1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
2<html><head><title>C++ Standard Library Closed Issues List</title>
3
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5del {background-color:#FFFFA0}</style></head>
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8<table>
9<tbody><tr>
10<td align="left">Doc. no.</td>
11<td align="left">N2132=06-0202</td>
12</tr>
13<tr>
14<td align="left">Date:</td>
15<td align="left">2006-11-03</td>
16</tr>
17<tr>
18<td align="left">Project:</td>
19<td align="left">Programming Language C++</td>
20</tr>
21<tr>
22<td align="left">Reply to:</td>
23<td align="left">Howard Hinnant &lt;howard.hinnant@gmail.com&gt;</td>
24</tr>
25</tbody></table>
26<h1>C++ Standard Library Closed Issues List (Revision R45)</h1>
27  <p>Reference ISO/IEC IS 14882:1998(E)</p>
28  <p>Also see:</p>
29    <ul>
30      <li>
31<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-toc.html">Table of Contents</a> for all library issues.</li>
32      <li>
33<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html">Index by Section</a> for all library issues.</li>
34      <li>
35<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html">Index by Status</a> for all library issues.</li>
36      <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html">Library Active Issues List</a></li>
37      <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html">Library Defect Reports List</a></li>
38    </ul>
39
40  <p>This document contains only library issues which have been closed
41  by the Library Working Group as duplicates or not defects. That is,
42  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
43  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
44  defects.  The introductory material in that document also applies to
45  this document.</p>
46<h2>Revision History</h2>
47<ul>
48<li>R45:
492006-11-03 post-Portland mailing.
50Moved 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.
51Moved 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.
52Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Dup.
53Moved 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-active.html#524">524</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.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-active.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.
54Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.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-active.html#598">598</a> - <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#605">605</a> to Ready.
55Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#604">604</a> to Review.
56Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#593">593</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#609">609</a>.
57</li>
58<li>R44:
592006-09-08 pre-Portland mailing.
60Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#583">583</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#592">592</a>.
61</li>
62<li>R43:
632006-06-23 mid-term mailing.
64Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#575">575</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#582">582</a>.
65Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#255">255</a>.
66Moved 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.
67</li>
68<li>R42:
692006-04-21 post-Berlin mailing.
70Added 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-active.html#572">572</a>.
71Moved 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.
72Moved 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-active.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-active.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-active.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.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-active.html#548">548</a> to Open.
73Moved 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-active.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.
74Moved 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.
75Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#534">534</a> to Review.
76</li>
77<li>R41:
782006-02-24 pre-Berlin mailing.
79Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#536">536</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#566">566</a>.
80Moved <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#342">342</a> from Ready to Open.
81Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#309">309</a>.
82</li>
83<li>R40:
842005-12-16 mid-term mailing.
85Added 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>.
86</li>
87<li>R39:
882005-10-14 post-Mont Tremblant mailing.
89Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#526">526</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#528">528</a>.
90Moved 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.
91Moved 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.
92Moved 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.
93Moved 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.
94Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#500">500</a> from New to NAD.
95Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#518">518</a> from New to Review.
96</li>
97<li>R38:
982005-07-03 pre-Mont Tremblant mailing.
99Merged 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>.
100Added 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>
101</li>
102<li>R37:
1032005-06 mid-term mailing.
104Added 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>.
105</li>
106<li>R36:
1072005-04 post-Lillehammer mailing. All issues in "ready" status except
108for <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
109previously in "DR" status were moved to "WP".
110</li>
111<li>R35:
1122005-03 pre-Lillehammer mailing.
113</li>
114<li>R34:
1152005-01 mid-term mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#488">488</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#494">494</a>.
116</li>
117<li>R33:
1182004-11 post-Redmond mailing. Reflects actions taken in Redmond.
119</li>
120<li>R32:
1212004-09 pre-Redmond mailing: reflects new proposed resolutions and
122new issues received after the 2004-07 mailing.  Added
123new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#479">479</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#481">481</a>.
124</li>
125<li>R31:
1262004-07 mid-term mailing: reflects new proposed resolutions and
127new issues received after the post-Sydney mailing.  Added
128new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#463">463</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>.
129</li>
130<li>R30:
131Post-Sydney mailing: reflects decisions made at the Sydney meeting.
132Voted all "Ready" issues from R29 into the working paper.
133Added 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>.
134</li>
135<li>R29:
136Pre-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>.
137</li>
138<li>R28:
139Post-Kona mailing: reflects decisions made at the Kona meeting.
140Added 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>.
141</li>
142<li>R27:
143Pre-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>.
144</li>
145<li>R26:
146Post-Oxford mailing: reflects decisions made at the Oxford meeting.
147All issues in Ready status were voted into DR status.  All issues in
148DR status were voted into WP status.
149</li>
150<li>R25:
151Pre-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>.
152</li>
153<li>R24:
154Post-Santa Cruz mailing: reflects decisions made at the Santa Cruz
155meeting.  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
156moved 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
157at 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
158concerns with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a> involve wording.
159</li>
160<li>R23:
161Pre-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>.
162Moved issues in the TC to TC status.
163</li>
164<li>R22:
165Post-Cura�ao 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>.
166</li>
167<li>R21:
168Pre-Cura�ao 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>.
169</li>
170<li>R20:
171Post-Redmond mailing; reflects actions taken in Redmond.  Added
172new 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
173<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
174not discussed at the meeting.
175
176All Ready issues were moved to DR status, with the exception of issues
177<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>.
178
179Noteworthy issues discussed at Redmond include
180<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-active.html#233">233</a>,
181<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-active.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>.
182</li>
183<li>R19:
184Pre-Redmond mailing.  Added new issues
185<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>.
186</li>
187<li>R18:
188Post-Copenhagen mailing; reflects actions taken in Copenhagen.
189Added 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
190new 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>.
191
192Changed status of issues
193<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>
194<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>
195<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>
196<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>
197<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>
198<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>
199<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#268">268</a>
200to DR.
201
202Changed status of issues
203<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>
204<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>
205<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>
206<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>
207<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>
208<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>
209<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>
210<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>
211<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>
212to Ready.
213
214Closed issues
215<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>
216<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>
217<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a>
218as NAD.
219
220</li>
221<li>R17:
222Pre-Copenhagen mailing.  Converted issues list to XML.  Added proposed
223resolutions 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>.
224Added 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>.
225</li>
226<li>R16:
227post-Toronto mailing; reflects actions taken in Toronto. Added new
228issues <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
229<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>,
230<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>,
231<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>,
232<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>,
233<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>,
234<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>,
235<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>,
236<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>,
237<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>,
238<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>,
239<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>,
240<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>,
241<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
242issue <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
243<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
244issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#70">70</a>: signature should be changed both places it
245appears. Fixed issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#160">160</a>: previous version didn't fix
246the bug in enough places.
247</li>
248<li>R15:
249pre-Toronto mailing. Added issues
250<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.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
251changes so that we pass Weblint tests.
252</li>
253<li>R14:
254post-Tokyo II mailing; reflects committee actions taken in
255Tokyo. 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)
256</li>
257<li>R13:
258pre-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>.
259</li>
260<li>R12:
261pre-Tokyo II mailing: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a> to
262<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
263of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#29">29</a>.  Add further rationale to issue
264<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#178">178</a>.
265</li>
266<li>R11:
267post-Kona mailing: Updated to reflect LWG and full committee actions
268in Kona (99-0048/N1224). Note changed resolution of issues
269<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>
270to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198">198</a>. Closed issues list split into "defects" and
271"closed" documents.  Changed the proposed resolution of issue
272<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
273of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>.
274</li>
275<li>R10:
276pre-Kona updated.  Added proposed resolutions <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>,
277<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>,
278<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
279<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#195">195</a>. (99-0033/D1209, 14 Oct 99)
280</li>
281<li>R9:
282pre-Kona mailing.  Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a> to
283<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#189">189</a>. Issues list split into separate "active" and
284"closed" documents. (99-0030/N1206, 25 Aug 99)
285</li>
286<li>R8:
287post-Dublin mailing. Updated to reflect LWG and full committee actions
288in Dublin. (99-0016/N1193, 21 Apr 99)
289</li>
290<li>R7:
291pre-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>,
292<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>,
293<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>,
294<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)
295</li>
296<li>R6:
297pre-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>,
298and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>.  (99-0007/N1194, 22 Feb 99)
299</li>
300<li>R5:
301update 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
302<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
303for making list public. (30 Dec 98)
304</li>
305<li>R4:
306post-Santa Cruz II updated: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#110">110</a>,
307<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
308issues corrected. (22 Oct 98)
309</li>
310<li>R3:
311post-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>
312added, many issues updated to reflect LWG consensus (12 Oct 98)
313</li>
314<li>R2:
315pre-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,
316issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a> updated. (29 Sep 98)
317</li>
318<li>R1:
319Correction 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
320format, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a> title. (17 Sep 98)
321</li>
322</ul>
323<h2>Closed Issues</h2>
324<hr>
325<a name="2"><h3>2.&nbsp;Auto_ptr conversions effects incorrect</h3></a><p><b>Section:</b>&nbsp;20.4.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary.prop"> [lib.meta.unary.prop]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;4 Dec 1997</p>
326<p>Paragraph 1 in "Effects", says "Calls
327p-&gt;release()" where it clearly must be "Calls
328p.release()". (As it is, it seems to require using
329auto_ptr&lt;&gt;::operator-&gt; to refer to X::release, assuming that
330exists.)</p>
331<p><b>Proposed resolution:</b></p>
332<p>Change 20.4.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary.prop"> [lib.meta.unary.prop]</a> paragraph 1 Effects from
333"Calls p-&gt;release()" to "Calls p.release()".</p>
334<p><b>Rationale:</b></p>
335<p>Not a defect: the proposed change is already found in the standard.
336[Originally classified as a defect, later reclassified.]</p>
337<hr>
338<a name="4"><h3>4.&nbsp;Basic_string size_type and difference_type should be implementation defined</h3></a><p><b>Section:</b>&nbsp;21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;16 Nov 1997</p>
339<p>In Morristown we changed the size_type and difference_type typedefs
340for all the other containers to implementation defined with a
341reference to 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>.  This should probably also have been
342done for strings. </p>
343<p><b>Proposed resolution:</b></p>
344<p><b>Rationale:</b></p>
345<p>Not a defect.  [Originally classified as a defect, later
346reclassified.]  basic_string, unlike the other standard library
347template containers, is severely constrained by its use of
348char_traits. Those types are dictated by the traits class, and are far
349from implementation defined.</p>
350<hr>
351<a name="6"><h3>6.&nbsp;File position not an offset unimplementable</h3></a><p><b>Section:</b>&nbsp;27.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos"> [lib.fpos]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;15 Dec 1997</p>
352<p>Table 88, in I/O, is too strict; it's unimplementable on systems
353where a file position isn't just an offset. It also never says just
354what fpos&lt;&gt; is really supposed to be.  [Here's my summary, which
355Jerry agrees is more or less accurate. "I think I now know what
356the class really is, at this point: it's a magic cookie that
357encapsulates an mbstate_t and a file position (possibly represented as
358an fpos_t), it has syntactic support for pointer-like arithmetic, and
359implementors are required to have real, not just syntactic, support
360for arithmetic." This isn't standardese, of course.] </p>
361<p><b>Proposed resolution:</b></p>
362<p><b>Rationale:</b></p>
363<p>Not a defect. The LWG believes that the Standard is already clear,
364and that the above summary is what the Standard in effect says.</p>
365<hr>
366<a name="10"><h3>10.&nbsp;Codecvt&lt;&gt;::do unclear</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;14 Jan 1998</p>
367<p>Section 22.2.1.5.2 says that codecvt&lt;&gt;::do_in and do_out
368should return the value noconv if "no conversion was
369needed". However, I don't see anything anywhere that defines what
370it means for a conversion to be needed or not needed. I can think of
371several circumstances where one might plausibly think that a
372conversion is not "needed", but I don't know which one is
373intended here. </p>
374<p><b>Proposed resolution:</b></p>
375<p><b>Rationale:</b></p>
376<p>Duplicate. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#19">19</a>.</p>
377<hr>
378<a name="12"><h3>12.&nbsp;Way objects hold allocators unclear</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;23 Feb 1998</p>
379<p>I couldn't find a statement in the standard saying whether the allocator object held by
380a container is held as a copy of the constructor argument or whether a pointer of
381reference is maintained internal. There is an according statement for compare objects and
382how they are maintained by the associative containers, but I couldn't find anything
383regarding allocators. </p>
384
385<p>Did I overlook it? Is it an open issue or known defect? Or is it deliberately left
386unspecified? </p>
387<p><b>Proposed resolution:</b></p>
388<p><b>Rationale:</b></p>
389<p>Not a defect. The LWG believes that the Standard is already
390clear.&nbsp; See 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>, paragraph 8.</p>
391<hr>
392<a name="43"><h3>43.&nbsp;Locale table correction</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Brendan Kehoe&nbsp; <b>Date:</b>&nbsp;1 Jun 1998</p>
393<p><b>Proposed resolution:</b></p>
394<p><b>Rationale:</b></p>
395<p>Duplicate. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#33">33</a>.</p>
396<hr>
397<a name="45"><h3>45.&nbsp;Stringstreams read/write pointers initial position unclear</h3></a><p><b>Section:</b>&nbsp;27.7.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostringstream"> [lib.ostringstream]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matthias Mueller&nbsp; <b>Date:</b>&nbsp;27 May 1998</p>
398<p>In a comp.lang.c++.moderated Matthias Mueller wrote:</p>
399
400<p>"We are not sure how to interpret the CD2 (see 27.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.forward"> [lib.iostream.forward]</a>, 27.7.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostringstream.cons"> [lib.ostringstream.cons]</a>, 27.7.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.cons"> [lib.stringbuf.cons]</a>)
401with respect to the question as to what the correct initial positions
402of the write and&nbsp; read pointers of a stringstream should
403be."</p>
404
405<p>"Is it the same to output two strings or to initialize the stringstream with the
406first and to output the second?"</p>
407
408<p><i>[PJ Plauger, Bjarne Stroustrup, Randy Smithey, Sean Corfield, and
409Jerry Schwarz have all offered opinions; see reflector messages
410lib-6518, 6519, 6520, 6521, 6523, 6524.]</i></p>
411
412<p><b>Proposed resolution:</b></p>
413<p><b>Rationale:</b></p>
414<p>The LWG believes the Standard is correct as written. The behavior
415of stringstreams is consistent with fstreams, and there is a
416constructor which can be used to obtain the desired effect. This
417behavior is known to be different from strstreams.</p>
418<hr>
419<a name="58"><h3>58.&nbsp;Extracting a char from a wide-oriented stream</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;1 Jul 1998</p>
420<p>27.6.1.2.3 has member functions for extraction of signed char and
421unsigned char, both singly and as strings. However, it doesn't say
422what it means to extract a <tt>char</tt> from a
423<tt>basic_streambuf&lt;charT, Traits&gt;</tt>. </p>
424
425<p>basic_streambuf, after all, has no members to extract a char, so
426basic_istream must somehow convert from charT to signed char or
427unsigned char. The standard doesn't say how it is to perform that
428conversion. </p>
429<p><b>Proposed resolution:</b></p>
430<p><b>Rationale:</b></p>
431<p>The Standard is correct as written.  There is no such extractor and
432this is the intent of the LWG.</p>
433<hr>
434<a name="65"><h3>65.&nbsp;Underspecification of strstreambuf::seekoff</h3></a><p><b>Section:</b>&nbsp;D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;18 Aug 1998</p>
435<p>The standard says how this member function affects the current
436stream position. (<tt>gptr</tt> or <tt>pptr</tt>) However, it does not
437say how this member function affects the beginning and end of the
438get/put area. </p>
439
440<p>This is an issue when seekoff is used to position the get pointer
441beyond the end of the current read area. (Which is legal. This is
442implicit in the definition of <i>seekhigh</i> in D.7.1, paragraph 4.)
443</p>
444<p><b>Proposed resolution:</b></p>
445<p><b>Rationale:</b></p>
446<p>The LWG agrees that seekoff() is underspecified, but does not wish
447to invest effort in this deprecated feature.</p>
448<hr>
449<a name="67"><h3>67.&nbsp;Setw useless for strings</h3></a><p><b>Section:</b>&nbsp;21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;9 Jul 1998</p>
450<p>In a comp.std.c++ posting Michel Michaud wrote: What
451should be output by: </p>
452
453<pre>   string text("Hello");
454   cout &lt;&lt; '[' &lt;&lt; setw(10) &lt;&lt; right &lt;&lt; text &lt;&lt; ']';
455</pre>
456
457<p>Shouldn't it be:</p>
458
459<pre>   [     Hello]</pre>
460
461<p>Another person replied: Actually, according to the FDIS, the width
462of the field should be the minimum of width and the length of the
463string, so the output shouldn't have any padding. I think that this is
464a typo, however, and that what is wanted is the maximum of the
465two. (As written, setw is useless for strings. If that had been the
466intent, one wouldn't expect them to have mentioned using its value.)
467</p>
468
469<p>It's worth pointing out that this is a recent correction anyway;
470IIRC, earlier versions of the draft forgot to mention formatting
471parameters whatsoever.</p>
472<p><b>Proposed resolution:</b></p>
473<p><b>Rationale:</b></p>
474<p>Duplicate. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#25">25</a>.</p>
475<hr>
476<a name="72"><h3>72.&nbsp;Do_convert phantom member function</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;24 Aug 1998</p>
477<p>In 22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a> par 3, and in <font color="red">22.2.1.5.2</font> par 8, a nonexistent member function
478"do_convert" is mentioned. This member was replaced with
479"do_in" and "do_out", the proper referents in the
480contexts above.</p>
481<p><b>Proposed resolution:</b></p>
482<p><b>Rationale:</b></p>
483<p>Duplicate: see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#24">24</a>.</p>
484<hr>
485<a name="73"><h3>73.&nbsp;<tt>is_open</tt> should be const</h3></a><p><b>Section:</b>&nbsp;27.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstreams"> [lib.fstreams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;27 Aug 1998</p>
486<p>Classes <tt>basic_ifstream</tt>, <tt>basic_ofstream</tt>, and
487<tt>basic_fstream</tt> all have a member function <tt>is_open</tt>. It
488should be a <tt>const</tt> member function, since it does nothing but
489call one of <tt>basic_filebuf</tt>'s const member functions. </p>
490<p><b>Proposed resolution:</b></p>
491<p><b>Rationale:</b></p>
492<p>Not a defect. This is a deliberate feature; const streams would be
493meaningless.</p>
494<hr>
495<a name="77"></a><h3><a name="77">77.&nbsp;Valarray operator[] const returning value</a></h3><p><b>Section:</b>&nbsp;26.5.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.valarray.access"> [lib.valarray.access]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Levente Farkas&nbsp; <b>Date:</b>&nbsp;9 Sep 1998</p>
496<p>valarray:<br>
497<br>
498&nbsp;&nbsp;&nbsp; <tt>T operator[] (size_t) const;</tt><br>
499<br>
500why not <br>
501<br>
502&nbsp;&nbsp;&nbsp; <tt>const T&amp; operator[] (size_t) const;</tt><br>
503<br>
504as in vector ???<br>
505<br>
506One can't copy even from a const valarray eg:<br>
507<br>
508&nbsp;&nbsp;&nbsp; <tt>memcpy(ptr, &amp;v[0], v.size() * sizeof(double));<br>
509</tt><br>
510[I] find this bug in valarray is very difficult.</p>
511<p><b>Proposed resolution:</b></p>
512<p><b>Rationale:</b></p>
513<p>The LWG believes that the interface was deliberately designed that
514way. That is what valarray was designed to do; that's where the
515"value array" name comes from. LWG members further comment
516that "we don't want valarray to be a full STL container."
51726.5.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.valarray.access"> [lib.valarray.access]</a> specifies properties that indicate "an
518absence of aliasing" for non-constant arrays; this allows
519optimizations, including special hardware optimizations, that are not
520otherwise possible. </p>
521<hr>
522<a name="81"><h3>81.&nbsp;Wrong declaration of slice operations</h3></a><p><b>Section:</b>&nbsp;26.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.member.ops"> [lib.complex.member.ops]</a>, 26.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.value.ops"> [lib.complex.value.ops]</a>, 26.3.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.transcendentals"> [lib.complex.transcendentals]</a>, 26.3.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.cmplx.over"> [lib.cmplx.over]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
523<p>Isn't the definition of copy constructor and assignment operators wrong?
524&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Instead of</p>
525
526<pre>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; slice_array(const slice_array&amp;);
527&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; slice_array&amp; operator=(const slice_array&amp;);</pre>
528
529<p>IMHO they have to be</p>
530
531<pre>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;slice_array(const slice_array&lt;T&gt;&amp;);
532&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;slice_array&amp; operator=(const slice_array&lt;T&gt;&amp;);</pre>
533
534<p>Same for gslice_array. </p>
535<p><b>Proposed resolution:</b></p>
536<p><b>Rationale:</b></p>
537<p>Not a defect. The Standard is correct as written. </p>
538<hr>
539<a name="82"><h3>82.&nbsp;Missing constant for set elements</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
540<p>Paragraph 5 specifies:</p>
541
542<blockquote>
543For set and multiset the value type is the same as the key type. For
544map and multimap it is equal to pair&lt;const Key, T&gt;.
545</blockquote>
546
547<p>Strictly speaking, this is not correct because for set and multiset
548the value type is the same as the <b>constant</b> key type.</p>
549<p><b>Proposed resolution:</b></p>
550<p><b>Rationale:</b></p>
551<p>Not a defect. The Standard is correct as written; it uses a
552different mechanism (const &amp;) for <tt>set</tt> and
553<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
554issue.</p>
555<hr>
556<a name="84"><h3>84.&nbsp;Ambiguity with string::insert()</h3></a><p><b>Section:</b>&nbsp;21.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.modifiers"> [lib.string.modifiers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
557<p>If I try</p>
558<pre>    s.insert(0,1,' ');</pre>
559
560<p>&nbsp; I get an nasty ambiguity. It might be</p>
561<pre>    s.insert((size_type)0,(size_type)1,(charT)' ');</pre>
562
563<p>which inserts 1 space character at position 0, or</p>
564<pre>    s.insert((char*)0,(size_type)1,(charT)' ')</pre>
565
566<p>which inserts 1 space character at iterator/address 0 (bingo!), or</p>
567<pre>    s.insert((char*)0, (InputIterator)1, (InputIterator)' ')</pre>
568
569<p>which normally inserts characters from iterator 1 to iterator '
570'. But according to 23.1.1.9 (the "do the right thing" fix)
571it is equivalent to the second. However, it is still ambiguous,
572because of course I mean the first!</p>
573<p><b>Proposed resolution:</b></p>
574<p><b>Rationale:</b></p>
575<p>Not a defect. The LWG believes this is a "genetic
576misfortune" inherent in the design of string and thus not a
577defect in the Standard as such .</p>
578<hr>
579<a name="85"><h3>85.&nbsp;String char types</h3></a><p><b>Section:</b>&nbsp;21 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.strings"> [lib.strings]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
580<p>The standard seems not to require that charT is equivalent to
581traits::char_type. So, what happens if charT is not equivalent to
582traits::char_type?</p>
583<p><b>Proposed resolution:</b></p>
584<p><b>Rationale:</b></p>
585<p>There is already wording in 21.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits"> [lib.char.traits]</a> paragraph 3 that
586requires them to be the same.</p>
587<hr>
588<a name="87"><h3>87.&nbsp;Error in description of string::compare()</h3></a><p><b>Section:</b>&nbsp;21.3.6.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::compare"> [lib.string::compare]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
589<p>The following compare() description is obviously a bug:</p>
590
591<pre>int compare(size_type pos, size_type n1,
592            charT *s, size_type n2 = npos) const;
593</pre>
594
595<p>because without passing n2 it should compare up to the end of the
596string instead of comparing npos characters (which throws an
597exception) </p>
598<p><b>Proposed resolution:</b></p>
599<p><b>Rationale:</b></p>
600<p>Duplicate; see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#5">5</a>.</p>
601<hr>
602<a name="88"><h3>88.&nbsp;Inconsistency between string::insert() and string::append()</h3></a><p><b>Section:</b>&nbsp;21.3.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::insert"> [lib.string::insert]</a>, 21.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::append"> [lib.string::append]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
603<p>Why does </p>
604<pre>  template&lt;class InputIterator&gt;
605       basic_string&amp; append(InputIterator first, InputIterator last);</pre>
606
607<p>return a string, while</p>
608<pre>  template&lt;class InputIterator&gt;
609       void insert(iterator p, InputIterator first, InputIterator last);</pre>
610
611<p>returns nothing ?</p>
612<p><b>Proposed resolution:</b></p>
613<p><b>Rationale:</b></p>
614<p>The LWG believes this stylistic inconsistency is not sufficiently
615serious to constitute a defect.</p>
616<hr>
617<a name="89"><h3>89.&nbsp;Missing throw specification for string::insert() and string::replace()</h3></a><p><b>Section:</b>&nbsp;21.3.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::insert"> [lib.string::insert]</a>, 21.3.5.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::replace"> [lib.string::replace]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
618<p>All insert() and replace() members for strings with an iterator as
619first argument lack a throw specification. The throw
620specification should probably be: length_error if size exceeds
621maximum. </p>
622<p><b>Proposed resolution:</b></p>
623<p><b>Rationale:</b></p>
624<p>Considered a duplicate because it will be solved by the resolution
625of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>.</p>
626<hr>
627<a name="93"><h3>93.&nbsp;Incomplete Valarray Subset Definitions</h3></a><p><b>Section:</b>&nbsp;26.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.numbers"> [lib.complex.numbers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
628<p>You can easily create subsets, but you can't easily combine them
629with other subsets.  Unfortunately, you almost always needs an
630explicit type conversion to valarray. This is because the standard
631does not specify that valarray subsets provide the same operations as
632valarrays. </p>
633
634<p>For example, to multiply two subsets and assign the result to a third subset, you can't
635write the following:</p>
636
637<pre>va[slice(0,4,3)] = va[slice(1,4,3)] * va[slice(2,4,3)];</pre>
638
639<p>Instead, you have to code as follows:</p>
640
641<pre>va[slice(0,4,3)] = static_cast&lt;valarray&lt;double&gt; &gt;(va[slice(1,4,3)]) *
642                   static_cast&lt;valarray&lt;double&gt; &gt;(va[slice(2,4,3)]);</pre>
643
644<p>This is tedious and error-prone. Even worse, it costs performance because each cast
645creates a temporary objects, which could be avoided without the cast. </p>
646<p><b>Proposed resolution:</b></p>
647<p>Extend all valarray subset types so that they offer all valarray operations.</p>
648<p><b>Rationale:</b></p>
649<p>This is not a defect in the Standard; it is a request for an extension.</p>
650<hr>
651<a name="94"><h3>94.&nbsp;May library implementors add template parameters to Standard Library classes?</h3></a><p><b>Section:</b>&nbsp;17.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.conforming"> [lib.conforming]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;22 Jan 1998</p>
652<p>Is it a permitted extension for library implementors to add template parameters to
653standard library classes, provided that those extra parameters have defaults? For example,
654instead of defining <tt>template &lt;class T, class Alloc = allocator&lt;T&gt; &gt; class
655vector;</tt> defining it as <tt>template &lt;class T, class Alloc = allocator&lt;T&gt;,
656int N = 1&gt; class vector;</tt> </p>
657
658<p>The standard may well already allow this (I can't think of any way that this extension
659could break a conforming program, considering that users are not permitted to
660forward-declare standard library components), but it ought to be explicitly permitted or
661forbidden. </p>
662
663<p>comment from Steve Cleary via comp.std.c++:</p>
664<blockquote>
665<p>I disagree [with the proposed resolution] for the following reason:
666consider user library code with template template parameters. For
667example, a user library object may be templated on the type of
668underlying sequence storage to use (deque/list/vector), since these
669classes all take the same number and type of template parameters; this
670would allow the user to determine the performance tradeoffs of the
671user library object. A similar example is a user library object
672templated on the type of underlying set storage (set/multiset) or map
673storage (map/multimap), which would allow users to change (within
674reason) the semantic meanings of operations on that object.</p>
675<p>I think that additional template parameters should be forbidden in
676the Standard classes. Library writers don't lose any expressive power,
677and can still offer extensions because additional template parameters
678may be provided by a non-Standard implementation class:</p>
679<pre>
680   template &lt;class T, class Allocator = allocator&lt;T&gt;, int N = 1&gt;
681   class __vector
682   { ... };
683   template &lt;class T, class Allocator = allocator&lt;T&gt; &gt;
684   class vector: public __vector&lt;T, Allocator&gt;
685   { ... };
686</pre>
687
688</blockquote>
689
690<p><b>Proposed resolution:</b></p>
691<p>Add a new subclause [presumably 17.4.4.9] following 17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a>:</p>
692
693<blockquote>
694  <p>17.4.4.9 Template Parameters</p> <p>A specialization of a
695  template class described in the C++ Standard Library behaves the
696  same as if the implementation declares no additional template
697  parameters.</p> <p>Footnote: Additional template parameters with
698  default values are thus permitted.</p>
699</blockquote>
700
701<p>Add "template parameters" to the list of subclauses at
702the end of 17.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.conforming"> [lib.conforming]</a> paragraph 1.</p>
703
704<p><i>[Kona: The LWG agreed the standard needs clarification. After
705discussion with John Spicer, it seems added template parameters can be
706detected by a program using template-template parameters. A straw vote
707- "should implementors be allowed to add template
708parameters?" found no consensus ; 5 - yes, 7 - no.]</i></p>
709
710<p><b>Rationale:</b></p>
711<p>
712There is no ambiguity; the standard is clear as written.  Library
713implementors are not permitted to add template parameters to standard
714library classes.  This does not fall under the "as if" rule,
715so it would be permitted only if the standard gave explicit license
716for implementors to do this.  This would require a change in the
717standard.
718</p>
719
720<p>
721The LWG decided against making this change, because it would break
722user code involving template template parameters or specializations
723of standard library class templates.
724</p>
725<hr>
726<a name="95"><h3>95.&nbsp;Members added by the implementation</h3></a><p><b>Section:</b>&nbsp;17.4.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.member.functions"> [lib.member.functions]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
727<p>In 17.3.4.4/2 vs 17.3.4.7/0 there is a hole; an implementation could add virtual
728members a base class and break user derived classes.</p>
729
730<p>Example: </p>
731
732<blockquote>
733  <pre>// implementation code:
734struct _Base { // _Base is in the implementer namespace
735        virtual void foo ();
736};
737class vector : _Base // deriving from a class is allowed
738{ ... };
739
740// user code:
741class vector_checking : public vector
742{
743        void foo (); // don't want to override _Base::foo () as the
744                     // user doesn't know about _Base::foo ()
745};</pre>
746</blockquote>
747<p><b>Proposed resolution:</b></p>
748<p>Clarify the wording to make the example illegal.</p>
749<p><b>Rationale:</b></p>
750<p>This is not a defect in the Standard.&nbsp; The example is already
751illegal.&nbsp; See 17.4.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.member.functions"> [lib.member.functions]</a> paragraph 2.</p>
752<hr>
753<a name="97"><h3>97.&nbsp;Insert inconsistent definition</h3></a><p><b>Section:</b>&nbsp;23 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.containers"> [lib.containers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
754<p><tt>insert(iterator, const value_type&amp;)</tt> is defined both on
755sequences and on set, with unrelated semantics: insert here (in
756sequences), and insert with hint (in associative containers). They
757should have different names (B.S. says: do not abuse overloading).</p>
758<p><b>Proposed resolution:</b></p>
759<p><b>Rationale:</b></p>
760<p>This is not a defect in the Standard. It is a genetic misfortune of
761the design, for better or for worse.</p>
762<hr>
763<a name="99"><h3>99.&nbsp;Reverse_iterator comparisons completely wrong</h3></a><p><b>Section:</b>&nbsp;24.4.1.3.13 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.op=="> [lib.reverse.iter.op==]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
764<p>The &lt;, &gt;, &lt;=, &gt;= comparison operator are wrong: they
765return the opposite of what they should.</p>
766
767<p>Note: same problem in CD2, these were not even defined in CD1.  SGI
768STL code is correct; this problem is known since the Morristown
769meeting but there it was too late</p>
770<p><b>Proposed resolution:</b></p>
771<p><b>Rationale:</b></p>
772<p>This is not a defect in the Standard. A careful reading shows the Standard is correct
773as written. A review of several implementations show that they implement
774exactly what the Standard says.</p>
775<hr>
776<a name="100"><h3>100.&nbsp;Insert iterators/ostream_iterators overconstrained</h3></a><p><b>Section:</b>&nbsp;24.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.insert.iterators"> [lib.insert.iterators]</a>, 24.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.ostreambuf.iterator"> [lib.ostreambuf.iterator]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
777<p>Overspecified For an insert iterator it, the expression *it is
778required to return a reference to it. This is a simple possible
779implementation, but as the SGI STL documentation says, not the only
780one, and the user should not assume that this is the case.</p>
781<p><b>Proposed resolution:</b></p>
782<p><b>Rationale:</b></p>
783<p>The LWG believes this causes no harm and is not a defect in the
784standard. The only example anyone could come up with caused some
785incorrect code to work, rather than the other way around.</p>
786<hr>
787<a name="101"><h3>101.&nbsp;No way to free storage for vector and deque</h3></a><p><b>Section:</b>&nbsp;23.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a>, 23.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.array"> [lib.array]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
788<p>Reserve can not free storage, unlike string::reserve</p>
789<p><b>Proposed resolution:</b></p>
790<p><b>Rationale:</b></p>
791<p>This is not a defect in the Standard. The LWG has considered this
792issue in the past and sees no need to change the Standard. Deque has
793no reserve() member function. For vector, shrink-to-fit can be
794expressed in a single line of code (where <tt>v</tt> is
795<tt>vector&lt;T&gt;</tt>):
796</p>
797
798<blockquote>
799  <p><tt>vector&lt;T&gt;(v).swap(v);&nbsp; // shrink-to-fit v</tt></p>
800</blockquote>
801<hr>
802<a name="102"><h3>102.&nbsp;Bug in insert range in associative containers</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
803<p>Table 69 of Containers say that a.insert(i,j) is linear if [i, j) is ordered. It seems
804impossible to implement, as it means that if [i, j) = [x], insert in an associative
805container is O(1)!</p>
806<p><b>Proposed resolution:</b></p>
807<p>N+log (size()) if [i,j) is sorted according to value_comp()</p>
808<p><b>Rationale:</b></p>
809<p>Subsumed by issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a>.</p>
810<hr>
811<a name="104"><h3>104.&nbsp;Description of basic_string::operator[] is unclear</h3></a><p><b>Section:</b>&nbsp;21.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.access"> [lib.string.access]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
812<p>It is not clear that undefined behavior applies when pos == size ()
813for the non const version.</p>
814<p><b>Proposed resolution:</b></p>
815<p>Rewrite as: Otherwise, if pos &gt; size () or pos == size () and
816the non-const version is used, then the behavior is undefined.</p>
817<p><b>Rationale:</b></p>
818<p>The Standard is correct. The proposed resolution already appears in
819the Standard.</p>
820<hr>
821<a name="105"><h3>105.&nbsp;fstream ctors argument types desired</h3></a><p><b>Section:</b>&nbsp;27.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.file.streams"> [lib.file.streams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
822<p>fstream ctors take a const char* instead of string.<br>
823fstream ctors can't take wchar_t</p>
824
825<p>An extension to add a const wchar_t* to fstream would make the
826implementation non conforming.</p>
827<p><b>Proposed resolution:</b></p>
828<p><b>Rationale:</b></p>
829<p>This is not a defect in the Standard. It might be an
830interesting extension for the next Standard. </p>
831<hr>
832<a name="107"><h3>107.&nbsp;Valarray constructor is strange</h3></a><p><b>Section:</b>&nbsp;26.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex"> [lib.complex]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
833<p>The order of the arguments is (elem, size) instead of the normal
834(size, elem) in the rest of the library. Since elem often has an
835integral or floating point type, both types are convertible to each
836other and reversing them leads to a well formed program.</p>
837<p><b>Proposed resolution:</b></p>
838<p>Inverting the arguments could silently break programs. Introduce
839the two signatures (const T&amp;, size_t) and (size_t, const T&amp;),
840but make the one we do not want private so errors result in a
841diagnosed access violation. This technique can also be applied to STL
842containers.</p>
843<p><b>Rationale:</b></p>
844<p>The LWG believes that while the order of arguments is unfortunate,
845it does not constitute a defect in the standard. The LWG believes that
846the proposed solution will not work for valarray&lt;size_t&gt; and
847perhaps other cases.</p>
848<hr>
849<a name="111"><h3>111.&nbsp;istreambuf_iterator::equal overspecified, inefficient</h3></a><p><b>Section:</b>&nbsp;24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;15 Oct 1998</p>
850<p>The member istreambuf_iterator&lt;&gt;::equal is specified to be
851unnecessarily inefficient. While this does not affect the efficiency
852of conforming implementations of iostreams, because they can
853"reach into" the iterators and bypass this function, it does
854affect users who use istreambuf_iterators. </p>
855
856<p>The inefficiency results from a too-scrupulous definition, which
857requires a "true" result if neither iterator is at eof. In
858practice these iterators can only usefully be compared with the
859"eof" value, so the extra test implied provides no benefit,
860but slows down users' code. </p>
861
862<p>The solution is to weaken the requirement on the function to return
863true only if both iterators are at eof. </p>
864<p><b>Proposed resolution:</b></p>
865<p>Replace 24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a>,
866paragraph 1, </p>
867
868<blockquote>
869  <p>-1- Returns: true if and only if both iterators are at end-of-stream, or neither is at
870  end-of-stream, regardless of what streambuf object they use. </p>
871</blockquote>
872
873<p>with</p>
874
875<blockquote>
876  <p>-1- Returns: true if and only if both iterators are at
877  end-of-stream, regardless of what streambuf object they use. </p>
878</blockquote>
879
880<p><b>Rationale:</b></p>
881<p>It is not clear that this is a genuine defect.  Additionally, the
882LWG was reluctant to make a change that would result in
883operator== not being a equivalence relation.  One consequence of
884this change is that an algorithm that's passed the range [i, i)
885would no longer treat it as an empty range.</p>
886<hr>
887<a name="113"><h3>113.&nbsp;Missing/extra iostream sync semantics</h3></a><p><b>Section:</b>&nbsp;27.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream"> [lib.istream]</a>, 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;13 Oct 1998</p>
888<p>In 27.6.1.1, class basic_istream has a member function sync, described in 27.6.1.3,
889paragraph 36. </p>
890
891<p>Following the chain of definitions, I find that the various sync functions have defined
892semantics for output streams, but no semantics for input streams. On the other hand,
893basic_ostream has no sync function. </p>
894
895<p>The sync function should at minimum be added to basic_ostream, for internal
896consistency. </p>
897
898<p>A larger question is whether sync should have assigned semantics for input streams. </p>
899
900<p>Classic iostreams said streambuf::sync flushes pending output and attempts to return
901unread input characters to the source. It is a protected member function. The filebuf
902version (which is public) has that behavior (it backs up the read pointer). Class
903strstreambuf does not override streambuf::sync, and so sync can't be called on a
904strstream. </p>
905
906<p>If we can add corresponding semantics to the various sync functions, we should. If not,
907we should remove sync from basic_istream.</p>
908<p><b>Proposed resolution:</b></p>
909<p><b>Rationale:</b></p>
910<p>A sync function is not needed in basic_ostream because the flush function provides the
911desired functionality.</p>
912
913<p>As for the other points, the LWG finds the standard correct as written.</p>
914<hr>
915<a name="116"><h3>116.&nbsp;bitset cannot be constructed with a const char*</h3></a><p><b>Section:</b>&nbsp;23.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;6 Nov 1998</p>
916<p>The following code does not compile with the EDG compiler:</p>
917
918<blockquote>
919  <pre>#include &lt;bitset&gt;
920using namespace std;
921bitset&lt;32&gt; b("111111111");</pre>
922</blockquote>
923
924<p>If you cast the ctor argument to a string, i.e.:</p>
925
926<blockquote>
927  <pre>bitset&lt;32&gt; b(string("111111111"));</pre>
928</blockquote>
929
930<p>then it will compile. The reason is that bitset has the following templatized
931constructor:</p>
932
933<blockquote>
934  <pre>template &lt;class charT, class traits, class Allocator&gt;
935explicit bitset (const basic_string&lt;charT, traits, Allocator&gt;&amp; str, ...);</pre>
936</blockquote>
937
938<p>According to the compiler vendor, Steve Adamcyk at EDG, the user
939cannot pass this template constructor a <tt>const char*</tt> and
940expect a conversion to <tt>basic_string</tt>.  The reason is
941"When you have a template constructor, it can get used in
942contexts where type deduction can be done. Type deduction basically
943comes up with exact matches, not ones involving conversions."
944</p>
945
946<p>I don't think the intention when this constructor became
947templatized was for construction from a <tt>const char*</tt> to no
948longer work.</p>
949<p><b>Proposed resolution:</b></p>
950<p>Add to 23.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a> a bitset constructor declaration</p>
951
952<blockquote>
953  <pre>explicit bitset(const char*);</pre>
954</blockquote>
955
956<p>and in Section 23.3.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.cons"> [lib.bitset.cons]</a> add:</p>
957
958<blockquote>
959  <pre>explicit bitset(const char* str);</pre>
960  <p>Effects: <br>
961  &nbsp;&nbsp;&nbsp; Calls <tt>bitset((string) str, 0, string::npos);</tt></p>
962</blockquote>
963<p><b>Rationale:</b></p>
964<p>Although the problem is real, the standard is designed that way so
965it is not a defect.  Education is the immediate workaround. A future
966standard may wish to consider the Proposed Resolution as an
967extension.</p>
968<hr>
969<a name="121"><h3>121.&nbsp;Detailed definition for ctype&lt;wchar_t&gt; specialization</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
970<p>Section 22.1.1.1.1 has the following listed in Table 51: ctype&lt;char&gt; ,
971ctype&lt;wchar_t&gt;. </p>
972
973<p>Also Section 22.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype"> [lib.locale.ctype]</a> says: </p>
974
975<blockquote>
976  <p>The instantiations required in Table 51 (22.1.1.1.1) namely ctype&lt;char&gt; and
977  ctype&lt;wchar_t&gt; , implement character classing appropriate to the implementation's
978  native character set. </p>
979</blockquote>
980
981<p>However, Section 22.2.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.special"> [lib.facet.ctype.special]</a>
982only has a detailed description of the ctype&lt;char&gt; specialization, not the
983ctype&lt;wchar_t&gt; specialization. </p>
984<p><b>Proposed resolution:</b></p>
985<p>Add the ctype&lt;wchar_t&gt; detailed class description to Section
98622.2.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.special"> [lib.facet.ctype.special]</a>. </p>
987<p><b>Rationale:</b></p>
988<p>Specialization for wchar_t is not needed since the default is acceptable.</p>
989<hr>
990<a name="128"><h3>128.&nbsp;Need open_mode() function for file stream, string streams, file buffers, and string&nbsp; buffers</h3></a><p><b>Section:</b>&nbsp;27.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.string.streams"> [lib.string.streams]</a>, 27.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.file.streams"> [lib.file.streams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;22 Feb 1999</p>
991<p>The following question came from Thorsten Herlemann:</p>
992
993<blockquote>
994  <p>You can set a mode when constructing or opening a file-stream or
995  filebuf, e.g.  ios::in, ios::out, ios::binary, ... But how can I get
996  that mode later on, e.g. in my own operator &lt;&lt; or operator
997  &gt;&gt; or when I want to check whether a file-stream or
998  file-buffer object passed as parameter is opened for input or output
999  or binary? Is there no possibility? Is this a design-error in the
1000  standard C++ library? </p>
1001</blockquote>
1002
1003<p>It is indeed impossible to find out what a stream's or stream
1004buffer's open mode is, and without that knowledge you don't know
1005how certain operations behave. Just think of the append mode. </p>
1006
1007<p>Both streams and stream buffers should have a <tt>mode()</tt> function that returns the
1008current open mode setting. </p>
1009<p><b>Proposed resolution:</b></p>
1010<p>For stream buffers, add a function to the base class as a non-virtual function
1011qualified as const to 27.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a>:</p>
1012
1013<p>&nbsp;&nbsp;&nbsp;&nbsp;<tt>openmode mode() const</tt>;</p>
1014
1015<p><b>&nbsp;&nbsp;&nbsp; Returns</b> the current open mode.</p>
1016
1017<p>With streams, I'm not sure what to suggest. In principle, the mode
1018could already be returned by <tt>ios_base</tt>, but the mode is only
1019initialized for file and string stream objects, unless I'm overlooking
1020anything. For this reason it should be added to the most derived
1021stream classes. Alternatively, it could be added to <tt>basic_ios</tt>
1022and would be default initialized in <tt>basic_ios&lt;&gt;::init()</tt>.</p>
1023<p><b>Rationale:</b></p>
1024<p>This might be an interesting extension for some future, but it is
1025not a defect in the current standard. The Proposed Resolution is
1026retained for future reference.</p>
1027<hr>
1028<a name="131"><h3>131.&nbsp;list::splice throws nothing</h3></a><p><b>Section:</b>&nbsp;23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;6 Mar 1999</p>
1029<p>What happens if a splice operation causes the size() of a list to grow
1030beyond max_size()?</p>
1031<p><b>Proposed resolution:</b></p>
1032<p><b>Rationale:</b></p>
1033<p>Size() cannot grow beyond max_size().&nbsp; </p>
1034<hr>
1035<a name="135"><h3>135.&nbsp;basic_iostream doubly initialized</h3></a><p><b>Section:</b>&nbsp;27.6.1.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.cons"> [lib.iostream.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;6 Mar 1999</p>
1036<p>-1- Effects Constructs an object of class basic_iostream, assigning
1037initial values to the base classes by calling
1038basic_istream&lt;charT,traits&gt;(sb) (lib.istream) and
1039basic_ostream&lt;charT,traits&gt;(sb) (lib.ostream)</p>
1040
1041<p>The called for basic_istream and basic_ostream constructors call
1042init(sb). This means that the basic_iostream's virtual base class is
1043initialized twice.</p>
1044<p><b>Proposed resolution:</b></p>
1045<p>Change 27.6.1.5.1, paragraph 1 to:</p>
1046
1047<p>-1- Effects Constructs an object of class basic_iostream, assigning
1048initial values to the base classes by calling
1049basic_istream&lt;charT,traits&gt;(sb) (lib.istream).</p>
1050<p><b>Rationale:</b></p>
1051<p>The LWG agreed that the <tt> init()</tt> function is called
1052twice, but said that this is harmless and so not a defect in the
1053standard.</p>
1054<hr>
1055<a name="138"><h3>138.&nbsp;Class ctype_byname&lt;char&gt; redundant and misleading</h3></a><p><b>Section:</b>&nbsp;22.2.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;March 18, 1999</p>
1056<p>Section 22.2.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a> specifies that
1057ctype_byname&lt;char&gt; must be a specialization of the ctype_byname
1058template.</p>
1059
1060<p>It is common practice in the standard that specializations of class templates are only
1061mentioned where the interface of the specialization deviates from the interface of the
1062template that it is a specialization of. Otherwise, the fact whether or not a required
1063instantiation is an actual instantiation or a specialization is left open as an
1064implementation detail. </p>
1065
1066<p>Clause 22.2.1.4 deviates from that practice and for that reason is misleading. The
1067fact, that ctype_byname&lt;char&gt; is specified as a specialization suggests that there
1068must be something "special" about it, but it has the exact same interface as the
1069ctype_byname template. Clause 22.2.1.4 does not have any explanatory value, is at best
1070redundant, at worst misleading - unless I am missing anything. </p>
1071
1072<p>Naturally, an implementation will most likely implement ctype_byname&lt;char&gt; as a
1073specialization, because the base class ctype&lt;char&gt; is a specialization with an
1074interface different from the ctype template, but that's an implementation detail and need
1075not be mentioned in the standard. </p>
1076<p><b>Proposed resolution:</b></p>
1077<p><b>Rationale:</b></p>
1078<p> The standard as written is mildly misleading, but the correct fix
1079is to deal with the underlying problem in the ctype_byname base class,
1080not in the specialization. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a>.</p>
1081<hr>
1082<a name="140"><h3>140.&nbsp;map&lt;Key, T&gt;::value_type does not satisfy the assignable requirement</h3></a><p><b>Section:</b>&nbsp;23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Mark Mitchell&nbsp; <b>Date:</b>&nbsp;14 Apr 1999</p>
1083<blockquote>
1084  <p>23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a><br>
1085  <br>
1086  expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return type
1087  &nbsp;&nbsp;&nbsp;&nbsp; pre/post-condition<br>
1088  -------------&nbsp;&nbsp;&nbsp;&nbsp; ----------- &nbsp;&nbsp;&nbsp;&nbsp;
1089  -------------------<br>
1090  X::value_type&nbsp;&nbsp;&nbsp; T
1091  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
1092  T is assignable<br>
1093  <br>
1094  23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a><br>
1095  <br>
1096  A map satisfies all the requirements of a container.<br>
1097  <br>
1098  For a map&lt;Key, T&gt; ... the value_type is pair&lt;const Key, T&gt;.</p>
1099</blockquote>
1100
1101<p>There's a contradiction here. In particular, `pair&lt;const Key,
1102T&gt;' is not assignable; the `const Key' cannot be assigned
1103to. So,&nbsp; map&lt;Key, T&gt;::value_type does not satisfy the
1104assignable requirement imposed by a container.</p>
1105
1106<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
1107modification of set keys.]</i></p>
1108<p><b>Proposed resolution:</b></p>
1109<p><b>Rationale:</b></p>
1110<p>The LWG believes that the standard is inconsistent, but that this
1111is a design problem rather than a strict defect. May wish to
1112reconsider for the next standard.</p>
1113<hr>
1114<a name="143"><h3>143.&nbsp;C .h header wording unclear</h3></a><p><b>Section:</b>&nbsp;D.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.c.headers"> [depr.c.headers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Christophe de Dinechin&nbsp; <b>Date:</b>&nbsp;4 May 1999</p>
1115<p>[depr.c.headers] paragraph 2 reads:</p>
1116
1117<blockquote>
1118
1119<p>Each C header, whose name has the form name.h, behaves as if each
1120name placed in the Standard library namespace by the corresponding
1121cname header is also placed within the namespace scope of the
1122namespace std and is followed by an explicit using-declaration
1123(_namespace.udecl_)</p>
1124
1125</blockquote>
1126
1127<p>I think it should mention the global name space somewhere...&nbsp;
1128Currently, it indicates that name placed in std is also placed in
1129std...</p>
1130
1131<p>I don't know what is the correct wording. For instance, if struct
1132tm is defined in time.h, ctime declares std::tm. However, the current
1133wording seems ambiguous regarding which of the following would occur
1134for use of both ctime and time.h:</p>
1135
1136<blockquote>
1137  <pre>// version 1:
1138namespace std {
1139        struct tm { ... };
1140}
1141using std::tm;
1142
1143// version 2:
1144struct tm { ... };
1145namespace std {
1146        using ::tm;
1147}
1148
1149// version 3:
1150struct tm { ... };
1151namespace std {
1152        struct tm { ... };
1153}</pre>
1154</blockquote>
1155
1156<p>I think version 1 is intended.</p>
1157
1158<p><i>[Kona: The LWG agreed that the wording is not clear. It also
1159agreed that version 1 is intended, version 2 is not equivalent to
1160version 1, and version 3 is clearly not intended. The example below
1161was constructed by Nathan Myers to illustrate why version 2 is not
1162equivalent to version 1.</i></p>
1163
1164<p><i>Although not equivalent, the LWG is unsure if (2) is enough of
1165a problem to be prohibited. Points discussed in favor of allowing
1166(2):</i></p>
1167
1168<blockquote>
1169  <ul>
1170    <li><i>It may be a convenience to implementors.</i></li>
1171    <li><i>The only cases that fail are structs, of which the C library
1172      contains only a few.</i></li>
1173  </ul>
1174</blockquote>
1175
1176<p><i>]</i></p>
1177
1178<p><b>Example:</b></p>
1179
1180<blockquote>
1181
1182<pre>#include &lt;time.h&gt;
1183#include &lt;utility&gt;
1184
1185int main() {
1186    std::tm * t;
1187    make_pair( t, t ); // okay with version 1 due to Koenig lookup
1188                       // fails with version 2; make_pair not found
1189    return 0;
1190}</pre>
1191
1192</blockquote>
1193<p><b>Proposed resolution:</b></p>
1194
1195<p>Replace D.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.c.headers"> [depr.c.headers]</a> paragraph 2 with:</p>
1196
1197<blockquote>
1198
1199<p> Each C header, whose name has the form name.h, behaves as if each
1200name placed in the Standard library namespace by the corresponding
1201cname header is also placed within the namespace scope of the
1202namespace std by name.h and is followed by an explicit
1203using-declaration (_namespace.udecl_) in global scope.</p>
1204
1205</blockquote>
1206
1207<p><b>Rationale:</b></p>
1208<p> The current wording in the standard is the result of a difficult
1209compromise that averted delay of the standard. Based on discussions
1210in Tokyo it is clear that there is no still no consensus on stricter
1211wording, so the issue has been closed. It is suggested that users not
1212write code that depends on Koenig lookup of C library functions.</p>
1213<hr>
1214<a name="145"><h3>145.&nbsp;adjustfield lacks default value</h3></a><p><b>Section:</b>&nbsp;27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;12 May 1999</p>
1215<p>There is no initial value for the adjustfield defined, although
1216many people believe that the default adjustment were right. This is a
1217common misunderstanding. The standard only defines that, if no
1218adjustment is specified, all the predefined inserters must add fill
1219characters before the actual value, which is "as if" the
1220right flag were set. The flag itself need not be set.</p>
1221
1222<p>When you implement a user-defined inserter you cannot rely on right
1223being the default setting for the adjustfield. Instead, you must be
1224prepared to find none of the flags set and must keep in mind that in
1225this case you should make your inserter behave "as if" the
1226right flag were set. This is surprising to many people and complicates
1227matters more than necessary.</p>
1228
1229<p>Unless there is a good reason why the adjustfield should not be
1230initialized I would suggest to give it the default value that
1231everybody expects anyway.</p>
1232
1233<p><b>Proposed resolution:</b></p>
1234<p><b>Rationale:</b></p>
1235<p>This is not a defect. It is deliberate that the default is no bits
1236set. Consider Arabic or Hebrew, for example. See 22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a> paragraph 19, Table 61 - Fill padding.</p>
1237<hr>
1238<a name="149"><h3>149.&nbsp;Insert should return iterator to first element inserted</h3></a><p><b>Section:</b>&nbsp;23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;28 Jun 1999</p>
1239<p>Suppose that c and c1 are sequential containers and i is an
1240iterator that refers to an element of c.  Then I can insert a copy of
1241c1's elements into c ahead of element i by executing </p>
1242
1243<blockquote>
1244
1245<pre>c.insert(i, c1.begin(), c1.end());</pre>
1246
1247</blockquote>
1248
1249<p>If c is a vector, it is fairly easy for me to find out where the
1250newly inserted elements are, even though i is now invalid: </p>
1251
1252<blockquote>
1253
1254<pre>size_t i_loc = i - c.begin();
1255c.insert(i, c1.begin(), c1.end());</pre>
1256
1257</blockquote>
1258
1259<p>and now the first inserted element is at c.begin()+i_loc and one
1260past the last is at c.begin()+i_loc+c1.size().<br>
1261<br>
1262But what if c is a list? I can still find the location of one past the
1263last inserted element, because i is still valid. To find the location
1264of the first inserted element, though, I must execute something like </p>
1265
1266<blockquote>
1267
1268<pre>for (size_t n = c1.size(); n; --n)
1269   --i;</pre>
1270
1271</blockquote>
1272
1273<p>because i is now no longer a random-access iterator.<br>
1274<br>
1275Alternatively, I might write something like </p>
1276
1277<blockquote>
1278
1279<pre>bool first = i == c.begin();
1280list&lt;T&gt;::iterator j = i;
1281if (!first) --j;
1282c.insert(i, c1.begin(), c1.end());
1283if (first)
1284   j = c.begin();
1285else
1286   ++j;</pre>
1287
1288</blockquote>
1289
1290<p>which, although wretched, requires less overhead.<br>
1291<br>
1292But I think the right solution is to change the definition of insert
1293so that instead of returning void, it returns an iterator that refers
1294to the first element inserted, if any, and otherwise is a copy of its
1295first argument.&nbsp; </p>
1296<p><b>Proposed resolution:</b></p>
1297<p><b>Rationale:</b></p>
1298<p>The LWG believes this was an intentional design decision and so is
1299not a defect. It may be worth revisiting for the next standard.</p>
1300<hr>
1301<a name="157"><h3>157.&nbsp;Meaningless error handling for <tt>pword()</tt> and <tt>iword()</tt>
1302</h3></a><p><b>Section:</b>&nbsp;27.4.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.storage"> [lib.ios.base.storage]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar K�hl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
1303<p>According to paragraphs 2 and 4 of 27.4.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.storage"> [lib.ios.base.storage]</a>, the
1304functions <tt>iword()</tt> and <tt>pword()</tt> "set the
1305<tt>badbit</tt> (which might throw an exception)" on
1306failure. ... but what does it mean for <tt>ios_base</tt> to set the
1307<tt>badbit</tt>? The state facilities of the IOStream library are
1308defined in <tt>basic_ios</tt>, a derived class! It would be possible
1309to attempt a down cast but then it would be necessary to know the
1310character type used...</p>
1311<p><b>Proposed resolution:</b></p>
1312<p><b>Rationale:</b></p>
1313<p>Duplicate. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#41">41</a>.</p>
1314<hr>
1315<a name="162"><h3>162.&nbsp;Really "formatted input functions"?</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar K�hl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
1316<p>It appears to be somewhat nonsensical to consider the functions
1317defined in the paragraphs 1 to 5 to be "Formatted input
1318function" but since these functions are defined in a section
1319labeled "Formatted input functions" it is unclear to me
1320whether these operators are considered formatted input functions which
1321have to conform to the "common requirements" from 27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a>: If this is the case, all manipulators, not just
1322<tt>ws</tt>, would skip whitespace unless <tt>noskipws</tt> is set
1323(... but setting <tt>noskipws</tt> using the manipulator syntax would
1324also skip whitespace :-)</p>
1325
1326<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
1327output</p>
1328<p><b>Proposed resolution:</b></p>
1329<p><b>Rationale:</b></p>
1330<p>Duplicate. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a>.</p>
1331<hr>
1332<a name="163"><h3>163.&nbsp;Return of <tt>gcount()</tt> after a call to <tt>gcount</tt>
1333</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar K�hl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
1334<p>It is not clear which functions are to be considered unformatted
1335input functions. As written, it seems that all functions in 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> are unformatted input functions. However, it does not
1336really make much sense to construct a sentry object for
1337<tt>gcount()</tt>, <tt>sync()</tt>, ... Also it is unclear what
1338happens to the <tt>gcount()</tt> if eg. <tt>gcount()</tt>,
1339<tt>putback()</tt>, <tt>unget()</tt>, or <tt>sync()</tt> is called:
1340These functions don't extract characters, some of them even
1341"unextract" a character. Should this still be reflected in
1342<tt>gcount()</tt>? Of course, it could be read as if after a call to
1343<tt>gcount()</tt> <tt>gcount()</tt> return <tt>0</tt> (the last
1344unformatted input function, <tt>gcount()</tt>, didn't extract any
1345character) and after a call to <tt>putback()</tt> <tt>gcount()</tt>
1346returns <tt>-1</tt> (the last unformatted input function
1347<tt>putback()</tt> did "extract" back into the
1348stream). Correspondingly for <tt>unget()</tt>. Is this what is
1349intended?  If so, this should be clarified. Otherwise, a corresponding
1350clarification should be used.</p>
1351<p><b>Proposed resolution:</b></p>
1352<p><b>Rationale:</b></p>
1353<p>Duplicate.&nbsp; See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a>.</p>
1354<hr>
1355<a name="166"><h3>166.&nbsp;Really "formatted output functions"?</h3></a><p><b>Section:</b>&nbsp;27.6.2.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters"> [lib.ostream.inserters]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar K�hl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
1356<p>From 27.6.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.formatted.reqmts"> [lib.ostream.formatted.reqmts]</a> it appears that all the functions
1357defined in 27.6.2.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters"> [lib.ostream.inserters]</a> have to construct a
1358<tt>sentry</tt> object. Is this really intended?</p>
1359
1360<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
1361for output instead of input.</p>
1362<p><b>Proposed resolution:</b></p>
1363<p><b>Rationale:</b></p>
1364<p>Duplicate. See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a>.</p>
1365<hr>
1366<a name="177"><h3>177.&nbsp;Complex operators cannot be explicitly instantiated</h3></a><p><b>Section:</b>&nbsp;26.3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.ops"> [lib.complex.ops]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;2 Jul 1999</p>
1367<p>A user who tries to explicitly instantiate a complex non-member operator will
1368get compilation errors. Below is a simplified example of the reason why. The
1369problem is that iterator_traits cannot be instantiated on a non-pointer type
1370like float, yet when the compiler is trying to decide which operator+ needs to
1371be instantiated it must instantiate the declaration to figure out the first
1372argument type of a reverse_iterator operator.</p>
1373<pre>namespace std {
1374template &lt;class Iterator&gt;
1375struct iterator_traits
1376{
1377    typedef typename Iterator::value_type value_type;
1378};
1379
1380template &lt;class T&gt; class reverse_iterator;
1381
1382// reverse_iterator operator+
1383template &lt;class T&gt;
1384reverse_iterator&lt;T&gt; operator+
1385(typename iterator_traits&lt;T&gt;::difference_type, const reverse_iterator&lt;T&gt;&amp;);
1386
1387template &lt;class T&gt; struct complex {};
1388
1389// complex operator +
1390template &lt;class T&gt;
1391complex&lt;T&gt; operator+ (const T&amp; lhs, const complex&lt;T&gt;&amp; rhs)
1392{ return complex&lt;T&gt;();}
1393}
1394
1395// request for explicit instantiation
1396template std::complex&lt;float&gt; std::operator+&lt;float&gt;(const float&amp;,
1397     const std::complex&lt;float&gt;&amp;);</pre>
1398<p>See also c++-stdlib reflector messages: lib-6814, 6815, 6816.</p>
1399<p><b>Proposed resolution:</b></p>
1400<p><b>Rationale:</b></p>
1401<p>Implementors can make minor changes and the example will
1402work. Users are not affected in any case.</p> <p>According to John
1403Spicer, It is possible to explicitly instantiate these operators using
1404different syntax: change "std::operator+&lt;float&gt;" to
1405"std::operator+".</p>
1406
1407<p>The proposed resolution of issue 120 is that users will not be able
1408to explicitly instantiate standard library templates. If that
1409resolution is accepted then library implementors will be the only ones
1410that will be affected by this problem, and they must use the indicated
1411syntax.</p>
1412<hr>
1413<a name="178"><h3>178.&nbsp;Should clog and cerr initially be tied to cout?</h3></a><p><b>Section:</b>&nbsp;27.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.narrow.stream.objects"> [lib.narrow.stream.objects]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;2 Jul 1999</p>
1414<p>
1415Section 27.3.1 says "After the object cerr is initialized,
1416cerr.flags() &amp; unitbuf is nonzero. Its state is otherwise the same as
1417required for ios_base::init (lib.basic.ios.cons).  It doesn't say
1418anything about the the state of clog.  So this means that calling
1419cerr.tie() and clog.tie() should return 0 (see Table 89 for
1420ios_base::init effects).
1421</p>
1422<p>
1423Neither of the popular standard library implementations
1424that I tried does this, they both tie cerr and clog
1425to &amp;cout. I would think that would be what users expect.
1426</p>
1427<p><b>Proposed resolution:</b></p>
1428<p><b>Rationale:</b></p>
1429<p>The standard is clear as written.</p>
1430<p>27.3.1/5 says that "After the object cerr is initialized, cerr.flags()
1431&amp; unitbuf is nonzero. Its state is otherwise the same as required for
1432ios_base::init (27.4.4.1)." Table 89 in 27.4.4.1, which gives the
1433postconditions of basic_ios::init(), says that tie() is 0. (Other issues correct
1434ios_base::init to basic_ios::init().)</p>
1435<hr>
1436<a name="180"><h3>180.&nbsp;Container member iterator arguments constness has unintended consequences</h3></a><p><b>Section:</b>&nbsp;23 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.containers"> [lib.containers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;1 Jul 1999</p>
1437<p>It is the constness of the container which should control whether
1438it can be modified through a member function such as erase(), not the
1439constness of the iterators. The iterators only serve to give
1440positioning information.</p>
1441
1442<p>Here's a simple and typical example problem which is currently very
1443difficult or impossible to solve without the change proposed
1444below.</p>
1445
1446<p>Wrap a standard container C in a class W which allows clients to
1447find and read (but not modify) a subrange of (C.begin(), C.end()]. The
1448only modification clients are allowed to make to elements in this
1449subrange is to erase them from C through the use of a member function
1450of W.</p>
1451<p><b>Proposed resolution:</b></p>
1452<p>Change all non-const iterator parameters of standard library
1453container member functions to accept const_iterator parameters.
1454Note that this change applies to all library clauses, including
1455strings.</p>
1456
1457<p>For example, in   21.3.5.5  change:<br>
1458<br>
1459&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <tt>iterator erase(iterator p);</tt><br>
1460<br>
1461to:<br>
1462&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <tt>iterator erase(const_iterator p);</tt>
1463</p>
1464<p><b>Rationale:</b></p>
1465<p>The issue was discussed at length. It was generally agreed that 1)
1466There is no major technical argument against the change (although
1467there is a minor argument that some obscure programs may break), and
14682) Such a change would not break const correctness. The concerns about
1469making the change were 1) it is user detectable (although only in
1470boundary cases), 2) it changes a large number of signatures, and 3) it
1471seems more of a design issue that an out-and-out defect.</p>
1472
1473<p>The LWG believes that this issue should be considered as part of a
1474general review of const issues for the next revision of the
1475standard. Also see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#200">200</a>.</p>
1476<hr>
1477<a name="188"><h3>188.&nbsp;valarray helpers missing augmented assignment operators</h3></a><p><b>Section:</b>&nbsp;26.5.2.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.valarray.cassign"> [lib.valarray.cassign]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Gabriel Dos Reis&nbsp; <b>Date:</b>&nbsp;15 Aug 1999</p>
1478<p>26.5.2.6 defines augmented assignment operators
1479valarray&lt;T&gt;::op=(const T&amp;), but fails to provide
1480corresponding versions for the helper classes. Thus making the
1481following illegal:</p>
1482<blockquote>
1483<pre>#include &lt;valarray&gt;
1484
1485int main()
1486{
1487std::valarray&lt;double&gt; v(3.14, 1999);
1488
1489v[99] *= 2.0; // Ok
1490
1491std::slice s(0, 50, 2);
1492
1493v[s] *= 2.0; // ERROR
1494}</pre>
1495</blockquote>
1496<p>I can't understand the intent of that omission.  It makes the
1497valarray library less intuitive and less useful.</p>
1498<p><b>Proposed resolution:</b></p>
1499<p><b>Rationale:</b></p>
1500<p>Although perhaps an unfortunate
1501design decision, the omission is not a defect in the current
1502standard.&nbsp; A future standard may wish to add the missing
1503operators.</p>
1504<hr>
1505<a name="190"><h3>190.&nbsp;min() and max() functions should be std::binary_functions</h3></a><p><b>Section:</b>&nbsp;25.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Mark Rintoul&nbsp; <b>Date:</b>&nbsp;26 Aug 1999</p>
1506<p>Both std::min and std::max are defined as template functions.  This
1507is very different than the definition of std::plus (and similar
1508structs) which are defined as function objects which inherit
1509std::binary_function.<br>
1510<br>
1511        This lack of inheritance leaves std::min and std::max somewhat useless in standard library algorithms which require
1512a function object that inherits std::binary_function.</p>
1513<p><b>Proposed resolution:</b></p>
1514<p><b>Rationale:</b></p>
1515<p>Although perhaps an unfortunate design decision, the omission is not a defect
1516in the current standard.&nbsp; A future standard may wish to consider additional
1517function objects.</p>
1518<hr>
1519<a name="191"><h3>191.&nbsp;Unclear complexity for algorithms such as binary search</h3></a><p><b>Section:</b>&nbsp;25.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.binary.search"> [lib.alg.binary.search]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;10 Oct 1999</p>
1520<p>The complexity of binary_search() is stated as "At most
1521log(last-first) + 2 comparisons", which seems to say that the
1522algorithm has logarithmic complexity. However, this algorithms is
1523defined for forward iterators. And for forward iterators, the need to
1524step element-by-element results into linear complexity. But such a
1525statement is missing in the standard. The same applies to
1526lower_bound(), upper_bound(), and equal_range().&nbsp;<br>
1527<br>
1528However, strictly speaking the standard contains no bug here. So this
1529might considered to be a clarification or improvement.
1530</p>
1531<p><b>Proposed resolution:</b></p>
1532<p><b>Rationale:</b></p>
1533<p>The complexity is expressed in terms of comparisons, and that
1534complexity can be met even if the number of iterators accessed is
1535linear. Paragraph 1 already says exactly what happens to
1536iterators.</p>
1537<hr>
1538<a name="192"><h3>192.&nbsp;a.insert(p,t) is inefficient and overconstrained</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Ed Brey&nbsp; <b>Date:</b>&nbsp;6 Jun 1999</p>
1539<p>As defined in 23.1.2, paragraph 7 (table 69), a.insert(p,t) suffers from
1540several problems:</p>
1541<table border="1" cellpadding="5">
1542  <tbody><tr>
1543    <td><b>expression</b></td>
1544    <td><b>return type</b></td>
1545    <td><b>pre/post-condition</b></td>
1546    <td><b>complexity</b></td>
1547  </tr>
1548  <tr>
1549    <td><tt>a.insert(p,t)</tt></td>
1550    <td><tt>iterator</tt></td>
1551    <td>inserts t if and only if there is no element with key equivalent to the key of
1552       t in containers with unique keys; always inserts t in containers with equivalent
1553       keys. always returns the iterator pointing to the element with key equivalent to
1554       the key of t . iterator p is a hint pointing to where the insert should start to search.</td>
1555    <td>logarithmic in general, but amortized constant if t is inserted right after p .</td>
1556  </tr>
1557</tbody></table>
1558<p>1. For a container with unique keys, only logarithmic complexity is
1559guaranteed if no element is inserted, even though constant complexity is always
1560possible if p points to an element equivalent to t.</p>
1561<p>2. For a container with equivalent keys, the amortized constant complexity
1562guarantee is only useful if no key equivalent to t exists in the container.
1563Otherwise, the insertion could occur in one of multiple locations, at least one
1564of which would not be right after p.</p>
1565<p>3. By guaranteeing amortized constant complexity only when t is inserted
1566after p, it is impossible to guarantee constant complexity if t is inserted at
1567the beginning of the container. Such a problem would not exist if amortized
1568constant complexity was guaranteed if t is inserted before p, since there is
1569always some p immediately before which an insert can take place.</p>
1570<p>4. For a container with equivalent keys, p does not allow specification of
1571where to insert the element, but rather only acts as a hint for improving
1572performance. This negates the added functionality that p would provide if it
1573specified where within a sequence of equivalent keys the insertion should occur.
1574Specifying the insert location provides more control to the user, while
1575providing no disadvantage to the container implementation.</p>
1576<p><b>Proposed resolution:</b></p>
1577<p>In 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> paragraph 7, replace the row in table 69
1578for a.insert(p,t) with the following two rows:</p>
1579<table border="1" cellpadding="5">
1580  <tbody><tr>
1581    <td><b>expression</b></td>
1582    <td><b>return type</b></td>
1583    <td><b>pre/post-condition</b></td>
1584    <td><b>complexity</b></td>
1585  </tr>
1586  <tr>
1587    <td><tt>a_uniq.insert(p,t)</tt></td>
1588    <td><tt>iterator</tt></td>
1589    <td>inserts t if and only if there is no element with key equivalent to the
1590      key of t. returns the iterator pointing to the element with key equivalent
1591      to the key of t.</td>
1592    <td>logarithmic in general, but amortized constant if t is inserted right
1593      before p or p points to an element with key equivalent to t.</td>
1594  </tr>
1595  <tr>
1596    <td><tt>a_eq.insert(p,t)</tt></td>
1597    <td><tt>iterator</tt></td>
1598    <td>inserts t and returns the iterator pointing to the newly inserted
1599      element. t is inserted right before p if doing so preserves the container
1600      ordering.</td>
1601    <td>logarithmic in general, but amortized constant if t is inserted right
1602      before p.</td>
1603  </tr>
1604</tbody></table>
1605
1606<p><b>Rationale:</b></p>
1607<p>Too big a change.&nbsp; Furthermore, implementors report checking
1608both before p and after p, and don't want to change this behavior.</p>
1609<hr>
1610<a name="194"><h3>194.&nbsp;rdbuf() functions poorly specified</h3></a><p><b>Section:</b>&nbsp;27.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios"> [lib.ios]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;7 Sep 1999</p>
1611<p>In classic iostreams, base class ios had an rdbuf function that returned a
1612pointer to the associated streambuf. Each derived class had its own rdbuf
1613function that returned a pointer of a type reflecting the actual type derived
1614from streambuf. Because in ARM C++, virtual function overrides had to have the
1615same return type, rdbuf could not be virtual.</p>
1616<p>In standard iostreams, we retain the non-virtual rdbuf function design, and
1617in addition have an overloaded rdbuf function that sets the buffer pointer.
1618There is no need for the second function to be virtual nor to be implemented in
1619derived classes.</p>
1620<p>Minor question: Was there a specific reason not to make the original rdbuf
1621function virtual?</p>
1622<p>Major problem: Friendly compilers warn about functions in derived classes
1623that hide base-class overloads. Any standard implementation of iostreams will
1624result in such a warning on each of the iostream classes, because of the
1625ill-considered decision to overload rdbuf only in a base class.</p>
1626<p>In addition, users of the second rdbuf function must use explicit
1627qualification or a cast to call it from derived classes. An explicit
1628qualification or cast to basic_ios would prevent access to any later overriding
1629version if there was one.</p>
1630<p>What I'd like to do in an implementation is add a using- declaration for the
1631second rdbuf function in each derived class. It would eliminate warnings about
1632hiding functions, and would enable access without using explicit qualification.
1633Such a change I don't think would change the behavior of any valid program, but
1634would allow invalid programs to compile:</p>
1635<blockquote>
1636  <pre> filebuf mybuf;
1637 fstream f;
1638 f.rdbuf(mybuf); // should be an error, no visible rdbuf</pre>
1639</blockquote>
1640<p>I'd like to suggest this problem as a defect, with the proposed resolution to
1641require the equivalent of a using-declaration for the rdbuf function that is not
1642replaced in a later derived class. We could discuss whether replacing the
1643function should be allowed.</p>
1644<p><b>Proposed resolution:</b></p>
1645<p><b>Rationale:</b></p>
1646<p>For historical reasons, the standard is correct as written. There is a subtle difference between the base
1647class <tt> rdbuf()</tt> and derived class <tt>rdbuf()</tt>. The derived
1648class <tt> rdbuf()</tt> always returns the original streambuf, whereas the base class
1649<tt> rdbuf()</tt> will return the "current streambuf" if that has been changed by the variant you mention.</p>
1650
1651<p>Permission is not required to add such an extension.  See
165217.4.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.member.functions"> [lib.member.functions]</a>.</p>
1653<hr>
1654<a name="196"><h3>196.&nbsp;Placement new example has alignment problems</h3></a><p><b>Section:</b>&nbsp;18.5.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.placement"> [lib.new.delete.placement]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Herb Sutter&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
1655<p>The example in 18.5.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.placement"> [lib.new.delete.placement]</a> paragraph 4 reads: </p>
1656
1657<blockquote>
1658
1659<p>[Example: This can be useful for constructing an object at a known address:<br>
1660<br>
1661<tt>&nbsp;&nbsp; char place[sizeof(Something)];<br>
1662&nbsp;&nbsp; Something* p = new (place) Something();<br>
1663<br>
1664</tt>end example] </p>
1665
1666</blockquote>
1667
1668<p>This example has potential alignment problems. </p>
1669<p><b>Proposed resolution:</b></p>
1670<p><b>Rationale:</b></p>
1671<p>Duplicate: see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a>.</p>
1672<hr>
1673<a name="197"><h3>197.&nbsp;max_size() underspecified</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>, 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;21 Oct 1999</p>
1674<p>Must the value returned by max_size() be unchanged from call to call? </p>
1675
1676<p>Must the value returned from max_size() be meaningful? </p>
1677
1678<p>Possible meanings identified in lib-6827: </p>
1679
1680<p>1) The largest container the implementation can support given "best
1681case" conditions - i.e. assume the run-time platform is "configured to
1682the max", and no overhead from the program itself. This may possibly
1683be determined at the point the library is written, but certainly no
1684later than compile time.<br>
1685<br>
16862) The largest container the program could create, given "best case"
1687conditions - i.e. same platform assumptions as (1), but take into
1688account any overhead for executing the program itself. (or, roughly
1689"storage=storage-sizeof(program)"). This does NOT include any resource
1690allocated by the program. This may (or may not) be determinable at
1691compile time.<br>
1692<br>
16933) The largest container the current execution of the program could
1694create, given knowledge of the actual run-time platform, but again,
1695not taking into account any currently allocated resource. This is
1696probably best determined at program start-up.<br>
1697<br>
16984) The largest container the current execution program could create at
1699the point max_size() is called (or more correctly at the point
1700max_size() returns :-), given it's current environment (i.e. taking
1701into account the actual currently available resources). This,
1702obviously, has to be determined dynamically each time max_size() is
1703called. </p>
1704<p><b>Proposed resolution:</b></p>
1705<p><b>Rationale:</b></p>
1706<p>max_size() isn't useful for very many things, and the existing
1707  wording is sufficiently clear for the few cases that max_size() can
1708  be used for.  None of the attempts to change the existing wording
1709  were an improvement.</p>
1710
1711<p>It is clear to the LWG that the value returned by max_size() can't
1712  change from call to call.</p>
1713
1714<hr>
1715<a name="203"><h3>203.&nbsp;basic_istream::sentry::sentry() is uninstantiable with ctype&lt;user-defined type&gt;</h3></a><p><b>Section:</b>&nbsp;27.6.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt McClure and Dietmar K�hl&nbsp; <b>Date:</b>&nbsp;1 Jan 2000</p>
1716<p>27.6.1.1.2 Paragraph 4 states:</p>
1717<blockquote>
1718  <p>To decide if the character c is a whitespace character, the constructor
1719     performs ''as if'' it executes the following code fragment:&nbsp;</p>
1720  <pre>const ctype&lt;charT&gt;&amp; ctype = use_facet&lt;ctype&lt;charT&gt; &gt;(is.getloc());
1721if (ctype.is(ctype.space,c)!=0)
1722// c is a whitespace character.</pre>
1723</blockquote>
1724
1725<p> But Table 51 in 22.1.1.1.1 only requires an implementation to
1726provide specializations for ctype&lt;char&gt; and
1727ctype&lt;wchar_t&gt;.  If sentry's constructor is implemented using
1728ctype, it will be uninstantiable for a user-defined character type
1729charT, unless the implementation has provided non-working (since it
1730would be impossible to define a correct ctype&lt;charT&gt; specialization
1731for an arbitrary charT) definitions of ctype's virtual member
1732functions.</p>
1733
1734<p>
1735It seems the intent the standard is that sentry should behave, in
1736every respect, not just during execution, as if it were implemented
1737using ctype, with the burden of providing a ctype specialization
1738falling on the user.  But as it is written, nothing requires the
1739translation of sentry's constructor to behave as if it used the above
1740code, and it would seem therefore, that sentry's constructor should be
1741instantiable for all character types.
1742</p>
1743
1744<p>
1745Note: If I have misinterpreted the intent of the standard with
1746respect to sentry's constructor's instantiability, then a note should
1747be added to the following effect:
1748</p>
1749
1750<blockquote>
1751An implementation is forbidden from using the above code if it renders
1752the constructor uninstantiable for an otherwise valid character
1753type.
1754</blockquote>
1755
1756<p>In any event, some clarification is needed.</p>
1757
1758<p><b>Proposed resolution:</b></p>
1759<p><b>Rationale:</b></p>
1760<p>It is possible but not easy to instantiate on types other than char
1761or wchar_t; many things have to be done first. That is by intention
1762and is not a defect.</p>
1763<hr>
1764<a name="204"><h3>204.&nbsp;distance(first, last) when "last" is before "first"</h3></a><p><b>Section:</b>&nbsp;24.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.operations"> [lib.iterator.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Rintala Matti&nbsp; <b>Date:</b>&nbsp;28 Jan 2000</p>
1765<p>Section 24.3.4 describes the function distance(first, last) (where first and
1766last are iterators) which calculates "the number of increments or
1767decrements needed to get from 'first' to 'last'".</p>
1768<p>The function should work for forward, bidirectional and random access
1769iterators, and there is a requirement 24.3.4.5 which states that "'last'
1770must be reachable from 'first'".</p>
1771<p>With random access iterators the function is easy to implement as "last
1772- first".</p>
1773<p>With forward iterators it's clear that 'first' must point to a place before
1774'last', because otherwise 'last' would not be reachable from 'first'.</p>
1775<p>But what about bidirectional iterators? There 'last' is reachable from
1776'first' with the -- operator even if 'last' points to an earlier position than
1777'first'. However, I cannot see how the distance() function could be implemented
1778if the implementation does not know which of the iterators points to an earlier
1779position (you cannot use ++ or -- on either iterator if you don't know which
1780direction is the "safe way to travel").</p>
1781<p>The paragraph 24.3.4.1 states that "for ... bidirectional iterators they
1782use ++ to provide linear time implementations". However, the ++ operator is
1783not mentioned in the reachability requirement. Furthermore 24.3.4.4 explicitly
1784mentions that distance() returns the number of increments _or decrements_,
1785suggesting that it could return a negative number also for bidirectional
1786iterators when 'last' points to a position before 'first'.</p>
1787<p>Is a further requirement is needed to state that for forward and
1788bidirectional iterators "'last' must be reachable from 'first' using the ++
1789operator". Maybe this requirement might also apply to random access
1790iterators so that distance() would work the same way for every iterator
1791category?</p>
1792<p><b>Proposed resolution:</b></p>
1793<p><b>Rationale:</b></p>
1794<p>"Reachable" is defined in the standard in 24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a> paragraph 6.
1795The definition is only in terms of operator++(). The LWG sees no defect in
1796the standard.</p>
1797<hr>
1798<a name="205"><h3>205.&nbsp; numeric_limits unclear on how to determine floating point types</h3></a><p><b>Section:</b>&nbsp;18.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.limits.members"> [lib.numeric.limits.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Cleary&nbsp; <b>Date:</b>&nbsp;28 Jan 2000</p>
1799<p>In several places in 18.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.limits.members"> [lib.numeric.limits.members]</a>, a member is
1800described as "Meaningful for all floating point types."
1801However, no clear method of determining a floating point type is
1802provided.</p>
1803
1804<p>In 18.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.special"> [lib.numeric.special]</a>, paragraph 1 states ". . . (for
1805example, epsilon() is only meaningful if is_integer is
1806false). . ." which suggests that a type is a floating point type
1807if is_specialized is true and is_integer is false; however, this is
1808unclear.</p>
1809
1810<p>When clarifying this, please keep in mind this need of users: what
1811exactly is the definition of floating point? Would a fixed point or
1812rational representation be considered one? I guess my statement here
1813is that there could also be types that are neither integer or
1814(strictly) floating point.</p>
1815<p><b>Proposed resolution:</b></p>
1816<p><b>Rationale:</b></p>
1817<p>It is up to the implementor of a user define type to decide if it is a
1818floating point type.</p>
1819<hr>
1820<a name="207"><h3>207.&nbsp;ctype&lt;char&gt; members return clause incomplete</h3></a><p><b>Section:</b>&nbsp;22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Robert Klarer&nbsp; <b>Date:</b>&nbsp;2 Nov 1999</p>
1821<p>
1822The <tt>widen</tt> and <tt>narrow</tt> member functions are described
1823in 22.2.1.3.2, paragraphs 9-11.  In each case we have two overloaded
1824signatures followed by a <b>Returns</b> clause.  The <b>Returns</b>
1825clause only describes one of the overloads.
1826</p>
1827<p><b>Proposed resolution:</b></p>
1828<p>Change the returns clause in 22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>
1829paragraph 10 from:</p>
1830<p>&nbsp;&nbsp;&nbsp; Returns: do_widen(low, high, to).</p>
1831
1832<p>to:</p>
1833<p>&nbsp;&nbsp;&nbsp; Returns: do_widen(c) or do_widen(low, high, to),
1834respectively.</p>
1835
1836<p>Change the returns clause in 22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a> paragraph 11
1837from:</p>
1838<p>&nbsp;&nbsp;&nbsp; Returns: do_narrow(low, high, to).</p>
1839
1840<p>to:</p>
1841<p>&nbsp;&nbsp;&nbsp; Returns: do_narrow(c) or do_narrow(low, high, to),
1842respectively.</p>
1843<p><b>Rationale:</b></p>
1844<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
1845paragraphs.</p>
1846<hr>
1847<a name="213"><h3>213.&nbsp;Math function overloads ambiguous</h3></a><p><b>Section:</b>&nbsp;26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;26 Feb 2000</p>
1848<p>Due to the additional overloaded versions of numeric functions for
1849float and long double according to Section 26.5, calls such as int x;
1850std::pow (x, 4) are ambiguous now in a standard conforming
1851implementation. Current implementations solve this problem very
1852different (overload for all types, don't overload for float and long
1853double, use preprocessor, follow the standard and get
1854ambiguities).</p> <p>This behavior should be standardized or at least
1855identified as implementation defined.</p>
1856<p><b>Proposed resolution:</b></p>
1857<p><b>Rationale:</b></p>
1858<p>These math issues are an
1859understood and accepted consequence of the design. They have
1860been discussed several times in the past. Users must write casts
1861or write floating point expressions as arguments.</p>
1862<hr>
1863<a name="215"><h3>215.&nbsp;Can a map's key_type be const?</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;29 Feb 2000</p>
1864<p>A user noticed that this doesn't compile with the Rogue Wave library because
1865the rb_tree class declares a key_allocator, and allocator&lt;const int&gt; is
1866not legal, I think:</p>
1867<blockquote>
1868  <pre>map &lt; const int, ... &gt; // legal?</pre>
1869</blockquote>
1870<p>which made me wonder whether it is legal for a map's key_type to be const. In
1871email from Matt Austern he said:</p>
1872<blockquote>
1873<p>I'm not sure whether it's legal to declare a map with a const key type. I
1874hadn't thought about that question until a couple weeks ago. My intuitive
1875feeling is that it ought not to be allowed, and that the standard ought to say
1876so. It does turn out to work in SGI's library, though, and someone in the
1877compiler group even used it. Perhaps this deserves to be written up as an issue
1878too.</p>
1879</blockquote>
1880<p><b>Proposed resolution:</b></p>
1881<p><b>Rationale:</b></p>
1882<p>The "key is assignable" requirement from table 69 in
188323.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> already implies the key cannot be const.</p>
1884<hr>
1885<a name="216"><h3>216.&nbsp;setbase manipulator description flawed</h3></a><p><b>Section:</b>&nbsp;27.6.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Hyman Rosen&nbsp; <b>Date:</b>&nbsp;29 Feb 2000</p>
1886<p>27.6.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a> paragraph 5 says:</p>
1887<blockquote>
1888<pre>smanip setbase(int base);</pre>
1889<p> Returns: An object s of unspecified type such that if out is an
1890(instance of) basic_ostream then the expression out&lt;&lt;s behaves
1891as if f(s) were called, in is an (instance of) basic_istream then the
1892expression in&gt;&gt;s behaves as if f(s) were called. Where f can be
1893defined as:</p>
1894<pre>ios_base&amp; f(ios_base&amp; str, int base)
1895{
1896  // set basefield
1897  str.setf(n == 8 ? ios_base::oct :
1898                n == 10 ? ios_base::dec :
1899                n == 16 ? ios_base::hex :
1900                  ios_base::fmtflags(0), ios_base::basefield);
1901  return str;
1902}</pre>
1903</blockquote>
1904<p>There are two problems here. First, f takes two parameters, so the
1905description needs to say that out&lt;&lt;s and in&gt;&gt;s behave as if f(s,base)
1906had been called. Second, f is has a parameter named base, but is written as if
1907the parameter was named n.</p>
1908<p>Actually, there's a third problem. The paragraph has grammatical errors.
1909There needs to be an "and" after the first comma, and the "Where
1910f" sentence fragment needs to be merged into its preceding sentence. You
1911may also want to format the function a little better. The formatting above is
1912more-or-less what the Standard contains.</p>
1913<p><b>Proposed resolution:</b></p>
1914<p><b>Rationale:</b></p>
1915<p>The resolution of this defect is subsumed by the proposed resolution for
1916issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#193">193</a>.</p>
1917
1918<p><i>[Tokyo: The LWG agrees that this is a defect and notes that it
1919occurs additional places in the section, all requiring fixes.]</i></p>
1920<hr>
1921<a name="218"><h3>218.&nbsp;Algorithms do not use binary predicate objects for default comparisons</h3></a><p><b>Section:</b>&nbsp;25.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.sorting"> [lib.alg.sorting]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Pablo Halpern&nbsp; <b>Date:</b>&nbsp;6 Mar 2000</p>
1922<p>Many of the algorithms take an argument, pred, of template parameter type
1923BinaryPredicate or an argument comp of template parameter type Compare. These
1924algorithms usually have an overloaded version that does not take the predicate
1925argument. In these cases pred is usually replaced by the use of operator== and
1926comp is replaced by the use of operator&lt;.</p>
1927<p>This use of hard-coded operators is inconsistent with other parts of the
1928library, particularly the containers library, where equality is established
1929using equal_to&lt;&gt; and ordering is established using less&lt;&gt;. Worse,
1930the use of operator&lt;, would cause the following innocent-looking code to have
1931undefined behavior:</p>
1932<blockquote>
1933  <pre>vector&lt;string*&gt; vec;
1934sort(vec.begin(), vec.end());</pre>
1935</blockquote>
1936<p>The use of operator&lt; is not defined for pointers to unrelated objects. If
1937std::sort used less&lt;&gt; to compare elements, then the above code would be
1938well-defined, since less&lt;&gt; is explicitly specialized to produce a total
1939ordering of pointers.</p>
1940<p><b>Proposed resolution:</b></p>
1941<p><b>Rationale:</b></p>
1942<p>This use of operator== and operator&lt; was a very deliberate, conscious, and
1943explicitly made design decision; these operators are often more efficient. The
1944predicate forms are available for users who don't want to rely on operator== and
1945operator&lt;.</p>
1946<hr>
1947<a name="219"><h3>219.&nbsp;find algorithm missing version that takes a binary predicate argument</h3></a><p><b>Section:</b>&nbsp;25.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.find"> [lib.alg.find]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Pablo Halpern&nbsp; <b>Date:</b>&nbsp;6 Mar 2000</p>
1948<p>The find function always searches for a value using operator== to compare the
1949value argument to each element in the input iterator range. This is inconsistent
1950with other find-related functions such as find_end and find_first_of, which
1951allow the caller to specify a binary predicate object to be used for determining
1952equality. The fact that this can be accomplished using a combination of find_if
1953and bind_1st or bind_2nd does not negate the desirability of a consistent,
1954simple, alternative interface to find.</p>
1955<p><b>Proposed resolution:</b></p>
1956<blockquote>
1957<p>In section 25.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.find"> [lib.alg.find]</a>, add a second prototype for find
1958(between the existing prototype and the prototype for find_if), as
1959follows:</p>
1960<pre>    template&lt;class InputIterator, class T, class BinaryPredicate&gt;
1961      InputIterator find(InputIterator first, InputIterator last,
1962                         const T&amp; value, BinaryPredicate bin_pred);</pre>
1963<p>Change the description of the return from:</p>
1964<blockquote>
1965  <p>Returns: The first iterator i in the range [first, last) for which the following corresponding
1966  conditions hold: *i == value, pred(*i) != false. Returns last if no such iterator is found.</p>
1967</blockquote>
1968<p>&nbsp;to:</p>
1969<blockquote>
1970  <p>Returns: The first iterator i in the range [first, last) for which the following&nbsp;
1971  corresponding condition holds: *i == value, bin_pred(*i,value) != false, pred(*)
1972  != false. Return last if no such iterator is found.</p>
1973</blockquote>
1974</blockquote>
1975<p><b>Rationale:</b></p>
1976<p>This is request for a pure extension, so it is not a defect in the
1977current standard.&nbsp; As the submitter pointed out, "this can
1978be accomplished using a combination of find_if and bind_1st or
1979bind_2nd".</p>
1980<hr>
1981<a name="236"><h3>236.&nbsp;ctype&lt;char&gt;::is() member modifies facet</h3></a><p><b>Section:</b>&nbsp;22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar K�hl&nbsp; <b>Date:</b>&nbsp;24 Apr 2000</p>
1982<p>The description of the <tt>is()</tt> member in paragraph 4 of 22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a> is broken: According to this description, the
1983second form of the <tt>is()</tt> method modifies the masks in the
1984<tt>ctype</tt> object. The correct semantics if, of course, to obtain
1985an array of masks. The corresponding method in the general case,
1986ie. the <tt>do_is()</tt> method as described in 22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a> paragraph 1 does the right thing.</p>
1987<p><b>Proposed resolution:</b></p>
1988  <p>Change paragraph 4 from</p>
1989    <blockquote>
1990    The second form, for all *p in the range [low, high), assigns
1991    vec[p-low] to table()[(unsigned char)*p].
1992    </blockquote>
1993  <p>to become</p>
1994    <blockquote>
1995    The second form, for all *p in the range [low, high), assigns
1996    table()[(unsigned char)*p] to vec[p-low].
1997  </blockquote>
1998<p><b>Rationale:</b></p>
1999<p>Duplicate.  See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#28">28</a>.</p>
2000<hr>
2001<a name="244"><h3>244.&nbsp;Must <tt>find</tt>'s third argument be CopyConstructible?</h3></a><p><b>Section:</b>&nbsp;25.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.find"> [lib.alg.find]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;02 May 2000</p>
2002<p>Is the following implementation of <tt>find</tt> acceptable?</p>
2003
2004<pre>        template&lt;class Iter, class X&gt;
2005        Iter find(Iter begin, Iter end, const X&amp; x)
2006        {
2007            X x1 = x;           // this is the crucial statement
2008            while (begin != end &amp;&amp; *begin != x1)
2009                ++begin;
2010            return begin;
2011        }
2012</pre>
2013
2014<p>If the answer is yes, then it is implementation-dependent as to
2015whether the following fragment is well formed:</p>
2016
2017<pre>        vector&lt;string&gt; v;
2018
2019        find(v.begin(), v.end(), "foo");
2020</pre>
2021
2022<p>At issue is whether there is a requirement that the third argument
2023of find be CopyConstructible.  There may be no problem here, but
2024analysis is necessary.</p>
2025<p><b>Proposed resolution:</b></p>
2026<p><b>Rationale:</b></p>
2027<p>There is no indication in the standard that find's third argument
2028is required to be Copy Constructible.  The LWG believes that no such
2029requirement was intended.  As noted above, there are times when a user
2030might reasonably pass an argument that is not Copy Constructible.</p>
2031<hr>
2032<a name="245"><h3>245.&nbsp;Which operations on <tt>istream_iterator</tt> trigger input operations?</h3></a><p><b>Section:</b>&nbsp;24.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istream.iterator"> [lib.istream.iterator]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;02 May 2000</p>
2033<p>I do not think the standard specifies what operation(s) on istream
2034iterators trigger input operations.  So, for example:</p>
2035
2036<pre>        istream_iterator&lt;int&gt; i(cin);
2037
2038        int n = *i++;
2039</pre>
2040
2041<p>I do not think it is specified how many integers have been read
2042from cin.  The number must be at least 1, of course, but can it be 2?
2043More?</p>
2044<p><b>Proposed resolution:</b></p>
2045<p><b>Rationale:</b></p>
2046<p>The standard is clear as written: the stream is read every time
2047operator++ is called, and it is also read either when the iterator is
2048constructed or when operator* is called for the first time.  In the
2049example above, exactly two integers are read from cin.</p>
2050
2051<p>There may be a problem with the interaction between istream_iterator
2052and some STL algorithms, such as find.  There are no guarantees about
2053how many times find may invoke operator++.</p>
2054<hr>
2055<a name="246"><h3>246.&nbsp;<tt>a.insert(p,t)</tt> is incorrectly specified</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Mark Rodgers&nbsp; <b>Date:</b>&nbsp;19 May 2000</p>
2056<p>Closed issue 192 raised several problems with the specification of
2057this function, but was rejected as Not A Defect because it was too big
2058a change with unacceptable impacts on existing implementations.
2059However, issues remain that could be addressed with a smaller change
2060and with little or no consequent impact.</p>
2061
2062<ol>
2063   <li>
2064<p> The specification is inconsistent with the original
2065   proposal and with several implementations.</p>
2066
2067   <p>The initial implementation by Hewlett Packard only ever looked
2068   immediately <i>before</i> p, and I do not believe there was any
2069   intention to standardize anything other than this behavior.
2070   Consequently, current implementations by several leading
2071   implementors also look immediately before p, and will only insert
2072   after p in logarithmic time.  I am only aware of one implementation
2073   that does actually look after p, and it looks before p as well.  It
2074   is therefore doubtful that existing code would be relying on the
2075   behavior defined in the standard, and it would seem that fixing
2076   this defect as proposed below would standardize existing
2077   practice.</p>
2078</li>
2079
2080   <li>
2081<p>
2082   The specification is inconsistent with insertion for sequence
2083   containers.</p>
2084
2085   <p>This is difficult and confusing to teach to newcomers.  All
2086   insert operations that specify an iterator as an insertion location
2087   should have a consistent meaning for the location represented by
2088   that iterator.</p>
2089</li>
2090
2091   <li>
2092<p> As specified, there is no way to hint that the insertion
2093   should occur at the beginning of the container, and the way to hint
2094   that it should occur at the end is long winded and unnatural.</p>
2095
2096   <p>For a container containing n elements, there are n+1 possible
2097   insertion locations and n+1 valid iterators.  For there to be a
2098   one-to-one mapping between iterators and insertion locations, the
2099   iterator must represent an insertion location immediately before
2100   the iterator.</p>
2101</li>
2102
2103   <li>
2104<p> When appending sorted ranges using insert_iterators,
2105   insertions are guaranteed to be sub-optimal.</p>
2106
2107   <p>In such a situation, the optimum location for insertion is
2108   always immediately after the element previously inserted.  The
2109   mechanics of the insert iterator guarantee that it will try and
2110   insert after the element after that, which will never be correct.
2111   However, if the container first tried to insert before the hint,
2112   all insertions would be performed in amortized constant
2113   time.</p>
2114</li>
2115</ol>
2116<p><b>Proposed resolution:</b></p>
2117<p>In 23.1.2 [lib.associative.reqmts] paragraph 7, table 69, make
2118the following changes in the row for a.insert(p,t):</p>
2119
2120<p><i>assertion/note pre/post condition:</i>
2121<br>Change the last sentence from</p>
2122     <blockquote>
2123     "iterator p is a hint pointing to where the insert should
2124     start to search."
2125     </blockquote>
2126<p>to</p>
2127     <blockquote>
2128     "iterator p is a hint indicating that immediately before p
2129     may be a correct location where the insertion could occur."
2130     </blockquote>
2131
2132<p><i>complexity:</i><br>
2133Change the words "right after" to "immediately before".</p>
2134<p><b>Rationale:</b></p>
2135<p>Duplicate; see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#233">233</a>.</p>
2136<hr>
2137<a name="249"><h3>249.&nbsp;Return Type of <tt>auto_ptr::operator=</tt>
2138</h3></a><p><b>Section:</b>&nbsp;20.4.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary"> [lib.meta.unary]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Joseph Gottman&nbsp; <b>Date:</b>&nbsp;30 Jun 2000</p>
2139<p>According to section 20.4.5, the function
2140<tt>auto_ptr::operator=()</tt> returns a reference to an auto_ptr.
2141The reason that <tt>operator=()</tt> usually returns a reference is to
2142facilitate code like</p>
2143
2144<pre>    int x,y,z;
2145    x = y = z = 1;
2146</pre>
2147
2148<p>However, given analogous code for <tt>auto_ptr</tt>s,</p>
2149<pre>    auto_ptr&lt;int&gt; x, y, z;
2150    z.reset(new int(1));
2151    x = y = z;
2152</pre>
2153
2154<p>the result would be that <tt>z</tt> and <tt>y</tt> would both be set to
2155NULL, instead of all the <tt>auto_ptr</tt>s being set to the same value.
2156This makes such cascading assignments useless and counterintuitive for
2157<tt>auto_ptr</tt>s.</p>
2158<p><b>Proposed resolution:</b></p>
2159<p>Change <tt>auto_ptr::operator=()</tt> to return <tt>void</tt> instead
2160of an <tt>auto_ptr</tt> reference.</p>
2161<p><b>Rationale:</b></p>
2162<p>The return value has uses other than cascaded assignments: a user can
2163call an auto_ptr member function, pass the auto_ptr to a
2164function, etc.  Removing the return value could break working user
2165code.</p>
2166<hr>
2167<a name="257"><h3>257.&nbsp;STL functional object and iterator inheritance.</h3></a><p><b>Section:</b>&nbsp;20.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple.tuple"> [lib.tuple.tuple]</a>, 24.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.basic"> [lib.iterator.basic]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Robert Dick &nbsp; <b>Date:</b>&nbsp;17 Aug 2000</p>
2168<p>
2169According to the November 1997 Draft Standard, the results of deleting an
2170object of a derived class through a pointer to an object of its base class are
2171undefined if the base class has a non-virtual destructor.  Therefore, it is
2172potentially dangerous to publicly inherit from such base classes.
2173</p>
2174
2175<p>Defect:
2176<br>
2177The STL design encourages users to publicly inherit from a number of classes
2178which do nothing but specify interfaces, and which contain non-virtual
2179destructors.
2180</p>
2181
2182<p>Attribution:
2183<br>
2184Wil Evers and William E. Kempf suggested this modification for functional
2185objects.
2186</p>
2187<p><b>Proposed resolution:</b></p>
2188<p>
2189When a base class in the standard library is useful only as an interface
2190specifier, i.e., when an object of the class will never be directly
2191instantiated, specify that the class contains a protected destructor.  This
2192will prevent deletion through a pointer to the base class without performance,
2193or space penalties (on any implementation I'm aware of).
2194</p>
2195
2196<p>
2197As an example, replace...
2198</p>
2199
2200<pre>    template &lt;class Arg, class Result&gt;
2201    struct unary_function {
2202            typedef Arg    argument_type;
2203            typedef Result result_type;
2204    };
2205</pre>
2206
2207<p>
2208... with...
2209</p>
2210
2211<pre>    template &lt;class Arg, class Result&gt;
2212    struct unary_function {
2213            typedef Arg    argument_type;
2214            typedef Result result_type;
2215    protected:
2216            ~unary_function() {}
2217    };
2218</pre>
2219
2220<p>
2221Affected definitions:
2222<br>
2223  &nbsp;20.3.1 [lib.function.objects] -- unary_function, binary_function
2224  <br>
2225  &nbsp;24.3.2 [lib.iterator.basic] -- iterator
2226</p>
2227<p><b>Rationale:</b></p>
2228<p>
2229The standard is clear as written; this is a request for change, not a
2230defect in the strict sense.  The LWG had several different objections
2231to the proposed change.  One is that it would prevent users from
2232creating objects of type <tt>unary_function</tt> and
2233<tt>binary_function</tt>.  Doing so can sometimes be legitimate, if users
2234want to pass temporaries as traits or tag types in generic code.
2235</p>
2236<hr>
2237<a name="267"><h3>267.&nbsp;interaction of strstreambuf::overflow() and seekoff()</h3></a><p><b>Section:</b>&nbsp;D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;5 Oct 2000</p>
2238<p>
2239It appears that the interaction of the strstreambuf members overflow()
2240and seekoff() can lead to undefined behavior in cases where defined
2241behavior could reasonably be expected. The following program
2242demonstrates this behavior:
2243</p>
2244
2245<pre>    #include &lt;strstream&gt;
2246
2247    int main ()
2248    {
2249         std::strstreambuf sb;
2250         sb.sputc ('c');
2251
2252         sb.pubseekoff (-1, std::ios::end, std::ios::in);
2253         return !('c' == sb.sgetc ());
2254    }
2255</pre>
2256
2257<p>
2258D.7.1.1, p1 initializes strstreambuf with a call to basic_streambuf&lt;&gt;(),
2259which in turn sets all pointers to 0 in 27.5.2.1, p1.
2260</p>
2261
2262<p>
226327.5.2.2.5, p1 says that basic_streambuf&lt;&gt;::sputc(c) calls
2264overflow(traits::to_int_type(c)) if a write position isn't available (it
2265isn't due to the above).
2266</p>
2267
2268<p>
2269D.7.1.3, p3 says that strstreambuf::overflow(off, ..., ios::in) makes at
2270least one write position available (i.e., it allows the function to make
2271any positive number of write positions available).
2272</p>
2273
2274<p>
2275D.7.1.3, p13 computes newoff = seekhigh - eback(). In D.7.1, p4 we see
2276seekhigh = epptr() ? epptr() : egptr(), or seekhigh = epptr() in this
2277case. newoff is then epptr() - eback().
2278</p>
2279
2280<p>
2281D.7.1.4, p14 sets gptr() so that gptr() == eback() + newoff + off, or
2282gptr() == epptr() + off holds.
2283</p>
2284
2285<p>
2286If strstreambuf::overflow() made exactly one write position available
2287then gptr() will be set to just before epptr(), and the program will
2288return 0. Buf if the function made more than one write position
2289available, epptr() and gptr() will both point past pptr() and the
2290behavior of the program is undefined.
2291</p>
2292<p><b>Proposed resolution:</b></p>
2293
2294
2295   <p>Change the last sentence of D.7.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf"> [depr.strstreambuf]</a> paragraph 4 from</p>
2296
2297      <blockquote>
2298      Otherwise, seeklow equals gbeg and seekhigh is either pend, if
2299      pend is not a null pointer, or gend.
2300      </blockquote>
2301
2302   <p>to become</p>
2303
2304      <blockquote>
2305      Otherwise, seeklow equals gbeg and seekhigh is either gend if
2306      0 == pptr(), or pbase() + max where max is the maximum value of
2307      pptr() - pbase() ever reached for this stream.
2308      </blockquote>
2309
2310<p><i>[
2311  pre-Copenhagen: Dietmar provided wording for proposed resolution.
2312]</i></p>
2313
2314<p><i>[
2315  post-Copenhagen: Fixed a typo: proposed resolution said to fix
2316  4.7.1, not D.7.1.
2317]</i></p>
2318
2319<p><b>Rationale:</b></p>
2320<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
2321means 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>,
2322the library working group does not wish to invest time nailing down
2323corner cases in a deprecated feature.</p>
2324<hr>
2325<a name="269"><h3>269.&nbsp;cstdarg and unnamed parameters</h3></a><p><b>Section:</b>&nbsp;18.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.support.exception"> [lib.support.exception]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;J. Stephen Adamczyk&nbsp; <b>Date:</b>&nbsp;10 Oct 2000</p>
2326<p>
2327One of our customers asks whether this is valid C++:
2328</p>
2329
2330<pre>   #include &lt;cstdarg&gt;
2331
2332   void bar(const char *, va_list);
2333
2334   void
2335   foo(const char *file, const char *, ...)
2336   {
2337     va_list ap;
2338     va_start(ap, file);
2339     bar(file, ap);
2340     va_end(ap);
2341   }
2342</pre>
2343
2344<p>
2345The issue being whether it is valid to use cstdarg when the final
2346parameter before the "..." is unnamed.  cstdarg is, as far
2347as I can tell, inherited verbatim from the C standard. and the
2348definition there (7.8.1.1 in the ISO C89 standard) refers to "the
2349identifier of the rightmost parameter".  What happens when there
2350is no such identifier?
2351</p>
2352
2353<p>
2354My personal opinion is that this should be allowed, but some tweak
2355might be required in the C++ standard.
2356</p>
2357<p><b>Proposed resolution:</b></p>
2358<p><b>Rationale:</b></p>
2359<p>
2360Not a defect, the C and C++ standards are clear.  It is impossible to
2361use varargs if the parameter immediately before "..." has no
2362name, because that is the parameter that must be passed to va_start.
2363The example given above is broken, because va_start is being passed
2364the wrong parameter.
2365</p>
2366
2367<p>
2368There is no support for extending varargs to provide additional
2369functionality beyond what's currently there.  For reasons of C/C++
2370compatibility, it is especially important not to make gratuitous
2371changes in this part of the C++ standard.  The C committee has already
2372been requested not to touch this part of the C standard unless
2373necessary.
2374</p>
2375<hr>
2376<a name="277"><h3>277.&nbsp;Normative encouragement in allocator requirements unclear</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;07 Nov 2000</p>
2377<p>
2378In 20.1.5, paragraph 5, the standard says that "Implementors are
2379encouraged to supply libraries that can accept allocators that
2380encapsulate more general memory models and that support non-equal
2381instances." This is intended as normative encouragement to
2382standard library implementors.  However, it is possible to interpret
2383this sentence as applying to nonstandard third-party libraries.
2384</p>
2385<p><b>Proposed resolution:</b></p>
2386<p>
2387In 20.1.5, paragraph 5, change "Implementors" to
2388"Implementors of the library described in this International
2389Standard".
2390</p>
2391<p><b>Rationale:</b></p>
2392<p>The LWG believes the normative encouragement is already
2393sufficiently clear, and that there are no important consequences
2394even if it is misunderstood.</p>
2395<hr>
2396<a name="279"><h3>279.&nbsp;const and non-const iterators should have equivalent typedefs</h3></a><p><b>Section:</b>&nbsp;23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Cleary&nbsp; <b>Date:</b>&nbsp;27 Nov 2000</p>
2397
2398<p>
2399This came from an email from Steve Cleary to Fergus in reference to
2400issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#179">179</a>. The library working group briefly discussed
2401this in Toronto and believes it should be a separate issue.
2402</p>
2403
2404<p>
2405Steve said: "We may want to state that the const/non-const iterators must have
2406the same difference type, size_type, and category."
2407</p>
2408
2409<p>
2410(Comment from Judy)
2411I'm not sure if the above sentence should be true for all
2412const and non-const iterators in a particular container, or if it means
2413the container's iterator can't be compared with the container's
2414const_iterator unless the above it true. I suspect the former.
2415</p>
2416<p><b>Proposed resolution:</b></p>
2417<p>
2418In <b>Section:</b> 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>,
2419table 65, in the assertion/note pre/post condition for X::const_iterator,
2420add the following:
2421</p>
2422
2423<blockquote>
2424<p>
2425typeid(X::const_iterator::difference_type) == typeid(X::iterator::difference_type)
2426</p>
2427
2428<p>
2429typeid(X::const_iterator::size_type) == typeid(X::iterator::size_type)
2430</p>
2431
2432<p>
2433typeid(X::const_iterator::category) == typeid(X::iterator::category)
2434</p>
2435</blockquote>
2436<p><b>Rationale:</b></p>
2437<p>Going through the types one by one: Iterators don't have a
2438<tt>size_type</tt>.  We already know that the difference types are
2439identical, because the container requirements already say that the
2440difference types of both X::iterator and X::const_iterator are both
2441X::difference_type.  The standard does not require that X::iterator
2442and X::const_iterator have the same iterator category, but the LWG
2443does not see this as a defect: it's possible to imagine cases in which
2444it would be useful for the categories to be different.</p>
2445
2446<p>It may be desirable to require X::iterator and X::const_iterator to
2447have 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>
2448
2449<hr>
2450<a name="287"><h3>287.&nbsp;conflicting ios_base fmtflags</h3></a><p><b>Section:</b>&nbsp;27.4.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fmtflags.state"> [lib.fmtflags.state]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;30 Dec 2000</p>
2451<p>
2452The Effects clause for ios_base::setf(fmtflags fmtfl) says
2453"Sets fmtfl in flags()".  What happens if the user first calls
2454ios_base::scientific and then calls ios_base::fixed or vice-versa?
2455This is an issue for all of the conflicting flags, i.e. ios_base::left
2456and ios_base::right or ios_base::dec, ios_base::hex and ios_base::oct.
2457</p>
2458
2459<p>
2460I see three possible solutions:
2461</p>
2462
2463<ol>
2464<li>Set ios_base::failbit whenever the user specifies a conflicting
2465flag with one previously explicitly set. If the constructor is
2466supposed to set ios_base::dec (see discussion below), then
2467the user setting hex or oct format after construction will not
2468set failbit. </li>
2469<li>The last call to setf "wins", i.e. it clears any conflicting
2470previous setting.</li>
2471<li>All the flags that the user specifies are set, but when actually
2472interpreting them, fixed always override scientific, right always
2473overrides left, dec overrides hex which overrides oct.</li>
2474</ol>
2475
2476<p>
2477Most existing implementations that I tried seem to conform to resolution #3,
2478except that when using the iomanip manipulator hex or oct then that always
2479overrides dec, but calling setf(ios_base::hex) doesn't.
2480</p>
2481
2482<p>
2483There is a sort of related issue, which is that although the ios_base
2484constructor says that each ios_base member has an indeterminate value
2485after construction, all the existing implementations I tried explicitly set
2486ios_base::dec.
2487</p>
2488<p><b>Proposed resolution:</b></p>
2489<p><b>Rationale:</b></p>
2490<p>
2491<tt>adjustfield</tt>, <tt>basefield</tt>, and <tt>floatfield</tt>
2492are each multi-bit fields.  It is possible to set multiple bits within
2493each of those fields.  (For example, <tt>dec</tt> and
2494<tt>oct</tt>). These fields are used by locale facets.  The LWG
2495reviewed the way in which each of those three fields is used, and
2496believes that in each case the behavior is well defined for any
2497possible combination of bits.  See for example Table 58, in 22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>, noting the requirement in paragraph 6 of that
2498section.
2499</p>
2500<p>
2501Users are advised to use manipulators, or else use the two-argument
2502version of <tt>setf</tt>, to avoid unexpected behavior.
2503</p>
2504<hr>
2505<a name="289"><h3>289.&nbsp;&lt;cmath&gt; requirements missing C float and long double versions</h3></a><p><b>Section:</b>&nbsp;26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;30 Dec 2000</p>
2506<p>
2507    In ISO/IEC 9899:1990 Programming Languages C we find the following
2508    concerning &lt;math.h&gt;:
2509</p>
2510
2511<blockquote>
2512         7.13.4 Mathematics &lt;math.h&gt;
2513         <br>
2514         The names of all existing functions declared in the &lt;math.h&gt;
2515         header, suffixed with f or l, are reserved respectively for
2516         corresponding functions with float and long double arguments
2517         are return values.
2518</blockquote>
2519
2520<p>
2521    For example, <tt>float&nbsp;sinf(float)</tt>
2522    is reserved.
2523</p>
2524
2525<p>
2526    In the C99 standard, &lt;math.h&gt; must contain declarations
2527    for these functions.
2528</p>
2529
2530<p>
2531So, is it acceptable for an implementor to add these prototypes to the
2532C++ versions of the math headers? Are they required?
2533</p>
2534<p><b>Proposed resolution:</b></p>
2535<p>
2536Add these Functions to Table 80, section 26.5 and to Table 99,
2537section C.2:
2538</p>
2539
2540<pre>    acosf asinf atanf atan2f ceilf cosf coshf
2541    expf fabsf floorf fmodf frexpf ldexpf
2542    logf log10f modff powf sinf sinhf sqrtf
2543    tanf tanhf
2544    acosl asinl atanl atan2l ceill cosl coshl
2545    expl fabsl floorl fmodl frexpl ldexpl
2546    logl log10l modfl powl sinl sinhl sqrtl
2547    tanl tanhl
2548</pre>
2549
2550<p>
2551There should probably be a note saying that these functions
2552are optional and, if supplied, should match the description in
2553the 1999 version of the C standard. In the next round
2554of C++ standardization they can then become mandatory.
2555</p>
2556<p><b>Rationale:</b></p>
2557<p>The C90 standard, as amended, already permits (but does not
2558require) these functions, and the C++ standard incorporates the
2559C90 standard by reference.  C99 is not an issue, because it is
2560never referred to by the C++ standard.</p>
2561<hr>
2562<a name="293"><h3>293.&nbsp;Order of execution in transform algorithm</h3></a><p><b>Section:</b>&nbsp;25.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.transform"> [lib.alg.transform]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;04 Jan 2001</p>
2563<p>This issue is related to issue 242.  In case that the resolution
2564proposed for issue 242 is accepted, we have have the following
2565situation: The 4 numeric algorithms (accumulate and consorts) as well
2566as transform would allow a certain category of side effects.  The
2567numeric algorithms specify that they invoke the functor "for
2568every iterator i in the range [first, last) in order". transform,
2569in contrast, would not give any guarantee regarding order of
2570invocation of the functor, which means that the functor can be invoked
2571in any arbitrary order.
2572</p>
2573
2574<p>Why would that be a problem?  Consider an example: say the
2575transformator that is a simple enumerator ( or more generally
2576speaking, "is order-sensitive" ).  Since a standard
2577compliant implementation of transform is free to invoke the enumerator
2578in no definite order, the result could be a garbled enumeration.
2579Strictly speaking this is not a problem, but it is certainly at odds
2580with the prevalent understanding of transform as an algorithms that
2581assigns "a new _corresponding_ value" to the output
2582elements.
2583</p>
2584
2585<p>All implementations that I know of invoke the transformator in
2586definite order, namely starting from first and proceeding to last -
25871. Unless there is an optimization conceivable that takes advantage of
2588the indefinite order I would suggest to specify the order, because it
2589eliminate the uncertainty that users would otherwise have regarding
2590the order of execution of their potentially order-sensitive function
2591objects.
2592</p>
2593<p><b>Proposed resolution:</b></p>
2594<p>In section 25.2.3 - Transform [lib.alg.transform] change:</p>
2595<blockquote>
2596-1- Effects: Assigns through every iterator i in the range [result,
2597result + (last1 - first1)) a new corresponding
2598value equal to op(*(first1 + (i - result)) or binary_op(*(first1 +
2599(i - result), *(first2 + (i - result))).
2600</blockquote>
2601<p>to:</p>
2602<blockquote>
2603-1- Effects: Computes values by  invoking the operation op or binary_op
2604for every iterator in the range [first1, last1) in order. Assigns through
2605every iterator i in the range [result, result + (last1 - first1)) a new
2606corresponding
2607value equal to op(*(first1 + (i - result)) or binary_op(*(first1 +
2608(i - result), *(first2 + (i - result))).
2609</blockquote>
2610<p><b>Rationale:</b></p>
2611<p>For Input Iterators an order is already guaranteed, because
2612only one order is possible.  If a user who passes a Forward
2613Iterator to one of these algorithms really needs a specific
2614order of execution, it's possible to achieve that effect by
2615wrapping it in an Input Iterator adaptor.</p>
2616<hr>
2617<a name="296"><h3>296.&nbsp;Missing descriptions and requirements of pair operators</h3></a><p><b>Section:</b>&nbsp;20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;14 Jan 2001</p>
2618<p>The synopsis of the header <tt>&lt;utility&gt;</tt> in 20.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.utility"> [lib.utility]</a>
2619lists the complete set of equality and relational operators for <tt>pair</tt>
2620but the section describing the template and the operators only describes
2621<tt>operator==()</tt> and <tt>operator&lt;()</tt>, and it fails to mention
2622any requirements on the template arguments. The remaining operators are
2623not mentioned at all.
2624</p>
2625<p><b>Proposed resolution:</b></p>
2626<p><b>Rationale:</b></p>
2627<p>20.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.operators"> [lib.operators]</a> paragraph 10 already specifies the semantics.
2628That paragraph says that, if declarations of operator!=, operator&gt;,
2629operator&lt;=, and operator&gt;= appear without definitions, they are
2630defined as specified in 20.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.operators"> [lib.operators]</a>.  There should be no user
2631confusion, since that paragraph happens to immediately precede the
2632specification of <tt>pair</tt>.</p>
2633<hr>
2634<a name="302"><h3>302.&nbsp;Need error indication from codecvt&lt;&gt;::do_length</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Gregory Bumgardner&nbsp; <b>Date:</b>&nbsp;25 Jan 2001</p>
2635<p>
2636The effects of <tt>codecvt&lt;&gt;::do_length()</tt> are described in
263722.2.1.5.2, paragraph 10.  As implied by that paragraph, and clarified
2638in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#75">75</a>, <tt>codecvt&lt;&gt;::do_length()</tt> must
2639process the source data and update the <tt>stateT</tt> argument just
2640as if the data had been processed by <tt>codecvt&lt;&gt;::in()</tt>.
2641However, the standard does not specify how <tt>do_length()</tt> would
2642report a translation failure, should the source sequence contain
2643untranslatable or illegal character sequences.
2644</p>
2645
2646<p>
2647The other conversion methods return an "error" result value
2648to indicate that an untranslatable character has been encountered, but
2649<tt>do_length()</tt> already has a return value (the number of source
2650characters that have been processed by the method).
2651</p>
2652<p><b>Proposed resolution:</b></p>
2653<p>
2654This issue cannot be resolved without modifying the interface. An exception
2655cannot be used, as there would be no way to determine how many characters
2656have been processed and the state object would be left in an indeterminate
2657state.
2658</p>
2659
2660<p>
2661A source compatible solution involves adding a fifth argument to length()
2662and do_length() that could be used to return position of the offending
2663character sequence. This argument would have a default value that would
2664allow it to be ignored:
2665</p>
2666
2667<pre>  int length(stateT&amp; state,
2668             const externT* from,
2669             const externT* from_end,
2670             size_t max,
2671             const externT** from_next = 0);
2672
2673  virtual
2674  int do_length(stateT&amp; state,
2675                const externT* from,
2676                const externT* from_end,
2677                size_t max,
2678                const externT** from_next);
2679</pre>
2680
2681<p>
2682Then an exception could be used to report any translation errors and
2683the from_next argument, if used, could then be used to retrieve the
2684location of the offending character sequence.
2685</p>
2686<p><b>Rationale:</b></p>
2687<p>The standard is already clear: the return value is the number of
2688"valid complete characters".  If it encounters an invalid sequence of
2689external characters, it stops.</p>
2690<hr>
2691<a name="304"><h3>304.&nbsp;Must <tt>*a</tt> return an lvalue when <tt>a</tt> is an input iterator?</h3></a><p><b>Section:</b>&nbsp;24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;5 Feb 2001</p>
2692<p>
2693We all "know" that input iterators are allowed to produce
2694values when dereferenced of which there is no other in-memory copy.
2695</p>
2696
2697<p>
2698But: Table 72, with a careful reading, seems to imply that this can only be
2699the case if the value_type has no members (e.g. is a built-in type).
2700</p>
2701
2702<p>The problem occurs in the following entry:</p>
2703
2704<pre>  a-&gt;m     pre: (*a).m is well-defined
2705           Equivalent to (*a).m
2706</pre>
2707
2708<p>
2709<tt>*a.m</tt> can be well-defined if <tt>*a</tt> is not a reference
2710type, but since <tt>operator-&gt;()</tt> must return a pointer for
2711<tt>a-&gt;m</tt> to be well-formed, it needs something to return a
2712pointer <i>to</i>. This seems to indicate that <tt>*a</tt> must be
2713buffered somewhere to make a legal input iterator.
2714</p>
2715
2716<p>I don't think this was intentional.</p>
2717<p><b>Proposed resolution:</b></p>
2718<p><b>Rationale:</b></p>
2719<p>The current standard is clear and consistent.  Input iterators that
2720  return rvalues are in fact implementable.  They may in some cases
2721  require extra work, but it is still possible to define an operator-&gt;
2722  in such cases: it doesn't have to return a T*, but may return a
2723  proxy type.  No change to the standard is justified.</p>
2724<hr>
2725<a name="313"><h3>313.&nbsp;set_terminate and set_unexpected question</h3></a><p><b>Section:</b>&nbsp;18.7.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.terminate"> [lib.terminate]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;3 Apr 2001</p>
2726<p>
2727According to section 18.7.3.3 of the standard, std::terminate() is
2728supposed to call the terminate_handler in effect immediately after
2729evaluating the throw expression.
2730</p>
2731
2732<p>
2733Question: what if the terminate_handler in effect is itself
2734std::terminate?
2735</p>
2736
2737<p>For example:</p>
2738
2739<pre>  #include &lt;exception&gt;
2740
2741  int main () {
2742      std::set_terminate(std::terminate);
2743      throw 5;
2744      return 0;
2745  }
2746</pre>
2747
2748<p>
2749Is the implementation allowed to go into an infinite loop?
2750</p>
2751
2752<p>
2753I think the same issue applies to std::set_unexpected.
2754</p>
2755<p><b>Proposed resolution:</b></p>
2756<p><b>Rationale:</b></p>
2757<p>Infinite recursion is to be expected: users who set the terminate
2758handler to <tt>terminate</tt> are explicitly asking for <tt>terminate</tt>
2759to call itself.</p>
2760<hr>
2761<a name="314"><h3>314.&nbsp;Is the stack unwound when terminate() is called?</h3></a><p><b>Section:</b>&nbsp;18.7.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.terminate"> [lib.terminate]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Detlef Vollmann&nbsp; <b>Date:</b>&nbsp;11 Apr 2001</p>
2762
2763<p>
2764The standard appears to contradict itself about whether the stack is
2765unwound when the implementation calls terminate().
2766</p>
2767
2768<p>From 18.7.3.3p2:</p>
2769<blockquote>
2770    Calls the terminate_handler function in effect immediately
2771    after evaluating the throw-expression (lib.terminate.handler),
2772    if called by the implementation [...]
2773</blockquote>
2774
2775<p>So the stack is guaranteed not to be unwound.</p>
2776
2777<p>But from 15.3p9:</p>
2778<blockquote>
2779    [...]whether or not the stack is unwound before this call
2780    to terminate() is implementation-defined (except.terminate).
2781</blockquote>
2782
2783<p>
2784And 15.5.1 actually defines that in most cases the stack is unwound.
2785</p>
2786<p><b>Proposed resolution:</b></p>
2787<p><b>Rationale:</b></p>
2788<p>There is definitely no contradiction between the core and library
2789clauses; nothing in the core clauses says that stack unwinding happens
2790after <tt>terminate</tt> is called.  18.7.3.3p2 does not say anything
2791about when terminate() is called; it merely specifies which
2792<tt>terminate_handler</tt> is used.</p>
2793<hr>
2794<a name="323"><h3>323.&nbsp;abs() overloads in different headers</h3></a><p><b>Section:</b>&nbsp;26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;4 June 2001</p>
2795<p>Currently the standard mandates the following overloads of
2796abs():</p>
2797
2798<pre>    abs(long), abs(int) in &lt;cstdlib&gt;
2799
2800    abs(float), abs(double), abs(long double) in &lt;cmath&gt;
2801
2802    template&lt;class T&gt; T abs(const complex&lt;T&gt;&amp;) in &lt;complex&gt;
2803
2804    template&lt;class T&gt; valarray&lt;T&gt; abs(const valarray&lt;T&gt;&amp;); in &lt;valarray&gt;
2805</pre>
2806
2807<p>
2808The problem is that having only some overloads visible of a function
2809that works on "implicitly inter-convertible" types is dangerous in
2810practice. The headers that get included at any point in a translation
2811unit can change unpredictably during program
2812development/maintenance. The wrong overload might be unintentionally
2813selected.
2814</p>
2815
2816<p>
2817Currently, there is nothing that mandates the simultaneous visibility
2818of these overloads. Indeed, some vendors have begun fastidiously
2819reducing dependencies among their (public) headers as a QOI issue: it
2820helps people to write portable code by refusing to compile unless all
2821the correct headers are #included.
2822</p>
2823
2824<p>The same issue may exist for other functions in the library.</p>
2825
2826<p>Redmond: PJP reports that C99 adds two new kinds of abs: complex,
2827and int_max_abs.</p>
2828
2829<p>Related issue: <font color="red">343</font>.</p>
2830
2831<p><b>Proposed resolution:</b></p>
2832<p><b>Rationale:</b></p>
2833<p>The programs that could potentially be broken by this situation are
2834  already fragile, and somewhat contrived: For example, a user-defined
2835  class that has conversion overloads both to <tt>long</tt> and
2836  to <tt>float</tt>.  If <tt>x</tt> is a value of such a class, then
2837  <tt>abs(x)</tt> would give the <tt>long</tt> version if the user
2838  included &lt;cstdlib&gt;, the <tt>float</tt> version if the user
2839  included &lt;cmath&gt;, and would be diagnosed as ambiguous at
2840  compile time if the user included both headers.  The LWG couldn't
2841  find an example of a program whose meaning would be changed (as
2842  opposed to changing it from well-formed to ill-formed) simply by
2843  adding another standard header.</p>
2844
2845<p>Since the harm seems minimal, and there don't seem to be any simple
2846  and noninvasive solutions, this is being closed as NAD.  It is
2847  marked as "Future" for two reasons.  First, it might be useful to
2848  define an <tt>&lt;all&gt;</tt> header that would include all
2849  Standard Library headers.  Second, we should at least make sure that
2850  future library extensions don't make this problem worse.</p>
2851<hr>
2852<a name="326"><h3>326.&nbsp;Missing typedef in moneypunct_byname</h3></a><p><b>Section:</b>&nbsp;22.2.6.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.byname"> [lib.locale.moneypunct.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;05 Jul 2001</p>
2853<p>The definition of the moneypunct facet contains the typedefs char_type
2854and string_type. Only one of these names, string_type, is defined in
2855the derived facet, moneypunct_byname.</p>
2856<p><b>Proposed resolution:</b></p>
2857<p>For consistency with the numpunct facet, add a typedef for
2858char_type to the definition of the moneypunct_byname facet in
285922.2.6.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.byname"> [lib.locale.moneypunct.byname]</a>.</p>
2860<p><b>Rationale:</b></p>
2861<p>The absence of the typedef is irrelevant.  Users can still access
2862the typedef, because it is inherited from the base class.</p>
2863<hr>
2864<a name="330"><h3>330.&nbsp;Misleading "exposition only" value in class locale definition</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Jul 2001</p>
2865<p>
2866The "exposition only" value of the std::locale::none constant shown in
2867the definition of class locale is misleading in that it on many
2868systems conflicts with the value assigned to one if the LC_XXX
2869constants (specifically, LC_COLLATE on AIX, LC_ALL on HP-UX, LC_CTYPE
2870on Linux and SunOS). This causes incorrect behavior when such a
2871constant is passed to one of the locale member functions that accept a
2872locale::category argument and interpret it as either the C LC_XXX
2873constant or a bitmap of locale::category values. At least three major
2874implementations adopt the suggested value without a change and
2875consequently suffer from this problem.
2876</p>
2877
2878<p>
2879For instance, the following code will (presumably) incorrectly copy facets
2880belonging to the collate category from the German locale on AIX:
2881</p>
2882
2883<pre>  std::locale l (std::locale ("C"), "de_DE", std::locale::none);
2884</pre>
2885<p><b>Proposed resolution:</b></p>
2886<p><b>Rationale:</b></p>
2887<p>The LWG agrees that it may be difficult to implement locale member
2888functions in such a way that they can take either <tt>category</tt>
2889arguments or the LC_ constants defined in &lt;cctype&gt;.  In light of
2890this requirement (22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>, paragraph 2), and in light
2891of the requirement in the preceding paragraph that it is possible to
2892combine <tt>category</tt> bitmask elements with bitwise operations,
2893defining the <tt>category</tt> elements is delicate,
2894particularly if an implementor is constrained to work with a
2895preexisting C library.  (Just using the existing LC_ constants would
2896not work in general.)  There's no set of "exposition only" values that
2897could give library implementors proper guidance in such a delicate
2898matter.  The non-normative example we're giving is no worse than
2899any other choice would be.</p>
2900
2901<p>See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#347">347</a>.</p>
2902<hr>
2903<a name="332"><h3>332.&nbsp;Consider adding increment and decrement operators to std::fpos&lt; T &gt; </h3></a><p><b>Section:</b>&nbsp;27.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos"> [lib.fpos]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;PremAnand M. Rao&nbsp; <b>Date:</b>&nbsp;27 Aug 2001</p>
2904<p>
2905Increment and decrement operators are missing from
2906Table 88 -- Position type requirements in 27.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos"> [lib.fpos]</a>.
2907</p>
2908<p><b>Proposed resolution:</b></p>
2909<p>
2910Table 88 (section 27.4.3) -- Position type requirements
2911be updated to include increment and decrement operators.
2912</p>
2913
2914<pre>expression        return type     operational    note
2915
2916++p               fpos&amp;           p += O(1)
2917p++               fpos            { P tmp = p;
2918                                    ++p;
2919                                    return tmp; }
2920--p               fpos&amp;           p -= O(1)
2921p--               fpos            { P tmp = p;
2922                                    --p;
2923                                    return tmp; }
2924</pre>
2925
2926<p><b>Rationale:</b></p>
2927<p>The LWG believes this is a request for extension, not a defect
2928report.  Additionally, nobody saw a clear need for this extension;
2929<tt>fpos</tt> is used only in very limited ways.</p>
2930<hr>
2931<a name="344"><h3>344.&nbsp;grouping + showbase</h3></a><p><b>Section:</b>&nbsp;22.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.category.numeric"> [lib.category.numeric]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;13 Oct 2001</p>
2932<p>
2933When both grouping and showbase are active and the basefield is octal,
2934does the leading 0 participate in the grouping or not?  For example,
2935should one format as: 0,123,456 or 0123,456?
2936</p>
2937<p>
2938An analogy can be drawn with hexadecimal.  It appears that 0x123,456 is
2939preferred over 0x,123,456.  However, this analogy is not universally
2940accepted to apply to the octal base.  The standard is not clear on how
2941to format (or parse) in this manner.
2942</p>
2943<p><b>Proposed resolution:</b></p>
2944<p>
2945Insert into 22.2.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.numpunct.virtuals"> [lib.facet.numpunct.virtuals]</a> paragraph 3, just before the last
2946sentence:
2947</p>
2948<blockquote>
2949The leading hexadecimal base specifier "0x" does not participate in
2950grouping.  The leading '0' octal base specifier may participate in
2951grouping.  It is unspecified if the leading '0' participates in
2952formatting octal numbers.  In parsing octal numbers, the implementation
2953is encouraged to accept both the leading '0' participating in the
2954grouping, and not participating (e.g. 0123,456 or 0,123,456).
2955</blockquote>
2956<p><b>Rationale:</b></p>
2957<p>
2958The current behavior may be unspecified, but it's not clear that it
2959matters.  This is an obscure corner case, since grouping is usually
2960intended for the benefit of humans and oct/hex prefixes are usually
2961intended for the benefit of machines.  There is not a strong enough
2962consensus in the LWG for action.
2963</p>
2964<hr>
2965<a name="348"></a><h3><a name="348">348.&nbsp;Minor issue with std::pair operator&lt;</a></h3><p><b>Section:</b>&nbsp;20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;23 Oct 2001</p>
2966<p>
2967The current wording of 20.2.2 [lib.pairs] p6 precludes the use of
2968operator&lt; on any pair type which contains a pointer.
2969</p>
2970<p><b>Proposed resolution:</b></p>
2971<p>In 20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a> paragraph 6, replace:</p>
2972<pre>    Returns: x.first &lt; y.first || (!(y.first &lt; x.first) &amp;&amp; x.second &lt;
2973        y.second).
2974</pre>
2975<p>With:</p>
2976<pre>    Returns: std::less&lt;T1&gt;()( x.first, y.first ) ||
2977             (!std::less&lt;T1&gt;()( y.first, x.first) &amp;&amp;
2978             std::less&lt;T2&gt;()( x.second, y.second ) )
2979</pre>
2980
2981<p><b>Rationale:</b></p>
2982<p>This is an instance of a much more general problem.  If we want
2983  operator&lt; to translate to std::less for pairs of pointers, where
2984  do we draw the line?  The same issue applies to individual
2985  pointers, smart pointer wrappers, std::vector&lt;T*&gt;, and so
2986  on.</p>
2987
2988<p>Andy Koenig suggests that the real issue here is that we aren't
2989  distinguishing adequately between two different orderings, a
2990  "useful ordering" and a "canonical ordering" that's used just
2991  because we sometimes need <i>some</i> ordering without caring much
2992  which ordering it is.  Another example of the later is typeinfo's
2993  <tt>before</tt>.</p>
2994
2995<hr>
2996<a name="350"><h3>350.&nbsp;allocator&lt;&gt;::address</h3></a><p><b>Section:</b>&nbsp;20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a>, 20.1.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.requirements"> [lib.allocator.requirements]</a>, 17.4.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.contents"> [lib.contents]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;25 Oct 2001</p>
2997<p>See c++std-lib-9006 and c++std-lib-9007.  This issue is taken
2998verbatim from -9007.</p>
2999
3000<p>
3001The core language feature allowing definition of operator&amp;() applied
3002to any non-builtin type makes that operator often unsafe to use in
3003implementing libraries, including the Standard Library.  The result
3004is that many library facilities fail for legal user code, such as
3005the fragment</p>
3006<pre>  class A { private: A* operator&amp;(); };
3007  std::vector&lt;A&gt; aa;
3008
3009  class B { };
3010  B* operator&amp;(B&amp;) { return 0; }
3011  std::vector&lt;B&gt; ba;
3012</pre>
3013
3014<p>
3015In particular, the requirements table for Allocator (Table 32) specifies
3016no semantics at all for member address(), and allocator&lt;&gt;::address is
3017defined in terms of unadorned operator &amp;.
3018</p>
3019
3020<p><b>Proposed resolution:</b></p>
3021<p>
3022In 20.6.1.1, Change the definition of allocator&lt;&gt;::address from:</p>
3023<blockquote>
3024  Returns: &amp;x
3025</blockquote>
3026
3027<p>to:</p>
3028
3029<p>
3030  Returns: The value that the built in operator&amp;(x) would return if not
3031  overloaded.
3032</p>
3033
3034<p>
3035In 20.1.6, Table 32, add to the Notes column of the a.address(r) and
3036a.address(s) lines, respectively:
3037</p>
3038
3039<pre>  allocator&lt;T&gt;::address(r)
3040  allocator&lt;T&gt;::address(s)
3041</pre>
3042
3043<p>In addition, in clause 17.4.1.1, add a statement:</p>
3044
3045<blockquote>
3046 The Standard Library does not apply operator&amp; to any type for which
3047 operator&amp; may be overloaded.
3048</blockquote>
3049
3050<p><b>Rationale:</b></p>
3051<p>The LWG believes both examples are ill-formed.  The contained type
3052is required to be CopyConstructible (20.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.copyconstructible"> [lib.copyconstructible]</a>), and that
3053includes the requirement that &amp;t return the usual types and
3054values. Since allocators are intended to be used in conjunction with
3055containers, and since the CopyConstructible requirements appear to
3056have been written to deal with the concerns of this issue, the LWG
3057feels it is NAD unless someone can come up with a well-formed example
3058exhibiting a problem.</p>
3059
3060<p>It may well be that the CopyConstructible requirements are too
3061  restrictive and that either the container requirements or the
3062  CopyConstructive requirements should be relaxed, but that's a far
3063  larger issue.  Marking this issue as "future" as a pointer to that
3064  larger issue.</p>
3065<hr>
3066<a name="351"><h3>351.&nbsp;unary_negate and binary_negate: struct or class?</h3></a><p><b>Section:</b>&nbsp;20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Dale Riley&nbsp; <b>Date:</b>&nbsp;12 Nov 2001</p>
3067<p>
3068In 20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a> the header &lt;functional&gt; synopsis declares
3069the unary_negate and binary_negate function objects as struct.
3070However in <font color="red">20.3.5</font> the unary_negate and binary_negate
3071function objects are defined as class.  Given the context, they are
3072not "basic function objects" like negate, so this is either a typo or
3073an editorial oversight.
3074</p>
3075
3076<p><i>[Taken from comp.std.c++]</i></p>
3077<p><b>Proposed resolution:</b></p>
3078<p>Change the synopsis to reflect the useage in <font color="red">20.3.5</font></p>
3079
3080<p><i>[Cura�ao: Since the language permits "struct", the LWG
3081views this as NAD. They suggest, however, that the Project Editor
3082might wish to make the change as editorial.]</i></p>
3083
3084<hr>
3085<a name="353"><h3>353.&nbsp;<tt>std::pair</tt> missing template assignment</h3></a><p><b>Section:</b>&nbsp;20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;2 Dec 2001</p>
3086<p>
3087The class template <tt>std::pair</tt> defines a template ctor (20.2.2, p4) but
3088no template assignment operator. This may lead to inefficient code since
3089assigning an object of <tt>pair&lt;C, D&gt;</tt> to <tt>pair&lt;A, B&gt;</tt>
3090where the types <tt>C</tt> and <tt>D</tt> are distinct from but convertible to
3091<tt>A</tt> and <tt>B</tt>, respectively, results in a call to the template copy
3092ctor to construct an unnamed temporary of type <tt>pair&lt;A, B&gt;</tt>
3093followed by an ordinary (perhaps implicitly defined) assignment operator,
3094instead of just a straight assignment.
3095</p>
3096<p><b>Proposed resolution:</b></p>
3097<p>
3098Add the following declaration to the definition of <tt>std::pair</tt>:
3099</p>
3100<pre>    template&lt;class U, class V&gt;
3101    pair&amp; operator=(const pair&lt;U, V&gt; &amp;p);
3102</pre>
3103<p>
3104And also add a paragraph describing the effects of the function template to the
3105end of 20.2.2:
3106</p>
3107<pre>    template&lt;class U, class V&gt;
3108    pair&amp; operator=(const pair&lt;U, V&gt; &amp;p);
3109</pre>
3110<p>
3111    <b>Effects</b>: <tt>first = p.first;</tt>
3112                    <tt>second = p.second;</tt>
3113    <b>Returns</b>: <tt>*this</tt>
3114</p>
3115
3116<p><i>[Cura�ao: There is no indication this is was anything other than
3117a design decision, and thus NAD.&nbsp; May be appropriate for a future
3118standard.]</i></p>
3119
3120<hr>
3121<a name="356"><h3>356.&nbsp;Meaning of ctype_base::mask enumerators</h3></a><p><b>Section:</b>&nbsp;22.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.category.ctype"> [lib.category.ctype]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;23 Jan 2002</p>
3122
3123<p>What should the following program print?</p>
3124
3125<pre>  #include &lt;locale&gt;
3126  #include &lt;iostream&gt;
3127
3128  class my_ctype : public std::ctype&lt;char&gt;
3129  {
3130    typedef std::ctype&lt;char&gt; base;
3131  public:
3132    my_ctype(std::size_t refs = 0) : base(my_table, false, refs)
3133    {
3134      std::copy(base::classic_table(), base::classic_table() + base::table_size,
3135                my_table);
3136      my_table[(unsigned char) '_'] = (base::mask) (base::print | base::space);
3137    }
3138  private:
3139    mask my_table[base::table_size];
3140  };
3141
3142  int main()
3143  {
3144    my_ctype ct;
3145    std::cout &lt;&lt; "isspace: " &lt;&lt; ct.is(std::ctype_base::space, '_') &lt;&lt; "    "
3146              &lt;&lt; "isalpha: " &lt;&lt; ct.is(std::ctype_base::alpha, '_') &lt;&lt; std::endl;
3147  }
3148</pre>
3149
3150<p>The goal is to create a facet where '_' is treated as whitespace.</p>
3151
3152<p>On gcc 3.0, this program prints "isspace: 1 isalpha: 0".  On
3153Microsoft C++ it prints "isspace: 1 isalpha: 1".</p>
3154
3155<p>
3156I believe that both implementations are legal, and the standard does not
3157give enough guidance for users to be able to use std::ctype's
3158protected interface portably.</p>
3159
3160<p>
3161The above program assumes that ctype_base::mask enumerators like
3162<tt>space</tt> and <tt>print</tt> are disjoint, and that the way to
3163say that a character is both a space and a printing character is to or
3164those two enumerators together.  This is suggested by the "exposition
3165only" values in 22.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.category.ctype"> [lib.category.ctype]</a>, but it is nowhere specified in
3166normative text.  An alternative interpretation is that the more
3167specific categories subsume the less specific.  The above program
3168gives the results it does on the Microsoft compiler because, on that
3169compiler, <tt>print</tt> has all the bits set for each specific
3170printing character class.
3171</p>
3172
3173<p>From the point of view of std::ctype's public interface, there's no
3174important difference between these two techniques.  From the point of
3175view of the protected interface, there is.  If I'm defining a facet
3176that inherits from std::ctype&lt;char&gt;, I'm the one who defines the
3177value that table()['a'] returns.  I need to know what combination of
3178mask values I should use.  This isn't so very esoteric: it's exactly
3179why std::ctype has a protected interface.  If we care about users
3180being able to write their own ctype facets, we have to give them a
3181portable way to do it.
3182</p>
3183
3184<p>
3185Related reflector messages:
3186lib-9224, lib-9226, lib-9229, lib-9270, lib-9272, lib-9273, lib-9274,
3187lib-9277, lib-9279.
3188</p>
3189
3190<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
3191proposed resolution if issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#339">339</a> says that
3192ctype_base::mask must be a bitmask type. It does not say that the
3193ctype_base::mask elements are bitmask elements, so it doesn't
3194directly affect this issue.</p>
3195
3196<p>More comments from Benjamin Kosnik, who believes that
3197that C99 compatibility essentially requires what we're
3198calling option 1 below.</p>
3199
3200<blockquote>
3201<pre>I think the C99 standard is clear, that isspace -&gt; !isalpha.
3202--------
3203
3204#include &lt;locale&gt;
3205#include &lt;iostream&gt;
3206
3207class my_ctype : public std::ctype&lt;char&gt;
3208{
3209private:
3210  typedef std::ctype&lt;char&gt; base;
3211  mask my_table[base::table_size];
3212
3213public:
3214  my_ctype(std::size_t refs = 0) : base(my_table, false, refs)
3215  {
3216    std::copy(base::classic_table(), base::classic_table() + base::table_size,
3217              my_table);
3218    mask both = base::print | base::space;
3219    my_table[static_cast&lt;mask&gt;('_')] = both;
3220  }
3221};
3222
3223int main()
3224{
3225  using namespace std;
3226  my_ctype ct;
3227  cout &lt;&lt; "isspace: " &lt;&lt; ct.is(ctype_base::space, '_') &lt;&lt; endl;
3228  cout &lt;&lt; "isprint: " &lt;&lt; ct.is(ctype_base::print, '_') &lt;&lt; endl;
3229
3230  // ISO C99, isalpha iff upper | lower set, and !space.
3231  // 7.5, p 193
3232  // -&gt; looks like g++ behavior is correct.
3233  // 356 -&gt; bitmask elements are required for ctype_base
3234  // 339 -&gt; bitmask type required for mask
3235  cout &lt;&lt; "isalpha: " &lt;&lt; ct.is(ctype_base::alpha, '_') &lt;&lt; endl;
3236}
3237</pre>
3238</blockquote>
3239
3240<p><b>Proposed resolution:</b></p>
3241<p>Informally, we have three choices:</p>
3242<ol>
3243<li>Require that the enumerators are disjoint (except for alnum and
3244graph)</li>
3245<li>Require that the enumerators are not disjoint, and specify which
3246of them subsume which others.  (e.g. mandate that lower includes alpha
3247and print)</li>
3248<li>Explicitly leave this unspecified, which the result that the above
3249program is not portable.</li>
3250</ol>
3251
3252<p>Either of the first two options is just as good from the standpoint
3253of portability.  Either one will require some implementations to
3254change.</p>
3255<p><b>Rationale:</b></p>
3256<p>The LWG agrees that this is a real ambiguity, and that both
3257interpretations are conforming under the existing standard. However,
3258there's no evidence that it's causing problems for real users. Users
3259who want to define ctype facets portably can test the ctype_base masks
3260to see which interpretation is being used.</p>
3261<hr>
3262<a name="357"><h3>357.&nbsp;&lt;cmath&gt; float functions cannot return HUGE_VAL</h3></a><p><b>Section:</b>&nbsp;26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;26 Feb 2002</p>
3263<p>
3264The float versions of the math functions have no meaningful value to return
3265for a range error. The long double versions have a value they can return,
3266but it isn't necessarily the most reasonable value.
3267</p>
3268
3269<p>
3270Section 26.5 [lib.c.math], paragraph 5, says that C++ "adds float and long
3271double overloaded versions of these functions, with the same semantics,"
3272referring to the math functions from the C90 standard.
3273</p>
3274
3275<p>
3276The C90 standard, in section 7.5.1, paragraph 3, says that functions return
3277"the value of the macro HUGE_VAL" when they encounter a range error.
3278Section 7.5, paragraph 2, defines HUGE_VAL as a macro that "expands to a
3279positive double expression, not necessarily representable as a float."
3280</p>
3281
3282<p>
3283Therefore, the float versions of the math functions have no way to
3284signal a range error. <i>[Cura�ao: The LWG notes that this isn't
3285strictly correct, since errno is set.]</i> The semantics require that they
3286return HUGE_VAL, but they cannot because HUGE_VAL might not be
3287representable as a float.
3288</p>
3289
3290<p>
3291The problem with long double functions is less severe because HUGE_VAL is
3292representable as a long double. On the other hand, it might not be a "huge"
3293long double value, and might fall well within the range of normal return
3294values for a long double function. Therefore, it does not make sense for a
3295long double function to return a double (HUGE_VAL) for a range error.
3296</p>
3297<p><b>Proposed resolution:</b></p>
3298<p>Cura�ao: C99 was faced with a similar problem, which they fixed by
3299adding HUGE_VALF and HUGE_VALL in addition to HUGE_VAL.</p>
3300
3301<p>C++ must also fix, but it should be done in the context of the
3302general C99 based changes to C++, not via DR. Thus the LWG in Cura�ao
3303felt the resolution should be NAD, FUTURE, but the issue is being held
3304open for one more meeting to ensure LWG members not present during the
3305discussion concur.</p>
3306<p><b>Rationale:</b></p>
3307<p>Will be fixed as part of more general work in the TR.</p>
3308<hr>
3309<a name="361"><h3>361.&nbsp;num_get&lt;&gt;::do_get (..., void*&amp;) checks grouping</h3></a><p><b>Section:</b>&nbsp;22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;12 Mar 2002</p>
3310<p>
331122.2.2.2.2, p12 specifies that <tt>thousands_sep</tt> is to be inserted only
3312for integral types (issue 282 suggests that this should be done for
3313all arithmetic types).
3314</p>
3315
3316<p>
331722.2.2.1.2, p12 requires that grouping be checked for all extractors
3318including that for <tt>void*</tt>.
3319</p>
3320
3321<p>
3322I don't think that's right. <tt>void*</tt> values should not be checked for
3323grouping, should they? (Although if they should, then <tt>num_put</tt> needs
3324to write them out, otherwise their extraction will fail.)
3325</p>
3326<p><b>Proposed resolution:</b></p>
3327<p>
3328Change the first sentence of 22.2.2.2.2, p12 from
3329</p>
3330<blockquote>
3331    Digit grouping is checked. That is, the positions of discarded
3332    separators is examined for consistency with
3333    use_facet&lt;numpunct&lt;charT&gt; &gt;(loc).grouping().
3334    If they are not consistent then ios_base::failbit is assigned
3335    to err.
3336</blockquote>
3337
3338<p>to</p>
3339<blockquote>
3340    Except for conversions to void*, digit grouping is checked...
3341</blockquote>
3342
3343<p><b>Rationale:</b></p>
3344<p>This would be a change: as it stands, the standard clearly
3345  specifies that grouping applies to void*.  A survey of existing
3346  practice shows that most existing implementations do that, as they
3347  should.</p>
3348<hr>
3349<a name="366"><h3>366.&nbsp;Excessive const-qualification</h3></a><p><b>Section:</b>&nbsp;27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown, Marc Paterno&nbsp; <b>Date:</b>&nbsp;10 May 2002</p>
3350<p>
3351The following member functions are declared const, yet return non-const
3352pointers. We believe they are should be changed, because they allow code
3353that may surprise the user. See document N1360 for details and
3354rationale.
3355</p>
3356
3357<p><i>[Santa Cruz: the real issue is that we've got const member
3358functions that return pointers to non-const, and N1360 proposes
3359replacing them by overloaded pairs.  There isn't a consensus about
3360whether this is a real issue, since we've never said what our
3361constness policy is for iostreams.  N1360 relies on a distinction
3362between physical constness and logical constness; that distinction, or
3363those terms, does not appear in the standard.]</i></p>
3364
3365<p><b>Proposed resolution:</b></p>
3366<p>In 27.4.4 and 27.4.4.2</p>
3367<p>Replace</p>
3368<pre>  basic_ostream&lt;charT,traits&gt;* tie() const;
3369</pre>
3370<p>with</p>
3371<pre>  basic_ostream&lt;charT,traits&gt;* tie();
3372  const basic_ostream&lt;charT,traits&gt;* tie() const;
3373</pre>
3374
3375<p>and replace</p>
3376<pre>  basic_streambuf&lt;charT,traits&gt;* rdbuf() const;
3377</pre>
3378<p>with</p>
3379<pre>  basic_streambuf&lt;charT,traits&gt;* rdbuf();
3380  const basic_streambuf&lt;charT,traits&gt;* rdbuf() const;
3381</pre>
3382
3383<p>In 27.5.2 and 27.5.2.3.1</p>
3384<p>Replace</p>
3385<pre>  char_type* eback() const;
3386</pre>
3387<p>with</p>
3388<pre>  char_type* eback();
3389  const char_type* eback() const;
3390</pre>
3391
3392<p>Replace</p>
3393<pre>  char_type gptr() const;
3394</pre>
3395<p>with</p>
3396<pre>  char_type* gptr();
3397  const char_type* gptr() const;
3398</pre>
3399
3400<p>Replace</p>
3401<pre>  char_type* egptr() const;
3402</pre>
3403<p>with</p>
3404<pre>  char_type* egptr();
3405  const char_type* egptr() const;
3406</pre>
3407
3408<p>In 27.5.2 and 27.5.2.3.2</p>
3409<p>Replace</p>
3410<pre>  char_type* pbase() const;
3411</pre>
3412<p>with</p>
3413<pre>  char_type* pbase();
3414  const char_type* pbase() const;
3415</pre>
3416
3417<p>Replace</p>
3418<pre>  char_type* pptr() const;
3419</pre>
3420<p>with</p>
3421<pre>  char_type* pptr();
3422  const char_type* pptr() const;
3423</pre>
3424
3425<p>Replace</p>
3426<pre>  char_type* epptr() const;
3427</pre>
3428<p>with</p>
3429<pre>  char_type* epptr();
3430  const char_type* epptr() const;
3431</pre>
3432
3433<p>In 27.7.2, 27.7.2.2, 27.7.3 27.7.3.2, 27.7.4, and 27.7.6</p>
3434<p>Replace</p>
3435<pre>  basic_stringbuf&lt;charT,traits,Allocator&gt;* rdbuf() const;
3436</pre>
3437<p>with</p>
3438<pre>  basic_stringbuf&lt;charT,traits,Allocator&gt;* rdbuf();
3439  const basic_stringbuf&lt;charT,traits,Allocator&gt;* rdbuf() const;
3440</pre>
3441
3442<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>
3443<p>Replace</p>
3444<pre>  basic_filebuf&lt;charT,traits&gt;* rdbuf() const;
3445</pre>
3446<p>with</p>
3447<pre>  basic_filebuf&lt;charT,traits&gt;* rdbuf();
3448  const basic_filebuf&lt;charT,traits&gt;* rdbuf() const;
3449</pre>
3450<p><b>Rationale:</b></p>
3451<p>The existing specification is a bit sloppy, but there's no
3452  particular reason to change this other than tidiness, and there are
3453  a number of ways in which streams might have been designed
3454  differently if we were starting today.  There's no evidence that the
3455  existing constness policy is harming users.  We might consider
3456  a different constness policy as part of a full stream redesign.</p>
3457<hr>
3458<a name="367"><h3>367.&nbsp;remove_copy/remove_copy_if and Input Iterators</h3></a><p><b>Section:</b>&nbsp;25.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.remove"> [lib.alg.remove]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Anthony Williams&nbsp; <b>Date:</b>&nbsp;13 May 2002</p>
3459<p>
3460remove_copy and remove_copy_if (25.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.remove"> [lib.alg.remove]</a>) permit their
3461input range to be marked with Input Iterators. However, since two
3462operations are required against the elements to copy (comparison and
3463assigment), when the input range uses Input Iterators, a temporary
3464copy must be taken to avoid dereferencing the iterator twice. This
3465therefore requires the value type of the InputIterator to be
3466CopyConstructible. If the iterators are at least Forward Iterators,
3467then the iterator can be dereferenced twice, or a reference to the
3468result maintained, so the temporary is not required.
3469</p>
3470<p><b>Proposed resolution:</b></p>
3471<p>
3472Add "If InputIterator does not meet the requirements of forward
3473iterator, then the value type of InputIterator must be copy
3474constructible. Otherwise copy constructible is not required." to
347525.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.remove"> [lib.alg.remove]</a> paragraph 6.
3476</p>
3477<p><b>Rationale:</b></p>
3478<p>The assumption is that an input iterator can't be dereferenced
3479  twice.  There's no basis for that assumption in the Standard.</p>
3480<hr>
3481<a name="368"><h3>368.&nbsp;basic_string::replace has two "Throws" paragraphs</h3></a><p><b>Section:</b>&nbsp;21.3.5.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::replace"> [lib.string::replace]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;3 Jun 2002</p>
3482<p>
348321.3.5.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::replace"> [lib.string::replace]</a> basic_string::replace, second
3484signature, given in paragraph 1, has two "Throws" paragraphs (3 and
34855).
3486</p>
3487
3488<p>
3489In addition, the second "Throws" paragraph (5) includes specification
3490(beginning with "Otherwise, the function replaces ...") that should be
3491part of the "Effects" paragraph.
3492</p>
3493<p><b>Proposed resolution:</b></p>
3494<p><b>Rationale:</b></p>
3495<p>This is editorial. Both "throws" statements are true. The bug is
3496  just that the second one should be a sentence, part of the "Effects"
3497  clause, not a separate "Throws".  The project editor has been
3498  notified.</p>
3499<hr>
3500<a name="372"><h3>372.&nbsp;Inconsistent description of stdlib exceptions</h3></a><p><b>Section:</b>&nbsp;17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a>, 18.6.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.type.info"> [lib.type.info]</a>, &nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Randy Maddox&nbsp; <b>Date:</b>&nbsp;22 Jul 2002</p>
3501
3502<p>Paragraph 3 under clause 17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a>, Restrictions on
3503Exception Handling, states that "Any other functions defined in the
3504C++ Standard Library that do not have an exception-specification may
3505throw implementation-defined exceptions unless otherwise specified."
3506This statement is followed by a reference to footnote 178 at the
3507bottom of that page which states, apparently in reference to the C++
3508Standard Library, that "Library implementations are encouraged (but
3509not required) to report errors by throwing exceptions from (or derived
3510from) the standard exceptions."</p>
3511
3512<p>These statements appear to be in direct contradiction to clause
351318.6.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.type.info"> [lib.type.info]</a>, which states "The class exception defines the
3514base class for the types of objects thrown as exceptions by the C++
3515Standard library components ...".</p>
3516
3517<p>Is this inconsistent?</p>
3518
3519<p><b>Proposed resolution:</b></p>
3520<p><b>Rationale:</b></p>
3521<p>Clause 17 is setting the overall library requirements, and it's
3522  clear and consistent.  This sentence from Clause 18 is descriptive,
3523  not setting a requirement on any other class.
3524</p>
3525<hr>
3526<a name="374"><h3>374.&nbsp;moneypunct::frac_digits returns int not unsigned</h3></a><p><b>Section:</b>&nbsp;22.2.6.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.members"> [lib.locale.moneypunct.members]</a>, 22.2.6.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.virtuals"> [lib.locale.moneypunct.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;8 Aug 2002</p>
3527<p>
3528In section 22.2.6.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.members"> [lib.locale.moneypunct.members]</a>, frac_digits() returns type
3529"int". This implies that frac_digits() might return a negative value,
3530but a negative value is nonsensical. It should return "unsigned".
3531</p>
3532
3533<p>
3534Similarly, in section 22.2.6.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.virtuals"> [lib.locale.moneypunct.virtuals]</a>, do_frac_digits()
3535should return "unsigned".
3536</p>
3537
3538<p><b>Proposed resolution:</b></p>
3539<p><b>Rationale:</b></p>
3540<p>Regardless of whether the return value is int or unsigned, it's
3541always conceivable that frac_digits might return a nonsensical
3542value. (Is 4294967295 really any better than -1?)  The clients of
3543moneypunct, the get and put facets, can and do perform range
3544checks.</p>
3545<hr>
3546<a name="377"><h3>377.&nbsp;basic_string::insert and length_error</h3></a><p><b>Section:</b>&nbsp;21.3.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::insert"> [lib.string::insert]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;16 Aug 2002</p>
3547<p>
3548Section 21.3.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::insert"> [lib.string::insert]</a>, paragraph 4, contains the following,
3549"Then throws length_error if size() &gt;= npos - rlen."
3550</p>
3551
3552<p>
3553Related to DR 83, this sentence should probably be removed.
3554</p>
3555<p><b>Proposed resolution:</b></p>
3556<p><b>Rationale:</b></p>
3557<p>This requirement is redundant but correct.  No change is
3558needed.</p>
3559<hr>
3560<a name="378"><h3>378.&nbsp;locale immutability and locale::operator=()</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;6 Sep 2002</p>
3561<p>
3562I think there is a problem with 22.1.1, p6 which says that
3563</p>
3564<pre>    -6- An instance of locale is immutable; once a facet reference
3565        is obtained from it, that reference remains usable as long
3566        as the locale value itself exists.
3567</pre>
3568<p>
3569and 22.1.1.2, p4:
3570</p>
3571<pre>    const locale&amp; operator=(const locale&amp; other) throw();
3572
3573    -4- Effects: Creates a copy of other, replacing the current value.
3574</pre>
3575<p>
3576How can a reference to a facet obtained from a locale object remain
3577valid after an assignment that clearly must replace all the facets
3578in the locale object? Imagine a program such as this
3579</p>
3580<pre>    std::locale loc ("de_DE");
3581    const std::ctype&lt;char&gt; &amp;r0 = std::use_facet&lt;std::ctype&lt;char&gt; &gt;(loc);
3582    loc = std::locale ("en_US");
3583    const std::ctype&lt;char&gt; &amp;r1 = std::use_facet&lt;std::ctype&lt;char&gt; &gt;(loc);
3584</pre>
3585<p>
3586Is r0 really supposed to be preserved and destroyed only when loc goes
3587out of scope?
3588</p>
3589<p><b>Proposed resolution:</b></p>
3590<p><i>[Summer '04 mid-meeting mailing: Martin and Dietmar believe this
3591  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
3592  closed.
3593]</i></p>
3594
3595<hr>
3596<a name="388"><h3>388.&nbsp;Use of complex as a key in associative containers</h3></a><p><b>Section:</b>&nbsp;26.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.cfenv"> [lib.cfenv]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Gabriel Dos Reis&nbsp; <b>Date:</b>&nbsp;8 Nov 2002</p>
3597<p>
3598Practice with std::complex&lt;&gt; and the associative containers
3599occasionally reveals artificial and distracting issues with constructs
3600resembling: std::set&lt;std::complex&lt;double&gt; &gt; s;
3601</p>
3602
3603<p>
3604The main reason for the above to fail is the absence of an approriate
3605definition for std::less&lt;std::complex&lt;T&gt; &gt;. That in turn comes from
3606the definition of the primary template std::less&lt;&gt; in terms of
3607operator&lt;.
3608</p>
3609
3610<p>
3611The usual argument goes as follows: Since there is no ordering over
3612the complex field compatible with field operations it makes little
3613sense to define a function operator&lt; operating on the datatype
3614std::complex&lt;T&gt;.  That is fine. However, that reasoning does not carry
3615over to std::less&lt;T&gt; which is used, among other things, by associative
3616containers as an ordering useful to meet complexity requirements.
3617</p>
3618
3619<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#348">348</a>.</p>
3620
3621<p><b>Proposed resolution:</b></p>
3622<p>Informally: Add a specialization of std::less for std::complex.</p>
3623<p><b>Rationale:</b></p>
3624<p>Discussed in Santa Cruz.  An overwhelming majority of the LWG
3625believes this should not be treated a DR: it's a request for a design
3626change, not a defect in the existing standard.  Most people (10-3)
3627believed that we probably don't want this change, period: as with
3628issue <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.
3629The LWG noted that users who want to put objects into an associative
3630container for which <tt>operator&lt;</tt> isn't defined can simply
3631provide their own comparison function object.</p>
3632<hr>
3633<a name="390"><h3>390.&nbsp;CopyConstructible requirements too strict</h3></a><p><b>Section:</b>&nbsp;20.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.copyconstructible"> [lib.copyconstructible]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Future">Future</a>&nbsp; <b>Submitter:</b>&nbsp;Doug Gregor&nbsp; <b>Date:</b>&nbsp;24 Oct 2002</p>
3634<p>
3635The CopyConstructible requirements in Table 30 state that for an
3636object t of type T (where T is CopyConstructible), the expression &amp;t
3637returns the address of t (with type T*). This requirement is overly
3638strict, in that it disallows types that overload operator&amp; to not
3639return a value of type T*. This occurs, for instance, in the <a href="http://www.boost.org/libs/lambda">Boost.Lambda</a> library, where
3640operator&amp; is overloaded for a Boost.Lambda function object to return
3641another function object.
3642</p>
3643
3644<p>Example:</p>
3645
3646<pre>  std::vector&lt;int&gt; u, v;
3647  int x;
3648  // ...
3649  std::transform(u.begin(), u.end(), std::back_inserter(v), _1 * x);
3650</pre>
3651
3652<p>
3653_1 * x returns an unnamed function object with operator&amp; overloaded to
3654not return T* , therefore rendering the std::transform call ill-formed.
3655However, most standard library implementations will compile this code
3656properly, and the viability of such binder libraries is severely hindered
3657by the unnecessary restriction in the CopyConstructible requirements.
3658</p>
3659
3660<p>
3661For reference, the address of an object can be retrieved without using
3662the address-of operator with the following function template:
3663</p>
3664
3665<pre>  template &lt;typename T&gt; T* addressof(T&amp; v)
3666  {
3667    return reinterpret_cast&lt;T*&gt;(
3668         &amp;const_cast&lt;char&amp;&gt;(reinterpret_cast&lt;const volatile char &amp;&gt;(v)));
3669  }
3670</pre>
3671
3672<p>
3673Note: this relates directly to library issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, which
3674will need to be reexamined if the CopyConstructible requirements
3675change.
3676</p>
3677<p><b>Proposed resolution:</b></p>
3678<p>
3679Remove the last two rows of Table 30, eliminating the requirements
3680that &amp;t and &amp;u return the address of t and u, respectively.
3681</p>
3682<p><b>Rationale:</b></p>
3683<p>This was a deliberate design decision.  Perhaps it should be
3684   reconsidered for C++0x. </p>
3685<hr>
3686<a name="392"><h3>392.&nbsp;'equivalence' for input iterators</h3></a><p><b>Section:</b>&nbsp;24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Corwin Joy&nbsp; <b>Date:</b>&nbsp;11 Dec 2002</p>
3687
3688<p>
3689In section 24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a> table 72 -
3690'Input Iterator Requirements' we have as a postcondition of *a:
3691"If a==b and (a, b) is in the domain of == then *a is equivalent to *b".
3692</p>
3693
3694<p>
3695In section 24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a> it states that
3696"istreambuf_iterator::equal returns true if and only if both iterators
3697are at end-of-stream, or neither is at end-of-stream, <i>regardless of
3698what streambuf object they use</i>."  (My emphasis).
3699</p>
3700
3701<p>
3702The defect is that either 'equivalent' needs to be more precisely
3703defined or the conditions for equality in 24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a>
3704are incorrect. (Or both).
3705</p>
3706
3707<p>Consider the following example:</p>
3708<pre>   #include &lt;iostream&gt;
3709   #include &lt;fstream&gt;
3710   #include &lt;iterator&gt;
3711   using namespace std;
3712
3713   int main() {
3714    ifstream file1("file1.txt"), file2("file2.txt");
3715    istreambuf_iterator&lt;char&gt; f1(file1), f2(file2);
3716    cout &lt;&lt; "f1 == f2 : " &lt;&lt; boolalpha &lt;&lt; (f1 == f2) &lt;&lt; endl;
3717    cout &lt;&lt; "f1 = " &lt;&lt; *f1 &lt;&lt; endl;
3718    cout &lt;&lt; "f2 = " &lt;&lt; *f2 &lt;&lt; endl;
3719    return 0;
3720   }
3721</pre>
3722
3723<p>Now assuming that neither f1 or f2 are at the end-of-stream then
3724f1 == f2 by 24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a>.</p>
3725
3726<p>However, it is unlikely that *f1 will give the same value as *f2 except
3727by accident.</p>
3728
3729<p>So what does *f1 'equivalent' to *f2 mean?  I think the standard should
3730be clearer on this point, or at least be explicit that this does not
3731mean that *f1 and *f2 are required to have the same value in the case
3732of input iterators.</p>
3733<p><b>Proposed resolution:</b></p>
3734<p><b>Rationale:</b></p>
3735<p>The two iterators aer not in the domain of ==</p>
3736<hr>
3737<a name="399"><h3>399.&nbsp;volations of unformatted input function requirements</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;5 Jan 2003</p>
3738    <p>
3739The Effects clauses for the two functions below violate the
3740general requirements on unformatted input functions outlined
3741in 27.6.1.3: they do not begin by constructing a sentry object.
3742Instead, they begin by calling widen ('\n'), which may throw
3743an exception. The exception is then allowed to propagate from
3744the unformatted input function irrespective of the setting of
3745exceptions().
3746    </p>
3747    <p>
3748Note that in light of 27.6.1.1, p3 and p4, the fact that the
3749functions allow exceptions thrown from widen() to propagate
3750may not strictly speaking be a defect (but the fact that the
3751functions do not start by constructing a sentry object still
3752is). However, since an exception thrown from ctype&lt;charT&gt;
3753::widen() during any other input operation (say, from within
3754a call to num_get&lt;charT&gt;::get()) will be caught and cause
3755badbit to be set, these two functions should not be treated
3756differently for the sake of consistency.
3757    </p>
3758  <p><b>Proposed resolution:</b></p>
3759<p><b>Rationale:</b></p>
3760<p>
3761Not a defect.  The standard is consistent, and the behavior required
3762by the standard is unambiguous.  Yes, it's theoretically possible for
3763widen to throw.  (Not that this will happen for the default ctype
3764facet or for most real-world replacement ctype facets.)  Users who
3765define ctype facets that can throw, and who care about this behavior,
3766can use alternative signatures that don't call widen.
3767</p>
3768<hr>
3769<a name="429"><h3>429.&nbsp;typo in basic_ios::clear(iostate)</h3></a><p><b>Section:</b>&nbsp;27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2003</p>
3770        <p>
3771
3772The Effects clause in 27.4.4.3, p5 describing the effects of a call to
3773the ios_base member function clear(iostate state) says that the function
3774only throws if the respective bits are already set prior to the function
3775call. That's obviously not the intent. If it was, a call to clear(badbit)
3776on an object for which (rdstate() == goodbit &amp;&amp; exceptions() == badbit)
3777holds would not result in an exception being thrown.
3778
3779        </p>
3780    <p><b>Proposed resolution:</b></p>
3781        <p>
3782
3783The text ought to be changed from
3784<br>
3785
3786"If (rdstate() &amp; exceptions()) == 0, returns. ..."
3787<br>
3788
3789to
3790<br>
3791
3792"If (state &amp; exceptions()) == 0, returns. ..."
3793        </p>
3794<p><b>Rationale:</b></p>
3795<p>This is a duplicate of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#412">412</a>.</p>
3796<hr>
3797<a name="433"><h3>433.&nbsp;Contradiction in specification of unexpected()</h3></a><p><b>Section:</b>&nbsp;18.7.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.unexpected"> [lib.unexpected]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Vyatcheslav Sysoltsev&nbsp; <b>Date:</b>&nbsp;29 Sep 2003</p>
3798<p>
3799Clause 15.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/except.html#except.unexpected"> [except.unexpected]</a> paragraph 1 says that "void unexpected();
3800is called (18.7.2) immediately after completing the stack unwinding
3801for the former function", but 18.7.2.4 (Effects) says that "void
3802unexpected(); . . . Calls the unexpected_handler function in effect
3803immediately after evaluating the throwexpression (18.7.2.2),".  Isn't
3804here a contradiction: 15.5.2 requires stack have been unwound when in
3805void unexpected() and therefore in unexpected_handler but 18.7.2.4
3806claims that unexpected_handler is called "in effect immediately" after
3807evaluation of throw expression is finished, so there is no space left
3808for stack to be unwound therefore?  I think the phrase "in effect
3809immediately" should be removed from the standard because it brings
3810ambiguity in understanding.
3811</p>
3812<p><b>Proposed resolution:</b></p>
3813<p><b>Rationale:</b></p>
3814<p>There is no contradiction.  The phrase "in effect immediately" is
3815  just to clarify which handler is to be called.</p>
3816<hr>
3817<a name="437"><h3>437.&nbsp;Formatted output of function pointers is confusing</h3></a><p><b>Section:</b>&nbsp;27.6.2.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.arithmetic"> [lib.ostream.inserters.arithmetic]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Ivan Godard&nbsp; <b>Date:</b>&nbsp;24 Oct 2003</p>
3818<p>
3819Given:
3820</p>
3821<pre>void f(int) {}
3822void(*g)(int) = f;
3823cout &lt;&lt; g;
3824</pre>
3825
3826<p>
3827(with the expected #include and usings), the value printed is a rather
3828surprising "true". Rather useless too.
3829</p>
3830
3831<p>The standard defines:</p>
3832
3833<pre>ostream&amp; operator&lt;&lt;(ostream&amp;, void*);</pre>
3834
3835<p>which picks up all data pointers and prints their hex value, but does
3836not pick up function pointers because there is no default conversion
3837from function pointer to void*. Absent that, we fall back to legacy
3838conversions from C and the function pointer is converted to bool.
3839</p>
3840
3841<p>There should be an analogous inserter that prints the address of a
3842  function pointer.</p>
3843<p><b>Proposed resolution:</b></p>
3844<p><b>Rationale:</b></p>
3845<p>This is indeed a wart, but there is no good way to solve it.  C
3846  doesn't provide a portable way of outputting the address of a
3847  function point either.</p>
3848<hr>
3849<a name="439"><h3>439.&nbsp;Should facets be copyable?</h3></a><p><b>Section:</b>&nbsp;22.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.categories"> [lib.locale.categories]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;2 Nov 2003</p>
3850<p>The following facets classes have no copy constructors described in
3851  the standard, which, according to the standard, means that they are
3852  supposed to use the compiler-generated defaults.  Default copy
3853  behavior is probably inappropriate.  We should either make these
3854  classes uncopyable or else specify exactly what their constructors do.</p>
3855
3856<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#421">421</a>.</p>
3857
3858<pre>        ctype_base
3859        ctype
3860        ctype_byname
3861        ctype&lt;char&gt;
3862        ctype_byname&lt;char&gt;
3863        codecvt_base
3864        codecvt
3865        codecvt_byname
3866        num_get
3867        num_put
3868        numpunct
3869        numpunct_byname
3870        collate
3871        collate_byname
3872        time_base
3873        time_get
3874        time_get_byname
3875        time_put
3876        time_put_byname
3877        money_get
3878        money_put
3879        money_base
3880        moneypunct
3881        moneypunct_byname
3882        messages_base
3883        messages
3884        messages_byname
3885</pre>
3886
3887<p><b>Proposed resolution:</b></p>
3888<p><b>Rationale:</b></p>
3889<p>The copy constructor in the base class is private.</p>
3890<hr>
3891<a name="440"></a><h3><a name="440">440.&nbsp;Should std::complex use unqualified transcendentals?</a></h3><p><b>Section:</b>&nbsp;26.3.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.transcendentals"> [lib.complex.transcendentals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;5 Nov 2003</p>
3892<p>
3893Operations like <tt>pow</tt> and <tt>exp</tt> on
3894<tt>complex&lt;T&gt;</tt> are typically implemented in terms of
3895operations like <tt>sin</tt> and <tt>cos</tt> on <tt>T</tt>.
3896Should implementations write this as <tt>std::sin</tt>, or as plain
3897unqualified <tt>sin</tt>?
3898</p>
3899
3900<p>The issue, of course, is whether we want to use
3901argument-dependent lookup in the case where <tt>T</tt> is a
3902user-defined type.  This is similar to the issue of valarray
3903transcendentals, as discussed in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>.</p>
3904
3905<p>This issue differs from valarray transcendentals in two important
3906ways.  First, "the effect of instantiating the template
3907<tt>complex</tt> for types other than float, double or long double is
3908unspecified." (26.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.synopsis"> [lib.complex.synopsis]</a>) Second, the standard does not
3909dictate implementation, so there is no guarantee that a particular
3910real math function is used in the implementation of a particular
3911complex function.</p>
3912
3913<p><b>Proposed resolution:</b></p>
3914<p><b>Rationale:</b></p>
3915<p>If you instantiate std::complex for user-defined types, all bets
3916are off.</p>
3917<hr>
3918<a name="447"><h3>447.&nbsp;Wrong template argument for time facets</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Pete Becker&nbsp; <b>Date:</b>&nbsp;26 Dec 2003</p>
3919<p>
392022.1.1.1.1/4, table 52, "Required Instantiations", lists, among others:
3921</p>
3922<pre>    time_get&lt;char,InputIterator&gt;
3923    time_get_byname&lt;char,InputIterator&gt;
3924    time_get&lt;wchar_t,OutputIterator&gt;
3925    time_get_byname&lt;wchar_t,OutputIterator&gt;
3926</pre>
3927
3928<p>
3929The second argument to the last two should be InputIterator, not
3930OutputIterator.
3931</p>
3932<p><b>Proposed resolution:</b></p>
3933<p>
3934Change the second template argument to InputIterator.
3935</p>
3936<p><b>Rationale:</b></p>
3937Duplicate of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#327">327</a>
3938<hr>
3939<a name="450"><h3>450.&nbsp;set::find is inconsistent with associative container requirements</h3></a><p><b>Section:</b>&nbsp;23.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.set"> [lib.set]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Bill Plauger&nbsp; <b>Date:</b>&nbsp;30 Jan 2004</p>
3940<p>map/multimap have:</p>
3941
3942<pre>	iterator find(const key_type&amp; x) const;
3943	const_iterator find(const key_type&amp; x) const;
3944</pre>
3945
3946<p>
3947which is consistent with the table of associative container requirements.
3948But set/multiset have:
3949</p>
3950<pre>	iterator find(const key_type&amp;) const;
3951</pre>
3952
3953<p>
3954set/multiset should look like map/multimap, and honor the requirements
3955table, in this regard.
3956</p>
3957<p><b>Proposed resolution:</b></p>
3958<p><b>Rationale:</b></p>
3959<p>Duplicate of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#214">214</a>.</p>
3960<hr>
3961<a name="451"><h3>451.&nbsp;Associative erase should return an iterator</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>, 23.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative"> [lib.associative]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Bill Plauger&nbsp; <b>Date:</b>&nbsp;30 Jan 2004</p>
3962<p>map/multimap/set/multiset have:</p>
3963<pre>	void erase(iterator);
3964	void erase(iterator, iterator);
3965</pre>
3966
3967<p>But there's no good reason why these can't return an iterator, as for
3968vector/deque/list:</p>
3969<pre>	iterator erase(iterator);
3970	iterator erase(iterator, iterator);
3971</pre>
3972
3973<p><b>Proposed resolution:</b></p>
3974<p>
3975Informally: The table of associative container requirements, and the
3976relevant template classes, should return an iterator designating the
3977first element beyond the erased subrange.
3978</p>
3979<p><b>Rationale:</b></p>
3980<p>Duplicate of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a></p>
3981<hr>
3982<a name="452"><h3>452.&nbsp; locale::combine should be permitted to generate a named locale</h3></a><p><b>Section:</b>&nbsp;22.1.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.members"> [lib.locale.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Bill Plauger&nbsp; <b>Date:</b>&nbsp;30 Jan 2004</p>
3983<pre>template&lt;class Facet&gt;
3984	locale::combine(const locale&amp;) const;
3985</pre>
3986<p>
3987is obliged to create a locale that has no name. This is overspecification
3988and overkill. The resulting locale should follow the usual rules -- it
3989has a name if the locale argument has a name and Facet is one of the
3990standard facets.
3991</p>
3992
3993<p><i>[
3994 Sydney and post-Sydney (see c++std-lib-13439, c++std-lib-13440,
3995 c++std-lib-13443): agreed that it's overkill to say that the locale
3996 is obligated to be nameless.  However, we also can't require it to
3997 have a name.  At the moment, locale names are based on categories
3998 and not on individual facets.  If a locale contains two different
3999 facets of different names from the same category, then this would
4000 not fit into existing naming schemes.  We need to give
4001 implementations more freedom.  Bill will provide wording.
4002]</i></p>
4003
4004<p><b>Proposed resolution:</b></p>
4005<p><b>Rationale:</b></p>
4006<p>After further discussion the LWG decided to close this as NAD.
4007  The fundamental problem is that names right now are per-category,
4008  not per-facet.  The <tt>combine</tt> member function works at the
4009  wrong level of granularity.</p>
4010<hr>
4011<a name="472"><h3>472.&nbsp;Missing "Returns" clause in std::equal_range</h3></a><p><b>Section:</b>&nbsp;25.3.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.equal.range"> [lib.equal.range]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Prateek R Karandikar&nbsp; <b>Date:</b>&nbsp;29 Feb 1900</p>
4012<p>
4013There is no "Returns:" clause for std::equal_range, which returns non-void.
4014</p>
4015<p><b>Proposed resolution:</b></p>
4016<p><b>Rationale:</b></p>
4017<p>Fixed as part of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a>.</p>
4018<hr>
4019<a name="476"><h3>476.&nbsp;Forward Iterator implied mutability</h3></a><p><b>Section:</b>&nbsp;24.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.forward.iterators"> [lib.forward.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;9 Jul 2004</p>
4020
4021<p>24.1/3 says:</p>
4022<blockquote>
4023  Forward iterators satisfy all the requirements of the input and
4024  output iterators and can be used whenever either kind is specified
4025</blockquote>
4026
4027<p>
4028The problem is that satisfying the requirements of output iterator
4029means that you can always assign *something* into the result of
4030dereferencing it.  That makes almost all non-mutable forward
4031iterators non-conforming.  I think we need to sever the refinement
4032relationship between forward iterator and output iterator.
4033</p>
4034
4035<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>
4036
4037<p><b>Proposed resolution:</b></p>
4038<p><b>Rationale:</b></p>
4039<p>Yes, 24.1/3 does say that. But it's introductory material. The
4040precise specification is in 24.1.3, and the requrements table there is
4041right.  We don't need to fine-tune introductory wording.  (Especially
4042since this wording is likely to be changed as part of the iterator
4043overhaul.)</p>
4044<hr>
4045<a name="477"><h3>477.&nbsp;Operator-&gt; for const forward iterators</h3></a><p><b>Section:</b>&nbsp;24.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.forward.iterators"> [lib.forward.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;11 Jul 2004</p>
4046<p>
4047The Forward Iterator requirements table contains the following:
4048</p>
4049<pre> expression  return type         operational  precondition
4050                                  semantics
4051  ==========  ==================  ===========  ==========================
4052  a-&gt;m        U&amp; if X is mutable, (*a).m       pre: (*a).m is well-defined.
4053              otherwise const U&amp;
4054
4055  r-&gt;m        U&amp;                  (*r).m       pre: (*r).m is well-defined.
4056</pre>
4057
4058<p>
4059The first line is exactly right.  The second line is wrong.  Basically
4060it implies that the const-ness of the iterator affects the const-ness
4061of referenced members.  But Paragraph 11 of [lib.iterator.requirements] says:
4062</p>
4063
4064<blockquote>
4065   In the following sections, a and b denote values of type const X, n
4066   denotes a value of the difference type Distance, u, tmp, and m
4067   denote identifiers, r denotes a value of X&amp;, t denotes a value of
4068   value type T, o denotes a value of some type that is writable to
4069   the output iterator.
4070</blockquote>
4071
4072<p>AFAICT if we need the second line at all, it should read the same
4073as the first line.</p>
4074
4075<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a></p>
4076<p><b>Proposed resolution:</b></p>
4077<p><b>Rationale:</b></p>
4078<p>The LWG agrees that this is a real problem.  Marked as a DUP
4079  because the LWG chose to adopt the solution proposed in
4080  <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>.
4081</p>
4082<hr>
4083<a name="480"><h3>480.&nbsp;unary_function and binary_function should have protected nonvirtual destructors</h3></a><p><b>Section:</b>&nbsp;20.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple.tuple"> [lib.tuple.tuple]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Joe Gottman&nbsp; <b>Date:</b>&nbsp;19 Aug 2004</p>
4084<p>The classes std::unary_function and std::binary_function are both
4085designed to be inherited from but contain no virtual functions.  This
4086makes it too easy for a novice programmer to write code like
4087binary_function&lt;int, int, int&gt; *p = new plus&lt;int&gt;; delete p;</p>
4088
4089<p>There are two common ways to prevent this source of undefined
4090behavior: give the base class a public virtual destructor, or give it
4091a protected nonvirtual destructor.  Since unary_function and
4092binary_function have no other virtual functions, (note in particular
4093the absence of an operator()() ), it would cost too much to give them
4094public virtual destructors.  Therefore, they should be given protected
4095nonvirtual destructors.</p>
4096<p><b>Proposed resolution:</b></p>
4097<p>Change Paragraph 20.3.1 of the Standard from</p>
4098<pre>    template &lt;class Arg, class Result&gt;
4099    struct unary_function {
4100        typedef Arg argument_type;
4101        typedef Result result_type;
4102    };
4103
4104    template &lt;class Arg1, class Arg2, class Result&gt;
4105    struct binary_function {
4106        typedef Arg1 first_argument_type;
4107        typedef Arg2 second_argument_type;
4108        typedef Result result_type;
4109    };
4110</pre>
4111
4112<p>to</p>
4113<pre>    template &lt;class Arg, class Result&gt;
4114        struct unary_function {
4115        typedef Arg argument_type;
4116        typedef Result result_type;
4117    protected:
4118        ~unary_function() {}
4119    };
4120
4121    template &lt;class Arg1, class Arg2, class Result&gt;
4122    struct binary_function {
4123        typedef Arg1 first_argument_type;
4124        typedef Arg2 second_argument_type;
4125        typedef Result result_type;
4126    protected:
4127        ~binary_function() {}
4128    };
4129</pre>
4130<p><b>Rationale:</b></p>
4131<p>The LWG doesn't believe the existing definition causes anybody any
4132  concrete harm.</p>
4133<hr>
4134<a name="481"><h3>481.&nbsp;unique's effects on the range [result, last)</h3></a><p><b>Section:</b>&nbsp;25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;30 Aug 2004</p>
4135<p>
4136The standard says that unique(first, last) "eliminates all but the
4137first element from every consecutive group of equal elements" in
4138[first, last) and returns "the end of the resulting range".  So a
4139postcondition is that [first, result) is the same as the old [first,
4140last) except that duplicates have been eliminated.
4141</p>
4142
4143<p>What postconditions are there on the range [result, last)?  One
4144  might argue that the standard says nothing about those values, so
4145  they can be anything.  One might also argue that the standard
4146  doesn't permit those values to be changed, so they must not be.
4147  Should the standard say something explicit one way or the other?</p>
4148
4149<p><b>Proposed resolution:</b></p>
4150<p>
4151</p>
4152<p><b>Rationale:</b></p>
4153<p>We don't want to make many guarantees about what's in [result,
4154end). Maybe we aren't being quite explicit enough about not being
4155explicit, but it's hard to think that's a major problem.</p>
4156<hr>
4157<a name="483"><h3>483.&nbsp;Heterogeneous equality and EqualityComparable</h3></a><p><b>Section:</b>&nbsp;25.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.nonmodifying"> [lib.alg.nonmodifying]</a>, 25.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.modifying.operations"> [lib.alg.modifying.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Peter Dimov&nbsp; <b>Date:</b>&nbsp;20 Sep 2004</p>
4158<p>c++std-lib-14262</p>
4159
4160<p>[lib.alg.find] requires T to be EqualityComparable:</p>
4161
4162<pre>template &lt;class InputIterator, class T&gt;
4163   InputIterator find(InputIterator first, InputIterator last,
4164                      const T&amp; value);
4165</pre>
4166
4167<p>
4168However the condition being tested, as specified in the Effects
4169clause, is actually *i == value, where i is an InputIterator.
4170</p>
4171
4172<p>
4173The two clauses are in agreement only if the type of *i is T, but this
4174isn't necessarily the case. *i may have a heterogeneous comparison
4175operator that takes a T, or a T may be convertible to the type of *i.
4176</p>
4177
4178<p>Further discussion (c++std-lib-14264): this problem affects a
4179  number of algorithsm in clause 25, not just <tt>find</tt>.  We
4180  should try to resolve this problem everywhere it appears.</p>
4181<p><b>Proposed resolution:</b></p>
4182
4183<p>[lib.alg.find]:</p>
4184<blockquote>
4185   Remove [lib.alg.find]/1.
4186</blockquote>
4187
4188<p>[lib.alg.count]:</p>
4189<blockquote>
4190   Remove [lib.alg.count]/1.
4191</blockquote>
4192
4193<p>[lib.alg.search]:</p>
4194<blockquote>
4195   Remove "Type T is EqualityComparable (20.1.1), " from [lib.alg.search]/4.
4196</blockquote>
4197
4198<p>[lib.alg.replace]:</p>
4199
4200<blockquote>
4201   <p>
4202   Remove [lib.alg.replace]/1.
4203   Replace [lb.alg.replace]/2 with:
4204   </p>
4205
4206       <blockquote>
4207       For every iterator i in the range [first, last) for which *i == value
4208       or pred(*i) holds perform *i = new_value.
4209       </blockquote>
4210
4211   <p>
4212   Remove the first sentence of /4.
4213   Replace the beginning of /5 with:
4214   </p>
4215
4216       <blockquote>
4217       For every iterator i in the range [result, result + (last -
4218       first)), assign to *i either...
4219       </blockquote>
4220
4221   <p>(Note the defect here, current text says assign to i, not *i).</p>
4222</blockquote>
4223
4224<p>[lib.alg.fill]:</p>
4225
4226<blockquote>
4227   <p>
4228   Remove "Type T is Assignable (23.1), " from /1.
4229   Replace /2 with:
4230   </p>
4231
4232       <blockquote>
4233       For every iterator i in the range [first, last) or [first, first + n),
4234       perform *i = value.
4235       </blockquote>
4236</blockquote>
4237
4238<p>[lib.alg.remove]:</p>
4239<blockquote>
4240   Remove /1.
4241   Remove the first sentence of /6.
4242</blockquote>
4243
4244<p><b>Rationale:</b></p>
4245<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>
4246<hr>
4247<a name="486"><h3>486.&nbsp;min/max CopyConstructible requirement is too strict</h3></a><p><b>Section:</b>&nbsp;25.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;13 Oct 2004</p>
4248<p>A straightforward implementation of these algorithms does not need to
4249copy T.</p>
4250<p><b>Proposed resolution:</b></p>
4251<p>drop the the words "and CopyConstructible" from paragraphs 1 and 4</p>
4252<p><b>Rationale:</b></p>
4253<p>Dup of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#281">281</a>.</p>
4254<hr>
4255<a name="487"><h3>487.&nbsp;Allocator::construct is too limiting</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Dhruv Matani&nbsp; <b>Date:</b>&nbsp;17 Oct 2004</p>
4256<p>
4257The standard's version of allocator::construct(pointer,
4258const_reference) severely limits what you can construct using this
4259function.  Say you can construct a socket from a file descriptor. Now,
4260using this syntax, I first have to manually construct a socket from
4261the fd, and then pass the constructed socket to the construct()
4262function so it will just to an uninitialized copy of the socket I
4263manually constructed. Now it may not always be possible to copy
4264construct a socket eh! So, I feel that the changes should go in the
4265allocator::construct(), making it:
4266</p>
4267<pre>    template&lt;typename T&gt;
4268    struct allocator{
4269      template&lt;typename T1&gt;
4270      void construct(pointer T1 const&amp; rt1);
4271    };
4272</pre>
4273
4274<p>
4275Now, the ctor of the class T which matches the one that takes a T1 can
4276be called! Doesn't that sound great?
4277</p>
4278<p><b>Proposed resolution:</b></p>
4279<p><b>Rationale:</b></p>
4280<p>NAD. STL uses copying all the time, and making it possible for
4281  allocators to construct noncopyable objects is useless in the
4282  absence of corresponding container changes. We might consider this
4283  as part of a larger redesign of STL.</p>
4284<hr>
4285<a name="489"><h3>489.&nbsp;std::remove / std::remove_if wrongly specified</h3></a><p><b>Section:</b>&nbsp;25.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.remove"> [lib.alg.remove]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Thomas Mang&nbsp; <b>Date:</b>&nbsp;12 Dec 2004</p>
4286<p>In Section 25.2.7 [lib.alg.remove], paragraphs 1 to 5 describe the
4287behavior of the mutating sequence operations std::remove and
4288std::remove_if. However, the wording does not reflect the intended
4289behavior [Note: See definition of intended behavior below] of these
4290algorithms, as it is known to the C++ community [1].
4291</p>
4292
4293
4294
4295<p>1) Analysis of current wording:</p>
4296
4297
4298<p>25.2.7 [lib.alg.remove], paragraph 2:</p>
4299
4300<p>Current wording says:
4301"Effects: Eliminates all the elements referred to by iterator i in the
4302range [first, last) for which the following corresponding conditions
4303hold: *i == value, pred(*i) != false."</p>
4304
4305<p>
4306This sentences expresses specifically that all elements denoted by the
4307(original) range [first, last) for which the corresponding condition
4308hold will be eliminated. Since there is no formal definition of the term
4309"eliminate" provided, the meaning of "eliminate" in everyday language
4310implies that as postcondition, no element in the range denoted by
4311[first, last) will hold the corresponding condition on reiteration over
4312the range [first, last).
4313</p>
4314
4315<p>
4316However, this is neither the intent [Note: See definition of intended
4317behavior below] nor a general possible approach. It can be easily proven
4318that if all elements of the original range[first, last) will hold the
4319condition, it is not possible to substitute them by an element for which
4320the condition will not hold.
4321</p>
4322
4323
4324<p>25.2.7 [lib.alg.remove], paragraph 3:</p>
4325
4326<p>
4327Current wording says:
4328"Returns: The end of the resulting range."
4329</p>
4330
4331<p>
4332The resulting range is not specified. In combination with 25.2.7
4333[lib.alg.remove], paragraph 2, the only reasonable interpretation of
4334this so-called resulting range is the range [first,last) - thus
4335returning always the ForwardIterator 'last' parameter.
4336</p>
4337
4338
4339<p>
434025.2.7 [lib.alg.remove], paragraph 4:
4341</p>
4342
4343<p>
4344Current wording says:
4345"Notes: Stable: the relative order of the elements that are not removed
4346is the same as their relative order in the original range"
4347</p>
4348
4349<p>
4350This sentences makes use of the term "removed", which is neither
4351specified, nor used in a previous paragraph (which uses the term
4352"eliminate"), nor unamgiuously separated from the name of the algorithm.
4353</p>
4354
4355
4356<p>2) Description of intended behavior:</p>
4357
4358<p>
4359For the rest of this Defect Report, it is assumed that the intended
4360behavior was that all elements of the range [first, last) which do not
4361hold the condition *i == value (std::remove) or  pred(*i) != false
4362(std::remove_if)], call them s-elements [Note: s...stay], will be placed
4363into a contiguous subrange of [first, last), denoted by the iterators
4364[first, return value). The number of elements in the resulting range
4365[first, return value) shall be equal to the number of s-elements in the
4366original range [first, last). The relative order of the elements in the
4367resulting subrange[first, return value) shall be the same as the
4368relative order of the corresponding elements in the original range. It
4369is undefined whether any elements in the resulting subrange [return
4370value, last) will hold the corresponding condition, or not.
4371</p>
4372
4373<p>
4374All implementations known to the author of this Defect Report comply
4375with this intent. Since the intent  of the behavior (contrary to the
4376current wording) is also described in various utility references serving
4377the C++ community [1], it is not expected that fixing the paragraphs
4378will influence current code - unless the code relies on the behavior as
4379it is described by current wording and the implementation indeed
4380reflects the current wording, and not the intent.
4381</p>
4382
4383
4384
4385<p>3) Proposed fixes:</p>
4386
4387
4388<p>Change 25.2.7 [lib.alg.remove], paragraph 2 to:</p>
4389
4390<p>
4391"Effect: Places all the elements referred to by iterator i in the range
4392[first, last) for which the following corresponding conditions hold :
4393!(*i == value), pred(*i) == false into the subrange [first, k) of the
4394original range, where k shall denote a value of type ForwardIterator. It
4395is undefined whether any elements in the resulting subrange [k, last)
4396will hold the corresponding condition, or not."
4397</p>
4398
4399<p>Comments to the new wording:</p>
4400
4401<p>
4402a) "Places" has no special meaning, and the everyday language meaning
4403should fit.
4404b) The corresponding conditions were negated compared to the current
4405wording, becaue the new wording requires it.
4406c) The wording "of the original range" might be redundant, since any
4407subrange starting at 'first' and containing no more elements than the
4408original range is implicitly a subrange of the original range [first,
4409last).
4410d) The iterator k was introduced instead of "return value" in order to
4411avoid a cyclic dependency on 25.2.7/3. The wording ", where k shall
4412denote a value of type ForwardIterator" might be redundant, because it
4413follows implicitly by 25.2.7/3.
4414e) "Places" does, in the author's opinion, explicitly forbid duplicating
4415any element holding the corresponding condition in the original range
4416[first, last) within the resulting range [first, k). If there is doubt
4417this term might be not unambiguous regarding this, it is suggested that
4418k is specified more closely by the following wording: "k shall denote a
4419value of type ForwardIterator [Note: see d)] so that k - first is equal
4420to the number of elements in the original range [first, last) for which
4421the corresponding condition did hold". This could also be expressed as a
4422separate paragraph "Postcondition:"
4423f) The senctence "It is undefined whether any elements in the resulting
4424subrange [k, last) will hold the corresponding condition, or not." was
4425added consciously so the term "Places" does not imply if the original
4426range [first, last) contains n elements holding the corresponding
4427condition, the identical range[first, last) will also contain exactly n
4428elements holding the corresponding condition after application of the
4429algorithm.
4430</p>
4431
4432<p>
4433Change 25.2.7 [lib.alg.remove], paragraph 3 to:
4434
4435"Returns: The iterator k."
4436</p>
4437
4438<p>
4439Change 25.2.7 [lib.alg.remove], paragraph 4 to:
4440
4441"Notes: Stable: the relative order of the elements that are placed into
4442the subrange [first, return value) shall be the same as their relative
4443order was in the original range [first, last) prior to application of
4444the algorithm."
4445</p>
4446
4447<p>
4448Comments to the new wording:
4449</p>
4450
4451<p>
4452a) the wording "was ...  prior to application of the algorithm" is used
4453to explicitly distinguish the original range not only by means of
4454iterators, but also by a 'chronological' factor from the resulting range
4455[first, return value). It might be redundant.
4456</p>
4457
4458<p>
4459[1]:
4460The wording of these references is not always unambiguous, and provided
4461examples partially contradict verbal description of the algorithms,
4462because the verbal description resembles the problematic wording of
4463ISO/IEC 14882:2003.
4464</p>
4465<p><b>Proposed resolution:</b></p>
4466<p><b>Rationale:</b></p>
4467<p>The LWG believes that the standard is sufficiently clear, and that
4468  there is no evidence of any real-world confusion about this point.</p>
4469<hr>
4470<a name="490"><h3>490.&nbsp;std::unique wrongly specified</h3></a><p><b>Section:</b>&nbsp;25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Thomas Mang&nbsp; <b>Date:</b>&nbsp;12 Dec 2004</p>
4471<p>In Section 25.2.8 [lib.alg.unique], paragraphs 1 to 3 describe the
4472behavior of the mutating sequence operation std::unique. However, the
4473wording does not reflect the intended behavior [Note: See definition of
4474intended behavior below] of these algorithms, as it is known to the C++
4475community [1].</p>
4476
4477
4478
4479<p>1) Analysis of current wording:</p>
4480
4481
4482<p>25.2.8 [lib.alg.unique], paragraph 1:</p>
4483
4484<p>
4485Current wording says:
4486"Effects: Eliminates all but the first element from every consecutive
4487group of equal elements referred to by the iterator i in the range
4488[first, last) for which the following corresponding conditions hold: *i
4489== *(i - 1) or pred(*i, *(i -1)) != false"
4490</p>
4491
4492<p>
4493This sentences expresses specifically that all elements denoted by the
4494(original) range [first, last) which are not but the first element from
4495a consecutive group of equal elements (where equality is defined as *i
4496== *(i - 1) or pred(*i, *(i - 1)) ! = false) [Note: See DR 202], call
4497them r-elements [Note: r...remove], will be eliminated. Since there is
4498no formal definition of the term "eliminate" provided, it is undefined
4499how this "elimination" takes place. But the meaning of "eliminate" in
4500everyday language seems to disallow explicitly that after application of
4501the algorithm, any r-element will remain at any position of the range
4502[first, last) [2].
4503</p>
4504
4505<p>
4506Another defect in the current wording concerns the iterators used to
4507compare two elements for equality: The current wording contains the
4508expression "(i - 1)", which is not covered by 25/9 [Note: See DR
4509submitted by Thomas Mang regarding invalid iterator arithmetic
4510expressions].
4511</p>
4512
4513
4514<p>
451525.2.8 [lib.alg.unique], paragraph 2:
4516</p>
4517<p>Current wording says:
4518"Returns: The end of the resulting range."</p>
4519
4520<p>
4521The resulting range is not specified. In combination with 25.2.8
4522[lib.alg.unique], paragraph 1, one reasonable interpretation (in the
4523author's opinion even the only possible interpretation) of this
4524so-called resulting range is the range [first, last) - thus returning
4525always the ForwardIterator 'last' parameter.
4526</p>
4527
4528<p>2) Description of intended behavior:</p>
4529
4530<p>
4531For the rest of this Defect Report, it is assumed that the intended
4532behavior was that all elements denoted by the original range [first,
4533last) which are the first element from a consecutive group of elements
4534for which the corresponding conditions: *(i-1) == *i (for the version of
4535unique without a predicate argument) or pred(*(i-1), *i) ! = false (for
4536the version of unique with a predicate argument) [Note: If such a group
4537of elements consists of only a single element, this is also considered
4538the first element] [Note: See resolutions of DR 202], call them
4539s-elements [Note: s...stay], will be placed into a contiguous subrange
4540of [first, last), denoted by the iterators [first, return value). The
4541number of elements in the resulting range [first, return value) shall be
4542equal to the number of s-elements in the original range [first, last).
4543Invalid iterator arithmetic expressions are expected to be resolved as
4544proposed in DR submitted by Thomas Mang regarding invalid iterator
4545arithmetic expressions. It is also assumed by the author that the
4546relative order of the elements in the resulting subrange [first, return
4547value) shall be the same as the relative order of the corresponding
4548elements (the s-elements) in the original range [Note: If this was not
4549intended behavior, the additional proposed paragraph about stable order
4550will certainly become obsolete].
4551Furthermore, the resolutions of DR 202 are partially considered.
4552</p>
4553
4554<p>
4555All implementations known to the author of this Defect Report comply
4556with this intent [Note: Except possible effects of DR 202]. Since this
4557intent of the behavior (contrary to the current wording) is also
4558described in various utility references serving the C++ community [1],
4559it is not expected that fixing the paragraphs will influence current
4560code [Note: Except possible effects of DR 202] - unless the code relies
4561on the behavior as it is described by current wording and the
4562implementation indeed reflects the current wording, and not the intent.
4563</p>
4564
4565
4566
4567<p>3) Proposed fixes:</p>
4568
4569<p>
4570Change 25.2.8 [lib.alg.unique], paragraph 1 to:
4571</p>
4572
4573<p>
4574"Effect: Places the first element from every consecutive group of
4575elements, referred to by the iterator i in the range [first, last), for
4576which the following conditions hold: *(i-1) == *i (for the version of
4577unique without a predicate argument) or pred(*(i -1), *i) != false (for
4578the version of unique with a predicate argument), into the subrange
4579[first, k) of the original range, where k shall denote a value of type
4580ForwardIterator."
4581</p>
4582
4583<p>Comments to the new wording:</p>
4584
4585<p>
4586a) The new wording was influenced by the resolutions of DR 202. If DR
4587202 is resolved in another way, the proposed wording need also
4588additional review.
4589b) "Places" has no special meaning, and the everyday language meaning
4590should fit.
4591c) The expression "(i - 1)" was left, but is expected that DR submitted
4592by Thomas Mang regarding invalid iterator arithmetic expressions will
4593take this into account.
4594d) The wording "(for the version of unique without a predicate
4595argument)" and "(for the version of unique with a predicate argument)"
4596was added consciously for clarity and is in resemblence with current
459723.2.2.4 [lib.list.ops], paragraph 19. It might be considered redundant.
4598e) The wording "of the original range" might be redundant, since any
4599subrange starting at first and containing no more elements than the
4600original range is implicitly a subrange of the original range [first,
4601last).
4602f) The iterator k was introduced instead of "return value" in order to
4603avoid a cyclic dependency on 25.2.8 [lib.alg.unique], paragraph 2. The
4604wording ", where k shall denote a value of type ForwardIterator" might
4605be redundant, because it follows implicitly by 25.2.8 [lib.alg.unique],
4606paragraph 2.
4607g) "Places" does, in the author's opinion, explicitly forbid duplicating
4608any s-element in the original range [first, last) within the resulting
4609range [first, k). If there is doubt this term might be not unambiguous
4610regarding this, it is suggested that k is specified more closely by the
4611following wording: "k shall denote a value of type ForwardIterator
4612[Note: See f)] so that k - first is equal to the number of elements in
4613the original range [first, last) being the first element from every
4614consecutive group of elements for which the corresponding condition did
4615hold". This could also be expressed as a separate paragraph
4616"Postcondition:".
4617h) If it is considered that the wording is unclear whether it declares
4618the element of a group which consists of only a single element
4619implicitly to be the first element of this group [Note: Such an
4620interpretation could eventually arise especially in case last - first ==
46211] , the following additional sentence is proposed: "If such a group of
4622elements consists of only a single element, this element is also
4623considered the first element."
4624</p>
4625
4626<p>
4627Change 25.2.8 [lib.alg.unique], paragraph 2 to:
4628"Returns: The iterator k."
4629</p>
4630
4631<p>
4632Add a separate paragraph "Notes:" as 25.2.8 [lib.alg.unique], paragraph
46332a or 3a, or a separate paragraph "Postcondition:" before 25.2.8
4634[lib.alg.unique], paragraph 2 (wording inside {} shall be eliminated if
4635the preceding expressions are used, or the preceding expressions shall
4636be eliminated if wording inside {} is used):
4637</p>
4638
4639<p>
4640"Notes:{Postcondition:} Stable: the relative order of the elements that
4641are placed into the subrange [first, return value {k}) shall be the same
4642as their relative order was in the original range [first, last) prior to
4643application of the algorithm."
4644</p>
4645
4646<p>Comments to the new wording:</p>
4647
4648<p>
4649a) It is assumed by the author that the algorithm was intended to be
4650stable.
4651In case this was not the intent, this paragraph becomes certainly
4652obsolete.
4653b) The wording "was ...  prior to application of the algorithm" is used
4654to explicitly distinguish the original range not only by means of
4655iterators, but also by a 'chronological' factor from the resulting range
4656[first, return value). It might be redundant.
4657</p>
4658
4659<p>
466025.2.8 [lib.alg.unique], paragraph 3:
4661</p>
4662<p>See DR 239.</p>
4663
4664<p>
46654) References to other DRs:
4666</p>
4667
4668<p>
4669See DR 202, but which does not address any of the problems described in
4670this Defect Report [Note: This DR is supposed to complement DR 202].
4671See DR 239.
4672See DR submitted by Thomas Mang regarding invalid iterator arithmetic
4673expressions.
4674</p>
4675
4676<p>
4677[1]:
4678The wording of these references is not always unambiguous, and provided
4679examples partially contradict verbal description of the algorithms,
4680because the verbal description resembles the problematic wording of
4681ISO/IEC 14882:2003.
4682</p>
4683
4684<p>
4685[2]:
4686Illustration of conforming implementations according to current wording:
4687</p>
4688
4689<p>
4690One way the author of this DR considers how this "elimination" could be
4691achieved by a conforming implementation according to current wording is
4692by substituting each r-element by _any_ s-element [Note: s...stay; any
4693non-r-element], since all r-elements are "eliminated".
4694</p>
4695
4696<p>
4697In case of a sequence consisting of elements being all 'equal' [Note:
4698See DR 202], substituting each r-element by the single s-element is the
4699only possible solution according to current wording.
4700</p>
4701<p><b>Proposed resolution:</b></p>
4702<p><b>Rationale:</b></p>
4703<p>The LWG believes the standard is sufficiently clear. No
4704implementers get it wrong, and changing it wouldn't cause any code to
4705change, so there is no real-world harm here.</p>
4706<hr>
4707<a name="491"><h3>491.&nbsp;std::list&lt;&gt;::unique incorrectly specified</h3></a><p><b>Section:</b>&nbsp;23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Thomas Mang&nbsp; <b>Date:</b>&nbsp;12 Dec 2004</p>
4708<p>In Section 23.2.2.4 [lib.list.ops], paragraphs 19 to 21 describe the
4709behavior of the std::list&lt;T, Allocator&gt;::unique operation. However, the
4710current wording is defective for various reasons.</p>
4711
4712
4713
4714<p>
47151) Analysis of current wording:
4716</p>
4717
4718<p>23.2.2.4 [lib.list.ops], paragraph 19:</p>
4719
4720<p>
4721Current wording says:
4722"Effects:  Eliminates all but the first element from every consecutive
4723group of equal elements referred to by the iterator i in the range
4724[first + 1, last) for which *i == *(i - 1) (for the version of unique
4725with no argument) or pred(*i, *(i -1)) (for the version of unique with a
4726predicate argument) holds."</p>
4727
4728<p>
4729This sentences makes use of the undefined term "Eliminates". Although it
4730is, to a certain degree, reasonable to consider the term "eliminate"
4731synonymous with "erase", using "Erase" in the first place, as the
4732wording of 23.2.2.4 [lib.list.ops], paragraph 15 does, would be clearer.</p>
4733
4734<p>
4735The range of the elements referred to by iterator i is "[first + 1,
4736last)". However, neither "first" nor "last" is defined.</p>
4737
4738<p>
4739The sentence makes three times use of iterator arithmetic expressions (
4740"first + 1", "*i == *(i - 1)", "pred(*i, *(i -1))" ) which is not
4741defined for bidirectional iterator [see DR submitted by Thomas Mang
4742regarding invalid iterator arithmetic expressions].</p>
4743
4744<p>
4745The same problems as pointed out in DR 202 (equivalence relation / order
4746of arguments for pred()) apply to this paragraph.</p>
4747
4748<p>
474923.2.2.4 [lib.list.ops], paragraph 20:
4750</p>
4751
4752<p>
4753Current wording says:
4754"Throws: Nothing unless an exception in thrown by *i == *(i-1) or
4755pred(*i, *(i - 1))"</p>
4756
4757<p>
4758The sentence makes two times use of invalid iterator arithmetic
4759expressions ( "*i == *(i - 1)", "pred(*i, *(i -1))" ).
4760</p>
4761<p>
4762[Note: Minor typos: "in" / missing dot at end of sentence.]
4763</p>
4764
4765<p>
476623.2.2.4 [lib.list.ops], paragraph 21:</p>
4767
4768<p>
4769Current wording says:
4770"Complexity: If the range (last - first) is not empty, exactly (last -
4771first) - 1 applications of the corresponding predicate, otherwise no
4772application of the predicate.</p>
4773
4774<p>
4775See DR 315 regarding "(last - first)" not yielding a range.</p>
4776
4777<p>
4778Invalid iterator arithmetic expression "(last - first) - 1" left .</p>
4779
4780
4781<p>2) Description of intended behavior:</p>
4782
4783<p>
4784For the rest of this Defect Report, it is assumed that "eliminate" is
4785supposed to be synonymous to "erase", that "first" is equivalent to an
4786iterator obtained by a call to begin(), "last" is equivalent to an
4787iterator obtained by a call to end(), and that all invalid iterator
4788arithmetic expressions are resolved as described in DR submitted by
4789Thomas Mang regarding invalid iterator arithmetic expressions.</p>
4790
4791<p>
4792Furthermore, the resolutions of DR 202 are considered regarding
4793equivalence relation and order of arguments for a call to pred.</p>
4794
4795<p>
4796All implementations known to the author of this Defect Report comply
4797with these assumptions, apart from the impact of the alternative
4798resolution of DR 202. Except for the changes implied by the resolutions
4799of DR 202, no impact on current code is expected.</p>
4800
4801<p>
48023) Proposed fixes:</p>
4803
4804<p>
4805Change 23.2.2.4 [lib.list.ops], paragraph 19 to:</p>
4806
4807<p>
4808"Effect: Erases all but the first element from every consecutive group
4809of elements, referred to by the iterator i in the range [begin(),
4810end()), for which the following conditions hold: *(i-1) == *i (for the
4811version of unique with no argument) or pred(*(i-1), *i) != false (for
4812the version of unique with a predicate argument)."</p>
4813
4814<p>
4815Comments to the new wording:</p>
4816
4817<p>
4818a) The new wording was influenced by DR 202 and the resolutions
4819presented there. If DR 202 is resolved in another way, the proposed
4820wording need also additional review.
4821b) "Erases" refers in the author's opinion unambiguously to the member
4822function "erase". In case there is doubt this might not be unamgibuous,
4823a direct reference to the member function "erase" is suggested [Note:
4824This would also imply a change of 23.2.2.4 [lib.list.ops], paragraph
482515.].
4826c) The expression "(i - 1)" was left, but is expected that DR submitted
4827by Thomas Mang regarding invalid iterator arithmetic expressions will
4828take this into account.
4829d) The wording "(for the version of unique with no argument)" and "(for
4830the version of unique with a predicate argument)" was kept consciously
4831for clarity.
4832e) "begin()" substitutes "first", and "end()" substitutes "last". The
4833range need adjustment from "[first + 1, last)" to "[begin(), end())" to
4834ensure a valid range in case of an empty list.
4835f) If it is considered that the wording is unclear whether it declares
4836the element of a group which consists of only a single element
4837implicitly to be the first element of this group [Note: Such an
4838interpretation could eventually arise especially in case size() == 1] ,
4839the following additional sentence is proposed: "If such a group of
4840elements consists of only a single element, this element is also
4841considered the first element."</p>
4842
4843<p>
4844Change 23.2.2.4 [lib.list.ops], paragraph 20 to:</p>
4845
4846<p>
4847"Throws: Nothing unless an exception is thrown by *(i-1) == *i or
4848pred(*(i-1), *i)."</p>
4849
4850<p>
4851Comments to the new wording:</p>
4852
4853<p>
4854a) The wording regarding the conditions is identical to proposed
485523.2.2.4 [lib.list.ops], paragraph 19. If 23.2.2.4 [lib.list.ops],
4856paragraph 19 is resolved in another way, the proposed wording need also
4857additional review.
4858b) The expression "(i - 1)" was left, but is expected that DR submitted
4859by Thomas Mang regarding invalid iterator arithmetic expressions will
4860take this into account.
4861c) Typos fixed.</p>
4862
4863<p>
4864Change 23.2.2.4 [lib.list.ops], paragraph 21 to:</p>
4865
4866<p>
4867"Complexity: If empty() == false, exactly size() - 1 applications of the
4868corresponding predicate, otherwise no applications of the corresponding
4869predicate."</p>
4870
4871<p>
4872Comments to the new wording:</p>
4873
4874<p>
4875a) The new wording is supposed to also replace the proposed resolution
4876of DR 315, which suffers from the problem of undefined "first" / "last".
4877</p>
4878
4879<p>
48805) References to other DRs:</p>
4881
4882<p>See DR 202.
4883See DR 239.
4884See DR 315.
4885See DR submitted by Thomas Mang regarding invalid iterator arithmetic
4886expressions.</p>
4887
4888<p><b>Proposed resolution:</b></p>
4889<p><b>Rationale:</b></p>
4890<p>"All implementations known to the author of this Defect Report
4891comply with these assumption", and "no impact on current code is
4892expected", i.e. there is no evidence of real-world confusion or
4893harm.</p>
4894<hr>
4895<a name="493"><h3>493.&nbsp;Undefined Expression in Input Iterator Note Title</h3></a><p><b>Section:</b>&nbsp;24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Chris Jefferson&nbsp; <b>Date:</b>&nbsp;13 Dec 2004</p>
4896<p>1) In 24.1.1/3, the following text is currently present.</p>
4897
4898<p>"Note: For input iterators, a==b does not imply ++a=++b (Equality does
4899not guarantee the substitution property or referential transparency)."</p>
4900
4901<p>However, when in Table 72, part of the definition of ++r is given as:</p>
4902
4903<p>"pre: r is dereferenceable.
4904post: any copies of the previous value of r are no longer required
4905either to be dereferenceable ..."</p>
4906
4907<p>While a==b does not imply that b is a copy of a, this statement should
4908perhaps still be made more clear.</p>
4909
4910<p>2) There are no changes to intended behaviour</p>
4911
4912<p>
49133) This Note should be altered to say "Note: For input iterators a==b,
4914when its behaviour is defined ++a==++b may still be false (Equality does
4915not guarantee the substitution property or referential transparency).</p>
4916
4917<p><b>Proposed resolution:</b></p>
4918<p><b>Rationale:</b></p>
4919<p>This is descriptive text, not normative, and the meaning is clear.</p>
4920<hr>
4921<a name="494"><h3>494.&nbsp;Wrong runtime complexity for associative container's insert and delete</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Hans B os&nbsp; <b>Date:</b>&nbsp;19 Dec 2004</p>
4922<p>According to [lib.associative.reqmts] table 69, the runtime comlexity
4923of insert(p, t) and erase(q) can be done in amortized constant time.</p>
4924
4925<p>It was my understanding that an associative container could be
4926implemented as a balanced binary tree.</p>
4927
4928<p>For inser(p, t), you 'll have to iterate to p's next node to see if t
4929can be placed next to p.  Furthermore, the insertion usually takes
4930place at leaf nodes. An insert next to the root node will be done at
4931the left of the root next node</p>
4932
4933<p>So when p is the root node you 'll have to iterate from the root to
4934its next node, which  takes O(log(size)) time in a balanced tree.</p>
4935
4936<p>If you insert all values with insert(root, t) (where root is the
4937root of the tree before insertion) then each insert takes O(log(size))
4938time.  The amortized complexity per insertion will be O(log(size))
4939also.</p>
4940
4941<p>For erase(q), the normal algorithm for deleting a node that has no
4942empty left or right subtree, is to iterate to the next (or previous),
4943which is a leaf node. Then exchange the node with the next and delete
4944the leaf node.  Furthermore according to DR 130, erase should return
4945the next node of the node erased.  Thus erasing the root node,
4946requires iterating to the next node.</p>
4947
4948<p>Now if you empty a map by deleting the root node until the map is
4949empty, each operation will take O(log(size)), and the amortized
4950complexity is still O(log(size)).</p>
4951
4952<p>The operations can be done in amortized constant time if iterating
4953to the next node can be done in (non amortized) constant time.  This
4954can be done by putting all nodes in a double linked list.  This
4955requires two extra links per node.  To me this is a bit overkill since
4956you can already efficiently insert or erase ranges with erase(first,
4957last) and insert(first, last).</p>
4958
4959<p><b>Proposed resolution:</b></p>
4960<p><b>Rationale:</b></p>
4961<p>Only "amortized constant" in special circumstances, and we believe
4962  that's implementable. That is: doing this N times will be O(N), not
4963  O(log N).</p>
4964<hr>
4965<a name="499"><h3>499.&nbsp;Std. doesn't seem to require stable_sort() to be stable!</h3></a><p><b>Section:</b>&nbsp;25.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.stable.sort"> [lib.stable.sort]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Prateek Karandikar&nbsp; <b>Date:</b>&nbsp;12 Apr 2005</p>
4966<blockquote>
4967<p>
496817.3.1.1 Summary</p>
4969
4970<p>
49711 The Summary provides a synopsis of the category, and introduces the
4972first-level subclauses. Each subclause also provides a summary, listing
4973the headers specified in the subclause and the library entities
4974provided in each header.
4975</p>
4976<p>
49772 Paragraphs labelled "Note(s):" or "Example(s):" are informative,
4978other paragraphs are normative.
4979</p>
4980</blockquote>
4981
4982<p>So this means that a "Notes" paragraph wouldn't be normative. </p>
4983
4984<blockquote>
4985<p>
498625.3.1.2 stable_sort
4987</p>
4988<pre>template&lt;class RandomAccessIterator&gt;
4989void stable_sort(RandomAccessIterat or first, RandomAccessIterator last);
4990
4991template&lt;class RandomAccessIterator, class Compare&gt;
4992void stable_sort(RandomAccessIterat or first, RandomAccessIterator last, Compare comp);
4993</pre>
4994<p>
49951 Effects: Sorts the elements in the range [first, last).
4996</p>
4997<p>
49982 Complexity: It does at most N(log N)^2 (where N == last - first)
4999comparisons; if enough extra memory is available, it is N log N.
5000</p>
5001<p>
50023 Notes: Stable: the relative order of the equivalent elements is
5003preserved.
5004</p>
5005</blockquote>
5006
5007<p>
5008The Notes para is informative, and nowhere else is stability mentioned above.
5009</p>
5010
5011<p>
5012Also, I just searched for the word "stable" in my copy of the Standard.
5013and the phrase "Notes: Stable: the relative order of the elements..."
5014is repeated several times in the Standard library clauses for
5015describing various functions. How is it that stability is talked about
5016in the informative paragraph? Or am I missing something obvious?
5017</p>
5018<p><b>Proposed resolution:</b></p>
5019<p>
5020</p>
5021<p><b>Rationale:</b></p>
5022<p>
5023This change has already been made.
5024</p>
5025<hr>
5026<a name="500"><h3>500.&nbsp;do_length cannot be implemented correctly</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Krzysztof �elechowski&nbsp; <b>Date:</b>&nbsp;24 May 2005</p>
5027<ol>
5028<li>codecvt::do_length is of type int;</li>
5029<li>it is assumed to be sort-of returning from_next - from of type ptrdiff_t;</li>
5030<li>ptrdiff_t cannot be cast to an int without data loss.</li>
5031</ol>
5032<p>
5033Contradiction.
5034</p>
5035<p><b>Proposed resolution:</b></p>
5036<p>
5037</p>
5038<hr>
5039<a name="501"><h3>501.&nbsp;Proposal: strengthen guarantees of lib.comparisons</h3></a><p><b>Section:</b>&nbsp;20.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.base"> [lib.base]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Me &lt;anti_spam_email2003@yahoo.com&gt;&nbsp; <b>Date:</b>&nbsp;7 Jun 2005</p>
5040<blockquote>
5041"For templates greater, less, greater_equal, and less_equal,
5042the specializations for any pointer type yield a total order, even if
5043the built-in operators &lt;, &gt;, &lt;=, &gt;= do not."
5044</blockquote>
5045
5046<p>
5047The standard should do much better than guarantee that these provide a
5048total order, it should guarantee that it can be used to test if memory
5049overlaps, i.e. write a portable memmove. You can imagine a platform
5050where the built-in operators use a uint32_t comparison (this tests for
5051overlap on this platform) but the less&lt;T*&gt; functor is allowed to be
5052defined to use a int32_t comparison. On this platform, if you use
5053std::less with the intent of making a portable memmove, comparison on
5054an array that straddles the 0x7FFFFFFF/0x8000000 boundary can give
5055incorrect results.
5056</p>
5057<p><b>Proposed resolution:</b></p>
5058<p>
5059Add a footnote to 20.5.3/8 saying:
5060</p>
5061
5062<blockquote>
5063Given a p1 and p2 such that p1 points to N objects of type T and p2
5064points to M objects of type T. If [p1,p1+N) does not overlap [p2,p2+M),
5065less returns the same value when comparing all pointers in [p1,p1+N) to
5066all pointers in [p2,p2+M). Otherwise, there is a value Q and a value R
5067such that less returns the same value when comparing all pointers in
5068[p1,p1+Q) to all pointers in [p2,p2+R) and an opposite value when
5069comparing all pointers in [p1+Q,p1+N) to all pointers in [p2+R,p2+M).
5070For the sake of completeness, the null pointer value (4.10) for T is
5071considered to be an array of 1 object that doesn't overlap with any
5072non-null pointer to T. less_equal, greater, greater_equal, equal_to,
5073and not_equal_to give the expected results based on the total ordering
5074semantics of less. For T of void, treat it as having similar semantics
5075as T of char i.e. less&lt;cv T*&gt;(a, b) gives the same results as less&lt;cv
5076void*&gt;(a, b) which gives the same results as less&lt;cv char*&gt;((cv
5077char*)(cv void*)a, (cv char*)(cv void*)b).
5078</blockquote>
5079
5080<p>
5081I'm also thinking there should be a footnote to 20.5.3/1 saying that if
5082A and B are similar types (4.4/4), comp&lt;A&gt;(a,b) returns the same value
5083as comp&lt;B&gt;(a,b) (where comp is less, less_equal, etc.). But this might
5084be problematic if there is some really funky operator overloading going
5085on that does different things based on cv (that should be undefined
5086behavior if somebody does that though). This at least should be
5087guaranteed for all POD types (especially pointers) that use the
5088built-in comparison operators.
5089</p>
5090
5091<p><b>Rationale:</b></p>
5092less is already required to provide a strict weak ordering which is good enough
5093to detect overlapping memory situations.
5094<hr>
5095<a name="504"><h3>504.&nbsp;Integer types in pseudo-random number engine requirements</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.req"> [tr.rand.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5096<p>
5097In [tr.rand.req], Paragraph 2 states that "... s is a value of integral type,
5098g is an ... object returning values of unsigned integral type ..."
5099</p>
5100<p><b>Proposed resolution:</b></p>
5101<p>
5102In 5.1.1 [tr.rand.req], Paragraph 2 replace
5103</p>
5104
5105<blockquote>
5106... s is a value of integral type, g is an lvalue of a type other than X that
5107defines a zero-argument function object returning values of <del>unsigned integral</del> type
5108<ins><tt>unsigned long int</tt></ins>,
5109...
5110</blockquote>
5111
5112<p>
5113In 5.1.1 [tr.rand.seq], Table 16, replace in the line for X(s)
5114</p>
5115
5116<blockquote>
5117creates an engine with the initial internal state
5118determined by <ins><tt>static_cast&lt;unsigned long&gt;(</tt></ins><tt><i>s</i></tt><ins><tt>)</tt></ins>
5119</blockquote>
5120
5121<p><i>[
5122Mont Tremblant:  Both s and g should be unsigned long.
5123This should refer to the constructor signatures. Jens  provided wording post Mont Tremblant.
5124]</i></p>
5125
5126<p><i>[
5127Berlin:  N1932 adopts the proposed resolution:  see 26.3.1.3/1e and Table 3 row 2. Moved
5128to Ready.
5129]</i></p>
5130
5131<p><b>Rationale:</b></p>
5132<p>
5133Jens:  Just requiring X(unsigned long) still makes it possible
5134for an evil library writer to also supply a X(int) that does something
5135unexpected.  The wording above requires that X(s) always performs
5136as if X(unsigned long) would have been called.  I believe that is
5137sufficient and implements our intentions from Mont Tremblant.  I
5138see no additional use in actually requiring a X(unsigned long)
5139signature.  u.seed(s) is covered by its reference to X(s), same
5140arguments.
5141</p>
5142<hr>
5143<a name="506"><h3>506.&nbsp;Requirements of Distribution parameter for variate_generator</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.var"> [tr.rand.var]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5144<p>
5145Paragraph 3 requires that template argument U (which corresponds to template
5146parameter Engine) satisfy all uniform random number generator requirements.
5147However, there is no  analogous requirement regarding the template argument
5148that corresponds to template parameter Distribution.  We believe there should
5149be, and that it should require that this template argument satisfy all random
5150distribution requirements.
5151</p>
5152<p><b>Proposed resolution:</b></p>
5153<p>
5154Consequence 1: Remove the precondition clauses [tr.rand.var]/16 and /18.
5155</p>
5156<p>
5157Consequence 2: Add max() and min() functions to those distributions that
5158do not already have them.
5159</p>
5160
5161<p><i>[
5162Mont Tremblant: Jens reccommends NAD, min/max not needed everywhere.
5163Marc supports having min and max to satisfy generic programming interface.
5164]</i></p>
5165
5166<p><b>Rationale:</b></p>
5167Berlin:  N1932 makes this moot: variate_generator has been eliminated.
5168<hr>
5169<a name="509"><h3>509.&nbsp;Uniform_int template parameters</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.7.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.dist.iunif"> [tr.rand.dist.iunif]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5170<p>
5171In [tr.rand.dist.iunif] the uniform_int distribution currently has a single
5172template parameter, IntType, used as the input_type and as the result_type
5173of the distribution.  We believe there is no reason to conflate these types
5174in this way.
5175</p>
5176<p><b>Proposed resolution:</b></p>
5177<p>
5178We recommend that there be a second template  parameter to
5179reflect the distribution�s input_type, and that the existing first template
5180parameter continue to reflect (solely) the result_type:
5181</p>
5182<blockquote><pre>template&lt; class IntType = int, UIntType = unsigned int &gt;
5183class uniform_int
5184{
5185public:
5186  // types
5187  typedef  UIntType  input_type;
5188  typedef  IntType   result_type;
5189</pre></blockquote>
5190
5191<p><i>[
5192Berlin: Moved to NAD.  N1932 makes this moot: the input_type template parameter has been
5193eliminated.
5194]</i></p>
5195
5196<hr>
5197<a name="510"><h3>510.&nbsp;Input_type for bernoulli_distribution</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.7.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.dist.bern"> [tr.rand.dist.bern]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5198<p>
5199In [tr.rand.dist.bern] the distribution currently requires;
5200</p>
5201<blockquote><pre>typedef  int  input_type;
5202</pre></blockquote>
5203<p><b>Proposed resolution:</b></p>
5204<p>
5205We believe this is an unfortunate choice, and recommend instead:
5206</p>
5207<blockquote><pre>typedef  unsigned int  input_type;
5208</pre></blockquote>
5209
5210<p><i>[
5211Berlin:  Moved to NAD. N1932 makes this moot: the input_type template parameter has been
5212eliminated.
5213]</i></p>
5214
5215<hr>
5216<a name="511"><h3>511.&nbsp;Input_type for binomial_distribution</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.7.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.dist.bin"> [tr.rand.dist.bin]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5217<p>
5218Unlike all other distributions in TR1, this binomial_distribution has an
5219implementation-defined  input_type.  We believe this is an unfortunate choice,
5220because it hinders users from writing portable code.  It also hinders the
5221writing of compliance tests.  We recommend instead:
5222</p>
5223<blockquote><pre>typedef  RealType  input_type;
5224</pre></blockquote>
5225<p>
5226While this choice is somewhat arbitrary (as it was for some of the other
5227distributions), we make  this particular choice because (unlike all other
5228distributions) otherwise this template would not publish its RealType
5229argument and so users could not write generic code that accessed this
5230second template parameter.  In this respect, the choice is consistent with
5231the other distributions in  TR1.
5232</p>
5233<p>
5234We have two reasons for recommending that a real type be specified instead.
5235One reason is  based specifically on characteristics of binomial distribution
5236implementations, while the other is based on mathematical characteristics of
5237probability distribution functions in general.
5238</p>
5239<p>
5240Implementations of binomial distributions commonly use Stirling approximations
5241for values in certain ranges.  It is far more natural to use real values to
5242represent these approximations than it would be to use integral values to do
5243so.  In other ranges, implementations reply on the Bernoulli  distribution to
5244obtain values.  While TR1�s bernoulli_distribution::input_type is specified as
5245int, we believe this would be better specified as double.
5246</p>
5247<p>
5248This brings us to our main point:  The notion of a random distribution rests
5249on the notion of a cumulative distribution function, which in turn mathematically
5250depends on a continuous dependent variable.  Indeed, such a distribution function
5251would be meaningless if it depended on  discrete values such as integers�and this
5252remains true even if the distribution function were to take discrete steps.
5253</p>
5254<p>
5255Although this note is specifically about binomial_distribution::input_type,
5256we intend to recommend that all of the random distributions� input_types be
5257specified as a real type (either a RealType template parameter, or double,
5258as appropriate).
5259</p>
5260<p>
5261Of the nine distributions in TR1, four already have this characteristic
5262(uniform_real, exponential_distribution, normal_distribution, and
5263gamma_distribution).  We have already argued the case for the binomial the
5264remaining four distributions.
5265</p>
5266<p>
5267In the case of uniform_int, we believe that the calculations to produce an
5268integer result in a  specified range from an integer in a different specified
5269range is best done using real arithmetic.  This is because it involves a
5270product, one of whose terms is the ratio of the extents of the two ranges.
5271Without real arithmetic, the results become less uniform: some numbers become
5272more  (or less) probable that they should be.  This is, of course, undesireable
5273behavior in a uniform distribution.
5274</p>
5275<p>
5276Finally, we believe that in the case of the bernoulli_distribution (briefly
5277mentioned earlier), as well as the cases of the geometric_distribution and the
5278poisson_distribution, it would be far more natural to have a real input_type.
5279This is because the most natural computation involves the  random number
5280delivered and the distribution�s parameter p (in the case of bernoulli_distribution,
5281for example, the computation is a comparison against p), and p is already specified
5282in each case as having some real type.
5283</p>
5284<p><b>Proposed resolution:</b></p>
5285<blockquote><pre>typedef  RealType  input_type;
5286</pre></blockquote>
5287
5288<p><i>[
5289Berlin:  Moved to NAD.  N1932 makes this moot: the input_type template parameter has been
5290eliminated.
5291]</i></p>
5292<hr>
5293<a name="512"><h3>512.&nbsp;Seeding subtract_with_carry_01 from a single unsigned long</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.eng.sub1"> [tr.rand.eng.sub1]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5294<p>
5295Paragraph 8 specifies the algorithm by which a subtract_with_carry_01  engine
5296is to be seeded given a single unsigned long.  This algorithm is seriously
5297flawed in the case where the engine parameter w (also known as word_size)
5298exceeds 31 [bits].  The key part of the paragraph reads:
5299</p>
5300<blockquote>
5301sets x(-r) ... x(-1) to (lcg(1)*2**(-w)) mod 1
5302</blockquote>
5303<p>
5304and so forth.
5305</p>
5306<p>
5307Since the specified linear congruential engine, lcg, delivers numbers with
5308a maximum of 2147483563 (just a shade under 31 bits), then when w is, for
5309example, 48, each of the x(i) will be less than 2**-17.  The consequence
5310is that roughly the first 400 numbers delivered will be  conspicuously
5311close to either zero or one.
5312</p>
5313<p>
5314Unfortunately, this is not an innocuous flaw:  One of the predefined engines
5315in [tr.rand.predef],  namely ranlux64_base_01, has w = 48 and would exhibit
5316this poor behavior, while the original N1378 proposal states that these
5317pre-defined engines are intended to be of "known good properties."
5318</p>
5319<p><b>Proposed resolution:</b></p>
5320<p>
5321In 5.1.4.4 [tr.rand.eng.sub1], replace the "effects" clause for
5322void seed(unsigned long value = 19780503) by
5323</p>
5324
5325<blockquote>
5326<i>Effects:</i> If <tt>value == 0</tt>, sets value to <tt>19780503</tt>. In any
5327case, <del>with a linear congruential generator <tt>lcg</tt>(i) having parameters
5328<tt><i>m<sub>lcg</sub></i> = 2147483563</tt>, <tt><i>a<sub>lcg</sub></i> = 40014</tt>,
5329<tt><i>c<sub>lcg</sub></i> = 0</tt>, and <tt><i>lcg</i>(0) = value</tt>,</del>
5330sets <ins>carry<tt>(-1)</tt> and</ins> <tt>x(-r) &#8230; x(-1)</tt>
5331<ins>as if executing</ins>
5332
5333<blockquote><pre><ins>
5334linear_congruential&lt;unsigned long, 40014, 0, 2147483563&gt; lcg(value);
5335seed(lcg);
5336</ins></pre></blockquote>
5337
5338<del>to <tt>(<i>lcg</i>(1) � 2<sup>-<i>w</i></sup>) mod 1
5339&#8230; (<i>lcg</i>(<i>r</i>) � 2<sup>-<i>w</i></sup>) mod 1</tt>,
5340respectively. If <tt><i>x</i>(-1) == 0</tt>, sets carry<tt>(-1) = 2<sup>-<i>w</i></sup></tt>,
5341else sets carry<tt>(-1) = 0</tt>.</del>
5342</blockquote>
5343
5344<p><i>[
5345Jens provided revised wording post Mont Tremblant.
5346]</i></p>
5347
5348<p><i>[
5349Berlin: N1932 adopts the originally-proposed resolution of the issue.
5350Jens's supplied wording is a clearer description of what is
5351intended.  Moved to Ready.
5352]</i></p>
5353
5354<p><b>Rationale:</b></p>
5355<p>
5356Jens: I'm using an explicit type here, because fixing the
5357prose 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
5358stricter) requirements we have for seed(Gen&amp;).
5359</p>
5360
5361<p><i>[
5362Portland:  Subsumed by N2111.
5363]</i></p>
5364<hr>
5365<a name="513"><h3>513.&nbsp;Size of state for subtract_with_carry_01</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.eng.sub1"> [tr.rand.eng.sub1]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5366<p>
5367Paragraph 3 begins:
5368</p>
5369<blockquote>
5370The size of the state is r.
5371</blockquote>
5372<p>
5373However, this is not quite consistent with the remainder of the paragraph
5374which specifies a total  of nr+1 items in the textual representation of
5375the state.  We recommend the sentence be corrected to match:
5376</p>
5377<blockquote>
5378The size of the state is nr+1.
5379</blockquote>
5380<p>
5381To give meaning to the coefficient n, it may be also desirable to move
5382n�s definition from later in the paragraph.  Either of the following
5383seem reasonable formulations:
5384</p>
5385<blockquote>
5386With n=..., the size of the state is nr+1.
5387</blockquote>
5388<blockquote>
5389The size of the state is nr+1, where n=... .
5390</blockquote>
5391<p>
5392</p>
5393<p><b>Proposed resolution:</b></p>
5394<p><i>[
5395Jens:  I plead for "NAD" on the grounds that "size of state" is only
5396used as an argument for big-O complexity notation, thus
5397constant factors and additions don't count.
5398]</i></p>
5399
5400<p><i>[
5401Berlin: N1932 adopts the proposed NAD.
5402]</i></p>
5403
5404<hr>
5405<a name="514"><h3>514.&nbsp;Size of state for subtract_with_carry</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.eng.sub"> [tr.rand.eng.sub]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5406<p>
5407Paragraph 2 begins:
5408</p>
5409<blockquote>
5410The size of the state is r.
5411</blockquote>
5412<p>
5413However, the next sentence specifies a total of r+1 items in the textual
5414representation of the state,  r specific x�s as well as a specific carry.
5415This makes a total of r+1 items that constitute the size of the state,
5416rather than r.
5417</p>
5418<p><b>Proposed resolution:</b></p>
5419<p>
5420We recommend the sentence be corrected to match:
5421</p>
5422<blockquote>
5423 The size of the state is r+1.
5424</blockquote>
5425
5426<p><i>[
5427Jens:  I plead for "NAD" on the grounds that "size of state" is only
5428used as an argument for big-O complexity notation, thus
5429constant factors and additions don't count.
5430]</i></p>
5431
5432<p><i>[
5433Berlin: N1932 adopts the proposed NAD.
5434]</i></p>
5435
5436<hr>
5437<a name="516"><h3>516.&nbsp;Seeding subtract_with_carry_01 using a generator</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.eng.sub1"> [tr.rand.eng.sub1]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5438<p>
5439Paragraph 6 says:
5440</p>
5441<blockquote>
5442... obtained by successive invocations of g, ...
5443</blockquote>
5444<p>
5445We recommend instead:
5446</p>
5447<blockquote>
5448... obtained by taking successive invocations of g mod 2**32, ...
5449</blockquote>
5450<p>
5451as the context seems to require only 32-bit quantities be used here.
5452</p>
5453<p><b>Proposed resolution:</b></p>
5454<p>
5455Berlin: N1932 adopts the proposed resultion: see 26.3.3.4/7.  Moved to Ready.
5456</p>
5457
5458<p><i>[
5459Portland:  Subsumed by N2111.
5460]</i></p>
5461<hr>
5462<a name="517"><h3>517.&nbsp;Should include name in external representation</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.req"> [tr.rand.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
5463<p>
5464The last two rows of Table 16 deal with the i/o requirements of an engine,
5465specifying that the textual representation of an engine�s state,
5466appropriately formatted, constitute the engine�s  external representation.
5467</p>
5468<p>
5469This seems adequate when an engine�s type is known.  However, it seems
5470inadequate in the  context of generic code, where it becomes useful and
5471perhaps even necessary to determine an engine�s type via input.
5472</p>
5473<p>
5474</p>
5475<p><b>Proposed resolution:</b></p>
5476<p>
5477We therefore recommend that, in each of these two rows of Table 16, the
5478text "textual representation" be expanded so as to read "engine name
5479followed by the textual representation."
5480</p>
5481
5482<p><i>[
5483Berlin: N1932 considers this NAD. This is a QOI issue.
5484]</i></p>
5485
5486<hr>
5487<a name="544"><h3>544.&nbsp;minor NULL problems in C.2</h3></a><p><b>Section:</b>&nbsp;C.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/diff.html#diff.library"> [diff.library]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;25 Nov 2005</p>
5488<p>
5489According to C.2.2.3, p1, "the macro NULL, defined in any of &lt;clocale&gt;,
5490&lt;cstddef&gt;, &lt;cstdio&gt;, &lt;cstdlib&gt;, &lt;cstring&gt;, &lt;ctime&gt;,
5491or &lt;cwchar&gt;." This is consistent with the C standard.
5492</p>
5493<p>
5494However, Table 95 in C.2 fails to mention &lt;clocale&gt; and &lt;cstdlib&gt;.
5495</p>
5496<p>
5497In addition, C.2, p2 claims that "The C++ Standard library provides
549854 standard macros from the C library, as shown in Table 95." While
5499table 95 does have 54 entries, since a couple of them (including the
5500NULL macro) are listed more than once, the actual number of macros
5501defined by the C++ Standard Library may not be 54.
5502</p>
5503<p><b>Proposed resolution:</b></p>
5504<p>
5505I propose we add &lt;clocale&gt; and &lt;cstdlib&gt; to Table 96 and remove the
5506number of macros from C.2, p2 and reword the sentence as follows:
5507</p>
5508<blockquote>
5509The C++ Standard library <del>provides 54 standard macros from</del>
5510<ins>defines a number macros corresponding to those defined by</ins> the C
5511<ins>Standard</ins> library, as shown in Table 96.
5512</blockquote>
5513
5514<p><i>[
5515Portland:  Resolution is considered editorial.  It will be incorporated into the WD.
5516]</i></p>
5517
5518<hr>
5519<a name="549"><h3>549.&nbsp;Undefined variable in binomial_distribution</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.7.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.dist.bin"> [tr.rand.dist.bin]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;10 Jan 2006</p>
5520<p>
5521Paragraph 1 says that "A binomial distributon random distribution produces
5522integer values i&gt;0 with p(i) = (n choose i) * p*i * (1-p)^(t-i), where t and
5523p are the parameters of the distribution. OK, that tells us what t, p, and i
5524are. What's n?
5525</p>
5526<p><b>Proposed resolution:</b></p>
5527<p>
5528Berlin: Typo: "n" replaced by "t" in N1932: see 26.3.7.2.2/1.
5529</p>
5530
5531<p><i>[
5532Portland:  Subsumed by N2111.
5533]</i></p>
5534<hr>
5535<a name="554"><h3>554.&nbsp;Problem with lwg DR 184 numeric_limits&lt;bool&gt;</h3></a><p><b>Section:</b>&nbsp;18.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.special"> [lib.numeric.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;29 Jan 2006</p>
5536<p>
5537I believe we have a bug in the resolution of:
5538<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#184">lwg 184</a>
5539(WP status).
5540</p>
5541
5542<p>
5543The resolution spells out each member of <tt>numeric_limits&lt;bool&gt;</tt>.
5544The part I'm having a little trouble with is:
5545</p>
5546<blockquote><pre>static const bool traps = false;
5547</pre></blockquote>
5548
5549<p>
5550Should this not be implementation defined?  Given:
5551</p>
5552
5553<blockquote><pre>int main()
5554{
5555     bool b1 = true;
5556     bool b2 = false;
5557     bool b3 = b1/b2;
5558}
5559</pre></blockquote>
5560
5561<p>
5562If this causes a trap, shouldn't <tt>numeric_limits&lt;bool&gt;::traps</tt> be
5563<tt>true</tt>?
5564</p>
5565<p><b>Proposed resolution:</b></p>
5566<p>
5567Change 18.2.1.5p3:
5568</p>
5569
5570<blockquote>
5571-3- The specialization for <tt>bool</tt> shall be provided as follows:
5572<blockquote><pre>namespace std {
5573   template &lt;&gt; class numeric_limits&lt;bool&gt; {
5574      ...
5575      static const bool traps = <del>false</del> <ins><i>implementation-defined</i></ins>;
5576      ...
5577   };
5578}
5579</pre></blockquote>
5580</blockquote>
5581
5582<p><i>[
5583Redmond:  NAD because traps refers to values, not operations.  There is no bool
5584value that will trap.
5585]</i></p>
5586
5587<hr>
5588<a name="555"><h3>555.&nbsp;TR1, 8.21/1: typo</h3></a><p><b>Section:</b>&nbsp;TR1 8.21 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.c99.boolh"> [tr.c99.boolh]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;Paolo Carlini&nbsp; <b>Date:</b>&nbsp;2 Feb 2006</p>
5589<p>
5590This one, if nobody noticed it yet, seems really editorial:
5591s/cstbool/cstdbool/
5592</p>
5593<p><b>Proposed resolution:</b></p>
5594<p>
5595Change 8.21p1:
5596</p>
5597<blockquote>
5598-1- The header behaves as if it defines the additional macro defined in
5599<tt>&lt;cst<ins>d</ins>bool&gt;</tt> by including the header <tt>&lt;cstdbool&gt;</tt>.
5600</blockquote>
5601
5602<p><i>[
5603Redmond:  Editorial.
5604]</i></p>
5605
5606<hr>
5607<a name="558"><h3>558.&nbsp;lib.input.iterators Defect</h3></a><p><b>Section:</b>&nbsp;24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>&nbsp; <b>Submitter:</b>&nbsp;David Abrahams&nbsp; <b>Date:</b>&nbsp;9 Feb 2006</p>
5608<blockquote>
5609<p>
5610  24.1.1 Input iterators [lib.input.iterators]
5611</p>
5612<p>
5613  1 A class or a built-in type X satisfies the requirements of an
5614  input iterator for the value type T if the following expressions are
5615  valid, where U is the type of any specified member of type T, as
5616  shown in Table 73.
5617</p>
5618</blockquote>
5619<p>
5620There is no capital U used in table 73.  There is a lowercase u, but
5621that is clearly not meant to denote a member of type T.  Also, there's
5622no description in 24.1.1 of what lowercase a means.  IMO the above
5623should have been...Hah, a and b are already covered in 24.1/11, so maybe it
5624should have just been:
5625</p>
5626<p><b>Proposed resolution:</b></p>
5627<p>
5628Change 24.1.1p1:
5629</p>
5630<blockquote>
5631-1- A class or a built-in type <tt>X</tt> satisfies the requirements of an
5632input iterator for the value type <tt>T</tt> if the following expressions
5633are valid<del>, where <tt>U</tt> is the type of any specified member of type
5634<tt>T</tt>,</del> as shown in Table 73.
5635</blockquote>
5636
5637<p><i>[
5638Portland: Editorial.
5639]</i></p>
5640
5641<hr>
5642<a name="569"><h3>569.&nbsp;Postcondition for basic_ios::clear(iostate) incorrectly stated</h3></a><p><b>Section:</b>&nbsp;27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>&nbsp; <b>Submitter:</b>&nbsp;Seungbeom Kim&nbsp; <b>Date:</b>&nbsp;10 Mar 2006</p>
5643<p>
5644Section: 27.4.4.3 [lib.iostate.flags]
5645</p>
5646<p>
5647Paragraph 4 says:
5648</p>
5649<blockquote>
5650<blockquote><pre>void clear(iostate <i>state</i> = goodbit);
5651</pre></blockquote>
5652<p>
5653<i>Postcondition:</i> If <tt>rdbuf()!=0</tt> then <tt><i>state</i> == rdstate();</tt>
5654otherwise <tt>rdstate()==<i>state</i>|ios_base::badbit</tt>.
5655</p>
5656</blockquote>
5657
5658<p>
5659The postcondition "rdstate()==state|ios_base::badbit" is parsed as
5660"(rdstate()==state)|ios_base::badbit", which is probably what the
5661committee meant.
5662</p>
5663<p><b>Proposed resolution:</b></p>
5664<p><b>Rationale:</b></p>
5665<p>
5666This is a duplicate of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#272">272</a>.
5667</p>
5668<p>----- End of document -----</p>
5669</body></html>