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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>C++ Standard Evolution Active Issues List</title>
<style type="text/css">
p {text-align:justify}
li {text-align:justify}
blockquote.note
{
background-color:#E0E0E0;
padding-left: 15px;
padding-right: 15px;
padding-top: 1px;
padding-bottom: 1px;
}
ins {background-color:#A0FFA0}
del {background-color:#FFA0A0}
</style>
</head>
<body>
<table>
<tr>
<td align="left">Doc. no.</td>
<td align="left">N3836</td>
</tr>
<tr>
<td align="left">Date:</td>
<td align="left">2014-01-16</td>
</tr>
<tr>
<td align="left">Project:</td>
<td align="left">Programming Language C++</td>
</tr>
<tr>
<td align="left">Reply to:</td>
<td align="left">Ville Voutilainen <<a href="mailto:ville.voutilainen@gmail.com">ville.voutilainen@gmail.com</a>></td>
</tr>
</table>
<h1>C++ Standard Evolution Active Issues List (Revision R05)</h1>
<p>Revised 2014-01-16 at 19:01:45 UTC</p>
<p>Reference ISO/IEC IS 14882:2003(E)</p>
<p>Also see:</p>
<ul>
<li><a href="ewg-toc.html">Table of Contents</a> for all evolution issues.</li>
<li><a href="ewg-index.html">Index by Section</a> for all evolution issues.</li>
<li><a href="ewg-status.html">Index by Status</a> for all evolution issues.</li>
<li><a href="ewg-complete.html">Evolution Completed Issues List</a></li>
<li><a href="ewg-closed.html">Evolution Closed Issues List</a></li>
</ul>
<p>The purpose of this document is to record the status of issues
which have come before the Evolution Working Group (EWG) of the INCITS PL22.16
and ISO WG21 C++ Standards Committee. Issues represent
potential defects in the ISO/IEC IS 14882:2003(E) document,
and proposed extensions to it.
</p>
<p>This document contains only evolution issues which are actively being
considered by the Evolution Working Group, i.e., issues which have a
status of <a href="ewg-active.html#New">New</a>, <a href="ewg-active.html#Open">Open</a>,
<a href="ewg-active.html#Ready">Ready</a>, or <a href="ewg-active.html#Review">Review</a>. See
<a href="ewg-complete.html">Evolution Completed Issues List</a> for issues considered completed (adopted) and
<a href="ewg-closed.html">Evolution Closed Issues List</a> for issues considered closed (rejected).</p>
<p>The issues in these lists are not necessarily formal ISO Defect
Reports (DR's). While some issues will eventually be elevated to
official Defect Report status, other issues will be disposed of in
other ways. See <a href="#Status">Issue Status</a>.</p>
<p>This document includes <i>[bracketed italicized notes]</i> as a
reminder to the EWG of current progress on issues. Such notes are
strictly unofficial and should be read with caution as they may be
incomplete or incorrect. Be aware that EWG support for a particular
resolution can quickly change if new viewpoints or killer examples are
presented in subsequent discussions.</p>
<p>For the most current official version of this document see
<a href="http://www.open-std.org/jtc1/sc22/wg21/">http://www.open-std.org/jtc1/sc22/wg21/</a>.
Requests for further information about this document should include
the document number above, reference ISO/IEC 14882:2003(E), and be
submitted to Information Technology Industry Council (ITI), 1250 Eye
Street NW, Washington, DC 20005.</p>
<p>Public information as to how to obtain a copy of the C++ Standard,
join the standards committee, submit an issue, or comment on an issue
can be found in the comp.std.c++ FAQ.
</p>
<p><a name="submit_issue"></a><b>How to submit an issue</b></p>
<ol style="list-style-type:upper-alpha">
<li><a name="submit_issue_A"></a>
Mail your issue to the author of this list.
</li>
<li><a name="submit_issue_B"></a>
Specify a short descriptive title. If you fail to do so, the subject line of your
mail will be used as the issue title.
</li>
<li><a name="submit_issue_C"></a>
If the "From" on your email is not the name you wish to appear as issue submitter,
then specify issue submitter.
</li>
<li><a name="submit_issue_D"></a>
Provide a brief discussion of the problem you wish to correct. Refer to the latest
working draft or standard using [section.tag] and paragraph numbers where appropriate.
</li>
<li><a name="submit_issue_E"></a>
Provide proposed wording. This should indicate exactly how you want the standard
to be changed. General solution statements belong in the discussion area. This
area contains very clear and specific directions on how to modify the current
draft. If you are not sure how to word a solution, you may omit this part.
But your chances of a successful issue greatly increase if you attempt wording.
</li>
<li><a name="submit_issue_F"></a>
It is not necessary for you to use html markup. However, if you want to, you can
<ins><ins>insert text like this</ins></ins> and <del><del>delete text like
this</del></del>. The only strict requirement is to communicate clearly to
the list maintainer exactly how you want your issue to look.
</li>
<li><a name="submit_issue_G"></a>
It is not necessary for you to specify other html font/formatting
mark-up, but if you do the list maintainer will attempt to respect your
formatting wishes (as described by html markup, or other common idioms).
</li>
<li><a name="submit_issue_H"></a>
It is not necessary for you to specify open date or last modified date (the date
of your mail will be used).
</li>
<li><a name="submit_issue_I"></a>
It is not necessary for you to cross reference other issues, but you can if you
like. You do not need to form the hyperlinks when you do, the list maintainer will
take care of that.
</li>
<li><a name="submit_issue_J"></a>
One issue per email is best.
</li>
<li><a name="submit_issue_K"></a>
Between the time you submit the issue, and the next mailing deadline
(date at the top of the Revision History), you <em>own</em> this issue.
You control the content, the stuff that is right, the stuff that is
wrong, the format, the misspellings, etc. You can even make the issue
disappear if you want. Just let the list maintainer know how you want
it to look, and he will try his best to accommodate you. After the
issue appears in an official mailing, you no longer enjoy exclusive
ownership of it.
</li>
</ol>
<h2>Revision History</h2>
<ul>
<li>R05: 2014-01-17 pre-Issaquah mailing<ul>
<li><b>Summary:</b><ul>
<li>49 open issues, up by 3.</li>
<li>30 closed issues, up by 0.</li>
<li>79 issues total, up by 3.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following 3 New issues: <a href="ewg-active.html#77">77</a>, <a href="ewg-active.html#78">78</a>, <a href="ewg-active.html#79">79</a>.</li>
<li>Changed the following issue from New to Open: <a href="ewg-active.html#72">72</a>.</li>
<li>Changed the following issue from Ready to Open: <a href="ewg-active.html#41">41</a>.</li>
</ul></li>
</ul>
</li>
<li>R04:
<ul>
<li>R04: 2013-10-11 post-Chicago mailing<ul>
<li><b>Summary:</b><ul>
<li>46 open issues, down by 9.</li>
<li>30 closed issues, up by 12.</li>
<li>76 issues total, up by 3.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following 3 Open issues: <a href="ewg-active.html#74">74</a>, <a href="ewg-active.html#75">75</a>, <a href="ewg-active.html#76">76</a>.</li>
<li>Changed the following 4 issues from New to NAD: <a href="ewg-closed.html#12">12</a>, <a href="ewg-closed.html#68">68</a>, <a href="ewg-closed.html#69">69</a>, <a href="ewg-closed.html#73">73</a>.</li>
<li>Changed the following 2 issues from Open to NAD: <a href="ewg-closed.html#32">32</a>, <a href="ewg-closed.html#33">33</a>.</li>
<li>Changed the following 6 issues from New to Open: <a href="ewg-active.html#2">2</a>, <a href="ewg-active.html#17">17</a>, <a href="ewg-active.html#19">19</a>, <a href="ewg-active.html#23">23</a>, <a href="ewg-active.html#52">52</a>, <a href="ewg-active.html#71">71</a>.</li>
<li>Changed the following 4 issues from Open to WP: <a href="ewg-complete.html#18">18</a>, <a href="ewg-complete.html#21">21</a>, <a href="ewg-complete.html#22">22</a>, <a href="ewg-complete.html#27">27</a>.</li>
<li>Changed the following 2 issues from Ready to WP: <a href="ewg-complete.html#3">3</a>, <a href="ewg-complete.html#20">20</a>.</li>
</ul></li>
</ul>
</li>
</ul>
</li>
<li>R03:
<ul>
<li>R03: 2013-08-27 pre-Chicago mailing<ul>
<li><b>Summary:</b><ul>
<li>55 open issues, up by 7.</li>
<li>18 closed issues, up by 0.</li>
<li>73 issues total, up by 7.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following 7 New issues: <a href="ewg-active.html#67">67</a>, <a href="ewg-active.html#68">68</a>, <a href="ewg-active.html#69">69</a>, <a href="ewg-active.html#70">70</a>, <a href="ewg-active.html#71">71</a>, <a href="ewg-active.html#72">72</a>, <a href="ewg-active.html#73">73</a>.</li>
</ul></li>
</ul>
</li>
</ul>
</li>
<li>R02:
2013-05-06 post-Bristol mailing
<ul>
<li><b>Summary:</b><ul>
<li>49 open issues, up by 2.</li>
<li>18 closed issues, up by 17.</li>
<li>67 issues total, up by 19.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following 3 NAD issues: <a href="ewg-closed.html#53">53</a>, <a href="ewg-closed.html#54">54</a>, <a href="ewg-closed.html#55">55</a>.</li>
<li>Added the following 6 New issues: <a href="ewg-active.html#49">49</a>, <a href="ewg-active.html#50">50</a>, <a href="ewg-active.html#51">51</a>, <a href="ewg-active.html#52">52</a>, <a href="ewg-active.html#59">59</a>, <a href="ewg-active.html#65">65</a>.</li>
<li>Added the following 7 Open issues: <a href="ewg-active.html#56">56</a>, <a href="ewg-active.html#57">57</a>, <a href="ewg-active.html#58">58</a>, <a href="ewg-active.html#60">60</a>, <a href="ewg-active.html#63">63</a>, <a href="ewg-active.html#66">66</a>, <a href="ewg-active.html#66">66</a>.</li>
<li>Added the following 3 WP issues: <a href="ewg-complete.html#61">61</a>, <a href="ewg-complete.html#62">62</a>, <a href="ewg-complete.html#64">64</a>.</li>
<li>Changed the following 5 issues from New to NAD: <a href="ewg-closed.html#31">31</a>, <a href="ewg-closed.html#36">36</a>, <a href="ewg-closed.html#37">37</a>, <a href="ewg-closed.html#38">38</a>, <a href="ewg-closed.html#47">47</a>.</li>
<li>Changed the following 8 issues from New to Open: <a href="ewg-active.html#14">14</a>, <a href="ewg-active.html#30">30</a>, <a href="ewg-active.html#32">32</a>, <a href="ewg-active.html#33">33</a>, <a href="ewg-active.html#34">34</a>, <a href="ewg-active.html#35">35</a>, <a href="ewg-active.html#43">43</a>, <a href="ewg-active.html#48">48</a>.</li>
<li>Changed the following 6 issues from New to Ready: <a href="ewg-active.html#40">40</a>, <a href="ewg-active.html#41">41</a>, <a href="ewg-active.html#42">42</a>, <a href="ewg-active.html#44">44</a>, <a href="ewg-active.html#45">45</a>, <a href="ewg-active.html#46">46</a>.</li>
<li>Changed the following 2 issues from Open to WP: <a href="ewg-complete.html#16">16</a>, <a href="ewg-complete.html#25">25</a>.</li>
<li>Changed the following 4 issues from Ready to WP: <a href="ewg-complete.html#1">1</a>, <a href="ewg-complete.html#6">6</a>, <a href="ewg-complete.html#7">7</a>, <a href="ewg-complete.html#13">13</a>.</li>
</ul></li>
</ul>
</li>
<li>R01:
2013-03-18 Pre-Bristol mailing
<ul>
<li><b>Summary:</b><ul>
<li>47 open issues, up by 47.</li>
<li>1 closed issues, up by 1.</li>
<li>48 issues total, up by 48.</li>
</ul></li>
<li><b>Details:</b><ul>
<li>Added the following NAD issue: <a href="ewg-closed.html#39">39</a>.</li>
<li>Added the following 32 New issues: <a href="ewg-active.html#2">2</a>, <a href="ewg-active.html#5">5</a>, <a href="ewg-active.html#8">8</a>, <a href="ewg-active.html#10">10</a>, <a href="ewg-active.html#11">11</a>, <a href="ewg-active.html#12">12</a>, <a href="ewg-active.html#14">14</a>, <a href="ewg-active.html#15">15</a>, <a href="ewg-active.html#17">17</a>, <a href="ewg-active.html#19">19</a>, <a href="ewg-active.html#23">23</a>, <a href="ewg-active.html#24">24</a>, <a href="ewg-active.html#26">26</a>, <a href="ewg-active.html#28">28</a>, <a href="ewg-active.html#30">30</a>, <a href="ewg-active.html#31">31</a>, <a href="ewg-active.html#32">32</a>, <a href="ewg-active.html#33">33</a>, <a href="ewg-active.html#34">34</a>, <a href="ewg-active.html#35">35</a>, <a href="ewg-active.html#36">36</a>, <a href="ewg-active.html#37">37</a>, <a href="ewg-active.html#38">38</a>, <a href="ewg-active.html#40">40</a>, <a href="ewg-active.html#41">41</a>, <a href="ewg-active.html#42">42</a>, <a href="ewg-active.html#43">43</a>, <a href="ewg-active.html#44">44</a>, <a href="ewg-active.html#45">45</a>, <a href="ewg-active.html#46">46</a>, <a href="ewg-active.html#47">47</a>, <a href="ewg-active.html#48">48</a>.</li>
<li>Added the following 9 Open issues: <a href="ewg-active.html#4">4</a>, <a href="ewg-active.html#9">9</a>, <a href="ewg-active.html#16">16</a>, <a href="ewg-active.html#18">18</a>, <a href="ewg-active.html#21">21</a>, <a href="ewg-active.html#22">22</a>, <a href="ewg-active.html#25">25</a>, <a href="ewg-active.html#27">27</a>, <a href="ewg-active.html#29">29</a>.</li>
<li>Added the following 6 Ready issues: <a href="ewg-active.html#1">1</a>, <a href="ewg-active.html#3">3</a>, <a href="ewg-active.html#6">6</a>, <a href="ewg-active.html#7">7</a>, <a href="ewg-active.html#13">13</a>, <a href="ewg-active.html#20">20</a>.</li>
</ul></li>
</ul>
</li>
</ul>
</li>
</ul>
<h2><a name="Status"></a>Issue Status</h2>
<p><b><a name="New">New</a></b> - The issue has not yet been
reviewed by the EWG. Any <b>Wording available</b> is purely a
suggestion from the issue submitter, and should not be construed as
the view of EWG.</p>
<p><b><a name="Open">Open</a></b> - The EWG has discussed the issue
but is not yet ready to move the issue forward. There are several
possible reasons for open status:</p>
<ul>
<li>Consensus may have not yet have been reached as to how to deal
with the issue.</li>
<li>Informal consensus may have been reached, but the EWG awaits
exact resolution for review.</li>
<li>The EWG wishes to consult additional technical experts before
proceeding.</li>
<li>The issue may require further study.</li>
</ul>
<p>A <b>Wording available</b> for an open issue is still not be
construed as the view of EWG. Comments on the current state of
discussions are often given at the end of open issues in an italic
font. Such comments are for information only and should not be given
undue importance.</p>
<p><b><a name="Deferred">Deferred</a></b> - The EWG has discussed the issue,
is not yet ready to move the issue forward, but neither does it deem the
issue significant enough to delay publishing a standard or Technical Report.
A typical deferred issue would be seeking to clarify wording that might be
technically correct, but easily mis-read.</p>
<p>A <b>Wording available</b> for a deferred issue is still not be
construed as the view of EWG. Comments on the current state of
discussions are often given at the end of open issues in an italic
font. Such comments are for information only and should not be given
undue importance.</p>
<p><b><a name="Dup">Dup</a></b> - The EWG has reached consensus that
the issue is a duplicate of another issue, and will not be further
dealt with. A <b>Rationale</b> identifies the duplicated issue's
issue number. </p>
<p><b><a name="NAD">NAD</a></b> - The EWG has reached consensus that
the issue is not a defect in the Standard nor is it an extension
the EWG deems acceptable.</p>
<p><b><a name="Review">Review</a></b> - Exact resolution is now
available for review on an issue for which the EWG previously reached
informal consensus.</p>
<p><b><a name="Ready">Ready</a></b> - The EWG has reached consensus
that the issue is an extension that can go forward to Core, Library,
or a Study Group for further processing.</p>
<p><b><a name="Resolved">Resolved</a></b> - The EWG has reached consensus
that the issue is a defect in or an acceptable extension to the Standard,
but the resolution adopted to
resolve the issue came via some other mechanism than this issue in the
list - typically by applying a formal paper, occasionally as a side effect
of consolidating several interacting issue resolutions into a single issue.</p>
<p><b><a name="DR">DR</a></b> - (Defect Report) - It's not expected
that the EWG would handle Defect Reports.</p>
<p><b><a name="WP">WP</a></b> - (Working Paper) - The proposed
resolution has not been accepted as a Technical Corrigendum, but
the full WG21/PL22.16 committee has voted to apply the issue's resolution
to the working paper.</p>
<p><b>Tentatively</b> - This is a <i>status qualifier</i>. The issue has
been reviewed online, or at an unofficial meeting, but not in an official meeting, and some support has been formed
for the qualified status. Tentatively qualified issues may be moved to the unqualified status
and forwarded to full committee (if Ready) within the same meeting. Unlike Ready issues, Tentatively Ready issues
will be reviewed in subcommittee prior to forwarding to full committee. When a status is
qualified with Tentatively, the issue is still considered active.</p>
<p><b>Pending</b> - This is a <i>status qualifier</i>. When prepended to
a status this indicates the issue has been
processed by the committee, and a decision has been made to move the issue to
the associated unqualified status. However for logistical reasons the indicated
outcome of the issue has not yet appeared in the latest working paper.
<p>Issues are always given the status of <a href="ewg-active.html#New">New</a> when
they first appear on the issues list. They may progress to
<a href="ewg-active.html#Open">Open</a> or <a href="ewg-active.html#Review">Review</a> while the EWG
is actively working on them. When the EWG has reached consensus on
the disposition of an issue, the status will then change to
<a href="ewg-active.html#Dup">Dup</a>, <a href="ewg-active.html#NAD">NAD</a>, or
<a href="ewg-active.html#Ready">Ready</a> as appropriate. Once the full J16 committee votes to
forward Ready issues to the Project Editor, they are given the
status of Defect Report ( <a href="ewg-active.html#DR">DR</a>). These in turn may
become the basis for Technical Corrigenda (<a href="ewg-active.html#TC1">TC1</a>),
or are closed without action other than a Record of Response
(<a href="ewg-active.html#Resolved">Resolved</a> ). The intent of this EWG process is that
issues which are defects in or accepted extensions to the Standard move to the
formal ISO DR status.
</p>
<h2>Active Issues</h2>
<hr>
<h3><a name="2"></a>2. N3387 Overload resolution tiebreakers for integer types</h3>
<p><b>Section:</b> 4.13 [conv.rank] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Jens Maurer <b>Opened:</b> 2012-09-12 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3387.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3387.html</a>
</p>
<p>
Deemed post-C++14 material in Chicago 2013.
</p>
<p><b>Wording available:</b></p>
<p>The paper contains the proposed wording.</p>
<hr>
<h3><a name="4"></a>4. N3396 Dynamic memory allocation for over-aligned data</h3>
<p><b>Section:</b> 18.6 [support.dynamic] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Clark Nelson <b>Opened:</b> 2012-08-30 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3396.htm">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3396.htm</a>
</p>
<p>Reviewed by EWG in Portland, author encouraged to revise.</p>
<p>Deemed post-C++14 material in Chicago 2013. Has an associated
NB comment, FI 16, although the comment is rejected for C++14.</p>
<p><b>Wording available:</b></p>
<p>The paper contains the proposed wording that is to be revised.</p>
<hr>
<h3><a name="5"></a>5.
N3400 A proposal for eliminating the underscore madness that library writers have to suffer</h3>
<p><b>Section:</b> 16.3 [cpp.replace] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Jonathan de Boyne Pollard <b>Opened:</b> 2012-09-21 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3400.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3400.html</a>
<p><b>Wording available:</b></p>
<p>The paper contains the proposed wording.</p>
<hr>
<h3><a name="8"></a>8.
N3492, N3403 Use Cases for Compile-Time Reflection
</h3>
<p><b>Section:</b> 18 [language.support] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Mike Spertus <b>Opened:</b> 2012-09-22 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3403.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3403.pdf</a>
</p>
<p>
<a href="http://open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3492.pdf">http://open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3492.pdf</a>
</p>
<p>Not reviewed by EWG yet, to be handled by the Reflection Study Group (SG7).</p>
<hr>
<h3><a name="9"></a>9.
N3601 Implicit template parameters, N3405 Template Tidbits
</h3>
<p><b>Section:</b> 14 [temp] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Mike Spertus <b>Opened:</b> 2012-09-22 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3405.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3405.html</a>
</p>
<p>
<a href="http://open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3601.html">http://open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3601.html</a>
</p>
<p>EWG review started, not completed yet. Likely needs a follow-up paper.</p>
<p>
Bristol 2013: Encouraged to pursue further. Template parameter deduction
for constructors has been split into EWG Issue <a href="ewg-active.html#60">60</a>.
</p>
<hr>
<h3><a name="10"></a>10.
N3407 Proposal to Add Decimal Floating Point Support to C++
</h3>
<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Dietmar Kühl <b>Opened:</b> 2012-09-14 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all other</b> <a href="ewg-index.html#library">issues</a> in [library].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3407.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3407.html</a>
<p>Handled by the Numerics Study Group (SG6).</p>
<hr>
<h3><a name="11"></a>11.
N3409 Strict Fork-Join Parallelism
</h3>
<p><b>Section:</b> 1.10 [intro.multithread] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2012-09-24 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#intro.multithread">active issues</a> in [intro.multithread].</p>
<p><b>View all other</b> <a href="ewg-index.html#intro.multithread">issues</a> in [intro.multithread].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3409.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3409.pdf</a>
<p>Handled by the Concurrency Study Group (SG1)</p>
<hr>
<h3><a name="14"></a>14.
N3413 Allowing arbitrary literal types for non-type template parameters
</h3>
<p><b>Section:</b> 14.1 [temp.param] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Jens Maurer <b>Opened:</b> 2012-09-19 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#temp.param">active issues</a> in [temp.param].</p>
<p><b>View all other</b> <a href="ewg-index.html#temp.param">issues</a> in [temp.param].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3413.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3413.html</a>
</p>
<p>
Bristol 2013: Maurer expressed surprise at the paper being under discussion, and explained that he doesn't think it can be made to work under current linker environments, and further explained that user-defined equality operators cause confusion and surprises. Maurer said that he'd want Stroustrup to clarify which parts of the paper he would want.
</p>
<p>
Two-way Straw polls:
</p>
<p>
Rules for agument expressions:
</p>
<p>
F: 5 A: 0
</p>
<p>
Structs without operator==
</p>
<p>
F: 0 A: 0
</p>
<p>
Structs with operator==
</p>
<p>
F: 1 A: 3
</p>
<p>
The issue is not pushed at this time.
</p>
<p>
Deemed post-C++14 material in Chicago 2013, Stroustrup expressed
interest in writing papers about the subject targeting C++17.
</p>
<p><b>Wording available:</b></p>
The paper contains the proposed wording.
<hr>
<h3><a name="15"></a>15.
N3416 Packaging Parameter Packs
</h3>
<p><b>Section:</b> 14.1 [temp.param] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Mike Spertus <b>Opened:</b> 2012-09-21 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#temp.param">active issues</a> in [temp.param].</p>
<p><b>View all other</b> <a href="ewg-index.html#temp.param">issues</a> in [temp.param].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3416.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3416.html</a>
<hr>
<h3><a name="17"></a>17.
N3419 Vector loops and Parallel Loops
</h3>
<p><b>Section:</b> 1.10 [intro.multithread] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Robert Geva <b>Opened:</b> 2012-09-21 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#intro.multithread">active issues</a> in [intro.multithread].</p>
<p><b>View all other</b> <a href="ewg-index.html#intro.multithread">issues</a> in [intro.multithread].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3419.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3419.pdf</a>
<p>
Handled by the Concurrency Study Group (SG1).
</p>
<hr>
<h3><a name="19"></a>19.
N3429 A C++ Library Solution To Parallelism
</h3>
<p><b>Section:</b> 30 [thread] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Artur Laksberg <b>Opened:</b> 2012-09-21 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3429.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3429.pdf</a>
<p>
Handled by the Concurrency Study Group (SG1).
</p>
<p><b>Wording available:</b></p>
<p>The paper contains the proposed wording.</p>
<hr>
<h3><a name="23"></a>23.
N3437 Type Name Strings For C++
</h3>
<p><b>Section:</b> 20.9 [meta] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Axel Naumann <b>Opened:</b> 2012-09-24 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#meta">active issues</a> in [meta].</p>
<p><b>View all other</b> <a href="ewg-index.html#meta">issues</a> in [meta].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3437.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3437.pdf</a>
<p>
Not reviewed by EWG yet, to be handled by the Reflection Study Group (SG7).
</p>
<p>In Chicago 2013, EWG decided to let SG7 handle this.</p>
<hr>
<h3><a name="24"></a>24.
N3441 Call Stack Utilities and std::exception Extension Proposal
</h3>
<p><b>Section:</b> 18.8 [support.exception] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Aurelian Melinte <b>Opened:</b> 2012-09-20 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3441.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3441.html</a>
<hr>
<h3><a name="26"></a>26.
N3538, N3445 Pass by Const Reference or Value
</h3>
<p><b>Section:</b> 8.3.5 [dcl.fct] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Lawrence Crowl <b>Opened:</b> 2012-09-23 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3445.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3445.html</a>
</p>
<p>
<a href="http://open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3538.html">http://open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3538.html</a>
</p>
<p>
Deemed post-C++14 material in Chicago 2013.
</p>
<hr>
<h3><a name="28"></a>28.
N3449 Open and Efficient Type Switch for C++
</h3>
<p><b>Section:</b> 5.2.7 [expr.dynamic.cast] <b>Status:</b> <a href="ewg-active.html#New">New</a>
<b>Submitter:</b> Bjarne Stroustrup <b>Opened:</b> 2012-09-23 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3449.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3449.pdf</a>
</p>
<p>
Deemed post-C++14 material in Chicago 2013.
</p>
<hr>
<h3><a name="29"></a>29.
N3329 Proposal: static if declaration
</h3>
<p><b>Section:</b> 20.9 [meta] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Herb Sutter <b>Opened:</b> 2012-01-10 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#meta">active issues</a> in [meta].</p>
<p><b>View all other</b> <a href="ewg-index.html#meta">issues</a> in [meta].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3329.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3329.pdf</a>
<p>
Reviewed by EWG in Portland 2012, deemed to be handled by the Concepts Study Group (SG8).
</p>
<p>
Deemed post-C++14 material in Chicago 2013. SG8 isn't including it in their
scope for the near future. Voutilainen is planning to write a simplified
proposal for C++17.
</p>
<hr>
<h3><a name="30"></a>30.
[tiny] Efficient/Flexible Access to Argument Packs
</h3>
<p><b>Section:</b> 14.5.3 [temp.variadic] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Dave Abrahams <b>Opened:</b> 2012-10-16 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
There are lots of very basic manipulations that are either really hard
or impossible to do with argument packs unless you use something that
causes a big recursive template instantiation, which is expensive at
compile-time and can cause bad error messages. I want to be able to
index argument packs with integral constant expressions, "take" or
"drop" the first N elements of the pack, etc.
</p>
<p>
In Bristol 2013: N3493 may solve parts of the problem. The submitter is encouraged to write a paper, and practical examples are desirable.
</p>
<p>N3761 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3761.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3761.html</a> seems related.
</p>
<hr>
<h3><a name="34"></a>34.
[tiny] Defining hash functions for composite user-defined types is annoying
</h3>
<p><b>Section:</b> 17.6.3.4 [hash.requirements] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Matt Austern <b>Opened:</b> 2012-10-23 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
We have a hash function for built-in types and for some standard library types, but we don't have automatically generated hash<> specializations for user-defined types like
<pre>
struct my_type {
int x;
std::string y;
vector<int> z;
};
</pre>
Defining a good and efficient hash function for composite types takes a fair amount of work. One consequence is that there are a lot of user-defined types with bad hash functions floating around.
One possibility is automatically generating hash<> specializations, but that's tricky. A simpler possibility is providing tools that make it easier for users to do the right thing.
</p>
<p>
Bristol 2013: Austern explained that he didn't envision syntax to automate the generation of hash operations but thought that this could potentially be solved by a library. Stroustrup and Austern thought that reflection would be another way to solve this. Van Winkel thought that for the generation of such things, it's perhaps desirable that they aren't generated by default but can be generated on demand when a user-defined type requests such generation. The guidance of the EWG is to propose a solution that handles equality operators and other such things in a more general manner.
</p>
<p>
EWG expressed long-term interest in this idea in Chicago 2013 for post-C++14.
Papers welcome.
</p>
<hr>
<h3><a name="35"></a>35.
[tiny] Some concise way to generate a unique, unused variable name
</h3>
<p><b>Section:</b> 3.4 [basic.lookup] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2012-10-24 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Sometimes we want to define a variable that's unused except for its
constructor and destructor. lock_guard<mutex> and ScopeGuard are
decent examples of this. In C++11, we have to manually name the
variable something unique. Sometimes we use _some_name_##__LINE__
(suitably wrapped so the concatenation happens after expanding
__LINE__) to try to generate unique names automatically, and gcc/clang
have an extension _some_name_##__COUNTER__
<p>
<a href="http://gcc.gnu.org/onlinedocs/gcc-4.7.2/cpp/Common-Predefined-Macros.html">http://gcc.gnu.org/onlinedocs/gcc-4.7.2/cpp/Common-Predefined-Macros.html</a>
</p>
to allow multiple such variables on the same line. These are pretty
verbose and not convenient for casual use.
Haskell allows _ (underscore) to stand in for a variable that's not
going to be used. Googlemock defines testing::_ to mean "don't care"
as an argument, which is similar but not identical.
</p>
<p>
Bristol 2013: Stroustrup wondered how unique the name needs to be, and wondered whether parallel builds would have problems ensuring the uniqueness. Naumann pointed out that having an unnamed variable is useful also for cases where you don't want the variable's address to be taken etc. Stroustrup and Van Winkel said this is not tiny, and a proper paper is necessary for this issue.
</p>
<p>
Chicago 2013: Deemed not as C++14 material, Yasskin or someone else
invited to write a paper, straw polls in favor of the feature. Things
to consider in the paper: Consider double underscore "__". Can
it be used only in local scope? For class members? For globals?
</p>
<hr>
<h3><a name="40"></a>40.
[tiny] Relax the allocator requirements on vector so that the small object optimization is allowed
</h3>
<p><b>Section:</b> 23.3.6 [vector] <b>Status:</b> <a href="ewg-active.html#Ready">Ready</a>
<b>Submitter:</b> Nevin Liber <b>Opened:</b> 2012-11-27 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Ready">Ready</a> status.</p>
<p><b>Discussion:</b></p>
<p>
I'd like it to be possible to use the small object optimization (embedding up to a fixed number of objects inside the allocator itself) inside a vector.
</p>
<p>
Bristol 2013: Designated for LEWG.
</p>
<hr>
<h3><a name="41"></a>41.
[tiny] In-class explicit specializations forbidden but not partial specializations
</h3>
<p><b>Section:</b> 14.7.3 [temp.expl.spec] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Faisal Vali <b>Opened:</b> 2012-10-27 <b>Last modified:</b> 2014-01-16</p>
<p><b>View other</b> <a href="ewg-index-open.html#temp.expl.spec">active issues</a> in [temp.expl.spec].</p>
<p><b>View all other</b> <a href="ewg-index.html#temp.expl.spec">issues</a> in [temp.expl.spec].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
I had submitted a DR (727) about this in October 2008 - and it was
classified as an extension - I wonder if Spertus' DR (1077) that was
also classified as an extension should be considered along with this
one.
14.7.3 [temp.expl.spec] paragraph 2 requires that explicit
specializations of member templates be declared in namespace scope,
not in the class definition. This restriction does not apply to
partial specializations of member templates; that is,
<pre>
struct A {
template<class T> struct B;
template <class T> struct B<T*> { }; // well-formed
template <> struct B<int*> { }; // ill-formed
};
</pre>
There does not seem to be a good reason for this inconsistency.
</p>
<p>
Bristol 2013: Defer to Core, with the guidance to reopen the DR mentioned and remove the restriction.
</p>
<p>
Before this can go over to Core, it needs wording. It's likely that it
needs a paper. Vali should create either the wording or the paper.
</p>
<hr>
<h3><a name="42"></a>42.
[tiny] basic_string(const charT*, size_type, const Allocator&) requires clause too restrictive
</h3>
<p><b>Section:</b> 21.4.2 [string.cons] <b>Status:</b> <a href="ewg-active.html#Ready">Ready</a>
<b>Submitter:</b> Nevin Liber <b>Opened:</b> 2012-12-19 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Ready">Ready</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In n3485 21.4.2p6 (basic_string constructors and assignment operators), we have:
<pre>
basic_string(const charT* s, size_type n,
const Allocator& a = Allocator());
Requires: s shall not be a null pointer and n < npos.
</pre>
That requires clause is too restrictive; s can be a null pointer when n==0.
A (simplified) use case I have seen:
<pre>
std::string StringFromVector(std::vector<char> const& vc)
{ return std::string(vc.data(), vc.size()); }
</pre>
Since a conforming implementation can return a null pointer for vc.data() when vc.size() == 0. I don't see any reason to disallow this construct, especially since it takes a Standards expert to see that this is possibly illegal, but not std::string(vc.data(), vc.data() + vc.size()).
</p>
This is likely to go onto the LEWG's plate.
<p>
Bristol 2013: Defer to LEWG.
</p>
<p><b>Wording available:</b></p>
<pre>
Requires: n < npos and either s shall not be a null pointer or n == 0.
</pre>
<hr>
<h3><a name="43"></a>43.
[tiny] simultaneous iteration with new-style for syntax
</h3>
<p><b>Section:</b> 6.5.4 [stmt.ranged] <b>Status:</b> <a href="ewg-active.html#Open">Open</a>
<b>Submitter:</b> Gabriel Dos Reis <b>Opened:</b> 2013-01-12 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Open">Open</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The new-style 'for' syntax allows us to dispense with administrative
iterator declarations when iterating over a single seuqence.
The burden and noise remain, however, when iterating over two or more
sequences simultaenously. We should extend the syntax to allow that.
E.g. one should be able to write:
<pre>
for (auto& x : v; auto& y : w)
a = combine(v, w, a);
</pre>
instead of the noisier
<pre>
auto p1 = v.begin();
auto q1 = v.end();
auto p2 = w.begin();
auto q2 = w.end();
while (p1 < q1 and p2 < q2) {
a = combine(*p1, *p2, a);
++p1;
++p2;
}
</pre>
</p>
<p>
Bristol 2013: Submitter is encouraged to write a paper.
</p>
<p>EWG expressed reiterated interest in Chicago 2013 for this idea, deeming
it post-C++14 material.</p>
<hr>
<h3><a name="44"></a>44.
[tiny] variadic bind
</h3>
<p><b>Section:</b> 20.8.9 [bind] <b>Status:</b> <a href="ewg-active.html#Ready">Ready</a>
<b>Submitter:</b> Chris Jefferson <b>Opened:</b> 2013-01-25 <b>Last modified:</b> 2013-10-14</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Ready">Ready</a> status.</p>
<p><b>Discussion:</b></p>
<p>
As more variadic functions work their way into my C++ code, I'm getting increasingly annoyed that there isn't a variadic bind.
There is a tiny bit of annoyance on exactly what to use. There seems to me to be 2 sensible choices (other people may have others)
<pre>
1) _args : Use all otherwise unnamed arguments.
2) _3onwards : All arguments from the 3rd onwards.
</pre>
I haven't personally found a need for multiple ranges of variadic arguments, or more complicated chopping (such as getting the last few arguments), and I'd want to hopefully keep this simple if possible!
</p>
<p>
Bristol 2013: Defer to LEWG.
</p>
<hr>
<h3><a name="45"></a>45.
[tiny] Type Trait is_range<T>
</h3>
<p><b>Section:</b> 20.9.4.3 [meta.unary.prop] <b>Status:</b> <a href="ewg-active.html#Ready">Ready</a>
<b>Submitter:</b> Nevin Liber <b>Opened:</b> 2013-02-05 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#meta.unary.prop">active issues</a> in [meta.unary.prop].</p>
<p><b>View all other</b> <a href="ewg-index.html#meta.unary.prop">issues</a> in [meta.unary.prop].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Ready">Ready</a> status.</p>
<p><b>Discussion:</b></p>
<p>
I'd like to have an is_range<T, R = void> type trait, which derives from true_type if and only if T can be used in range-based for, and *__begin is convertible to R (where R == void means don't bother checking this condition).
</p>
<p>
Bristol 2013: Submitter is encouraged to proceed and present to LWG. Apparently LEWG doesn't handle these.
</p>
<hr>
<h3><a name="46"></a>46.
[tiny] Type Trait is_final<T>
</h3>
<p><b>Section:</b> 20.9.4.3 [meta.unary.prop] <b>Status:</b> <a href="ewg-active.html#Ready">Ready</a>
<b>Submitter:</b> Nevin Liber <b>Opened:</b> 2013-02-05 <b>Last modified:</b> 2013-10-14</p>
<p><b>View other</b> <a href="ewg-index-open.html#meta.unary.prop">active issues</a> in [meta.unary.prop].</p>
<p><b>View all other</b> <a href="ewg-index.html#meta.unary.prop">issues</a> in [meta.unary.prop].</p>
<p><b>View all issues with</b> <a href="ewg-status.html#Ready">Ready</a> status.</p>
<p><b>Discussion:</b></p>
<p>
I'd like to have an is_final<T> type trait, which is true if and only if T is a final type.
</p>
<p>
Bristol 2013: Submitter is encouraged to proceed and present to LWG. Apparently LEWG doesn't handle these.
</p>
<hr>
<h3><a name="48"></a>48.
N3730 Specializations and namespaces (was "Specializing templates in different namespaces" before the paper)
</h3>