b>Date:</b> 1997-12-04</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Paragraph 1 in "Effects", says "Calls
p->release()" where it clearly must be "Calls
p.release()". (As it is, it seems to require using
auto_ptr<>::operator-> to refer to X::release, assuming that
exists.)</p>
<p><b>Proposed resolution:</b></p>
<p>Change 20.4.4.3 [meta.unary.prop] paragraph 1 Effects from
"Calls p->release()" to "Calls p.release()".</p>
<p><b>Rationale:</b></p>
<p>Not a defect: the proposed change is already found in the standard.
[Originally classified as a defect, later reclassified.]</p>
<hr>
<h3><a name="4"></a>4. Basic_string size_type and difference_type should be implementation defined</h3>
<p><b>Section:</b> 21.3 [basic.string] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Beman Dawes <b>Date:</b> 1997-11-16</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#basic.string">active issues</a> in [basic.string].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#basic.string">issues</a> in [basic.string].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In Morristown we changed the size_type and difference_type typedefs
for all the other containers to implementation defined with a
reference to 23.1 [container.requirements]. This should probably also have been
done for strings. </p>
<p><b>Rationale:</b></p>
<p>Not a defect. [Originally classified as a defect, later
reclassified.] basic_string, unlike the other standard library
template containers, is severely constrained by its use of
char_traits. Those types are dictated by the traits class, and are far
from implementation defined.</p>
<hr>
<h3><a name="6"></a>6. File position not an offset unimplementable</h3>
<p><b>Section:</b> 27.4.3 [fpos] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 1997-12-15</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#fpos">issues</a> in [fpos].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Table 88, in I/O, is too strict; it's unimplementable on systems
where a file position isn't just an offset. It also never says just
what fpos<> is really supposed to be. [Here's my summary, which
Jerry agrees is more or less accurate. "I think I now know what
the class really is, at this point: it's a magic cookie that
encapsulates an mbstate_t and a file position (possibly represented as
an fpos_t), it has syntactic support for pointer-like arithmetic, and
implementors are required to have real, not just syntactic, support
for arithmetic." This isn't standardese, of course.] </p>
<p><b>Rationale:</b></p>
<p>Not a defect. The LWG believes that the Standard is already clear,
and that the above summary is what the Standard in effect says.</p>
<hr>
<h3><a name="10"></a>10. Codecvt<>::do unclear</h3>
<p><b>Section:</b> 22.2.1.5 [locale.codecvt.byname] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 1998-01-14</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt.byname">issues</a> in [locale.codecvt.byname].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#19">19</a></p>
<p><b>Discussion:</b></p>
<p>Section 22.2.1.5.2 says that codecvt<>::do_in and do_out
should return the value noconv if "no conversion was
needed". However, I don't see anything anywhere that defines what
it means for a conversion to be needed or not needed. I can think of
several circumstances where one might plausibly think that a
conversion is not "needed", but I don't know which one is
intended here. </p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="12"></a>12. Way objects hold allocators unclear</h3>
<p><b>Section:</b> 20.1.2 [allocator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Angelika Langer <b>Date:</b> 1998-02-23</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#allocator.requirements">active issues</a> in [allocator.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#allocator.requirements">issues</a> in [allocator.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>I couldn't find a statement in the standard saying whether the allocator object held by
a container is held as a copy of the constructor argument or whether a pointer of
reference is maintained internal. There is an according statement for compare objects and
how they are maintained by the associative containers, but I couldn't find anything
regarding allocators. </p>
<p>Did I overlook it? Is it an open issue or known defect? Or is it deliberately left
unspecified? </p>
<p><b>Rationale:</b></p>
<p>Not a defect. The LWG believes that the Standard is already
clear. See 23.1 [container.requirements], paragraph 8.</p>
<hr>
<h3><a name="43"></a>43. Locale table correction</h3>
<p><b>Section:</b> 22.2.1.5 [locale.codecvt.byname] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Brendan Kehoe <b>Date:</b> 1998-06-01</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt.byname">issues</a> in [locale.codecvt.byname].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#33">33</a></p>
<p><b>Discussion:</b></p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="45"></a>45. Stringstreams read/write pointers initial position unclear</h3>
<p><b>Section:</b> 27.7.3 [ostringstream] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matthias Mueller <b>Date:</b> 1998-05-27</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In a comp.lang.c++.moderated Matthias Mueller wrote:</p>
<p>"We are not sure how to interpret the CD2 (see 27.2
[iostream.forward], 27.7.3.1 [ostringstream.cons], 27.7.1.1
[stringbuf.cons])
with respect to the question as to what the correct initial positions
of the write and read pointers of a stringstream should
be."</p>
<p>"Is it the same to output two strings or to initialize the stringstream with the
first and to output the second?"</p>
<p><i>[PJ Plauger, Bjarne Stroustrup, Randy Smithey, Sean Corfield, and
Jerry Schwarz have all offered opinions; see reflector messages
lib-6518, 6519, 6520, 6521, 6523, 6524.]</i></p>
<p><b>Rationale:</b></p>
<p>The LWG believes the Standard is correct as written. The behavior
of stringstreams is consistent with fstreams, and there is a
constructor which can be used to obtain the desired effect. This
behavior is known to be different from strstreams.</p>
<hr>
<h3><a name="58"></a>58. Extracting a char from a wide-oriented stream</h3>
<p><b>Section:</b> 27.6.1.2.3 [istream::extractors] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 1998-07-01</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream::extractors">issues</a> in [istream::extractors].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>27.6.1.2.3 has member functions for extraction of signed char and
unsigned char, both singly and as strings. However, it doesn't say
what it means to extract a <tt>char</tt> from a
<tt>basic_streambuf<charT, Traits></tt>. </p>
<p>basic_streambuf, after all, has no members to extract a char, so
basic_istream must somehow convert from charT to signed char or
unsigned char. The standard doesn't say how it is to perform that
conversion. </p>
<p><b>Rationale:</b></p>
<p>The Standard is correct as written. There is no such extractor and
this is the intent of the LWG.</p>
<hr>
<h3><a name="65"></a>65. Underspecification of strstreambuf::seekoff</h3>
<p><b>Section:</b> D.7.1.3 [depr.strstreambuf.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 1998-08-18</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#depr.strstreambuf.virtuals">issues</a> in [depr.strstreambuf.virtuals].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The standard says how this member function affects the current
stream position. (<tt>gptr</tt> or <tt>pptr</tt>) However, it does not
say how this member function affects the beginning and end of the
get/put area. </p>
<p>This is an issue when seekoff is used to position the get pointer
beyond the end of the current read area. (Which is legal. This is
implicit in the definition of <i>seekhigh</i> in D.7.1, paragraph 4.)
</p>
<p><b>Rationale:</b></p>
<p>The LWG agrees that seekoff() is underspecified, but does not wish
to invest effort in this deprecated feature.</p>
<hr>
<h3><a name="67"></a>67. Setw useless for strings</h3>
<p><b>Section:</b> 21.3.8.9 [string.io] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Steve Clamage <b>Date:</b> 1998-07-09</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string.io">issues</a> in [string.io].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#25">25</a></p>
<p><b>Discussion:</b></p>
<p>In a comp.std.c++ posting Michel Michaud wrote: What
should be output by: </p>
<pre> string text("Hello");
cout << '[' << setw(10) << right << text << ']';
</pre>
<p>Shouldn't it be:</p>
<pre> [ Hello]</pre>
<p>Another person replied: Actually, according to the FDIS, the width
of the field should be the minimum of width and the length of the
string, so the output shouldn't have any padding. I think that this is
a typo, however, and that what is wanted is the maximum of the
two. (As written, setw is useless for strings. If that had been the
intent, one wouldn't expect them to have mentioned using its value.)
</p>
<p>It's worth pointing out that this is a recent correction anyway;
IIRC, earlier versions of the draft forgot to mention formatting
parameters whatsoever.</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="72"></a>72. Do_convert phantom member function</h3>
<p><b>Section:</b> 22.2.1.4 [locale.codecvt] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Nathan Myers <b>Date:</b> 1998-08-24</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt">issues</a> in [locale.codecvt].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#24">24</a></p>
<p><b>Discussion:</b></p>
<p>In 22.2.1.4 [locale.codecvt] par 3, and in 22.2.1.4.2 [locale.codecvt.virtuals] par 8, a nonexistent member function
"do_convert" is mentioned. This member was replaced with
"do_in" and "do_out", the proper referents in the
contexts above.</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="73"></a>73. <tt>is_open</tt> should be const</h3>
<p><b>Section:</b> 27.8.1 [fstreams] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 1998-08-27</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#fstreams">issues</a> in [fstreams].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Classes <tt>basic_ifstream</tt>, <tt>basic_ofstream</tt>, and
<tt>basic_fstream</tt> all have a member function <tt>is_open</tt>. It
should be a <tt>const</tt> member function, since it does nothing but
call one of <tt>basic_filebuf</tt>'s const member functions. </p>
<p><b>Rationale:</b></p>
<p>Not a defect. This is a deliberate feature; const streams would be
meaningless.</p>
<hr>
<h3><a name="77"></a>77. Valarray operator[] const returning value</h3>
<p><b>Section:</b> 26.5.2.3 [valarray.access] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Levente Farkas <b>Date:</b> 1998-09-09</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#valarray.access">issues</a> in [valarray.access].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a></p>
<p><b>Discussion:</b></p>
<p>valarray:<br>
<br>
<tt>T operator[] (size_t) const;</tt><br>
<br>
why not <br>
<br>
<tt>const T& operator[] (size_t) const;</tt><br>
<br>
as in vector ???<br>
<br>
One can't copy even from a const valarray eg:<br>
<br>
<tt>memcpy(ptr, &v[0], v.size() * sizeof(double));<br>
</tt><br>
[I] find this bug in valarray is very difficult.</p>
<p><b>Rationale:</b></p>
<p>The LWG believes that the interface was deliberately designed that
way. That is what valarray was designed to do; that's where the
"value array" name comes from. LWG members further comment
that "we don't want valarray to be a full STL container."
26.5.2.3 [valarray.access] specifies properties that indicate "an
absence of aliasing" for non-constant arrays; this allows
optimizations, including special hardware optimizations, that are not
otherwise possible. </p>
<hr>
<h3><a name="81"></a>81. Wrong declaration of slice operations</h3>
<p><b>Section:</b> 26.5.5 [template.slice.array], 26.5.7 [template.gslice.array], 26.5.8 [template.mask.array], 26.5.9 [template.indirect.array] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.slice.array">issues</a> in [template.slice.array].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Isn't the definition of copy constructor and assignment operators wrong?
Instead of</p>
<pre> slice_array(const slice_array&);
slice_array& operator=(const slice_array&);</pre>
<p>IMHO they have to be</p>
<pre> slice_array(const slice_array<T>&);
slice_array& operator=(const slice_array<T>&);</pre>
<p>Same for gslice_array. </p>
<p><b>Rationale:</b></p>
<p>Not a defect. The Standard is correct as written. </p>
<hr>
<h3><a name="82"></a>82. Missing constant for set elements</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Paragraph 5 specifies:</p>
<blockquote><p>
For set and multiset the value type is the same as the key type. For
map and multimap it is equal to pair<const Key, T>.
</p></blockquote>
<p>Strictly speaking, this is not correct because for set and multiset
the value type is the same as the <b>constant</b> key type.</p>
<p><b>Rationale:</b></p>
<p>Not a defect. The Standard is correct as written; it uses a
different mechanism (const &) for <tt>set</tt> and
<tt>multiset</tt>. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> for a related
issue.</p>
<hr>
<h3><a name="84"></a>84. Ambiguity with string::insert()</h3>
<p><b>Section:</b> 21.3.5 [string.access] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>If I try</p>
<pre> s.insert(0,1,' ');</pre>
<p> I get an nasty ambiguity. It might be</p>
<pre> s.insert((size_type)0,(size_type)1,(charT)' ');</pre>
<p>which inserts 1 space character at position 0, or</p>
<pre> s.insert((char*)0,(size_type)1,(charT)' ')</pre>
<p>which inserts 1 space character at iterator/address 0 (bingo!), or</p>
<pre> s.insert((char*)0, (InputIterator)1, (InputIterator)' ')</pre>
<p>which normally inserts characters from iterator 1 to iterator '
'. But according to 23.1.1.9 (the "do the right thing" fix)
it is equivalent to the second. However, it is still ambiguous,
because of course I mean the first!</p>
<p><b>Rationale:</b></p>
<p>Not a defect. The LWG believes this is a "genetic
misfortune" inherent in the design of string and thus not a
defect in the Standard as such .</p>
<hr>
<h3><a name="85"></a>85. String char types</h3>
<p><b>Section:</b> 21 [strings] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#strings">issues</a> in [strings].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The standard seems not to require that charT is equivalent to
traits::char_type. So, what happens if charT is not equivalent to
traits::char_type?</p>
<p><b>Rationale:</b></p>
<p>There is already wording in 21.1 [char.traits] paragraph 3 that
requires them to be the same.</p>
<hr>
<h3><a name="87"></a>87. Error in description of string::compare()</h3>
<p><b>Section:</b> 21.3.6.8 [string::swap] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string::swap">issues</a> in [string::swap].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#5">5</a></p>
<p><b>Discussion:</b></p>
<p>The following compare() description is obviously a bug:</p>
<pre>int compare(size_type pos, size_type n1,
charT *s, size_type n2 = npos) const;
</pre>
<p>because without passing n2 it should compare up to the end of the
string instead of comparing npos characters (which throws an
exception) </p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="88"></a>88. Inconsistency between string::insert() and string::append()</h3>
<p><b>Section:</b> 21.3.6.4 [string::insert], 21.3.6.2 [string::append] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string::insert">issues</a> in [string::insert].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Why does </p>
<pre> template<class InputIterator>
basic_string& append(InputIterator first, InputIterator last);</pre>
<p>return a string, while</p>
<pre> template<class InputIterator>
void insert(iterator p, InputIterator first, InputIterator last);</pre>
<p>returns nothing ?</p>
<p><b>Rationale:</b></p>
<p>The LWG believes this stylistic inconsistency is not sufficiently
serious to constitute a defect.</p>
<hr>
<h3><a name="89"></a>89. Missing throw specification for string::insert() and string::replace()</h3>
<p><b>Section:</b> 21.3.6.4 [string::insert], 21.3.6.6 [string::replace] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string::insert">issues</a> in [string::insert].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a></p>
<p><b>Discussion:</b></p>
<p>All insert() and replace() members for strings with an iterator as
first argument lack a throw specification. The throw
specification should probably be: length_error if size exceeds
maximum. </p>
<p><b>Rationale:</b></p>
<p>Considered a duplicate because it will be solved by the resolution
of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>.</p>
<hr>
<h3><a name="93"></a>93. Incomplete Valarray Subset Definitions</h3>
<p><b>Section:</b> 26.5 [numarray] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1998-09-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#numarray">issues</a> in [numarray].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>You can easily create subsets, but you can't easily combine them
with other subsets. Unfortunately, you almost always needs an
explicit type conversion to valarray. This is because the standard
does not specify that valarray subsets provide the same operations as
valarrays. </p>
<p>For example, to multiply two subsets and assign the result to a third subset, you can't
write the following:</p>
<pre>va[slice(0,4,3)] = va[slice(1,4,3)] * va[slice(2,4,3)];</pre>
<p>Instead, you have to code as follows:</p>
<pre>va[slice(0,4,3)] = static_cast<valarray<double> >(va[slice(1,4,3)]) *
static_cast<valarray<double> >(va[slice(2,4,3)]);</pre>
<p>This is tedious and error-prone. Even worse, it costs performance because each cast
creates a temporary objects, which could be avoided without the cast. </p>
<p><b>Proposed resolution:</b></p>
<p>Extend all valarray subset types so that they offer all valarray operations.</p>
<p><b>Rationale:</b></p>
<p>This is not a defect in the Standard; it is a request for an extension.</p>
<hr>
<h3><a name="94"></a>94. May library implementors add template parameters to Standard Library classes?</h3>
<p><b>Section:</b> 17.4.4 [conforming] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 1998-01-22</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Is it a permitted extension for library implementors to add template parameters to
standard library classes, provided that those extra parameters have defaults? For example,
instead of defining <tt>template <class T, class Alloc = allocator<T> > class
vector;</tt> defining it as <tt>template <class T, class Alloc = allocator<T>,
int N = 1> class vector;</tt> </p>
<p>The standard may well already allow this (I can't think of any way that this extension
could break a conforming program, considering that users are not permitted to
forward-declare standard library components), but it ought to be explicitly permitted or
forbidden. </p>
<p>comment from Steve Cleary via comp.std.c++:</p>
<blockquote>
<p>I disagree [with the proposed resolution] for the following reason:
consider user library code with template template parameters. For
example, a user library object may be templated on the type of
underlying sequence storage to use (deque/list/vector), since these
classes all take the same number and type of template parameters; this
would allow the user to determine the performance tradeoffs of the
user library object. A similar example is a user library object
templated on the type of underlying set storage (set/multiset) or map
storage (map/multimap), which would allow users to change (within
reason) the semantic meanings of operations on that object.</p>
<p>I think that additional template parameters should be forbidden in
the Standard classes. Library writers don't lose any expressive power,
and can still offer extensions because additional template parameters
may be provided by a non-Standard implementation class:</p>
<pre>
template <class T, class Allocator = allocator<T>, int N = 1>
class __vector
{ ... };
template <class T, class Allocator = allocator<T> >
class vector: public __vector<T, Allocator>
{ ... };
</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Add a new subclause [presumably 17.4.4.9] following 17.4.4.8 [res.on.exception.handling]:</p>
<blockquote>
<p>17.4.4.9 Template Parameters</p> <p>A specialization of a
template class described in the C++ Standard Library behaves the
same as if the implementation declares no additional template
parameters.</p> <p>Footnote: Additional template parameters with
default values are thus permitted.</p>
</blockquote>
<p>Add "template parameters" to the list of subclauses at
the end of 17.4.4 [conforming] paragraph 1.</p>
<p><i>[Kona: The LWG agreed the standard needs clarification. After
discussion with John Spicer, it seems added template parameters can be
detected by a program using template-template parameters. A straw vote
- "should implementors be allowed to add template
parameters?" found no consensus ; 5 - yes, 7 - no.]</i></p>
<p><b>Rationale:</b></p>
<p>
There is no ambiguity; the standard is clear as written. Library
implementors are not permitted to add template parameters to standard
library classes. This does not fall under the "as if" rule,
so it would be permitted only if the standard gave explicit license
for implementors to do this. This would require a change in the
standard.
</p>
<p>
The LWG decided against making this change, because it would break
user code involving template template parameters or specializations
of standard library class templates.
</p>
<hr>
<h3><a name="95"></a>95. Members added by the implementation</h3>
<p><b>Section:</b> 17.4.4.4 [member.functions] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In 17.3.4.4/2 vs 17.3.4.7/0 there is a hole; an implementation could add virtual
members a base class and break user derived classes.</p>
<p>Example: </p>
<blockquote>
<pre>// implementation code:
struct _Base { // _Base is in the implementer namespace
virtual void foo ();
};
class vector : _Base // deriving from a class is allowed
{ ... };
// user code:
class vector_checking : public vector
{
void foo (); // don't want to override _Base::foo () as the
// user doesn't know about _Base::foo ()
};</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Clarify the wording to make the example illegal.</p>
<p><b>Rationale:</b></p>
<p>This is not a defect in the Standard. The example is already
illegal. See 17.4.4.4 [member.functions] paragraph 2.</p>
<hr>
<h3><a name="97"></a>97. Insert inconsistent definition</h3>
<p><b>Section:</b> 23 [containers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#containers">issues</a> in [containers].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p><tt>insert(iterator, const value_type&)</tt> is defined both on
sequences and on set, with unrelated semantics: insert here (in
sequences), and insert with hint (in associative containers). They
should have different names (B.S. says: do not abuse overloading).</p>
<p><b>Rationale:</b></p>
<p>This is not a defect in the Standard. It is a genetic misfortune of
the design, for better or for worse.</p>
<hr>
<h3><a name="99"></a>99. Reverse_iterator comparisons completely wrong</h3>
<p><b>Section:</b> 24.4.1.3.13 [reverse.iter.op==] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The <, >, <=, >= comparison operator are wrong: they
return the opposite of what they should.</p>
<p>Note: same problem in CD2, these were not even defined in CD1. SGI
STL code is correct; this problem is known since the Morristown
meeting but there it was too late</p>
<p><b>Rationale:</b></p>
<p>This is not a defect in the Standard. A careful reading shows the Standard is correct
as written. A review of several implementations show that they implement
exactly what the Standard says.</p>
<hr>
<h3><a name="100"></a>100. Insert iterators/ostream_iterators overconstrained</h3>
<p><b>Section:</b> 24.4.2 [insert.iterators], 24.5.4 [ostreambuf.iterator] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Overspecified For an insert iterator it, the expression *it is
required to return a reference to it. This is a simple possible
implementation, but as the SGI STL documentation says, not the only
one, and the user should not assume that this is the case.</p>
<p><b>Rationale:</b></p>
<p>The LWG believes this causes no harm and is not a defect in the
standard. The only example anyone could come up with caused some
incorrect code to work, rather than the other way around.</p>
<hr>
<h3><a name="101"></a>101. No way to free storage for vector and deque</h3>
<p><b>Section:</b> 23.2.5 [vector], 23.2.1 [array] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#vector">issues</a> in [vector].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Reserve can not free storage, unlike string::reserve</p>
<p><b>Rationale:</b></p>
<p>This is not a defect in the Standard. The LWG has considered this
issue in the past and sees no need to change the Standard. Deque has
no reserve() member function. For vector, shrink-to-fit can be
expressed in a single line of code (where <tt>v</tt> is
<tt>vector<T></tt>):
</p>
<blockquote>
<p><tt>vector<T>(v).swap(v); // shrink-to-fit v</tt></p>
</blockquote>
<hr>
<h3><a name="102"></a>102. Bug in insert range in associative containers</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a></p>
<p><b>Discussion:</b></p>
<p>Table 69 of Containers say that a.insert(i,j) is linear if [i, j) is ordered. It seems
impossible to implement, as it means that if [i, j) = [x], insert in an associative
container is O(1)!</p>
<p><b>Proposed resolution:</b></p>
<p>N+log (size()) if [i,j) is sorted according to value_comp()</p>
<p><b>Rationale:</b></p>
<p>Subsumed by issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a>.</p>
<hr>
<h3><a name="104"></a>104. Description of basic_string::operator[] is unclear</h3>
<p><b>Section:</b> 21.3.4 [string.capacity] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string.capacity">issues</a> in [string.capacity].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>It is not clear that undefined behavior applies when pos == size ()
for the non const version.</p>
<p><b>Proposed resolution:</b></p>
<p>Rewrite as: Otherwise, if pos > size () or pos == size () and
the non-const version is used, then the behavior is undefined.</p>
<p><b>Rationale:</b></p>
<p>The Standard is correct. The proposed resolution already appears in
the Standard.</p>
<hr>
<h3><a name="105"></a>105. fstream ctors argument types desired</h3>
<p><b>Section:</b> 27.8 [file.streams] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>fstream ctors take a const char* instead of string.<br>
fstream ctors can't take wchar_t</p>
<p>An extension to add a const wchar_t* to fstream would make the
implementation non conforming.</p>
<p><b>Rationale:</b></p>
<p>This is not a defect in the Standard. It might be an
interesting extension for the next Standard. </p>
<hr>
<h3><a name="107"></a>107. Valarray constructor is strange</h3>
<p><b>Section:</b> 26.5.2 [template.valarray] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> AFNOR <b>Date:</b> 1998-10-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.valarray">issues</a> in [template.valarray].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The order of the arguments is (elem, size) instead of the normal
(size, elem) in the rest of the library. Since elem often has an
integral or floating point type, both types are convertible to each
other and reversing them leads to a well formed program.</p>
<p><b>Proposed resolution:</b></p>
<p>Inverting the arguments could silently break programs. Introduce
the two signatures (const T&, size_t) and (size_t, const T&),
but make the one we do not want private so errors result in a
diagnosed access violation. This technique can also be applied to STL
containers.</p>
<p><b>Rationale:</b></p>
<p>The LWG believes that while the order of arguments is unfortunate,
it does not constitute a defect in the standard. The LWG believes that
the proposed solution will not work for valarray<size_t> and
perhaps other cases.</p>
<hr>
<h3><a name="111"></a>111. istreambuf_iterator::equal overspecified, inefficient</h3>
<p><b>Section:</b> 24.5.3.5 [istreambuf.iterator::equal] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Nathan Myers <b>Date:</b> 1998-10-15</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>The member istreambuf_iterator<>::equal is specified to be
unnecessarily inefficient. While this does not affect the efficiency
of conforming implementations of iostreams, because they can
"reach into" the iterators and bypass this function, it does
affect users who use istreambuf_iterators. </p>
<p>The inefficiency results from a too-scrupulous definition, which
requires a "true" result if neither iterator is at eof. In
practice these iterators can only usefully be compared with the
"eof" value, so the extra test implied provides no benefit,
but slows down users' code. </p>
<p>The solution is to weaken the requirement on the function to return
true only if both iterators are at eof. </p>
<p><b>Proposed resolution:</b></p>
<p>Replace 24.5.3.5 [istreambuf.iterator::equal],
paragraph 1, </p>
<blockquote>
<p>-1- Returns: true if and only if both iterators are at end-of-stream, or neither is at
end-of-stream, regardless of what streambuf object they use. </p>
</blockquote>
<p>with</p>
<blockquote>
<p>-1- Returns: true if and only if both iterators are at
end-of-stream, regardless of what streambuf object they use. </p>
</blockquote>
<p><b>Rationale:</b></p>
<p>It is not clear that this is a genuine defect. Additionally, the
LWG was reluctant to make a change that would result in
operator== not being a equivalence relation. One consequence of
this change is that an algorithm that's passed the range [i, i)
would no longer treat it as an empty range.</p>
<hr>
<h3><a name="113"></a>113. Missing/extra iostream sync semantics</h3>
<p><b>Section:</b> 27.6.1.1 [istream], 27.6.1.3 [istream.unformatted] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Steve Clamage <b>Date:</b> 1998-10-13</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream">issues</a> in [istream].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In 27.6.1.1, class basic_istream has a member function sync, described in 27.6.1.3,
paragraph 36. </p>
<p>Following the chain of definitions, I find that the various sync functions have defined
semantics for output streams, but no semantics for input streams. On the other hand,
basic_ostream has no sync function. </p>
<p>The sync function should at minimum be added to basic_ostream, for internal
consistency. </p>
<p>A larger question is whether sync should have assigned semantics for input streams. </p>
<p>Classic iostreams said streambuf::sync flushes pending output and attempts to return
unread input characters to the source. It is a protected member function. The filebuf
version (which is public) has that behavior (it backs up the read pointer). Class
strstreambuf does not override streambuf::sync, and so sync can't be called on a
strstream. </p>
<p>If we can add corresponding semantics to the various sync functions, we should. If not,
we should remove sync from basic_istream.</p>
<p><b>Rationale:</b></p>
<p>A sync function is not needed in basic_ostream because the flush function provides the
desired functionality.</p>
<p>As for the other points, the LWG finds the standard correct as written.</p>
<hr>
<h3><a name="116"></a>116. bitset cannot be constructed with a const char*</h3>
<p><b>Section:</b> 23.3.5 [template.bitset] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 1998-11-06</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#template.bitset">active issues</a> in [template.bitset].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.bitset">issues</a> in [template.bitset].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>The following code does not compile with the EDG compiler:</p>
<blockquote>
<pre>#include <bitset>
using namespace std;
bitset<32> b("111111111");</pre>
</blockquote>
<p>If you cast the ctor argument to a string, i.e.:</p>
<blockquote>
<pre>bitset<32> b(string("111111111"));</pre>
</blockquote>
<p>then it will compile. The reason is that bitset has the following templatized
constructor:</p>
<blockquote>
<pre>template <class charT, class traits, class Allocator>
explicit bitset (const basic_string<charT, traits, Allocator>& str, ...);</pre>
</blockquote>
<p>According to the compiler vendor, Steve Adamcyk at EDG, the user
cannot pass this template constructor a <tt>const char*</tt> and
expect a conversion to <tt>basic_string</tt>. The reason is
"When you have a template constructor, it can get used in
contexts where type deduction can be done. Type deduction basically
comes up with exact matches, not ones involving conversions."
</p>
<p>I don't think the intention when this constructor became
templatized was for construction from a <tt>const char*</tt> to no
longer work.</p>
<p><b>Proposed resolution:</b></p>
<p>Add to 23.3.5 [template.bitset] a bitset constructor declaration</p>
<blockquote>
<pre>explicit bitset(const char*);</pre>
</blockquote>
<p>and in Section 23.3.5.1 [bitset.cons] add:</p>
<blockquote>
<pre>explicit bitset(const char* str);</pre>
<p>Effects: <br>
Calls <tt>bitset((string) str, 0, string::npos);</tt></p>
</blockquote>
<p><b>Rationale:</b></p>
<p>Although the problem is real, the standard is designed that way so
it is not a defect. Education is the immediate workaround. A future
standard may wish to consider the Proposed Resolution as an
extension.</p>
<hr>
<h3><a name="121"></a>121. Detailed definition for ctype<wchar_t> specialization</h3>
<p><b>Section:</b> 22.1.1.1.1 [locale.category] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 1998-12-15</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.category">issues</a> in [locale.category].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Section 22.1.1.1.1 has the following listed in Table 51: ctype<char> ,
ctype<wchar_t>. </p>
<p>Also Section 22.2.1.1 [locale.ctype] says: </p>
<blockquote>
<p>The instantiations required in Table 51 (22.1.1.1.1) namely ctype<char> and
ctype<wchar_t> , implement character classing appropriate to the implementation's
native character set. </p>
</blockquote>
<p>However, Section 22.2.1.3 [facet.ctype.special]
only has a detailed description of the ctype<char> specialization, not the
ctype<wchar_t> specialization. </p>
<p><b>Proposed resolution:</b></p>
<p>Add the ctype<wchar_t> detailed class description to Section
22.2.1.3 [facet.ctype.special]. </p>
<p><b>Rationale:</b></p>
<p>Specialization for wchar_t is not needed since the default is acceptable.</p>
<hr>
<h3><a name="128"></a>128. Need open_mode() function for file stream, string streams, file buffers, and string buffers</h3>
<p><b>Section:</b> 27.7 [string.streams], 27.8 [file.streams] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Angelika Langer <b>Date:</b> 1999-02-22</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string.streams">issues</a> in [string.streams].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>The following question came from Thorsten Herlemann:</p>
<blockquote>
<p>You can set a mode when constructing or opening a file-stream or
filebuf, e.g. ios::in, ios::out, ios::binary, ... But how can I get
that mode later on, e.g. in my own operator << or operator
>> or when I want to check whether a file-stream or
file-buffer object passed as parameter is opened for input or output
or binary? Is there no possibility? Is this a design-error in the
standard C++ library? </p>
</blockquote>
<p>It is indeed impossible to find out what a stream's or stream
buffer's open mode is, and without that knowledge you don't know
how certain operations behave. Just think of the append mode. </p>
<p>Both streams and stream buffers should have a <tt>mode()</tt> function that returns the
current open mode setting. </p>
<p><b>Proposed resolution:</b></p>
<p>For stream buffers, add a function to the base class as a non-virtual function
qualified as const to 27.5.2 [streambuf]:</p>
<p> <tt>openmode mode() const</tt>;</p>
<p><b> Returns</b> the current open mode.</p>
<p>With streams, I'm not sure what to suggest. In principle, the mode
could already be returned by <tt>ios_base</tt>, but the mode is only
initialized for file and string stream objects, unless I'm overlooking
anything. For this reason it should be added to the most derived
stream classes. Alternatively, it could be added to <tt>basic_ios</tt>
and would be default initialized in <tt>basic_ios<>::init()</tt>.</p>
<p><b>Rationale:</b></p>
<p>This might be an interesting extension for some future, but it is
not a defect in the current standard. The Proposed Resolution is
retained for future reference.</p>
<hr>
<h3><a name="131"></a>131. list::splice throws nothing</h3>
<p><b>Section:</b> 23.2.3.4 [list.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Howard Hinnant <b>Date:</b> 1999-03-06</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#list.ops">issues</a> in [list.ops].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>What happens if a splice operation causes the size() of a list to grow
beyond max_size()?</p>
<p><b>Rationale:</b></p>
<p>Size() cannot grow beyond max_size(). </p>
<hr>
<h3><a name="135"></a>135. basic_iostream doubly initialized</h3>
<p><b>Section:</b> 27.6.1.5.1 [iostream.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Howard Hinnant <b>Date:</b> 1999-03-06</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>-1- Effects Constructs an object of class basic_iostream, assigning
initial values to the base classes by calling
basic_istream<charT,traits>(sb) (lib.istream) and
basic_ostream<charT,traits>(sb) (lib.ostream)</p>
<p>The called for basic_istream and basic_ostream constructors call
init(sb). This means that the basic_iostream's virtual base class is
initialized twice.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.6.1.5.1, paragraph 1 to:</p>
<p>-1- Effects Constructs an object of class basic_iostream, assigning
initial values to the base classes by calling
basic_istream<charT,traits>(sb) (lib.istream).</p>
<p><b>Rationale:</b></p>
<p>The LWG agreed that the <tt> init()</tt> function is called
twice, but said that this is harmless and so not a defect in the
standard.</p>
<hr>
<h3><a name="138"></a>138. Class ctype_byname<char> redundant and misleading</h3>
<p><b>Section:</b> 22.2.1.4 [locale.codecvt] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Angelika Langer <b>Date:</b> 1999-03-18</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt">issues</a> in [locale.codecvt].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>Section 22.2.1.4 [locale.codecvt] specifies that
ctype_byname<char> must be a specialization of the ctype_byname
template.</p>
<p>It is common practice in the standard that specializations of class templates are only
mentioned where the interface of the specialization deviates from the interface of the
template that it is a specialization of. Otherwise, the fact whether or not a required
instantiation is an actual instantiation or a specialization is left open as an
implementation detail. </p>
<p>Clause 22.2.1.4 deviates from that practice and for that reason is misleading. The
fact, that ctype_byname<char> is specified as a specialization suggests that there
must be something "special" about it, but it has the exact same interface as the
ctype_byname template. Clause 22.2.1.4 does not have any explanatory value, is at best
redundant, at worst misleading - unless I am missing anything. </p>
<p>Naturally, an implementation will most likely implement ctype_byname<char> as a
specialization, because the base class ctype<char> is a specialization with an
interface different from the ctype template, but that's an implementation detail and need
not be mentioned in the standard. </p>
<p><b>Rationale:</b></p>
<p> The standard as written is mildly misleading, but the correct fix
is to deal with the underlying problem in the ctype_byname base class,
not in the specialization. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a>.</p>
<hr>
<h3><a name="140"></a>140. map<Key, T>::value_type does not satisfy the assignable requirement</h3>
<p><b>Section:</b> 23.3.1 [map] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Mark Mitchell <b>Date:</b> 1999-04-14</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#map">issues</a> in [map].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<blockquote>
<p>23.1 [container.requirements]<br>
<br>
expression return type
pre/post-condition<br>
------------- -----------
-------------------<br>
X::value_type T
T is assignable<br>
<br>
23.3.1 [map]<br>
<br>
A map satisfies all the requirements of a container.<br>
<br>
For a map<Key, T> ... the value_type is pair<const Key, T>.</p>
</blockquote>
<p>There's a contradiction here. In particular, `pair<const Key,
T>' is not assignable; the `const Key' cannot be assigned
to. So, map<Key, T>::value_type does not satisfy the
assignable requirement imposed by a container.</p>
<p><i>[See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> for the slightly related issue of
modification of set keys.]</i></p>
<p><b>Rationale:</b></p>
<p>The LWG believes that the standard is inconsistent, but that this
is a design problem rather than a strict defect. May wish to
reconsider for the next standard.</p>
<hr>
<h3><a name="143"></a>143. C .h header wording unclear</h3>
<p><b>Section:</b> D.5 [depr.c.headers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Christophe de Dinechin <b>Date:</b> 1999-05-04</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>[depr.c.headers] paragraph 2 reads:</p>
<blockquote>
<p>Each C header, whose name has the form name.h, behaves as if each
name placed in the Standard library namespace by the corresponding
cname header is also placed within the namespace scope of the
namespace std and is followed by an explicit using-declaration
(_namespace.udecl_)</p>
</blockquote>
<p>I think it should mention the global name space somewhere...
Currently, it indicates that name placed in std is also placed in
std...</p>
<p>I don't know what is the correct wording. For instance, if struct
tm is defined in time.h, ctime declares std::tm. However, the current
wording seems ambiguous regarding which of the following would occur
for use of both ctime and time.h:</p>
<blockquote>
<pre>// version 1:
namespace std {
struct tm { ... };
}
using std::tm;
// version 2:
struct tm { ... };
namespace std {
using ::tm;
}
// version 3:
struct tm { ... };
namespace std {
struct tm { ... };
}</pre>
</blockquote>
<p>I think version 1 is intended.</p>
<p><i>[Kona: The LWG agreed that the wording is not clear. It also
agreed that version 1 is intended, version 2 is not equivalent to
version 1, and version 3 is clearly not intended. The example below
was constructed by Nathan Myers to illustrate why version 2 is not
equivalent to version 1.</i></p>
<p><i>Although not equivalent, the LWG is unsure if (2) is enough of
a problem to be prohibited. Points discussed in favor of allowing
(2):</i></p>
<blockquote>
<ul>
<li><i>It may be a convenience to implementors.</i></li>
<li><i>The only cases that fail are structs, of which the C library
contains only a few.</i></li>
</ul>
</blockquote>
<p><i>]</i></p>
<p><b>Example:</b></p>
<blockquote>
<pre>#include <time.h>
#include <utility>
int main() {
std::tm * t;
make_pair( t, t ); // okay with version 1 due to Koenig lookup
// fails with version 2; make_pair not found
return 0;
}</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Replace D.5 [depr.c.headers] paragraph 2 with:</p>
<blockquote>
<p> Each C header, whose name has the form name.h, behaves as if each
name placed in the Standard library namespace by the corresponding
cname header is also placed within the namespace scope of the
namespace std by name.h and is followed by an explicit
using-declaration (_namespace.udecl_) in global scope.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p> The current wording in the standard is the result of a difficult
compromise that averted delay of the standard. Based on discussions
in Tokyo it is clear that there is no still no consensus on stricter
wording, so the issue has been closed. It is suggested that users not
write code that depends on Koenig lookup of C library functions.</p>
<hr>
<h3><a name="145"></a>145. adjustfield lacks default value</h3>
<p><b>Section:</b> 27.4.4.1 [basic.ios.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Angelika Langer <b>Date:</b> 1999-05-12</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#basic.ios.cons">issues</a> in [basic.ios.cons].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>There is no initial value for the adjustfield defined, although
many people believe that the default adjustment were right. This is a
common misunderstanding. The standard only defines that, if no
adjustment is specified, all the predefined inserters must add fill
characters before the actual value, which is "as if" the
right flag were set. The flag itself need not be set.</p>
<p>When you implement a user-defined inserter you cannot rely on right
being the default setting for the adjustfield. Instead, you must be
prepared to find none of the flags set and must keep in mind that in
this case you should make your inserter behave "as if" the
right flag were set. This is surprising to many people and complicates
matters more than necessary.</p>
<p>Unless there is a good reason why the adjustfield should not be
initialized I would suggest to give it the default value that
everybody expects anyway.</p>
<p><b>Rationale:</b></p>
<p>This is not a defect. It is deliberate that the default is no bits
set. Consider Arabic or Hebrew, for example. See 22.2.2.2.2 [facet.num.put.virtuals] paragraph 19, Table 61 - Fill padding.</p>
<hr>
<h3><a name="149"></a>149. Insert should return iterator to first element inserted</h3>
<p><b>Section:</b> 23.1.1 [sequence.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Andrew Koenig <b>Date:</b> 1999-06-28</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#sequence.reqmts">issues</a> in [sequence.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>Suppose that c and c1 are sequential containers and i is an
iterator that refers to an element of c. Then I can insert a copy of
c1's elements into c ahead of element i by executing </p>
<blockquote>
<pre>c.insert(i, c1.begin(), c1.end());</pre>
</blockquote>
<p>If c is a vector, it is fairly easy for me to find out where the
newly inserted elements are, even though i is now invalid: </p>
<blockquote>
<pre>size_t i_loc = i - c.begin();
c.insert(i, c1.begin(), c1.end());</pre>
</blockquote>
<p>and now the first inserted element is at c.begin()+i_loc and one
past the last is at c.begin()+i_loc+c1.size().<br>
<br>
But what if c is a list? I can still find the location of one past the
last inserted element, because i is still valid. To find the location
of the first inserted element, though, I must execute something like </p>
<blockquote>
<pre>for (size_t n = c1.size(); n; --n)
--i;</pre>
</blockquote>
<p>because i is now no longer a random-access iterator.<br>
<br>
Alternatively, I might write something like </p>
<blockquote>
<pre>bool first = i == c.begin();
list<T>::iterator j = i;
if (!first) --j;
c.insert(i, c1.begin(), c1.end());
if (first)
j = c.begin();
else
++j;</pre>
</blockquote>
<p>which, although wretched, requires less overhead.<br>
<br>
But I think the right solution is to change the definition of insert
so that instead of returning void, it returns an iterator that refers
to the first element inserted, if any, and otherwise is a copy of its
first argument. </p>
<p><b>Rationale:</b></p>
<p>The LWG believes this was an intentional design decision and so is
not a defect. It may be worth revisiting for the next standard.</p>
<hr>
<h3><a name="157"></a>157. Meaningless error handling for <tt>pword()</tt> and <tt>iword()</tt></h3>
<p><b>Section:</b> 27.4.2.5 [ios.base.storage] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dietmar Kühl <b>Date:</b> 1999-07-20</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ios.base.storage">issues</a> in [ios.base.storage].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#41">41</a></p>
<p><b>Discussion:</b></p>
<p>According to paragraphs 2 and 4 of 27.4.2.5 [ios.base.storage], the
functions <tt>iword()</tt> and <tt>pword()</tt> "set the
<tt>badbit</tt> (which might throw an exception)" on
failure. ... but what does it mean for <tt>ios_base</tt> to set the
<tt>badbit</tt>? The state facilities of the IOStream library are
defined in <tt>basic_ios</tt>, a derived class! It would be possible
to attempt a down cast but then it would be necessary to know the
character type used...</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="162"></a>162. Really "formatted input functions"?</h3>
<p><b>Section:</b> 27.6.1.2.3 [istream::extractors] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dietmar Kühl <b>Date:</b> 1999-07-20</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream::extractors">issues</a> in [istream::extractors].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a></p>
<p><b>Discussion:</b></p>
<p>It appears to be somewhat nonsensical to consider the functions
defined in the paragraphs 1 to 5 to be "Formatted input
function" but since these functions are defined in a section
labeled "Formatted input functions" it is unclear to me
whether these operators are considered formatted input functions which
have to conform to the "common requirements" from 27.6.1.2.1
[istream.formatted.reqmts]: If this is the case, all manipulators, not
just
<tt>ws</tt>, would skip whitespace unless <tt>noskipws</tt> is set
(... but setting <tt>noskipws</tt> using the manipulator syntax would
also skip whitespace :-)</p>
<p>See also issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#166">166</a> for the same problem in formatted
output</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="163"></a>163. Return of <tt>gcount()</tt> after a call to <tt>gcount</tt></h3>
<p><b>Section:</b> 27.6.1.3 [istream.unformatted] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dietmar Kühl <b>Date:</b> 1999-07-20</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream.unformatted">issues</a> in [istream.unformatted].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a></p>
<p><b>Discussion:</b></p>
<p>It is not clear which functions are to be considered unformatted
input functions. As written, it seems that all functions in 27.6.1.3
[istream.unformatted] are unformatted input functions. However, it does
not
really make much sense to construct a sentry object for
<tt>gcount()</tt>, <tt>sync()</tt>, ... Also it is unclear what
happens to the <tt>gcount()</tt> if eg. <tt>gcount()</tt>,
<tt>putback()</tt>, <tt>unget()</tt>, or <tt>sync()</tt> is called:
These functions don't extract characters, some of them even
"unextract" a character. Should this still be reflected in
<tt>gcount()</tt>? Of course, it could be read as if after a call to
<tt>gcount()</tt> <tt>gcount()</tt> return <tt>0</tt> (the last
unformatted input function, <tt>gcount()</tt>, didn't extract any
character) and after a call to <tt>putback()</tt> <tt>gcount()</tt>
returns <tt>-1</tt> (the last unformatted input function
<tt>putback()</tt> did "extract" back into the
stream). Correspondingly for <tt>unget()</tt>. Is this what is
intended? If so, this should be clarified. Otherwise, a corresponding
clarification should be used.</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="166"></a>166. Really "formatted output functions"?</h3>
<p><b>Section:</b> 27.6.2.6.3 [ostream.inserters] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dietmar Kühl <b>Date:</b> 1999-07-20</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a></p>
<p><b>Discussion:</b></p>
<p>From 27.6.2.6.1 [ostream.formatted.reqmts] it appears that all the functions
defined in 27.6.2.6.3 [ostream.inserters] have to construct a
<tt>sentry</tt> object. Is this really intended?</p>
<p>This is basically the same problem as issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#162">162</a> but
for output instead of input.</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="177"></a>177. Complex operators cannot be explicitly instantiated</h3>
<p><b>Section:</b> 26.3.6 [complex.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 1999-07-02</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#complex.ops">issues</a> in [complex.ops].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>A user who tries to explicitly instantiate a complex non-member operator will
get compilation errors. Below is a simplified example of the reason why. The
problem is that iterator_traits cannot be instantiated on a non-pointer type
like float, yet when the compiler is trying to decide which operator+ needs to
be instantiated it must instantiate the declaration to figure out the first
argument type of a reverse_iterator operator.</p>
<pre>namespace std {
template <class Iterator>
struct iterator_traits
{
typedef typename Iterator::value_type value_type;
};
template <class T> class reverse_iterator;
// reverse_iterator operator+
template <class T>
reverse_iterator<T> operator+
(typename iterator_traits<T>::difference_type, const reverse_iterator<T>&);
template <class T> struct complex {};
// complex operator +
template <class T>
complex<T> operator+ (const T& lhs, const complex<T>& rhs)
{ return complex<T>();}
}
// request for explicit instantiation
template std::complex<float> std::operator+<float>(const float&,
const std::complex<float>&);</pre>
<p>See also c++-stdlib reflector messages: lib-6814, 6815, 6816.</p>
<p><b>Rationale:</b></p>
<p>Implementors can make minor changes and the example will
work. Users are not affected in any case.</p> <p>According to John
Spicer, It is possible to explicitly instantiate these operators using
different syntax: change "std::operator+<float>" to
"std::operator+".</p>
<p>The proposed resolution of issue 120 is that users will not be able
to explicitly instantiate standard library templates. If that
resolution is accepted then library implementors will be the only ones
that will be affected by this problem, and they must use the indicated
syntax.</p>
<hr>
<h3><a name="178"></a>178. Should clog and cerr initially be tied to cout?</h3>
<p><b>Section:</b> 27.3.1 [narrow.stream.objects] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 1999-07-02</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#narrow.stream.objects">issues</a> in [narrow.stream.objects].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Section 27.3.1 says "After the object cerr is initialized,
cerr.flags() & unitbuf is nonzero. Its state is otherwise the same as
required for ios_base::init (lib.basic.ios.cons). It doesn't say
anything about the the state of clog. So this means that calling
cerr.tie() and clog.tie() should return 0 (see Table 89 for
ios_base::init effects).
</p>
<p>
Neither of the popular standard library implementations
that I tried does this, they both tie cerr and clog
to &cout. I would think that would be what users expect.
</p>
<p><b>Rationale:</b></p>
<p>The standard is clear as written.</p>
<p>27.3.1/5 says that "After the object cerr is initialized, cerr.flags()
& unitbuf is nonzero. Its state is otherwise the same as required for
ios_base::init (27.4.4.1)." Table 89 in 27.4.4.1, which gives the
postconditions of basic_ios::init(), says that tie() is 0. (Other issues correct
ios_base::init to basic_ios::init().)</p>
<hr>
<h3><a name="180"></a>180. Container member iterator arguments constness has unintended consequences</h3>
<p><b>Section:</b> 23 [containers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Dave Abrahams <b>Date:</b> 1999-07-01</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#containers">issues</a> in [containers].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>It is the constness of the container which should control whether
it can be modified through a member function such as erase(), not the
constness of the iterators. The iterators only serve to give
positioning information.</p>
<p>Here's a simple and typical example problem which is currently very
difficult or impossible to solve without the change proposed
below.</p>
<p>Wrap a standard container C in a class W which allows clients to
find and read (but not modify) a subrange of (C.begin(), C.end()]. The
only modification clients are allowed to make to elements in this
subrange is to erase them from C through the use of a member function
of W.</p>
<p><b>Proposed resolution:</b></p>
<p>Change all non-const iterator parameters of standard library
container member functions to accept const_iterator parameters.
Note that this change applies to all library clauses, including
strings.</p>
<p>For example, in 21.3.5.5 change:<br>
<br>
<tt>iterator erase(iterator p);</tt><br>
<br>
to:<br>
<tt>iterator erase(const_iterator p);</tt>
</p>
<p><b>Rationale:</b></p>
<p>The issue was discussed at length. It was generally agreed that 1)
There is no major technical argument against the change (although
there is a minor argument that some obscure programs may break), and
2) Such a change would not break const correctness. The concerns about
making the change were 1) it is user detectable (although only in
boundary cases), 2) it changes a large number of signatures, and 3) it
seems more of a design issue that an out-and-out defect.</p>
<p>The LWG believes that this issue should be considered as part of a
general review of const issues for the next revision of the
standard. Also see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#200">200</a>.</p>
<hr>
<h3><a name="188"></a>188. valarray helpers missing augmented assignment operators</h3>
<p><b>Section:</b> 26.5.2.6 [valarray.cassign] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Gabriel Dos Reis <b>Date:</b> 1999-08-15</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>26.5.2.6 defines augmented assignment operators
valarray<T>::op=(const T&), but fails to provide
corresponding versions for the helper classes. Thus making the
following illegal:</p>
<blockquote>
<pre>#include <valarray>
int main()
{
std::valarray<double> v(3.14, 1999);
v[99] *= 2.0; // Ok
std::slice s(0, 50, 2);
v[s] *= 2.0; // ERROR
}</pre>
</blockquote>
<p>I can't understand the intent of that omission. It makes the
valarray library less intuitive and less useful.</p>
<p><b>Rationale:</b></p>
<p>Although perhaps an unfortunate
design decision, the omission is not a defect in the current
standard. A future standard may wish to add the missing
operators.</p>
<hr>
<h3><a name="190"></a>190. min() and max() functions should be std::binary_functions</h3>
<p><b>Section:</b> 25.3.7 [alg.min.max] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Mark Rintoul <b>Date:</b> 1999-08-26</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.min.max">issues</a> in [alg.min.max].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>Both std::min and std::max are defined as template functions. This
is very different than the definition of std::plus (and similar
structs) which are defined as function objects which inherit
std::binary_function.<br>
<br>
This lack of inheritance leaves std::min and std::max somewhat useless in standard library algorithms which require
a function object that inherits std::binary_function.</p>
<p><b>Rationale:</b></p>
<p>Although perhaps an unfortunate design decision, the omission is not a defect
in the current standard. A future standard may wish to consider additional
function objects.</p>
<hr>
<h3><a name="191"></a>191. Unclear complexity for algorithms such as binary search</h3>
<p><b>Section:</b> 25.3.3 [alg.binary.search] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 1999-10-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.binary.search">issues</a> in [alg.binary.search].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The complexity of binary_search() is stated as "At most
log(last-first) + 2 comparisons", which seems to say that the
algorithm has logarithmic complexity. However, this algorithms is
defined for forward iterators. And for forward iterators, the need to
step element-by-element results into linear complexity. But such a
statement is missing in the standard. The same applies to
lower_bound(), upper_bound(), and equal_range(). <br>
<br>
However, strictly speaking the standard contains no bug here. So this
might considered to be a clarification or improvement.
</p>
<p><b>Rationale:</b></p>
<p>The complexity is expressed in terms of comparisons, and that
complexity can be met even if the number of iterators accessed is
linear. Paragraph 1 already says exactly what happens to
iterators.</p>
<hr>
<h3><a name="192"></a>192. a.insert(p,t) is inefficient and overconstrained</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Ed Brey <b>Date:</b> 1999-06-06</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a></p>
<p><b>Discussion:</b></p>
<p>As defined in 23.1.2, paragraph 7 (table 69), a.insert(p,t) suffers from
several problems:</p>
<table border="1" cellpadding="5">
<tbody><tr>
<td><b>expression</b></td>
<td><b>return type</b></td>
<td><b>pre/post-condition</b></td>
<td><b>complexity</b></td>
</tr>
<tr>
<td><tt>a.insert(p,t)</tt></td>
<td><tt>iterator</tt></td>
<td>inserts t if and only if there is no element with key equivalent to the key of
t in containers with unique keys; always inserts t in containers with equivalent
keys. always returns the iterator pointing to the element with key equivalent to
the key of t . iterator p is a hint pointing to where the insert should start to search.</td>
<td>logarithmic in general, but amortized constant if t is inserted right after p .</td>
</tr>
</tbody></table>
<p>1. For a container with unique keys, only logarithmic complexity is
guaranteed if no element is inserted, even though constant complexity is always
possible if p points to an element equivalent to t.</p>
<p>2. For a container with equivalent keys, the amortized constant complexity
guarantee is only useful if no key equivalent to t exists in the container.
Otherwise, the insertion could occur in one of multiple locations, at least one
of which would not be right after p.</p>
<p>3. By guaranteeing amortized constant complexity only when t is inserted
after p, it is impossible to guarantee constant complexity if t is inserted at
the beginning of the container. Such a problem would not exist if amortized
constant complexity was guaranteed if t is inserted before p, since there is
always some p immediately before which an insert can take place.</p>
<p>4. For a container with equivalent keys, p does not allow specification of
where to insert the element, but rather only acts as a hint for improving
performance. This negates the added functionality that p would provide if it
specified where within a sequence of equivalent keys the insertion should occur.
Specifying the insert location provides more control to the user, while
providing no disadvantage to the container implementation.</p>
<p><b>Proposed resolution:</b></p>
<p>In 23.1.2 [associative.reqmts] paragraph 7, replace the row in table 69
for a.insert(p,t) with the following two rows:</p>
<table border="1" cellpadding="5">
<tbody><tr>
<td><b>expression</b></td>
<td><b>return type</b></td>
<td><b>pre/post-condition</b></td>
<td><b>complexity</b></td>
</tr>
<tr>
<td><tt>a_uniq.insert(p,t)</tt></td>
<td><tt>iterator</tt></td>
<td>inserts t if and only if there is no element with key equivalent to the
key of t. returns the iterator pointing to the element with key equivalent
to the key of t.</td>
<td>logarithmic in general, but amortized constant if t is inserted right
before p or p points to an element with key equivalent to t.</td>
</tr>
<tr>
<td><tt>a_eq.insert(p,t)</tt></td>
<td><tt>iterator</tt></td>
<td>inserts t and returns the iterator pointing to the newly inserted
element. t is inserted right before p if doing so preserves the container
ordering.</td>
<td>logarithmic in general, but amortized constant if t is inserted right
before p.</td>
</tr>
</tbody></table>
<p><b>Rationale:</b></p>
<p>Too big a change. Furthermore, implementors report checking
both before p and after p, and don't want to change this behavior.</p>
<hr>
<h3><a name="194"></a>194. rdbuf() functions poorly specified</h3>
<p><b>Section:</b> 27.4.4 [ios] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Steve Clamage <b>Date:</b> 1999-09-07</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In classic iostreams, base class ios had an rdbuf function that returned a
pointer to the associated streambuf. Each derived class had its own rdbuf
function that returned a pointer of a type reflecting the actual type derived
from streambuf. Because in ARM C++, virtual function overrides had to have the
same return type, rdbuf could not be virtual.</p>
<p>In standard iostreams, we retain the non-virtual rdbuf function design, and
in addition have an overloaded rdbuf function that sets the buffer pointer.
There is no need for the second function to be virtual nor to be implemented in
derived classes.</p>
<p>Minor question: Was there a specific reason not to make the original rdbuf
function virtual?</p>
<p>Major problem: Friendly compilers warn about functions in derived classes
that hide base-class overloads. Any standard implementation of iostreams will
result in such a warning on each of the iostream classes, because of the
ill-considered decision to overload rdbuf only in a base class.</p>
<p>In addition, users of the second rdbuf function must use explicit
qualification or a cast to call it from derived classes. An explicit
qualification or cast to basic_ios would prevent access to any later overriding
version if there was one.</p>
<p>What I'd like to do in an implementation is add a using- declaration for the
second rdbuf function in each derived class. It would eliminate warnings about
hiding functions, and would enable access without using explicit qualification.
Such a change I don't think would change the behavior of any valid program, but
would allow invalid programs to compile:</p>
<blockquote>
<pre> filebuf mybuf;
fstream f;
f.rdbuf(mybuf); // should be an error, no visible rdbuf</pre>
</blockquote>
<p>I'd like to suggest this problem as a defect, with the proposed resolution to
require the equivalent of a using-declaration for the rdbuf function that is not
replaced in a later derived class. We could discuss whether replacing the
function should be allowed.</p>
<p><b>Rationale:</b></p>
<p>For historical reasons, the standard is correct as written. There is a subtle difference between the base
class <tt> rdbuf()</tt> and derived class <tt>rdbuf()</tt>. The derived
class <tt> rdbuf()</tt> always returns the original streambuf, whereas the base class
<tt> rdbuf()</tt> will return the "current streambuf" if that has been changed by the variant you mention.</p>
<p>Permission is not required to add such an extension. See
17.4.4.4 [member.functions].</p>
<hr>
<h3><a name="196"></a>196. Placement new example has alignment problems</h3>
<p><b>Section:</b> 18.5.1.3 [new.delete.placement] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Herb Sutter <b>Date:</b> 1998-12-15</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#new.delete.placement">issues</a> in [new.delete.placement].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a></p>
<p><b>Discussion:</b></p>
<p>The example in 18.5.1.3 [new.delete.placement] paragraph 4 reads: </p>
<blockquote>
<p>[Example: This can be useful for constructing an object at a known address:<br>
<br>
<tt> char place[sizeof(Something)];<br>
Something* p = new (place) Something();<br>
<br>
</tt>end example] </p>
</blockquote>
<p>This example has potential alignment problems. </p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="197"></a>197. max_size() underspecified</h3>
<p><b>Section:</b> 20.1.2 [allocator.requirements], 23.1 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Andy Sawyer <b>Date:</b> 1999-10-21</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#allocator.requirements">active issues</a> in [allocator.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#allocator.requirements">issues</a> in [allocator.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Must the value returned by max_size() be unchanged from call to call? </p>
<p>Must the value returned from max_size() be meaningful? </p>
<p>Possible meanings identified in lib-6827: </p>
<p>1) The largest container the implementation can support given "best
case" conditions - i.e. assume the run-time platform is "configured to
the max", and no overhead from the program itself. This may possibly
be determined at the point the library is written, but certainly no
later than compile time.<br>
<br>
2) The largest container the program could create, given "best case"
conditions - i.e. same platform assumptions as (1), but take into
account any overhead for executing the program itself. (or, roughly
"storage=storage-sizeof(program)"). This does NOT include any resource
allocated by the program. This may (or may not) be determinable at
compile time.<br>
<br>
3) The largest container the current execution of the program could
create, given knowledge of the actual run-time platform, but again,
not taking into account any currently allocated resource. This is
probably best determined at program start-up.<br>
<br>
4) The largest container the current execution program could create at
the point max_size() is called (or more correctly at the point
max_size() returns :-), given it's current environment (i.e. taking
into account the actual currently available resources). This,
obviously, has to be determined dynamically each time max_size() is
called. </p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>max_size() isn't useful for very many things, and the existing
wording is sufficiently clear for the few cases that max_size() can
be used for. None of the attempts to change the existing wording
were an improvement.</p>
<p>It is clear to the LWG that the value returned by max_size() can't
change from call to call.</p>
<hr>
<h3><a name="203"></a>203. basic_istream::sentry::sentry() is uninstantiable with ctype<user-defined type></h3>
<p><b>Section:</b> 27.6.1.1.3 [istream::sentry] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt McClure and Dietmar Kühl <b>Date:</b> 2000-01-01</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream::sentry">issues</a> in [istream::sentry].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>27.6.1.1.2 Paragraph 4 states:</p>
<blockquote>
<p>To decide if the character c is a whitespace character, the constructor
performs ''as if'' it executes the following code fragment: </p>
<pre>const ctype<charT>& ctype = use_facet<ctype<charT> >(is.getloc());
if (ctype.is(ctype.space,c)!=0)
// c is a whitespace character.</pre>
</blockquote>
<p> But Table 51 in 22.1.1.1.1 only requires an implementation to
provide specializations for ctype<char> and
ctype<wchar_t>. If sentry's constructor is implemented using
ctype, it will be uninstantiable for a user-defined character type
charT, unless the implementation has provided non-working (since it
would be impossible to define a correct ctype<charT> specialization
for an arbitrary charT) definitions of ctype's virtual member
functions.</p>
<p>
It seems the intent the standard is that sentry should behave, in
every respect, not just during execution, as if it were implemented
using ctype, with the burden of providing a ctype specialization
falling on the user. But as it is written, nothing requires the
translation of sentry's constructor to behave as if it used the above
code, and it would seem therefore, that sentry's constructor should be
instantiable for all character types.
</p>
<p>
Note: If I have misinterpreted the intent of the standard with
respect to sentry's constructor's instantiability, then a note should
be added to the following effect:
</p>
<blockquote><p>
An implementation is forbidden from using the above code if it renders
the constructor uninstantiable for an otherwise valid character
type.
</p></blockquote>
<p>In any event, some clarification is needed.</p>
<p><b>Rationale:</b></p>
<p>It is possible but not easy to instantiate on types other than char
or wchar_t; many things have to be done first. That is by intention
and is not a defect.</p>
<hr>
<h3><a name="204"></a>204. distance(first, last) when "last" is before "first"</h3>
<p><b>Section:</b> 24.3.4 [iterator.operations] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Rintala Matti <b>Date:</b> 2000-01-28</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Section 24.3.4 describes the function distance(first, last) (where first and
last are iterators) which calculates "the number of increments or
decrements needed to get from 'first' to 'last'".</p>
<p>The function should work for forward, bidirectional and random access
iterators, and there is a requirement 24.3.4.5 which states that "'last'
must be reachable from 'first'".</p>
<p>With random access iterators the function is easy to implement as "last
- first".</p>
<p>With forward iterators it's clear that 'first' must point to a place before
'last', because otherwise 'last' would not be reachable from 'first'.</p>
<p>But what about bidirectional iterators? There 'last' is reachable from
'first' with the -- operator even if 'last' points to an earlier position than
'first'. However, I cannot see how the distance() function could be implemented
if the implementation does not know which of the iterators points to an earlier
position (you cannot use ++ or -- on either iterator if you don't know which
direction is the "safe way to travel").</p>
<p>The paragraph 24.3.4.1 states that "for ... bidirectional iterators they
use ++ to provide linear time implementations". However, the ++ operator is
not mentioned in the reachability requirement. Furthermore 24.3.4.4 explicitly
mentions that distance() returns the number of increments _or decrements_,
suggesting that it could return a negative number also for bidirectional
iterators when 'last' points to a position before 'first'.</p>
<p>Is a further requirement is needed to state that for forward and
bidirectional iterators "'last' must be reachable from 'first' using the ++
operator". Maybe this requirement might also apply to random access
iterators so that distance() would work the same way for every iterator
category?</p>
<p><b>Rationale:</b></p>
<p>"Reachable" is defined in the standard in 24.1 [iterator.requirements] paragraph 6.
The definition is only in terms of operator++(). The LWG sees no defect in
the standard.</p>
<hr>
<h3><a name="205"></a>205. numeric_limits unclear on how to determine floating point types</h3>
<p><b>Section:</b> 18.2.1.2 [numeric.limits.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Steve Cleary <b>Date:</b> 2000-01-28</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#numeric.limits.members">issues</a> in [numeric.limits.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In several places in 18.2.1.2 [numeric.limits.members], a member is
described as "Meaningful for all floating point types."
However, no clear method of determining a floating point type is
provided.</p>
<p>In 18.2.1.5 [numeric.special], paragraph 1 states ". . . (for
example, epsilon() is only meaningful if is_integer is
false). . ." which suggests that a type is a floating point type
if is_specialized is true and is_integer is false; however, this is
unclear.</p>
<p>When clarifying this, please keep in mind this need of users: what
exactly is the definition of floating point? Would a fixed point or
rational representation be considered one? I guess my statement here
is that there could also be types that are neither integer or
(strictly) floating point.</p>
<p><b>Rationale:</b></p>
<p>It is up to the implementor of a user define type to decide if it is a
floating point type.</p>
<hr>
<h3><a name="207"></a>207. ctype<char> members return clause incomplete</h3>
<p><b>Section:</b> 22.2.1.3.2 [facet.ctype.char.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Robert Klarer <b>Date:</b> 1999-11-02</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.ctype.char.members">issues</a> in [facet.ctype.char.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#153">153</a></p>
<p><b>Discussion:</b></p>
<p>
The <tt>widen</tt> and <tt>narrow</tt> member functions are described
in 22.2.1.3.2, paragraphs 9-11. In each case we have two overloaded
signatures followed by a <b>Returns</b> clause. The <b>Returns</b>
clause only describes one of the overloads.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the returns clause in 22.2.1.3.2 [facet.ctype.char.members]
paragraph 10 from:</p>
<p> Returns: do_widen(low, high, to).</p>
<p>to:</p>
<p> Returns: do_widen(c) or do_widen(low, high, to),
respectively.</p>
<p>Change the returns clause in 22.2.1.3.2 [facet.ctype.char.members] paragraph 11
from:</p>
<p> Returns: do_narrow(low, high, to).</p>
<p>to:</p>
<p> Returns: do_narrow(c) or do_narrow(low, high, to),
respectively.</p>
<p><b>Rationale:</b></p>
<p>Subsumed by issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#153">153</a>, which addresses the same
paragraphs.</p>
<hr>
<h3><a name="213"></a>213. Math function overloads ambiguous</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Nico Josuttis <b>Date:</b> 2000-02-26</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Due to the additional overloaded versions of numeric functions for
float and long double according to Section 26.5, calls such as int x;
std::pow (x, 4) are ambiguous now in a standard conforming
implementation. Current implementations solve this problem very
different (overload for all types, don't overload for float and long
double, use preprocessor, follow the standard and get
ambiguities).</p> <p>This behavior should be standardized or at least
identified as implementation defined.</p>
<p><b>Rationale:</b></p>
<p>These math issues are an
understood and accepted consequence of the design. They have
been discussed several times in the past. Users must write casts
or write floating point expressions as arguments.</p>
<hr>
<h3><a name="215"></a>215. Can a map's key_type be const?</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 2000-02-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>A user noticed that this doesn't compile with the Rogue Wave library because
the rb_tree class declares a key_allocator, and allocator<const int> is
not legal, I think:</p>
<blockquote>
<pre>map < const int, ... > // legal?</pre>
</blockquote>
<p>which made me wonder whether it is legal for a map's key_type to be const. In
email from Matt Austern he said:</p>
<blockquote>
<p>I'm not sure whether it's legal to declare a map with a const key type. I
hadn't thought about that question until a couple weeks ago. My intuitive
feeling is that it ought not to be allowed, and that the standard ought to say
so. It does turn out to work in SGI's library, though, and someone in the
compiler group even used it. Perhaps this deserves to be written up as an issue
too.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The "key is assignable" requirement from table 69 in
23.1.2 [associative.reqmts] already implies the key cannot be const.</p>
<hr>
<h3><a name="216"></a>216. setbase manipulator description flawed</h3>
<p><b>Section:</b> 27.6.3 [std.manip] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Hyman Rosen <b>Date:</b> 2000-02-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#std.manip">issues</a> in [std.manip].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#193">193</a></p>
<p><b>Discussion:</b></p>
<p>27.6.3 [std.manip] 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<<s behaves
as if f(s) were called, in is an (instance of) basic_istream then the
expression in>>s behaves as if f(s) were called. Where f can be
defined as:</p>
<pre>ios_base& f(ios_base& 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<<s and in>>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 "and" after the first comma, and the "Where
f" 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="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#193">193</a>.</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>
<hr>
<h3><a name="218"></a>218. Algorithms do not use binary predicate objects for default comparisons</h3>
<p><b>Section:</b> 25.3 [alg.sorting] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Pablo Halpern <b>Date:</b> 2000-03-06</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.sorting">issues</a> in [alg.sorting].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Many of the algorithms take an argument, pred, of template parameter type
BinaryPredicate or an argument comp of template parameter type Compare. These
algorithms usually have an overloaded version that does not take the predicate
argument. In these cases pred is usually replaced by the use of operator== and
comp is replaced by the use of operator<.</p>
<p>This use of hard-coded operators is inconsistent with other parts of the
library, particularly the containers library, where equality is established
using equal_to<> and ordering is established using less<>. Worse,
the use of operator<, would cause the following innocent-looking code to have
undefined behavior:</p>
<blockquote>
<pre>vector<string*> vec;
sort(vec.begin(), vec.end());</pre>
</blockquote>
<p>The use of operator< is not defined for pointers to unrelated objects. If
std::sort used less<> to compare elements, then the above code would be
well-defined, since less<> is explicitly specialized to produce a total
ordering of pointers.</p>
<p><b>Rationale:</b></p>
<p>This use of operator== and operator< was a very deliberate, conscious, and
explicitly made design decision; these operators are often more efficient. The
predicate forms are available for users who don't want to rely on operator== and
operator<.</p>
<hr>
<h3><a name="219"></a>219. find algorithm missing version that takes a binary predicate argument</h3>
<p><b>Section:</b> 25.1.2 [alg.find] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Pablo Halpern <b>Date:</b> 2000-03-06</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.find">issues</a> in [alg.find].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>The find function always searches for a value using operator== to compare the
value argument to each element in the input iterator range. This is inconsistent
with other find-related functions such as find_end and find_first_of, which
allow the caller to specify a binary predicate object to be used for determining
equality. The fact that this can be accomplished using a combination of find_if
and bind_1st or bind_2nd does not negate the desirability of a consistent,
simple, alternative interface to find.</p>
<p><b>Proposed resolution:</b></p>
<blockquote>
<p>In section 25.1.2 [alg.find], add a second prototype for find
(between the existing prototype and the prototype for find_if), as
follows:</p>
<pre> template<class InputIterator, class T, class BinaryPredicate>
InputIterator find(InputIterator first, InputIterator last,
const T& value, BinaryPredicate bin_pred);</pre>
<p>Change the description of the return from:</p>
<blockquote>
<p>Returns: The first iterator i in the range [first, last) for which the following corresponding
conditions hold: *i == value, pred(*i) != false. Returns last if no such iterator is found.</p>
</blockquote>
<p> to:</p>
<blockquote>
<p>Returns: The first iterator i in the range [first, last) for which the following
corresponding condition holds: *i == value, bin_pred(*i,value) != false, pred(*)
!= false. Return last if no such iterator is found.</p>
</blockquote>
</blockquote>
<p><b>Rationale:</b></p>
<p>This is request for a pure extension, so it is not a defect in the
current standard. As the submitter pointed out, "this can
be accomplished using a combination of find_if and bind_1st or
bind_2nd".</p>
<hr>
<h3><a name="236"></a>236. ctype<char>::is() member modifies facet</h3>
<p><b>Section:</b> 22.2.1.3.2 [facet.ctype.char.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dietmar Kühl <b>Date:</b> 2000-04-24</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.ctype.char.members">issues</a> in [facet.ctype.char.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#28">28</a></p>
<p><b>Discussion:</b></p>
<p>The description of the <tt>is()</tt> member in paragraph 4 of 22.2.1.3.2 [facet.ctype.char.members] is broken: According to this description, the
second form of the <tt>is()</tt> method modifies the masks in the
<tt>ctype</tt> object. The correct semantics if, of course, to obtain
an array of masks. The corresponding method in the general case,
ie. the <tt>do_is()</tt> method as described in 22.2.1.1.2 [locale.ctype.virtuals] paragraph 1 does the right thing.</p>
<p><b>Proposed resolution:</b></p>
<p>Change paragraph 4 from</p>
<blockquote><p>
The second form, for all *p in the range [low, high), assigns
vec[p-low] to table()[(unsigned char)*p].
</p></blockquote>
<p>to become</p>
<blockquote><p>
The second form, for all *p in the range [low, high), assigns
table()[(unsigned char)*p] to vec[p-low].
</p></blockquote>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="244"></a>244. Must <tt>find</tt>'s third argument be CopyConstructible?</h3>
<p><b>Section:</b> 25.1.2 [alg.find] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Andrew Koenig <b>Date:</b> 2000-05-02</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.find">issues</a> in [alg.find].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Is the following implementation of <tt>find</tt> acceptable?</p>
<pre> template<class Iter, class X>
Iter find(Iter begin, Iter end, const X& x)
{
X x1 = x; // this is the crucial statement
while (begin != end && *begin != x1)
++begin;
return begin;
}
</pre>
<p>If the answer is yes, then it is implementation-dependent as to
whether the following fragment is well formed:</p>
<pre> vector<string> v;
find(v.begin(), v.end(), "foo");
</pre>
<p>At issue is whether there is a requirement that the third argument
of find be CopyConstructible. There may be no problem here, but
analysis is necessary.</p>
<p><b>Rationale:</b></p>
<p>There is no indication in the standard that find's third argument
is required to be Copy Constructible. The LWG believes that no such
requirement was intended. As noted above, there are times when a user
might reasonably pass an argument that is not Copy Constructible.</p>
<hr>
<h3><a name="245"></a>245. Which operations on <tt>istream_iterator</tt> trigger input operations?</h3>
<p><b>Section:</b> 24.5.1 [istream.iterator] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Andrew Koenig <b>Date:</b> 2000-05-02</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>I do not think the standard specifies what operation(s) on istream
iterators trigger input operations. So, for example:</p>
<pre> istream_iterator<int> i(cin);
int n = *i++;
</pre>
<p>I do not think it is specified how many integers have been read
from cin. The number must be at least 1, of course, but can it be 2?
More?</p>
<p><b>Rationale:</b></p>
<p>The standard is clear as written: the stream is read every time
operator++ is called, and it is also read either when the iterator is
constructed or when operator* is called for the first time. In the
example above, exactly two integers are read from cin.</p>
<p>There may be a problem with the interaction between istream_iterator
and some STL algorithms, such as find. There are no guarantees about
how many times find may invoke operator++.</p>
<hr>
<h3><a name="246"></a>246. <tt>a.insert(p,t)</tt> is incorrectly specified</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Mark Rodgers <b>Date:</b> 2000-05-19</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a></p>
<p><b>Discussion:</b></p>
<p>Closed issue 192 raised several problems with the specification of
this function, but was rejected as Not A Defect because it was too big
a change with unacceptable impacts on existing implementations.
However, issues remain that could be addressed with a smaller change
and with little or no consequent impact.</p>
<ol>
<li><p> The specification is inconsistent with the original
proposal and with several implementations.</p>
<p>The initial implementation by Hewlett Packard only ever looked
immediately <i>before</i> p, and I do not believe there was any
intention to standardize anything other than this behavior.
Consequently, current implementations by several leading
implementors also look immediately before p, and will only insert
after p in logarithmic time. I am only aware of one implementation
that does actually look after p, and it looks before p as well. It
is therefore doubtful that existing code would be relying on the
behavior defined in the standard, and it would seem that fixing
this defect as proposed below would standardize existing
practice.</p></li>
<li><p>
The specification is inconsistent with insertion for sequence
containers.</p>
<p>This is difficult and confusing to teach to newcomers. All
insert operations that specify an iterator as an insertion location
should have a consistent meaning for the location represented by
that iterator.</p></li>
<li><p> As specified, there is no way to hint that the insertion
should occur at the beginning of the container, and the way to hint
that it should occur at the end is long winded and unnatural.</p>
<p>For a container containing n elements, there are n+1 possible
insertion locations and n+1 valid iterators. For there to be a
one-to-one mapping between iterators and insertion locations, the
iterator must represent an insertion location immediately before
the iterator.</p></li>
<li><p> When appending sorted ranges using insert_iterators,
insertions are guaranteed to be sub-optimal.</p>
<p>In such a situation, the optimum location for insertion is
always immediately after the element previously inserted. The
mechanics of the insert iterator guarantee that it will try and
insert after the element after that, which will never be correct.
However, if the container first tried to insert before the hint,
all insertions would be performed in amortized constant
time.</p></li>
</ol>
<p><b>Proposed resolution:</b></p>
<p>In 23.1.2 [lib.associative.reqmts] paragraph 7, table 69, make
the following changes in the row for a.insert(p,t):</p>
<p><i>assertion/note pre/post condition:</i>
<br>Change the last sentence from</p>
<blockquote><p>
"iterator p is a hint pointing to where the insert should
start to search."
</p></blockquote>
<p>to</p>
<blockquote><p>
"iterator p is a hint indicating that immediately before p
may be a correct location where the insertion could occur."
</p></blockquote>
<p><i>complexity:</i><br>
Change the words "right after" to "immediately before".</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="249"></a>249. Return Type of <tt>auto_ptr::operator=</tt></h3>
<p><b>Section:</b> D.9.1 [auto.ptr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Joseph Gottman <b>Date:</b> 2000-06-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#auto.ptr">issues</a> in [auto.ptr].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>According to section 20.4.5, the function
<tt>auto_ptr::operator=()</tt> returns a reference to an auto_ptr.
The reason that <tt>operator=()</tt> usually returns a reference is to
facilitate code like</p>
<pre> int x,y,z;
x = y = z = 1;
</pre>
<p>However, given analogous code for <tt>auto_ptr</tt>s,</p>
<pre> auto_ptr<int> x, y, z;
z.reset(new int(1));
x = y = z;
</pre>
<p>the result would be that <tt>z</tt> and <tt>y</tt> would both be set to
NULL, instead of all the <tt>auto_ptr</tt>s being set to the same value.
This makes such cascading assignments useless and counterintuitive for
<tt>auto_ptr</tt>s.</p>
<p><b>Proposed resolution:</b></p>
<p>Change <tt>auto_ptr::operator=()</tt> to return <tt>void</tt> instead
of an <tt>auto_ptr</tt> reference.</p>
<p><b>Rationale:</b></p>
<p>The return value has uses other than cascaded assignments: a user can
call an auto_ptr member function, pass the auto_ptr to a
function, etc. Removing the return value could break working user
code.</p>
<hr>
<h3><a name="257"></a>257. STL functional object and iterator inheritance.</h3>
<p><b>Section:</b> 20.5.3 [base], 24.3.2 [iterator.basic] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Robert Dick <b>Date:</b> 2000-08-17</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#base">issues</a> in [base].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
According to the November 1997 Draft Standard, the results of deleting an
object of a derived class through a pointer to an object of its base class are
undefined if the base class has a non-virtual destructor. Therefore, it is
potentially dangerous to publicly inherit from such base classes.
</p>
<p>Defect:
<br>
The STL design encourages users to publicly inherit from a number of classes
which do nothing but specify interfaces, and which contain non-virtual
destructors.
</p>
<p>Attribution:
<br>
Wil Evers and William E. Kempf suggested this modification for functional
objects.
</p>
<p><b>Proposed resolution:</b></p>
<p>
When a base class in the standard library is useful only as an interface
specifier, i.e., when an object of the class will never be directly
instantiated, specify that the class contains a protected destructor. This
will prevent deletion through a pointer to the base class without performance,
or space penalties (on any implementation I'm aware of).
</p>
<p>
As an example, replace...
</p>
<pre> template <class Arg, class Result>
struct unary_function {
typedef Arg argument_type;
typedef Result result_type;
};
</pre>
<p>
... with...
</p>
<pre> template <class Arg, class Result>
struct unary_function {
typedef Arg argument_type;
typedef Result result_type;
protected:
~unary_function() {}
};
</pre>
<p>
Affected definitions:
<br>
20.3.1 [lib.function.objects] -- unary_function, binary_function
<br>
24.3.2 [lib.iterator.basic] -- iterator
</p>
<p><b>Rationale:</b></p>
<p>
The standard is clear as written; this is a request for change, not a
defect in the strict sense. The LWG had several different objections
to the proposed change. One is that it would prevent users from
creating objects of type <tt>unary_function</tt> and
<tt>binary_function</tt>. Doing so can sometimes be legitimate, if users
want to pass temporaries as traits or tag types in generic code.
</p>
<hr>
<h3><a name="267"></a>267. interaction of strstreambuf::overflow() and seekoff()</h3>
<p><b>Section:</b> D.7.1.3 [depr.strstreambuf.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2000-10-05</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#depr.strstreambuf.virtuals">issues</a> in [depr.strstreambuf.virtuals].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
It appears that the interaction of the strstreambuf members overflow()
and seekoff() can lead to undefined behavior in cases where defined
behavior could reasonably be expected. The following program
demonstrates this behavior:
</p>
<pre> #include <strstream>
int main ()
{
std::strstreambuf sb;
sb.sputc ('c');
sb.pubseekoff (-1, std::ios::end, std::ios::in);
return !('c' == sb.sgetc ());
}
</pre>
<p>
D.7.1.1, p1 initializes strstreambuf with a call to basic_streambuf<>(),
which in turn sets all pointers to 0 in 27.5.2.1, p1.
</p>
<p>
27.5.2.2.5, p1 says that basic_streambuf<>::sputc(c) calls
overflow(traits::to_int_type(c)) if a write position isn't available (it
isn't due to the above).
</p>
<p>
D.7.1.3, p3 says that strstreambuf::overflow(off, ..., ios::in) makes at
least one write position available (i.e., it allows the function to make
any positive number of write positions available).
</p>
<p>
D.7.1.3, p13 computes newoff = seekhigh - eback(). In D.7.1, p4 we see
seekhigh = epptr() ? epptr() : egptr(), or seekhigh = epptr() in this
case. newoff is then epptr() - eback().
</p>
<p>
D.7.1.4, p14 sets gptr() so that gptr() == eback() + newoff + off, or
gptr() == epptr() + off holds.
</p>
<p>
If strstreambuf::overflow() made exactly one write position available
then gptr() will be set to just before epptr(), and the program will
return 0. Buf if the function made more than one write position
available, epptr() and gptr() will both point past pptr() and the
behavior of the program is undefined.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the last sentence of D.7.1 [depr.strstreambuf] paragraph 4 from</p>
<blockquote><p>
Otherwise, seeklow equals gbeg and seekhigh is either pend, if
pend is not a null pointer, or gend.
</p></blockquote>
<p>to become</p>
<blockquote><p>
Otherwise, seeklow equals gbeg and seekhigh is either gend if
0 == pptr(), or pbase() + max where max is the maximum value of
pptr() - pbase() ever reached for this stream.
</p></blockquote>
<p><i>[
pre-Copenhagen: Dietmar provided wording for proposed resolution.
]</i></p>
<p><i>[
post-Copenhagen: Fixed a typo: proposed resolution said to fix
4.7.1, not D.7.1.
]</i></p>
<p><b>Rationale:</b></p>
<p>This is related to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#65">65</a>: it's not clear what it
means to seek beyond the current area. Without resolving issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#65">65</a> we can't resolve this. As with issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#65">65</a>,
the library working group does not wish to invest time nailing down
corner cases in a deprecated feature.</p>
<hr>
<h3><a name="269"></a>269. cstdarg and unnamed parameters</h3>
<p><b>Section:</b> 18.7 [support.exception] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> J. Stephen Adamczyk <b>Date:</b> 2000-10-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#support.exception">issues</a> in [support.exception].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
One of our customers asks whether this is valid C++:
</p>
<pre> #include <cstdarg>
void bar(const char *, va_list);
void
foo(const char *file, const char *, ...)
{
va_list ap;
va_start(ap, file);
bar(file, ap);
va_end(ap);
}
</pre>
<p>
The issue being whether it is valid to use cstdarg when the final
parameter before the "..." is unnamed. cstdarg is, as far
as I can tell, inherited verbatim from the C standard. and the
definition there (7.8.1.1 in the ISO C89 standard) refers to "the
identifier of the rightmost parameter". What happens when there
is no such identifier?
</p>
<p>
My personal opinion is that this should be allowed, but some tweak
might be required in the C++ standard.
</p>
<p><b>Rationale:</b></p>
<p>
Not a defect, the C and C++ standards are clear. It is impossible to
use varargs if the parameter immediately before "..." has no
name, because that is the parameter that must be passed to va_start.
The example given above is broken, because va_start is being passed
the wrong parameter.
</p>
<p>
There is no support for extending varargs to provide additional
functionality beyond what's currently there. For reasons of C/C++
compatibility, it is especially important not to make gratuitous
changes in this part of the C++ standard. The C committee has already
been requested not to touch this part of the C standard unless
necessary.
</p>
<hr>
<h3><a name="277"></a>277. Normative encouragement in allocator requirements unclear</h3>
<p><b>Section:</b> 20.1.2 [allocator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2000-11-07</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#allocator.requirements">active issues</a> in [allocator.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#allocator.requirements">issues</a> in [allocator.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In 20.1.5, paragraph 5, the standard says that "Implementors are
encouraged to supply libraries that can accept allocators that
encapsulate more general memory models and that support non-equal
instances." This is intended as normative encouragement to
standard library implementors. However, it is possible to interpret
this sentence as applying to nonstandard third-party libraries.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 20.1.5, paragraph 5, change "Implementors" to
"Implementors of the library described in this International
Standard".
</p>
<p><b>Rationale:</b></p>
<p>The LWG believes the normative encouragement is already
sufficiently clear, and that there are no important consequences
even if it is misunderstood.</p>
<hr>
<h3><a name="279"></a>279. const and non-const iterators should have equivalent typedefs</h3>
<p><b>Section:</b> 23.1 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Steve Cleary <b>Date:</b> 2000-11-27</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements">active issues</a> in [container.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements">issues</a> in [container.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
This came from an email from Steve Cleary to Fergus in reference to
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#179">179</a>. The library working group briefly discussed
this in Toronto and believes it should be a separate issue.
</p>
<p>
Steve said: "We may want to state that the const/non-const iterators must have
the same difference type, size_type, and category."
</p>
<p>
(Comment from Judy)
I'm not sure if the above sentence should be true for all
const and non-const iterators in a particular container, or if it means
the container's iterator can't be compared with the container's
const_iterator unless the above it true. I suspect the former.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In <b>Section:</b> 23.1 [container.requirements],
table 65, in the assertion/note pre/post condition for X::const_iterator,
add the following:
</p>
<blockquote>
<p>
typeid(X::const_iterator::difference_type) == typeid(X::iterator::difference_type)
</p>
<p>
typeid(X::const_iterator::size_type) == typeid(X::iterator::size_type)
</p>
<p>
typeid(X::const_iterator::category) == typeid(X::iterator::category)
</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>Going through the types one by one: Iterators don't have a
<tt>size_type</tt>. We already know that the difference types are
identical, because the container requirements already say that the
difference types of both X::iterator and X::const_iterator are both
X::difference_type. The standard does not require that X::iterator
and X::const_iterator have the same iterator category, but the LWG
does not see this as a defect: it's possible to imagine cases in which
it would be useful for the categories to be different.</p>
<p>It may be desirable to require X::iterator and X::const_iterator to
have the same value type, but that is a new issue. (Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#322">322</a>.)</p>
<hr>
<h3><a name="287"></a>287. conflicting ios_base fmtflags</h3>
<p><b>Section:</b> 27.4.2.2 [fmtflags.state] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 2000-12-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#fmtflags.state">issues</a> in [fmtflags.state].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The Effects clause for ios_base::setf(fmtflags fmtfl) says
"Sets fmtfl in flags()". What happens if the user first calls
ios_base::scientific and then calls ios_base::fixed or vice-versa?
This is an issue for all of the conflicting flags, i.e. ios_base::left
and ios_base::right or ios_base::dec, ios_base::hex and ios_base::oct.
</p>
<p>
I see three possible solutions:
</p>
<ol>
<li>Set ios_base::failbit whenever the user specifies a conflicting
flag with one previously explicitly set. If the constructor is
supposed to set ios_base::dec (see discussion below), then
the user setting hex or oct format after construction will not
set failbit. </li>
<li>The last call to setf "wins", i.e. it clears any conflicting
previous setting.</li>
<li>All the flags that the user specifies are set, but when actually
interpreting them, fixed always override scientific, right always
overrides left, dec overrides hex which overrides oct.</li>
</ol>
<p>
Most existing implementations that I tried seem to conform to resolution #3,
except that when using the iomanip manipulator hex or oct then that always
overrides dec, but calling setf(ios_base::hex) doesn't.
</p>
<p>
There is a sort of related issue, which is that although the ios_base
constructor says that each ios_base member has an indeterminate value
after construction, all the existing implementations I tried explicitly set
ios_base::dec.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>
<tt>adjustfield</tt>, <tt>basefield</tt>, and <tt>floatfield</tt>
are each multi-bit fields. It is possible to set multiple bits within
each of those fields. (For example, <tt>dec</tt> and
<tt>oct</tt>). These fields are used by locale facets. The LWG
reviewed the way in which each of those three fields is used, and
believes that in each case the behavior is well defined for any
possible combination of bits. See for example Table 58, in 22.2.2.2.2
[facet.num.put.virtuals], noting the requirement in paragraph 6 of that
section.
</p>
<p>
Users are advised to use manipulators, or else use the two-argument
version of <tt>setf</tt>, to avoid unexpected behavior.
</p>
<hr>
<h3><a name="289"></a>289. <cmath> requirements missing C float and long double versions</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 2000-12-30</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In ISO/IEC 9899:1990 Programming Languages C we find the following
concerning <math.h>:
</p>
<blockquote><p>
7.13.4 Mathematics <math.h>
<br>
The names of all existing functions declared in the <math.h>
header, suffixed with f or l, are reserved respectively for
corresponding functions with float and long double arguments
are return values.
</p></blockquote>
<p>
For example, <tt>float sinf(float)</tt>
is reserved.
</p>
<p>
In the C99 standard, <math.h> must contain declarations
for these functions.
</p>
<p>
So, is it acceptable for an implementor to add these prototypes to the
C++ versions of the math headers? Are they required?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add these Functions to Table 80, section 26.5 and to Table 99,
section C.2:
</p>
<pre> acosf asinf atanf atan2f ceilf cosf coshf
expf fabsf floorf fmodf frexpf ldexpf
logf log10f modff powf sinf sinhf sqrtf
tanf tanhf
acosl asinl atanl atan2l ceill cosl coshl
expl fabsl floorl fmodl frexpl ldexpl
logl log10l modfl powl sinl sinhl sqrtl
tanl tanhl
</pre>
<p>
There should probably be a note saying that these functions
are optional and, if supplied, should match the description in
the 1999 version of the C standard. In the next round
of C++ standardization they can then become mandatory.
</p>
<p><b>Rationale:</b></p>
<p>The C90 standard, as amended, already permits (but does not
require) these functions, and the C++ standard incorporates the
C90 standard by reference. C99 is not an issue, because it is
never referred to by the C++ standard.</p>
<hr>
<h3><a name="293"></a>293. Order of execution in transform algorithm</h3>
<p><b>Section:</b> 25.2.4 [alg.transform] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Angelika Langer <b>Date:</b> 2001-01-04</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.transform">issues</a> in [alg.transform].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>This issue is related to issue 242. In case that the resolution
proposed for issue 242 is accepted, we have have the following
situation: The 4 numeric algorithms (accumulate and consorts) as well
as transform would allow a certain category of side effects. The
numeric algorithms specify that they invoke the functor "for
every iterator i in the range [first, last) in order". transform,
in contrast, would not give any guarantee regarding order of
invocation of the functor, which means that the functor can be invoked
in any arbitrary order.
</p>
<p>Why would that be a problem? Consider an example: say the
transformator that is a simple enumerator ( or more generally
speaking, "is order-sensitive" ). Since a standard
compliant implementation of transform is free to invoke the enumerator
in no definite order, the result could be a garbled enumeration.
Strictly speaking this is not a problem, but it is certainly at odds
with the prevalent understanding of transform as an algorithms that
assigns "a new _corresponding_ value" to the output
elements.
</p>
<p>All implementations that I know of invoke the transformator in
definite order, namely starting from first and proceeding to last -
1. Unless there is an optimization conceivable that takes advantage of
the indefinite order I would suggest to specify the order, because it
eliminate the uncertainty that users would otherwise have regarding
the order of execution of their potentially order-sensitive function
objects.
</p>
<p><b>Proposed resolution:</b></p>
<p>In section 25.2.3 - Transform [lib.alg.transform] change:</p>
<blockquote><p>
-1- Effects: Assigns through every iterator i in the range [result,
result + (last1 - first1)) a new corresponding
value equal to op(*(first1 + (i - result)) or binary_op(*(first1 +
(i - result), *(first2 + (i - result))).
</p></blockquote>
<p>to:</p>
<blockquote><p>
-1- Effects: Computes values by invoking the operation op or binary_op
for every iterator in the range [first1, last1) in order. Assigns through
every iterator i in the range [result, result + (last1 - first1)) a new
corresponding
value equal to op(*(first1 + (i - result)) or binary_op(*(first1 +
(i - result), *(first2 + (i - result))).
</p></blockquote>
<p><b>Rationale:</b></p>
<p>For Input Iterators an order is already guaranteed, because
only one order is possible. If a user who passes a Forward
Iterator to one of these algorithms really needs a specific
order of execution, it's possible to achieve that effect by
wrapping it in an Input Iterator adaptor.</p>
<hr>
<h3><a name="296"></a>296. Missing descriptions and requirements of pair operators</h3>
<p><b>Section:</b> 20.2.3 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2001-01-14</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The synopsis of the header <tt><utility></tt> in 20.2 [utility]
lists the complete set of equality and relational operators for <tt>pair</tt>
but the section describing the template and the operators only describes
<tt>operator==()</tt> and <tt>operator<()</tt>, and it fails to mention
any requirements on the template arguments. The remaining operators are
not mentioned at all.
</p>
<p><b>Rationale:</b></p>
<p>20.2.1 [operators] paragraph 10 already specifies the semantics.
That paragraph says that, if declarations of operator!=, operator>,
operator<=, and operator>= appear without definitions, they are
defined as specified in 20.2.1 [operators]. There should be no user
confusion, since that paragraph happens to immediately precede the
specification of <tt>pair</tt>.</p>
<hr>
<h3><a name="302"></a>302. Need error indication from codecvt<>::do_length</h3>
<p><b>Section:</b> 22.2.1.5 [locale.codecvt.byname] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Gregory Bumgardner <b>Date:</b> 2001-01-25</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt.byname">issues</a> in [locale.codecvt.byname].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The effects of <tt>codecvt<>::do_length()</tt> are described in
22.2.1.5.2, paragraph 10. As implied by that paragraph, and clarified
in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#75">75</a>, <tt>codecvt<>::do_length()</tt> must
process the source data and update the <tt>stateT</tt> argument just
as if the data had been processed by <tt>codecvt<>::in()</tt>.
However, the standard does not specify how <tt>do_length()</tt> would
report a translation failure, should the source sequence contain
untranslatable or illegal character sequences.
</p>
<p>
The other conversion methods return an "error" result value
to indicate that an untranslatable character has been encountered, but
<tt>do_length()</tt> already has a return value (the number of source
characters that have been processed by the method).
</p>
<p><b>Proposed resolution:</b></p>
<p>
This issue cannot be resolved without modifying the interface. An exception
cannot be used, as there would be no way to determine how many characters
have been processed and the state object would be left in an indeterminate
state.
</p>
<p>
A source compatible solution involves adding a fifth argument to length()
and do_length() that could be used to return position of the offending
character sequence. This argument would have a default value that would
allow it to be ignored:
</p>
<pre> int length(stateT& state,
const externT* from,
const externT* from_end,
size_t max,
const externT** from_next = 0);
virtual
int do_length(stateT& state,
const externT* from,
const externT* from_end,
size_t max,
const externT** from_next);
</pre>
<p>
Then an exception could be used to report any translation errors and
the from_next argument, if used, could then be used to retrieve the
location of the offending character sequence.
</p>
<p><b>Rationale:</b></p>
<p>The standard is already clear: the return value is the number of
"valid complete characters". If it encounters an invalid sequence of
external characters, it stops.</p>
<hr>
<h3><a name="304"></a>304. Must <tt>*a</tt> return an lvalue when <tt>a</tt> is an input iterator?</h3>
<p><b>Section:</b> 24.1 [iterator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Dave Abrahams <b>Date:</b> 2001-02-05</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
We all "know" that input iterators are allowed to produce
values when dereferenced of which there is no other in-memory copy.
</p>
<p>
But: Table 72, with a careful reading, seems to imply that this can only be
the case if the value_type has no members (e.g. is a built-in type).
</p>
<p>The problem occurs in the following entry:</p>
<pre> a->m pre: (*a).m is well-defined
Equivalent to (*a).m
</pre>
<p>
<tt>*a.m</tt> can be well-defined if <tt>*a</tt> is not a reference
type, but since <tt>operator->()</tt> must return a pointer for
<tt>a->m</tt> to be well-formed, it needs something to return a
pointer <i>to</i>. This seems to indicate that <tt>*a</tt> must be
buffered somewhere to make a legal input iterator.
</p>
<p>I don't think this was intentional.</p>
<p><b>Rationale:</b></p>
<p>The current standard is clear and consistent. Input iterators that
return rvalues are in fact implementable. They may in some cases
require extra work, but it is still possible to define an operator->
in such cases: it doesn't have to return a T*, but may return a
proxy type. No change to the standard is justified.</p>
<hr>
<h3><a name="313"></a>313. set_terminate and set_unexpected question</h3>
<p><b>Section:</b> 18.7.3.3 [terminate] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Judy Ward <b>Date:</b> 2001-04-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#terminate">issues</a> in [terminate].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
According to section 18.7.3.3 of the standard, std::terminate() is
supposed to call the terminate_handler in effect immediately after
evaluating the throw expression.
</p>
<p>
Question: what if the terminate_handler in effect is itself
std::terminate?
</p>
<p>For example:</p>
<pre> #include <exception>
int main () {
std::set_terminate(std::terminate);
throw 5;
return 0;
}
</pre>
<p>
Is the implementation allowed to go into an infinite loop?
</p>
<p>
I think the same issue applies to std::set_unexpected.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>Infinite recursion is to be expected: users who set the terminate
handler to <tt>terminate</tt> are explicitly asking for <tt>terminate</tt>
to call itself.</p>
<hr>
<h3><a name="314"></a>314. Is the stack unwound when terminate() is called?</h3>
<p><b>Section:</b> 18.7.3.3 [terminate] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Detlef Vollmann <b>Date:</b> 2001-04-11</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#terminate">issues</a> in [terminate].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The standard appears to contradict itself about whether the stack is
unwound when the implementation calls terminate().
</p>
<p>From 18.7.3.3p2:</p>
<blockquote><p>
Calls the terminate_handler function in effect immediately
after evaluating the throw-expression (lib.terminate.handler),
if called by the implementation [...]
</p></blockquote>
<p>So the stack is guaranteed not to be unwound.</p>
<p>But from 15.3p9:</p>
<blockquote><p>
[...]whether or not the stack is unwound before this call
to terminate() is implementation-defined (except.terminate).
</p></blockquote>
<p>
And 15.5.1 actually defines that in most cases the stack is unwound.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>There is definitely no contradiction between the core and library
clauses; nothing in the core clauses says that stack unwinding happens
after <tt>terminate</tt> is called. 18.7.3.3p2 does not say anything
about when terminate() is called; it merely specifies which
<tt>terminate_handler</tt> is used.</p>
<hr>
<h3><a name="323"></a>323. abs() overloads in different headers</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Dave Abrahams <b>Date:</b> 2001-06-04</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>Currently the standard mandates the following overloads of
abs():</p>
<pre> abs(long), abs(int) in <cstdlib>
abs(float), abs(double), abs(long double) in <cmath>
template<class T> T abs(const complex<T>&) in <complex>
template<class T> valarray<T> abs(const valarray<T>&); in <valarray>
</pre>
<p>
The problem is that having only some overloads visible of a function
that works on "implicitly inter-convertible" types is dangerous in
practice. The headers that get included at any point in a translation
unit can change unpredictably during program
development/maintenance. The wrong overload might be unintentionally
selected.
</p>
<p>
Currently, there is nothing that mandates the simultaneous visibility
of these overloads. Indeed, some vendors have begun fastidiously
reducing dependencies among their (public) headers as a QOI issue: it
helps people to write portable code by refusing to compile unless all
the correct headers are #included.
</p>
<p>The same issue may exist for other functions in the library.</p>
<p>Redmond: PJP reports that C99 adds two new kinds of abs: complex,
and int_max_abs.</p>
<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#343">343</a>.</p>
<p><b>Rationale:</b></p>
<p>The programs that could potentially be broken by this situation are
already fragile, and somewhat contrived: For example, a user-defined
class that has conversion overloads both to <tt>long</tt> and
to <tt>float</tt>. If <tt>x</tt> is a value of such a class, then
<tt>abs(x)</tt> would give the <tt>long</tt> version if the user
included <cstdlib>, the <tt>float</tt> version if the user
included <cmath>, and would be diagnosed as ambiguous at
compile time if the user included both headers. The LWG couldn't
find an example of a program whose meaning would be changed (as
opposed to changing it from well-formed to ill-formed) simply by
adding another standard header.</p>
<p>Since the harm seems minimal, and there don't seem to be any simple
and noninvasive solutions, this is being closed as NAD. It is
marked as "Future" for two reasons. First, it might be useful to
define an <tt><all></tt> header that would include all
Standard Library headers. Second, we should at least make sure that
future library extensions don't make this problem worse.</p>
<hr>
<h3><a name="326"></a>326. Missing typedef in moneypunct_byname</h3>
<p><b>Section:</b> 22.2.6.4 [locale.moneypunct.byname] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2001-07-05</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The definition of the moneypunct facet contains the typedefs char_type
and string_type. Only one of these names, string_type, is defined in
the derived facet, moneypunct_byname.</p>
<p><b>Proposed resolution:</b></p>
<p>For consistency with the numpunct facet, add a typedef for
char_type to the definition of the moneypunct_byname facet in
22.2.6.4 [locale.moneypunct.byname].</p>
<p><b>Rationale:</b></p>
<p>The absence of the typedef is irrelevant. Users can still access
the typedef, because it is inherited from the base class.</p>
<hr>
<h3><a name="330"></a>330. Misleading "exposition only" value in class locale definition</h3>
<p><b>Section:</b> 22.1.1 [locale] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2001-07-15</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale">issues</a> in [locale].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The "exposition only" value of the std::locale::none constant shown in
the definition of class locale is misleading in that it on many
systems conflicts with the value assigned to one if the LC_XXX
constants (specifically, LC_COLLATE on AIX, LC_ALL on HP-UX, LC_CTYPE
on Linux and SunOS). This causes incorrect behavior when such a
constant is passed to one of the locale member functions that accept a
locale::category argument and interpret it as either the C LC_XXX
constant or a bitmap of locale::category values. At least three major
implementations adopt the suggested value without a change and
consequently suffer from this problem.
</p>
<p>
For instance, the following code will (presumably) incorrectly copy facets
belonging to the collate category from the German locale on AIX:
</p>
<pre> std::locale l (std::locale ("C"), "de_DE", std::locale::none);
</pre>
<p><b>Rationale:</b></p>
<p>The LWG agrees that it may be difficult to implement locale member
functions in such a way that they can take either <tt>category</tt>
arguments or the LC_ constants defined in <cctype>. In light of
this requirement (22.1.1.1.1 [locale.category], paragraph 2), and in light
of the requirement in the preceding paragraph that it is possible to
combine <tt>category</tt> bitmask elements with bitwise operations,
defining the <tt>category</tt> elements is delicate,
particularly if an implementor is constrained to work with a
preexisting C library. (Just using the existing LC_ constants would
not work in general.) There's no set of "exposition only" values that
could give library implementors proper guidance in such a delicate
matter. The non-normative example we're giving is no worse than
any other choice would be.</p>
<p>See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#347">347</a>.</p>
<hr>
<h3><a name="332"></a>332. Consider adding increment and decrement operators to std::fpos< T > </h3>
<p><b>Section:</b> 27.4.3 [fpos] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> PremAnand M. Rao <b>Date:</b> 2001-08-27</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#fpos">issues</a> in [fpos].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Increment and decrement operators are missing from
Table 88 -- Position type requirements in 27.4.3 [fpos].
</p>
<p><b>Proposed resolution:</b></p>
<p>
Table 88 (section 27.4.3) -- Position type requirements
be updated to include increment and decrement operators.
</p>
<pre>expression return type operational note
++p fpos& p += O(1)
p++ fpos { P tmp = p;
++p;
return tmp; }
--p fpos& p -= O(1)
p-- fpos { P tmp = p;
--p;
return tmp; }
</pre>
<p><b>Rationale:</b></p>
<p>The LWG believes this is a request for extension, not a defect
report. Additionally, nobody saw a clear need for this extension;
<tt>fpos</tt> is used only in very limited ways.</p>
<hr>
<h3><a name="344"></a>344. grouping + showbase</h3>
<p><b>Section:</b> 22.2.2 [category.numeric] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Howard Hinnant <b>Date:</b> 2001-10-13</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
When both grouping and showbase are active and the basefield is octal,
does the leading 0 participate in the grouping or not? For example,
should one format as: 0,123,456 or 0123,456?
</p>
<p>
An analogy can be drawn with hexadecimal. It appears that 0x123,456 is
preferred over 0x,123,456. However, this analogy is not universally
accepted to apply to the octal base. The standard is not clear on how
to format (or parse) in this manner.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Insert into 22.2.3.1.2 [facet.numpunct.virtuals] paragraph 3, just before the last
sentence:
</p>
<blockquote><p>
The leading hexadecimal base specifier "0x" does not participate in
grouping. The leading '0' octal base specifier may participate in
grouping. It is unspecified if the leading '0' participates in
formatting octal numbers. In parsing octal numbers, the implementation
is encouraged to accept both the leading '0' participating in the
grouping, and not participating (e.g. 0123,456 or 0,123,456).
</p></blockquote>
<p><b>Rationale:</b></p>
<p>
The current behavior may be unspecified, but it's not clear that it
matters. This is an obscure corner case, since grouping is usually
intended for the benefit of humans and oct/hex prefixes are usually
intended for the benefit of machines. There is not a strong enough
consensus in the LWG for action.
</p>
<hr>
<h3><a name="348"></a>348. Minor issue with std::pair operator<</h3>
<p><b>Section:</b> 20.2.3 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Andy Sawyer <b>Date:</b> 2001-10-23</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The current wording of 20.2.2 [lib.pairs] p6 precludes the use of
operator< on any pair type which contains a pointer.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 20.2.3 [pairs] paragraph 6, replace:</p>
<pre> Returns: x.first < y.first || (!(y.first < x.first) && x.second <
y.second).
</pre>
<p>With:</p>
<pre> Returns: std::less<T1>()( x.first, y.first ) ||
(!std::less<T1>()( y.first, x.first) &&
std::less<T2>()( x.second, y.second ) )
</pre>
<p><b>Rationale:</b></p>
<p>This is an instance of a much more general problem. If we want
operator< to translate to std::less for pairs of pointers, where
do we draw the line? The same issue applies to individual
pointers, smart pointer wrappers, std::vector<T*>, and so
on.</p>
<p>Andy Koenig suggests that the real issue here is that we aren't
distinguishing adequately between two different orderings, a
"useful ordering" and a "canonical ordering" that's used just
because we sometimes need <i>some</i> ordering without caring much
which ordering it is. Another example of the later is typeinfo's
<tt>before</tt>.</p>
<hr>
<h3><a name="350"></a>350. allocator<>::address</h3>
<p><b>Section:</b> 20.6.1.1 [allocator.members], 20.1.2 [allocator.requirements], 17.4.1.1 [contents] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Nathan Myers <b>Date:</b> 2001-10-25</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#allocator.members">issues</a> in [allocator.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#634">634</a></p>
<p><b>Discussion:</b></p>
<p>See c++std-lib-9006 and c++std-lib-9007. This issue is taken
verbatim from -9007.</p>
<p>
The core language feature allowing definition of operator&() applied
to any non-builtin type makes that operator often unsafe to use in
implementing libraries, including the Standard Library. The result
is that many library facilities fail for legal user code, such as
the fragment</p>
<pre> class A { private: A* operator&(); };
std::vector<A> aa;
class B { };
B* operator&(B&) { return 0; }
std::vector<B> ba;
</pre>
<p>
In particular, the requirements table for Allocator (Table 32) specifies
no semantics at all for member address(), and allocator<>::address is
defined in terms of unadorned operator &.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 20.6.1.1, Change the definition of allocator<>::address from:</p>
<blockquote><p>
Returns: &x
</p></blockquote>
<p>to:</p>
<p>
Returns: The value that the built in operator&(x) would return if not
overloaded.
</p>
<p>
In 20.1.6, Table 32, add to the Notes column of the a.address(r) and
a.address(s) lines, respectively:
</p>
<pre> allocator<T>::address(r)
allocator<T>::address(s)
</pre>
<p>In addition, in clause 17.4.1.1, add a statement:</p>
<blockquote><p>
The Standard Library does not apply operator& to any type for which
operator& may be overloaded.
</p></blockquote>
<p><b>Rationale:</b></p>
<p>The LWG believes both examples are ill-formed. The contained type
is required to be CopyConstructible (20.1.1 [utility.arg.requirements]), and that
includes the requirement that &t return the usual types and
values. Since allocators are intended to be used in conjunction with
containers, and since the CopyConstructible requirements appear to
have been written to deal with the concerns of this issue, the LWG
feels it is NAD unless someone can come up with a well-formed example
exhibiting a problem.</p>
<p>It may well be that the CopyConstructible requirements are too
restrictive and that either the container requirements or the
CopyConstructive requirements should be relaxed, but that's a far
larger issue. Marking this issue as "future" as a pointer to that
larger issue.</p>
<hr>
<h3><a name="351"></a>351. unary_negate and binary_negate: struct or class?</h3>
<p><b>Section:</b> 20.5 [function.objects] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Dale Riley <b>Date:</b> 2001-11-12</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#function.objects">issues</a> in [function.objects].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In 20.5 [function.objects] the header <functional> synopsis declares
the unary_negate and binary_negate function objects as struct.
However in 20.5.10 [negators] the unary_negate and binary_negate
function objects are defined as class. Given the context, they are
not "basic function objects" like negate, so this is either a typo or
an editorial oversight.
</p>
<p><i>[Taken from comp.std.c++]</i></p>
<p><b>Proposed resolution:</b></p>
<p>Change the synopsis to reflect the useage in 20.5.10 [negators]</p>
<p><i>[Curaçao: Since the language permits "struct", the LWG
views this as NAD. They suggest, however, that the Project Editor
might wish to make the change as editorial.]</i></p>
<hr>
<h3><a name="353"></a>353. <tt>std::pair</tt> missing template assignment</h3>
<p><b>Section:</b> 20.2.3 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2001-12-02</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The class template <tt>std::pair</tt> defines a template ctor (20.2.2, p4) but
no template assignment operator. This may lead to inefficient code since
assigning an object of <tt>pair<C, D></tt> to <tt>pair<A, B></tt>
where the types <tt>C</tt> and <tt>D</tt> are distinct from but convertible to
<tt>A</tt> and <tt>B</tt>, respectively, results in a call to the template copy
ctor to construct an unnamed temporary of type <tt>pair<A, B></tt>
followed by an ordinary (perhaps implicitly defined) assignment operator,
instead of just a straight assignment.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add the following declaration to the definition of <tt>std::pair</tt>:
</p>
<pre> template<class U, class V>
pair& operator=(const pair<U, V> &p);
</pre>
<p>
And also add a paragraph describing the effects of the function template to the
end of 20.2.2:
</p>
<pre> template<class U, class V>
pair& operator=(const pair<U, V> &p);
</pre>
<p>
<b>Effects</b>: <tt>first = p.first;</tt>
<tt>second = p.second;</tt>
<b>Returns</b>: <tt>*this</tt>
</p>
<p><i>[Curaçao: There is no indication this is was anything other than
a design decision, and thus NAD. May be appropriate for a future
standard.]</i></p>
<hr>
<h3><a name="356"></a>356. Meaning of ctype_base::mask enumerators</h3>
<p><b>Section:</b> 22.2.1 [category.ctype] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2002-01-23</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#category.ctype">issues</a> in [category.ctype].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>What should the following program print?</p>
<pre> #include <locale>
#include <iostream>
class my_ctype : public std::ctype<char>
{
typedef std::ctype<char> base;
public:
my_ctype(std::size_t refs = 0) : base(my_table, false, refs)
{
std::copy(base::classic_table(), base::classic_table() + base::table_size,
my_table);
my_table[(unsigned char) '_'] = (base::mask) (base::print | base::space);
}
private:
mask my_table[base::table_size];
};
int main()
{
my_ctype ct;
std::cout << "isspace: " << ct.is(std::ctype_base::space, '_') << " "
<< "isalpha: " << ct.is(std::ctype_base::alpha, '_') << std::endl;
}
</pre>
<p>The goal is to create a facet where '_' is treated as whitespace.</p>
<p>On gcc 3.0, this program prints "isspace: 1 isalpha: 0". On
Microsoft C++ it prints "isspace: 1 isalpha: 1".</p>
<p>
I believe that both implementations are legal, and the standard does not
give enough guidance for users to be able to use std::ctype's
protected interface portably.</p>
<p>
The above program assumes that ctype_base::mask enumerators like
<tt>space</tt> and <tt>print</tt> are disjoint, and that the way to
say that a character is both a space and a printing character is to or
those two enumerators together. This is suggested by the "exposition
only" values in 22.2.1 [category.ctype], but it is nowhere specified in
normative text. An alternative interpretation is that the more
specific categories subsume the less specific. The above program
gives the results it does on the Microsoft compiler because, on that
compiler, <tt>print</tt> has all the bits set for each specific
printing character class.
</p>
<p>From the point of view of std::ctype's public interface, there's no
important difference between these two techniques. From the point of
view of the protected interface, there is. If I'm defining a facet
that inherits from std::ctype<char>, I'm the one who defines the
value that table()['a'] returns. I need to know what combination of
mask values I should use. This isn't so very esoteric: it's exactly
why std::ctype has a protected interface. If we care about users
being able to write their own ctype facets, we have to give them a
portable way to do it.
</p>
<p>
Related reflector messages:
lib-9224, lib-9226, lib-9229, lib-9270, lib-9272, lib-9273, lib-9274,
lib-9277, lib-9279.
</p>
<p>Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#339">339</a> is related, but not identical. The
proposed resolution if issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#339">339</a> says that
ctype_base::mask must be a bitmask type. It does not say that the
ctype_base::mask elements are bitmask elements, so it doesn't
directly affect this issue.</p>
<p>More comments from Benjamin Kosnik, who believes that
that C99 compatibility essentially requires what we're
calling option 1 below.</p>
<blockquote>
<pre>I think the C99 standard is clear, that isspace -> !isalpha.
--------
#include <locale>
#include <iostream>
class my_ctype : public std::ctype<char>
{
private:
typedef std::ctype<char> base;
mask my_table[base::table_size];
public:
my_ctype(std::size_t refs = 0) : base(my_table, false, refs)
{
std::copy(base::classic_table(), base::classic_table() + base::table_size,
my_table);
mask both = base::print | base::space;
my_table[static_cast<mask>('_')] = both;
}
};
int main()
{
using namespace std;
my_ctype ct;
cout << "isspace: " << ct.is(ctype_base::space, '_') << endl;
cout << "isprint: " << ct.is(ctype_base::print, '_') << endl;
// ISO C99, isalpha iff upper | lower set, and !space.
// 7.5, p 193
// -> looks like g++ behavior is correct.
// 356 -> bitmask elements are required for ctype_base
// 339 -> bitmask type required for mask
cout << "isalpha: " << ct.is(ctype_base::alpha, '_') << endl;
}
</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Informally, we have three choices:</p>
<ol>
<li>Require that the enumerators are disjoint (except for alnum and
graph)</li>
<li>Require that the enumerators are not disjoint, and specify which
of them subsume which others. (e.g. mandate that lower includes alpha
and print)</li>
<li>Explicitly leave this unspecified, which the result that the above
program is not portable.</li>
</ol>
<p>Either of the first two options is just as good from the standpoint
of portability. Either one will require some implementations to
change.</p>
<p><b>Rationale:</b></p>
<p>The LWG agrees that this is a real ambiguity, and that both
interpretations are conforming under the existing standard. However,
there's no evidence that it's causing problems for real users. Users
who want to define ctype facets portably can test the ctype_base masks
to see which interpretation is being used.</p>
<hr>
<h3><a name="357"></a>357. <cmath> float functions cannot return HUGE_VAL</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Ray Lischner <b>Date:</b> 2002-02-26</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The float versions of the math functions have no meaningful value to return
for a range error. The long double versions have a value they can return,
but it isn't necessarily the most reasonable value.
</p>
<p>
Section 26.5 [lib.c.math], paragraph 5, says that C++ "adds float and long
double overloaded versions of these functions, with the same semantics,"
referring to the math functions from the C90 standard.
</p>
<p>
The C90 standard, in section 7.5.1, paragraph 3, says that functions return
"the value of the macro HUGE_VAL" when they encounter a range error.
Section 7.5, paragraph 2, defines HUGE_VAL as a macro that "expands to a
positive double expression, not necessarily representable as a float."
</p>
<p>
Therefore, the float versions of the math functions have no way to
signal a range error. <i>[Curaçao: The LWG notes that this isn't
strictly correct, since errno is set.]</i> The semantics require that they
return HUGE_VAL, but they cannot because HUGE_VAL might not be
representable as a float.
</p>
<p>
The problem with long double functions is less severe because HUGE_VAL is
representable as a long double. On the other hand, it might not be a "huge"
long double value, and might fall well within the range of normal return
values for a long double function. Therefore, it does not make sense for a
long double function to return a double (HUGE_VAL) for a range error.
</p>
<p><b>Proposed resolution:</b></p>
<p>Curaçao: C99 was faced with a similar problem, which they fixed by
adding HUGE_VALF and HUGE_VALL in addition to HUGE_VAL.</p>
<p>C++ must also fix, but it should be done in the context of the
general C99 based changes to C++, not via DR. Thus the LWG in Curaçao
felt the resolution should be NAD, FUTURE, but the issue is being held
open for one more meeting to ensure LWG members not present during the
discussion concur.</p>
<p><b>Rationale:</b></p>
<p>Will be fixed as part of more general work in the TR.</p>
<hr>
<h3><a name="361"></a>361. num_get<>::do_get (..., void*&) checks grouping</h3>
<p><b>Section:</b> 22.2.2.2.2 [facet.num.put.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2002-03-12</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.num.put.virtuals">issues</a> in [facet.num.put.virtuals].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
22.2.2.2.2, p12 specifies that <tt>thousands_sep</tt> is to be inserted only
for integral types (issue 282 suggests that this should be done for
all arithmetic types).
</p>
<p>
22.2.2.1.2, p12 requires that grouping be checked for all extractors
including that for <tt>void*</tt>.
</p>
<p>
I don't think that's right. <tt>void*</tt> values should not be checked for
grouping, should they? (Although if they should, then <tt>num_put</tt> needs
to write them out, otherwise their extraction will fail.)
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the first sentence of 22.2.2.2.2, p12 from
</p>
<blockquote><p>
Digit grouping is checked. That is, the positions of discarded
separators is examined for consistency with
use_facet<numpunct<charT> >(loc).grouping().
If they are not consistent then ios_base::failbit is assigned
to err.
</p></blockquote>
<p>to</p>
<blockquote><p>
Except for conversions to void*, digit grouping is checked...
</p></blockquote>
<p><b>Rationale:</b></p>
<p>This would be a change: as it stands, the standard clearly
specifies that grouping applies to void*. A survey of existing
practice shows that most existing implementations do that, as they
should.</p>
<hr>
<h3><a name="366"></a>366. Excessive const-qualification</h3>
<p><b>Section:</b> 27 [input.output] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown, Marc Paterno <b>Date:</b> 2002-05-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#input.output">issues</a> in [input.output].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The following member functions are declared const, yet return non-const
pointers. We believe they are should be changed, because they allow code
that may surprise the user. See document N1360 for details and
rationale.
</p>
<p><i>[Santa Cruz: the real issue is that we've got const member
functions that return pointers to non-const, and N1360 proposes
replacing them by overloaded pairs. There isn't a consensus about
whether this is a real issue, since we've never said what our
constness policy is for iostreams. N1360 relies on a distinction
between physical constness and logical constness; that distinction, or
those terms, does not appear in the standard.]</i></p>
<p><b>Proposed resolution:</b></p>
<p>In 27.4.4 and 27.4.4.2</p>
<p>Replace</p>
<pre> basic_ostream<charT,traits>* tie() const;
</pre>
<p>with</p>
<pre> basic_ostream<charT,traits>* tie();
const basic_ostream<charT,traits>* tie() const;
</pre>
<p>and replace</p>
<pre> basic_streambuf<charT,traits>* rdbuf() const;
</pre>
<p>with</p>
<pre> basic_streambuf<charT,traits>* rdbuf();
const basic_streambuf<charT,traits>* rdbuf() const;
</pre>
<p>In 27.5.2 and 27.5.2.3.1</p>
<p>Replace</p>
<pre> char_type* eback() const;
</pre>
<p>with</p>
<pre> char_type* eback();
const char_type* eback() const;
</pre>
<p>Replace</p>
<pre> char_type gptr() const;
</pre>
<p>with</p>
<pre> char_type* gptr();
const char_type* gptr() const;
</pre>
<p>Replace</p>
<pre> char_type* egptr() const;
</pre>
<p>with</p>
<pre> char_type* egptr();
const char_type* egptr() const;
</pre>
<p>In 27.5.2 and 27.5.2.3.2</p>
<p>Replace</p>
<pre> char_type* pbase() const;
</pre>
<p>with</p>
<pre> char_type* pbase();
const char_type* pbase() const;
</pre>
<p>Replace</p>
<pre> char_type* pptr() const;
</pre>
<p>with</p>
<pre> char_type* pptr();
const char_type* pptr() const;
</pre>
<p>Replace</p>
<pre> char_type* epptr() const;
</pre>
<p>with</p>
<pre> char_type* epptr();
const char_type* epptr() const;
</pre>
<p>In 27.7.2, 27.7.2.2, 27.7.3 27.7.3.2, 27.7.4, and 27.7.6</p>
<p>Replace</p>
<pre> basic_stringbuf<charT,traits,Allocator>* rdbuf() const;
</pre>
<p>with</p>
<pre> basic_stringbuf<charT,traits,Allocator>* rdbuf();
const basic_stringbuf<charT,traits,Allocator>* rdbuf() const;
</pre>
<p>In 27.8.1.5, 27.8.1.7, 27.8.1.8, 27.8.1.10, 27.8.1.11, and 27.8.1.13</p>
<p>Replace</p>
<pre> basic_filebuf<charT,traits>* rdbuf() const;
</pre>
<p>with</p>
<pre> basic_filebuf<charT,traits>* rdbuf();
const basic_filebuf<charT,traits>* rdbuf() const;
</pre>
<p><b>Rationale:</b></p>
<p>The existing specification is a bit sloppy, but there's no
particular reason to change this other than tidiness, and there are
a number of ways in which streams might have been designed
differently if we were starting today. There's no evidence that the
existing constness policy is harming users. We might consider
a different constness policy as part of a full stream redesign.</p>
<hr>
<h3><a name="367"></a>367. remove_copy/remove_copy_if and Input Iterators</h3>
<p><b>Section:</b> 25.2.8 [alg.remove] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Anthony Williams <b>Date:</b> 2002-05-13</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.remove">issues</a> in [alg.remove].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
remove_copy and remove_copy_if (25.2.8 [alg.remove]) permit their
input range to be marked with Input Iterators. However, since two
operations are required against the elements to copy (comparison and
assigment), when the input range uses Input Iterators, a temporary
copy must be taken to avoid dereferencing the iterator twice. This
therefore requires the value type of the InputIterator to be
CopyConstructible. If the iterators are at least Forward Iterators,
then the iterator can be dereferenced twice, or a reference to the
result maintained, so the temporary is not required.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add "If InputIterator does not meet the requirements of forward
iterator, then the value type of InputIterator must be copy
constructible. Otherwise copy constructible is not required." to
25.2.8 [alg.remove] paragraph 6.
</p>
<p><b>Rationale:</b></p>
<p>The assumption is that an input iterator can't be dereferenced
twice. There's no basis for that assumption in the Standard.</p>
<hr>
<h3><a name="368"></a>368. basic_string::replace has two "Throws" paragraphs</h3>
<p><b>Section:</b> 21.3.6.6 [string::replace] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Beman Dawes <b>Date:</b> 2002-06-03</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
21.3.6.6 [string::replace] basic_string::replace, second
signature, given in paragraph 1, has two "Throws" paragraphs (3 and
5).
</p>
<p>
In addition, the second "Throws" paragraph (5) includes specification
(beginning with "Otherwise, the function replaces ...") that should be
part of the "Effects" paragraph.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>This is editorial. Both "throws" statements are true. The bug is
just that the second one should be a sentence, part of the "Effects"
clause, not a separate "Throws". The project editor has been
notified.</p>
<hr>
<h3><a name="372"></a>372. Inconsistent description of stdlib exceptions</h3>
<p><b>Section:</b> 17.4.4.8 [res.on.exception.handling], 18.6.1 [type.info] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Randy Maddox <b>Date:</b> 2002-07-22</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#res.on.exception.handling">issues</a> in [res.on.exception.handling].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>Paragraph 3 under clause 17.4.4.8 [res.on.exception.handling], Restrictions on
Exception Handling, states that "Any other functions defined in the
C++ Standard Library that do not have an exception-specification may
throw implementation-defined exceptions unless otherwise specified."
This statement is followed by a reference to footnote 178 at the
bottom of that page which states, apparently in reference to the C++
Standard Library, that "Library implementations are encouraged (but
not required) to report errors by throwing exceptions from (or derived
from) the standard exceptions."</p>
<p>These statements appear to be in direct contradiction to clause
18.6.1 [type.info], which states "The class exception defines the
base class for the types of objects thrown as exceptions by the C++
Standard library components ...".</p>
<p>Is this inconsistent?</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>Clause 17 is setting the overall library requirements, and it's
clear and consistent. This sentence from Clause 18 is descriptive,
not setting a requirement on any other class.
</p>
<hr>
<h3><a name="374"></a>374. moneypunct::frac_digits returns int not unsigned</h3>
<p><b>Section:</b> 22.2.6.3.1 [locale.moneypunct.members], 22.2.6.3.2 [locale.moneypunct.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Ray Lischner <b>Date:</b> 2002-08-08</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In section 22.2.6.3.1 [locale.moneypunct.members], frac_digits() returns type
"int". This implies that frac_digits() might return a negative value,
but a negative value is nonsensical. It should return "unsigned".
</p>
<p>
Similarly, in section 22.2.6.3.2 [locale.moneypunct.virtuals], do_frac_digits()
should return "unsigned".
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>Regardless of whether the return value is int or unsigned, it's
always conceivable that frac_digits might return a nonsensical
value. (Is 4294967295 really any better than -1?) The clients of
moneypunct, the get and put facets, can and do perform range
checks.</p>
<hr>
<h3><a name="377"></a>377. basic_string::insert and length_error</h3>
<p><b>Section:</b> 21.3.6.4 [string::insert] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Ray Lischner <b>Date:</b> 2002-08-16</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string::insert">issues</a> in [string::insert].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Section 21.3.6.4 [string::insert], paragraph 4, contains the following,
"Then throws length_error if size() >= npos - rlen."
</p>
<p>
Related to DR 83, this sentence should probably be removed.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p><p>This requirement is redundant but correct. No change is
needed.</p>
<hr>
<h3><a name="378"></a>378. locale immutability and locale::operator=()</h3>
<p><b>Section:</b> 22.1.1 [locale] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2002-09-06</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale">issues</a> in [locale].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#31">31</a></p>
<p><b>Discussion:</b></p>
<p>
I think there is a problem with 22.1.1, p6 which says that
</p>
<pre> -6- An instance of locale is immutable; once a facet reference
is obtained from it, that reference remains usable as long
as the locale value itself exists.
</pre>
<p>
and 22.1.1.2, p4:
</p>
<pre> const locale& operator=(const locale& other) throw();
-4- Effects: Creates a copy of other, replacing the current value.
</pre>
<p>
How can a reference to a facet obtained from a locale object remain
valid after an assignment that clearly must replace all the facets
in the locale object? Imagine a program such as this
</p>
<pre> std::locale loc ("de_DE");
const std::ctype<char> &r0 = std::use_facet<std::ctype<char> >(loc);
loc = std::locale ("en_US");
const std::ctype<char> &r1 = std::use_facet<std::ctype<char> >(loc);
</pre>
<p>
Is r0 really supposed to be preserved and destroyed only when loc goes
out of scope?
</p>
<p><b>Proposed resolution:</b></p>
<p><i>[Summer '04 mid-meeting mailing: Martin and Dietmar believe this
is a duplicate of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#31">31</a> and recommend that it be
closed.
]</i></p>
<hr>
<h3><a name="385"></a>385. Does call by value imply the CopyConstructible requirement?</h3>
<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2002-10-23</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Many function templates have parameters that are passed by value;
a typical example is <tt>find_if</tt>'s <i>pred</i> parameter in
25.1.2 [alg.find]. Are the corresponding template parameters
(<tt>Predicate</tt> in this case) implicitly required to be
CopyConstructible, or does that need to be spelled out explicitly?
</p>
<p>
This isn't quite as silly a question as it might seem to be at first
sight. If you call <tt>find_if</tt> in such a way that template
argument deduction applies, then of course you'll get call by value
and you need to provide a copy constructor. If you explicitly provide
the template arguments, however, you can force call by reference by
writing something like <tt>find_if<my_iterator,
my_predicate&></tt>. The question is whether implementation
are required to accept this, or whether this is ill-formed because
my_predicate& is not CopyConstructible.
</p>
<p>
The scope of this problem, if it is a problem, is unknown. Function
object arguments to generic algorithms in clauses 25 [algorithms]
and 26 [numerics] are obvious examples. A review of the whole
library is necessary.
</p>
<p><i>[
This is really two issues. First, predicates are typically passed by
value but we don't say they must be Copy Constructible. They should
be. Second: is specialization allowed to transform value arguments
into references? References aren't copy constructible, so this should
not be allowed.
]</i></p>
<p><i>[
2007-01-12, Howard: First, despite the note above, references <b>are</b>
copy constructible. They just aren't assignable. Second, this is very
closely related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a> and should be consistent with that.
That issue already says that implementations are allowed to copy
function objects. If one passes in a reference, it is copyable, but
susceptible to slicing if one passes in a reference to a base. Third,
with rvalue reference in the language one only needs to satisfy
MoveConstructible to pass an rvalue "by value". Though the function
might still copy the function object internally (requiring
CopyConstructible). Finally (and fwiw), if we wanted to, it is easy to
code all of the std::algorithms such that they do not copy function
objects internally. One merely passes them by reference internally if
desired (this has been fully implemented and shipped for several years).
If this were mandated, it would reverse <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a>, allowing
function objects to reliably maintain state. E.g. the example in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a> would reliably remove only the third element.
]</i></p>
<p><b>Proposed resolution:</b></p>
<p>
Recommend NAD.
</p>
<p><b>Rationale:</b></p>
<p>
Generic algorithms will be marked with concepts and these will imply a requirement
of MoveConstructible (not CopyConstructible). The signature of the function will
then precisely describe and enforce the precise requirements.
</p>
<hr>
<h3><a name="388"></a>388. Use of complex as a key in associative containers</h3>
<p><b>Section:</b> 26.3 [complex.numbers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Gabriel Dos Reis <b>Date:</b> 2002-11-08</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#complex.numbers">issues</a> in [complex.numbers].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Practice with std::complex<> and the associative containers
occasionally reveals artificial and distracting issues with constructs
resembling: std::set<std::complex<double> > s;
</p>
<p>
The main reason for the above to fail is the absence of an approriate
definition for std::less<std::complex<T> >. That in turn comes from
the definition of the primary template std::less<> in terms of
operator<.
</p>
<p>
The usual argument goes as follows: Since there is no ordering over
the complex field compatible with field operations it makes little
sense to define a function operator< operating on the datatype
std::complex<T>. That is fine. However, that reasoning does not carry
over to std::less<T> which is used, among other things, by associative
containers as an ordering useful to meet complexity requirements.
</p>
<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#348">348</a>.</p>
<p><b>Proposed resolution:</b></p>
<p>Informally: Add a specialization of std::less for std::complex.</p>
<p><b>Rationale:</b></p>
<p>Discussed in Santa Cruz. An overwhelming majority of the LWG
believes this should not be treated a DR: it's a request for a design
change, not a defect in the existing standard. Most people (10-3)
believed that we probably don't want this change, period: as with
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#348">348</a>, it's hard to know where to draw the line.
The LWG noted that users who want to put objects into an associative
container for which <tt>operator<</tt> isn't defined can simply
provide their own comparison function object.</p>
<hr>
<h3><a name="390"></a>390. CopyConstructible requirements too strict</h3>
<p><b>Section:</b> 20.1.1 [utility.arg.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">NAD Future</a>
<b>Submitter:</b> Doug Gregor <b>Date:</b> 2002-10-24</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#utility.arg.requirements">active issues</a> in [utility.arg.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#utility.arg.requirements">issues</a> in [utility.arg.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Future">NAD Future</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The CopyConstructible requirements in Table 30 state that for an
object t of type T (where T is CopyConstructible), the expression &t
returns the address of t (with type T*). This requirement is overly
strict, in that it disallows types that overload operator& to not
return a value of type T*. This occurs, for instance, in the <a href="http://www.boost.org/libs/lambda">Boost.Lambda</a> library, where
operator& is overloaded for a Boost.Lambda function object to return
another function object.
</p>
<p>Example:</p>
<pre> std::vector<int> u, v;
int x;
// ...
std::transform(u.begin(), u.end(), std::back_inserter(v), _1 * x);
</pre>
<p>
_1 * x returns an unnamed function object with operator& overloaded to
not return T* , therefore rendering the std::transform call ill-formed.
However, most standard library implementations will compile this code
properly, and the viability of such binder libraries is severely hindered
by the unnecessary restriction in the CopyConstructible requirements.
</p>
<p>
For reference, the address of an object can be retrieved without using
the address-of operator with the following function template:
</p>
<pre> template <typename T> T* addressof(T& v)
{
return reinterpret_cast<T*>(
&const_cast<char&>(reinterpret_cast<const volatile char &>(v)));
}
</pre>
<p>
Note: this relates directly to library issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, which
will need to be reexamined if the CopyConstructible requirements
change.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Remove the last two rows of Table 30, eliminating the requirements
that &t and &u return the address of t and u, respectively.
</p>
<p><b>Rationale:</b></p>
<p>This was a deliberate design decision. Perhaps it should be
reconsidered for C++0x. </p>
<hr>
<h3><a name="392"></a>392. 'equivalence' for input iterators</h3>
<p><b>Section:</b> 24.1.1 [input.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Corwin Joy <b>Date:</b> 2002-12-11</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#input.iterators">issues</a> in [input.iterators].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In section 24.1.1 [input.iterators] table 72 -
'Input Iterator Requirements' we have as a postcondition of *a:
"If a==b and (a, b) is in the domain of == then *a is equivalent to *b".
</p>
<p>
In section 24.5.3.5 [istreambuf.iterator::equal] it states that
"istreambuf_iterator::equal returns true if and only if both iterators
are at end-of-stream, or neither is at end-of-stream, <i>regardless of
what streambuf object they use</i>." (My emphasis).
</p>
<p>
The defect is that either 'equivalent' needs to be more precisely
defined or the conditions for equality in 24.5.3.5 [istreambuf.iterator::equal]
are incorrect. (Or both).
</p>
<p>Consider the following example:</p>
<pre> #include <iostream>
#include <fstream>
#include <iterator>
using namespace std;
int main() {
ifstream file1("file1.txt"), file2("file2.txt");
istreambuf_iterator<char> f1(file1), f2(file2);
cout << "f1 == f2 : " << boolalpha << (f1 == f2) << endl;
cout << "f1 = " << *f1 << endl;
cout << "f2 = " << *f2 << endl;
return 0;
}
</pre>
<p>Now assuming that neither f1 or f2 are at the end-of-stream then
f1 == f2 by 24.5.3.5 [istreambuf.iterator::equal].</p>
<p>However, it is unlikely that *f1 will give the same value as *f2 except
by accident.</p>
<p>So what does *f1 'equivalent' to *f2 mean? I think the standard should
be clearer on this point, or at least be explicit that this does not
mean that *f1 and *f2 are required to have the same value in the case
of input iterators.</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p><p>The two iterators aer not in the domain of ==</p>
<hr>
<h3><a name="393"></a>393. do_in/do_out operation on state unclear</h3>
<p><b>Section:</b> 22.2.1.4.2 [locale.codecvt.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Pending NAD Editorial</a>
<b>Submitter:</b> Alberto Barbati <b>Date:</b> 2002-12-24</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#locale.codecvt.virtuals">active issues</a> in [locale.codecvt.virtuals].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt.virtuals">issues</a> in [locale.codecvt.virtuals].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Pending%20NAD%20Editorial">Pending NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
this DR follows the discussion on the previous thread "codecvt::do_in
not consuming external characters". It's just a clarification issue
and not a request for a change.
</p>
<p>
Can do_in()/do_out() produce output characters without consuming input
characters as a result of operation on state?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add a note at the end of 22.2.1.4.2 [locale.codecvt.virtuals],
paragraph 3:
</p>
<p>
[Note: As a result of operations on state, it can return ok or partial
and set from_next == from and to_next != to. --end note]
</p>
<p><b>Rationale:</b></p>
<p>
The submitter believes that standard already provides an affirmative
answer to the question. However, the current wording has induced a few
library implementors to make the incorrect assumption that
do_in()/do_out() always consume at least one internal character when
they succeed.
</p>
<p>
The submitter also believes that the proposed resolution is not in
conflict with the related issue 76. Moreover, by explicitly allowing
operations on state to produce characters, a codecvt implementation
may effectively implement N-to-M translations without violating the
"one character at a time" principle described in such issue. On a side
note, the footnote in the proposed resolution of issue 76 that
informally rules out N-to-M translations for basic_filebuf should be
removed if this issue is accepted as valid.
</p>
<p><i>[
Kona (2007): The proposed resolution is to add a note. Since this is
non-normative, the issue is editorial, but we believe that the note is
correct. Proposed Disposition: NAD, Editorial
]</i></p>
<hr>
<h3><a name="399"></a>399. volations of unformatted input function requirements</h3>
<p><b>Section:</b> 27.6.1.3 [istream.unformatted] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2003-01-05</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream.unformatted">issues</a> in [istream.unformatted].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The Effects clauses for the two functions below violate the
general requirements on unformatted input functions outlined
in 27.6.1.3: they do not begin by constructing a sentry object.
Instead, they begin by calling widen ('\n'), which may throw
an exception. The exception is then allowed to propagate from
the unformatted input function irrespective of the setting of
exceptions().
</p>
<p>
Note that in light of 27.6.1.1, p3 and p4, the fact that the
functions allow exceptions thrown from widen() to propagate
may not strictly speaking be a defect (but the fact that the
functions do not start by constructing a sentry object still
is). However, since an exception thrown from ctype<charT>
::widen() during any other input operation (say, from within
a call to num_get<charT>::get()) will be caught and cause
badbit to be set, these two functions should not be treated
differently for the sake of consistency.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>
Not a defect. The standard is consistent, and the behavior required
by the standard is unambiguous. Yes, it's theoretically possible for
widen to throw. (Not that this will happen for the default ctype
facet or for most real-world replacement ctype facets.) Users who
define ctype facets that can throw, and who care about this behavior,
can use alternative signatures that don't call widen.
</p>
<hr>
<h3><a name="429"></a>429. typo in basic_ios::clear(iostate)</h3>
<p><b>Section:</b> 27.4.4.3 [iostate.flags] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2003-09-18</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iostate.flags">issues</a> in [iostate.flags].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#412">412</a></p>
<p><b>Discussion:</b></p>
<p>
The Effects clause in 27.4.4.3, p5 describing the effects of a call to
the ios_base member function clear(iostate state) says that the function
only throws if the respective bits are already set prior to the function
call. That's obviously not the intent. If it was, a call to clear(badbit)
on an object for which (rdstate() == goodbit && exceptions() == badbit)
holds would not result in an exception being thrown.
</p>
<p><b>Proposed resolution:</b></p>
<p>
The text ought to be changed from
<br>
"If (rdstate() & exceptions()) == 0, returns. ..."
<br>
to
<br>
"If (state & exceptions()) == 0, returns. ..."
</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="433"></a>433. Contradiction in specification of unexpected()</h3>
<p><b>Section:</b> 18.7.2.4 [unexpected] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Vyatcheslav Sysoltsev <b>Date:</b> 2003-09-29</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Clause 15.5.2 [except.unexpected] paragraph 1 says that "void unexpected();
is called (18.7.2) immediately after completing the stack unwinding
for the former function", but 18.7.2.4 (Effects) says that "void
unexpected(); . . . Calls the unexpected_handler function in effect
immediately after evaluating the throwexpression (18.7.2.2),". Isn't
here a contradiction: 15.5.2 requires stack have been unwound when in
void unexpected() and therefore in unexpected_handler but 18.7.2.4
claims that unexpected_handler is called "in effect immediately" after
evaluation of throw expression is finished, so there is no space left
for stack to be unwound therefore? I think the phrase "in effect
immediately" should be removed from the standard because it brings
ambiguity in understanding.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>There is no contradiction. The phrase "in effect immediately" is
just to clarify which handler is to be called.</p>
<hr>
<h3><a name="437"></a>437. Formatted output of function pointers is confusing</h3>
<p><b>Section:</b> 27.6.2.6.2 [ostream.inserters.arithmetic] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Ivan Godard <b>Date:</b> 2003-10-24</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ostream.inserters.arithmetic">issues</a> in [ostream.inserters.arithmetic].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Given:
</p>
<pre>void f(int) {}
void(*g)(int) = f;
cout << g;
</pre>
<p>
(with the expected #include and usings), the value printed is a rather
surprising "true". Rather useless too.
</p>
<p>The standard defines:</p>
<pre>ostream& operator<<(ostream&, void*);</pre>
<p>which picks up all data pointers and prints their hex value, but does
not pick up function pointers because there is no default conversion
from function pointer to void*. Absent that, we fall back to legacy
conversions from C and the function pointer is converted to bool.
</p>
<p>There should be an analogous inserter that prints the address of a
function pointer.</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>This is indeed a wart, but there is no good way to solve it. C
doesn't provide a portable way of outputting the address of a
function point either.</p>
<hr>
<h3><a name="439"></a>439. Should facets be copyable?</h3>
<p><b>Section:</b> 22.2 [locale.categories] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2003-11-02</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#locale.categories">active issues</a> in [locale.categories].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.categories">issues</a> in [locale.categories].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The following facets classes have no copy constructors described in
the standard, which, according to the standard, means that they are
supposed to use the compiler-generated defaults. Default copy
behavior is probably inappropriate. We should either make these
classes uncopyable or else specify exactly what their constructors do.</p>
<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#421">421</a>.</p>
<pre> ctype_base
ctype
ctype_byname
ctype<char>
ctype_byname<char>
codecvt_base
codecvt
codecvt_byname
num_get
num_put
numpunct
numpunct_byname
collate
collate_byname
time_base
time_get
time_get_byname
time_put
time_put_byname
money_get
money_put
money_base
moneypunct
moneypunct_byname
messages_base
messages
messages_byname
</pre>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>The copy constructor in the base class is private.</p>
<hr>
<h3><a name="440"></a>440. Should std::complex use unqualified transcendentals?</h3>
<p><b>Section:</b> 26.3.8 [complex.transcendentals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2003-11-05</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Operations like <tt>pow</tt> and <tt>exp</tt> on
<tt>complex<T></tt> are typically implemented in terms of
operations like <tt>sin</tt> and <tt>cos</tt> on <tt>T</tt>.
Should implementations write this as <tt>std::sin</tt>, or as plain
unqualified <tt>sin</tt>?
</p>
<p>The issue, of course, is whether we want to use
argument-dependent lookup in the case where <tt>T</tt> is a
user-defined type. This is similar to the issue of valarray
transcendentals, as discussed in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>.</p>
<p>This issue differs from valarray transcendentals in two important
ways. First, "the effect of instantiating the template
<tt>complex</tt> for types other than float, double or long double is
unspecified." (26.3.1 [complex.synopsis]) Second, the standard does not
dictate implementation, so there is no guarantee that a particular
real math function is used in the implementation of a particular
complex function.</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>If you instantiate std::complex for user-defined types, all bets
are off.</p>
<hr>
<h3><a name="447"></a>447. Wrong template argument for time facets</h3>
<p><b>Section:</b> 22.1.1.1.1 [locale.category] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Pete Becker <b>Date:</b> 2003-12-26</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.category">issues</a> in [locale.category].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#327">327</a></p>
<p><b>Discussion:</b></p>
<p>
22.1.1.1.1/4, table 52, "Required Instantiations", lists, among others:
</p>
<pre> time_get<char,InputIterator>
time_get_byname<char,InputIterator>
time_get<wchar_t,OutputIterator>
time_get_byname<wchar_t,OutputIterator>
</pre>
<p>
The second argument to the last two should be InputIterator, not
OutputIterator.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the second template argument to InputIterator.
</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="450"></a>450. set::find is inconsistent with associative container requirements</h3>
<p><b>Section:</b> 23.3.3 [set] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Bill Plauger <b>Date:</b> 2004-01-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#set">issues</a> in [set].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#214">214</a></p>
<p><b>Discussion:</b></p>
<p>map/multimap have:</p>
<pre> iterator find(const key_type& x) const;
const_iterator find(const key_type& x) const;
</pre>
<p>
which is consistent with the table of associative container requirements.
But set/multiset have:
</p>
<pre> iterator find(const key_type&) const;
</pre>
<p>
set/multiset should look like map/multimap, and honor the requirements
table, in this regard.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="451"></a>451. Associative erase should return an iterator</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts], 23.3 [associative] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Bill Plauger <b>Date:</b> 2004-01-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a></p>
<p><b>Discussion:</b></p>
<p>map/multimap/set/multiset have:</p>
<pre> void erase(iterator);
void erase(iterator, iterator);
</pre>
<p>But there's no good reason why these can't return an iterator, as for
vector/deque/list:</p>
<pre> iterator erase(iterator);
iterator erase(iterator, iterator);
</pre>
<p><b>Proposed resolution:</b></p>
<p>
Informally: The table of associative container requirements, and the
relevant template classes, should return an iterator designating the
first element beyond the erased subrange.
</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="452"></a>452. locale::combine should be permitted to generate a named locale</h3>
<p><b>Section:</b> 22.1.1.3 [locale.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Bill Plauger <b>Date:</b> 2004-01-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.members">issues</a> in [locale.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<pre>template<class Facet>
locale::combine(const locale&) const;
</pre>
<p>
is obliged to create a locale that has no name. This is overspecification
and overkill. The resulting locale should follow the usual rules -- it
has a name if the locale argument has a name and Facet is one of the
standard facets.
</p>
<p><i>[
Sydney and post-Sydney (see c++std-lib-13439, c++std-lib-13440,
c++std-lib-13443): agreed that it's overkill to say that the locale
is obligated to be nameless. However, we also can't require it to
have a name. At the moment, locale names are based on categories
and not on individual facets. If a locale contains two different
facets of different names from the same category, then this would
not fit into existing naming schemes. We need to give
implementations more freedom. Bill will provide wording.
]</i></p>
<p><b>Rationale:</b></p>
<p>After further discussion the LWG decided to close this as NAD.
The fundamental problem is that names right now are per-category,
not per-facet. The <tt>combine</tt> member function works at the
wrong level of granularity.</p>
<hr>
<h3><a name="463"></a>463. auto_ptr usability issues</h3>
<p><b>Section:</b> D.9.1 [auto.ptr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Rani Sharoni <b>Date:</b> 2003-12-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#auto.ptr">issues</a> in [auto.ptr].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
TC1 CWG DR #84 effectively made the template<class Y> operator auto_ptr<Y>()
member of auto_ptr (20.4.5.3/4) obsolete.
</p>
<p>
The sole purpose of this obsolete conversion member is to enable copy
initialization base from r-value derived (or any convertible types like
cv-types) case:
</p>
<pre>#include <memory>
using std::auto_ptr;
struct B {};
struct D : B {};
auto_ptr<D> source();
int sink(auto_ptr<B>);
int x1 = sink( source() ); // #1 EDG - no suitable copy constructor
</pre>
<p>
The excellent analysis of conversion operations that was given in the final
auto_ptr proposal
(http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/1997/N1128.pdf)
explicitly specifies this case analysis (case 4). DR #84 makes the analysis
wrong and actually comes to forbid the loophole that was exploited by the
auto_ptr designers.
</p>
<p>
I didn't encounter any compliant compiler (e.g. EDG, GCC, BCC and VC) that
ever allowed this case. This is probably because it requires 3 user defined
conversions and in fact current compilers conform to DR #84.
</p>
<p>
I was surprised to discover that the obsolete conversion member actually has
negative impact of the copy initialization base from l-value derived
case:</p>
<pre>auto_ptr<D> dp;
int x2 = sink(dp); // #2 EDG - more than one user-defined conversion applies
</pre>
<p>
I'm sure that the original intention was allowing this initialization using
the template<class Y> auto_ptr(auto_ptr<Y>& a) constructor (20.4.5.1/4) but
since in this copy initialization it's merely user defined conversion (UDC)
and the obsolete conversion member is UDC with the same rank (for the early
overloading stage) there is an ambiguity between them.
</p>
<p>
Removing the obsolete member will have impact on code that explicitly
invokes it:
</p>
<pre>int y = sink(source().operator auto_ptr<B>());
</pre>
<p>
IMHO no one ever wrote such awkward code and the reasonable workaround for
#1 is:
</p>
<pre>int y = sink( auto_ptr<B>(source()) );
</pre>
<p>
I was even more surprised to find out that after removing the obsolete
conversion member the initialization was still ill-formed:
int x3 = sink(dp); // #3 EDG - no suitable copy constructor
</p>
<p>
This copy initialization semantically requires copy constructor which means
that both template conversion constructor and the auto_ptr_ref conversion
member (20.4.5.3/3) are required which is what was explicitly forbidden in
DR #84. This is a bit amusing case in which removing ambiguity results with
no candidates.
</p>
<p>
I also found exception safety issue with auto_ptr related to auto_ptr_ref:
</p>
<pre>int f(auto_ptr<B>, std::string);
auto_ptr<B> source2();
// string constructor throws while auto_ptr_ref
// "holds" the pointer
int x4 = f(source2(), "xyz"); // #4
</pre>
<p>
The theoretic execution sequence that will cause a leak:
</p>
<ol>
<li>call auto_ptr<B>::operator auto_ptr_ref<B>()</li>
<li>call string::string(char const*) and throw</li>
</ol>
<p>
According to 20.4.5.3/3 and 20.4.5/2 the auto_ptr_ref conversion member
returns auto_ptr_ref<Y> that holds *this and this is another defect since
the type of *this is auto_ptr<X> where X might be different from Y. Several
library vendors (e.g. SGI) implement auto_ptr_ref<Y> with Y* as member which
is much more reasonable. Other vendor implemented auto_ptr_ref as
defectively required and it results with awkward and catastrophic code:
int oops = sink(auto_ptr<B>(source())); // warning recursive on all control
paths
</p>
<p>
Dave Abrahams noticed that there is no specification saying that
auto_ptr_ref copy constructor can't throw.
</p>
<p>
My proposal comes to solve all the above issues and significantly simplify
auto_ptr implementation. One of the fundamental requirements from auto_ptr
is that it can be constructed in an intuitive manner (i.e. like ordinary
pointers) but with strict ownership semantics which yield that source
auto_ptr in initialization must be non-const. My idea is to add additional
constructor template with sole propose to generate ill-formed, diagnostic
required, instance for const auto_ptr arguments during instantiation of
declaration. This special constructor will not be instantiated for other
types which is achievable using 14.8.2/2 (SFINAE). Having this constructor
in hand makes the constructor template<class Y> auto_ptr(auto_ptr<Y> const&)
legitimate since the actual argument can't be const yet non const r-value
are acceptable.
</p>
<p>
This implementation technique makes the "private auxiliary class"
auto_ptr_ref obsolete and I found out that modern C++ compilers (e.g. EDG,
GCC and VC) consume the new implementation as expected and allow all
intuitive initialization and assignment cases while rejecting illegal cases
that involve const auto_ptr arguments.
</p>
<p>The proposed auto_ptr interface:</p>
<pre>namespace std {
template<class X> class auto_ptr {
public:
typedef X element_type;
// 20.4.5.1 construct/copy/destroy:
explicit auto_ptr(X* p=0) throw();
auto_ptr(auto_ptr&) throw();
template<class Y> auto_ptr(auto_ptr<Y> const&) throw();
auto_ptr& operator=(auto_ptr&) throw();
template<class Y> auto_ptr& operator=(auto_ptr<Y>) throw();
~auto_ptr() throw();
// 20.4.5.2 members:
X& operator*() const throw();
X* operator->() const throw();
X* get() const throw();
X* release() throw();
void reset(X* p=0) throw();
private:
template<class U>
auto_ptr(U& rhs, typename
unspecified_error_on_const_auto_ptr<U>::type = 0);
};
}
</pre>
<p>
One compliant technique to implement the unspecified_error_on_const_auto_ptr
helper class is using additional private auto_ptr member class template like
the following:
</p>
<pre>template<typename T> struct unspecified_error_on_const_auto_ptr;
template<typename T>
struct unspecified_error_on_const_auto_ptr<auto_ptr<T> const>
{ typedef typename auto_ptr<T>::const_auto_ptr_is_not_allowed type; };
</pre>
<p>
There are other techniques to implement this helper class that might work
better for different compliers (i.e. better diagnostics) and therefore I
suggest defining its semantic behavior without mandating any specific
implementation. IMO, and I didn't found any compiler that thinks otherwise,
14.7.1/5 doesn't theoretically defeat the suggested technique but I suggest
verifying this with core language experts.
</p>
<p><b>Further changes in standard text:</b></p>
<p>Remove section 20.4.5.3</p>
<p>Change 20.4.5/2 to read something like:
Initializing auto_ptr<X> from const auto_ptr<Y> will result with unspecified
ill-formed declaration that will require unspecified diagnostic.</p>
<p>Change 20.4.5.1/4,5,6 to read:</p>
<pre>template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();</pre>
<p> 4 Requires: Y* can be implicitly converted to X*.</p>
<p> 5 Effects: Calls const_cast<auto_ptr<Y>&>(a).release().</p>
<p> 6 Postconditions: *this holds the pointer returned from a.release().</p>
<p>Change 20.4.5.1/10</p>
<pre>template<class Y> auto_ptr& operator=(auto_ptr<Y> a) throw();
</pre>
<p>
10 Requires: Y* can be implicitly converted to X*. The expression delete
get() is well formed.
</p>
<p>LWG TC DR #127 is obsolete.</p>
<p>
Notice that the copy constructor and copy assignment operator should remain
as before and accept non-const auto_ptr& since they have effect on the form
of the implicitly declared copy constructor and copy assignment operator of
class that contains auto_ptr as member per 12.8/5,10:
</p>
<pre>struct X {
// implicit X(X&)
// implicit X& operator=(X&)
auto_ptr<D> aptr_;
};
</pre>
<p>
In most cases this indicates about sloppy programming but preserves the
current auto_ptr behavior.
</p>
<p>
Dave Abrahams encouraged me to suggest fallback implementation in case that
my suggestion that involves removing of auto_ptr_ref will not be accepted.
In this case removing the obsolete conversion member to auto_ptr<Y> and
20.4.5.3/4,5 is still required in order to eliminate ambiguity in legal
cases. The two constructors that I suggested will co exist with the current
members but will make auto_ptr_ref obsolete in initialization contexts.
auto_ptr_ref will be effective in assignment contexts as suggested in DR
#127 and I can't see any serious exception safety issues in those cases
(although it's possible to synthesize such). auto_ptr_ref<X> semantics will
have to be revised to say that it strictly holds pointer of type X and not
reference to an auto_ptr for the favor of cases in which auto_ptr_ref<Y> is
constructed from auto_ptr<X> in which X is different from Y (i.e. assignment
from r-value derived to base).
</p>
<p><b>Proposed resolution:</b></p>
<p><i>[Redmond: punt for the moment. We haven't decided yet whether we
want to fix auto_ptr for C++-0x, or remove it and replace it with
move_ptr and unique_ptr.]</i></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD. We're just going to deprecate it. It still works for simple use cases
and people know how to deal with it. Going forward <tt>unique_ptr</tt> is the recommended
tool.
</p>
<hr>
<h3><a name="466"></a>466. basic_string ctor should prevent null pointer error</h3>
<p><b>Section:</b> 21.3.1 [string.require] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Daniel Frey <b>Date:</b> 2004-06-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#string.require">issues</a> in [string.require].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Today, my colleagues and me wasted a lot of time. After some time, I
found the problem. It could be reduced to the following short example:
</p>
<pre> #include <string>
int main() { std::string( 0 ); }
</pre>
<p>The problem is that the tested compilers (GCC 2.95.2, GCC 3.3.1 and
Comeau online) compile the above without errors or warnings! The
programs (at least for the GCC) resulted in a SEGV.</p>
<p>I know that the standard explicitly states that the ctor of string
requires a char* which is not zero. STLs could easily detect the above
case with a private ctor for basic_string which takes a single 'int'
argument. This would catch the above code at compile time and would not
ambiguate any other legal ctors.</p>
<p><i>[Redmond: No great enthusiasm for doing this. If we do,
however, we want to do it for all places that take <tt>charT*</tt>
pointers, not just the single-argument constructor. The other
question is whether we want to catch this at compile time (in which
case we catch the error of a literal 0, but not an expression whose
value is a null pointer), at run time, or both.]</i></p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD. Relegate this functionality to debugging implementations.
</p>
<hr>
<h3><a name="470"></a>470. accessing containers from their elements' special functions</h3>
<p><b>Section:</b> 23 [containers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2004-06-28</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#containers">issues</a> in [containers].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The standard doesn't prohibit the destructors (or any other special
functions) of containers' elements invoked from a member function
of the container from "recursively" calling the same (or any other)
member function on the same container object, potentially while the
container is in an intermediate state, or even changing the state
of the container object while it is being modified. This may result
in some surprising (i.e., undefined) behavior.
</p>
<p>Read email thread starting with c++std-lib-13637 for more.</p>
<p><b>Proposed resolution:</b></p>
<p>Add to Container Requirements the following new paragraph:</p>
<pre> Unless otherwise specified, the behavior of a program that
invokes a container member function f from a member function
g of the container's value_type on a container object c that
called g from its mutating member function h, is undefined.
I.e., if v is an element of c, directly or indirectly calling
c.h() from v.g() called from c.f(), is undefined.
</pre>
<p><i>[Redmond: This is a real issue, but it's probably a clause 17
issue, not clause 23. We get the same issue, for example, if we
try to destroy a stream from one of the stream's callback functions.]</i></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD. We agree this is an issue, but not a defect.
We believe that there is no wording we can put in the standard
that will cover all cases without introducing unfortunate
corner cases.
</p>
<hr>
<h3><a name="472"></a>472. Missing "Returns" clause in std::equal_range</h3>
<p><b>Section:</b> 25.3.3.3 [equal.range] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Prateek R Karandikar <b>Date:</b> 2004-06-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#equal.range">issues</a> in [equal.range].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a></p>
<p><b>Discussion:</b></p>
<p>
There is no "Returns:" clause for std::equal_range, which returns non-void.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>Fixed as part of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a>.</p>
<hr>
<h3><a name="476"></a>476. Forward Iterator implied mutability</h3>
<p><b>Section:</b> 24.1.3 [forward.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Dave Abrahams <b>Date:</b> 2004-07-09</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#forward.iterators">issues</a> in [forward.iterators].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>24.1/3 says:</p>
<blockquote><p>
Forward iterators satisfy all the requirements of the input and
output iterators and can be used whenever either kind is specified
</p></blockquote>
<p>
The problem is that satisfying the requirements of output iterator
means that you can always assign *something* into the result of
dereferencing it. That makes almost all non-mutable forward
iterators non-conforming. I think we need to sever the refinement
relationship between forward iterator and output iterator.
</p>
<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#200">200</a>. But this is not a dup.</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>Yes, 24.1/3 does say that. But it's introductory material. The
precise specification is in 24.1.3, and the requrements table there is
right. We don't need to fine-tune introductory wording. (Especially
since this wording is likely to be changed as part of the iterator
overhaul.)</p>
<hr>
<h3><a name="477"></a>477. Operator-> for const forward iterators</h3>
<p><b>Section:</b> 24.1.3 [forward.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dave Abrahams <b>Date:</b> 2004-07-11</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#forward.iterators">issues</a> in [forward.iterators].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a></p>
<p><b>Discussion:</b></p>
<p>
The Forward Iterator requirements table contains the following:
</p>
<pre> expression return type operational precondition
semantics
========== ================== =========== ==========================
a->m U& if X is mutable, (*a).m pre: (*a).m is well-defined.
otherwise const U&
r->m U& (*r).m pre: (*r).m is well-defined.
</pre>
<p>
The first line is exactly right. The second line is wrong. Basically
it implies that the const-ness of the iterator affects the const-ness
of referenced members. But Paragraph 11 of [lib.iterator.requirements] says:
</p>
<blockquote><p>
In the following sections, a and b denote values of type const X, n
denotes a value of the difference type Distance, u, tmp, and m
denote identifiers, r denotes a value of X&, t denotes a value of
value type T, o denotes a value of some type that is writable to
the output iterator.
</p></blockquote>
<p>AFAICT if we need the second line at all, it should read the same
as the first line.</p>
<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a></p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>The LWG agrees that this is a real problem. Marked as a DUP
because the LWG chose to adopt the solution proposed in
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>.
</p>
<hr>
<h3><a name="479"></a>479. Container requirements and placement new</h3>
<p><b>Section:</b> 23.1 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Herb Sutter <b>Date:</b> 2004-08-01</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements">active issues</a> in [container.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements">issues</a> in [container.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#580">580</a></p>
<p><b>Discussion:</b></p>
<p>Nothing in the standard appears to make this program ill-formed:</p>
<pre> struct C {
void* operator new( size_t s ) { return ::operator new( s ); }
// NOTE: this hides in-place and nothrow new
};
int main() {
vector<C> v;
v.push_back( C() );
}
</pre>
<p>Is that intentional? We should clarify whether or not we intended
to require containers to support types that define their own special
versions of <tt>operator new</tt>.</p>
<p><i>[
Lillehammer: A container will definitely never use this overridden
operator new, but whether it will fail to compile is unclear from the
standard. Are containers supposed to use qualified or unqualified
placement new? 20.4.1.1 is somewhat relevant, but the standard
doesn't make it completely clear whether containers have to use
Allocator::construct(). If containers don't use it, the details of how
containers use placement new are unspecified. That is the real bug,
but it needs to be fixed as part of the allocator overhaul. Weak
support that the eventual solution should make this code well formed.
]</i></p>
<p><b>Proposed resolution:</b></p>
<hr>
<h3><a name="480"></a>480. unary_function and binary_function should have protected nonvirtual destructors</h3>
<p><b>Section:</b> 20.5.3 [base] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Joe Gottman <b>Date:</b> 2004-08-19</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#base">issues</a> in [base].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>The classes std::unary_function and std::binary_function are both
designed to be inherited from but contain no virtual functions. This
makes it too easy for a novice programmer to write code like
binary_function<int, int, int> *p = new plus<int>; delete p;</p>
<p>There are two common ways to prevent this source of undefined
behavior: give the base class a public virtual destructor, or give it
a protected nonvirtual destructor. Since unary_function and
binary_function have no other virtual functions, (note in particular
the absence of an operator()() ), it would cost too much to give them
public virtual destructors. Therefore, they should be given protected
nonvirtual destructors.</p>
<p><b>Proposed resolution:</b></p>
<p>Change Paragraph 20.3.1 of the Standard from</p>
<pre> template <class Arg, class Result>
struct unary_function {
typedef Arg argument_type;
typedef Result result_type;
};
template <class Arg1, class Arg2, class Result>
struct binary_function {
typedef Arg1 first_argument_type;
typedef Arg2 second_argument_type;
typedef Result result_type;
};
</pre>
<p>to</p>
<pre> template <class Arg, class Result>
struct unary_function {
typedef Arg argument_type;
typedef Result result_type;
protected:
~unary_function() {}
};
template <class Arg1, class Arg2, class Result>
struct binary_function {
typedef Arg1 first_argument_type;
typedef Arg2 second_argument_type;
typedef Result result_type;
protected:
~binary_function() {}
};
</pre>
<p><b>Rationale:</b></p>
<p>The LWG doesn't believe the existing definition causes anybody any
concrete harm.</p>
<hr>
<h3><a name="481"></a>481. unique's effects on the range [result, last)</h3>
<p><b>Section:</b> 25.2.9 [alg.unique] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Andrew Koenig <b>Date:</b> 2004-08-30</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.unique">issues</a> in [alg.unique].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The standard says that unique(first, last) "eliminates all but the
first element from every consecutive group of equal elements" in
[first, last) and returns "the end of the resulting range". So a
postcondition is that [first, result) is the same as the old [first,
last) except that duplicates have been eliminated.
</p>
<p>What postconditions are there on the range [result, last)? One
might argue that the standard says nothing about those values, so
they can be anything. One might also argue that the standard
doesn't permit those values to be changed, so they must not be.
Should the standard say something explicit one way or the other?</p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<p><b>Rationale:</b></p>
<p>We don't want to make many guarantees about what's in [result,
end). Maybe we aren't being quite explicit enough about not being
explicit, but it's hard to think that's a major problem.</p>
<hr>
<h3><a name="482"></a>482. Swapping pairs</h3>
<p><b>Section:</b> 20.2.3 [pairs], 20.3 [tuple] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Andrew Koenig <b>Date:</b> 2004-09-14</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>(Based on recent comp.std.c++ discussion)</p>
<p>Pair (and tuple) should specialize std::swap to work in terms of
std::swap on their components. For example, there's no obvious reason
why swapping two objects of type pair<vector<int>,
list<double> > should not take O(1).</p>
<p><i>[Lillehammer: We agree it should be swappable. Howard will
provide wording.]</i></p>
<p><i>[
Post Oxford: We got <tt>swap</tt> for <tt>pair</tt> but accidently
missed <tt>tuple</tt>. <tt>tuple::swap</tt> is being tracked by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#522">522</a>.
]</i></p>
<p><b>Proposed resolution:</b></p>
<p>
Wording provided in
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1856.html#20.2.3%20-%20Pairs">N1856</a>.
</p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD, fixed by
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1856.html#20.2.3%20-%20Pairs">N1856</a>.
</p>
<hr>
<h3><a name="483"></a>483. Heterogeneous equality and EqualityComparable</h3>
<p><b>Section:</b> 25.1 [alg.nonmodifying], 25.2 [alg.modifying.operations] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Peter Dimov <b>Date:</b> 2004-09-20</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#283">283</a></p>
<p><b>Discussion:</b></p>
<p>c++std-lib-14262</p>
<p>[lib.alg.find] requires T to be EqualityComparable:</p>
<pre>template <class InputIterator, class T>
InputIterator find(InputIterator first, InputIterator last,
const T& value);
</pre>
<p>
However the condition being tested, as specified in the Effects
clause, is actually *i == value, where i is an InputIterator.
</p>
<p>
The two clauses are in agreement only if the type of *i is T, but this
isn't necessarily the case. *i may have a heterogeneous comparison
operator that takes a T, or a T may be convertible to the type of *i.
</p>
<p>Further discussion (c++std-lib-14264): this problem affects a
number of algorithsm in clause 25, not just <tt>find</tt>. We
should try to resolve this problem everywhere it appears.</p>
<p><b>Proposed resolution:</b></p>
<p>[lib.alg.find]:</p>
<blockquote><p>
Remove [lib.alg.find]/1.
</p></blockquote>
<p>[lib.alg.count]:</p>
<blockquote><p>
Remove [lib.alg.count]/1.
</p></blockquote>
<p>[lib.alg.search]:</p>
<blockquote><p>
Remove "Type T is EqualityComparable (20.1.1), " from [lib.alg.search]/4.
</p></blockquote>
<p>[lib.alg.replace]:</p>
<blockquote>
<p>
Remove [lib.alg.replace]/1.
Replace [lb.alg.replace]/2 with:
</p>
<blockquote><p>
For every iterator i in the range [first, last) for which *i == value
or pred(*i) holds perform *i = new_value.
</p></blockquote>
<p>
Remove the first sentence of /4.
Replace the beginning of /5 with:
</p>
<blockquote><p>
For every iterator i in the range [result, result + (last -
first)), assign to *i either...
</p></blockquote>
<p>(Note the defect here, current text says assign to i, not *i).</p>
</blockquote>
<p>[lib.alg.fill]:</p>
<blockquote>
<p>
Remove "Type T is Assignable (23.1), " from /1.
Replace /2 with:
</p>
<blockquote><p>
For every iterator i in the range [first, last) or [first, first + n),
perform *i = value.
</p></blockquote>
</blockquote>
<p>[lib.alg.remove]:</p>
<blockquote><p>
Remove /1.
Remove the first sentence of /6.
</p></blockquote>
<p><b>Rationale:</b></p>
<p>Duplicate of (a subset of) issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#283">283</a>.</p>
<hr>
<h3><a name="486"></a>486. min/max CopyConstructible requirement is too strict</h3>
<p><b>Section:</b> 25.3.7 [alg.min.max] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Dave Abrahams <b>Date:</b> 2004-10-13</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.min.max">issues</a> in [alg.min.max].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#281">281</a></p>
<p><b>Discussion:</b></p>
<p>A straightforward implementation of these algorithms does not need to
copy T.</p>
<p><b>Proposed resolution:</b></p>
<p>drop the the words "and CopyConstructible" from paragraphs 1 and 4</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="487"></a>487. Allocator::construct is too limiting</h3>
<p><b>Section:</b> 20.1.2 [allocator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Dhruv Matani <b>Date:</b> 2004-10-17</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#allocator.requirements">active issues</a> in [allocator.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#allocator.requirements">issues</a> in [allocator.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The standard's version of allocator::construct(pointer,
const_reference) severely limits what you can construct using this
function. Say you can construct a socket from a file descriptor. Now,
using this syntax, I first have to manually construct a socket from
the fd, and then pass the constructed socket to the construct()
function so it will just to an uninitialized copy of the socket I
manually constructed. Now it may not always be possible to copy
construct a socket eh! So, I feel that the changes should go in the
allocator::construct(), making it:
</p>
<pre> template<typename T>
struct allocator{
template<typename T1>
void construct(pointer T1 const& rt1);
};
</pre>
<p>
Now, the ctor of the class T which matches the one that takes a T1 can
be called! Doesn't that sound great?
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>NAD. STL uses copying all the time, and making it possible for
allocators to construct noncopyable objects is useless in the
absence of corresponding container changes. We might consider this
as part of a larger redesign of STL.</p>
<hr>
<h3><a name="489"></a>489. std::remove / std::remove_if wrongly specified</h3>
<p><b>Section:</b> 25.2.8 [alg.remove] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Thomas Mang <b>Date:</b> 2004-12-12</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.remove">issues</a> in [alg.remove].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In Section 25.2.7 [lib.alg.remove], paragraphs 1 to 5 describe the
behavior of the mutating sequence operations std::remove and
std::remove_if. However, the wording does not reflect the intended
behavior [Note: See definition of intended behavior below] of these
algorithms, as it is known to the C++ community [1].
</p>
<p>1) Analysis of current wording:</p>
<p>25.2.7 [lib.alg.remove], paragraph 2:</p>
<p>Current wording says:
"Effects: Eliminates all the elements referred to by iterator i in the
range [first, last) for which the following corresponding conditions
hold: *i == value, pred(*i) != false."</p>
<p>
This sentences expresses specifically that all elements denoted by the
(original) range [first, last) for which the corresponding condition
hold will be eliminated. Since there is no formal definition of the term
"eliminate" provided, the meaning of "eliminate" in everyday language
implies that as postcondition, no element in the range denoted by
[first, last) will hold the corresponding condition on reiteration over
the range [first, last).
</p>
<p>
However, this is neither the intent [Note: See definition of intended
behavior below] nor a general possible approach. It can be easily proven
that if all elements of the original range[first, last) will hold the
condition, it is not possible to substitute them by an element for which
the condition will not hold.
</p>
<p>25.2.7 [lib.alg.remove], paragraph 3:</p>
<p>
Current wording says:
"Returns: The end of the resulting range."
</p>
<p>
The resulting range is not specified. In combination with 25.2.7
[lib.alg.remove], paragraph 2, the only reasonable interpretation of
this so-called resulting range is the range [first,last) - thus
returning always the ForwardIterator 'last' parameter.
</p>
<p>
25.2.7 [lib.alg.remove], paragraph 4:
</p>
<p>
Current wording says:
"Notes: Stable: the relative order of the elements that are not removed
is the same as their relative order in the original range"
</p>
<p>
This sentences makes use of the term "removed", which is neither
specified, nor used in a previous paragraph (which uses the term
"eliminate"), nor unamgiuously separated from the name of the algorithm.
</p>
<p>2) Description of intended behavior:</p>
<p>
For the rest of this Defect Report, it is assumed that the intended
behavior was that all elements of the range [first, last) which do not
hold the condition *i == value (std::remove) or pred(*i) != false
(std::remove_if)], call them s-elements [Note: s...stay], will be placed
into a contiguous subrange of [first, last), denoted by the iterators
[first, return value). The number of elements in the resulting range
[first, return value) shall be equal to the number of s-elements in the
original range [first, last). The relative order of the elements in the
resulting subrange[first, return value) shall be the same as the
relative order of the corresponding elements in the original range. It
is undefined whether any elements in the resulting subrange [return
value, last) will hold the corresponding condition, or not.
</p>
<p>
All implementations known to the author of this Defect Report comply
with this intent. Since the intent of the behavior (contrary to the
current wording) is also described in various utility references serving
the C++ community [1], it is not expected that fixing the paragraphs
will influence current code - unless the code relies on the behavior as
it is described by current wording and the implementation indeed
reflects the current wording, and not the intent.
</p>
<p>3) Proposed fixes:</p>
<p>Change 25.2.7 [lib.alg.remove], paragraph 2 to:</p>
<p>
"Effect: Places all the elements referred to by iterator i in the range
[first, last) for which the following corresponding conditions hold :
!(*i == value), pred(*i) == false into the subrange [first, k) of the
original range, where k shall denote a value of type ForwardIterator. It
is undefined whether any elements in the resulting subrange [k, last)
will hold the corresponding condition, or not."
</p>
<p>Comments to the new wording:</p>
<p>
a) "Places" has no special meaning, and the everyday language meaning
should fit.
b) The corresponding conditions were negated compared to the current
wording, becaue the new wording requires it.
c) The wording "of the original range" might be redundant, since any
subrange starting at 'first' and containing no more elements than the
original range is implicitly a subrange of the original range [first,
last).
d) The iterator k was introduced instead of "return value" in order to
avoid a cyclic dependency on 25.2.7/3. The wording ", where k shall
denote a value of type ForwardIterator" might be redundant, because it
follows implicitly by 25.2.7/3.
e) "Places" does, in the author's opinion, explicitly forbid duplicating
any element holding the corresponding condition in the original range
[first, last) within the resulting range [first, k). If there is doubt
this term might be not unambiguous regarding this, it is suggested that
k is specified more closely by the following wording: "k shall denote a
value of type ForwardIterator [Note: see d)] so that k - first is equal
to the number of elements in the original range [first, last) for which
the corresponding condition did hold". This could also be expressed as a
separate paragraph "Postcondition:"
f) The senctence "It is undefined whether any elements in the resulting
subrange [k, last) will hold the corresponding condition, or not." was
added consciously so the term "Places" does not imply if the original
range [first, last) contains n elements holding the corresponding
condition, the identical range[first, last) will also contain exactly n
elements holding the corresponding condition after application of the
algorithm.
</p>
<p>
Change 25.2.7 [lib.alg.remove], paragraph 3 to:
"Returns: The iterator k."
</p>
<p>
Change 25.2.7 [lib.alg.remove], paragraph 4 to:
"Notes: Stable: the relative order of the elements that are placed into
the subrange [first, return value) shall be the same as their relative
order was in the original range [first, last) prior to application of
the algorithm."
</p>
<p>
Comments to the new wording:
</p>
<p>
a) the wording "was ... prior to application of the algorithm" is used
to explicitly distinguish the original range not only by means of
iterators, but also by a 'chronological' factor from the resulting range
[first, return value). It might be redundant.
</p>
<p>
[1]:
The wording of these references is not always unambiguous, and provided
examples partially contradict verbal description of the algorithms,
because the verbal description resembles the problematic wording of
ISO/IEC 14882:2003.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>The LWG believes that the standard is sufficiently clear, and that
there is no evidence of any real-world confusion about this point.</p>
<hr>
<h3><a name="490"></a>490. std::unique wrongly specified</h3>
<p><b>Section:</b> 25.2.9 [alg.unique] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Thomas Mang <b>Date:</b> 2004-12-12</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.unique">issues</a> in [alg.unique].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In Section 25.2.8 [lib.alg.unique], paragraphs 1 to 3 describe the
behavior of the mutating sequence operation std::unique. However, the
wording does not reflect the intended behavior [Note: See definition of
intended behavior below] of these algorithms, as it is known to the C++
community [1].</p>
<p>1) Analysis of current wording:</p>
<p>25.2.8 [lib.alg.unique], paragraph 1:</p>
<p>
Current wording says:
"Effects: Eliminates all but the first element from every consecutive
group of equal elements referred to by the iterator i in the range
[first, last) for which the following corresponding conditions hold: *i
== *(i - 1) or pred(*i, *(i -1)) != false"
</p>
<p>
This sentences expresses specifically that all elements denoted by the
(original) range [first, last) which are not but the first element from
a consecutive group of equal elements (where equality is defined as *i
== *(i - 1) or pred(*i, *(i - 1)) ! = false) [Note: See DR 202], call
them r-elements [Note: r...remove], will be eliminated. Since there is
no formal definition of the term "eliminate" provided, it is undefined
how this "elimination" takes place. But the meaning of "eliminate" in
everyday language seems to disallow explicitly that after application of
the algorithm, any r-element will remain at any position of the range
[first, last) [2].
</p>
<p>
Another defect in the current wording concerns the iterators used to
compare two elements for equality: The current wording contains the
expression "(i - 1)", which is not covered by 25/9 [Note: See DR
submitted by Thomas Mang regarding invalid iterator arithmetic
expressions].
</p>
<p>
25.2.8 [lib.alg.unique], paragraph 2:
</p>
<p>Current wording says:
"Returns: The end of the resulting range."</p>
<p>
The resulting range is not specified. In combination with 25.2.8
[lib.alg.unique], paragraph 1, one reasonable interpretation (in the
author's opinion even the only possible interpretation) of this
so-called resulting range is the range [first, last) - thus returning
always the ForwardIterator 'last' parameter.
</p>
<p>2) Description of intended behavior:</p>
<p>
For the rest of this Defect Report, it is assumed that the intended
behavior was that all elements denoted by the original range [first,
last) which are the first element from a consecutive group of elements
for which the corresponding conditions: *(i-1) == *i (for the version of
unique without a predicate argument) or pred(*(i-1), *i) ! = false (for
the version of unique with a predicate argument) [Note: If such a group
of elements consists of only a single element, this is also considered
the first element] [Note: See resolutions of DR 202], call them
s-elements [Note: s...stay], will be placed into a contiguous subrange
of [first, last), denoted by the iterators [first, return value). The
number of elements in the resulting range [first, return value) shall be
equal to the number of s-elements in the original range [first, last).
Invalid iterator arithmetic expressions are expected to be resolved as
proposed in DR submitted by Thomas Mang regarding invalid iterator
arithmetic expressions. It is also assumed by the author that the
relative order of the elements in the resulting subrange [first, return
value) shall be the same as the relative order of the corresponding
elements (the s-elements) in the original range [Note: If this was not
intended behavior, the additional proposed paragraph about stable order
will certainly become obsolete].
Furthermore, the resolutions of DR 202 are partially considered.
</p>
<p>
All implementations known to the author of this Defect Report comply
with this intent [Note: Except possible effects of DR 202]. Since this
intent of the behavior (contrary to the current wording) is also
described in various utility references serving the C++ community [1],
it is not expected that fixing the paragraphs will influence current
code [Note: Except possible effects of DR 202] - unless the code relies
on the behavior as it is described by current wording and the
implementation indeed reflects the current wording, and not the intent.
</p>
<p>3) Proposed fixes:</p>
<p>
Change 25.2.8 [lib.alg.unique], paragraph 1 to:
</p>
<p>
"Effect: Places the first element from every consecutive group of
elements, referred to by the iterator i in the range [first, last), for
which the following conditions hold: *(i-1) == *i (for the version of
unique without a predicate argument) or pred(*(i -1), *i) != false (for
the version of unique with a predicate argument), into the subrange
[first, k) of the original range, where k shall denote a value of type
ForwardIterator."
</p>
<p>Comments to the new wording:</p>
<p>
a) The new wording was influenced by the resolutions of DR 202. If DR
202 is resolved in another way, the proposed wording need also
additional review.
b) "Places" has no special meaning, and the everyday language meaning
should fit.
c) The expression "(i - 1)" was left, but is expected that DR submitted
by Thomas Mang regarding invalid iterator arithmetic expressions will
take this into account.
d) The wording "(for the version of unique without a predicate
argument)" and "(for the version of unique with a predicate argument)"
was added consciously for clarity and is in resemblence with current
23.2.2.4 [lib.list.ops], paragraph 19. It might be considered redundant.
e) The wording "of the original range" might be redundant, since any
subrange starting at first and containing no more elements than the
original range is implicitly a subrange of the original range [first,
last).
f) The iterator k was introduced instead of "return value" in order to
avoid a cyclic dependency on 25.2.8 [lib.alg.unique], paragraph 2. The
wording ", where k shall denote a value of type ForwardIterator" might
be redundant, because it follows implicitly by 25.2.8 [lib.alg.unique],
paragraph 2.
g) "Places" does, in the author's opinion, explicitly forbid duplicating
any s-element in the original range [first, last) within the resulting
range [first, k). If there is doubt this term might be not unambiguous
regarding this, it is suggested that k is specified more closely by the
following wording: "k shall denote a value of type ForwardIterator
[Note: See f)] so that k - first is equal to the number of elements in
the original range [first, last) being the first element from every
consecutive group of elements for which the corresponding condition did
hold". This could also be expressed as a separate paragraph
"Postcondition:".
h) If it is considered that the wording is unclear whether it declares
the element of a group which consists of only a single element
implicitly to be the first element of this group [Note: Such an
interpretation could eventually arise especially in case last - first ==
1] , the following additional sentence is proposed: "If such a group of
elements consists of only a single element, this element is also
considered the first element."
</p>
<p>
Change 25.2.8 [lib.alg.unique], paragraph 2 to:
"Returns: The iterator k."
</p>
<p>
Add a separate paragraph "Notes:" as 25.2.8 [lib.alg.unique], paragraph
2a or 3a, or a separate paragraph "Postcondition:" before 25.2.8
[lib.alg.unique], paragraph 2 (wording inside {} shall be eliminated if
the preceding expressions are used, or the preceding expressions shall
be eliminated if wording inside {} is used):
</p>
<p>
"Notes:{Postcondition:} Stable: the relative order of the elements that
are placed into the subrange [first, return value {k}) shall be the same
as their relative order was in the original range [first, last) prior to
application of the algorithm."
</p>
<p>Comments to the new wording:</p>
<p>
a) It is assumed by the author that the algorithm was intended to be
stable.
In case this was not the intent, this paragraph becomes certainly
obsolete.
b) The wording "was ... prior to application of the algorithm" is used
to explicitly distinguish the original range not only by means of
iterators, but also by a 'chronological' factor from the resulting range
[first, return value). It might be redundant.
</p>
<p>
25.2.8 [lib.alg.unique], paragraph 3:
</p>
<p>See DR 239.</p>
<p>
4) References to other DRs:
</p>
<p>
See DR 202, but which does not address any of the problems described in
this Defect Report [Note: This DR is supposed to complement DR 202].
See DR 239.
See DR submitted by Thomas Mang regarding invalid iterator arithmetic
expressions.
</p>
<p>
[1]:
The wording of these references is not always unambiguous, and provided
examples partially contradict verbal description of the algorithms,
because the verbal description resembles the problematic wording of
ISO/IEC 14882:2003.
</p>
<p>
[2]:
Illustration of conforming implementations according to current wording:
</p>
<p>
One way the author of this DR considers how this "elimination" could be
achieved by a conforming implementation according to current wording is
by substituting each r-element by _any_ s-element [Note: s...stay; any
non-r-element], since all r-elements are "eliminated".
</p>
<p>
In case of a sequence consisting of elements being all 'equal' [Note:
See DR 202], substituting each r-element by the single s-element is the
only possible solution according to current wording.
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>The LWG believes the standard is sufficiently clear. No
implementers get it wrong, and changing it wouldn't cause any code to
change, so there is no real-world harm here.</p>
<hr>
<h3><a name="491"></a>491. std::list<>::unique incorrectly specified</h3>
<p><b>Section:</b> 23.2.3.4 [list.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Thomas Mang <b>Date:</b> 2004-12-12</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#list.ops">issues</a> in [list.ops].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>In Section 23.2.3.4 [list.ops], paragraphs 19 to 21 describe the
behavior of the std::list<T, Allocator>::unique operation. However, the
current wording is defective for various reasons.</p>
<p>
1) Analysis of current wording:
</p>
<p>23.2.3.4 [list.ops], paragraph 19:</p>
<p>
Current wording says:
"Effects: Eliminates all but the first element from every consecutive
group of equal elements referred to by the iterator i in the range
[first + 1, last) for which *i == *(i - 1) (for the version of unique
with no argument) or pred(*i, *(i -1)) (for the version of unique with a
predicate argument) holds."</p>
<p>
This sentences makes use of the undefined term "Eliminates". Although it
is, to a certain degree, reasonable to consider the term "eliminate"
synonymous with "erase", using "Erase" in the first place, as the
wording of 23.2.3.4 [list.ops], paragraph 15 does, would be clearer.</p>
<p>
The range of the elements referred to by iterator i is "[first + 1,
last)". However, neither "first" nor "last" is defined.</p>
<p>
The sentence makes three times use of iterator arithmetic expressions (
"first + 1", "*i == *(i - 1)", "pred(*i, *(i -1))" ) which is not
defined for bidirectional iterator [see DR submitted by Thomas Mang
regarding invalid iterator arithmetic expressions].</p>
<p>
The same problems as pointed out in DR 202 (equivalence relation / order
of arguments for pred()) apply to this paragraph.</p>
<p>
23.2.3.4 [list.ops], paragraph 20:
</p>
<p>
Current wording says:
"Throws: Nothing unless an exception in thrown by *i == *(i-1) or
pred(*i, *(i - 1))"</p>
<p>
The sentence makes two times use of invalid iterator arithmetic
expressions ( "*i == *(i - 1)", "pred(*i, *(i -1))" ).
</p>
<p>
[Note: Minor typos: "in" / missing dot at end of sentence.]
</p>
<p>
23.2.3.4 [list.ops], paragraph 21:</p>
<p>
Current wording says:
"Complexity: If the range (last - first) is not empty, exactly (last -
first) - 1 applications of the corresponding predicate, otherwise no
application of the predicate.</p>
<p>
See DR 315 regarding "(last - first)" not yielding a range.</p>
<p>
Invalid iterator arithmetic expression "(last - first) - 1" left .</p>
<p>2) Description of intended behavior:</p>
<p>
For the rest of this Defect Report, it is assumed that "eliminate" is
supposed to be synonymous to "erase", that "first" is equivalent to an
iterator obtained by a call to begin(), "last" is equivalent to an
iterator obtained by a call to end(), and that all invalid iterator
arithmetic expressions are resolved as described in DR submitted by
Thomas Mang regarding invalid iterator arithmetic expressions.</p>
<p>
Furthermore, the resolutions of DR 202 are considered regarding
equivalence relation and order of arguments for a call to pred.</p>
<p>
All implementations known to the author of this Defect Report comply
with these assumptions, apart from the impact of the alternative
resolution of DR 202. Except for the changes implied by the resolutions
of DR 202, no impact on current code is expected.</p>
<p>
3) Proposed fixes:</p>
<p>
Change 23.2.3.4 [list.ops], paragraph 19 to:</p>
<p>
"Effect: Erases all but the first element from every consecutive group
of elements, referred to by the iterator i in the range [begin(),
end()), for which the following conditions hold: *(i-1) == *i (for the
version of unique with no argument) or pred(*(i-1), *i) != false (for
the version of unique with a predicate argument)."</p>
<p>
Comments to the new wording:</p>
<p>
a) The new wording was influenced by DR 202 and the resolutions
presented there. If DR 202 is resolved in another way, the proposed
wording need also additional review.
b) "Erases" refers in the author's opinion unambiguously to the member
function "erase". In case there is doubt this might not be unamgibuous,
a direct reference to the member function "erase" is suggested [Note:
This would also imply a change of 23.2.3.4 [list.ops], paragraph
15.].
c) The expression "(i - 1)" was left, but is expected that DR submitted
by Thomas Mang regarding invalid iterator arithmetic expressions will
take this into account.
d) The wording "(for the version of unique with no argument)" and "(for
the version of unique with a predicate argument)" was kept consciously
for clarity.
e) "begin()" substitutes "first", and "end()" substitutes "last". The
range need adjustment from "[first + 1, last)" to "[begin(), end())" to
ensure a valid range in case of an empty list.
f) If it is considered that the wording is unclear whether it declares
the element of a group which consists of only a single element
implicitly to be the first element of this group [Note: Such an
interpretation could eventually arise especially in case size() == 1] ,
the following additional sentence is proposed: "If such a group of
elements consists of only a single element, this element is also
considered the first element."</p>
<p>
Change 23.2.3.4 [list.ops], paragraph 20 to:</p>
<p>
"Throws: Nothing unless an exception is thrown by *(i-1) == *i or
pred(*(i-1), *i)."</p>
<p>
Comments to the new wording:</p>
<p>
a) The wording regarding the conditions is identical to proposed
23.2.3.4 [list.ops], paragraph 19. If 23.2.3.4 [list.ops],
paragraph 19 is resolved in another way, the proposed wording need also
additional review.
b) The expression "(i - 1)" was left, but is expected that DR submitted
by Thomas Mang regarding invalid iterator arithmetic expressions will
take this into account.
c) Typos fixed.</p>
<p>
Change 23.2.3.4 [list.ops], paragraph 21 to:</p>
<p>
"Complexity: If empty() == false, exactly size() - 1 applications of the
corresponding predicate, otherwise no applications of the corresponding
predicate."</p>
<p>
Comments to the new wording:</p>
<p>
a) The new wording is supposed to also replace the proposed resolution
of DR 315, which suffers from the problem of undefined "first" / "last".
</p>
<p>
5) References to other DRs:</p>
<p>See DR 202.
See DR 239.
See DR 315.
See DR submitted by Thomas Mang regarding invalid iterator arithmetic
expressions.</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>"All implementations known to the author of this Defect Report
comply with these assumption", and "no impact on current code is
expected", i.e. there is no evidence of real-world confusion or
harm.</p>
<hr>
<h3><a name="493"></a>493. Undefined Expression in Input Iterator Note Title</h3>
<p><b>Section:</b> 24.1.1 [input.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Chris Jefferson <b>Date:</b> 2004-12-13</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#input.iterators">issues</a> in [input.iterators].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>1) In 24.1.1/3, the following text is currently present.</p>
<p>"Note: For input iterators, a==b does not imply ++a=++b (Equality does
not guarantee the substitution property or referential transparency)."</p>
<p>However, when in Table 72, part of the definition of ++r is given as:</p>
<p>"pre: r is dereferenceable.
post: any copies of the previous value of r are no longer required
either to be dereferenceable ..."</p>
<p>While a==b does not imply that b is a copy of a, this statement should
perhaps still be made more clear.</p>
<p>2) There are no changes to intended behaviour</p>
<p>
3) This Note should be altered to say "Note: For input iterators a==b,
when its behaviour is defined ++a==++b may still be false (Equality does
not guarantee the substitution property or referential transparency).</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>This is descriptive text, not normative, and the meaning is clear.</p>
<hr>
<h3><a name="494"></a>494. Wrong runtime complexity for associative container's insert and delete</h3>
<p><b>Section:</b> 23.1.2 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Hans B os <b>Date:</b> 2004-12-19</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>According to [lib.associative.reqmts] table 69, the runtime comlexity
of insert(p, t) and erase(q) can be done in amortized constant time.</p>
<p>It was my understanding that an associative container could be
implemented as a balanced binary tree.</p>
<p>For inser(p, t), you 'll have to iterate to p's next node to see if t
can be placed next to p. Furthermore, the insertion usually takes
place at leaf nodes. An insert next to the root node will be done at
the left of the root next node</p>
<p>So when p is the root node you 'll have to iterate from the root to
its next node, which takes O(log(size)) time in a balanced tree.</p>
<p>If you insert all values with insert(root, t) (where root is the
root of the tree before insertion) then each insert takes O(log(size))
time. The amortized complexity per insertion will be O(log(size))
also.</p>
<p>For erase(q), the normal algorithm for deleting a node that has no
empty left or right subtree, is to iterate to the next (or previous),
which is a leaf node. Then exchange the node with the next and delete
the leaf node. Furthermore according to DR 130, erase should return
the next node of the node erased. Thus erasing the root node,
requires iterating to the next node.</p>
<p>Now if you empty a map by deleting the root node until the map is
empty, each operation will take O(log(size)), and the amortized
complexity is still O(log(size)).</p>
<p>The operations can be done in amortized constant time if iterating
to the next node can be done in (non amortized) constant time. This
can be done by putting all nodes in a double linked list. This
requires two extra links per node. To me this is a bit overkill since
you can already efficiently insert or erase ranges with erase(first,
last) and insert(first, last).</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>Only "amortized constant" in special circumstances, and we believe
that's implementable. That is: doing this N times will be O(N), not
O(log N).</p>
<hr>
<h3><a name="499"></a>499. Std. doesn't seem to require stable_sort() to be stable!</h3>
<p><b>Section:</b> 25.3.1.2 [stable.sort] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Prateek Karandikar <b>Date:</b> 2005-04-12</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<blockquote><p>
17.3.1.1 Summary</p>
<p>
1 The Summary provides a synopsis of the category, and introduces the
first-level subclauses. Each subclause also provides a summary, listing
the headers specified in the subclause and the library entities
provided in each header.
</p>
<p>
2 Paragraphs labelled "Note(s):" or "Example(s):" are informative,
other paragraphs are normative.
</p></blockquote>
<p>So this means that a "Notes" paragraph wouldn't be normative. </p>
<blockquote><p>
25.3.1.2 stable_sort
</p>
<pre>template<class RandomAccessIterator>
void stable_sort(RandomAccessIterat or first, RandomAccessIterator last);
template<class RandomAccessIterator, class Compare>
void stable_sort(RandomAccessIterat or first, RandomAccessIterator last, Compare comp);
</pre>
<p>
1 Effects: Sorts the elements in the range [first, last).
</p>
<p>
2 Complexity: It does at most N(log N)^2 (where N == last - first)
comparisons; if enough extra memory is available, it is N log N.
</p>
<p>
3 Notes: Stable: the relative order of the equivalent elements is
preserved.
</p></blockquote>
<p>
The Notes para is informative, and nowhere else is stability mentioned above.
</p>
<p>
Also, I just searched for the word "stable" in my copy of the Standard.
and the phrase "Notes: Stable: the relative order of the elements..."
is repeated several times in the Standard library clauses for
describing various functions. How is it that stability is talked about
in the informative paragraph? Or am I missing something obvious?
</p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<p><b>Rationale:</b></p>
<p>
This change has already been made.
</p>
<hr>
<h3><a name="500"></a>500. do_length cannot be implemented correctly</h3>
<p><b>Section:</b> 22.2.1.5 [locale.codecvt.byname] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Krzysztof Żelechowski <b>Date:</b> 2005-05-24</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.codecvt.byname">issues</a> in [locale.codecvt.byname].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<ol>
<li>codecvt::do_length is of type int;</li>
<li>it is assumed to be sort-of returning from_next - from of type ptrdiff_t;</li>
<li>ptrdiff_t cannot be cast to an int without data loss.</li>
</ol>
<p>
Contradiction.
</p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<hr>
<h3><a name="501"></a>501. Proposal: strengthen guarantees of lib.comparisons</h3>
<p><b>Section:</b> 20.5.3 [base] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Me <anti_spam_email2003@yahoo.com> <b>Date:</b> 2005-06-07</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#base">issues</a> in [base].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<blockquote><p>
"For templates greater, less, greater_equal, and less_equal,
the specializations for any pointer type yield a total order, even if
the built-in operators <, >, <=, >= do not."
</p></blockquote>
<p>
The standard should do much better than guarantee that these provide a
total order, it should guarantee that it can be used to test if memory
overlaps, i.e. write a portable memmove. You can imagine a platform
where the built-in operators use a uint32_t comparison (this tests for
overlap on this platform) but the less<T*> functor is allowed to be
defined to use a int32_t comparison. On this platform, if you use
std::less with the intent of making a portable memmove, comparison on
an array that straddles the 0x7FFFFFFF/0x8000000 boundary can give
incorrect results.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add a footnote to 20.5.3/8 saying:
</p>
<blockquote><p>
Given a p1 and p2 such that p1 points to N objects of type T and p2
points to M objects of type T. If [p1,p1+N) does not overlap [p2,p2+M),
less returns the same value when comparing all pointers in [p1,p1+N) to
all pointers in [p2,p2+M). Otherwise, there is a value Q and a value R
such that less returns the same value when comparing all pointers in
[p1,p1+Q) to all pointers in [p2,p2+R) and an opposite value when
comparing all pointers in [p1+Q,p1+N) to all pointers in [p2+R,p2+M).
For the sake of completeness, the null pointer value (4.10) for T is
considered to be an array of 1 object that doesn't overlap with any
non-null pointer to T. less_equal, greater, greater_equal, equal_to,
and not_equal_to give the expected results based on the total ordering
semantics of less. For T of void, treat it as having similar semantics
as T of char i.e. less<cv T*>(a, b) gives the same results as less<cv
void*>(a, b) which gives the same results as less<cv char*>((cv
char*)(cv void*)a, (cv char*)(cv void*)b).
</p></blockquote>
<p>
I'm also thinking there should be a footnote to 20.5.3/1 saying that if
A and B are similar types (4.4/4), comp<A>(a,b) returns the same value
as comp<B>(a,b) (where comp is less, less_equal, etc.). But this might
be problematic if there is some really funky operator overloading going
on that does different things based on cv (that should be undefined
behavior if somebody does that though). This at least should be
guaranteed for all POD types (especially pointers) that use the
built-in comparison operators.
</p>
<p><b>Rationale:</b></p>
<p>
less is already required to provide a strict weak ordering which is good enough
to detect overlapping memory situations.
</p>
<hr>
<h3><a name="504"></a>504. Integer types in pseudo-random number engine requirements</h3>
<p><b>Section:</b> 26.4.1 [rand.req], TR1 5.1.1 [tr.rand.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.req">issues</a> in [rand.req].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In [tr.rand.req], Paragraph 2 states that "... s is a value of integral type,
g is an ... object returning values of unsigned integral type ..."
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 5.1.1 [tr.rand.req], Paragraph 2 replace
</p>
<blockquote><p>
... s is a value of integral type, g is an lvalue of a type other than X that
defines a zero-argument function object returning values of <del>unsigned integral</del> type
<ins><tt>unsigned long int</tt></ins>,
...
</p></blockquote>
<p>
In 5.1.1 [tr.rand.seq], Table 16, replace in the line for X(s)
</p>
<blockquote><p>
creates an engine with the initial internal state
determined by <ins><tt>static_cast<unsigned long>(</tt></ins><tt><i>s</i></tt><ins><tt>)</tt></ins>
</p></blockquote>
<p><i>[
Mont Tremblant: Both s and g should be unsigned long.
This should refer to the constructor signatures. Jens provided wording post Mont Tremblant.
]</i></p>
<p><i>[
Berlin: N1932 adopts the proposed resolution: see 26.3.1.3/1e and Table 3 row 2. Moved
to Ready.
]</i></p>
<p><b>Rationale:</b></p>
<p>
Jens: Just requiring X(unsigned long) still makes it possible
for an evil library writer to also supply a X(int) that does something
unexpected. The wording above requires that X(s) always performs
as if X(unsigned long) would have been called. I believe that is
sufficient and implements our intentions from Mont Tremblant. I
see no additional use in actually requiring a X(unsigned long)
signature. u.seed(s) is covered by its reference to X(s), same
arguments.
</p>
<p><i>[
Portland: Subsumed by N2111.
]</i></p>
<hr>
<h3><a name="506"></a>506. Requirements of Distribution parameter for variate_generator</h3>
<p><b>Section:</b> 26.4 [rand], TR1 5.1.3 [tr.rand.var] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand">issues</a> in [rand].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 3 requires that template argument U (which corresponds to template
parameter Engine) satisfy all uniform random number generator requirements.
However, there is no analogous requirement regarding the template argument
that corresponds to template parameter Distribution. We believe there should
be, and that it should require that this template argument satisfy all random
distribution requirements.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Consequence 1: Remove the precondition clauses [tr.rand.var]/16 and /18.
</p>
<p>
Consequence 2: Add max() and min() functions to those distributions that
do not already have them.
</p>
<p><i>[
Mont Tremblant: Jens reccommends NAD, min/max not needed everywhere.
Marc supports having min and max to satisfy generic programming interface.
]</i></p>
<p><b>Rationale:</b></p>
<p>Berlin: N1932 makes this moot: variate_generator has been eliminated.</p>
<hr>
<h3><a name="509"></a>509. Uniform_int template parameters</h3>
<p><b>Section:</b> 26.4.8.1 [rand.dist.uni], TR1 5.1.7.1 [tr.rand.dist.iunif] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In [tr.rand.dist.iunif] the uniform_int distribution currently has a single
template parameter, IntType, used as the input_type and as the result_type
of the distribution. We believe there is no reason to conflate these types
in this way.
</p>
<p><b>Proposed resolution:</b></p>
<p>
We recommend that there be a second template parameter to
reflect the distribution's input_type, and that the existing first template
parameter continue to reflect (solely) the result_type:
</p>
<blockquote><pre>template< class IntType = int, UIntType = unsigned int >
class uniform_int
{
public:
// types
typedef UIntType input_type;
typedef IntType result_type;
</pre></blockquote>
<p><i>[
Berlin: Moved to NAD. N1932 makes this moot: the input_type template parameter has been
eliminated.
]</i></p>
<hr>
<h3><a name="510"></a>510. Input_type for bernoulli_distribution</h3>
<p><b>Section:</b> 26.4.8.2 [rand.dist.bern], TR1 5.1.7.2 [tr.rand.dist.bern] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In [tr.rand.dist.bern] the distribution currently requires;
</p>
<blockquote><pre>typedef int input_type;
</pre></blockquote>
<p><b>Proposed resolution:</b></p>
<p>
We believe this is an unfortunate choice, and recommend instead:
</p>
<blockquote><pre>typedef unsigned int input_type;
</pre></blockquote>
<p><i>[
Berlin: Moved to NAD. N1932 makes this moot: the input_type template parameter has been
eliminated.
]</i></p>
<hr>
<h3><a name="511"></a>511. Input_type for binomial_distribution</h3>
<p><b>Section:</b> 26.4.8 [rand.dist], TR1 5.1.7.5 [tr.rand.dist.bin] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.dist">issues</a> in [rand.dist].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Unlike all other distributions in TR1, this binomial_distribution has an
implementation-defined input_type. We believe this is an unfortunate choice,
because it hinders users from writing portable code. It also hinders the
writing of compliance tests. We recommend instead:
</p>
<blockquote><pre>typedef RealType input_type;
</pre></blockquote>
<p>
While this choice is somewhat arbitrary (as it was for some of the other
distributions), we make this particular choice because (unlike all other
distributions) otherwise this template would not publish its RealType
argument and so users could not write generic code that accessed this
second template parameter. In this respect, the choice is consistent with
the other distributions in TR1.
</p>
<p>
We have two reasons for recommending that a real type be specified instead.
One reason is based specifically on characteristics of binomial distribution
implementations, while the other is based on mathematical characteristics of
probability distribution functions in general.
</p>
<p>
Implementations of binomial distributions commonly use Stirling approximations
for values in certain ranges. It is far more natural to use real values to
represent these approximations than it would be to use integral values to do
so. In other ranges, implementations reply on the Bernoulli distribution to
obtain values. While TR1's bernoulli_distribution::input_type is specified as
int, we believe this would be better specified as double.
</p>
<p>
This brings us to our main point: The notion of a random distribution rests
on the notion of a cumulative distribution function, which in turn mathematically
depends on a continuous dependent variable. Indeed, such a distribution function
would be meaningless if it depended on discrete values such as integers - and this
remains true even if the distribution function were to take discrete steps.
</p>
<p>
Although this note is specifically about binomial_distribution::input_type,
we intend to recommend that all of the random distributions input_types be
specified as a real type (either a RealType template parameter, or double,
as appropriate).
</p>
<p>
Of the nine distributions in TR1, four already have this characteristic
(uniform_real, exponential_distribution, normal_distribution, and
gamma_distribution). We have already argued the case for the binomial the
remaining four distributions.
</p>
<p>
In the case of uniform_int, we believe that the calculations to produce an
integer result in a specified range from an integer in a different specified
range is best done using real arithmetic. This is because it involves a
product, one of whose terms is the ratio of the extents of the two ranges.
Without real arithmetic, the results become less uniform: some numbers become
more (or less) probable that they should be. This is, of course, undesireable
behavior in a uniform distribution.
</p>
<p>
Finally, we believe that in the case of the bernoulli_distribution (briefly
mentioned earlier), as well as the cases of the geometric_distribution and the
poisson_distribution, it would be far more natural to have a real input_type.
This is because the most natural computation involves the random number
delivered and the distribution's parameter p (in the case of bernoulli_distribution,
for example, the computation is a comparison against p), and p is already specified
in each case as having some real type.
</p>
<p><b>Proposed resolution:</b></p>
<blockquote><pre>typedef RealType input_type;
</pre></blockquote>
<p><i>[
Berlin: Moved to NAD. N1932 makes this moot: the input_type template parameter has been
eliminated.
]</i></p>
<hr>
<h3><a name="512"></a>512. Seeding subtract_with_carry_01 from a single unsigned long</h3>
<p><b>Section:</b> 26.4.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.eng">issues</a> in [rand.eng].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 8 specifies the algorithm by which a subtract_with_carry_01 engine
is to be seeded given a single unsigned long. This algorithm is seriously
flawed in the case where the engine parameter w (also known as word_size)
exceeds 31 [bits]. The key part of the paragraph reads:
</p>
<blockquote><p>
sets x(-r) ... x(-1) to (lcg(1)*2**(-w)) mod 1
</p></blockquote>
<p>
and so forth.
</p>
<p>
Since the specified linear congruential engine, lcg, delivers numbers with
a maximum of 2147483563 (just a shade under 31 bits), then when w is, for
example, 48, each of the x(i) will be less than 2**-17. The consequence
is that roughly the first 400 numbers delivered will be conspicuously
close to either zero or one.
</p>
<p>
Unfortunately, this is not an innocuous flaw: One of the predefined engines
in [tr.rand.predef], namely ranlux64_base_01, has w = 48 and would exhibit
this poor behavior, while the original N1378 proposal states that these
pre-defined engines are intended to be of "known good properties."
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 5.1.4.4 [tr.rand.eng.sub1], replace the "effects" clause for
void seed(unsigned long value = 19780503) by
</p>
<blockquote><p>
<i>Effects:</i> If <tt>value == 0</tt>, sets value to <tt>19780503</tt>. In any
case, <del>with a linear congruential generator <tt>lcg</tt>(i) having parameters
<tt><i>m<sub>lcg</sub></i> = 2147483563</tt>, <tt><i>a<sub>lcg</sub></i> = 40014</tt>,
<tt><i>c<sub>lcg</sub></i> = 0</tt>, and <tt><i>lcg</i>(0) = value</tt>,</del>
sets <ins>carry<tt>(-1)</tt> and</ins> <tt>x(-r) … x(-1)</tt>
<ins>as if executing</ins></p>
<blockquote><pre><ins>
linear_congruential<unsigned long, 40014, 0, 2147483563> lcg(value);
seed(lcg);
</ins></pre></blockquote>
<p>
<del>to <tt>(<i>lcg</i>(1) ˇ 2<sup>-<i>w</i></sup>) mod 1
… (<i>lcg</i>(<i>r</i>) ˇ 2<sup>-<i>w</i></sup>) mod 1</tt>,
respectively. If <tt><i>x</i>(-1) == 0</tt>, sets carry<tt>(-1) = 2<sup>-<i>w</i></sup></tt>,
else sets carry<tt>(-1) = 0</tt>.</del></p>
</blockquote>
<p><i>[
Jens provided revised wording post Mont Tremblant.
]</i></p>
<p><i>[
Berlin: N1932 adopts the originally-proposed resolution of the issue.
Jens's supplied wording is a clearer description of what is
intended. Moved to Ready.
]</i></p>
<p><b>Rationale:</b></p>
<p>
Jens: I'm using an explicit type here, because fixing the
prose would probably not qualify for the (with issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a> even
stricter) requirements we have for seed(Gen&).
</p>
<p><i>[
Portland: Subsumed by N2111.
]</i></p>
<hr>
<h3><a name="513"></a>513. Size of state for subtract_with_carry_01</h3>
<p><b>Section:</b> 26.4.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.eng">issues</a> in [rand.eng].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 3 begins:
</p>
<blockquote><p>
The size of the state is r.
</p></blockquote>
<p>
However, this is not quite consistent with the remainder of the paragraph
which specifies a total of nr+1 items in the textual representation of
the state. We recommend the sentence be corrected to match:
</p>
<blockquote><p>
The size of the state is nr+1.
</p></blockquote>
<p>
To give meaning to the coefficient n, it may be also desirable to move
n's definition from later in the paragraph. Either of the following
seem reasonable formulations:
</p>
<blockquote><p>
With n=..., the size of the state is nr+1.
</p></blockquote>
<blockquote><p>
The size of the state is nr+1, where n=... .
</p></blockquote>
<p><b>Proposed resolution:</b></p>
<p><i>[
Jens: I plead for "NAD" on the grounds that "size of state" is only
used as an argument for big-O complexity notation, thus
constant factors and additions don't count.
]</i></p>
<p><i>[
Berlin: N1932 adopts the proposed NAD.
]</i></p>
<hr>
<h3><a name="514"></a>514. Size of state for subtract_with_carry</h3>
<p><b>Section:</b> 26.4.3.3 [rand.eng.sub], TR1 5.1.4.3 [tr.rand.eng.sub] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 2 begins:
</p>
<blockquote><p>
The size of the state is r.
</p></blockquote>
<p>
However, the next sentence specifies a total of r+1 items in the textual
representation of the state, r specific x's as well as a specific carry.
This makes a total of r+1 items that constitute the size of the state,
rather than r.
</p>
<p><b>Proposed resolution:</b></p>
<p>
We recommend the sentence be corrected to match:
</p>
<blockquote><p>
The size of the state is r+1.
</p></blockquote>
<p><i>[
Jens: I plead for "NAD" on the grounds that "size of state" is only
used as an argument for big-O complexity notation, thus
constant factors and additions don't count.
]</i></p>
<p><i>[
Berlin: N1932 adopts the proposed NAD.
]</i></p>
<hr>
<h3><a name="515"></a>515. Random number engine traits</h3>
<p><b>Section:</b> 26.4.2 [rand.synopsis], TR1 5.1.2 [tr.rand.synopsis] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.synopsis">issues</a> in [rand.synopsis].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
To accompany the concept of a pseudo-random number engine as defined in Table 17,
we propose and recommend an adjunct template, engine_traits, to be declared in
[tr.rand.synopsis] as:
</p>
<blockquote><pre>template< class PSRE >
class engine_traits;
</pre></blockquote>
<p>
This template's primary purpose would be as an aid to generic programming involving
pseudo-random number engines. Given only the facilities described in tr1, it would
be very difficult to produce any algorithms involving the notion of a generic engine.
The intent of this proposal is to provide, via engine_traits<>, sufficient
descriptive information to allow an algorithm to employ a pseudo-random number engine
without regard to its exact type, i.e., as a template parameter.
</p>
<p>
For example, today it is not possible to write an efficient generic function that
requires any specific number of random bits. More specifically, consider a
cryptographic application that internally needs 256 bits of randomness per call:
</p>
<blockquote><pre>template< class Eng, class InIter, class OutIter >
void crypto( Eng& e, InIter in, OutIter out );
</pre></blockquote>
<p>
Without knowning the number of bits of randomness produced per call to a provided
engine, the algorithm has no means of determining how many times to call the engine.
</p>
<p>
In a new section [tr.rand.eng.traits], we proposed to define the engine_traits
template as:
</p>
<blockquote><pre>template< class PSRE >
class engine_traits
{
static std::size_t bits_of_randomness = 0u;
static std::string name() { return "unknown_engine"; }
// TODO: other traits here
};
</pre></blockquote>
<p>
Further, each engine described in [tr.rand.engine] would be accompanied by a
complete specialization of this new engine_traits template.
</p>
<p><b>Proposed resolution:</b></p>
<p><i>[
Berlin: Walter: While useful for implementation per TR1, N1932 has no need for this
feature. Recommend close as NAD.
]</i></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1932.pdf">N1932</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2111.pdf">N2111</a>
covers this. Already in WP.
</p>
<hr>
<h3><a name="516"></a>516. Seeding subtract_with_carry_01 using a generator</h3>
<p><b>Section:</b> 26.4.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.eng">issues</a> in [rand.eng].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 6 says:
</p>
<blockquote><p>
... obtained by successive invocations of g, ...
</p></blockquote>
<p>
We recommend instead:
</p>
<blockquote><p>
... obtained by taking successive invocations of g mod 2**32, ...
</p></blockquote>
<p>
as the context seems to require only 32-bit quantities be used here.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Berlin: N1932 adopts the proposed resultion: see 26.3.3.4/7. Moved to Ready.
</p>
<p><i>[
Portland: Subsumed by N2111.
]</i></p>
<hr>
<h3><a name="517"></a>517. Should include name in external representation</h3>
<p><b>Section:</b> 26.4.1 [rand.req], TR1 5.1.1 [tr.rand.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Walter Brown <b>Date:</b> 2005-07-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.req">issues</a> in [rand.req].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The last two rows of Table 16 deal with the i/o requirements of an engine,
specifying that the textual representation of an engine's state,
appropriately formatted, constitute the engine's external representation.
</p>
<p>
This seems adequate when an engine's type is known. However, it seems
inadequate in the context of generic code, where it becomes useful and
perhaps even necessary to determine an engine's type via input.
</p>
<p>
</p>
<p><b>Proposed resolution:</b></p>
<p>
We therefore recommend that, in each of these two rows of Table 16, the
text "textual representation" be expanded so as to read "engine name
followed by the textual representation."
</p>
<p><i>[
Berlin: N1932 considers this NAD. This is a QOI issue.
]</i></p>
<hr>
<h3><a name="525"></a>525. type traits definitions not clear</h3>
<p><b>Section:</b> 20.4.4 [meta.unary], TR1 4.5 [tr.meta.unary] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Robert Klarer <b>Date:</b> 2005-07-11</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
It is not completely clear how the primary type traits deal with
cv-qualified types. And several of the secondary type traits
seem to be lacking a definition.
</p>
<p><i>[
Berlin: Howard to provide wording.
]</i></p>
<p><b>Proposed resolution:</b></p>
<p>
Wording provided in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2028.html">N2028</a>.
A
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2157.html">revision (N2157)</a>
provides more detail for motivation.
</p>
<p><b>Rationale:</b></p>
Solved by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2157.html">revision (N2157)</a>
in the WP.
<hr>
<h3><a name="526"></a>526. Is it undefined if a function in the standard changes in parameters?</h3>
<p><b>Section:</b> 23.1.1 [sequence.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Chris Jefferson <b>Date:</b> 2005-09-14</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#sequence.reqmts">issues</a> in [sequence.reqmts].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Problem: There are a number of places in the C++ standard library where
it is possible to write what appear to be sensible ways of calling
functions, but which can cause problems in some (or all)
implementations, as they cause the values given to the function to be
changed in a way not specified in standard (and therefore not coded to
correctly work). These fall into two similar categories.
</p>
<p>
1) Parameters taken by const reference can be changed during execution
of the function
</p>
<p>
Examples:
</p>
<p>
Given std::vector<int> v:
</p>
<p>
v.insert(v.begin(), v[2]);
</p>
<p>
v[2] can be changed by moving elements of vector
</p>
<p>
Given std::list<int> l:
</p>
<p>
l.remove(*l.begin());
</p>
<p>
Will delete the first element, and then continue trying to access it.
This is particularily vicious, as it will appear to work in almost all
cases.
</p>
<p>
2) A range is given which changes during the execution of the function:
Similarly,
</p>
<p>
v.insert(v.begin(), v.begin()+4, v.begin()+6);
</p>
<p>
This kind of problem has been partly covered in some cases. For example
std::copy(first, last, result) states that result cannot be in the range
[first, last). However, does this cover the case where result is a
reverse_iterator built from some iterator in the range [first, last)?
Also, std::copy would still break if result was reverse_iterator(last +
1), yet this is not forbidden by the standard
</p>
<p>
Solution:
</p>
<p>
One option would be to try to more carefully limit the requirements of
each function. There are many functions which would have to be checked.
However as has been shown in the std::copy case, this may be difficult.
A simpler, more global option would be to somewhere insert text similar to:
</p>
<p>
If the execution of any function would change either any values passed
by reference or any value in any range passed to a function in a way not
defined in the definition of that function, the result is undefined.
</p>
<p>
Such code would have to at least cover chapters 23 and 25 (the sections
I read through carefully). I can see no harm on applying it to much of
the rest of the standard.
</p>
<p>
Some existing parts of the standard could be improved to fit with this,
for example the requires for 25.2.1 (Copy) could be adjusted to:
</p>
<p>
Requires: For each non-negative integer n < (last - first), assigning to
*(result + n) must not alter any value in the range [first + n, last).
</p>
<p>
However, this may add excessive complication.
</p>
<p>
One other benefit of clearly introducing this text is that it would
allow a number of small optimisations, such as caching values passed
by const reference.
</p>
<p>
Matt Austern adds that this issue also exists for the <tt>insert</tt> and
<tt>erase</tt> members of the ordered and unordered associative containers.
</p>
<p><i>[
Berlin: Lots of controversey over how this should be solved. Lots of confusion
as to whether we're talking about self referencing iterators or references.
Needs a good survey as to the cases where this matters, for which
implementations, and how expensive it is to fix each case.
]</i></p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD.
</p>
<ul>
<li><tt>vector::insert(iter, value)</tt> is required to work because the standard
doesn't give permission for it not to work.</li>
<li><tt>list::remove(value)</tt> is required to work because the standard
doesn't give permission for it not to work.</li>
<li><tt>vector::insert(iter, iter, iter)</tt> is not required to work because
23.1.1 [sequence.reqmts], p4 says so.</li>
<li><tt>copy</tt> has to work, except where 25.2.1 [alg.copy] says
it doesn't have to work. While a language lawyer can tear this wording apart,
it is felt that the wording is not prone to accidental interpretation.</li>
<li>The current working draft provide exceptions for the unordered associative
containers similar to the containers requirements which exempt the member
template insert functions from self referencing.</li>
</ul>
<hr>
<h3><a name="528"></a>528. <tt>const_iterator</tt> <tt>iterator</tt> issue when they are the same type</h3>
<p><b>Section:</b> 23.4 [unord], TR1 6.3.4 [tr.unord.unord] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Paolo Carlini <b>Date:</b> 2005-10-12</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord">active issues</a> in [unord].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord">issues</a> in [unord].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
while implementing the resolution of issue 6.19 I'm noticing the
following: according to 6.3.4.3/2 (and 6.3.4.5/2), for unordered_set and
unordered_multiset:
</p>
<blockquote><p>
"The iterator and const_iterator types are both const types. It is
unspecified whether they are the same type"
</p></blockquote>
<p>
Now, according to the resolution of 6.19, we have overloads of insert
with hint and erase (single and range) both for iterator and
const_iterator, which, AFAICS, can be meaningful at the same time *only*
if iterator and const_iterator *are* in fact different types.
</p>
<p>
Then, iterator and const_iterator are *required* to be different types?
Or that is an unintended consequence? Maybe the overloads for plain
iterators should be added only to unordered_map and unordered_multimap?
Or, of course, I'm missing something?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add to 6.3.4.3p2 (and 6.3.4.5p2):
</p>
<p>
2 ... The iterator and const_iterator types are both <del>const</del>
<ins>constant</ins> iterator types.
It is unspecified whether they are the same type.
</p>
<p>
Add a new subsection to 17.4.4 [lib.conforming]:
</p>
<blockquote>
<p>
An implementation shall not supply an overloaded function
signature specified in any library clause if such a signature
would be inherently ambiguous during overload resolution
due to two library types referring to the same type.
</p>
<p>
[Note: For example, this occurs when a container's iterator
and const_iterator types are the same. -- end note]
</p>
</blockquote>
<p><i>[
Post-Berlin: Beman supplied wording.
]</i></p>
<p><b>Rationale:</b></p>
Toronto: The first issue has been fixed by N2350 (the insert and erase members
are collapsed into one signature). Alisdair to open a separate issue on the
chapter 17 wording.
<hr>
<h3><a name="532"></a>532. Tuple comparison</h3>
<p><b>Section:</b> 20.3.1.5 [tuple.rel], TR1 6.1.3.5 [tr.tuple.rel] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Pending NAD Editorial</a>
<b>Submitter:</b> David Abrahams <b>Date:</b> 2005-11-29</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Pending%20NAD%20Editorial">Pending NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Where possible, tuple comparison operators <,<=,=>, and > ought to be
defined in terms of std::less rather than operator<, in order to
support comparison of tuples of pointers.
</p>
<p><b>Proposed resolution:</b></p>
<p>
change 6.1.3.5/5 from:
</p>
<blockquote><p>
Returns: The result of a lexicographical comparison between t and
u. The result is defined as: (bool)(get<0>(t) < get<0>(u)) ||
(!(bool)(get<0>(u) < get<0>(t)) && ttail < utail), where rtail for
some tuple r is a tuple containing all but the first element of
r. For any two zero-length tuples e and f, e < f returns false.
</p></blockquote>
<p>
to:
</p>
<blockquote>
<p>
Returns: The result of a lexicographical comparison between t and
u. For any two zero-length tuples e and f, e < f returns false.
Otherwise, the result is defined as: cmp( get<0>(t), get<0>(u)) ||
(!cmp(get<0>(u), get<0>(t)) && ttail < utail), where rtail for some
tuple r is a tuple containing all but the first element of r, and
cmp(x,y) is an unspecified function template defined as follows.
</p>
<p>
Where T is the type of x and U is the type of y:
</p>
<p>
if T and U are pointer types and T is convertible to U, returns
less<U>()(x,y)
</p>
<p>
otherwise, if T and U are pointer types, returns less<T>()(x,y)
</p>
<p>
otherwise, returns (bool)(x < y)
</p>
</blockquote>
<p><i>[
Berlin: This issue is much bigger than just tuple (pair, containers,
algorithms). Dietmar will survey and work up proposed wording.
]</i></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD. This will be fixed with the next revision of concepts.
</p>
<hr>
<h3><a name="536"></a>536. Container iterator constructor and explicit convertibility</h3>
<p><b>Section:</b> 23.1 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Joaquín M López Muńoz <b>Date:</b> 2005-12-17</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements">active issues</a> in [container.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements">issues</a> in [container.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#589">589</a></p>
<p><b>Discussion:</b></p>
<p>
The iterator constructor X(i,j) for containers as defined in 23.1.1 and
23.2.2 does only require that i and j be input iterators but
nothing is said about their associated value_type. There are three
sensible
options:
</p>
<ol>
<li>iterator's value_type is exactly X::value_type (modulo cv).</li>
<li>iterator's value_type is *implicitly* convertible to X::value_type.</li>
<li>iterator's value_type is *explicitly* convertible to X::value_type.</li>
</ol>
<p>
The issue has practical implications, and stdlib vendors have
taken divergent approaches to it: Dinkumware follows 2,
libstdc++ follows 3.
</p>
<p>
The same problem applies to the definition of insert(p,i,j) for
sequences and insert(i,j) for associative contianers, as well as
assign.
</p>
<p><i>[
The following added by Howard and the example code was originally written by
Dietmar.
]</i></p>
<p>
Valid code below?
</p>
<blockquote><pre>#include <vector>
#include <iterator>
#include <iostream>
struct foo
{
explicit foo(int) {}
};
int main()
{
std::vector<int> v_int;
std::vector<foo> v_foo1(v_int.begin(), v_int.end());
std::vector<foo> v_foo2((std::istream_iterator<int>(std::cin)),
std::istream_iterator<int>());
}
</pre></blockquote>
<p><i>[
Berlin: Some support, not universal, for respecting the explicit qualifier.
]</i></p>
<p><b>Proposed resolution:</b></p>
<hr>
<h3><a name="544"></a>544. minor NULL problems in C.2</h3>
<p><b>Section:</b> C.2 [diff.library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2005-11-25</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
According to C.2.2.3, p1, "the macro NULL, defined in any of <clocale>,
<cstddef>, <cstdio>, <cstdlib>, <cstring>, <ctime>,
or <cwchar>." This is consistent with the C standard.
</p>
<p>
However, Table 95 in C.2 fails to mention <clocale> and <cstdlib>.
</p>
<p>
In addition, C.2, p2 claims that "The C++ Standard library provides
54 standard macros from the C library, as shown in Table 95." While
table 95 does have 54 entries, since a couple of them (including the
NULL macro) are listed more than once, the actual number of macros
defined by the C++ Standard Library may not be 54.
</p>
<p><b>Proposed resolution:</b></p>
<p>
I propose we add <clocale> and <cstdlib> to Table 96 and remove the
number of macros from C.2, p2 and reword the sentence as follows:
</p>
<blockquote><p>
The C++ Standard library <del>provides 54 standard macros from</del>
<ins>defines a number macros corresponding to those defined by</ins> the C
<ins>Standard</ins> library, as shown in Table 96.
</p></blockquote>
<p><i>[
Portland: Resolution is considered editorial. It will be incorporated into the WD.
]</i></p>
<hr>
<h3><a name="547"></a>547. division should be floating-point, not integer</h3>
<p><b>Section:</b> 26.4 [rand], TR1 5.1 [tr.rand] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2006-01-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand">issues</a> in [rand].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 10 describes how a variate generator uses numbers produced by an
engine to pass to a generator. The sentence that concerns me is: "Otherwise, if
the value for engine_value_type::result_type is true and the value for
Distribution::input_type is false [i.e. if the engine produces integers and the
engine wants floating-point values], then the numbers in s_eng are divided by
engine().max() - engine().min() + 1 to obtain the numbers in s_e." Since the
engine is producing integers, both the numerator and the denominator are
integers and we'll be doing integer division, which I don't think is what we
want. Shouldn't we be performing a conversion to a floating-point type first?
</p>
<p><b>Proposed resolution:</b></p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD as the affected section is now gone and so the issue is moot.
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2111.pdf">N2111</a>.
</p>
<hr>
<h3><a name="548"></a>548. May random_device block?</h3>
<p><b>Section:</b> 26.4.6 [rand.device], TR1 5.1.6 [tr.rand.device] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2006-01-10</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Class random_device "produces non-deterministic random numbers", using some
external source of entropy. In most real-world systems, the amount of available
entropy is limited. Suppose that entropy has been exhausted. What is an
implementation permitted to do? In particular, is it permitted to block
indefinitely until more random bits are available, or is the implementation
required to detect failure immediately? This is not an academic question. On
Linux a straightforward implementation would read from /dev/random, and "When
the entropy pool is empty, reads to /dev/random will block until additional
environmental noise is gathered." Programmers need to know whether random_device
is permitted to (or possibly even required to?) behave the same way.
</p>
<p><i>[
Berlin: Walter: N1932 considers this NAD. Does the standard specify whether std::cin
may block?
]</i></p>
<p>
See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2391.pdf">N2391</a> and
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2423.pdf">N2423</a>
for some further discussion.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Adopt the proposed resolution in
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2423.pdf">N2423</a> (NAD).
</p>
<hr>
<h3><a name="549"></a>549. Undefined variable in binomial_distribution</h3>
<p><b>Section:</b> 26.4.8 [rand.dist], TR1 5.1.7.5 [tr.rand.dist.bin] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Matt Austern <b>Date:</b> 2006-01-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.dist">issues</a> in [rand.dist].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Paragraph 1 says that "A binomial distributon random distribution produces
integer values i>0 with p(i) = (n choose i) * p*i * (1-p)^(t-i), where t and
p are the parameters of the distribution. OK, that tells us what t, p, and i
are. What's n?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Berlin: Typo: "n" replaced by "t" in N1932: see 26.3.7.2.2/1.
</p>
<p><i>[
Portland: Subsumed by N2111.
]</i></p>
<hr>
<h3><a name="553"></a>553. very minor editorial change intptr_t / uintptr_t</h3>
<p><b>Section:</b> 18.3.1 [cstdint.syn], TR1 8.22.1 [tr.c99.cstdint.syn] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Paolo Carlini <b>Date:</b> 2006-01-30</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In the synopsis, some types are identified as optional: int8_t, int16_t,
and so on, consistently with C99, indeed.
</p>
<p>
On the other hand, intptr_t and uintptr_t, are not marked as such and
probably should, consistently with C99, 7.18.1.4.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 18.3.1 [cstdint.syn]:
</p>
<blockquote><pre>...
typedef <i>signed integer type</i> intptr_t; <ins><i>// optional</i></ins>
...
typedef <i>unsigned integer type</i> uintptr_t; <ins><i>// optional</i></ins>
...
</pre></blockquote>
<p><b>Rationale:</b></p>
Recommend NAD and fix as editorial with the proposed resolution.
<hr>
<h3><a name="554"></a>554. Problem with lwg DR 184 numeric_limits<bool></h3>
<p><b>Section:</b> 18.2.1.5 [numeric.special] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Howard Hinnant <b>Date:</b> 2006-01-29</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#numeric.special">issues</a> in [numeric.special].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
I believe we have a bug in the resolution of:
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#184">lwg 184</a>
(WP status).
</p>
<p>
The resolution spells out each member of <tt>numeric_limits<bool></tt>.
The part I'm having a little trouble with is:
</p>
<blockquote><pre>static const bool traps = false;
</pre></blockquote>
<p>
Should this not be implementation defined? Given:
</p>
<blockquote><pre>int main()
{
bool b1 = true;
bool b2 = false;
bool b3 = b1/b2;
}
</pre></blockquote>
<p>
If this causes a trap, shouldn't <tt>numeric_limits<bool>::traps</tt> be
<tt>true</tt>?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 18.2.1.5p3:
</p>
<blockquote><p>
-3- The specialization for <tt>bool</tt> shall be provided as follows: </p>
<blockquote><pre>namespace std {
template <> class numeric_limits<bool> {
...
static const bool traps = <del>false</del> <ins><i>implementation-defined</i></ins>;
...
};
}
</pre></blockquote>
</blockquote>
<p><i>[
Redmond: NAD because traps refers to values, not operations. There is no bool
value that will trap.
]</i></p>
<hr>
<h3><a name="555"></a>555. TR1, 8.21/1: typo</h3>
<p><b>Section:</b> TR1 8.21 [tr.c99.boolh] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Paolo Carlini <b>Date:</b> 2006-02-02</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
This one, if nobody noticed it yet, seems really editorial:
s/cstbool/cstdbool/
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 8.21p1:
</p>
<blockquote><p>
-1- The header behaves as if it defines the additional macro defined in
<tt><cst<ins>d</ins>bool></tt> by including the header <tt><cstdbool></tt>.
</p></blockquote>
<p><i>[
Redmond: Editorial.
]</i></p>
<hr>
<h3><a name="558"></a>558. lib.input.iterators Defect</h3>
<p><b>Section:</b> 24.1.1 [input.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> David Abrahams <b>Date:</b> 2006-02-09</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#input.iterators">issues</a> in [input.iterators].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<blockquote>
<p>
24.1.1 Input iterators [lib.input.iterators]
</p>
<p>
1 A class or a built-in type X satisfies the requirements of an
input iterator for the value type T if the following expressions are
valid, where U is the type of any specified member of type T, as
shown in Table 73.
</p>
</blockquote>
<p>
There is no capital U used in table 73. There is a lowercase u, but
that is clearly not meant to denote a member of type T. Also, there's
no description in 24.1.1 of what lowercase a means. IMO the above
should have been...Hah, a and b are already covered in 24.1/11, so maybe it
should have just been:
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 24.1.1p1:
</p>
<blockquote><p>
-1- A class or a built-in type <tt>X</tt> satisfies the requirements of an
input iterator for the value type <tt>T</tt> if the following expressions
are valid<del>, where <tt>U</tt> is the type of any specified member of type
<tt>T</tt>,</del> as shown in Table 73.
</p></blockquote>
<p><i>[
Portland: Editorial.
]</i></p>
<hr>
<h3><a name="560"></a>560. User-defined allocators without default constructor</h3>
<p><b>Section:</b> 20.1.2 [allocator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Sergey P. Derevyago <b>Date:</b> 2006-02-17</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#allocator.requirements">active issues</a> in [allocator.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#allocator.requirements">issues</a> in [allocator.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<h4>1. The essence of the problem.</h4>
<p>
User-defined allocators without default constructor are not explicitly
supported by the standard but they can be supported just like std::vector
supports elements without default constructor.
</p>
<p>
As a result, there exist implementations that work well with such allocators
and implementations that don't.
</p>
<h4>2. The cause of the problem.</h4>
<p>
1) The standard doesn't explicitly state this intent but it should. In
particular, 20.1.5p5 explicitly state the intent w.r.t. the allocator
instances that compare non-equal. So it can similarly state the intent w.r.t.
the user-defined allocators without default constructor.
</p>
<p>
2) Some container operations are obviously underspecified. In particular,
21.3.7.1p2 tells:
</p>
<blockquote><pre>template<class charT, class traits, class Allocator>
basic_string<charT,traits,Allocator> operator+(
const charT* lhs,
const basic_string<charT,traits,Allocator>& rhs
);
</pre>
<p>
Returns: <tt>basic_string<charT,traits,Allocator>(lhs) + rhs</tt>.
</p>
</blockquote>
<p>
That leads to the basic_string<charT,traits,Allocator>(lhs, Allocator()) call.
Obviously, the right requirement is:
</p>
<blockquote><p>
Returns: <tt>basic_string<charT,traits,Allocator>(lhs, rhs.get_allocator()) + rhs</tt>.
</p></blockquote>
<p>
It seems like a lot of DRs can be submitted on this "Absent call to
get_allocator()" topic.
</p>
<h4>3. Proposed actions.</h4>
<p>
1) Explicitly state the intent to allow for user-defined allocators without
default constructor in 20.1.5 Allocator requirements.
</p>
<p>
2) Correct all the places, where a correct allocator object is available
through the get_allocator() call but default Allocator() gets passed instead.
</p>
<h4>4. Code sample.</h4>
<p>
Let's suppose that the following memory pool is available:
</p>
<blockquote><pre>class mem_pool {
// ...
void* allocate(size_t size);
void deallocate(void* ptr, size_t size);
};
</pre></blockquote>
<p>
So the following allocator can be implemented via this pool:
</p>
<blockquote><pre>class stl_allocator {
mem_pool& pool;
public:
explicit stl_allocator(mem_pool& mp) : pool(mp) {}
stl_allocator(const stl_allocator& sa) : pool(sa.pool) {}
template <class U>
stl_allocator(const stl_allocator<U>& sa) : pool(sa.get_pool()) {}
~stl_allocator() {}
pointer allocate(size_type n, std::allocator<void>::const_pointer = 0)
{
return (n!=0) ? static_cast<pointer>(pool.allocate(n*sizeof(T))) : 0;
}
void deallocate(pointer p, size_type n)
{
if (n!=0) pool.deallocate(p, n*sizeof(T));
}
// ...
};
</pre></blockquote>
<p>
Then the following code works well on some implementations and doesn't work on
another:
</p>
<blockquote><pre>typedef basic_string<char, char_traits<char>, stl_allocator<char> >
tl_string;
mem_pool mp;
tl_string s1("abc", stl_allocator<int>(mp));
printf("(%s)\n", ("def"+s1).c_str());
</pre></blockquote>
<p>
In particular, on some implementations the code can't be compiled without
default stl_allocator() constructor.
</p>
<p>
The obvious way to solve the compile-time problems is to intentionally define
a NULL pointer dereferencing default constructor
</p>
<blockquote><pre>stl_allocator() : pool(*static_cast<mem_pool*>(0)) {}
</pre></blockquote>
<p>
in a hope that it will not be called. The problem is that it really gets
called by operator+(const char*, const string&) under the current 21.3.7.1p2
wording.
</p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD. <tt>operator+()</tt> with <tt>string</tt> already requires the desired
semantics of copying the allocator from one of the strings (<i>lhs</i> when there is a choice).
</p>
<hr>
<h3><a name="569"></a>569. Postcondition for basic_ios::clear(iostate) incorrectly stated</h3>
<p><b>Section:</b> 27.4.4.3 [iostate.flags] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>
<b>Submitter:</b> Seungbeom Kim <b>Date:</b> 2006-03-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iostate.flags">issues</a> in [iostate.flags].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Dup">Dup</a> status.</p>
<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#272">272</a></p>
<p><b>Discussion:</b></p>
<p>
Section: 27.4.4.3 [lib.iostate.flags]
</p>
<p>
Paragraph 4 says:
</p>
<blockquote>
<blockquote><pre>void clear(iostate <i>state</i> = goodbit);
</pre></blockquote>
<p>
<i>Postcondition:</i> If <tt>rdbuf()!=0</tt> then <tt><i>state</i> == rdstate();</tt>
otherwise <tt>rdstate()==<i>state</i>|ios_base::badbit</tt>.
</p>
</blockquote>
<p>
The postcondition "rdstate()==state|ios_base::badbit" is parsed as
"(rdstate()==state)|ios_base::badbit", which is probably what the
committee meant.
</p>
<p><b>Rationale:</b></p>
<hr>
<h3><a name="571"></a>571. Update C90 references to C99?</h3>
<p><b>Section:</b> 1.2 [intro.refs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Beman Dawes <b>Date:</b> 2006-04-08</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#intro.refs">issues</a> in [intro.refs].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
1.2 Normative references [intro.refs] of the WP currently refers to ISO/IEC
9899:1990, Programming languages - C. Should that be changed to ISO/IEC
9899:1999?
</p>
<p>
What impact does this have on the library?
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 1.2/1 [intro.refs] of the WP, change:
</p>
<blockquote>
<ul>
<li>ISO/IEC 9899:<del>1990</del><ins>1999 + TC1 + TC2</ins>, <i>Programming languages - C</i></li>
</ul>
</blockquote>
<p><b>Rationale:</b></p>
Recommend NAD, fixed editorially.
<hr>
<h3><a name="572"></a>572. Oops, we gave 507 WP status</h3>
<p><b>Section:</b> 26.4 [rand], TR1 5.1 [tr.rand] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Howard Hinnant <b>Date:</b> 2006-04-11</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand">issues</a> in [rand].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In Berlin, as a working group, we voted in favor of N1932 which makes issue 507 moot:
variate_generator has been eliminated. Then in full committee we voted to give
this issue WP status (mistakenly).
</p>
<p><b>Proposed resolution:</b></p>
<p>
Strike the proposed resolution of issue 507.
</p>
<p><i>[
post-Portland: Walter and Howard recommend NAD. The proposed resolution of 507 no longer
exists in the current WD.
]</i></p>
<p><b>Rationale:</b></p>
<p>
NAD. Will be moot once
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2135.pdf">N2135</a>
is adopted.
</p>
<hr>
<h3><a name="583"></a>583. div() for unsigned integral types</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Beman Dawes <b>Date:</b> 2006-06-15</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
There is no div() function for unsigned integer types.
</p>
<p>
There are several possible resolutions. The simplest one is noted below. Other
possibilities include a templated solution.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add to 26.7 [lib.c.math] paragraph 8:
</p>
<blockquote><pre>struct udiv_t div(unsigned, unsigned);
struct uldiv_t div(unsigned long, unsigned long);
struct ulldiv_t div(unsigned long long, unsigned long long);
</pre></blockquote>
<p><b>Rationale:</b></p>
Toronto: C99 does not have these unsigned versions because
the signed version exist just to define the implementation-defined behavior
of signed integer division. Unsigned integer division has no implementation-defined
behavior and thus does not need this treatment.
<hr>
<h3><a name="584"></a>584. missing int pow(int,int) functionality</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Beman Dawes <b>Date:</b> 2006-06-15</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
There is no pow() function for any integral type.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add something like:
</p>
<blockquote><pre>template< typename T>
T power( T x, int n );
// requires: n >=0
</pre></blockquote>
<p><b>Rationale:</b></p>
Toronto: We already have double pow(integral, integral) from 26.7 [c.math] p11.
<hr>
<h3><a name="587"></a>587. iststream ctor missing description</h3>
<p><b>Section:</b> D.7.2.1 [depr.istrstream.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Martin Sebor <b>Date:</b> 2006-06-22</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The <code>iststream(char*, streamsize)</code> ctor is in the class
synopsis in D.7.2 but its signature is missing in the description
below (in D.7.2.1).
</p>
<p><b>Proposed resolution:</b></p>
<p>
This seems like a simple editorial issue and the missing signature can
be added to the one for <code>const char*</code> in paragraph 2.
</p>
<p><i>[
post Oxford: Noted that it is already fixed in
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2284.pdf">N2284</a>
]</i></p>
<hr>
<h3><a name="590"></a>590. Type traits implementation latitude should be removed for C++0x</h3>
<p><b>Section:</b> 20.4 [meta], TR1 4.9 [tr.meta.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Beman Dawes <b>Date:</b> 2006-08-10</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta">issues</a> in [meta].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
20.4.9 [lib.meta.req], Implementation requirements, provides latitude for type
traits implementers that is not needed in C++0x. It includes the wording:
</p>
<blockquote><p>
[<i>Note:</i> the latitude granted to implementers in this clause is temporary,
and is expected to be removed in future revisions of this document. -- <i>end note</i>]
</p></blockquote>
<p>
Note:
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2157.html">N2157: Minor Modifications to the type traits Wording</a>
also has the intent of removing this wording from the WP.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Remove 20.4.9 [lib.meta.req] in its entirety from the WP.
</p>
<p><i>[
post-Oxford: Recommend NAD Editorial. This resolution is now in the
current working draft.
]</i></p>
<hr>
<h3><a name="591"></a>591. Misleading "built-in</h3>
<p><b>Section:</b> 18.2.1.2 [numeric.limits.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> whyglinux <b>Date:</b> 2006-08-08</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#numeric.limits.members">issues</a> in [numeric.limits.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
18.2.1.2 numeric_limits members [lib.numeric.limits.members]
Paragraph 7:
</p>
<blockquote><p>
"For built-in integer types, the number of non-sign bits in the
representation."
</p></blockquote>
<p>
26.1 Numeric type requirements [lib.numeric.requirements]
Footnote:
</p>
<blockquote><p>
"In other words, value types. These include built-in arithmetic types,
pointers, the library class complex, and instantiations of valarray for
value types."
</p></blockquote>
<p>
Integer types (which are bool, char, wchar_t, and the signed and
unsigned integer types) and arithmetic types (which are integer and
floating types) are all built-in types and thus there are no
non-built-in (that is, user-defined) integer or arithmetic types. Since
the redundant "built-in" in the above 2 sentences can mislead that
there may be built-in or user-defined integer and arithmetic types
(which is not correct), the "built-in" should be removed.
</p>
<p><b>Proposed resolution:</b></p>
<p>
18.2.1.2 numeric_limits members [lib.numeric.limits.members]
Paragraph 7:
</p>
<blockquote><p>
"For <del>built-in</del> integer types, the number of non-sign bits in the
representation."
</p></blockquote>
<p>
26.1 Numeric type requirements [lib.numeric.requirements]
Footnote:
</p>
<blockquote><p>
"In other words, value types. These include <del>built-in</del> arithmetic types,
pointers, the library class complex, and instantiations of valarray for
value types."
</p></blockquote>
<p><b>Rationale:</b></p>
<p>
Recommend NAD / Editorial. The proposed resolution is accepted as editorial.
</p>
<hr>
<h3><a name="592"></a>592. Incorrect treatment of rdbuf()->close() return type</h3>
<p><b>Section:</b> 27.8.1.9 [ifstream.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Pending NAD Editorial</a>
<b>Submitter:</b> Christopher Kohlhoff <b>Date:</b> 2006-08-17</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ifstream.members">issues</a> in [ifstream.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Pending%20NAD%20Editorial">Pending NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
I just spotted a minor problem in 27.8.1.7
[lib.ifstream.members] para 4 and also 27.8.1.13
[lib.fstream.members] para 4. In both places it says:
</p>
<blockquote>
<pre>void close();
</pre>
<p>
Effects: Calls rdbuf()->close() and, if that function returns false, ...
</p>
</blockquote>
<p>
However, basic_filebuf::close() (27.8.1.2) returns a pointer to the
filebuf on success, null on failure, so I think it is meant to
say "if that function returns a null pointer". Oddly, it is
correct for basic_ofstream.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 27.8.1.9 [ifstream.members], p5:
</p>
<blockquote><p>
<i>Effects:</i> Calls <tt>rdbuf()->close()</tt> and, if that function
<ins>fails (</ins>returns <del><tt>false</tt></del> <ins>a null pointer)</ins>,
calls <tt>setstate(failbit)</tt> (which may throw <tt>ios_base::failure</tt>
(27.4.4.3)).
</p></blockquote>
<p>
Change 27.8.1.17 [fstream.members], p5:
</p>
<blockquote><p>
<i>Effects:</i> Calls <tt>rdbuf()->close()</tt> and, if that function
<ins>fails (</ins>returns <del><tt>false</tt></del> <ins>a null pointer)</ins>,
calls <tt>setstate(failbit)</tt> (which may throw <tt>ios_base::failure</tt>
(27.4.4.3)).
</p></blockquote>
<p><i>[
Kona (2007): Proposed Disposition: NAD, Editorial
]</i></p>
<hr>
<h3><a name="594"></a>594. Disadvantages of defining Swappable in terms of CopyConstructible and Assignable</h3>
<p><b>Section:</b> 20.1.1 [utility.arg.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Pending NAD Editorial</a>
<b>Submitter:</b> Niels Dekker <b>Date:</b> 2006-11-02</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#utility.arg.requirements">active issues</a> in [utility.arg.requirements].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#utility.arg.requirements">issues</a> in [utility.arg.requirements].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Pending%20NAD%20Editorial">Pending NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
It seems undesirable to define the Swappable requirement in terms of
CopyConstructible and Assignable requirements. And likewise, once the
MoveConstructible and MoveAssignable requirements (N1860) have made it
into the Working Draft, it seems undesirable to define the Swappable
requirement in terms of those requirements. Instead, it appears
preferable to have the Swappable requirement defined exclusively in
terms of the existence of an appropriate swap function.
</p>
<p>
Section 20.1.4 [lib.swappable] of the current Working Draft (N2009)
says:
</p>
<blockquote><p>
The Swappable requirement is met by satisfying one or more of the
following conditions:</p>
<ul>
<li>
T is Swappable if T satisfies the CopyConstructible requirements
(20.1.3) and the Assignable requirements (23.1);
</li>
<li>
T is Swappable if a namespace scope function named swap exists in the
same namespace as the definition of T, such that the expression
swap(t,u) is valid and has the semantics described in Table 33.
</li>
</ul>
</blockquote>
I can think of three disadvantages of this definition:
<ol>
<li>
If a client's type T satisfies the first condition (T is both
CopyConstructible and Assignable), the client cannot stop T from
satisfying the Swappable requirement without stopping T from
satisfying the first condition.
<p>
A client might want to stop T from satisfying the Swappable
requirement, because swapping by means of copy construction and
assignment might throw an exception, and she might find a throwing
swap unacceptable for her type. On the other hand, she might not feel
the need to fully implement her own swap function for this type. In
this case she would want to be able to simply prevent algorithms that
would swap objects of type T from being used, e.g., by declaring a
swap function for T, and leaving this function purposely undefined.
This would trigger a link error, if an attempt would be made to use
such an algorithm for this type. For most standard library
implementations, this practice would indeed have the effect of
stopping T from satisfying the Swappable requirement.
</p>
</li>
<li>
A client's type T that does not satisfy the first condition can not be
made Swappable by providing a specialization of std::swap for T.
<p>
While I'm aware about the fact that people have mixed feelings about
providing a specialization of std::swap, it is well-defined to do so.
It sounds rather counter-intuitive to say that T is not Swappable, if
it has a valid and semantically correct specialization of std::swap.
Also in practice, providing such a specialization will have the same
effect as satisfying the Swappable requirement.
</p>
</li>
<li>
For a client's type T that satisfies both conditions of the Swappable
requirement, it is not specified which of the two conditions prevails.
After reading section 20.1.4 [lib.swappable], one might wonder whether
objects of T will be swapped by doing copy construction and
assignments, or by calling the swap function of T.
<p>
I'm aware that the intention of the Draft is to prefer calling the
swap function of T over doing copy construction and assignments. Still
in my opinion, it would be better to make this clear in the wording of
the definition of Swappable.
</p>
</li>
</ol>
<p>
I would like to have the Swappable requirement defined in such a way
that the following code fragment will correctly swap two objects of a
type T, if and only if T is Swappable:
</p>
<pre> using std::swap;
swap(t, u); // t and u are of type T.
</pre>
<p>
This is also the way Scott Meyers recommends calling a swap function,
in Effective C++, Third Edition, item 25.
</p>
<p>
Most aspects of this issue have been dealt with in a discussion on
comp.std.c++ about the Swappable requirement, from 13 September to 4
October 2006, including valuable input by David Abrahams, Pete Becker,
Greg Herlihy, Howard Hinnant and others.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change section 20.1.4 [lib.swappable] as follows:
</p>
<blockquote><p>
The Swappable requirement is met by satisfying
<del>one or more of the following conditions:</del>
<ins>the following condition:</ins></p>
<ul>
<li>
<del>T is Swappable if T satisfies the CopyConstructible requirements
(20.1.3) and the Assignable requirements (23.1);</del>
</li>
<li>
<del>
T is Swappable if a namespace scope function named swap exists in the
same namespace as the definition of T, such that the expression
swap(t,u) is valid and has the semantics described in Table 33.
</del>
T is Swappable if an unqualified function call swap(t,u) is valid
within the namespace std, and has the semantics described in Table 33.
</li>
</ul>
</blockquote>
<p><b>Rationale:</b></p>
<p>
Recommend NAD. Concepts, specifically
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2082.pdf">N2082</a>
and
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2084.pdf">N2084</a>,
will essentially rewrite this section and provide the desired semantics.
</p>
<hr>
<h3><a name="615"></a>615. Inconsistencies in Section 21.4</h3>
<p><b>Section:</b> 21.5 [c.strings] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Bo Persson <b>Date:</b> 2006-12-11</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.strings">issues</a> in [c.strings].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In the current draft N2134, 21.4/1 says
</p>
<p>
"Tables 59,228) 60, 61, 62,and 63 229) 230) describe headers <cctype>,
<cwctype>, <cstring>, <cwchar>, and <cstdlib> (character conversions),
respectively."
</p>
<p>
Here footnote 229 applies to table 62, not table 63.
</p>
<p>
Also, footnote 230 lists the new functions in table 63, "atoll, strtoll,
strtoull, strtof, and strtold added by TR1". However, strtof is not present
in table 63.
</p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<p><b>Rationale:</b></p>
<p>
Recommend NAD, editorial. Send to Pete.
</p>
<hr>
<h3><a name="633"></a>633. Return clause mentions undefined "type()"</h3>
<p><b>Section:</b> 20.5.15.2.5 [func.wrap.func.targ] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-02-03</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
20.5.15.2.5 [func.wrap.func.targ], p4 says:
</p>
<blockquote><p>
<i>Returns:</i> If <tt>type() == typeid(T)</tt>, a pointer to the stored
function target; otherwise a null pointer.
</p></blockquote>
<ol>
<li>
There exists neither a type, a typedef <tt>type</tt>, nor member
function <tt>type()</tt> in class template function nor in the global or
<tt>std</tt> namespace.
</li>
<li>
Assuming that <tt>type</tt> should have been <tt>target_type()</tt>,
this description would lead to false results, if <tt>T = <i>cv</i>
void</tt> due to returns clause 20.5.15.2.5 [func.wrap.func.targ], p1.
</li>
</ol>
<p><b>Proposed resolution:</b></p>
<p>
Change 20.5.15.2.5 [func.wrap.func.targ], p4:
</p>
<blockquote><p>
<i>Returns:</i> If <tt><del>type()</del> <ins>target_type()</ins> == typeid(T) <ins>&& typeid(T) !=
typeid(void)</ins></tt>, a pointer to the stored function target;
otherwise a null pointer.
</p></blockquote>
<p><i>[
Pete: Agreed. It's editorial, so I'll fix it.
]</i></p>
<hr>
<h3><a name="636"></a>636. 26.5.2.3 valarray::operator[]</h3>
<p><b>Section:</b> 26.5.2.3 [valarray.access] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Bo Persson <b>Date:</b> 2007-02-11</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#valarray.access">issues</a> in [valarray.access].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The signature of the const operator[] has been changed to return a const
reference.
</p>
<p>
The description in paragraph 1 still says that the operator returns by
value.
</p>
<p><i>[
Pete recommends editorial fix.
]</i></p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<hr>
<h3><a name="637"></a>637. [c.math]/10 inconsistent return values</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Bo Persson <b>Date:</b> 2007-02-13</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
26.7 [c.math], paragraph 10 has long lists of added signatures for float and long double
functions. All the signatures have float/long double return values, which is
inconsistent with some of the double functions they are supposed to
overload.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 26.7 [c.math], paragraph 10,
</p>
<blockquote><pre><del>float</del> <ins>int</ins> ilogb(float);
<del>float</del> <ins>long</ins> lrint(float);
<del>float</del> <ins>long</ins> lround(float);
<del>float</del> <ins>long long</ins> llrint(float);
<del>float</del> <ins>long long</ins> llround(float);
<del>long double</del> <ins>int</ins> ilogb(long double);
<del>long double</del> <ins>long</ins> lrint(long double);
<del>long double</del> <ins>long</ins> lround(long double);
<del>long double</del> <ins>long long</ins> llrint(long double);
<del>long double</del> <ins>long long</ins> llround(long double);
</pre></blockquote>
<hr>
<h3><a name="639"></a>639. Still problems with exceptions during streambuf IO</h3>
<p><b>Section:</b> 27.6.1.2.3 [istream::extractors], 27.6.2.6.3 [ostream.inserters] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-02-17</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istream::extractors">issues</a> in [istream::extractors].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
There already exist two active DR's for the wording of 27.6.1.2.3 [istream::extractors]/13
from 14882:2003(E), namely <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#413">413</a>.
</p>
<p>
Even with these proposed corrections, already maintained in N2134,
I have the feeling, that the current wording does still not properly
handle the "exceptional" situation. The combination of para 14
</p>
<blockquote><p>
"[..] Characters are extracted and inserted until
any of the following occurs:
</p>
<p>
[..]
</p>
<p>
- an exception occurs (in which case the exception is caught)."
</p></blockquote>
<p>
and 15
</p>
<blockquote><p>
"If the function inserts no characters, it calls setstate(failbit),
which
may throw ios_base::failure (27.4.4.3). If it inserted no characters
because it caught an exception thrown while extracting characters
from *this and failbit is on in exceptions() (27.4.4.3), then the
caught
exception is rethrown."
</p></blockquote>
<p>
both in N2134 seems to imply that any exception, which occurs
*after* at least one character has been inserted is caught and lost
for
ever. It seems that even if failbit is on in exceptions() rethrow is
not
allowed due to the wording "If it inserted no characters because it
caught an exception thrown while extracting".
</p>
<p>
Is this behaviour by design?
</p>
<p>
I would like to add that its output counterpart in 27.6.2.6.3 [ostream.inserters]/7-9
(also
N2134) does not demonstrate such an exception-loss-behaviour.
On the other side, I wonder concerning several subtle differences
compared to input::
</p>
<p>
1) Paragraph 8 says at its end:
</p>
<blockquote><p>
"- an exception occurs while getting a character from sb."
</p></blockquote>
<p>
Note that there is nothing mentioned which would imply that such
an exception will be caught compared to 27.6.1.2.3 [istream::extractors]/14.
</p>
<p>
2) Paragraph 9 says:
</p>
<blockquote><p>
"If the function inserts no characters, it calls setstate(failbit)
(which
may throw ios_base::failure (27.4.4.3)). If an exception was thrown
while extracting a character, the function sets failbit in error
state,
and if failbit is on in exceptions() the caught exception is
rethrown."
</p></blockquote>
<p>
The sentence starting with "If an exception was thrown" seems to
imply that such an exception *should* be caught before.
</p>
<p><b>Proposed resolution:</b></p>
<p>
(a) In 27.6.1.2.3 [istream::extractors]/15 (N2134) change the sentence
</p>
<blockquote><p>
If the function inserts no characters, it calls
<tt>setstate(failbit)</tt>, which may throw <tt>ios_base::failure</tt>
(27.4.4.3). If <del>it inserted no characters because it caught an
exception thrown while extracting characters from <tt>*this</tt></del>
<ins>an exception was thrown while extracting a character from
<tt>*this</tt>, the function sets <tt>failbit</tt> in error state,</ins>
and <tt>failbit</tt> is on in <tt>exceptions()</tt> (27.4.4.3), then the
caught exception is rethrown.
</p></blockquote>
<p>
(b) In 27.6.2.6.3 [ostream.inserters]/8 (N2134) change the sentence:
</p>
<blockquote>
<p>
Gets characters from <tt>sb</tt> and inserts them in <tt>*this</tt>.
Characters are read from <tt>sb</tt> and inserted until any of the
following occurs:
</p>
<ul>
<li>end-of-file occurs on the input sequence;</li>
<li>inserting in the output sequence fails (in which case the character to be inserted is not extracted);</li>
<li>an exception occurs while getting a character from <tt>sb</tt> <ins>(in which
case the exception is caught)</ins>.</li>
</ul>
</blockquote>
<p><b>Rationale:</b></p>
This extractor is described as a formatted input function so the
exception behavior is already specified. There is additional behavior
described in this section that applies to the case in which failbit is
set. This doesn't contradict the usual exception behavior for formatted
input functions because that applies to the case in which badbit is set.
<hr>
<h3><a name="641"></a>641. Editorial fix for 27.6.4 (N2134)</h3>
<p><b>Section:</b> 27.6.4 [ext.manip] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-02-18</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ext.manip">issues</a> in [ext.manip].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The function <tt>f</tt> in para 4 (27.6.4 [ext.manip]) references an unknown <tt>strm</tt>
in the following line:
</p>
<blockquote><pre>mg.get(Iter(str.rdbuf()), Iter(), intl, strm, err, mon);
</pre></blockquote>
<p><b>Proposed resolution:</b></p>
<p>
Change 27.6.4 [ext.manip], p4:
</p>
<blockquote><pre>mg.get(Iter(str.rdbuf()), Iter(), intl, str<del>m</del>, err, mon);
</pre></blockquote>
<p><i>[
Oxford: Editorial.
]</i></p>
<hr>
<h3><a name="642"></a>642. Invalidated fstream footnotes in N2134</h3>
<p><b>Section:</b> 27.8.1.9 [ifstream.members], 27.8.1.13 [ofstream.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-02-20</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ifstream.members">issues</a> in [ifstream.members].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The standard wording of N2134 has extended the 14882:2003(E)
wording for the ifstream/ofstream/fstream open function to fix
a long standing problem, see <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#409">409</a>.
</p>
<p>
Now it's properly written as
</p>
<blockquote><p>
"If that function does not return a null pointer calls clear(),
otherwise
calls setstate(failbit)[..]"
</p></blockquote>
<p>
instead of the previous
</p>
<blockquote><p>
"If that function returns a null pointer, calls setstate(failbit)[..]
</p></blockquote>
<p>
While the old footnotes saying
</p>
<blockquote><p>
"A successful open does not change the error state."
</p></blockquote>
<p>
where correct and important, they are invalid now for ifstream and
ofstream (because clear *does* indeed modify the error state) and
should be removed (Interestingly fstream itself never had these,
although
they where needed for that time).
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 27.8.1.9 [ifstream.members], remove footnote:
</p>
<blockquote><p>
<del><sup>334)</sup> A successful open does not change the error state.</del>
</p></blockquote>
<p>
In 27.8.1.13 [ofstream.members], remove footnote:
</p>
<blockquote><p>
<del><sup>335)</sup> A successful open does not change the error state.</del>
</p></blockquote>
<hr>
<h3><a name="647"></a>647. Inconsistent regex_search params</h3>
<p><b>Section:</b> 28.11.3 [re.alg.search] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-02-26</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
28.11.3 [re.alg.search]/5 declares
</p>
<blockquote><pre>template <class iterator, class charT, class traits>
bool regex_search(iterator first, iterator last,
const basic_regex<charT, traits>& e,
regex_constants::match_flag_type flags =
regex_constants::match_default);
</pre></blockquote>
<p>
where it's not explained, which iterator category
the parameter iterator belongs to. This is inconsistent
to the preceding declaration in the synopsis section
28.4 [re.syn], which says:
</p>
<blockquote><pre>template <class BidirectionalIterator, class charT, class traits>
bool regex_search(BidirectionalIterator first, BidirectionalIterator last,
const basic_regex<charT, traits>& e,
regex_constants::match_flag_type flags =
regex_constants::match_default);
</pre></blockquote>
<p><b>Proposed resolution:</b></p>
<p>
In 28.11.3 [re.alg.search]/5 replace all three occurences of param "iterator" with
"BidirectionalIterator"
</p>
<blockquote><pre>template <class <del>iterator</del> <ins>BidirectionalIterator</ins>, class charT, class traits>
bool regex_search(<del>iterator</del> <ins>BidirectionalIterator</ins> first, <del>iterator</del> <ins>BidirectionalIterator</ins> last,
const basic_regex<charT, traits>& e,
regex_constants::match_flag_type flags =
regex_constants::match_default);
</pre>
<p>
-6- <i>Effects:</i> Behaves "as if" by constructing an object what of
type <tt>match_results<<del>iterator</del>
<ins>BidirectionalIterator</ins>></tt> and then returning the result
of <tt>regex_search(first, last, what, e, flags)</tt>.
</p>
</blockquote>
<p><b>Rationale:</b></p>
Applied to working paper while issue was still in New status.
<hr>
<h3><a name="648"></a>648. regex_iterator c'tor needs clarification/editorial fix</h3>
<p><b>Section:</b> 28.12.1.1 [re.regiter.cnstr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-03-03</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In 28.12.1.1 [re.regiter.cnstr]/2 the effects paragraph starts with:
</p>
<blockquote>
<p>
<i>Effects:</i> Initializes begin and end to point to the beginning and the
end of the target sequence, sets pregex to &re, sets flags to f,[..]
</p></blockquote>
<p>
There are two issues with this description:
</p>
<ol>
<li>
The meaning of very first part of this quote is unclear, because
there is no target sequence provided, instead there are given two
parameters a and b, both of type BidirectionalIterator. The mentioned
part does not explain what a and b represent.
</li>
<li>
There does not exist any parameter f, but instead a parameter
m in the constructor declaration, so this is actually an editorial
fix.
</li>
</ol>
<p><b>Proposed resolution:</b></p>
<p>
In 28.12.1.1 [re.regiter.cnstr]/2 change the above quoted part by
</p>
<blockquote><p>
<i>Effects:</i> Initializes <tt>begin</tt> and <tt>end</tt> to point to
the beginning and the end of the target sequence <ins>designated by the
iterator range <tt>[a, b)</tt></ins>, sets <tt>pregex</tt> to
<tt>&re</tt>, sets <tt>flags</tt> to <tt><del>f</del>
<ins>m</ins></tt>, then calls <tt>regex_search(begin, end, match,
*pregex, flags)</tt>. If this call returns <tt>false</tt> the
constructor sets <tt>*this</tt> to the end-of-sequence iterator.
</p></blockquote>
<hr>
<h3><a name="649"></a>649. Several typos in regex_token_iterator constructors</h3>
<p><b>Section:</b> 28.12.2.1 [re.tokiter.cnstr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-03-03</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#re.tokiter.cnstr">issues</a> in [re.tokiter.cnstr].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In 28.12.2.1 [re.tokiter.cnstr]/1+2 both the constructor declaration
and the following text shows some obvious typos:
</p>
<p>
1) The third constructor form is written as
</p>
<blockquote><pre>template <std::size_t N>
regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
const regex_type& re,
const int (&submatches)[R],
regex_constants::match_flag_type m =
regex_constants::match_default);
</pre></blockquote>
<p>
where the dimensions of submatches are specified by an
unknown value R, which should be N.
</p>
<p>
2) Paragraph 2 of the same section says in its last sentence:
</p>
<blockquote><p>
The third constructor initializes the member <tt>subs</tt> to hold a
copy of the sequence of integer values pointed to by the iterator range
<tt>[&submatches, &submatches + R)</tt>.
</p></blockquote>
<p>
where again R must be replaced by N.
</p>
<p>
3) Paragraph 3 of the same section says in its first sentence:
</p>
<blockquote><p>
Each constructor then sets <tt>N</tt> to <tt>0</tt>, and
<tt>position</tt> to <tt>position_iterator(a, b, re, f)</tt>.
</p></blockquote>
<p>
where a non-existing parameter "f" is mentioned, which must be
replaced
by the parameter "m".
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 28.12.2.1 [re.tokiter.cnstr]/1:
</p>
<blockquote><pre>template <std::size_t N>
regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
const regex_type& re,
const int (&submatches)[<del>R</del> <ins>N</ins>],
regex_constants::match_flag_type m =
regex_constants::match_default);
</pre></blockquote>
<p>
Change 28.12.2.1 [re.tokiter.cnstr]/2:
</p>
<blockquote><p>
<i>Effects:</i> The first constructor initializes the member
<tt>subs</tt> to hold the single value <tt>submatch</tt>. The second
constructor initializes the member <tt>subs</tt> to hold a copy of the
argument <tt>submatches</tt>. The third constructor initializes the
member <tt>subs</tt> to hold a copy of the sequence of integer values
pointed to by the iterator range <tt>[&submatches, &submatches +
<del>R</del> <ins>N</ins>)</tt>.
</p></blockquote>
<p>
Change 28.12.2.1 [re.tokiter.cnstr]/3:
</p>
<blockquote><p>
Each constructor then sets <tt>N</tt> to <tt>0</tt>, and
<tt>position</tt> to <tt>position_iterator(a, b, re, <del>f</del>
<ins>m</ins>)</tt>. If <tt>position</tt> is not an end-of-sequence
iterator the constructor sets <tt>result</tt> to the address of the
current match. Otherwise if any of the values stored in <tt>subs</tt> is
equal to <tt>-1</tt> the constructor sets <tt>*this</tt> to a suffix
iterator that points to the range <tt>[a, b)</tt>, otherwise the
constructor sets <tt>*this</tt> to an end-of-sequence iterator.
</p></blockquote>
<hr>
<h3><a name="656"></a>656. Typo in subtract_with_carry_engine declaration</h3>
<p><b>Section:</b> 26.4.2 [rand.synopsis] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-03-08</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.synopsis">issues</a> in [rand.synopsis].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
26.4.2 [rand.synopsis] the header <tt><random></tt> synopsis
contains an unreasonable closing curly brace inside the
<tt>subtract_with_carry_engine</tt> declaration.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the current declaration in 26.4.2 [rand.synopsis]
</p>
<blockquote><pre>template <class UIntType, size_t w<del>}</del>, size_t s, size_t r>
class subtract_with_carry_engine;
</pre></blockquote>
<p><i>[
Pete: Recommends editorial.
]</i></p>
<hr>
<h3><a name="657"></a>657. unclear requirement about header inclusion</h3>
<p><b>Section:</b> 17.4.2.1 [using.headers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Gennaro Prota <b>Date:</b> 2007-03-14</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
17.4.2.1 [using.headers] states:
</p>
<blockquote><p>
A translation unit shall include a header only outside of any
external declaration or definition, [...]
</p></blockquote>
<p>
I see three problems with this requirement:
</p>
<ol type="a">
<li><p>The C++ standard doesn't define what an "external declaration" or
an "external definition" are (incidentally the C99 standard does, and
has a sentence very similar to the above regarding header inclusion).
</p><p>
I think the intent is that the #include directive shall lexically
appear outside *any* declaration; instead, when the issue was pointed
out on comp.std.c++ at least one poster interpreted "external
declaration" as "declaration of an identifier with external linkage".
If this were the correct interpretation, then the two inclusions below
would be legal:
</p>
<blockquote><pre> // at global scope
static void f()
{
# include <cstddef>
}
static void g()
{
# include <stddef.h>
}
</pre></blockquote>
<p>
(note that while the first example is unlikely to compile correctly,
the second one may well do)
</p></li>
<li><p>as the sentence stands, violations will require a diagnostic; is
this the intent? It was pointed out on comp.std.c++ (by several
posters) that at least one way to ensure a diagnostic exists:
</p>
<blockquote><p>
[If there is an actual file for each header,] one simple way
to implement this would be to insert a reserved identifier
such as __begin_header at the start of each standard header.
This reserved identifier would be ignored for all other
purposes, except that, at the appropriate point in phase 7, if
it is found inside an external definition, a diagnostic is
generated. There's many other similar ways to achieve the same
effect.
</p>
<p> --James Kuyper, on comp.std.c++
</p></blockquote></li>
<li><p>is the term "header" meant to be limited to standard headers?
Clause 17 is all about the library, but still the general question is
interesting and affects one of the points in the explicit namespaces
proposal (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1691.html">n1691</a>):
</p>
<blockquote><p>
Those seeking to conveniently enable argument-dependent
lookups for all operators within an explicit namespace
could easily create a header file that does so:
</p><pre> namespace mymath::
{
#include "using_ops.hpp"
}
</pre></blockquote>
</li>
</ol>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<p><b>Rationale:</b></p>
We believe that the existing language does not cause any real confusion
and any new formulation of the rules that we could come up with are
unlikely to be better than what's already in the standard.
<hr>
<h3><a name="658"></a>658. Two unspecified function comparators in [function.objects]</h3>
<p><b>Section:</b> 20.5 [function.objects] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Daniel Krügler <b>Date:</b> 2007-03-19</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#function.objects">issues</a> in [function.objects].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The header <tt><functional></tt> synopsis in 20.5 [function.objects]
contains the following two free comparison operator templates
for the <tt>function</tt> class template
</p>
<blockquote><pre>template<class Function1, class Function2>
void operator==(const function<Function1>&, const function<Function2>&);
template<class Function1, class Function2>
void operator!=(const function<Function1>&, const function<Function2>&);
</pre></blockquote>
<p>
which are nowhere described. I assume that they are relicts before the
corresponding two private and undefined member templates in the function
template (see 20.5.15.2 [func.wrap.func] and X [func.wrap.func.undef]) have been introduced. The original free
function templates should be removed, because using an undefined entity
would lead to an ODR violation of the user.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Remove the above mentioned two function templates from
the header <tt><functional></tt> synopsis (20.5 [function.objects])
</p>
<blockquote><pre><del>template<class Function1, class Function2>
void operator==(const function<Function1>&, const function<Function2>&);
template<class Function1, class Function2>
void operator!=(const function<Function1>&, const function<Function2>&);</del>
</pre></blockquote>
<p><b>Rationale:</b></p>
Fixed by
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2292.html">N2292</a>
Standard Library Applications for Deleted Functions.
<hr>
<h3><a name="662"></a>662. Inconsistent handling of incorrectly-placed thousands separators</h3>
<p><b>Section:</b> 22.2.2.1.2 [facet.num.get.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Cosmin Truta <b>Date:</b> 2007-04-05</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#facet.num.get.virtuals">active issues</a> in [facet.num.get.virtuals].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.num.get.virtuals">issues</a> in [facet.num.get.virtuals].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
From Section 22.2.2.1.2 [facet.num.get.virtuals], paragraphs 11 and 12, it is implied
that the value read from a stream must be stored
even if the placement of thousands separators does not conform to the
<code>grouping()</code> specification from the <code>numpunct</code> facet.
Since incorrectly-placed thousands separators are flagged as an extraction
failure (by the means of <code>failbit</code>), we believe it is better not
to store the value. A consistent strategy, in which any kind of extraction
failure leaves the input item intact, is conceptually cleaner, is able to avoid
corner-case traps, and is also more understandable from the programmer's point
of view.
</p>
<p>
Here is a quote from <i>"The C++ Programming Language (Special Edition)"</i>
by B. Stroustrup (Section D.4.2.3, pg. 897):
</p>
<blockquote><p>
<i>"If a value of the desired type could not be read, failbit is set in r.
[...] An input operator will use r to determine how to set the state of its
stream. If no error was encountered, the value read is assigned through v;
otherwise, v is left unchanged."</i>
</p></blockquote>
<p>
This statement implies that <code>rdstate()</code> alone is sufficient to
determine whether an extracted value is to be assigned to the input item
<i>val</i> passed to <code>do_get</code>. However, this is in disagreement
with the current C++ Standard. The above-mentioned assumption is true in all
cases, except when there are mismatches in digit grouping. In the latter case,
the parsed value is assigned to <i>val</i>, and, at the same time, <i>err</i>
is assigned to <code>ios_base::failbit</code> (essentially "lying" about the
success of the operation). Is this intentional? The current behavior raises
both consistency and usability concerns.
</p>
<p>
Although digit grouping is outside the scope of <code>scanf</code> (on which
the virtual methods of <code>num_get</code> are based), handling of grouping
should be consistent with the overall behavior of scanf. The specification of
<code>scanf</code> makes a distinction between input failures and matching
failures, and yet both kinds of failures have no effect on the input items
passed to <code>scanf</code>. A mismatch in digit grouping logically falls in
the category of matching failures, and it would be more consistent, and less
surprising to the user, to leave the input item intact whenever a failure is
being signaled.
</p>
<p>
The extraction of <code>bool</code> is another example outside the scope of
<code>scanf</code>, and yet consistent, even in the event of a successful
extraction of a <code>long</code> but a failed conversion from
<code>long</code> to <code>bool</code>.
</p>
<p>
Inconsistency is further aggravated by the fact that, when failbit is set,
subsequent extraction operations are no-ops until <code>failbit</code> is
explicitly cleared. Assuming that there is no explicit handling of
<code>rdstate()</code> (as in <code>cin>>i>>j</code>) it is
counter-intuitive to be able to extract an integer with mismatched digit
grouping, but to be unable to extract another, properly-formatted integer
that immediately follows.
</p>
<p>
Moreover, setting <code>failbit</code>, and selectively assigning a value to
the input item, raises usability problems. Either the strategy of
<code>scanf</code> (when there is no extracted value in case of failure), or
the strategy of the <code>strtol</code> family (when there is always an
extracted value, and there are well-defined defaults in case of a failure) are
easy to understand and easy to use. On the other hand, if <code>failbit</code>
alone cannot consistently make a difference between a failed extraction, and a
successful but not-quite-correct extraction whose output happens to be the same
as the previous value, the programmer must resort to implementation tricks.
Consider the following example:
</p>
<pre> int i = old_i;
cin >> i;
if (cin.fail())
// can the value of i be trusted?
// what does it mean if i == old_i?
// ...
</pre>
<p>
Last but not least, the current behvaior is not only confusing to the casual
reader, but it has also been confusing to some book authors. Besides
Stroustrup's book, other books (e.g. "Standard C++ IOStreams and Locales" by
Langer and Kreft) are describing the same mistaken assumption. Although books
are not to be used instead of the standard reference, the readers of these
books, as well as the people who are generally familiar to <code>scanf</code>,
are even more likely to misinterpret the standard, and expect the input items
to remain intact when a failure occurs.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 22.2.2.1.2 [facet.num.get.virtuals]:
</p>
<blockquote>
<p>
<b>Stage 3:</b> The result of stage 2 processing can be one of
</p>
<ul>
<li>A sequence of <code>chars</code> has been accumulated in stage 2 that is converted (according to the rules of <code>scanf</code>) to a value of the type of <code><i>val</i></code>. <del>This value is stored in <code><i>val</i></code> and <code>ios_base::goodbit</code> is stored in <code><i>err</i></code>.</del></li>
<li>The sequence of <code>chars</code> accumulated in stage 2 would have caused <code>scanf</code> to report an input failure. <code>ios_base::failbit</code> is assigned to <code><i>err</i></code>.</li>
</ul>
<p>
<ins>In the first case,</ins> <del>D</del><ins>d</ins>igit grouping is checked. That is, the positions of discarded separators is examined for consistency with <code>use_facet<numpunct<charT> >(<i>loc</i>).grouping()</code>. If they are not consistent then <code>ios_base::failbit</code> is assigned to <code><i>err</i></code>. <ins>Otherwise, the value that was converted in stage 2 is stored in <code><i>val</i></code> and <code>ios_base::goodbit</code> is stored in <code><i>err</i></code>.</ins>
</p>
</blockquote>
<p><b>Rationale:</b></p>
post-Toronto: Changed from New to NAD at the request of the author. The preferred solution of
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2327.pdf">N2327</a>
makes this resolution obsolete.
<hr>
<h3><a name="663"></a>663. Complexity Requirements</h3>
<p><b>Section:</b> 17.3.1.3 [structure.specifications] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>
<b>Submitter:</b> Thomas Plum <b>Date:</b> 2007-04-16</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#structure.specifications">issues</a> in [structure.specifications].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD">NAD</a> status.</p>
<p><b>Discussion:</b></p>
<p>
17.3.1.3 [structure.specifications] para 5 says
</p>
<blockquote><p>
-5- Complexity requirements specified in the library
clauses are upper bounds, and implementations that provide better
complexity guarantees satisfy the requirements.
</p></blockquote>
<p>
The following
objection has been raised:
</p>
<blockquote><p>
The library clauses suggest general
guidelines regarding complexity, but we have been unable to discover
any absolute hard-and-fast formulae for these requirements. Unless
or until the Library group standardizes specific hard-and-fast
formulae, we regard all the complexity requirements as subject to a
"fudge factor" without any intrinsic upper bound.
</p></blockquote>
<p>
[Plum ref
_23213Y31 etc]
</p>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<p><b>Rationale:</b></p>
Kona (2007): No specific instances of underspecification have been
identified, and big-O notation always involves constant factors.
<hr>
<h3><a name="683"></a>683. regex_token_iterator summary error</h3>
<p><b>Section:</b> 28.12.2 [re.tokiter] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Pending NAD Editorial</a>
<b>Submitter:</b> Eric Niebler <b>Date:</b> 2007-06-02</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#re.tokiter">issues</a> in [re.tokiter].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Pending%20NAD%20Editorial">Pending NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
28.12.2 [re.tokiter], p3 says:
</p>
<blockquote>
<p>
After it is constructed, the iterator finds and stores a value
<tt>match_results<BidirectionalIterator></tt> position and sets the
internal count <tt>N</tt> to zero.
</p>
</blockquote>
<p>
Should read:
</p>
<blockquote>
<p>
After it is constructed, the iterator finds and stores a value
<tt><del>match_results</del><ins>regex_iterator</ins><BidirectionalIterator<ins>, charT, traits</ins>></tt>
position and sets the internal count <tt>N</tt> to zero.
</p>
</blockquote>
<p><i>[
John adds:
]</i></p>
<blockquote><p>
Yep, looks like a typo/administrative fix to me.
</p></blockquote>
<p><b>Proposed resolution:</b></p>
<p>
</p>
<hr>
<h3><a name="690"></a>690. abs(long long) should return long long</h3>
<p><b>Section:</b> 26.7 [c.math] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">NAD Editorial</a>
<b>Submitter:</b> Niels Dekker <b>Date:</b> 2007-06-10</p>
<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#c.math">active issues</a> in [c.math].</p>
<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#c.math">issues</a> in [c.math].</p>
<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#NAD%20Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Quoting the latest draft (n2135), 26.7 [c.math]:
</p>
<blockquote>
<p>
The added signatures are:
</p>
<blockquote><pre>long abs(long); // labs()
long abs(long long); // llabs()
</pre></blockquote>
</blockquote>
<p>
Shouldn't <tt>abs(long long)</tt> have <tt>long long</tt> as return type?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 26.7 [c.math]:
</p>
<blockquote><pre><ins>long </ins>long abs(long long); // llabs()
</pre></blockquote>
<p><b>Rationale:</b></p>
Had already been fixed in the WP by the time the LWG reviewed this.
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