+2001-09-25 Phil Edwards <pme@gcc.gnu.org>
+
+ * docs/html/20_util/howto.html: Add anchor name.
+ * docs/html/23_containers/howto.html: Line wrapping, another link.
+ * docs/html/25_algorithms/howto.html: Another note.
+
+ * docs/html/ext/howto.html: Link to SGI extensions. List DRs and
+ link to them...
+ * docs/html/ext/lwg-active.html: ...in this new file (from R19),
+ * docs/html/ext/lwg-defects.html: and this new file (from R19).
+ * docs/html/ext/sgiexts.html: New file. Mention SGI extensions
+ carried over to libstdc++-v3.
+ * docs/html/faq/index.html: Link to SGI extensions. Mention the
+ "missing .." pseudobug.
+ * docs/html/faq/index.txt: Regenerate.
+
+ * include/bits/ios_base.h: DR-related comment cleanup.
+ * include/bits/istream.tcc: Likewise.
+ * include/bits/locale_facets.h: Likewise.
+ * include/bits/locale_facets.tcc: Likewise.
+ * include/bits/ostream.tcc: Likewise.
+ * include/bits/std_bitset.h: Likewise.
+ * include/bits/std_iosfwd.h: Likewise.
+ * include/bits/std_istream.h: Likewise.
+ * include/bits/std_ostream.h: Likewise.
+ * include/bits/std_streambuf.h: Likewise.
+ * include/bits/stl_pair.h: Likewise.
+ * include/bits/streambuf_iterator.h: Likewise.
+
+ * include/bits/std_map.h: Remove unused header inclusion guard
+ _CPP_BITS_STL_TREE_H from around bits/stl_tree.h.
+ * include/bits/std_set.h: Likewise.
+
+ * include/bits/stl_function.h: Doxygen markup.
+ * docs/doxygen/doxygroups.cc: New file, specifying module grouping.
+ * libsupc++/typeinfo: Doxygen markup tweak.
+
2001-09-20 Scott Johnston <scott@accom.com>
Peter Schmid <schmid@snake.iap.physik.tu-darmstadt.de>
--- /dev/null
+
+// This just provides documentation for stuff that doesn't need to be in the
+// source headers themselves. It is a ".cc" file for the sole cheesy reason
+// that it triggers many different text editors into doing Nice Things when
+// typing comments. However, it is mentioned nowhere except the *cfg.in files.
+
+/** @addtogroup SGIextensions
+ *
+ * Because libstdc++-v3 based its implementation of the STL subsections of
+ * the library on the SGI 3.3 implementation, we inherited their extensions
+ * as well.
+ *
+ * They are additionally documented in the
+ * <a href="http://gcc.gnu.org/onlinedocs/libstdc++/documentation.html">
+ * online documentation</a>, a copy of which is also shipped with the
+ * library source code (in .../docs/html/documentation.html). You can also
+ * read the documentation <a href="http://www.sgi.com/tech/stl/">on SGI's
+ * site</a>, which is still running even though the code is not maintained.
+ *
+ * <strong>NB</strong> that the following notes are pulled from various
+ * comments all over the place, so they may seem stilted.
+ * <hr>
+*/
+
<meta NAME="GENERATOR" CONTENT="vi and eight fingers">
<title>libstdc++-v3 HOWTO: Chapter 20</title>
<link REL=StyleSheet HREF="../lib3styles.css">
-<!-- $Id: howto.html,v 1.4 2001/05/30 21:55:00 pme Exp $ -->
+<!-- $Id: howto.html,v 1.5 2001/09/17 23:24:39 pme Exp $ -->
</head>
<body>
<code>operator==</code> functions (for types like MyClass) or builtin
comparisons (for types like int, char, etc).
</p>
+ <a name="pairlt">
<p>The less-than operator is a bit odd the first time you see it. It
is defined as evaluating to:
<PRE>
The other operators are not defined using the <code>rel_ops</code>
functions above, but their semantics are the same.
</p>
+ </a>
<p>Finally, there is a template function called <code>make_pair</code>
that takes two references-to-const objects and returns an
instance of a pair instantiated on their respective types:
<P CLASS="fineprint"><em>
Comments and suggestions are welcome, and may be sent to
<a href="mailto:libstdc++@gcc.gnu.org">the mailing list</a>.
-<br> $Id: howto.html,v 1.4 2001/05/30 21:55:00 pme Exp $
+<br> $Id: howto.html,v 1.5 2001/09/17 23:24:39 pme Exp $
</em></p>
<meta NAME="GENERATOR" CONTENT="vi and eight fingers">
<title>libstdc++-v3 HOWTO: Chapter 23</title>
<link REL=StyleSheet HREF="../lib3styles.css">
-<!-- $Id: howto.html,v 1.8 2001/09/15 00:41:11 pme Exp $ -->
+<!-- $Id: howto.html,v 1.9 2001/09/17 23:24:39 pme Exp $ -->
</head>
<body>
<p><B>A container<bool>. </B> The Committee made provision
for the space savings possible with that (N/8) usage previously mentioned,
so that you don't have to do wasteful things like
- <code>Container<char></code> or <code>Container<short int></code>.
+ <code>Container<char></code> or
+ <code>Container<short int></code>.
Specifically, <code>vector<bool></code> is required to be
specialized for that space savings.
</p>
<p><B>Extremely weird solutions. </B> If you have access to
the compiler and linker at runtime, you can do something insane, like
figuring out just how many bits you need, then writing a temporary
- source code file. That file contains an instantiation of <code>bitset</code>
+ source code file. That file contains an instantiation of
+ <code>bitset</code>
for the required number of bits, inside some wrapper functions with
unchanging signatures. Have your program then call the
compiler on that file using Position Independant Code, then open the
newly-created object file and load those wrapper functions. You'll have
- an instantiation of <code>bitset<N></code> for the exact <code>N</code>
+ an instantiation of <code>bitset<N></code> for the exact
+ <code>N</code>
that you need at the time. Don't forget to delete the temporary files.
(Yes, this <em>can</em> be, and <em>has been</em>, done.)
</p>
along the lines of the third category, the author would love to hear
from you...
</p>
+ <p>Also note that the implementation of bitset used in libstdc++-v3 has
+ <a href="../ext/sgiexts.html#ch23">some extensions</a>.
+ </p>
<p>Return <a href="#top">to top of page</a> or
<a href="../faq/index.html">to the FAQ</a>.
</p>
<P CLASS="fineprint"><em>
Comments and suggestions are welcome, and may be sent to
<a href="mailto:libstdc++@gcc.gnu.org">the mailing list</a>.
-<br> $Id: howto.html,v 1.8 2001/09/15 00:41:11 pme Exp $
+<br> $Id: howto.html,v 1.9 2001/09/17 23:24:39 pme Exp $
</em></p>
<meta NAME="GENERATOR" CONTENT="vi and eight fingers">
<title>libstdc++-v3 HOWTO: Chapter 25</title>
<link REL=StyleSheet HREF="../lib3styles.css">
-<!-- $Id: howto.html,v 1.4 2001/09/15 00:41:11 pme Exp $ -->
+<!-- $Id: howto.html,v 1.5 2001/09/17 23:24:39 pme Exp $ -->
</head>
<body>
<h1>Contents</h1>
<ul>
<li><a href="#1">Prerequisites</a>
- <li><a href="#2">Topic</a>
+ <li><a href="#2">Special <code>swap</code>s</a>
</ul>
<hr>
</p>
<hr>
-<h2><a name="2">Topic</a></h2>
- <p>Blah.
+<h2><a name="2">Special <code>swap</code>s</a></h2>
+ <p>If you call <code> std::swap(x,y); </code> where x and y are standard
+ containers, then the call will automatically be replaced by a call to
+ <code> x.swap(y); </code> instead.
+ </p>
+ <p>This allows member functions of each container class to take over, and
+ containers' swap functions should have O(1) complexity according to
+ the standard. (And while "should" allows implementations to
+ behave otherwise and remain compliant, this implementation does in
+ fact use constant-time swaps.) This should not be surprising, since
+ for two containers of the same type to swap contents, only some
+ internal pointers to storage need to be exchanged.
</p>
<p>Return <a href="#top">to top of page</a> or
<a href="../faq/index.html">to the FAQ</a>.
<P CLASS="fineprint"><em>
Comments and suggestions are welcome, and may be sent to
<a href="mailto:libstdc++@gcc.gnu.org">the mailing list</a>.
-<br> $Id: howto.html,v 1.4 2001/09/15 00:41:11 pme Exp $
+<br> $Id: howto.html,v 1.5 2001/09/17 23:24:39 pme Exp $
</em></p>
<meta NAME="GENERATOR" CONTENT="vi and eight fingers">
<title>libstdc++-v3 HOWTO: Extensions</title>
<link REL=StyleSheet HREF="../lib3styles.css">
-<!-- $Id: howto.html,v 1.5 2001/05/30 21:55:04 pme Exp $ -->
+<!-- $Id: howto.html,v 1.6 2001/09/17 23:24:40 pme Exp $ -->
</head>
<body>
<h1>Contents</h1>
<ul>
<li><a href="#1">Ropes and trees and hashes, oh my!</a>
- <li><a href="#2">Added members</a>
+ <li><a href="#2">Added members and types</a>
<li><a href="#3">Allocators</a>
<li><a href="#4">Compile-time checks</a>
+ <li><a href="#5">LWG Issues</a>
</ul>
<hr>
</p>
<hr>
-<h2><a name="2">Added members</a></h2>
+<h2><a name="2">Added members and types</a></h2>
<p>Some of the classes in the Standard Library have additional
- publicly-available members. Of those, some are intended purely for
- the implementors, for example, additional typedefs. Those won't be
- described here (or anywhere else). This list will grow slowly, since
- we expect it to be rare -- most extensions will be self-contained.
+ publicly-available members, and some classes are themselves not in
+ the standard. Of those, some are intended purely for the implementors,
+ for example, additional typedefs. Those won't be described here
+ (or anywhere else).
</p>
<p>
<ul>
+ <li>The extensions added by SGI are so numerous that they have
+ <a href="sgiexts.html">their own page</a>. Since the SGI STL is no
+ longer actively maintained, we will try and keep this code working
+ ourselves.
<li><code>filebuf</code>s have another ctor with this signature:<br>
<code>basic_filebuf(__c_file_type*, ios_base::openmode, int_type);</code>
<br>This comes in very handy in a number of places, such as
<a href="../faq/index.html">to the FAQ</a>.
</p>
+<hr>
+<h2><a name="5">LWG Issues</a></h2>
+ <p>Everybody's got issues. Even the C++ Standard Library.
+ </p>
+ <p>The Library Working Group, or LWG, is the ISO subcommittee responsible
+ for making changes to the library. They periodically publish an
+ Issues List containing problems and possible solutions. As they reach
+ a consensus on proposed solutions, we often incorporate the solution
+ into libstdc++-v3.
+ </p>
+ <p>Here are the issues which have resulted in code changes to the library.
+ The links are to the specific defect reports from a <strong>partial
+ copy </strong> of the
+ Issues List. You can read the full version online at the ISO C++
+ Committee homepage, linked to on the GCC "Readings" page. If
+ you spend a lot of time reading the issues, we recommend downloading
+ the ZIP file and reading them locally.
+ </p>
+ <p>(NB: <strong>partial copy</strong> means that not all links within
+ the lwg-*.html pages will work.
+ Specifically, links to defect reports that have not been accorded full
+ DR status will probably break. Rather than trying to mirror the
+ entire issues list on our overworked web server, we recommend you go
+ to the LWG homepage instead.)
+ </p>
+ <p>
+ If a DR is not listed here, we may simply not have gotten to it yet;
+ feel free to submit a patch. Search the include/bits and src
+ directories for appearances of _GLIBCPP_RESOLVE_LIB_DEFECTS for
+ examples of style. Note that we usually do not make changes to the code
+ until an issue has reached <a href="lwg-active.html#DR">DR</a> status.
+ </p>
+ <p><dl>
+<!-- FIXME: locale_facets.h/tcc has a fix for get/num_get which I can't ID. -->
+
+ <dt><a href="lwg-defects.html#5">5</a>:
+ <em>string::compare specification questionable</em>
+ <dd>This should be two overloaded functions rather than a single function.
+
+ <dt><a href="lwg-defects.html#17">17</a>:
+ <em>Bad bool parsing</em>
+ <dd>Apparently extracting Boolean values was messed up...
+
+ <dt><a href="lwg-defects.html#25">25</a>:
+ <em>String operator<< uses width() value wrong</em>
+ <dd>Padding issues.
+
+ <dt><a href="lwg-defects.html#48">48</a>:
+ <em>Use of non-existent exception constructor</em>
+ <dd>An instance of <code>ios_base::failure</code> is constructed instead.
+
+ <dt><a href="lwg-defects.html#49">49</a>:
+ <em>Underspecification of ios_base::sync_with_stdio</em>
+ <dd>The return type is the <em>previous</em> state of synchronization.
+
+ <dt><a href="lwg-defects.html#50">50</a>:
+ <em>Copy constructor and assignment operator of ios_base</em>
+ <dd>These members functions are declared <code>private</code> and are
+ thus inaccessible. Specifying the correct semantics of
+ "copying stream state" was deemed too complicated.
+
+ <dt><a href="lwg-defects.html#68">68</a>:
+ <em>Extractors for char* should store null at end</em>
+ <dd>And they do now. An editing glitch in the last item in the list of
+ [27.6.1.2.3]/7.
+
+ <dt><a href="lwg-defects.html#74">74</a>:
+ <em>Garbled text for codecvt::do_max_length</em>
+ <dd>The text of the standard was gibberish. Typos gone rampant.
+
+ <dt><a href="lwg-defects.html#83">83</a>:
+ <em>string::npos vs. string::max_size()</em>
+ <dd>Safety checks on the size of the string should test against
+ <code>max_size()</code> rather than <code>npos</code>.
+ <dt><a href="lwg-defects.html#109">109</a>:
+ <em>Missing binders for non-const sequence elements</em>
+ <dd>The <code>binder1st</code> and <code>binder2nd</code> didn't have an
+ <code>operator()</code> taking a non-const parameter.
+
+ <dt><a href="lwg-defects.html#110">110</a>:
+ <em>istreambuf_iterator::equal not const</em>
+ <dd>This was not a const member function. Note that the DR says to
+ replace the function with a const one; we have instead provided an
+ overloaded version with identical contents.
+
+ <dt><a href="lwg-defects.html#129">129</a>:
+ <em>Need error indication from seekp() and seekg()</em>
+ <dd>These functions set <code>failbit</code> on error now.
+
+ <dt><a href="lwg-defects.html#136">136</a>:
+ <em>seekp, seekg setting wrong streams?</em>
+ <dd><code>seekp</code> should only set the output stream, and
+ <code>seekg</code> should only set the input stream.
+
+<!--<dt><a href="lwg-defects.html#159">159</a>:
+ <em>Strange use of underflow()</em>
+ <dd>In fstream.tcc, the basic_filebuf<>::showmanyc() function
+ should probably not be calling <code>underflow()</code>.-->
+
+ <dt><a href="lwg-active.html#167">167</a>:
+ <em>Improper use of traits_type::length()</em>
+ <dd><code>op<<</code> with a <code>const char*</code> was
+ calculating an incorrect number of characters to write.
+
+ <dt><a href="lwg-defects.html#181">181</a>:
+ <em>make_pair() unintended behavior</em>
+ <dd>This function used to take its arguments as reference-to-const, now
+ it copies them (pass by value).
+
+ <dt><a href="lwg-defects.html#195">195</a>:
+ <em>Should basic_istream::sentry's constructor ever set eofbit?</em>
+ <dd>Yes, it can, specifically if EOF is reached while skipping whitespace.
+
+ <dt><a href="lwg-defects.html#211">211</a>:
+ <em>operator>>(istream&, string&) doesn't set failbit</em>
+ <dd>If nothing is extracted into the string, <code>op>></code> now
+ sets <code>failbit</code> (which can cause an exception, etc, etc).
+
+ <dt><a href="lwg-defects.html#214">214</a>:
+ <em>set::find() missing const overload</em>
+ <dd>Both <code>set</code> and <code>multiset</code> were missing
+ overloaded find, lower_bound, upper_bound, and equal_range functions
+ for const instances.
+
+ <dt><a href="lwg-defects.html#251">251</a>:
+ <em>basic_stringbuf missing allocator_type</em>
+ <dd>This nested typdef was originally not specified.
+
+ <dt><a href="lwg-defects.html#265">265</a>:
+ <em>std::pair::pair() effects overly restrictive</em>
+ <dd>The default ctor would build its members from copies of temporaries;
+ now it simply uses their respective default ctors.
+
+<!--
+ <dt><a href="lwg-defects.html#"></a>:
+ <em></em>
+ <dd>
+
+-->
+ </dl></p>
+ <p>Return <a href="#top">to top of page</a> or
+ <a href="../faq/index.html">to the FAQ</a>.
<!-- ####################################################### -->
<P CLASS="fineprint"><em>
Comments and suggestions are welcome, and may be sent to
<a href="mailto:libstdc++@gcc.gnu.org">the mailing list</a>.
-<br> $Id: howto.html,v 1.5 2001/05/30 21:55:04 pme Exp $
+<br> $Id: howto.html,v 1.6 2001/09/17 23:24:40 pme Exp $
</em></p>
--- /dev/null
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head><title>C++ Standard Library Active Issues List</title></head>
+<body bgcolor="#ffffff" text="#000000">
+<table>
+<tr>
+<td align="left">Doc. no.</td>
+<td align="left">J16/01-0031 = WG21 N1317</td>
+</tr>
+<tr>
+<td align="left">Date:</td>
+<td align="left">11 Sep 2001</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">Matt Austern <austern@research.att.com></td>
+</tr>
+</table>
+<h1>C++ Standard Library Active Issues List (Revision 19)</h1>
+ <p>Reference ISO/IEC IS 14882:1998(E)</p>
+ <p>Also see:</p>
+ <ul>
+ <li>
+<a href="lwg-toc.html">Table of Contents</a> for all library issues.</li>
+ <li>
+<a href="lwg-index.html">Index by Section</a> for all library issues.</li>
+ <li>
+<a href="lwg-status.html">Index by Status</a> for all library issues.</li>
+ <li><a href="lwg-defects.html">Library Defect Reports List</a></li>
+ <li><a href="lwg-closed.html">Library Closed Issues List</a></li>
+ </ul>
+ <p>The purpose of this document is to record the status of issues
+ which have come before the Library Working Group (LWG) of the ANSI
+ (J16) and ISO (WG21) C++ Standards Committee. Issues represent
+ potential defects in the ISO/IEC IS 14882:1998(E) document. Issues
+ are not to be used to request new features or other extensions. </p>
+
+ <p>This document contains only library issues which are actively being
+ considered by the Library Working Group. That is, issues which have a
+ status of <a href="lwg-active.html#New">New</a>, <a href="lwg-active.html#Open">Open</a>,
+ <a href="lwg-active.html#Ready">Ready</a>, and <a href="lwg-active.html#Review">Review</a>. See
+ <a href="lwg-defects.html">Library Defect Reports List</a> for issues considered defects and
+ <a href="lwg-closed.html">Library Closed Issues List</a> for issues considered closed.</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 is in an experimental format designed for both
+ viewing via a world-wide web browser and hard-copy printing. It
+ is available as an HTML file for browsing or PDF file for
+ printing.</p>
+
+ <p>Prior to Revision 14, library issues lists existed in two slightly
+ different versions; a Committee Version and a Public
+ Version. Beginning with Revision 14 the two versions were combined
+ into a single version.</p>
+
+ <p>This document includes <i>[bracketed italicized notes]</i> as a
+ reminder to the LWG 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 LWG 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.dkuug.dk/jtc1/sc22/wg21">http://www.dkuug.dk/jtc1/sc22/wg21</a>.
+ Requests for further information about this document should include
+ the document number above, reference ISO/IEC 14882:1998(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 C++ FAQ at <a href="http://www.research.att.com/~austern/csc/faq.html">http://www.research.att.com/~austern/csc/faq.html</a>.
+ Public discussion of C++ Standard related issues occurs on <a href="news:comp.std.c++">news:comp.std.c++</a>.
+ </p>
+
+ <p>For committee members, files available on the committee's private
+ web site include the HTML version of the Standard itself. HTML
+ hyperlinks from this issues list to those files will only work for
+ committee members who have downloaded them into the same disk
+ directory as the issues list files. </p>
+<h2>Revision History</h2>
+<ul>
+<li>R19:
+Pre-Redmond mailing. Added new issues
+<a href="lwg-active.html#323">323</a>-<a href="lwg-active.html#335">335</a>.
+</li>
+<li>R18:
+Post-Copenhagen mailing; reflects actions taken in Copenhagen.
+Added new issues <a href="lwg-active.html#312">312</a>-<a href="lwg-active.html#317">317</a>, and discussed
+new issues <a href="lwg-active.html#271">271</a>-<a href="lwg-closed.html#314">314</a>.
+
+Changed status of issues
+<a href="lwg-defects.html#103">103</a> <a href="lwg-defects.html#118">118</a> <a href="lwg-defects.html#136">136</a> <a href="lwg-defects.html#153">153</a>
+<a href="lwg-defects.html#165">165</a> <a href="lwg-defects.html#171">171</a> <a href="lwg-defects.html#183">183</a> <a href="lwg-defects.html#184">184</a>
+<a href="lwg-defects.html#185">185</a> <a href="lwg-defects.html#186">186</a> <a href="lwg-defects.html#214">214</a> <a href="lwg-defects.html#221">221</a>
+<a href="lwg-defects.html#234">234</a> <a href="lwg-defects.html#237">237</a> <a href="lwg-defects.html#243">243</a> <a href="lwg-defects.html#248">248</a>
+<a href="lwg-defects.html#251">251</a> <a href="lwg-defects.html#252">252</a> <a href="lwg-defects.html#256">256</a> <a href="lwg-defects.html#260">260</a>
+<a href="lwg-defects.html#261">261</a> <a href="lwg-defects.html#262">262</a> <a href="lwg-defects.html#263">263</a> <a href="lwg-defects.html#265">265</a>
+<a href="lwg-defects.html#268">268</a>
+to DR.
+
+Changed status of issues
+<a href="lwg-active.html#49">49</a> <a href="lwg-active.html#109">109</a> <a href="lwg-active.html#117">117</a> <a href="lwg-active.html#182">182</a>
+<a href="lwg-active.html#228">228</a> <a href="lwg-active.html#230">230</a> <a href="lwg-active.html#232">232</a> <a href="lwg-active.html#235">235</a>
+<a href="lwg-active.html#238">238</a> <a href="lwg-active.html#241">241</a> <a href="lwg-active.html#242">242</a> <a href="lwg-active.html#250">250</a>
+<a href="lwg-active.html#259">259</a> <a href="lwg-active.html#264">264</a> <a href="lwg-active.html#266">266</a> <a href="lwg-active.html#267">267</a>
+<a href="lwg-active.html#271">271</a> <a href="lwg-active.html#272">272</a> <a href="lwg-active.html#273">273</a> <a href="lwg-active.html#275">275</a>
+<a href="lwg-active.html#281">281</a> <a href="lwg-active.html#284">284</a> <a href="lwg-active.html#285">285</a> <a href="lwg-active.html#286">286</a>
+<a href="lwg-active.html#288">288</a> <a href="lwg-active.html#292">292</a> <a href="lwg-active.html#295">295</a> <a href="lwg-active.html#297">297</a>
+<a href="lwg-active.html#298">298</a> <a href="lwg-active.html#301">301</a> <a href="lwg-active.html#303">303</a> <a href="lwg-active.html#306">306</a>
+<a href="lwg-active.html#307">307</a> <a href="lwg-active.html#308">308</a> <a href="lwg-active.html#312">312</a>
+to Ready.
+
+Closed issues
+<a href="lwg-closed.html#111">111</a> <a href="lwg-closed.html#277">277</a> <a href="lwg-closed.html#279">279</a> <a href="lwg-closed.html#287">287</a>
+<a href="lwg-closed.html#289">289</a> <a href="lwg-closed.html#293">293</a> <a href="lwg-closed.html#302">302</a> <a href="lwg-closed.html#313">313</a>
+<a href="lwg-closed.html#314">314</a>
+as NAD.
+
+</li>
+<li>R17:
+Pre-Copenhagen mailing. Converted issues list to XML. Added proposed
+resolutions for issues <a href="lwg-active.html#49">49</a>, <a href="lwg-active.html#76">76</a>, <a href="lwg-active.html#91">91</a>, <a href="lwg-active.html#235">235</a>, <a href="lwg-active.html#250">250</a>, <a href="lwg-active.html#267">267</a>.
+Added new issues <a href="lwg-active.html#278">278</a>-<a href="lwg-active.html#311">311</a>.
+</li>
+<li>R16:
+post-Toronto mailing; reflects actions taken in Toronto. Added new
+issues <a href="lwg-defects.html#265">265</a>-<a href="lwg-closed.html#277">277</a>. Changed status of issues
+<a href="lwg-defects.html#3">3</a>, <a href="lwg-defects.html#8">8</a>, <a href="lwg-defects.html#9">9</a>, <a href="lwg-defects.html#19">19</a>,
+<a href="lwg-defects.html#26">26</a>, <a href="lwg-defects.html#31">31</a>, <a href="lwg-defects.html#61">61</a>,
+<a href="lwg-defects.html#63">63</a>, <a href="lwg-defects.html#86">86</a>, <a href="lwg-defects.html#108">108</a>,
+<a href="lwg-defects.html#112">112</a>, <a href="lwg-defects.html#114">114</a>, <a href="lwg-defects.html#115">115</a>,
+<a href="lwg-defects.html#122">122</a>, <a href="lwg-defects.html#127">127</a>, <a href="lwg-defects.html#129">129</a>,
+<a href="lwg-defects.html#134">134</a>, <a href="lwg-defects.html#137">137</a>, <a href="lwg-defects.html#142">142</a>,
+<a href="lwg-defects.html#144">144</a>, <a href="lwg-defects.html#146">146</a>, <a href="lwg-defects.html#147">147</a>,
+<a href="lwg-defects.html#159">159</a>, <a href="lwg-defects.html#164">164</a>, <a href="lwg-defects.html#170">170</a>,
+<a href="lwg-defects.html#181">181</a>, <a href="lwg-defects.html#199">199</a>, <a href="lwg-defects.html#208">208</a>,
+<a href="lwg-defects.html#209">209</a>, <a href="lwg-defects.html#210">210</a>, <a href="lwg-defects.html#211">211</a>,
+<a href="lwg-defects.html#212">212</a>, <a href="lwg-defects.html#217">217</a>, <a href="lwg-defects.html#220">220</a>,
+<a href="lwg-defects.html#222">222</a>, <a href="lwg-defects.html#223">223</a>, <a href="lwg-defects.html#224">224</a>,
+<a href="lwg-defects.html#227">227</a> to "DR". Reopened issue <a href="lwg-active.html#23">23</a>. Reopened
+issue <a href="lwg-active.html#187">187</a>. Changed issues <a href="lwg-closed.html#2">2</a> and
+<a href="lwg-closed.html#4">4</a> to NAD. Fixed a typo in issue <a href="lwg-defects.html#17">17</a>. Fixed
+issue <a href="lwg-defects.html#70">70</a>: signature should be changed both places it
+appears. Fixed issue <a href="lwg-defects.html#160">160</a>: previous version didn't fix
+the bug in enough places.
+</li>
+<li>R15:
+pre-Toronto mailing. Added issues
+<a href="lwg-active.html#233">233</a>-<a href="lwg-active.html#264">264</a>. Some small HTML formatting
+changes so that we pass Weblint tests.
+</li>
+<li>R14:
+post-Tokyo II mailing; reflects committee actions taken in
+Tokyo. Added issues <a href="lwg-active.html#228">228</a> to <a href="lwg-active.html#232">232</a>. (00-0019R1/N1242)
+</li>
+<li>R13:
+pre-Tokyo II updated: Added issues <a href="lwg-defects.html#212">212</a> to <a href="lwg-defects.html#227">227</a>.
+</li>
+<li>R12:
+pre-Tokyo II mailing: Added issues <a href="lwg-defects.html#199">199</a> to
+<a href="lwg-defects.html#211">211</a>. Added "and paragraph 5" to the proposed resolution
+of issue <a href="lwg-defects.html#29">29</a>. Add further rationale to issue
+<a href="lwg-closed.html#178">178</a>.
+</li>
+<li>R11:
+post-Kona mailing: Updated to reflect LWG and full committee actions
+in Kona (99-0048/N1224). Note changed resolution of issues
+<a href="lwg-closed.html#4">4</a> and <a href="lwg-defects.html#38">38</a>. Added issues <a href="lwg-closed.html#196">196</a>
+to <a href="lwg-active.html#198">198</a>. Closed issues list split into "defects" and
+"closed" documents. Changed the proposed resolution of issue
+<a href="lwg-closed.html#4">4</a> to NAD, and changed the wording of proposed resolution
+of issue <a href="lwg-defects.html#38">38</a>.
+</li>
+<li>R10:
+pre-Kona updated. Added proposed resolutions <a href="lwg-defects.html#83">83</a>,
+<a href="lwg-defects.html#86">86</a>, <a href="lwg-active.html#91">91</a>, <a href="lwg-active.html#92">92</a>,
+<a href="lwg-active.html#109">109</a>. Added issues <a href="lwg-closed.html#190">190</a> to
+<a href="lwg-defects.html#195">195</a>. (99-0033/D1209, 14 Oct 99)
+</li>
+<li>R9:
+pre-Kona mailing. Added issues <a href="lwg-closed.html#140">140</a> to
+<a href="lwg-defects.html#189">189</a>. Issues list split into separate "active" and
+"closed" documents. (99-0030/N1206, 25 Aug 99)
+</li>
+<li>R8:
+post-Dublin mailing. Updated to reflect LWG and full committee actions
+in Dublin. (99-0016/N1193, 21 Apr 99)
+</li>
+<li>R7:
+pre-Dublin updated: Added issues <a href="lwg-closed.html#130">130</a>, <a href="lwg-closed.html#131">131</a>,
+<a href="lwg-defects.html#132">132</a>, <a href="lwg-defects.html#133">133</a>, <a href="lwg-defects.html#134">134</a>,
+<a href="lwg-closed.html#135">135</a>, <a href="lwg-defects.html#136">136</a>, <a href="lwg-defects.html#137">137</a>,
+<a href="lwg-closed.html#138">138</a>, <a href="lwg-defects.html#139">139</a> (31 Mar 99)
+</li>
+<li>R6:
+pre-Dublin mailing. Added issues <a href="lwg-defects.html#127">127</a>, <a href="lwg-closed.html#128">128</a>,
+and <a href="lwg-defects.html#129">129</a>. (99-0007/N1194, 22 Feb 99)
+</li>
+<li>R5:
+update issues <a href="lwg-defects.html#103">103</a>, <a href="lwg-defects.html#112">112</a>; added issues
+<a href="lwg-defects.html#114">114</a> to <a href="lwg-defects.html#126">126</a>. Format revisions to prepare
+for making list public. (30 Dec 98)
+</li>
+<li>R4:
+post-Santa Cruz II updated: Issues <a href="lwg-defects.html#110">110</a>,
+<a href="lwg-closed.html#111">111</a>, <a href="lwg-defects.html#112">112</a>, <a href="lwg-closed.html#113">113</a> added, several
+issues corrected. (22 Oct 98)
+</li>
+<li>R3:
+post-Santa Cruz II: Issues <a href="lwg-closed.html#94">94</a> to <a href="lwg-active.html#109">109</a>
+added, many issues updated to reflect LWG consensus (12 Oct 98)
+</li>
+<li>R2:
+pre-Santa Cruz II: Issues <a href="lwg-closed.html#73">73</a> to <a href="lwg-closed.html#93">93</a> added,
+issue <a href="lwg-defects.html#17">17</a> updated. (29 Sep 98)
+</li>
+<li>R1:
+Correction to issue <a href="lwg-defects.html#55">55</a> resolution, <a href="lwg-defects.html#60">60</a> code
+format, <a href="lwg-defects.html#64">64</a> title. (17 Sep 98)
+</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 LWG. Any <b>Proposed Resolution</b> is purely a
+ suggestion from the issue submitter, and should not be construed as
+ the view of LWG.</p>
+
+ <p>
+<b><a name="Open">Open</a></b> - The LWG 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 LWG awaits
+ exact <b>Proposed Resolution</b> wording for review.</li>
+ <li>The LWG wishes to consult additional technical experts before
+ proceeding.</li>
+ <li>The issue may require further study.</li>
+ </ul>
+
+ <p>A <b>Proposed Resolution</b> for an open issue is still not be
+ construed as the view of LWG. 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 LWG has reached consensus that
+ the issue is a duplicate of another issue, and will not be further
+ dealt with. A <b>Rationale</b> identities the duplicated issue's
+ issue number. </p>
+
+ <p>
+<b><a name="NAD">NAD</a></b> - The LWG has reached consensus that
+ the issue is not a defect in the Standard, and the issue is ready to
+ forward to the full committee as a proposed record of response. A
+ <b>Rationale</b> discusses the LWG's reasoning.</p>
+
+ <p>
+<b><a name="Review">Review</a></b> - Exact wording of a
+ <b>Proposed Resolution</b> is now available for review on an issue
+ for which the LWG previously reached informal consensus.</p>
+
+ <p>
+<b><a name="Ready">Ready</a></b> - The LWG has reached consensus
+ that the issue is a defect in the Standard, the <b>Proposed
+ Resolution</b> is correct, and the issue is ready to forward to the
+ full committee for further action as a Defect Report (DR).</p>
+
+ <p>
+<b><a name="DR">DR</a></b> - (Defect Report) - The full J16
+ committee has voted to forward the issue to the Project Editor to be
+ processed as a Potential Defect Report. The Project Editor reviews
+ the issue, and then forwards it to the WG21 Convenor, who returns it
+ to the full committee for final disposition. This issues list
+ accords the status of DR to all these Defect Reports regardless of
+ where they are in that process.</p>
+
+ <p>
+<b><a name="TC">TC</a></b> - (Technical Corrigenda) - The full
+ WG21 committee has voted to accept the Defect Report's Proposed
+ Resolution as a Technical Corrigenda. Action on this issue is thus
+ complete and no further action is possible under ISO rules.</p>
+
+ <p>
+<b><a name="RR">RR</a></b> - (Record of Response) - The full WG21
+ committee has determined that this issue is not a defect in the
+ Standard. Action on this issue is thus complete and no further
+ action is possible under ISO rules.</p>
+
+ <p>
+<b><a name="Future">Future</a></b> - In addition to the regular
+ status, the LWG believes that this issue should be revisited at the
+ next revision of the standard. It is usually paired with NAD.</p>
+
+ <p>Issues are always given the status of <a href="lwg-active.html#New">New</a> when
+ they first appear on the issues list. They may progress to
+ <a href="lwg-active.html#Open">Open</a> or <a href="lwg-active.html#Review">Review</a> while the LWG
+ is actively working on them. When the LWG has reached consensus on
+ the disposition of an issue, the status will then change to
+ <a href="lwg-active.html#Dup">Dup</a>, <a href="lwg-active.html#NAD">NAD</a>, or <a href="lwg-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="lwg-active.html#DR">DR</a>). These in turn may
+ become the basis for Technical Corrigenda (<a href="lwg-active.html#TC">TC</a>),
+ or are closed without action other than a Record of Response
+ (<a href="lwg-active.html#RR">RR</a> ). The intent of this LWG process is that
+ only issues which are truly defects in the Standard move to the
+ formal ISO DR status.
+ </p>
+
+<h2>Active Issues</h2>
+<hr>
+<a name="23"><h3>23. Num_get overflow result</h3></a><p>
+<b>Section:</b> 22.2.2.1.2 <a href="lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The current description of numeric input does not account for the possibility of
+overflow. This is an implicit result of changing the description to rely on the definition
+of scanf() (which fails to report overflow), and conflicts with the documented behavior of
+traditional and current implementations. </p>
+
+<p>Users expect, when reading a character sequence that results in a value unrepresentable
+in the specified type, to have an error reported. The standard as written does not permit
+this. </p>
+
+<p><b>Further comments from Dietmar:</b></p>
+
+<p>
+I don't feel comfortable with the proposed resolution to issue 23: It
+kind of simplifies the issue to much. Here is what is going on:
+</p>
+
+<p>
+Currently, the behavior of numeric overflow is rather counter intuitive
+and hard to trace, so I will describe it briefly:
+</p>
+
+<ul>
+ <li>
+ According to 22.2.2.1.2
+ paragraph 11 <tt>failbit</tt> is set if <tt>scanf()</tt> would
+ return an input error; otherwise a value is converted to the rules
+ of <tt>scanf</tt>.
+ </li>
+ <li>
+ <tt>scanf()</tt> is defined in terms of <tt>fscanf()</tt>.
+ </li>
+ <li>
+ <tt>fscanf()</tt> returns an input failure if during conversion no
+ character matching the conversion specification could be extracted
+ before reaching EOF. This is the only reason for <tt>fscanf()</tt>
+ to fail due to an input error and clearly does not apply to the case
+ of overflow.
+ </li>
+ <li>
+ Thus, the conversion is performed according to the rules of
+ <tt>fscanf()</tt> which basically says that <tt>strtod</tt>,
+ <tt>strtol()</tt>, etc. are to be used for the conversion.
+ </li>
+ <li>
+ The <tt>strtod()</tt>, <tt>strtol()</tt>, etc. functions consume as
+ many matching characters as there are and on overflow continue to
+ consume matching characters but also return a value identical to
+ the maximum (or minimum for signed types if there was a leading minus)
+ value of the corresponding type and set <tt>errno</tt> to <tt>ERANGE</tt>.
+ </li>
+ <li>
+ Thus, according to the current wording in the standard, overflows
+ can be detected! All what is to be done is to check <tt>errno</tt>
+ after reading an element and, of course, clearing <tt>errno</tt>
+ before trying a conversion. With the current wording, it can be
+ detected whether the overflow was due to a positive or negative
+ number for signed types.
+ </li>
+</ul>
+
+<p>
+Now the proposed resolution results in not modifying the value passed
+as last argument if an overflow is encountered but <tt>failbit</tt>
+is set. Checking <tt>errno</tt> for <tt>ERANGE</tt> still allows for
+detection of an overflow but not what the sign was.
+</p>
+
+<p>
+Actually, my problem is not that much with the sign but this is at least
+making things worse... My problem is more that it is still necessary
+to check <tt>errno</tt> for the error description. Thus, I propose the
+following resolution:
+</p>
+
+<p>Change paragraph 11 from</p>
+
+<blockquote>
+<p>
+<b>-11-</b> <b>Stage 3:</b>
+The result of stage 2 processing can be one of</p>
+
+<ul>
+<li>A sequence of <tt>char</tt>s
+has been accumulated in stage 2 that is converted (according to the
+rules of <tt>scanf)</tt> to a value of the type of <tt><i>val</i></tt>.
+This value is stored in <tt><i>val</i></tt> and
+<tt>ios_base::goodbit</tt> is stored in <tt><i>err</i></tt>.</li>
+
+<li>The sequence of <tt>char</tt>s
+accumulated in stage 2 would have caused scanf to report an input failure.
+<tt>ios_base::failbit</tt> is assigned to <i>err</i>.</li>
+</ul>
+</blockquote>
+
+<p>to become</p>
+
+<blockquote>
+<p>
+<b>-11-</b> <b>Stage 3:</b>
+The result of stage 2 processing can be one of</p>
+
+<ul>
+<li>A sequence of <tt>char</tt>s
+has been accumulated in stage 2 that is converted (according to the
+rules of <tt>scanf)</tt> to a value of the type of <tt><i>val</i></tt>.
+This value is stored in <tt><i>val</i></tt>. If the conversion reported
+an overflow error for the type of <tt><i>val</i></tt> (ie.
+<tt><i>errno</i></tt> would be set to <tt>ERANGE</tt> by the used
+conversion function) then <tt>ios_base::failbit</tt> is stored in
+<tt><i>err</i></tt>, otherwise <tt>ios_base::goodbit</tt> is stored in
+<tt><i>err</i></tt>.</li>
+
+<li>The sequence of <tt>char</tt>s accumulated in stage 2 would have
+caused scanf to report an input failure. <tt>ios_base::failbit</tt>
+is assigned to <i>err</i>.</li>
+</ul>
+</blockquote>
+
+<p>
+With this definition, overflow can be detected easily by storing a value
+different from the maximum value in <tt><i>val</i></tt> and checking whether
+this value was modified in case <tt>failbit</tt> is set: If it was, there
+was an overflow error, otherwise some other input error occurred (under the
+conditions for the second bullet <tt><i>val</i></tt> is not changed).
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.2.1.2 , paragraph 11, second bullet item,
+change </p>
+
+<blockquote>
+ <p>The sequence of chars accumulated in stage 2 would have caused scanf to report an input
+ failure. </p>
+</blockquote>
+
+<p>to </p>
+
+<blockquote>
+ <p>The sequence of chars accumulated in stage 2 would have caused scanf to report an input
+ failure, or the value of the sequence cannot be represented in the type of _val_. </p>
+</blockquote>
+
+<p><i>[post-Toronto: "cannot be represented" is probably wrong:
+infinity can be represented on an IEC559 platform, but 0.1 cannot be
+represented exactly. However, the alternate proposal may be wrong as
+well. It's not clear whether overflow (and underflow?) should always
+be treated as errors. This issue requires much more thought]</i></p>
+
+<hr>
+<a name="44"><h3>44. Iostreams use operator== on int_type values</h3></a><p>
+<b>Section:</b> 27 <a href="lib-iostreams.html#lib.input.output"> [lib.input.output]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>Many of the specifications for iostreams specify that character
+values or their int_type equivalents are compared using operators ==
+or !=, though in other places traits::eq() or traits::eq_int_type is
+specified to be used throughout. This is an inconsistency; we should
+change uses of == and != to use the traits members instead. </p>
+<p><b>Proposed resolution:</b></p>
+
+<p><i>[Kona: Nathan to supply proposed wording]</i></p>
+
+<p><i>[
+Tokyo: the LWG reaffirmed that this is a defect, and requires careful
+review of clause 27 as the changes are context sensitive.
+]</i></p>
+
+<hr>
+<a name="49"><h3>49. Underspecification of ios_base::sync_with_stdio</h3></a><p>
+<b>Section:</b> 27.4.2.4 <a href="lib-iostreams.html#lib.ios.members.static"> [lib.ios.members.static]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 21 Jun 1998</p>
+<p>Two problems</p>
+
+<p>(1) 27.4.2.4 doesn't say what ios_base::sync_with_stdio(f)
+returns. Does it return f, or does it return the previous
+synchronization state? My guess is the latter, but the standard
+doesn't say so.</p>
+
+<p>(2) 27.4.2.4 doesn't say what it means for streams to be
+synchronized with stdio. Again, of course, I can make some
+guesses. (And I'm unhappy about the performance implications of those
+guesses, but that's another matter.)</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the following sentence in 27.4.2.4
+returns clause from:</p>
+
+<blockquote>
+ <p>
+<tt>true</tt> if the standard iostream objects (27.3) are
+ synchronized and otherwise returns <tt>false</tt>.</p>
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ <p>
+<tt>true</tt> if the previous state of the standard iostream
+ objects (27.3) was synchronized and otherwise returns
+ <tt>false</tt>.</p>
+</blockquote>
+
+<p>Add the following immediately after 27.4.2.4 ,
+paragraph 2:</p>
+
+<blockquote>
+<p>When a standard iostream object str is <i>synchronized</i> with a
+standard stdio stream f, the effect of inserting a character c by</p>
+<pre>
+ fputc(f, c);
+</pre>
+
+<p>is the same as the effect of</p>
+<pre>
+ str.rdbuf()->sputc(c);
+</pre>
+
+<p>for any sequence of characters; the effect of extracting a
+character c by</p>
+<pre>
+ c = fgetc(f);
+</pre>
+
+<p>is the same as the effect of:</p>
+<pre>
+ c = str.rdbuf()->sbumpc(c);
+</pre>
+
+<p>for any sequences of characters; and the effect of pushing
+back a character c by</p>
+<pre>
+ ungetc(c, f);
+</pre>
+
+<p>is the same as the effect of</p>
+<pre>
+ str.rdbuf()->sputbackc(c);
+</pre>
+
+<p>for any sequence of characters. [<i>Footnote</i>: This implies
+that operations on a standard iostream object can be mixed arbitrarily
+with operations on the corresponding stdio stream. In practical
+terms, synchronization usually means that a standard iostream object
+and a standard stdio object share a buffer. <i>--End Footnote</i>]</p>
+</blockquote>
+
+<p><i>[pre-Copenhagen: PJP and Matt contributed the definition
+of "synchronization"]</i></p>
+
+<p><i>[post-Copenhagen: proposed resolution was revised slightly:
+text was added in the non-normative footnote to say that operations
+on the two streams can be mixed arbitrarily.]</i></p>
+<hr>
+<a name="76"><h3>76. Can a <tt>codecvt</tt> facet always convert one internal character at a time?</h3></a><p>
+<b>Section:</b> 22.2.1.5 <a href="lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 25 Sep 1998</p>
+<p>This issue concerns the requirements on classes derived from
+<tt>codecvt</tt>, including user-defined classes. What are the
+restrictions on the conversion from external characters
+(e.g. <tt>char</tt>) to internal characters (e.g. <tt>wchar_t</tt>)?
+Or, alternatively, what assumptions about <tt>codecvt</tt> facets can
+the I/O library make? </p>
+
+<p>The question is whether it's possible to convert from internal
+characters to external characters one internal character at a time,
+and whether, given a valid sequence of external characters, it's
+possible to pick off internal characters one at a time. Or, to put it
+differently: given a sequence of external characters and the
+corresponding sequence of internal characters, does a position in the
+internal sequence correspond to some position in the external
+sequence? </p>
+
+<p>To make this concrete, suppose that <tt>[first, last)</tt> is a
+sequence of <i>M</i> external characters and that <tt>[ifirst,
+ilast)</tt> is the corresponding sequence of <i>N</i> internal
+characters, where <i>N > 1</i>. That is, <tt>my_encoding.in()</tt>,
+applied to <tt>[first, last)</tt>, yields <tt>[ifirst,
+ilast)</tt>. Now the question: does there necessarily exist a
+subsequence of external characters, <tt>[first, last_1)</tt>, such
+that the corresponding sequence of internal characters is the single
+character <tt>*ifirst</tt>?
+</p>
+
+<p>(What a "no" answer would mean is that
+<tt>my_encoding</tt> translates sequences only as blocks. There's a
+sequence of <i>M</i> external characters that maps to a sequence of
+<i>N</i> internal characters, but that external sequence has no
+subsequence that maps to <i>N-1</i> internal characters.) </p>
+
+<p>Some of the wording in the standard, such as the description of
+<tt>codecvt::do_max_length</tt> (22.2.1.5.2 ,
+paragraph 11) and <tt>basic_filebuf::underflow</tt> (27.8.1.4 , paragraph 3) suggests that it must always be
+possible to pick off internal characters one at a time from a sequence
+of external characters. However, this is never explicitly stated one
+way or the other. </p>
+
+<p>This issue seems (and is) quite technical, but it is important if
+we expect users to provide their own encoding facets. This is an area
+where the standard library calls user-supplied code, so a well-defined
+set of requirements for the user-supplied code is crucial. Users must
+be aware of the assumptions that the library makes. This issue affects
+positioning operations on <tt>basic_filebuf</tt>, unbuffered input,
+and several of <tt>codecvt</tt>'s member functions. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following text as a new paragraph, following 22.2.1.5.2 paragraph 2:</p>
+
+<blockquote>
+<p>A <tt>codecvt</tt> facet that is used by <tt>basic_filebuf</tt>
+(27.8 ) must have the property that if</p>
+<pre>
+ do_out(state, from, from_end, from_next, to, to_lim, to_next)
+</pre>
+would succeed (return value would be <tt>ok</tt>), where
+<tt>from != from_end</tt>, then
+<pre>
+ do_out(state, from, from + 1, from_next, to, to_end, to_next)
+</pre>
+must also succeed, and that if
+<pre>
+ do_in(state, from, from_end, from_next, to, to_lim, to_next)
+</pre>
+would succeed, where <tt>to != to_lim</tt>, then
+<pre>
+ do_in(state, from, from_end, from_next, to, to + 1, to_next)
+</pre>
+<p>must also succeed. [<i>Footnote:</i> Informally, this means that
+<tt>basic_filebuf</tt> assumes that the mapping from internal to
+external characters is 1 to N: a <tt>codecvt</tt> that is used by
+<tt>basic_filebuf</tt> must be able to translate characters one
+internal character at a time. <i>--End Footnote</i>]</p>
+</blockquote>
+
+<p><b>Rationale:</b></p>
+
+ <p>The proposed resoluion says that conversions can be performed one
+ internal character at a time. This rules out some encodings that
+ would otherwise be legal. The alternative answer would mean there
+ would be some internal positions that do not correspond to any
+ external file position.</p>
+ <p>
+ An example of an encoding that this rules out is one where the
+ <tt>internT</tt> and <tt>externT</tt> are of the same type, and
+ where the internal sequence <tt>c1 c2</tt> corresponds to the
+ external sequence <tt>c2 c1</tt>.
+ </p>
+ <p>It was generally agreed that <tt>basic_filebuf</tt> relies
+ on this property: it was designed under the assumption that
+ the external-to-internal mapping is N-to-1, and it is not clear
+ that <tt>basic_filebuf</tt> is implementable without that
+ restriction.
+ </p>
+ <p>
+ The proposed resolution is expressed as a restriction on
+ <tt>codecvt</tt> when used by <tt>basic_filebuf</tt>, rather
+ than a blanket restriction on all <tt>codecvt</tt> facets,
+ because <tt>basic_filebuf</tt> is the only other part of the
+ library that uses <tt>codecvt</tt>. If a user wants to define
+ a <tt>codecvt</tt> facet that implements a more general N-to-M
+ mapping, there is no reason to prohibit it, so long as the user
+ does not expect <tt>basic_filebuf</tt> to be able to use it.
+ </p>
+<hr>
+<a name="91"><h3>91. Description of operator>> and getline() for string<> might cause endless loop</h3></a><p>
+<b>Section:</b> 21.3.7.9 <a href="lib-strings.html#lib.string.io"> [lib.string.io]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>Operator >> and getline() for strings read until eof()
+in the input stream is true. However, this might never happen, if the
+stream can't read anymore without reaching EOF. So shouldn't it be
+changed into that it reads until !good() ? </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 21.3.7.9 , paragraph 1, replace:</p>
+<blockquote>
+Effects: Begins by constructing a sentry object k as if k were
+constructed by typename basic_istream<charT,traits>::sentry k( is). If
+bool( k) is true, it calls str.erase() and then extracts characters
+from is and appends them to str as if by calling str.append(1, c). If
+is.width() is greater than zero, the maximum number n of characters
+appended is is.width(); otherwise n is str.max_size(). Characters are
+extracted and appended until any of the following occurs:
+</blockquote>
+<p>with:</p>
+<blockquote>
+Effects: Behaves as an unformatted input function (27.6.1.2 ). After constructing a sentry object, if the
+sentry converts to true, calls str.erase() and then extracts
+characters from is and appends them to str as if by calling
+str.append(1,c). If is.width() is greater than zero, the maximum
+number n of characters appended is is.width(); otherwise n is
+str.max_size(). Characters are extracted and appended until any of the
+following occurs:
+</blockquote>
+
+<p>In 21.3.7.9 , paragraph 6, replace</p>
+<blockquote>
+Effects: Begins by constructing a sentry object k as if by typename
+basic_istream<charT,traits>::sentry k( is, true). If bool( k) is true,
+it calls str.erase() and then extracts characters from is and appends
+them to str as if by calling str.append(1, c) until any of the
+following occurs:
+</blockquote>
+<p>with:</p>
+<blockquote>
+Effects: Behaves as an unformatted input function (27.6.1.2 ). After constructing a sentry object, if the
+sentry converts to true, calls str.erase() and then extracts
+characters from is and appends them to str as if by calling
+str.append(1,c) until any of the following occurs:
+</blockquote>
+
+<p><b>Rationale:</b></p>
+<p>The real issue here is whether or not these string input functions
+perform formatted input. If they do, then they get their characters
+from a streambuf, rather than by calling an istream's member functions,
+and a streambuf signals failure either by returning eof or by throwing
+an exception. The proposed resolution makes it clear that these two
+functions do perform formatted input.</p>
+<hr>
+<a name="92"><h3>92. Incomplete Algorithm Requirements</h3></a><p>
+<b>Section:</b> 25 <a href="lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>The standard does not state, how often a function object is copied,
+called, or the order of calls inside an algorithm. This may lead to
+surprising/buggy behavior. Consider the following example: </p>
+
+<pre>class Nth { // function object that returns true for the nth element
+ private:
+ int nth; // element to return true for
+ int count; // element counter
+ public:
+ Nth (int n) : nth(n), count(0) {
+ }
+ bool operator() (int) {
+ return ++count == nth;
+ }
+};
+....
+// remove third element
+ list<int>::iterator pos;
+ pos = remove_if(coll.begin(),coll.end(), // range
+ Nth(3)), // remove criterion
+ coll.erase(pos,coll.end()); </pre>
+
+<p>This call, in fact removes the 3rd <b>AND the 6th</b> element. This
+happens because the usual implementation of the algorithm copies the
+function object internally: </p>
+
+<pre>template <class ForwIter, class Predicate>
+ForwIter std::remove_if(ForwIter beg, ForwIter end, Predicate op)
+{
+ beg = find_if(beg, end, op);
+ if (beg == end) {
+ return beg;
+ }
+ else {
+ ForwIter next = beg;
+ return remove_copy_if(++next, end, beg, op);
+ }
+} </pre>
+
+<p>The algorithm uses find_if() to find the first element that should
+be removed. However, it then uses a copy of the passed function object
+to process the resulting elements (if any). Here, Nth is used again
+and removes also the sixth element. This behavior compromises the
+advantage of function objects being able to have a state. Without any
+cost it could be avoided (just implement it directly instead of
+calling find_if()). </p>
+<p><b>Proposed resolution:</b></p>
+<p> In [lib.function.objects] 20.3 Function objects add as new
+paragraph 6 (or insert after paragraph 1): </p>
+
+<p>Option 1: </p>
+<blockquote>
+Predicates are functions or function objects that fulfill the
+following requirements:<br> - They return a Boolean value (bool
+or a value convertible to bool)<br> - It doesn't matter for the
+behavior of a predicate how often it is copied or assigned and how
+often it is called.
+</blockquote>
+
+<p>Option 2: </p>
+<blockquote>
+- if it's a function:<br> - All calls with the same
+argument values yield the same result.<br> - if it's a function
+object:<br> - In any sequence of calls to operator () without
+calling any non-constant member function, all calls with the same
+argument values yield the same result. <br> - After an assignment
+or copy both objects return the same result for the same values.
+</blockquote>
+
+<p><i>[Santa Cruz: The LWG believes that there may be more to this than
+meets the eye. It applies to all function objects, particularly
+predicates. Two questions: (1) must a function object be
+copyable? (2) how many times is a function object called? These
+are in effect questions about state. Function objects appear to
+require special copy semantics to make state work, and may fail if
+calling alters state and calling occurs an unexpected number of
+times.]</i></p>
+
+<p><i>[Dublin: Pete Becker felt that this may not be a defect,
+but rather something that programmers need to be educated about.
+There was discussion of adding wording to the effect that the number
+and order of calls to function objects, including predicates, not
+affect the behavior of the function object.]</i></p>
+
+<p><i>[Pre-Kona: Nico comments: It seems the problem is that we don't
+have a clear statement of "predicate" in the
+standard. People including me seemed to think "a function
+returning a Boolean value and being able to be called by an STL
+algorithm or be used as sorting criterion or ... is a
+predicate". But a predicate has more requirements: It should
+never change its behavior due to a call or being copied. IMHO we have
+to state this in the standard. If you like, see section 8.1.4 of my
+library book for a detailed discussion.]</i></p>
+
+<p><i>[Kona: Nico will provide wording to the effect that "unless
+otherwise specified, the number of copies of and calls to function
+objects by algorithms is unspecified". Consider placing in
+25 after paragraph 9.]</i></p>
+
+<p><i>[Pre-Tokyo: Angelika Langer comments: if the resolution is
+that algorithms are free to copy and pass around any function objects,
+then it is a valid question whether they are also allowed to change
+the type information from reference type to value type.]</i></p>
+
+<p><i>[Tokyo: Nico will discuss this further with Matt as there are
+multiple problems beyond the underlying problem of no definition of
+"Predicate".]</i></p>
+
+<p><i>[Post-Tokyo: Nico provided the above proposed
+resolutions.]</i></p>
+
+<hr>
+<a name="96"><h3>96. Vector<bool> is not a container</h3></a><p>
+<b>Section:</b> 23.2.5 <a href="lib-containers.html#lib.vector.bool"> [lib.vector.bool]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> AFNOR <b>Date:</b> 7 Oct 1998</p>
+<p>
+<tt>vector<bool></tt> is not a container as its reference and
+pointer types are not references and pointers. </p>
+
+<p>Also it forces everyone to have a space optimization instead of a
+speed one.</p>
+
+<p>
+<b>See also:</b> 99-0008 == N1185 Vector<bool> is
+Nonconforming, Forces Optimization Choice.</p>
+<p><b>Proposed resolution:</b></p>
+
+<p><i>[In Santa Cruz the LWG felt that this was Not A Defect.]</i></p>
+
+<p><i>[In Dublin many present felt that failure to meet Container
+requirements was a defect. There was disagreement as to whether
+or not the optimization requirements constituted a defect.]</i></p>
+
+<p><i>[The LWG looked at the following resolutions in some detail:
+<br>
+ * Not A Defect.<br>
+ * Add a note explaining that vector<bool> does not meet
+Container requirements.<br>
+ * Remove vector<bool>.<br>
+ * Add a new category of container requirements which
+vector<bool> would meet.<br>
+ * Rename vector<bool>.<br>
+<br>
+No alternative had strong, wide-spread, support and every alternative
+had at least one "over my dead body" response.<br>
+<br>
+There was also mention of a transition scheme something like (1) add
+vector_bool and deprecate vector<bool> in the next standard. (2)
+Remove vector<bool> in the following standard.]</i></p>
+
+<p><i>[Modifying container requirements to permit returning proxies
+(thus allowing container requirements conforming vector<bool>)
+was also discussed.]</i></p>
+
+<p><i>[It was also noted that there is a partial but ugly workaround in
+that vector<bool> may be further specialized with a customer
+allocator.]</i></p>
+
+<p><i>[Kona: Herb Sutter presented his paper J16/99-0035==WG21/N1211,
+vector<bool>: More Problems, Better Solutions. Much discussion
+of a two step approach: a) deprecate, b) provide replacement under a
+new name. LWG straw vote on that: 1-favor, 11-could live with, 2-over
+my dead body. This resolution was mentioned in the LWG report to the
+full committee, where several additional committee members indicated
+over-my-dead-body positions.]</i></p>
+
+<p><i>[Tokyo: Not discussed by the full LWG; no one claimed new
+insights and so time was more productively spent on other issues. In
+private discussions it was asserted that requirements for any solution
+include 1) Increasing the full committee's understanding of the
+problem, and 2) providing compiler vendors, authors, teachers, and of
+course users with specific suggestions as to how to apply the eventual
+solution.]</i></p>
+
+<hr>
+<a name="98"><h3>98. Input iterator requirements are badly written</h3></a><p>
+<b>Section:</b> 24.1.1 <a href="lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> AFNOR <b>Date:</b> 7 Oct 1998</p>
+<p>Table 72 in 24.1.1 specifies semantics for
+<tt>*r++</tt> of:</p>
+
+<p> <tt>{ T tmp = *r; ++r; return tmp; }</tt>
+</p>
+
+<p>This does not work for pointers and over constrains implementors.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add for *r++: “To call the copy constructor for the type T is
+allowed but not required.”</p>
+
+<p><i>[Dublin: Pete Becker will attempt improved wording.]</i></p>
+
+<p><i>[Tokyo: The essence of the issue seems to have escaped.
+Pete will email Valentin to try to recapture it.]</i></p>
+<hr>
+<a name="109"><h3>109. Missing binders for non-const sequence elements</h3></a><p>
+<b>Section:</b> 20.3.6 <a href="lib-utilities.html#lib.binders"> [lib.binders]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Bjarne Stroustrup <b>Date:</b> 7 Oct 1998</p>
+<p>There are no versions of binders that apply to non-const elements
+of a sequence. This makes examples like for_each() using bind2nd() on
+page 521 of "The C++ Programming Language (3rd)"
+non-conforming. Suitable versions of the binders need to be added.</p>
+
+<p>Further discussion from Nico:</p>
+
+<p>What is probably meant here is shown in the following example:</p>
+
+<pre>class Elem {
+ public:
+ void print (int i) const { }
+ void modify (int i) { }
+}; </pre>
+<pre>int main()
+{
+ vector<Elem> coll(2);
+ for_each (coll.begin(), coll.end(), bind2nd(mem_fun_ref(&Elem::print),42)); // OK
+ for_each (coll.begin(), coll.end(), bind2nd(mem_fun_ref(&Elem::modify),42)); // ERROR
+}</pre>
+
+<p>The error results from the fact that bind2nd() passes its first
+argument (the argument of the sequence) as constant reference. See the
+following typical implementation:</p>
+
+<blockquote>
+ <pre>template <class Operation>
+class binder2nd
+ : public unary_function<typename Operation::first_argument_type,
+ typename Operation::result_type> {
+protected:
+ Operation op;
+ typename Operation::second_argument_type value;
+public:
+ binder2nd(const Operation& o,
+ const typename Operation::second_argument_type& v)
+ : op(o), value(v) {} </pre>
+ <pre> typename Operation::result_type
+ operator()(const typename Operation::first_argument_type& x) const {
+ return op(x, value);
+ }
+};</pre>
+</blockquote>
+
+<p>The solution is to overload operator () of bind2nd for non-constant arguments:</p>
+
+<blockquote>
+ <pre>template <class Operation>
+class binder2nd
+ : public unary_function<typename Operation::first_argument_type,
+ typename Operation::result_type> {
+protected:
+ Operation op;
+ typename Operation::second_argument_type value;
+public:
+ binder2nd(const Operation& o,
+ const typename Operation::second_argument_type& v)
+ : op(o), value(v) {} </pre>
+ <pre> typename Operation::result_type
+ operator()(const typename Operation::first_argument_type& x) const {
+ return op(x, value);
+ }
+ typename Operation::result_type
+ operator()(typename Operation::first_argument_type& x) const {
+ return op(x, value);
+ }
+};</pre>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>In 20.3.6.1 in the declaration of binder1st after:</p>
+<blockquote>
+ <p><tt>typename Operation::result_type<br>
+ operator()(const typename Operation::second_argument_type& x) const;</tt></p>
+</blockquote>
+<p>insert:</p>
+<blockquote>
+ <p><tt>typename Operation::result_type<br>
+ operator()(typename Operation::second_argument_type& x) const;</tt></p>
+</blockquote>
+<p>In 20.3.6.3 in the declaration of binder2nd after:</p>
+<blockquote>
+ <p><tt>typename Operation::result_type<br>
+ operator()(const typename Operation::first_argument_type& x) const;</tt></p>
+</blockquote>
+<p>insert:</p>
+<blockquote>
+ <p><tt>typename Operation::result_type<br>
+ operator()(typename Operation::first_argument_type& x) const;</tt></p>
+</blockquote>
+
+<p><i>[Kona: The LWG discussed this at some length.It was agreed that
+this is a mistake in the design, but there was no consensus on whether
+it was a defect in the Standard. Straw vote: NAD - 5. Accept
+proposed resolution - 3. Leave open - 6.]</i></p>
+
+<p><i>[Copenhagen: It was generally agreed that this was a defect.
+Strap poll: NAD - 0. Accept proposed resolution - 10.
+Leave open - 1.]</i></p>
+
+<hr>
+<a name="117"><h3>117. <tt>basic_ostream</tt> uses nonexistent <tt>num_put</tt> member functions</h3></a><p>
+<b>Section:</b> 27.6.2.5.2 <a href="lib-iostreams.html#lib.ostream.inserters.arithmetic"> [lib.ostream.inserters.arithmetic]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 20 Nov 1998</p>
+<p>The <b>effects</b> clause for numeric inserters says that
+insertion of a value <tt>x</tt>, whose type is either <tt>bool</tt>,
+<tt>short</tt>, <tt>unsigned short</tt>, <tt>int</tt>, <tt>unsigned
+int</tt>, <tt>long</tt>, <tt>unsigned long</tt>, <tt>float</tt>,
+<tt>double</tt>, <tt>long double</tt>, or <tt>const void*</tt>, is
+delegated to <tt>num_put</tt>, and that insertion is performed as if
+through the following code fragment: </p>
+
+<pre>bool failed = use_facet<
+ num_put<charT,ostreambuf_iterator<charT,traits> >
+ >(getloc()).put(*this, *this, fill(), val). failed();</pre>
+
+<p>This doesn't work, because <tt>num_put<></tt>::put is only
+overloaded for the types <tt>bool</tt>, <tt>long</tt>, <tt>unsigned
+long</tt>, <tt>double</tt>, <tt>long double</tt>, and <tt>const
+void*</tt>. That is, the code fragment in the standard is incorrect
+(it is diagnosed as ambiguous at compile time) for the types
+<tt>short</tt>, <tt>unsigned short</tt>, <tt>int</tt>, <tt>unsigned
+int</tt>, and <tt>float</tt>. </p>
+
+<p>We must either add new member functions to <tt>num_put</tt>, or
+else change the description in <tt>ostream</tt> so that it only calls
+functions that are actually there. I prefer the latter. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace 27.6.2.5.2, paragraph 1 with the following: </p>
+
+<blockquote>
+<p>
+The classes num_get<> and num_put<> handle locale­dependent numeric
+formatting and parsing. These inserter functions use the imbued
+locale value to perform numeric formatting. When val is of type bool,
+long, unsigned long, double, long double, or const void*, the
+formatting conversion occurs as if it performed the following code
+fragment:
+</p>
+
+<pre>
+bool failed = use_facet<
+ num_put<charT,ostreambuf_iterator<charT,traits> >
+ >(getloc()).put(*this, *this, fill(), val). failed();
+</pre>
+
+<p>
+When val is of type short the formatting conversion occurs as if it
+performed the following code fragment:
+</p>
+
+<pre>
+ios_base::fmtflags baseflags = ios_base::flags() & ios_base::basefield;
+bool failed = use_facet<
+ num_put<charT,ostreambuf_iterator<charT,traits> >
+ >(getloc()).put(*this, *this, fill(),
+ baseflags == ios_base::oct || baseflags == ios_base::hex
+ ? static_cast<long>(static_cast<unsigned short>(val))
+ : static_cast<long>(val)). failed();
+</pre>
+
+<p>
+When val is of type int the formatting conversion occurs as if it performed
+the following code fragment:
+</p>
+
+<pre>
+ios_base::fmtflags baseflags = ios_base::flags() & ios_base::basefield;
+bool failed = use_facet<
+ num_put<charT,ostreambuf_iterator<charT,traits> >
+ >(getloc()).put(*this, *this, fill(),
+ baseflags == ios_base::oct || baseflags == ios_base::hex
+ ? static_cast<long>(static_cast<unsigned int>(val))
+ : static_cast<long>(val)). failed();
+</pre>
+
+<p>
+When val is of type unsigned short or unsigned int the formatting conversion
+occurs as if it performed the following code fragment:
+</p>
+
+<pre>
+bool failed = use_facet<
+ num_put<charT,ostreambuf_iterator<charT,traits> >
+ >(getloc()).put(*this, *this, fill(), static_cast<unsigned long>(val)).
+failed();
+</pre>
+
+<p>
+When val is of type float the formatting conversion occurs as if it
+performed the following code fragment:
+</p>
+
+<pre>
+bool failed = use_facet<
+ num_put<charT,ostreambuf_iterator<charT,traits> >
+ >(getloc()).put(*this, *this, fill(), static_cast<double>(val)).
+failed();
+</pre>
+
+</blockquote>
+
+<p><i>[post-Toronto: This differs from the previous proposed
+resolution; PJP provided the new wording. The differences are in
+signed short and int output.]</i></p>
+<p><b>Rationale:</b></p>
+<p>The original proposed resolution was to cast int and short to long,
+unsigned int and unsigned short to unsigned long, and float to double,
+thus ensuring that we don't try to use nonexistent num_put<>
+member functions. The current proposed resolution is more
+complicated, but gives more expected results for hex and octal output
+of signed short and signed int. (On a system with 16-bit short, for
+example, printing short(-1) in hex format should yield 0xffff.)</p>
+<hr>
+<a name="120"><h3>120. Can an implementor add specializations?</h3></a><p>
+<b>Section:</b> 17.4.3.1 <a href="lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998</p>
+<p>Section 17.4.3.1 says: </p>
+
+<blockquote>
+ <p>It is undefined for a C++ program to add declarations or definitions to namespace std
+ or namespaces within namespace std unless otherwise specified. A program may add template
+ specializations for any standard library template to namespace std. Such a specialization
+ (complete or partial) of a standard library template results in undefined behavior unless
+ the declaration depends on a user-defined name of external linkage and unless the
+ specialization meets the standard library requirements for the original template... </p>
+</blockquote>
+
+<p>This implies that it is ok for library users to add specializations, but not
+implementors. A user program can actually detect this, for example, the following manual
+instantiation will not compile if the implementor has made ctype<wchar_t> a
+specialization: </p>
+
+<pre>
+#include <locale>
+#include <wchar.h>
+
+template class std::ctype<wchar_t>; // can't be specialization
+</pre>
+
+<p>
+Lib-7047 Matt Austern comments:
+</p>
+<blockquote>
+<p>The status quo is unclear, and probably contradictory. This issue
+applies both to explicit instantiations and to specializations, since
+it is not permitted to provide both a specialization and an explicit
+instantiation.
+</p>
+<p>
+The specialization issue is actually more serious than the
+instantiation one.
+</p>
+</blockquote>
+
+<p>In Copenhagen, core working group decided on a proposed resolution
+to core issue 259. Under the proposed resolution, it will be legal
+for a translation unit to contain both a specialization and an
+explicit instantiation of the same template, provided that the
+specialization comes first. In such a case, the explicit
+instantiation will be ignored. Further discussion of library issue
+120 assumes that the core 259 resolution will be adopted.</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Option 1.</p>
+<blockquote>
+ <p>Append to 17.4.3.1 paragraph 1: </p>
+ <blockquote>
+ A program may explicitly instantiate any templates in the standard
+ library only if the declaration depends on a user-defined name of
+ external linkage and the instantiation meets the standard library
+ requirements for the original template.
+ </blockquote>
+</blockquote>
+
+<p>Option 2.</p>
+<blockquote>
+ <p>In light of the resolution to core issue 259, no normative changes
+ in the library clauses are necessary. Add the following non-normative
+ note to the end of 17.4.3.1 paragraph 1:</p>
+ <blockquote>
+ [<i>Note:</i> A program may explicitly instantiate standard library
+ templates, even when an explicit instantiation does not depend on
+ a user-defined name. <i>--end note</i>]
+ </blockquote>
+</blockquote>
+
+<p><i>[Copenhagen: LWG discussed three options. (A) Users may not
+explicitly instantiate standard library templates, except on
+user-defined types. Consequence: library implementors may freely
+specialize or instantiate templates. (B) It is implementation defined
+whether users may explicitly instantiate standard library templates on
+non-user-defined types. Consequence: library implementors may freely
+specialize or instantiate templates, but must document the templates
+they have explicitly instantiated. (C) Users may explicitly
+instantiate any standard library template. Consequence: library
+implementors may freely specialize templates, but may not explicitly
+instantiate them. This is a serious burden for implementors; one way
+they can manage it is by defining the standard template as a wrapper,
+and putting all of the real work in an internal helper class/function.
+]</i></p>
+
+<p><i>[Straw poll (first number is favor, second is strongly oppose):
+A - 4, 0; B - 0, 9; C - 9, 1. Proposed resolution 1, above, is
+option A. (It is the original proposed resolution.) Proposed
+resolution 2, above, is option C. Because there was no support
+for option B, no wording is provided.]</i></p>
+<hr>
+<a name="123"><h3>123. Should valarray helper arrays fill functions be const?</h3></a><p>
+<b>Section:</b> 26.3.5.4 <a href="lib-numerics.html#lib.slice.arr.fill"> [lib.slice.arr.fill]</a>, 26.3.7.4 <a href="lib-numerics.html#lib.gslice.array.fill"> [lib.gslice.array.fill]</a>, 26.3.8.4 <a href="lib-numerics.html#lib.mask.array.fill"> [lib.mask.array.fill]</a>, 26.3.9.4 <a href="lib-numerics.html#lib.indirect.array.fill"> [lib.indirect.array.fill]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998 </p>
+<p>One of the operator= in the valarray helper arrays is const and one
+is not. For example, look at slice_array. This operator= in Section
+26.3.5.2 is const: </p>
+
+<p> <tt>void operator=(const valarray<T>&) const;</tt> </p>
+
+<p>but this one in Section 26.3.5.4 is not: </p>
+
+<p> <tt>void operator=(const T&); </tt>
+</p>
+
+<p>The description of the semantics for these two functions is similar. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Make the <tt>operator=(const T&)</tt> versions of slice_array, gslice_array,
+indirect_array, and mask_array <tt>const</tt> member functions. </p>
+
+<p><i>[Dublin: Pete Becker spoke to Daveed Vandevoorde about this and will work on a
+proposed resolution.]</i></p>
+
+<p><i>[Tokyo: Discussed together with the AFNOR paper
+00-0023/N1246. The current helper slices now violate language rules
+due to a core language change (but most compilers don't check, so the
+violation has previously gone undetected). Major surgery is being
+asked for in this and other valarray proposals (see issue <a href="lwg-closed.html#77">77</a>Rationale), and a complete design review is needed before
+making piecemeal changes. Robert Klarer will work on formulating the
+issues.]</i></p>
+<hr>
+<a name="167"><h3>167. Improper use of <tt>traits_type::length()</tt>
+</h3></a><p>
+<b>Section:</b> 27.6.2.5.4 <a href="lib-iostreams.html#lib.ostream.inserters.character"> [lib.ostream.inserters.character]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>Paragraph 4 states that the length is determined using
+<tt>traits::length(s)</tt>. Unfortunately, this function is not
+defined for example if the character type is <tt>wchar_t</tt> and the
+type of <tt>s</tt> is <tt>char const*</tt>. Similar problems exist if
+the character type is <tt>char</tt> and the type of <tt>s</tt> is
+either <tt>signed char const*</tt> or <tt>unsigned char
+const*</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.6.2.5.4 paragraph 4 from:</p>
+<blockquote>
+ <p>Effects: Behaves like an formatted inserter (as described in
+ lib.ostream.formatted.reqmts) of out. After a sentry object is
+ constructed it inserts characters. The number of characters starting
+ at s to be inserted is traits::length(s). Padding is determined as
+ described in lib.facet.num.put.virtuals. The traits::length(s)
+ characters starting at s are widened using out.widen
+ (lib.basic.ios.members). The widened characters and any required
+ padding are inserted into out. Calls width(0).</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>Effects: Behaves like an formatted inserter (as described in
+ lib.ostream.formatted.reqmts) of out. After a sentry object is
+ constructed it inserts characters. The number len of characters
+ starting at s to be inserted is</p>
+ <p>
+ - traits::length((const char*)s) if the second argument is of type
+ const charT*<br>
+ - char_traits<char>::length(s) if the second argument is of
+ type const char*, const signed char*, or const unsigned char* and
+ and charT is not char.<br>
+ </p>
+ <p>Padding is determined as described in
+ lib.facet.num.put.virtuals. The len characters starting at s are
+ widened using out.widen (lib.basic.ios.members). The widened
+ characters and any required padding are inserted into out. Calls
+ width(0).</p>
+</blockquote>
+
+<p><i>[Kona: It is clear to the LWG there is a defect here.
+Dietmar will supply specific wording.]</i></p>
+
+<p><i>[Post-Tokyo: Dietmar supplied the above wording.]</i></p>
+
+<p><i>[Toronto: The original proposed resolution involved
+char_traits<signed char> and char_traits<unsigned char>.
+There was strong opposition to requiring that library implementors
+provide those specializations of char_traits.]</i></p>
+
+<p><i>[Copenhagen: This still isn't quite right: proposed resolution
+text got garbled when the signed char/unsigned char specializations
+were removed. Dietmar will provide revised wording.]</i></p>
+<hr>
+<a name="179"><h3>179. Comparison of const_iterators to iterators doesn't work</h3></a><p>
+<b>Section:</b> 23.1 <a href="lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 2 Jul 1998</p>
+<p>Currently the following will not compile on two well-known standard
+library implementations:</p>
+
+<blockquote>
+ <pre>#include <set>
+using namespace std;
+
+void f(const set<int> &s)
+{
+ set<int>::iterator i;
+ if (i==s.end()); // s.end() returns a const_iterator
+}</pre>
+</blockquote>
+
+<p>
+The reason this doesn't compile is because operator== was implemented
+as a member function of the nested classes set:iterator and
+set::const_iterator, and there is no conversion from const_iterator to
+iterator. Surprisingly, (s.end() == i) does work, though, because of
+the conversion from iterator to const_iterator.
+</p>
+
+<p>
+I don't see a requirement anywhere in the standard that this must
+work. Should there be one? If so, I think the requirement would need
+to be added to the tables in section 24.1.1. I'm not sure about the
+wording. If this requirement existed in the standard, I would think
+that implementors would have to make the comparison operators
+non-member functions.</p>
+
+<p>This issues was also raised on comp.std.c++ by Darin
+Adler. The example given was:</p>
+
+<blockquote>
+ <pre>bool check_equal(std::deque<int>::iterator i,
+std::deque<int>::const_iterator ci)
+{
+return i == ci;
+}</pre>
+</blockquote>
+
+<p>Comment from John Potter:</p>
+<blockquote>
+ <p>
+ In case nobody has noticed, accepting it will break reverse_iterator.
+ </p>
+
+ <p>
+ The fix is to make the comparison operators templated on two types.
+ </p>
+
+ <pre>
+ template <class Iterator1, class Iterator2>
+ bool operator== (reverse_iterator<Iterator1> const& x,
+ reverse_iterator<Iterator2> const& y);
+ </pre>
+
+ <p>
+ Obviously: return x.base() == y.base();
+ </p>
+
+ <p>
+ Currently, no reverse_iterator to const_reverse_iterator compares are
+ valid.
+ </p>
+
+ <p>
+ BTW, I think the issue is in support of bad code. Compares should be
+ between two iterators of the same type. All std::algorithms require
+ the begin and end iterators to be of the same type.
+ </p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>In section 23.1 after paragraph 7 add:</p>
+<blockquote>
+ <p>It is possible to mix <tt>iterator</tt>s and
+ <tt>const_iterator</tt>s in iterator comparison and
+ iterator difference operations.</p>
+</blockquote>
+
+<p><i>[Post-Tokyo: Judy supplied the above wording at the request of
+the LWG.]</i></p>
+
+<p><i>[post-Toronto: Judy supplied a new proposed resolution. The old
+version did not include the words "and iterator
+difference".]</i></p>
+
+<p><i>[Copenhagen: There was some concern that "it is possible
+to mix" might be too informal. Howard and Dave will provide new
+wording, which will involve a list of expressions that are
+guaranteed to be valid.]</i></p>
+<p><b>Rationale:</b></p>
+<p>
+The LWG believes it is clear that the above wording applies only to
+the nested types <tt>X::iterator</tt> and <tt>X::const_iterator</tt>,
+where <tt>X</tt> is a container. There is no requirement that
+<tt>X::reverse_iterator</tt> and <tt>X::const_reverse_iterator</tt>
+can be mixed. If mixing them is considered important, that's a
+separate issue. (Issue <a href="lwg-active.html#280">280</a>.)
+</p>
+<hr>
+<a name="182"><h3>182. Ambiguous references to size_t</h3></a><p>
+<b>Section:</b> 17 <a href="lib-intro.html#lib.library"> [lib.library]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Al Stevens <b>Date:</b> 15 Aug 1999</p>
+<p>Many references to <tt> size_t</tt> throughout the document
+omit the <tt> std::</tt> namespace qualification.</p> <p>For
+example, 17.4.3.4 paragraph 2:</p>
+<blockquote>
+<pre>— operator new(size_t)
+— operator new(size_t, const std::nothrow_t&)
+— operator new[](size_t)
+— operator new[](size_t, const std::nothrow_t&)</pre>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p> In 17.4.3.4 paragraph 2: replace:</p>
+<blockquote>
+<p><tt> - operator new(size_t)<br>
+ - operator new(size_t, const std::nothrow_t&)<br>
+ - operator new[](size_t)<br>
+ - operator new[](size_t, const std::nothrow_t&)</tt></p>
+</blockquote>
+<p> by:</p>
+<blockquote>
+<pre>- operator new(std::size_t)
+- operator new(std::size_t, const std::nothrow_t&)
+- operator new[](std::size_t)
+- operator new[](std::size_t, const std::nothrow_t&)</pre>
+</blockquote>
+<p>In [lib.allocator.requirements] 20.1.5, paragraph 4: replace:</p>
+<blockquote>
+ <p>The typedef members pointer, const_pointer, size_type, and difference_type
+ are required to be T*, T const*, size_t, and ptrdiff_t, respectively.</p>
+</blockquote>
+<p> by:</p>
+<blockquote>
+ <p>The typedef members pointer, const_pointer, size_type, and difference_type
+ are required to be T*, T const*, std::size_t, and std::ptrdiff_t,
+ respectively.</p>
+</blockquote>
+<p>In [lib.allocator.members] 20.4.1.1, paragraphs 3 and 6: replace:</p>
+<blockquote>
+ <p>3 Notes: Uses ::operator new(size_t) (18.4.1).</p>
+ <p>6 Note: the storage is obtained by calling ::operator new(size_t), but it
+ is unspecified when or how often this function is called. The use of hint is
+ unspecified, but intended as an aid to locality if an implementation so
+ desires.</p>
+</blockquote>
+<p>by:</p>
+<blockquote>
+ <p>3 Notes: Uses ::operator new(std::size_t) (18.4.1).</p>
+ <p>6 Note: the storage is obtained by calling ::operator new(std::size_t), but
+ it is unspecified when or how often this function is called. The use of hint
+ is unspecified, but intended as an aid to locality if an implementation so
+ desires.</p>
+</blockquote>
+<p>In [lib.char.traits.require] 21.1.1, paragraph 1: replace:</p>
+<blockquote>
+ <p>In Table 37, X denotes a Traits class defining types and functions for the
+ character container type CharT; c and d denote values of type CharT; p and q
+ denote values of type const CharT*; s denotes a value of type CharT*; n, i and
+ j denote values of type size_t; e and f denote values of type X::int_type; pos
+ denotes a value of type X::pos_type; and state denotes a value of type X::state_type.</p>
+</blockquote>
+<p>by:</p>
+<blockquote>
+ <p>In Table 37, X denotes a Traits class defining types and functions for the
+ character container type CharT; c and d denote values of type CharT; p and q
+ denote values of type const CharT*; s denotes a value of type CharT*; n, i and
+ j denote values of type std::size_t; e and f denote values of type X::int_type;
+ pos denotes a value of type X::pos_type; and state denotes a value of type X::state_type.</p>
+</blockquote>
+<p>In [lib.char.traits.require] 21.1.1, table 37: replace the return type of
+X::length(p): "size_t" by "std::size_t".</p>
+<p> In [lib.std.iterator.tags] 24.3.3, paragraph 2: replace:<br>
+ typedef ptrdiff_t difference_type;<br>
+ by:<br>
+ typedef std::ptrdiff_t difference_type;</p>
+<p> In [lib.locale.ctype] 22.2.1.1 put namespace std { ...} around the declaration of template <class charT> class ctype.<br>
+<br>
+ In [lib.iterator.traits] 24.3.1, paragraph 2 put namespace std { ...} around the declaration of:<br>
+<br>
+ template<class Iterator> struct iterator_traits<br>
+ template<class T> struct iterator_traits<T*><br>
+ template<class T> struct iterator_traits<const T*></p>
+<p><b>Rationale:</b></p>
+<p>The LWG believes correcting names like <tt>size_t</tt> and
+<tt>ptrdiff_t</tt> to <tt>std::size_t</tt> and <tt>std::ptrdiff_t</tt>
+to be essentially editorial. There there can't be another size_t or
+ptrdiff_t meant anyway because, according to 17.4.3.1.4 ,</p>
+
+<blockquote>
+For each type T from the Standard C library, the types ::T and std::T
+are reserved to the implementation and, when defined, ::T shall be
+identical to std::T.
+</blockquote>
+
+<p>The issue is treated as a Defect Report to make explicit the Project
+Editor's authority to make this change.</p>
+
+<p><i>[Post-Tokyo: Nico Josuttis provided the above wording at the
+request of the LWG.]</i></p>
+
+<p><i>[Toronto: This is tangentially related to issue <a href="lwg-active.html#229">229</a>, but only tangentially: the intent of this issue is to
+address use of the name <tt>size_t</tt> in contexts outside of
+namespace std, such as in the description of <tt>::operator new</tt>.
+The proposed changes should be reviewed to make sure they are
+correct.]</i></p>
+
+<p><i>[pre-Copenhagen: Nico has reviewed the changes and believes
+them to be correct.]</i></p>
+
+<hr>
+<a name="187"><h3>187. iter_swap underspecified</h3></a><p>
+<b>Section:</b> 25.2.2 <a href="lib-algorithms.html#lib.alg.swap"> [lib.alg.swap]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 14 Aug 1999</p>
+<p>The description of iter_swap in 25.2.2 paragraph 7,says that it ``exchanges the values''
+of the objects to which two iterators refer.<br>
+<br>
+What it doesn't say is whether it does so using swap or using the assignment operator and copy constructor.<br>
+<br>
+This question is an important one to answer, because swap is specialized to work efficiently for standard containers.<br>
+For example:</p>
+<blockquote>
+<pre>vector<int> v1, v2;
+iter_swap(&v1, &v2);</pre>
+</blockquote>
+<p>Is this call to iter_swap equivalent to calling swap(v1, v2)? Or is it equivalent to</p>
+<blockquote>
+<pre>{
+vector<int> temp = v1;
+v1 = v2;
+v2 = temp;
+}</pre>
+</blockquote>
+<p>The first alternative is O(1); the second is O(n).</p>
+<p>A LWG member, Dave Abrahams, comments:</p>
+<blockquote>
+<p>Not an objection necessarily, but I want to point out the cost of that requirement:</p>
+ <blockquote>
+<p><tt>iter_swap(list<T>::iterator, list<T>::iterator)</tt></p>
+ </blockquote>
+<p>can currently be specialized to be more efficient than iter_swap(T*,T*) for many T (by using splicing). Your proposal would make that optimization
+illegal. </p>
+</blockquote>
+
+<p><i>[Kona: The LWG notes the original need for iter_swap was proxy iterators
+which are no longer permitted.]</i></p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the effect clause of iter_swap in 25.2.2 paragraph 7 from:</p>
+<blockquote>
+<p>Exchanges the values pointed to by the two iterators a and b.</p>
+</blockquote>
+<p>to</p>
+<blockquote>
+<p>
+<tt>swap(*a, *b)</tt>.</p>
+</blockquote>
+
+<p><i>[post-Toronto: The LWG is concerned about possible
+overspecification: there may be cases, such as Dave Abrahams's example
+above, and such as vector<bool>'s iterators, where it makes more
+sense for iter_swap to do something other than swap. If performance
+is a concern, it may be better to have explicit complexity
+requirements than to say how iter_swap should be implemented.]</i></p>
+<hr>
+<a name="197"><h3>197. max_size() underspecified</h3></a><p>
+<b>Section:</b> 20.1.5 <a href="lib-utilities.html#lib.allocator.requirements"> [lib.allocator.requirements]</a>, 23.1 <a href="lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Andy Sawyer <b>Date:</b> 21 Oct 1999</p>
+<p>Must the value returned by max_size() be unchanged from call to call? </p>
+
+<p>Must the value returned from max_size() be meaningful? </p>
+
+<p>Possible meanings identified in lib-6827: </p>
+
+<p>1) The largest container the implementation can support given "best
+case" conditions - i.e. assume the run-time platform is "configured to
+the max", and no overhead from the program itself. This may possibly
+be determined at the point the library is written, but certainly no
+later than compile time.<br>
+<br>
+2) The largest container the program could create, given "best case"
+conditions - i.e. same platform assumptions as (1), but take into
+account any overhead for executing the program itself. (or, roughly
+"storage=storage-sizeof(program)"). This does NOT include any resource
+allocated by the program. This may (or may not) be determinable at
+compile time.<br>
+<br>
+3) The largest container the current execution of the program could
+create, given knowledge of the actual run-time platform, but again,
+not taking into account any currently allocated resource. This is
+probably best determined at program start-up.<br>
+<br>
+4) The largest container the current execution program could create at
+the point max_size() is called (or more correctly at the point
+max_size() returns :-), given it's current environment (i.e. taking
+into account the actual currently available resources). This,
+obviously, has to be determined dynamically each time max_size() is
+called. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 20.1.5 table 32 max_size() wording from:<br>
+<br>
+ the largest value that can meaningfully be
+passed to X::allocate<br>
+to:<br>
+ the value of the largest constant expression
+(5.19 ) that could ever meaningfully be passed to X::allocate</p>
+
+<p>
+Change 23.1 table 65 max_size() wording from:<br>
+<br>
+ size() of the largest possible container.<br>
+to:<br>
+ the value of the largest constant expression
+(5.19 ) that could ever meaningfully be returned by X::size().
+</p>
+
+<p><i>[Kona: The LWG informally discussed this and asked Andy Sawyer to submit
+an issue.]</i></p>
+
+<p><i>[Tokyo: The LWG believes (1) above is the intended meaning.]</i></p>
+
+<p><i>[Post-Tokyo: Beman Dawes supplied the above resolution at the
+request of the LWG. 21.3.3 was not changed because it
+references max_size() in 23.1. The term "compile-time" was
+avoided because it is not defined anywhere in the standard (even
+though it is used several places in the library clauses).]</i></p>
+
+<p><i>[Copenhagen: Exactly what <tt>max_size</tt> means is still
+unclear. It may have a different meaning as a container member
+function than as an allocator member function. For the latter,
+it is probably best thought of as an architectural limit.
+Nathan will provide new wording.]</i></p>
+<hr>
+<a name="198"><h3>198. Validity of pointers and references unspecified after iterator destruction</h3></a><p>
+<b>Section:</b> 24.1 <a href="lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Beman Dawes <b>Date:</b> 3 Nov 1999</p>
+<p>
+Is a pointer or reference obtained from an iterator still valid after
+destruction of the iterator?
+</p>
+<p>
+Is a pointer or reference obtained from an iterator still valid after the value
+of the iterator changes?
+</p>
+<blockquote>
+<pre>
+#include <iostream>
+#include <vector>
+#include <iterator>
+
+int main()
+{
+ typedef std::vector<int> vec_t;
+ vec_t v;
+ v.push_back( 1 );
+
+ // Is a pointer or reference obtained from an iterator still
+ // valid after destruction of the iterator?
+ int * p = &*v.begin();
+ std::cout << *p << '\n'; // OK?
+
+ // Is a pointer or reference obtained from an iterator still
+ // valid after the value of the iterator changes?
+ vec_t::iterator iter( v.begin() );
+ p = &*iter++;
+ std::cout << *p << '\n'; // OK?
+
+ return 0;
+}
+</pre>
+</blockquote>
+
+<p>The standard doesn't appear to directly address these
+questions. The standard needs to be clarified. At least two real-world
+cases have been reported where library implementors wasted
+considerable effort because of the lack of clarity in the
+standard. The question is important because requiring pointers and
+references to remain valid has the effect for practical purposes of
+prohibiting iterators from pointing to cached rather than actual
+elements of containers.</p>
+
+<p>The standard itself assumes that pointers and references obtained
+from an iterator are still valid after iterator destruction or
+change. The definition of reverse_iterator::operator*(), 24.4.1.3.3 , which returns a reference, defines
+effects:</p>
+
+<blockquote>
+ <pre>Iterator tmp = current;
+return *--tmp;</pre>
+</blockquote>
+<p>The definition of reverse_iterator::operator->(), 24.4.1.3.4 , which returns a pointer, defines effects:</p>
+<blockquote>
+ <pre>return &(operator*());</pre>
+</blockquote>
+
+<p>Because the standard itself assumes pointers and references remain
+valid after iterator destruction or change, the standard should say so
+explicitly. This will also reduce the chance of user code breaking
+unexpectedly when porting to a different standard library
+implementation.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add a new paragraph to 24.1 :</p>
+<blockquote>
+Destruction of an iterator may invalidate pointers and references
+previously obtained from that iterator.
+</blockquote>
+
+<p>Replace paragraph 1 of 24.4.1.3.3 with:</p>
+
+<blockquote>
+<p><b>Effects:</b></p>
+<pre>
+ this->tmp = current;
+ --this->tmp;
+ return *this->tmp;
+</pre>
+
+<p>
+[<i>Note:</i> This operation must use an auxiliary member variable,
+rather than a temporary variable, to avoid returning a reference that
+persists beyond the lifetime of its associated iterator. (See
+24.1 .) The name of this member variable is shown for
+exposition only. <i>--end note</i>]
+</p>
+</blockquote>
+
+<p><i>[Tokyo: The LWG reformulated the question purely in terms of
+iterators. The answer to the question is "no, pointers and references
+don't remain valid after iterator destruction." PJP explained that
+implementors use considerable care to avoid such ephemeral pointers and
+references. Several LWG members said that they thought that the standard
+did not actually specify the lifetime of pointers and references obtained from
+iterators, except possibly input iterators.]</i></p>
+
+<p><i>[Post-Tokyo: The issue has been reformulated purely
+in terms of iterators.]</i></p>
+
+<p><i>[Pre-Toronto: Steve Cleary pointed out the no-invalidation
+assumption by reverse_iterator. The issue and proposed resolution was
+reformulated yet again to reflect this reality.]</i></p>
+
+<p><i>[Copenhagen: Andy Koenig pointed out that it is possible to
+rewrite reverse_iterator so that it no longer makes this assumption.
+However, this issue is related to issue <a href="lwg-active.html#299">299</a>. If we
+decide it is intentional that <tt>p[n]</tt> may return by value
+instead of reference when <tt>p</tt> is a Random Access Iterator, then
+other changes in reverse_iterator will be necessary.]</i></p>
+<hr>
+<a name="200"><h3>200. Forward iterator requirements don't allow constant iterators</h3></a><p>
+<b>Section:</b> 24.1.3 <a href="lib-iterators.html#lib.forward.iterators"> [lib.forward.iterators]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 19 Nov 1999</p>
+<p>
+In table 74, the return type of the expression <tt>*a</tt> is given
+as <tt>T&</tt>, where <tt>T</tt> is the iterator's value type.
+For constant iterators, however, this is wrong. ("Value type"
+is never defined very precisely, but it is clear that the value type
+of, say, <tt>std::list<int>::const_iterator</tt> is supposed to be
+<tt>int</tt>, not <tt>const int</tt>.)
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In table 74, change the <b>return type</b> column for <tt>*a</tt>
+from "<tt>T&</tt>" to "<tt>T&</tt> if
+<tt>X</tt> is mutable, otherwise <tt>const T&</tt>".
+</p>
+
+<p><i>[Tokyo: The LWG believes this is the tip of a larger iceberg;
+there are multiple const problems with the STL portion of the library
+and that these should be addressed as a single package. Note
+that issue <a href="lwg-closed.html#180">180</a> has already been declared NAD Future for
+that very reason.]</i></p>
+<hr>
+<a name="201"><h3>201. Numeric limits terminology wrong</h3></a><p>
+<b>Section:</b> 18.2.1 <a href="lib-support.html#lib.limits"> [lib.limits]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Stephen Cleary <b>Date:</b> 21 Dec 1999</p>
+<p>
+In some places in this section, the terms "fundamental types" and
+"scalar types" are used when the term "arithmetic types" is intended.
+The current usage is incorrect because void is a fundamental type and
+pointers are scalar types, neither of which should have
+specializations of numeric_limits.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 18.2 [lib.support.limits] para 1 from:</p>
+<blockquote>
+
+<p> The headers <limits>, <climits>, and <cfloat> supply characteristics of implementation-dependent fundamental types (3.9.1).</p>
+</blockquote>
+
+<p>to:</p>
+<blockquote>
+
+<p> The headers <limits>, <climits>, and <cfloat> supply characteristics of implementation-dependent arithmetic types (3.9.1).</p>
+</blockquote>
+
+<p>Change 18.2.1 [lib.limits] para 1 from:</p>
+<blockquote>
+
+<p> The numeric_limits component provides a C++ program with information about various properties of the implementation's representation of the fundamental
+types.</p>
+</blockquote>
+
+<p>to:</p>
+<blockquote>
+
+<p> The numeric_limits component provides a C++ program with information about various properties of the implementation's representation of the arithmetic
+types.</p>
+</blockquote>
+
+<p>Change 18.2.1 [lib.limits] para 2 from:</p>
+<blockquote>
+
+<p> Specializations shall be provided for each fundamental type. . .</p>
+</blockquote>
+
+<p>to:</p>
+<blockquote>
+
+<p> Specializations shall be provided for each arithmetic type. . .</p>
+</blockquote>
+
+<p>Change 18.2.1 [lib.limits] para 4 from:</p>
+<blockquote>
+
+<p> Non-fundamental standard types. . .</p>
+</blockquote>
+
+<p>to:</p>
+<blockquote>
+
+<p> Non-arithmetic standard types. . .</p>
+</blockquote>
+
+<p>Change 18.2.1.1 [lib.numeric.limits] para 1 from:</p>
+<blockquote>
+
+<p> The member is_specialized makes it possible to distinguish between fundamental types, which have specializations, and non-scalar types, which
+do not.</p>
+</blockquote>
+
+<p>to:</p>
+<blockquote>
+
+<p> The member is_specialized makes it possible to distinguish between arithmetic types, which have specializations, and non-arithmetic types,
+which do not.</p>
+</blockquote>
+
+<p><i>[post-Toronto: The opinion of the LWG is that the wording in the
+standard, as well as the wording of the proposed resolution, is
+flawed. The term "arithmetic types" is well defined in C
+and C++, and it is not clear that the term is being used correctly.
+It is also not clear that the term "implementation
+dependent" has any useful meaning in this context. The biggest
+problem is that numeric_limits seems to be intended both for built-in
+types and for user-defined types, and the standard doesn't make it
+clear how numeric_limits applies to each of those cases. A wholesale
+review of numeric_limits is needed. A paper would be welcome.]</i></p>
+<hr>
+<a name="202"><h3>202. unique() effects unclear when predicate not an equivalence relation</h3></a><p>
+<b>Section:</b> 25.2.8 <a href="lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 13 Jan 2000</p>
+<p>
+What should unique() do if you give it a predicate that is not an
+equivalence relation? There are at least two plausible answers:
+</p>
+
+<blockquote>
+
+<p>
+ 1. You can't, because 25.2.8 says that it it "eliminates all but
+ the first element from every consecutive group of equal
+ elements..." and it wouldn't make sense to interpret "equal" as
+ meaning anything but an equivalence relation. [It also doesn't
+ make sense to interpret "equal" as meaning ==, because then there
+ would never be any sense in giving a predicate as an argument at
+ all.]
+</p>
+
+<p>
+ 2. The word "equal" should be interpreted to mean whatever the
+ predicate says, even if it is not an equivalence relation
+ (and in particular, even if it is not transitive).
+</p>
+
+</blockquote>
+
+<p>
+The example that raised this question is from Usenet:
+</p>
+
+<blockquote>
+
+<pre>int f[] = { 1, 3, 7, 1, 2 };
+int* z = unique(f, f+5, greater<int>());</pre>
+
+</blockquote>
+
+<p>
+If one blindly applies the definition using the predicate
+greater<int>, and ignore the word "equal", you get:
+</p>
+
+<blockquote>
+
+<p>
+ Eliminates all but the first element from every consecutive group
+ of elements referred to by the iterator i in the range [first, last)
+ for which *i > *(i - 1).
+</p>
+
+</blockquote>
+
+<p>
+The first surprise is the order of the comparison. If we wanted to
+allow for the predicate not being an equivalence relation, then we
+should surely compare elements the other way: pred(*(i - 1), *i). If
+we do that, then the description would seem to say: "Break the
+sequence into subsequences whose elements are in strictly increasing
+order, and keep only the first element of each subsequence". So the
+result would be 1, 1, 2. If we take the description at its word, it
+would seem to call for strictly DEcreasing order, in which case the
+result should be 1, 3, 7, 2.<br>
+<br>
+In fact, the SGI implementation of unique() does neither: It yields 1,
+3, 7.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Options:</p>
+<blockquote>
+ <p> 1. Impose an explicit requirement that the predicate be an
+ equivalence relation. </p>
+ <p> 2. Drop the word "equal" from the description to make it clear that
+ the intent is to compare pairs of adjacent elements, and
+ change pred(*i, *(i - 1)) to pred(*(i - 1), i).</p>
+ <p> 3. Change the effects to:</p>
+ <blockquote>
+ Effects: Eliminates all but the first element e from
+ every consecutive group of elements referred to by the
+ iterator i in the range [first, last) for which the
+ following corresponding conditions hold: e == *i or
+ pred(e,*i) != false.
+ </blockquote>
+</blockquote>
+<p>A LWG member, Nico Josuttis, comments:</p>
+<p>First, I agree that the current wording is simply wrong. However, to follow
+all [known] current implementations I propose [option 3 above].</p>
+
+<p><i>[ Tokyo: The issue was discussed at length without reaching
+consensus. Straw vote: Option 1 - preferred by 2 people. Option 2 -
+preferred by 0 people. Option 3 - preferred by 3 people. Many
+abstentions. ]</i></p>
+
+<p><i>[Copenhagen: There was some support for all options. The option
+with the least support was 1 (one person in favor), and the option
+with the most support was 2 (seven in favor). One person was strongly
+opposed to option 1, and one person was strongly opposed to the
+variation on option 2 in which the order of arguments would remain
+pred(*i, *(i - 1)).]</i></p>
+<hr>
+<a name="225"><h3>225. std:: algorithms use of other unqualified algorithms</h3></a><p>
+<b>Section:</b> 17.4.4.3 <a href="lib-intro.html#lib.global.functions"> [lib.global.functions]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 01 Apr 2000</p>
+<p>Are algorithms in std:: allowed to use other algorithms without qualification, so functions in
+user namespaces might be found through Koenig lookup?</p>
+<p>For example, a popular standard library implementation includes this
+implementation of std::unique:</p>
+<blockquote>
+<pre>namespace std {
+ template <class _ForwardIter>
+ _ForwardIter unique(_ForwardIter __first, _ForwardIter __last) {
+ __first = adjacent_find(__first, __last);
+ return unique_copy(__first, __last, __first);
+ }
+ }</pre>
+</blockquote>
+<p>Imagine two users on opposite sides of town, each using unique on his own
+sequences bounded by my_iterators . User1 looks at his standard library
+implementation and says, "I know how to implement a more efficient
+unique_copy for my_iterators", and writes:</p>
+<blockquote>
+<pre>namespace user1 {
+ class my_iterator;
+ // faster version for my_iterator
+ my_iterator unique_copy(my_iterator, my_iterator, my_iterator);
+ }</pre>
+</blockquote>
+<p>user1::unique_copy() is selected by Koenig lookup, as he intended.</p>
+<p>User2 has other needs, and writes:</p>
+<blockquote>
+<pre>namespace user2 {
+ class my_iterator;
+ // Returns true iff *c is a unique copy of *a and *b.
+ bool unique_copy(my_iterator a, my_iterator b, my_iterator c);
+ }</pre>
+</blockquote>
+<p>User2 is shocked to find later that his fully-qualified use of
+std::unique(user2::my_iterator, user2::my_iterator, user2::my_iterator) fails to
+compile (if he's lucky). Looking in the standard, he sees the following Effects
+clause for unique():</p>
+<blockquote>
+ <p>Effects: Eliminates all but the first element from every consecutive group
+ of equal elements referred to by the iterator i in the range [first, last) for
+ which the following corresponding conditions hold: *i == *(i - 1) or pred(*i,
+ *(i - 1)) != false</p>
+</blockquote>
+<p>The standard gives user2 absolutely no reason to think he can interfere with
+std::unique by defining names in namespace user2. His standard library has been
+built with the template export feature, so he is unable to inspect the
+implementation. User1 eventually compiles his code with another compiler, and
+his version of unique_copy silently stops being called. Eventually, he realizes
+that he was depending on an implementation detail of his library and had no
+right to expect his unique_copy() to be called portably.</p>
+<p>On the face of it, and given above scenario, it may seem obvious that the
+implementation of unique() shown is non-conforming because it uses unique_copy()
+rather than ::std::unique_copy(). Most standard library implementations,
+however, seem to disagree with this notion.</p>
+<p> <i>[Tokyo: Steve Adamczyk from
+the core working group indicates that "std::" is sufficient;
+leading "::" qualification is not required because any namespace
+qualification is sufficient to suppress Koenig lookup.]</i>
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add a paragraph and a note at the end of
+17.4.4.3 :</p>
+<blockquote>
+
+<p>Unless otherwise specified, no global or non-member function in the
+standard library shall use a function from another namespace which is
+found through <i>argument-dependent name lookup</i> (3.4.2 ).</p>
+
+<p>[Note: the phrase "unless otherwise specified" is intended to
+allow Koenig lookup in cases like that of ostream_iterators:<br>
+
+<br>
+ Effects:</p>
+ <blockquote>
+<p>*out_stream << value;<br>
+ if(delim != 0) *out_stream << delim;<br>
+ return (*this);</p>
+ <p>--end note]</p>
+ </blockquote>
+</blockquote>
+
+<p><i>[Tokyo: The LWG agrees that this is a defect in the standard, but
+is as yet unsure if the proposed resolution is the best
+solution. Furthermore, the LWG believes that the same problem of
+unqualified library names applies to wording in the standard itself,
+and has opened issue <a href="lwg-active.html#229">229</a> accordingly. Any resolution of
+issue <a href="lwg-active.html#225">225</a> should be coordinated with the resolution of
+issue <a href="lwg-active.html#229">229</a>.]</i></p>
+
+<p><i>[Toronto: The LWG is not sure if this is a defect in the
+standard. Most LWG members believe that an implementation of
+<tt>std::unique</tt> like the one quoted in this issue is already
+illegal, since, under certain circumstances, its semantics are not
+those specified in the standard. The standard's description of
+<tt>unique</tt> does not say that overloading <tt>adjacent_find</tt>
+should have any effect.]</i></p>
+<hr>
+<a name="226"><h3>226. User supplied specializations or overloads of namespace std function templates</h3></a><p>
+<b>Section:</b> 17.4.3.1 <a href="lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 01 Apr 2000</p>
+<p>The issues are: </p>
+<p>1. How can a 3rd party library implementor (lib1) write a version of a standard
+algorithm which is specialized to work with his own class template? </p>
+<p>2. How can another library implementor (lib2) write a generic algorithm which
+will take advantage of the specialized algorithm in lib1?</p>
+<p>This appears to be the only viable answer under current language rules:</p>
+<blockquote>
+ <pre>namespace lib1
+{
+ // arbitrary-precision numbers using T as a basic unit
+ template <class T>
+ class big_num { //...
+ };
+ </pre>
+ <pre> // defining this in namespace std is illegal (it would be an
+ // overload), so we hope users will rely on Koenig lookup
+ template <class T>
+ void swap(big_int<T>&, big_int<T>&);
+}</pre>
+ <pre>#include <algorithm>
+namespace lib2
+{
+ template <class T>
+ void generic_sort(T* start, T* end)
+ {
+ ...
+ // using-declaration required so we can work on built-in types
+ using std::swap;
+ // use Koenig lookup to find specialized algorithm if available
+ swap(*x, *y);
+ }
+}</pre>
+</blockquote>
+<p>This answer has some drawbacks. First of all, it makes writing lib2 difficult
+and somewhat slippery. The implementor needs to remember to write the
+using-declaration, or generic_sort will fail to compile when T is a built-in
+type. The second drawback is that the use of this style in lib2 effectively
+"reserves" names in any namespace which defines types which may
+eventually be used with lib2. This may seem innocuous at first when applied to
+names like swap, but consider more ambiguous names like unique_copy() instead.
+It is easy to imagine the user wanting to define these names differently in his
+own namespace. A definition with semantics incompatible with the standard
+library could cause serious problems (see issue <a href="lwg-active.html#225">225</a>).</p>
+<p>Why, you may ask, can't we just partially specialize std::swap()? It's
+because the language doesn't allow for partial specialization of function
+templates. If you write:</p>
+<blockquote>
+ <pre>namespace std
+{
+ template <class T>
+ void swap(lib1::big_int<T>&, lib1::big_int<T>&);
+}</pre>
+</blockquote>
+<p>You have just overloaded std::swap, which is illegal under the current
+language rules. On the other hand, the following full specialization is legal:</p>
+<blockquote>
+ <pre>namespace std
+{
+ template <>
+ void swap(lib1::other_type&, lib1::other_type&);
+}</pre>
+</blockquote>
+
+<p>This issue reflects concerns raised by the "Namespace issue
+with specialized swap" thread on comp.lang.c++.moderated. A
+similar set of concerns was earlier raised on the boost.org mailing
+list and the ACCU-general mailing list. Also see library reflector
+message c++std-lib-7354.</p>
+
+<p><b>Proposed resolution:</b></p>
+
+<p><i>[Tokyo: Summary, "There is no conforming way to extend
+std::swap for user defined templates." The LWG agrees that
+there is a problem. Would like more information before
+proceeding. This may be a core issue. Core issue 229 has been opened
+to discuss the core aspects of this problem. It was also noted that
+submissions regarding this issue have been received from several
+sources, but too late to be integrated into the issues list.
+]</i></p>
+
+<p><i>[Post-Tokyo: A paper with several proposed resolutions,
+J16/00-0029==WG21/N1252, "Shades of namespace std functions
+" by Alan Griffiths, is in the Post-Tokyo mailing. It
+should be considered a part of this issue.]</i></p>
+
+<p><i>[Toronto: Dave Abrahams and Peter Dimov have proposed a
+resolution that involves core changes: it would add partial
+specialization of function template. The Core Working Group is
+reluctant to add partial specialization of function templates. It is
+viewed as a large change, CWG believes that proposal presented leaves
+some syntactic issues unanswered; if the CWG does add partial
+specialization of function templates, it wishes to develop its own
+proposal. The LWG continues to believe that there is a serious
+problem: there is no good way for users to force the library to use
+user specializations of generic standard library functions, and in
+certain cases (e.g. transcendental functions called by
+<tt>valarray</tt> and <tt>complex</tt>) this is important. Koenig
+lookup isn't adequate, since names within the library must be
+qualified with <tt>std</tt> (see issue 225), specialization doesn't
+work (we don't have partial specialization of function templates), and
+users aren't permitted to add overloads within namespace std.
+]</i></p>
+
+<p><i>[Copenhagen: Discussed at length, with no consensus. Relevant
+papers in the pre-Copenhagen mailing: N1289, N1295, N1296. Discussion
+focused on four options. (1) Relax restrictions on overloads within
+namespace std. (2) Mandate that the standard library use unqualified
+calls for <tt>swap</tt> and possibly other functions. (3) Introduce
+helper class templates for <tt>swap</tt> and possibly other functions.
+(4) Introduce partial specialization of function templates. Every
+option had both support and opposition. Straw poll (first number is
+support, second is strongly opposed): (1) 6, 4; (2) 6, 7; (3) 3, 8;
+(4) 4, 4.]</i></p>
+<hr>
+<a name="228"><h3>228. Incorrect specification of "..._byname" facets</h3></a><p>
+<b>Section:</b> 22.2 <a href="lib-locales.html#lib.locale.categories"> [lib.locale.categories]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Apr 2000</p>
+<p>The sections 22.2.1.2 , 22.2.1.4 ,
+22.2.1.6 , 22.2.3.2 , 22.2.4.2 , 22.2.5.4 , 22.2.6.4 , and 22.2.7.2 overspecify the
+definitions of the "..._byname" classes by listing a bunch
+of virtual functions. At the same time, no semantics of these
+functions are defined. Real implementations do not define these
+functions because the functional part of the facets is actually
+implemented in the corresponding base classes and the constructor of
+the "..._byname" version just provides suitable date used by
+these implementations. For example, the 'numpunct' methods just return
+values from a struct. The base class uses a statically initialized
+struct while the derived version reads the contents of this struct
+from a table. However, no virtual function is defined in
+'numpunct_byname'.</p>
+
+<p>For most classes this does not impose a problem but specifically
+for 'ctype' it does: The specialization for 'ctype_byname<char>'
+is required because otherwise the semantics would change due to the
+virtual functions defined in the general version for 'ctype_byname':
+In 'ctype<char>' the method 'do_is()' is not virtual but it is
+made virtual in both 'ctype<cT>' and 'ctype_byname<cT>'.
+Thus, a class derived from 'ctype_byname<char>' can tell whether
+this class is specialized or not under the current specification:
+Without the specialization, 'do_is()' is virtual while with
+specialization it is not virtual.</p>
+<p><b>Proposed resolution:</b></p>
+<p> Change section 22.2.1.2 (lib.locale.ctype.byname) to become:</p>
+<pre> namespace std {
+ template <class charT>
+ class ctype_byname : public ctype<charT> {
+ public:
+ typedef ctype<charT>::mask mask;
+ explicit ctype_byname(const char*, size_t refs = 0);
+ protected:
+ ~ctype_byname(); // virtual
+ };
+ }</pre>
+<p> Change section 22.2.1.6 (lib.locale.codecvt.byname) to become:</p>
+<pre> namespace std {
+ template <class internT, class externT, class stateT>
+ class codecvt_byname : public codecvt<internT, externT, stateT> {
+ public:
+ explicit codecvt_byname(const char*, size_t refs = 0);
+ protected:
+ ~codecvt_byname(); // virtual
+ };
+ }
+</pre>
+<p> Change section 22.2.3.2 (lib.locale.numpunct.byname) to become:</p>
+<pre> namespace std {
+ template <class charT>
+ class numpunct_byname : public numpunct<charT> {
+ // this class is specialized for char and wchar_t.
+ public:
+ typedef charT char_type;
+ typedef basic_string<charT> string_type;
+ explicit numpunct_byname(const char*, size_t refs = 0);
+ protected:
+ ~numpunct_byname(); // virtual
+ };
+ }</pre>
+<p> Change section 22.2.4.2 (lib.locale.collate.byname) to become:</p>
+<pre> namespace std {
+ template <class charT>
+ class collate_byname : public collate<charT> {
+ public:
+ typedef basic_string<charT> string_type;
+ explicit collate_byname(const char*, size_t refs = 0);
+ protected:
+ ~collate_byname(); // virtual
+ };
+ }</pre>
+<p> Change section 22.2.5.2 (lib.locale.time.get.byname) to become:</p>
+<pre> namespace std {
+ template <class charT, class InputIterator = istreambuf_iterator<charT> >
+ class time_get_byname : public time_get<charT, InputIterator> {
+ public:
+ typedef time_base::dateorder dateorder;
+ typedef InputIterator iter_type</pre>
+<pre> explicit time_get_byname(const char*, size_t refs = 0);
+ protected:
+ ~time_get_byname(); // virtual
+ };
+ }</pre>
+<p> Change section 22.2.5.4 (lib.locale.time.put.byname) to become:</p>
+<pre> namespace std {
+ template <class charT, class OutputIterator = ostreambuf_iterator<charT> >
+ class time_put_byname : public time_put<charT, OutputIterator>
+ {
+ public:
+ typedef charT char_type;
+ typedef OutputIterator iter_type;</pre>
+<pre> explicit time_put_byname(const char*, size_t refs = 0);
+ protected:
+ ~time_put_byname(); // virtual
+ };
+ }"</pre>
+<p> Change section 22.2.6.4 (lib.locale.moneypunct.byname) to become:</p>
+<pre> namespace std {
+ template <class charT, bool Intl = false>
+ class moneypunct_byname : public moneypunct<charT, Intl> {
+ public:
+ typedef money_base::pattern pattern;
+ typedef basic_string<charT> string_type;</pre>
+<pre> explicit moneypunct_byname(const char*, size_t refs = 0);
+ protected:
+ ~moneypunct_byname(); // virtual
+ };
+ }</pre>
+<p> Change section 22.2.7.2 (lib.locale.messages.byname) to become:</p>
+<pre> namespace std {
+ template <class charT>
+ class messages_byname : public messages<charT> {
+ public:
+ typedef messages_base::catalog catalog;
+ typedef basic_string<charT> string_type;</pre>
+<pre> explicit messages_byname(const char*, size_t refs = 0);
+ protected:
+ ~messages_byname(); // virtual
+ };
+ }</pre>
+<p>Remove section 22.2.1.4 completely (because in
+this case only those members are defined to be virtual which are
+defined to be virtual in 'ctype<cT>'.)</p>
+
+<p><i>[Post-Tokyo: Dietmar Kühl submitted this issue at the request of
+the LWG to solve the underlying problems raised by issue <a href="lwg-closed.html#138">138</a>.]</i></p>
+
+<p><i>[Copenhagen: proposed resolution was revised slightly, to remove
+three last virtual functions from <tt>messages_byname</tt>.]</i></p>
+
+<hr>
+<a name="229"><h3>229. Unqualified references of other library entities</h3></a><p>
+<b>Section:</b> 17.4.1.1 <a href="lib-intro.html#lib.contents"> [lib.contents]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 19 Apr 2000</p>
+<p>Throughout the library chapters, the descriptions of library entities refer
+to other library entities without necessarily qualifying the names.</p>
+
+<p>For example, section 25.2.2 "Swap" describes the effect of
+swap_ranges in terms of the unqualified name "swap". This section
+could reasonably be interpreted to mean that the library must be implemented so
+as to do a lookup of the unqualified name "swap", allowing users to
+override any ::std::swap function when Koenig lookup applies.</p>
+
+<p>Although it would have been best to use explicit qualification with
+"::std::" throughout, too many lines in the standard would have to be
+adjusted to make that change in a Technical Corrigendum.</p>
+
+<p>Issue <a href="lwg-active.html#182">182</a>, which addresses qualification of
+<tt>size_t</tt>, is a special case of this.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>To section 17.4.1.1 "Library contents" Add the following paragraph:</p>
+<blockquote>
+ <p>Whenever a name x defined in the standard library is mentioned, the name x
+ is assumed to be fully qualified as ::std::x, unless explicitly described
+ otherwise. For example, if the Effects section for library function F is
+ described as calling library function G, the function ::std::G is meant.</p>
+</blockquote>
+
+<p><i>[Post-Tokyo: Steve Clamage submitted this issue at the request of
+the LWG to solve a problem in the standard itself similar to the
+problem within implementations of library identified by issue <a href="lwg-active.html#225">225</a>. Any resolution of issue <a href="lwg-active.html#225">225</a> should be
+coordinated with the resolution of this issue.]</i></p>
+
+<p><i>[post-Toronto: Howard is undecided about whether it is
+appropriate for all standard library function names referred to in
+other standard library functions to be explicitly qualified by
+<tt>std</tt>: it is common advice that users should define global
+functions that operate on their class in the same namespace as the
+class, and this requires argument-dependent lookup if those functions
+are intended to be called by library code. Several LWG members are
+concerned that valarray appears to require argument-dependent lookup,
+but that the wording may not be clear enough to fall under
+"unless explicitly described otherwise".]</i></p>
+<hr>
+<a name="230"><h3>230. Assignable specified without also specifying CopyConstructible</h3></a><p>
+<b>Section:</b> 17 <a href="lib-intro.html#lib.library"> [lib.library]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Beman Dawes <b>Date:</b> 26 Apr 2000</p>
+<p>Issue <a href="lwg-defects.html#227">227</a> identified an instance (std::swap) where
+Assignable was specified without also specifying
+CopyConstructible. The LWG asked that the standard be searched to
+determine if the same defect existed elsewhere.</p>
+
+<p>There are a number of places (see proposed resolution below) where
+Assignable is specified without also specifying
+CopyConstructible. There are also several cases where both are
+specified. For example, 26.4.1 .</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 23.1 table 65 for value_type:
+change "T is Assignable" to "T is CopyConstructible and
+Assignable"
+</p>
+
+<p>In 23.1.2 table 69 X::key_type; change
+"Key is Assignable" to "Key is
+CopyConstructible and Assignable"<br>
+</p>
+
+<p>In 24.1.2 paragraph 1, change:
+</p>
+<blockquote>
+<p> A class or a built-in type X satisfies the requirements of an
+output iterator if X is an Assignable type (23.1) and also the
+following expressions are valid, as shown in Table 73:
+</p>
+</blockquote>
+<p>to:
+</p>
+<blockquote>
+<p> A class or a built-in type X satisfies the requirements of an
+output iterator if X is a CopyConstructible (20.1.3) and Assignable
+type (23.1) and also the following expressions are valid, as shown in
+Table 73:
+</p>
+</blockquote>
+
+<p><i>[Post-Tokyo: Beman Dawes submitted this issue at the request of
+the LWG. He asks that the 25.2.4 and 25.2.5 changes be studied carefully, as it is not clear that
+CopyConstructible is really a requirement and may be
+overspecification.]</i></p>
+<p><b>Rationale:</b></p>
+<p>The original proposed resolution also included changes to input
+iterator, fill, and replace. The LWG believes that those changes are
+not necessary. The LWG considered some blanket statement, where an
+Assignable type was also required to be Copy Constructible, but
+decided against this because fill and replace really don't require the
+Copy Constructible property.</p>
+<hr>
+<a name="231"><h3>231. Precision in iostream?</h3></a><p>
+<b>Section:</b> 22.2.2.2.2 <a href="lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> James Kanze, Stephen Clamage <b>Date:</b> 25 Apr 2000</p>
+<p>What is the following program supposed to output?</p>
+<pre>#include <iostream>
+
+ int
+ main()
+ {
+ std::cout.setf( std::ios::scientific , std::ios::floatfield ) ;
+ std::cout.precision( 0 ) ;
+ std::cout << 1.23 << '\n' ;
+ return 0 ;
+ }</pre>
+<p>From my C experience, I would expect "1e+00"; this is what
+<tt>printf("%.0e" , 1.23 );</tt> does. G++ outputs
+"1.000000e+00".</p>
+
+<p>The only indication I can find in the standard is 22.2.2.2.2/11,
+where it says "For conversion from a floating-point type, if
+(flags & fixed) != 0 or if str.precision() > 0, then
+str.precision() is specified in the conversion specification."
+This is an obvious error, however, fixed is not a mask for a field,
+but a value that a multi-bit field may take -- the results of and'ing
+fmtflags with ios::fixed are not defined, at least not if
+ios::scientific has been set. G++'s behavior corresponds to what might
+happen if you do use (flags & fixed) != 0 with a typical
+implementation (floatfield == 3 << something, fixed == 1
+<< something, and scientific == 2 << something).</p>
+
+<p>Presumably, the intent is either (flags & floatfield) != 0, or
+(flags & floatfield) == fixed; the first gives something more or
+less like the effect of precision in a printf floating point
+conversion. Only more or less, of course. In order to implement printf
+formatting correctly, you must know whether the precision was
+explicitly set or not. Say by initializing it to -1, instead of 6, and
+stating that for floating point conversions, if precision < -1, 6
+will be used, for fixed point, if precision < -1, 1 will be used,
+etc. Plus, of course, if precision == 0 and flags & floatfield ==
+0, 1 should be = used. But it probably isn't necessary to emulate all
+of the anomalies of printf:-).</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In 22.2.2.2.2 , paragraph 11, change
+"if <tt>(flags & fixed) != 0</tt>" to
+"if <tt>(flags & floatfield) == fixed ||
+ (flags & floatfield) == scientific</tt>"
+</p>
+<p><b>Rationale:</b></p>
+<p>The floatfield determines whether numbers are formatted as if
+with %f, %e, or %g. If the <tt>fixed</tt> bit is set, it's %f,
+if <tt>scientific</tt> it's %e, and if both bits are set, or
+neither, it's %e.</p>
+<p>Turning to the C standard, a precision of 0 is meaningful
+for %f and %e, but not for %g: for %g, precision 0 is taken
+to be the same as precision 1.</p>
+<p>The proposed resolution has the effect that the output of
+the above program will be "1e+00".</p>
+<hr>
+<a name="232"><h3>232. "depends" poorly defined in 17.4.3.1</h3></a><p>
+<b>Section:</b> 17.4.3.1 <a href="lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Peter Dimov <b>Date:</b> 18 Apr 2000</p>
+<p>17.4.3.1/1 uses the term "depends" to limit the set of allowed
+specializations of standard templates to those that "depend on a
+user-defined name of external linkage."</p>
+<p>This term, however, is not adequately defined, making it possible to
+construct a specialization that is, I believe, technically legal according to
+17.4.3.1/1, but that specializes a standard template for a built-in type such as
+'int'.</p>
+<p>The following code demonstrates the problem:</p>
+<blockquote>
+ <pre>#include <algorithm></pre>
+ <pre>template<class T> struct X
+{
+ typedef T type;
+};</pre>
+ <pre>namespace std
+{
+ template<> void swap(::X<int>::type& i, ::X<int>::type& j);
+}</pre>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>Change "user-defined name" to "user-defined
+type".</p>
+<p><b>Rationale:</b></p>
+<p>This terminology is used in section 2.5.2 and 4.1.1 of <i>The C++
+Programming Language</i>. It disallows the example in the issue,
+since the underlying type itself is not user-defined. The only
+possible problem I can see is for non-type templates, but there's no
+possible way for a user to come up with a specialization for bitset,
+for example, that might not have already been specialized by the
+implementor?</p>
+
+<p><i>[Toronto: this may be related to issue <a href="lwg-active.html#120">120</a>.]</i></p>
+
+<p><i>[post-Toronto: Judy provided the above proposed resolution and
+rationale.]</i></p>
+<hr>
+<a name="233"><h3>233. Insertion hints in associative containers</h3></a><p>
+<b>Section:</b> 23.1.2 <a href="lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 30 Apr 2000</p>
+<p>
+If <tt>mm</tt> is a multimap and <tt>p</tt> is an iterator
+into the multimap, then <tt>mm.insert(p, x)</tt> inserts
+<tt>x</tt> into <tt>mm</tt> with <tt>p</tt> as a hint as
+to where it should go. Table 69 claims that the execution time is
+amortized constant if the insert winds up taking place adjacent to
+<tt>p</tt>, but does not say when, if ever, this is guaranteed to
+happen. All it says it that <tt>p</tt> is a hint as to where to
+insert.
+</p>
+<p>
+The question is whether there is any guarantee about the relationship
+between <tt>p</tt> and the insertion point, and, if so, what it
+is.
+</p>
+<p>
+I believe the present state is that there is no guarantee: The user
+can supply <tt>p</tt>, and the implementation is allowed to
+disregard it entirely.
+</p>
+<p><b>Proposed resolution:</b></p>
+
+<p>
+General Idea (Andrew Koenig):
+t is inserted at the point closest to (the point immediately
+ahead of) p. That would give the user a way of controlling the order
+in which elements appear that have equal keys. Doing so would be
+particularly easy in two cases that I suspect are common:
+</p>
+<pre>
+ mm.insert(mm.begin(), t); // inserts as first element of set of equal keys
+ mm.insert(mm.end(), t); // inserts as last element of set of equal keys
+</pre>
+
+<p>
+These examples would allow t to be inserted at the beginning and end,
+respectively, of the set of elements with the same key as t.
+</p>
+
+<p>
+assertion/note/pre/postcondition in table 69<br>
+Change:
+</p>
+<blockquote>
+iterator p is a hint pointing to where the insert should start to search.
+</blockquote>
+<p>To:</p>
+<blockquote>
+if t is inserted, p is used as follows: insert t right before p
+if possible; otherwise, if p is equal to a.end(), or if the key value
+of t is greater than the key value of *p, t is inserted just before
+a.lowerbound(the key value of t); otherwise, t is inserted right
+before a.upperbound(the key value of t).
+</blockquote>
+<p>complexity:<br>
+Change:</p>
+<blockquote>right after p</blockquote>
+<p>To:</p>
+<blockquote>right before p</blockquote>
+
+<p>
+Thus making:<br>
+assertion/note/pre/postcondition:
+</p>
+<blockquote>
+inserts t if and only if there is no element with key equivalent to
+the key of t in containers with unique keys; always inserts t in
+containers with equivalent keys. always returns the iterator pointing
+to the element with key equivalent to the key of t.
+if t is inserted, p is used as follows: insert t right before p
+if possible; otherwise, if p is equal to a.end(), or if the key value
+of t is greater than the key value of *p, t is inserted just before
+a.lowerbound(the key value of t); otherwise, t is inserted right
+before a.upperbound(the key value of t).
+<br>NON-NORMATIVE FOOTNOTE:
+| This gives the user a way of controlling the order
+| in which elements appear that have equal keys. Doing this is
+| particularly easy in two common cases:
+<pre>
+| mm.insert(mm.begin(), t); // inserts as first element of set of equal keys
+| mm.insert(mm.end(), t); // inserts as last element of set of equal keys
+</pre>
+<br>END-FOOTNOTE
+</blockquote>
+
+<p>complexity:</p>
+<blockquote>
+logarithmic in general, but amortized constant if t is inserted right
+before p.
+</blockquote>
+
+<p><i>[Toronto: there was general agreement that this is a real defect:
+when inserting an element x into a multiset that already contains
+several copies of x, there is no way to know whether the hint will be
+used. There was some support for an alternative resolution: we check
+on both sides of the hint (both before and after, in that order). If
+either is the correct location, the hint is used; otherwise it is not.
+This would be different from the original proposed resolution, because
+in the proposed resolution the hint will be used even if it is very
+far from the insertion point. JC van Winkel supplied precise wording
+for both options.]</i></p>
+
+<p><i>[Copenhagen: the LWG looked at both options, and preferred the
+original. This preference is contingent on seeing a reference
+implementation showing that it is possible to implement this
+requirement without loss of efficiency.]</i></p>
+
+<hr>
+<a name="235"><h3>235. No specification of default ctor for reverse_iterator</h3></a><p>
+<b>Section:</b> 24.4.1.1 <a href="lib-iterators.html#lib.reverse.iterator"> [lib.reverse.iterator]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 24 Apr 2000</p>
+<p>The declaration of <tt>reverse_iterator</tt> lists a default
+constructor. However, no specification is given what this constructor
+should do.</p>
+<p><b>Proposed resolution:</b></p>
+ <p>In section 24.4.1.3.1 add the following
+ paragraph:</p>
+ <blockquote>
+ <p><tt>reverse_iterator()</tt></p>
+
+ <p>Default initializes <tt>current</tt>. Iterator operations
+ applied to the resulting iterator have defined behavior if and
+ only if the corresponding operations are defined on a default
+ constructed iterator of type <tt>Iterator</tt>.</p>
+ </blockquote>
+ <p><i>[pre-Copenhagen: Dietmar provide wording for proposed
+ resolution.]</i></p>
+<hr>
+<a name="238"><h3>238. Contradictory results of stringbuf initialization.</h3></a><p>
+<b>Section:</b> 27.7.1.1 <a href="lib-iostreams.html#lib.stringbuf.cons"> [lib.stringbuf.cons]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 11 May 2000</p>
+<p>In 27.7.1.1 paragraph 4 the results of calling the constructor of
+'basic_stringbuf' are said to be <tt>str() == str</tt>. This is fine
+that far but consider this code:</p>
+
+<pre>
+ std::basic_stringbuf<char> sbuf("hello, world", std::ios_base::openmode(0));
+ std::cout << "'" << sbuf.str() << "'\n";
+</pre>
+
+<p>Paragraph 3 of 27.7.1.1 basically says that in this case neither
+the output sequence nor the input sequence is initialized and
+paragraph 2 of 27.7.1.2 basically says that <tt>str()</tt> either
+returns the input or the output sequence. None of them is initialized,
+ie. both are empty, in which case the return from <tt>str()</tt> is
+defined to be <tt>basic_string<cT>()</tt>.</p>
+
+<p>However, probably only test cases in some testsuites will detect this
+"problem"...</p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove 27.7.1.1 paragraph 4.</p>
+<p><b>Rationale:</b></p>
+<p>We could fix 27.7.1.1 paragraph 4, but there would be no point. If
+we fixed it, it would say just the same thing as text that's already
+in the standard.</p>
+<hr>
+<a name="239"><h3>239. Complexity of unique() and/or unique_copy incorrect</h3></a><p>
+<b>Section:</b> 25.2.8 <a href="lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> May 15 2000</p>
+<p>The complexity of unique and unique_copy are inconsistent with each
+other and inconsistent with the implementations. The standard
+specifies:</p>
+
+<p>for unique():</p>
+
+<blockquote>-3- Complexity: If the range (last - first) is not empty, exactly
+(last - first) - 1 applications of the corresponding predicate, otherwise
+no applications of the predicate.</blockquote>
+
+<p>for unique_copy():</p>
+
+<blockquote>-7- Complexity: Exactly last - first applications of the corresponding
+predicate.</blockquote>
+
+<p>
+The implementations do it the other way round: unique() applies the
+predicate last-first times and unique_copy() applies it last-first-1
+times.</p>
+
+<p>As both algorithms use the predicate for pair-wise comparison of
+sequence elements I don't see a justification for unique_copy()
+applying the predicate last-first times, especially since it is not
+specified to which pair in the sequence the predicate is applied
+twice.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change both complexity sections in 25.2.8 to:</p>
+
+<blockquote>Complexity: Exactly last - first - 1 applications of the
+corresponding predicate.</blockquote>
+
+<p><i>[Toronto: This is related to issue <a href="lwg-active.html#202">202</a>. We can't
+specify <tt>unique</tt>'s complexity until we decide what
+<tt>unique</tt> is supposed to do.]</i></p>
+<hr>
+<a name="240"><h3>240. Complexity of adjacent_find() is meaningless</h3></a><p>
+<b>Section:</b> 25.1.5 <a href="lib-algorithms.html#lib.alg.adjacent.find"> [lib.alg.adjacent.find]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> May 15 2000</p>
+<p>The complexity section of adjacent_find is defective:</p>
+
+<blockquote>
+<pre>
+template <class ForwardIterator>
+ForwardIterator adjacent_find(ForwardIterator first, ForwardIterator last
+ BinaryPredicate pred);
+</pre>
+
+<p>-1- Returns: The first iterator i such that both i and i + 1 are in
+the range [first, last) for which the following corresponding
+conditions hold: *i == *(i + 1), pred(*i, *(i + 1)) != false. Returns
+last if no such iterator is found.</p>
+
+<p>-2- Complexity: Exactly find(first, last, value) - first applications
+of the corresponding predicate.
+</p>
+</blockquote>
+
+<p>In the Complexity section, it is not defined what "value"
+is supposed to mean. My best guess is that "value" means an
+object for which one of the conditions pred(*i,value) or
+pred(value,*i) is true, where i is the iterator defined in the Returns
+section. However, the value type of the input sequence need not be
+equality-comparable and for this reason the term find(first, last,
+value) - first is meaningless.</p>
+
+<p>A term such as find_if(first, last, bind2nd(pred,*i)) - first or
+find_if(first, last, bind1st(pred,*i)) - first might come closer to
+the intended specification. Binders can only be applied to function
+objects that have the function call operator declared const, which is
+not required of predicates because they can have non-const data
+members. For this reason, a specification using a binder could only be
+an "as-if" specification.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the complexity section in 25.1.5 to:</p>
+<blockquote>
+For a nonempty range, exactly <tt>min((<i>i</i> - <i>first</i>) + 1,
+(<i>last</i> - <i>first</i>) - 1)</tt> applications of the
+corresponding predicate, where <i>i</i> is <tt>adjacent_find</tt>'s
+return value.
+</blockquote>
+
+<p><i>[Copenhagen: the original resolution specified an upper
+bound. The LWG preferred an exact count.]</i></p>
+
+<hr>
+<a name="241"><h3>241. Does unique_copy() require CopyConstructible and Assignable?</h3></a><p>
+<b>Section:</b> 25.2.8 <a href="lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> May 15 2000</p>
+
+<p>Some popular implementations of unique_copy() create temporary
+copies of values in the input sequence, at least if the input iterator
+is a pointer. Such an implementation is built on the assumption that
+the value type is CopyConstructible and Assignable.</p>
+
+<p>It is common practice in the standard that algorithms explicitly
+specify any additional requirements that they impose on any of the
+types used by the algorithm. An example of an algorithm that creates
+temporary copies and correctly specifies the additional requirements
+is accumulate(), 26.4.1 .</p>
+
+<p>Since the specifications of unique() and unique_copy() do not
+require CopyConstructible and Assignable of the InputIterator's value
+type the above mentioned implementations are not standard-compliant. I
+cannot judge whether this is a defect in the standard or a defect in
+the implementations.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 25.2.8 change:</p>
+
+<blockquote>
+-4- Requires: The ranges [first, last) and [result, result+(last-first))
+shall not overlap.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+-4- Requires: The ranges [first, last) and [result, result+(last-first))
+shall not overlap. The expression *result = *first is valid.
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>
+Creating temporary copies is unavoidable, since the arguments may be
+input iterators; this implies that the value type must be copy
+constructible. However, we don't need to say this explicitly; it's
+already implied by table 72 in 24.1.1. We don't precisely want to say
+that the input iterator's value type <tt>T</tt> must be assignable,
+because we never quite use that property. We assign through the
+output iterator. The output iterator might have a different value
+type, or no value type; it might not use <tt>T</tt>'s assignment
+operator. If it's an <tt>ostream_iterator</tt>, for example, then
+we'll use <tt>T</tt>'s operator<< but not its assignment
+operator.
+</p>
+<hr>
+<a name="242"><h3>242. Side effects of function objects</h3></a><p>
+<b>Section:</b> 25.2.3 <a href="lib-algorithms.html#lib.alg.transform"> [lib.alg.transform]</a>, 26.4 <a href="lib-numerics.html#lib.numeric.ops"> [lib.numeric.ops]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> May 15 2000</p>
+<p>The algorithms transform(), accumulate(), inner_product(),
+partial_sum(), and adjacent_difference() require that the function
+object supplied to them shall not have any side effects.</p>
+
+<p>The standard defines a side effect in 1.9 as:</p>
+<blockquote>-7- Accessing an object designated by a volatile lvalue (basic.lval),
+modifying an object, calling a library I/O function, or calling a function
+that does any of those operations are all side effects, which are changes
+in the state of the execution environment.</blockquote>
+
+<p>As a consequence, the function call operator of a function object supplied
+to any of the algorithms listed above cannot modify data members, cannot
+invoke any function that has a side effect, and cannot even create and
+modify temporary objects. It is difficult to imagine a function object
+that is still useful under these severe limitations. For instance, any
+non-trivial transformator supplied to transform() might involve creation
+and modification of temporaries, which is prohibited according to the current
+wording of the standard.</p>
+
+<p>On the other hand, popular implementations of these algorithms exhibit
+uniform and predictable behavior when invoked with a side-effect-producing
+function objects. It looks like the strong requirement is not needed for
+efficient implementation of these algorithms.</p>
+
+<p>The requirement of side-effect-free function objects could be
+replaced by a more relaxed basic requirement (which would hold for all
+function objects supplied to any algorithm in the standard library):</p>
+<blockquote>A function objects supplied to an algorithm shall not invalidate
+any iterator or sequence that is used by the algorithm. Invalidation of
+the sequence includes destruction of the sorting order if the algorithm
+relies on the sorting order (see section 25.3 - Sorting and related operations
+[lib.alg.sorting]).</blockquote>
+
+<p>I can't judge whether it is intended that the function objects supplied
+to transform(), accumulate(), inner_product(), partial_sum(), or adjacent_difference()
+shall not modify sequence elements through dereferenced iterators.</p>
+
+<p>It is debatable whether this issue is a defect or a change request.
+Since the consequences for user-supplied function objects are drastic and
+limit the usefulness of the algorithms significantly I would consider it
+a defect.</p>
+<p><b>Proposed resolution:</b></p>
+
+<p><i>Things to notice about these changes:</i></p>
+
+<ol>
+<li> <i>The fully-closed ("[]" as opposed to half-closed "[)" ranges
+ are intentional. we want to prevent side-effects from
+ invalidating the end iterators.</i>
+</li>
+
+<li> <i>That has the unintentional side-effect of prohibiting
+ modification of the end element as a side-effect. This could
+ conceivably be significant in some cases.</i>
+</li>
+
+<li> <i>The wording also prevents side-effects from modifying elements
+ of the output sequence. I can't imagine why anyone would want
+ to do this, but it is arguably a restriction that implementors
+ don't need to place on users.</i>
+</li>
+
+<li> <i>Lifting the restrictions imposed in #2 and #3 above is possible
+ and simple, but would require more verbiage.</i>
+</li>
+</ol>
+
+<p>Change 25.2.3/2 from:</p>
+
+<blockquote>
+ -2- Requires: op and binary_op shall not have any side effects.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -2- Requires: in the ranges [first1, last1], [first2, first2 +
+ (last1 - first1)] and [result, result + (last1- first1)], op and
+ binary_op shall neither modify elements nor invalidate iterators or
+ subranges.
+ [Footnote: The use of fully closed ranges is intentional --end footnote]
+</blockquote>
+
+
+<p>Change 25.2.3/2 from:</p>
+
+<blockquote>
+ -2- Requires: op and binary_op shall not have any side effects.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -2- Requires: op and binary_op shall not invalidate iterators or
+ subranges, or modify elements in the ranges [first1, last1],
+ [first2, first2 + (last1 - first1)], and [result, result + (last1
+ - first1)].
+ [Footnote: The use of fully closed ranges is intentional --end footnote]
+</blockquote>
+
+
+<p>Change 26.4.1/2 from:</p>
+
+<blockquote>
+ -2- Requires: T must meet the requirements of CopyConstructible
+ (lib.copyconstructible) and Assignable (lib.container.requirements)
+ types. binary_op shall not cause side effects.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -2- Requires: T must meet the requirements of CopyConstructible
+ (lib.copyconstructible) and Assignable
+ (lib.container.requirements) types. In the range [first, last],
+ binary_op shall neither modify elements nor invalidate iterators
+ or subranges.
+ [Footnote: The use of a fully closed range is intentional --end footnote]
+</blockquote>
+
+<p>Change 26.4.2/2 from:</p>
+
+<blockquote>
+ -2- Requires: T must meet the requirements of CopyConstructible
+ (lib.copyconstructible) and Assignable (lib.container.requirements)
+ types. binary_op1 and binary_op2 shall not cause side effects.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -2- Requires: T must meet the requirements of CopyConstructible
+ (lib.copyconstructible) and Assignable (lib.container.requirements)
+ types. In the ranges [first, last] and [first2, first2 + (last -
+ first)], binary_op1 and binary_op2 shall neither modify elements
+ nor invalidate iterators or subranges.
+ [Footnote: The use of fully closed ranges is intentional --end footnote]
+</blockquote>
+
+
+<p>Change 26.4.3/4 from:</p>
+
+<blockquote>
+ -4- Requires: binary_op is expected not to have any side effects.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -4- Requires: In the ranges [first, last] and [result, result +
+ (last - first)], binary_op shall neither modify elements nor
+ invalidate iterators or subranges.
+ [Footnote: The use of fully closed ranges is intentional --end footnote]
+</blockquote>
+
+<p>Change 26.4.4/2 from:</p>
+
+<blockquote>
+ -2- Requires: binary_op shall not have any side effects.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -2- Requires: In the ranges [first, last] and [result, result +
+ (last - first)], binary_op shall neither modify elements nor
+ invalidate iterators or subranges.
+ [Footnote: The use of fully closed ranges is intentional --end footnote]
+</blockquote>
+
+<p><i>[Toronto: Dave Abrahams supplied wording.]</i></p>
+
+<p><i>[Copenhagen: Proposed resolution was modified slightly. Matt
+added footnotes pointing out that the use of closed ranges was
+intentional.]</i></p>
+
+<hr>
+<a name="247"><h3>247. <tt>vector</tt>, <tt>deque::insert</tt> complexity</h3></a><p>
+<b>Section:</b> 23.2.4.3 <a href="lib-containers.html#lib.vector.modifiers"> [lib.vector.modifiers]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Lisa Lippincott <b>Date:</b> 06 June 2000</p>
+<p>Paragraph 2 of 23.2.4.3 [lib.vector.modifiers] describes the complexity
+of <tt>vector::insert</tt>:</p>
+
+ <blockquote>
+ Complexity: If first and last are forward iterators, bidirectional
+ iterators, or random access iterators, the complexity is linear in
+ the number of elements in the range [first, last) plus the distance
+ to the end of the vector. If they are input iterators, the complexity
+ is proportional to the number of elements in the range [first, last)
+ times the distance to the end of the vector.
+ </blockquote>
+
+<p>First, this fails to address the non-iterator forms of
+<tt>insert</tt>.</p>
+
+<p>Second, the complexity for input iterators misses an edge case --
+it requires that an arbitrary number of elements can be added at
+the end of a <tt>vector</tt> in constant time.</p>
+
+<p>At the risk of strengthening the requirement, I suggest simply</p>
+
+ <blockquote>
+ Complexity: The complexity is linear in the number of elements
+ inserted plus the distance to the end of the vector.
+ </blockquote>
+
+<p>For input iterators, one may achieve this complexity by first
+inserting at the end of the <tt>vector</tt>, and then using
+<tt>rotate</tt>.</p>
+
+<p>I looked to see if <tt>deque</tt> had a similar problem, and was
+surprised to find that <tt>deque</tt> places no requirement on the
+complexity of inserting multiple elements (23.2.1.3 ,
+paragraph 3):</p>
+
+ <blockquote>
+ Complexity: In the worst case, inserting a single element into a
+ deque takes time linear in the minimum of the distance from the
+ insertion point to the beginning of the deque and the distance
+ from the insertion point to the end of the deque. Inserting a
+ single element either at the beginning or end of a deque always
+ takes constant time and causes a single call to the copy constructor
+ of T.
+ </blockquote>
+
+<p>I suggest:</p>
+
+ <blockquote>
+ Complexity: The complexity is linear in the number of elements
+ inserted plus the shorter of the distances to the beginning and
+ end of the deque. Inserting a single element at either the
+ beginning or the end of a deque causes a single call to the copy
+ constructor of T.
+ </blockquote>
+<p><b>Proposed resolution:</b></p>
+
+<p><i>[Toronto: It's agreed that there is a defect in complexity of
+multi-element insert for vector and deque. For vector, the complexity
+should probably be something along the lines of <tt>c<sub>1</sub> * N
++ c<sub>2</sub> * distance(i, end())</tt>. However, there is some
+concern about whether it is reasonable to amortize away the copies
+that we get from a reallocation whenever we exceed the vector's
+capacity. For deque, the situation is somewhat less clear. Deque is
+notoriously complicated, and we may not want to impose complexity
+requirements that would imply any implementation technique more
+complicated than a while loop whose body is a single-element
+insert.]</i></p>
+<hr>
+<a name="250"><h3>250. splicing invalidates iterators</h3></a><p>
+<b>Section:</b> 23.2.2.4 <a href="lib-containers.html#lib.list.ops"> [lib.list.ops]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Brian Parker <b>Date:</b> 14 Jul 2000</p>
+<p>
+Section 23.2.2.4 [lib.list.ops] states that
+</p>
+<pre>
+ void splice(iterator position, list<T, Allocator>& x);
+</pre>
+<p>
+<i>invalidates</i> all iterators and references to list <tt>x</tt>.
+</p>
+
+<p>
+This is unnecessary and defeats an important feature of splice. In
+fact, the SGI STL guarantees that iterators to <tt>x</tt> remain valid
+after <tt>splice</tt>.
+</p>
+<p><b>Proposed resolution:</b></p>
+
+<p>Add a footnote to 23.2.2.4 , paragraph 1:</p>
+<blockquote>
+[<i>Footnote:</i> As specified in 20.1.5 , paragraphs
+4-5, the semantics described in this clause applies only to the case
+where allocators compare equal. --end footnote]
+</blockquote>
+
+<p>In 23.2.2.4 , replace paragraph 4 with:</p>
+<blockquote>
+Effects: Inserts the contents of x before position and x becomes
+empty. Pointers and references to the moved elements of x now refer to
+those same elements but as members of *this. Iterators referring to the
+moved elements will continue to refer to their elements, but they now
+behave as iterators into *this, not into x.
+</blockquote>
+
+<p>In 23.2.2.4 , replace paragraph 7 with:</p>
+<blockquote>
+Effects: Inserts an element pointed to by i from list x before
+position and removes the element from x. The result is unchanged if
+position == i or position == ++i. Pointers and references to *i continue
+to refer to this same element but as a member of *this. Iterators to *i
+(including i itself) continue to refer to the same element, but now
+behave as iterators into *this, not into x.
+</blockquote>
+
+<p>In 23.2.2.4 , replace paragraph 12 with:</p>
+<blockquote>
+Requires: [first, last) is a valid range in x. The result is
+undefined if position is an iterator in the range [first, last).
+Pointers and references to the moved elements of x now refer to those
+same elements but as members of *this. Iterators referring to the moved
+elements will continue to refer to their elements, but they now behave as
+iterators into *this, not into x.
+</blockquote>
+
+<p><i>[pre-Copenhagen: Howard provided wording.]</i></p>
+<p><b>Rationale:</b></p>
+<p>The original proposed resolution said that iterators and references
+would remain "valid". The new proposed resolution clarifies what that
+means. Note that this only applies to the case of equal allocators.
+From 20.1.5 paragraph 4, the behavior of list when
+allocators compare nonequal is outside the scope of the standard.</p>
+<hr>
+<a name="253"><h3>253. valarray helper functions are almost entirely useless</h3></a><p>
+<b>Section:</b> 26.3.2.1 <a href="lib-numerics.html#lib.valarray.cons"> [lib.valarray.cons]</a>, 26.3.2.2 <a href="lib-numerics.html#lib.valarray.assign"> [lib.valarray.assign]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Robert Klarer <b>Date:</b> 31 Jul 2000</p>
+<p>This discussion is adapted from message c++std-lib-7056 posted
+November 11, 1999. I don't think that anyone can reasonably claim
+that the problem described below is NAD.</p>
+
+<p>These valarray constructors can never be called:</p>
+
+<pre>
+ template <class T>
+ valarray<T>::valarray(const slice_array<T> &);
+ template <class T>
+ valarray<T>::valarray(const gslice_array<T> &);
+ template <class T>
+ valarray<T>::valarray(const mask_array<T> &);
+ template <class T>
+ valarray<T>::valarray(const indirect_array<T> &);
+</pre>
+
+<p>Similarly, these valarray assignment operators cannot be
+called:</p>
+
+<pre>
+ template <class T>
+ valarray<T> valarray<T>::operator=(const slice_array<T> &);
+ template <class T>
+ valarray<T> valarray<T>::operator=(const gslice_array<T> &);
+ template <class T>
+ valarray<T> valarray<T>::operator=(const mask_array<T> &);
+ template <class T>
+ valarray<T> valarray<T>::operator=(const indirect_array<T> &);
+</pre>
+
+<p>Please consider the following example:</p>
+
+<pre>
+ #include <valarray>
+ using namespace std;
+
+ int main()
+ {
+ valarray<double> va1(12);
+ valarray<double> va2(va1[slice(1,4,3)]); // line 1
+ }
+</pre>
+
+
+<p>Since the valarray va1 is non-const, the result of the sub-expression
+va1[slice(1,4,3)] at line 1 is an rvalue of type const
+std::slice_array<double>. This slice_array rvalue is then used to
+construct va2. The constructor that is used to construct va2 is
+declared like this:</p>
+
+<pre>
+ template <class T>
+ valarray<T>::valarray(const slice_array<T> &);
+</pre>
+
+<p>Notice the constructor's const reference parameter. When the
+constructor is called, a slice_array must be bound to this reference.
+The rules for binding an rvalue to a const reference are in 8.5.3,
+paragraph 5 (see also 13.3.3.1.4). Specifically, paragraph 5
+indicates that a second slice_array rvalue is constructed (in this
+case copy-constructed) from the first one; it is this second rvalue
+that is bound to the reference parameter. Paragraph 5 also requires
+that the constructor that is used for this purpose be callable,
+regardless of whether the second rvalue is elided. The
+copy-constructor in this case is not callable, however, because it is
+private. Therefore, the compiler should report an error.</p>
+
+<p>Since slice_arrays are always rvalues, the valarray constructor that has a
+parameter of type const slice_array<T> & can never be called. The
+same reasoning applies to the three other constructors and the four
+assignment operators that are listed at the beginning of this post.
+Furthermore, since these functions cannot be called, the valarray helper
+classes are almost entirely useless.</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Adopt section 2 of 00-0023/N1246. Sections 1 and 5 of that paper have
+already been classified as "Request for Extension". Sections
+3 and 4 are reasonable generalizations of section 2, but they do not
+resolve an obvious inconsistency in the standard.
+</p>
+
+<p><i>[Toronto: it is agreed that there is a defect. A full
+discussion, and an attempt at fixing the defect, should wait until we
+can hear from valarray experts.]</i></p>
+<hr>
+<a name="254"><h3>254. Exception types in clause 19 are constructed from <tt>std::string</tt>
+</h3></a><p>
+<b>Section:</b> 19.1 <a href="lib-diagnostics.html#lib.std.exceptions"> [lib.std.exceptions]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 01 Aug 2000</p>
+<p>
+Many of the standard exception types which implementations are
+required to throw are constructed with a const std::string&
+parameter. For example:
+</p>
+
+<pre>
+ 19.1.5 Class out_of_range [lib.out.of.range]
+ namespace std {
+ class out_of_range : public logic_error {
+ public:
+ explicit out_of_range(const string& what_arg);
+ };
+ }
+
+ 1 The class out_of_range defines the type of objects thrown as excep-
+ tions to report an argument value not in its expected range.
+
+ out_of_range(const string& what_arg);
+
+ Effects:
+ Constructs an object of class out_of_range.
+ Postcondition:
+ strcmp(what(), what_arg.c_str()) == 0.
+</pre>
+
+<p>
+There are at least two problems with this:
+</p>
+<ol>
+<li>A program which is low on memory may end up throwing
+std::bad_alloc instead of out_of_range because memory runs out while
+constructing the exception object.</li>
+<li>An obvious implementation which stores a std::string data member
+may end up invoking terminate() during exception unwinding because the
+exception object allocates memory (or rather fails to) as it is being
+copied.</li>
+</ol>
+
+<p>
+There may be no cure for (1) other than changing the interface to
+out_of_range, though one could reasonably argue that (1) is not a
+defect. Personally I don't care that much if out-of-memory is reported
+when I only have 20 bytes left, in the case when out_of_range would
+have been reported. People who use exception-specifications might care
+a lot, though.
+</p>
+
+<p>
+There is a cure for (2), but it isn't completely obvious. I think a
+note for implementors should be made in the standard. Avoiding
+possible termination in this case shouldn't be left up to chance. The
+cure is to use a reference-counted "string" implementation
+in the exception object. I am not necessarily referring to a
+std::string here; any simple reference-counting scheme for a NTBS
+would do.
+</p>
+
+<p>
+Further discussion, in email:
+</p>
+
+<p>
+...I'm not so concerned about (1). After all, a library implementation
+can add const char* constructors as an extension, and users don't
+<i>need</i> to avail themselves of the standard exceptions, though this is
+a lame position to be forced into. FWIW, std::exception and
+std::bad_alloc don't require a temporary basic_string.
+</p>
+
+<p>
+...I don't think the fixed-size buffer is a solution to the problem,
+strictly speaking, because you can't satisfy the postcondition
+<br>
+ <tt> strcmp(what(), what_arg.c_str()) == 0</tt>
+<br>
+For all values of what_arg (i.e. very long values). That means that
+the only truly conforming solution requires a dynamic allocation.
+</p>
+<p><b>Proposed resolution:</b></p>
+
+<p><i>[Toronto: some LWG members thought this was merely a QoI issue,
+but most believed that it was at least a borderline defect. There was
+more support for nonnormative advice to implementors than for a
+normative change.]</i></p>
+<hr>
+<a name="258"><h3>258. Missing allocator requirement</h3></a><p>
+<b>Section:</b> 20.1.5 <a href="lib-utilities.html#lib.allocator.requirements"> [lib.allocator.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 22 Aug 2000</p>
+<p>
+From lib-7752:
+</p>
+
+<p>
+I've been assuming (and probably everyone else has been assuming) that
+allocator instances have a particular property, and I don't think that
+property can be deduced from anything in Table 32.
+</p>
+
+<p>
+I think we have to assume that allocator type conversion is a
+homomorphism. That is, if x1 and x2 are of type X, where
+X::value_type is T, and if type Y is X::template
+rebind<U>::other, then Y(x1) == Y(x2) if and only if x1 == x2.
+</p>
+
+<p>
+Further discussion: Howard Hinnant writes, in lib-7757:
+</p>
+
+<p>
+I think I can prove that this is not provable by Table 32. And I agree
+it needs to be true except for the "and only if". If x1 != x2, I see no
+reason why it can't be true that Y(x1) == Y(x2). Admittedly I can't
+think of a practical instance where this would happen, or be valuable.
+But I also don't see a need to add that extra restriction. I think we
+only need:
+</p>
+
+<blockquote>
+ if (x1 == x2) then Y(x1) == Y(x2)
+</blockquote>
+
+<p>
+If we decide that == on allocators is transitive, then I think I can
+prove the above. But I don't think == is necessarily transitive on
+allocators. That is:
+</p>
+
+<p>
+Given x1 == x2 and x2 == x3, this does not mean x1 == x3.
+</p>
+
+<p>Example:</p>
+
+<blockquote>
+<p>
+x1 can deallocate pointers from: x1, x2, x3 <br>
+x2 can deallocate pointers from: x1, x2, x4 <br>
+x3 can deallocate pointers from: x1, x3 <br>
+x4 can deallocate pointers from: x2, x4
+</p>
+
+<p>
+x1 == x2, and x2 == x4, but x1 != x4
+</p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+
+<p><i>[Toronto: LWG members offered multiple opinions. One
+opinion is that it should not be required that <tt>x1 == x2</tt>
+implies <tt>Y(x1) == Y(x2)</tt>, and that it should not even be
+required that <tt>X(x1) == x1</tt>. Another opinion is that
+the second line from the bottom in table 32 already implies the
+desired property. This issue should be considered in light of
+other issues related to allocator instances.]</i></p>
+<hr>
+<a name="259"><h3>259. <tt>basic_string::operator[]</tt> and const correctness</h3></a><p>
+<b>Section:</b> 21.3.4 <a href="lib-strings.html#lib.string.access"> [lib.string.access]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Chris Newton <b>Date:</b> 27 Aug 2000</p>
+<p>
+<i>Paraphrased from a message that Chris Newton posted to comp.std.c++:</i>
+</p>
+
+<p>
+The standard's description of <tt>basic_string<>::operator[]</tt>
+seems to violate const correctness.
+</p>
+
+<p>
+The standard (21.3.4/1) says that "If <tt>pos < size()</tt>,
+returns <tt>data()[pos]</tt>." The types don't work. The
+return value of <tt>data()</tt> is <tt>const charT*</tt>, but
+<tt>operator[]</tt> has a non-const version whose return type is <tt>reference</tt>.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In section 21.3.4, paragraph 1, change
+"<tt>data()[<i>pos</i>]</tt>" to "<tt>*(begin() +
+<i>pos</i>)</tt>".
+</p>
+<hr>
+<a name="264"><h3>264. Associative container <tt>insert(i, j)</tt> complexity requirements are not feasible.</h3></a><p>
+<b>Section:</b> 23.1.2 <a href="lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> John Potter <b>Date:</b> 07 Sep 2000</p>
+<p>
+Table 69 requires linear time if [i, j) is sorted. Sorted is necessary but not sufficient.
+Consider inserting a sorted range of even integers into a set<int> containing the odd
+integers in the same range.
+</p>
+
+<p><i>Related issue: <a href="lwg-closed.html#102">102</a></i></p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In Table 69, in section 23.1.2, change the complexity clause for
+insertion of a range from "N log(size() + N) (N is the distance
+from i to j) in general; linear if [i, j) is sorted according to
+value_comp()" to "N log(size() + N), where N is the distance
+from i to j".
+</p>
+
+<p><i>[Copenhagen: Minor fix in proposed resolution: fixed unbalanced
+parens in the revised wording.]</i></p>
+
+<p><b>Rationale:</b></p>
+<p>
+Testing for valid insertions could be less efficient than simply
+inserting the elements when the range is not both sorted and between
+two adjacent existing elements; this could be a QOI issue.
+</p>
+
+<p>
+The LWG considered two other options: (a) specifying that the
+complexity was linear if [i, j) is sorted according to value_comp()
+and between two adjacent existing elements; or (b) changing to
+Klog(size() + N) + (N - K) (N is the distance from i to j and K is the
+number of elements which do not insert immediately after the previous
+element from [i, j) including the first). The LWG felt that, since
+we can't guarantee linear time complexity whenever the range to be
+inserted is sorted, it's more trouble than it's worth to say that it's
+linear in some special cases.
+</p>
+<hr>
+<a name="266"><h3>266. bad_exception::~bad_exception() missing Effects clause</h3></a><p>
+<b>Section:</b> 18.6.2.1 <a href="lib-support.html#lib.bad.exception"> [lib.bad.exception]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 24 Sep 2000</p>
+<p>
+The synopsis for std::bad_exception lists the function ~bad_exception()
+but there is no description of what the function does (the Effects
+clause is missing).
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Remove the destructor from the class synopses of
+<tt>bad_alloc</tt> (18.4.2.1 ),
+<tt>bad_cast</tt> (18.5.2 ),
+<tt>bad_typeid</tt> (18.5.3 ),
+and <tt>bad_exception</tt> (18.6.2.1 ).
+</p>
+<p><b>Rationale:</b></p>
+<p>
+This is a general problem with the exception classes in clause 18.
+The proposed resolution is to remove the destructors from the class
+synopses, rather than to document the destructors' behavior, because
+removing them is more consistent with how exception classes are
+described in clause 19.
+</p>
+<hr>
+<a name="267"><h3>267. interaction of strstreambuf::overflow() and seekoff()</h3></a><p>
+<b>Section:</b> D.7.1.3 <a href="future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 5 Oct 2000</p>
+<p>
+It appears that the interaction of the strstreambuf members overflow()
+and seekoff() can lead to undefined behavior in cases where defined
+behavior could reasonably be expected. The following program
+demonstrates this behavior:
+</p>
+
+<pre>
+ #include <strstream>
+
+ int main ()
+ {
+ std::strstreambuf sb;
+ sb.sputc ('c');
+
+ sb.pubseekoff (-1, std::ios::end, std::ios::in);
+ return !('c' == sb.sgetc ());
+ }
+</pre>
+
+<p>
+D.7.1.1, p1 initializes strstreambuf with a call to basic_streambuf<>(),
+which in turn sets all pointers to 0 in 27.5.2.1, p1.
+</p>
+
+<p>
+27.5.2.2.5, p1 says that basic_streambuf<>::sputc(c) calls
+overflow(traits::to_int_type(c)) if a write position isn't available (it
+isn't due to the above).
+</p>
+
+<p>
+D.7.1.3, p3 says that strstreambuf::overflow(off, ..., ios::in) makes at
+least one write position available (i.e., it allows the function to make
+any positive number of write positions available).
+</p>
+
+<p>
+D.7.1.3, p13 computes newoff = seekhigh - eback(). In D.7.1, p4 we see
+seekhigh = epptr() ? epptr() : egptr(), or seekhigh = epptr() in this
+case. newoff is then epptr() - eback().
+</p>
+
+<p>
+D.7.1.4, p14 sets gptr() so that gptr() == eback() + newoff + off, or
+gptr() == epptr() + off holds.
+</p>
+
+<p>
+If strstreambuf::overflow() made exactly one write position available
+then gptr() will be set to just before epptr(), and the program will
+return 0. Buf if the function made more than one write position
+available, epptr() and gptr() will both point past pptr() and the
+behavior of the program is undefined.
+</p>
+<p><b>Proposed resolution:</b></p>
+
+
+ <p>Change the last sentence of D.7.1 paragraph 4 from</p>
+
+ <blockquote>
+ Otherwise, seeklow equals gbeg and seekhigh is either pend, if
+ pend is not a null pointer, or gend.
+ </blockquote>
+
+ <p>to become</p>
+
+ <blockquote>
+ Otherwise, seeklow equals gbeg and seekhigh is either gend if
+ 0 == pptr(), or pbase() + max where max is the maximum value of
+ pptr() - pbase() ever reached for this stream.
+ </blockquote>
+
+<p><i>[
+ pre-Copenhagen: Dietmar provided wording for proposed resolution.
+]</i></p>
+
+<p><i>[
+ post-Copenhagen: Fixed a typo: proposed resolution said to fix
+ 4.7.1, not D.7.1.
+]</i></p>
+
+<p><b>Rationale:</b></p>
+<p>Note that this proposed resolution does not require an increase in
+the layout of strstreambuf to maintain max: If overflow() is
+implemented to make exactly one write position available, max ==
+epptr() - pbase() always holds. However, if overflow() makes more than
+one write position available, the number of additional character (or
+some equivalent) has to be stored somewhere.</p>
+<hr>
+<a name="270"><h3>270. Binary search requirements overly strict</h3></a><p>
+<b>Section:</b> 25.3.3 <a href="lib-algorithms.html#lib.alg.binary.search"> [lib.alg.binary.search]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 18 Oct 2000</p>
+<p>
+Each of the four binary search algorithms (lower_bound, upper_bound,
+equal_range, binary_search) has a form that allows the user to pass a
+comparison function object. According to 25.3, paragraph 2, that
+comparison function object has to be a strict weak ordering.
+</p>
+
+<p>
+This requirement is slightly too strict. Suppose we are searching
+through a sequence containing objects of type X, where X is some
+large record with an integer key. We might reasonably want to look
+up a record by key, in which case we would want to write something
+like this:
+</p>
+<pre>
+ struct key_comp {
+ bool operator()(const X& x, int n) const {
+ return x.key() < n;
+ }
+ }
+
+ std::lower_bound(first, last, 47, key_comp());
+</pre>
+
+<p>
+key_comp is not a strict weak ordering, but there is no reason to
+prohibit its use in lower_bound.
+</p>
+
+<p>
+There's no difficulty in implementing lower_bound so that it allows
+the use of something like key_comp. (It will probably work unless an
+implementor takes special pains to forbid it.) What's difficult is
+formulating language in the standard to specify what kind of
+comparison function is acceptable. We need a notion that's slightly
+more general than that of a strict weak ordering, one that can encompass
+a comparison function that involves different types. Expressing that
+notion may be complicated.
+</p>
+
+<p><i>Additional questions raised at the Toronto meeting:</i></p>
+<ul>
+<li> Do we really want to specify what ordering the implementor must
+ use when calling the function object? The standard gives
+ specific expressions when describing these algorithms, but it also
+ says that other expressions (with different argument order) are
+ equivalent.</li>
+<li> If we are specifying ordering, note that the standard uses both
+ orderings when describing <tt>equal_range</tt>.</li>
+<li> Are we talking about requiring these algorithms to work properly
+ when passed a binary function object whose two argument types
+ are not the same, or are we talking about requirements when
+ they are passed a binary function object with several overloaded
+ versions of <tt>operator()</tt>?</li>
+<li> The definition of a strict weak ordering does not appear to give
+ any guidance on issues of overloading; it only discusses expressions,
+ and all of the values in these expressions are of the same type.
+ Some clarification would seem to be in order.</li>
+</ul>
+
+<p><i>Additional discussion from Copenhagen:</i></p>
+<ul>
+<li>It was generally agreed that there is a real defect here: if
+the predicate is merely required to be a Strict Weak Ordering, then
+it's possible to pass in a function object with an overloaded
+operator(), where the version that's actually called does something
+completely inappropriate. (Such as returning a random value.)</li>
+
+<li>An alternative formulation was presented in a paper distributed by
+David Abrahams at the meeting, "Binary Search with Heterogeneous
+Comparison", J16-01/0027 = WG21 N1313: Instead of viewing the
+predicate as a Strict Weak Ordering acting on a sorted sequence, view
+the predicate/value pair as something that partitions a sequence.
+This is almost equivalent to saying that we should view binary search
+as if we are given a unary predicate and a sequence, such that f(*p)
+is true for all p below a specific point and false for all p above it.
+The proposed resolution is based on that alternative formulation.</li>
+</ul>
+<p><b>Proposed resolution:</b></p>
+
+<p>Change 25.3 [lib.alg.sorting] paragraph 3 from:</p>
+
+<blockquote>
+ 3 For all algorithms that take Compare, there is a version that uses
+ operator< instead. That is, comp(*i, *j) != false defaults to *i <
+ *j != false. For the algorithms to work correctly, comp has to
+ induce a strict weak ordering on the values.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ 3 For all algorithms that take Compare, there is a version that uses
+ operator< instead. That is, comp(*i, *j) != false defaults to *i <
+ *j != false. For algorithms not described in lib.alg.binary.search
+ (25.3.3) to work correctly, comp has to induce a strict weak
+ ordering on the values.
+</blockquote>
+
+<p>Add the following paragraph after 25.3 [lib.alg.sorting] paragraph 5:</p>
+
+<blockquote>
+ -6- A sequence [start, finish) is partitioned with respect to an
+ expression f(e) if there exists a non-negative integer n such that
+ for all 0 <= i < distance(start, finish), f(*(begin+i)) is true if
+ and only if i < n.
+</blockquote>
+
+<p>Change 25.3.3 [lib.alg.binary.search] paragraph 1 from:</p>
+
+<blockquote>
+ -1- All of the algorithms in this section are versions of binary
+ search and assume that the sequence being searched is in order
+ according to the implied or explicit comparison function. They work
+ on non-random access iterators minimizing the number of
+ comparisons, which will be logarithmic for all types of
+ iterators. They are especially appropriate for random access
+ iterators, because these algorithms do a logarithmic number of
+ steps through the data structure. For non-random access iterators
+ they execute a linear number of steps.
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -1- All of the algorithms in this section are versions of binary
+ search and assume that the sequence being searched is partitioned
+ with respect to an expression formed by binding the search key to
+ an argument of the implied or explicit comparison function. They
+ work on non-random access iterators minimizing the number of
+ comparisons, which will be logarithmic for all types of
+ iterators. They are especially appropriate for random access
+ iterators, because these algorithms do a logarithmic number of
+ steps through the data structure. For non-random access iterators
+ they execute a linear number of steps.
+</blockquote>
+
+<p>Change 25.3.3.1 [lib.lower.bound] paragraph 1 from:</p>
+
+<blockquote>
+ -1- Requires: Type T is LessThanComparable
+ (lib.lessthancomparable).
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -1- Requires: The elements e of [first, last) are partitioned with
+ respect to the expression e < value or comp(e, value)
+</blockquote>
+
+
+<p>Remove 25.3.3.1 [lib.lower.bound] paragraph 2:</p>
+
+<blockquote>
+ -2- Effects: Finds the first position into which value can be
+ inserted without violating the ordering.
+</blockquote>
+
+<p>Change 25.3.3.2 [lib.upper.bound] paragraph 1 from:</p>
+
+<blockquote>
+ -1- Requires: Type T is LessThanComparable (lib.lessthancomparable).
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -1- Requires: The elements e of [first, last) are partitioned with
+ respect to the expression !(value < e) or !comp(value, e)
+</blockquote>
+
+<p>Remove 25.3.3.2 [lib.upper.bound] paragraph 2:</p>
+
+<blockquote>
+ -2- Effects: Finds the furthermost position into which value can be
+ inserted without violating the ordering.
+</blockquote>
+
+<p>Change 25.3.3.3 [lib.equal.range] paragraph 1 from:</p>
+
+<blockquote>
+ -1- Requires: Type T is LessThanComparable
+ (lib.lessthancomparable).
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -1- Requires: The elements e of [first, last) are partitioned with
+ respect to the expressions e < value and !(value < e) or
+ comp(e, value) and !comp(value, e).
+</blockquote>
+
+<p>
+Optionally add the following to the end of the proposed text above,
+which allows library implementors to make a small optimization at the
+cost of slightly complexifying the standard text. The idea is that we
+want to ensure that the partition point which defines the upper_bound
+is no earlier in the sequence than the partion point which defines the
+lower_bound, so that the implementor can do one of the searches over a
+subrange:
+</p>
+
+<blockquote>
+ Also, for all elements e of [first, last), e < value implies
+ !(value < e) or comp(e, value) implies !comp(value, e)
+</blockquote>
+
+<p>Note also that if we don't add the above, the result of
+equal_range() might be an invalid range.</p>
+
+
+<p>Change 25.3.3.3 [lib.equal.range] paragraph 2 from:</p>
+
+<blockquote>
+ -2- Effects: Finds the largest subrange [i, j) such that the value
+ can be inserted at any iterator k in it without violating the
+ ordering. k satisfies the corresponding conditions: !(*k < value)
+ && !(value < *k) or comp(*k, value) == false && comp(value, *k) ==
+ false.
+</blockquote>
+
+<p>to:</p>
+
+<pre>
+ -2- Returns:
+ make_pair(lower_bound(first, last, value),
+ upper_bound(first, last, value))
+ or
+ make_pair(lower_bound(first, last, value, comp),
+ upper_bound(first, last, value, comp))
+</pre>
+
+<p>
+Note that the original text did not say whether the first element of
+the return value was the beginning or end of the range, or something
+else altogether. The proposed text is both more precise and general
+enough to accomodate heterogeneous comparisons.
+</p>
+
+<p>Change 25.3.3.3 [lib.binary.search] paragraph 1 from:</p>
+
+<blockquote>
+ -1- Requires: Type T is LessThanComparable
+ (lib.lessthancomparable).
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ -1- Requires: The elements e of [first, last) are partitioned with
+ respect to the expressions e < value and !(value < e) or comp(e,
+ value) and !comp(value, e). Also, for all elements e of [first,
+ last), e < value implies !(value < e) or comp(e, value) implies
+ !comp(value, e)
+</blockquote>
+
+<p><i>[Dave Abrahams provided this wording]</i></p>
+
+<hr>
+<a name="271"><h3>271. basic_iostream missing typedefs</h3></a><p>
+<b>Section:</b> 27.6.1.5 <a href="lib-iostreams.html#lib.iostreamclass"> [lib.iostreamclass]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 02 Nov 2000</p>
+<p>
+Class template basic_iostream has no typedefs. The typedefs it
+inherits from its base classes can't be used, since (for example)
+basic_iostream<T>::traits_type is ambiguous.
+</p>
+<p><b>Proposed resolution:</b></p>
+
+<p>Add the following to basic_iostream's class synopsis in
+27.6.1.5 , immediately after <tt>public</tt>:</p>
+
+<pre>
+ // types:
+ typedef charT char_type;
+ typedef typename traits::int_type int_type;
+ typedef typename traits::pos_type pos_type;
+ typedef typename traits::off_type off_type;
+ typedef traits traits_type;
+</pre>
+<hr>
+<a name="272"><h3>272. Missing parentheses around subexpression</h3></a><p>
+<b>Section:</b> 27.4.4.3 <a href="lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 02 Nov 2000</p>
+<p>
+27.4.4.3, p4 says about the postcondition of the function: If
+rdbuf()!=0 then state == rdstate(); otherwise
+rdstate()==state|ios_base::badbit.
+</p>
+
+<p>
+The expression on the right-hand-side of the operator==() needs to be
+parenthesized in order for the whole expression to ever evaluate to
+anything but non-zero.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Add parentheses like so: rdstate()==(state|ios_base::badbit).
+</p>
+<hr>
+<a name="273"><h3>273. Missing ios_base qualification on members of a dependent class</h3></a><p>
+<b>Section:</b> 27 <a href="lib-iostreams.html#lib.input.output"> [lib.input.output]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 02 Nov 2000</p>
+<p>27.5.2.4.2, p4, and 27.8.1.6, p2, 27.8.1.7, p3, 27.8.1.9, p2,
+27.8.1.10, p3 refer to in and/or out w/o ios_base:: qualification.
+That's incorrect since the names are members of a dependent base
+class (14.6.2 [temp.dep]) and thus not visible.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Qualify the names with the name of the class of which they are
+members, i.e., ios_base.</p>
+<hr>
+<a name="274"><h3>274. a missing/impossible allocator requirement</h3></a><p>
+<b>Section:</b> 20.1.5 <a href="lib-utilities.html#lib.allocator.requirements"> [lib.allocator.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 02 Nov 2000</p>
+<p>
+I see that table 31 in 20.1.5, p3 allows T in std::allocator<T> to be of
+any type. But the synopsis in 20.4.1 calls for allocator<>::address() to
+be overloaded on reference and const_reference, which is ill-formed for
+all T = const U. In other words, this won't work:
+</p>
+
+<p>
+template class std::allocator<const int>;
+</p>
+
+<p>
+The obvious solution is to disallow specializations of allocators on
+const types. However, while containers' elements are required to be
+assignable (which rules out specializations on const T's), I think that
+allocators might perhaps be potentially useful for const values in other
+contexts. So if allocators are to allow const types a partial
+specialization of std::allocator<const T> would probably have to be
+provided.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the text in row 1, column 2 of table 32 in 20.1.5, p3 from</p>
+
+ <blockquote>
+ any type
+ </blockquote>
+
+<p>to</p>
+ <blockquote>
+ any non-const, non-volatile, non-reference type
+ </blockquote>
+<p><b>Rationale:</b></p>
+<p>
+Two resolutions were originally proposed: one that partially
+specialized std::allocator for const types, and one that said an
+allocator's value type may not be const. The LWG chose the second.
+The first wouldn't be appropriate, because allocators are intended for
+use by containers, and const value types don't work in containers.
+Encouraging the use of allocators with const value types would only
+lead to unsafe code.
+</p>
+<p>
+The original text for proposed resolution 2 was modified so that it
+also forbids volatile types and reference types.
+</p>
+<hr>
+<a name="275"><h3>275. Wrong type in num_get::get() overloads</h3></a><p>
+<b>Section:</b> 22.2.2.1.1 <a href="lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 02 Nov 2000</p>
+<p>
+In 22.2.2.1.1, we have a list of overloads for num_get<>::get().
+There are eight overloads, all of which are identical except for the
+last parameter. The overloads are:
+</p>
+<ul>
+<li> long& </li>
+<li> unsigned short& </li>
+<li> unsigned int& </li>
+<li> unsigned long& </li>
+<li> short& </li>
+<li> double& </li>
+<li> long double& </li>
+<li> void*& </li>
+</ul>
+
+<p>
+There is a similar list, in 22.2.2.1.2, of overloads for
+num_get<>::do_get(). In this list, the last parameter has
+the types:
+</p>
+<ul>
+<li> long& </li>
+<li> unsigned short& </li>
+<li> unsigned int& </li>
+<li> unsigned long& </li>
+<li> float& </li>
+<li> double& </li>
+<li> long double& </li>
+<li> void*& </li>
+</ul>
+
+<p>
+These two lists are not identical. They should be, since
+<tt>get</tt> is supposed to call <tt>do_get</tt> with exactly
+the arguments it was given.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.2.1.1 , change</p>
+<pre>
+ iter_type get(iter_type in, iter_type end, ios_base& str,
+ ios_base::iostate& err, short& val) const;
+</pre>
+<p>to</p>
+<pre>
+ iter_type get(iter_type in, iter_type end, ios_base& str,
+ ios_base::iostate& err, float& val) const;
+</pre>
+<hr>
+<a name="276"><h3>276. Assignable requirement for container value type overly strict</h3></a><p>
+<b>Section:</b> 23.1 <a href="lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Peter Dimov <b>Date:</b> 07 Nov 2000</p>
+<p>
+23.1/3 states that the objects stored in a container must be
+Assignable. 23.3.1 , paragraph 2,
+states that map satisfies all requirements for a container, while in
+the same time defining value_type as pair<const Key, T> - a type
+that is not Assignable.
+</p>
+
+<p>
+It should be noted that there exists a valid and non-contradictory
+interpretation of the current text. The wording in 23.1/3 avoids
+mentioning value_type, referring instead to "objects stored in a
+container." One might argue that map does not store objects of
+type map::value_type, but of map::mapped_type instead, and that the
+Assignable requirement applies to map::mapped_type, not
+map::value_type.
+</p>
+
+<p>
+However, this makes map a special case (other containers store objects of
+type value_type) and the Assignable requirement is needlessly restrictive in
+general.
+</p>
+
+<p>
+For example, the proposed resolution of active library issue
+<a href="lwg-defects.html#103">103</a> is to make set::iterator a constant iterator; this
+means that no set operations can exploit the fact that the stored
+objects are Assignable.
+</p>
+
+<p>
+This is related to, but slightly broader than, closed issue
+<a href="lwg-closed.html#140">140</a>.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>23.1/3: Strike the trailing part of the sentence:</p>
+ <blockquote>
+ , and the additional requirements of Assignable types from 23.1/3
+ </blockquote>
+<p>so that it reads:</p>
+ <blockquote>
+ -3- The type of objects stored in these components must meet the
+ requirements of CopyConstructible types (lib.copyconstructible).
+ </blockquote>
+
+<p>23.1/4: Modify to make clear that this requirement is not for all
+containers. Change to:</p>
+
+<blockquote>
+-4- Table 64 defines the Assignable requirement. Some containers
+require this property of the types to be stored in the container. T is
+the type used to instantiate the container. t is a value of T, and u is
+a value of (possibly const) T.
+</blockquote>
+
+<p>23.1, Table 65: in the first row, change "T is Assignable" to "T is
+CopyConstructible".</p>
+
+<p>23.2.1/2: Add sentence for Assignable requirement. Change to:</p>
+
+<blockquote>
+-2- A deque satisfies all of the requirements of a container and of a
+reversible container (given in tables in lib.container.requirements) and
+of a sequence, including the optional sequence requirements
+(lib.sequence.reqmts). In addition to the requirements on the stored
+object described in 23.1[lib.container.requirements], the stored object
+must also meet the requirements of Assignable. Descriptions are
+provided here only for operations on deque that are not described in one
+of these tables or for operations where there is additional semantic
+information.
+</blockquote>
+
+<p>23.2.2/2: Add Assignable requirement to specific methods of list.
+Change to:</p>
+
+<blockquote>
+<p>-2- A list satisfies all of the requirements of a container and of a
+reversible container (given in two tables in lib.container.requirements)
+and of a sequence, including most of the the optional sequence
+requirements (lib.sequence.reqmts). The exceptions are the operator[]
+and at member functions, which are not provided.
+
+[Footnote: These member functions are only provided by containers whose
+iterators are random access iterators. --- end foonote]
+</p>
+
+<p>list does not require the stored type T to be Assignable unless the
+following methods are instantiated:
+
+[Footnote: Implementors are permitted but not required to take advantage
+of T's Assignable properties for these methods. -- end foonote]
+</p>
+<pre>
+ list<T,Allocator>& operator=(const list<T,Allocator>& x );
+ template <class InputIterator>
+ void assign(InputIterator first, InputIterator last);
+ void assign(size_type n, const T& t);
+</pre>
+
+
+<p>Descriptions are provided here only for operations on list that are not
+described in one of these tables or for operations where there is
+additional semantic information.</p>
+</blockquote>
+
+<p>23.2.4/2: Add sentence for Assignable requirement. Change to:</p>
+
+<blockquote>
+-2- A vector satisfies all of the requirements of a container and of a
+reversible container (given in two tables in lib.container.requirements)
+and of a sequence, including most of the optional sequence requirements
+(lib.sequence.reqmts). The exceptions are the push_front and pop_front
+member functions, which are not provided. In addition to the
+requirements on the stored object described in
+23.1[lib.container.requirements], the stored object must also meet the
+requirements of Assignable. Descriptions are provided here only for
+operations on vector that are not described in one of these tables or
+for operations where there is additional semantic information.
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>list, set, multiset, map, multimap are able to store non-Assignables.
+However, there is some concern about <tt>list<T></tt>:
+although in general there's no reason for T to be Assignable, some
+implementations of the member functions <tt>operator=</tt> and
+<tt>assign</tt> do rely on that requirement. The LWG does not want
+to forbid such implementations.</p>
+
+<p>Note that the type stored in a standard container must still satisfy
+the requirements of the container's allocator; this rules out, for
+example, such types as "const int". See issue <a href="lwg-active.html#274">274</a>
+for more details.
+</p>
+
+<hr>
+<a name="278"><h3>278. What does iterator validity mean?</h3></a><p>
+<b>Section:</b> 23.2.2.4 <a href="lib-containers.html#lib.list.ops"> [lib.list.ops]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> P.J. Plauger <b>Date:</b> 27 Nov 2000</p>
+<p>
+Section 23.2.2.4 [lib.list.ops] states that
+</p>
+<pre>
+ void splice(iterator position, list<T, Allocator>& x);
+</pre>
+<p>
+<i>invalidates</i> all iterators and references to list <tt>x</tt>.
+</p>
+
+<p>
+But what does the C++ Standard mean by "invalidate"? You
+can still dereference the iterator to a spliced list element, but
+you'd better not use it to delimit a range within the original
+list. For the latter operation, it has definitely lost some of its
+validity.
+</p>
+
+<p>
+If we accept the proposed resolution to issue <a href="lwg-active.html#250">250</a>,
+then we'd better clarify that a "valid" iterator need no
+longer designate an element within the same container as it once did.
+We then have to clarify what we mean by invalidating a past-the-end
+iterator, as when a vector or string grows by reallocation. Clearly,
+such an iterator has a different kind of validity. Perhaps we should
+introduce separate terms for the two kinds of "validity."
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following text to the end of section 24.1 ,
+after paragraph 5:</p>
+<blockquote>
+<i>Invalidating</i> an iterator means modifying it such that
+it may have a singular value. [Footnote: This definition applies to
+pointers, since pointers are iterators. The effect of dereferencing
+an iterator that has been invalidated is undefined.]
+</blockquote>
+
+<p><i>[post-Copenhagen: Matt provided wording.]</i></p>
+
+<hr>
+<a name="280"><h3>280. Comparison of reverse_iterator to const reverse_iterator</h3></a><p>
+<b>Section:</b> 24.4.1 <a href="lib-iterators.html#lib.reverse.iterators"> [lib.reverse.iterators]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Steve Cleary <b>Date:</b> 27 Nov 2000</p>
+<p>
+This came from an email from Steve Cleary to Fergus in reference to
+issue <a href="lwg-active.html#179">179</a>. The library working group briefly discussed
+this in Toronto and believed it should be a separate issue. There was
+also some reservations about whether this was a worthwhile problem to
+fix.
+</p>
+
+<p>
+Steve said: "Fixing reverse_iterator. std::reverse_iterator can
+(and should) be changed to preserve these additional
+requirements." He also said in email that it can be done without
+breaking user's code: "If you take a look at my suggested
+solution, reverse_iterator doesn't have to take two parameters; there
+is no danger of breaking existing code, except someone taking the
+address of one of the reverse_iterator global operator functions, and
+I have to doubt if anyone has ever done that. . . <i>But</i>, just in
+case they have, you can leave the old global functions in as well --
+they won't interfere with the two-template-argument functions. With
+that, I don't see how <i>any</i> user code could break."
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+<b>Section:</b> 24.4.1.1
+add/change the following declarations:</p>
+<pre>
+ A) Add a templated assignment operator, after the same manner
+ as the templated copy constructor, i.e.:
+
+ template < class U >
+ reverse_iterator < Iterator >& operator=(const reverse_iterator< U >& u);
+
+ B) Make all global functions (except the operator+) have
+ two template parameters instead of one, that is, for
+ operator ==, !=, <, >, <=, >=, - replace:
+
+ template < class Iterator >
+ typename reverse_iterator< Iterator >::difference_type operator-(
+ const reverse_iterator< Iterator >& x,
+ const reverse_iterator< Iterator >& y);
+
+ with:
+
+ template < class Iterator1, class Iterator2 >
+ typename reverse_iterator < Iterator1 >::difference_type operator-(
+ const reverse_iterator < Iterator1 > & x,
+ const reverse_iterator < Iterator2 > & y);
+</pre>
+<p>
+Also make the addition/changes for these signatures in
+24.4.1.3 .
+</p>
+
+<p><i>[
+Copenhagen: The LWG is concerned that the proposed resolution
+introduces new overloads. Experience shows that introducing
+overloads is always risky, and that it would be inappropriate to
+make this change without implementation experience. It may be
+desirable to provide this feature in a different way.
+]</i></p>
+
+<hr>
+<a name="281"><h3>281. std::min() and max() requirements overly restrictive</h3></a><p>
+<b>Section:</b> 25.3.7 <a href="lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 02 Dec 2000</p>
+<p>The requirements in 25.3.7, p1 and 4 call for T to satisfy the
+requirements of <tt>LessThanComparable</tt> (20.1.2 )
+and <tt>CopyConstructible</tt> (20.1.3 ).
+Since the functions take and return their arguments and result by
+const reference, I believe the <tt>CopyConstructible</tt> requirement
+is unnecessary.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove the <tt>CopyConstructible</tt> requirement. Specifically, replace
+25.3.7, p1 with</p>
+<p>
+<b>-1- Requires:</b> Type T is <tt>LessThanComparable</tt>
+(20.1.2 ).
+</p>
+<p>and replace 25.3.7, p4 with</p>
+<p>
+<b>-4- Requires:</b> Type T is <tt>LessThanComparable</tt>
+(20.1.2 ).
+</p>
+<hr>
+<a name="282"><h3>282. What types does numpunct grouping refer to?</h3></a><p>
+<b>Section:</b> 22.2.2.2.2 <a href="lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 5 Dec 2000</p>
+<p>
+Paragraph 16 mistakenly singles out integral types for inserting
+thousands_sep() characters. This conflicts with the syntax for floating
+point numbers described under 22.2.3.1/2.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change paragraph 16 from:</p>
+
+<blockquote>
+For integral types, punct.thousands_sep() characters are inserted into
+the sequence as determined by the value returned by punct.do_grouping()
+using the method described in 22.2.3.1.2 .
+</blockquote>
+
+<p>To:</p>
+
+<blockquote>
+For arithmetic types, punct.thousands_sep() characters are inserted into
+the sequence as determined by the value returned by punct.do_grouping()
+using the method described in 22.2.3.1.2 .
+</blockquote>
+
+<p><i>[
+Copenhagen: Opinions were divided about whether this is actually an
+inconsistency, but at best it seems to have been unintentional. This
+is only an issue for floating-point output: The standard is
+unambiguous that implementations must parse thousands_sep characters
+when performing floating-point. The standard is also unambiguous that
+this requirement does not apply to the "C" locale.
+]</i></p>
+
+<p><i>[
+A survey of existing practice is needed; it is believed that some
+implementations do insert thousands_sep characters for floating-point
+output and others doing.
+]</i></p>
+
+<hr>
+<a name="283"><h3>283. std::replace() requirement incorrect/insufficient</h3></a><p>
+<b>Section:</b> 25.2.4 <a href="lib-algorithms.html#lib.alg.replace"> [lib.alg.replace]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 15 Dec 2000</p>
+<p>
+The requirements in 25.2.4 , p1 that <tt>T</tt> to be
+<tt>Assignable</tt> (23.1 ) is not necessary or
+sufficient for either of the algorithms. The algorithms require that
+<tt>std::iterator_traits<ForwardIterator>::value_type</tt> be
+<tt>Assignable</tt> and that both
+<tt>std::iterator_traits<ForwardIterator>::value_type</tt> and be
+<tt>EqualityComparable</tt> (20.1.1 ) with respect to
+one another.
+</p>
+
+<p>
+Note that a similar problem occurs in several other places in section
+25 as well (e.g., 25.1.6 , or 25.2.5 ) so
+what really needs to happen is for all those places to be identified
+and corrected. The proposed resolution below addresses only 25.2.4.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 25.2.4, p1 from</p>
+
+<blockquote>
+<b>-1- Requires:</b>Type <tt>T</tt> is <tt>Assignable</tt>
+(23.1 ) (and, for <tt>replace()</tt>,
+<tt>EqualityComparable</tt> (20.1.1 )).
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+<b>-1- Requires:</b>Type
+<tt>std::iterator_traits<ForwardIterator>::value_type</tt>
+is <tt>Assignable</tt> (23.1 ), the type <tt>T</tt> is
+convertible to<tt>std::iterator_traits<ForwardIterator>::value_type</tt>,
+(and, for <tt>replace()</tt>, types
+<tt>std::iterator_traits<ForwardIterator>::value_type</tt> and
+<tt>T</tt> are <tt>EqualityComparable</tt> (20.1.1 )
+with respect to one another).
+</blockquote>
+
+<p><i>[
+The LWG agrees with the general idea of the proposed resolution, but
+not with the specific wording. (There is no definition in the
+standard of what it means for one type to be EqualityComparable to
+another.) Jeremy will provide new wording, and will review clause 25
+for similar issues.
+]</i></p>
+
+<hr>
+<a name="284"><h3>284. unportable example in 20.3.7, p6</h3></a><p>
+<b>Section:</b> 20.3.7 <a href="lib-utilities.html#lib.function.pointer.adaptors"> [lib.function.pointer.adaptors]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 26 Dec 2000</p>
+<p>The example in 20.3.7 , p6 shows how to use the C
+library function <tt>strcmp()</tt> with the function pointer adapter
+<tt>ptr_fun()</tt>. But since it's unspecified whether the C library
+functions have <tt>extern "C"</tt> or <tt>extern
+"C++"</tt> linkage [17.4.2.2 ], and since
+function pointers with different the language linkage specifications
+(7.5 ) are incompatible, whether this example is
+well-formed is unspecified.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace the code snippet in the following text</p>
+<blockquote>
+ <p>
+<b>-6- </b>[<i>Example:</i>
+</p>
+ <pre>
+ replace_if(v.begin(), v.end(), not1(bind2nd(ptr_fun(strcmp), "C")), "C++");
+ </pre>
+</blockquote>
+
+
+<p>with</p>
+<blockquote>
+ <p>
+<b>-6- </b>[<i>Example:</i>
+</p>
+ <pre>
+ int compare(const char*, const char*);
+ replace_if(v.begin(), v.end(), not1(bind2nd(ptr_fun(compare), "abc")), "def");
+ </pre>
+</blockquote>
+
+<p><i>[Copenhagen: Minor change in the proposed resolution. Since this
+issue deals in part with C and C++ linkage, it was believed to be too
+confusing for the strings in the example to be "C" and "C++".
+]</i></p>
+<hr>
+<a name="285"><h3>285. minor editorial errors in fstream ctors</h3></a><p>
+<b>Section:</b> 27.8.1.6 <a href="lib-iostreams.html#lib.ifstream.cons"> [lib.ifstream.cons]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 31 Dec 2000</p>
+<p>27.8.1.6 , p2, 27.8.1.9 , p2, and
+27.8.1.12 , p2 say about the effects of each constructor:
+<a href="lib-iostreams.html#lib.ifstream.cons"> [lib.ifstream.cons]</a>
+</p>
+
+<p>... If that function returns a null pointer, calls
+<tt>setstate(failbit)</tt> (which may throw <tt>ios_base::failure</tt>).
+</p>
+
+<p>The parenthetical note doesn't apply since the ctors cannot throw an
+exception due to the requirement in 27.4.4.1 , p3
+that <tt>exceptions()</tt> be initialized to <tt>ios_base::goodbit</tt>.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Strike the parenthetical note from the Effects clause in each of the
+paragraphs mentioned above.
+</p>
+<hr>
+<a name="286"><h3>286. <cstdlib> requirements missing size_t typedef</h3></a><p>
+<b>Section:</b> 25.4 <a href="lib-algorithms.html#lib.alg.c.library"> [lib.alg.c.library]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 30 Dec 2000</p>
+<p>
+The <cstdlib> header file contains prototypes for bsearch and
+qsort (C++ Standard section 25.4 paragraphs 3 and 4) and other
+prototypes (C++ Standard section 21.4 paragraph 1 table 49) that
+require the typedef size_t. Yet size_t is not listed in the
+<cstdlib> synopsis table 78 in section 25.4.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Add the type size_t to Table 78 (section 25.4) and add
+the type size_t <cstdlib> to Table 97 (section C.2).
+</p>
+<p><b>Rationale:</b></p>
+<p>Since size_t is in <stdlib.h>, it must also be in <cstdlib>.</p>
+<hr>
+<a name="288"><h3>288. <cerrno> requirements missing macro EILSEQ</h3></a><p>
+<b>Section:</b> 19.3 <a href="lib-diagnostics.html#lib.errno"> [lib.errno]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 30 Dec 2000</p>
+<p>
+ISO/IEC 9899:1990/Amendment1:1994 Section 4.3 States: "The list
+of macros defined in <errno.h> is adjusted to include a new
+macro, EILSEQ"
+</p>
+
+<p>
+ISO/IEC 14882:1998(E) section 19.3 does not refer
+to the above amendment.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>
+Update Table 26 (section 19.3) "Header <cerrno> synopsis"
+and Table 95 (section C.2) "Standard Macros" to include EILSEQ.
+</p>
+<hr>
+<a name="290"><h3>290. Requirements to for_each and its function object</h3></a><p>
+<b>Section:</b> 25.1.1 <a href="lib-algorithms.html#lib.alg.foreach"> [lib.alg.foreach]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> 03 Jan 2001</p>
+<p>The specification of the for_each algorithm does not have a
+"Requires" section, which means that there are no
+restrictions imposed on the function object whatsoever. In essence it
+means that I can provide any function object with arbitrary side
+effects and I can still expect a predictable result. In particular I
+can expect that the function object is applied exactly last - first
+times, which is promised in the "Complexity" section.
+</p>
+
+<p>I don't see how any implementation can give such a guarantee
+without imposing requirements on the function object.
+</p>
+
+<p>Just as an example: consider a function object that removes
+elements from the input sequence. In that case, what does the
+complexity guarantee (applies f exactly last - first times) mean?
+</p>
+
+<p>One can argue that this is obviously a nonsensical application and
+a theoretical case, which unfortunately it isn't. I have seen
+programmers shooting themselves in the foot this way, and they did not
+understand that there are restrictions even if the description of the
+algorithm does not say so.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add a "Requires" section to section 25.1.1 similar to those
+proposed for transform and the numeric algorithms (see issue
+<a href="lwg-active.html#242">242</a>):
+</p>
+
+<blockquote>
+ -2- <b>Requires</b>: In the range [first, last], f shall not invalidate
+ iterators or subranges.
+</blockquote>
+
+<p><i>[Copenhagen: The LWG agrees that a function object passed to an
+algorithm should not invalidate iterators in the range that the
+algorithm is operating on. The LWG believes that this should be a
+blanket statement in Clause 25, not just a special requirement for
+<tt>for_each</tt>.
+]</i></p>
+
+<hr>
+<a name="291"><h3>291. Underspecification of set algorithms</h3></a><p>
+<b>Section:</b> 25.3.5 <a href="lib-algorithms.html#lib.alg.set.operations"> [lib.alg.set.operations]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 03 Jan 2001</p>
+<p>
+The standard library contains four algorithms that compute set
+operations on sorted ranges: <tt>set_union</tt>, <tt>set_intersection</tt>,
+<tt>set_difference</tt>, and <tt>set_symmetric_difference</tt>. Each
+of these algorithms takes two sorted ranges as inputs, and writes the
+output of the appropriate set operation to an output range. The elements
+in the output range are sorted.
+</p>
+
+<p>
+The ordinary mathematical definitions are generalized so that they
+apply to ranges containing multiple copies of a given element. Two
+elements are considered to be "the same" if, according to an
+ordering relation provided by the user, neither one is less than the
+other. So, for example, if one input range contains five copies of an
+element and another contains three, the output range of <tt>set_union</tt>
+will contain five copies, the output range of
+<tt>set_intersection</tt> will contain three, the output range of
+<tt>set_difference</tt> will contain two, and the output range of
+<tt>set_symmetric_difference</tt> will contain two.
+</p>
+
+<p>
+Because two elements can be "the same" for the purposes
+of these set algorithms, without being identical in other respects
+(consider, for example, strings under case-insensitive comparison),
+this raises a number of unanswered questions:
+</p>
+
+<ul>
+<li>If we're copying an element that's present in both of the
+input ranges, which one do we copy it from?</li>
+<li>If there are <i>n</i> copies of an element in the relevant
+input range, and the output range will contain fewer copies (say
+<i>m</i>) which ones do we choose? The first <i>m</i>, or the last
+<i>m</i>, or something else?</li>
+<li>Are these operations stable? That is, does a run of equivalent
+elements appear in the output range in the same order as as it
+appeared in the input range(s)?</li>
+</ul>
+
+<p>
+The standard should either answer these questions, or explicitly
+say that the answers are unspecified. I prefer the former option,
+since, as far as I know, all existing implementations behave the
+same way.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p><i>[The LWG agrees that the standard should answer these questions.
+Matt will provide wording.]</i></p>
+<hr>
+<a name="292"><h3>292. effects of a.copyfmt (a)</h3></a><p>
+<b>Section:</b> 27.4.4.2 <a href="lib-iostreams.html#lib.basic.ios.members"> [lib.basic.ios.members]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 05 Jan 2001</p>
+<p>The Effects clause of the member function <tt>copyfmt()</tt> in
+27.4.4.2, p15 doesn't consider the case where the left-hand side
+argument is identical to the argument on the right-hand side, that is
+<tt>(this == &rhs)</tt>. If the two arguments are identical there
+is no need to copy any of the data members or call any callbacks
+registered with <tt>register_callback()</tt>. Also, as Howard Hinnant
+points out in message c++std-lib-8149 it appears to be incorrect to
+allow the object to fire <tt>erase_event</tt> followed by
+<tt>copyfmt_event</tt> since the callback handling the latter event
+may inadvertently attempt to access memory freed by the former.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the Effects clause in 27.4.4.2, p15 from</p>
+
+<blockquote>
+<b>-15- Effects:</b>Assigns to the member objects of <tt>*this</tt>
+the corresponding member objects of <tt>rhs</tt>, except that...
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+<b>-15- Effects:</b>If <tt>(this == &rhs)</tt> does nothing. Otherwise
+assigns to the member objects of <tt>*this</tt> the corresponding member
+objects of <tt>rhs</tt>, except that...
+</blockquote>
+<hr>
+<a name="294"><h3>294. User defined macros and standard headers</h3></a><p>
+<b>Section:</b> 17.4.3.1.1 <a href="lib-intro.html#lib.macro.names"> [lib.macro.names]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> James Kanze <b>Date:</b> 11 Jan 2001</p>
+<p>Paragraph 2 of 17.4.3.1.1 reads: "A
+translation unit that includes a header shall not contain any macros
+that define names declared in that header." As I read this, it
+would mean that the following program is legal:</p>
+
+<pre>
+ #define npos 3.14
+ #include <sstream>
+</pre>
+
+<p>since npos is not defined in <sstream>. It is, however, defined
+in <string>, and it is hard to imagine an implementation in
+which <sstream> didn't include <string>.</p>
+
+<p>I think that this phrase was probably formulated before it was
+decided that a standard header may freely include other standard
+headers. The phrase would be perfectly appropriate for C, for
+example. In light of 17.4.4.1 paragraph 1, however,
+it isn't stringent enough.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In paragraph 2 of 17.4.3.1.1 , change "A
+translation unit that includes a header shall not contain any macros
+that define names declared in that header." to "A
+translation unit that includes a header shall not contain any macros
+that define names declared in any standard header."</p>
+
+<p><i>[Copenhagen: the general idea is clearly correct, but there is
+concern about making sure that the two paragraphs in 17.4.3.1.1 remain consistent. Nathan will provide new
+wording.]</i></p>
+
+<hr>
+<a name="295"><h3>295. Is abs defined in <cmath>?</h3></a><p>
+<b>Section:</b> 26.5 <a href="lib-numerics.html#lib.c.math"> [lib.c.math]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Jens Maurer <b>Date:</b> 12 Jan 2001</p>
+<p>
+Table 80 lists the contents of the <cmath> header. It does not
+list <tt>abs()</tt>. However, 26.5, paragraph 6, which lists added
+signatures present in <cmath>, does say that several overloads
+of <tt>abs()</tt> should be defined in <cmath>.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Add <tt>abs</tt> to Table 80. Also, remove the parenthetical list
+of functions "(abs(), div(), rand(), srand())" from 26.5 ,
+paragraph 1.
+</p>
+
+<p><i>[Copenhagen: Modified proposed resolution so that it also gets
+rid of that vestigial list of functions in paragraph 1.]</i></p>
+
+<hr>
+<a name="296"><h3>296. Missing descriptions and requirements of pair operators</h3></a><p>
+<b>Section:</b> 20.2.2 <a href="lib-utilities.html#lib.pairs"> [lib.pairs]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 14 Jan 2001</p>
+<p>The synopsis of the header <tt><utility></tt> in 20.2
+lists the complete set of equality and relational operators for <tt>pair</tt>
+but the section describing the template and the operators only describes
+<tt>operator==()</tt> and <tt>operator<()</tt>, and it fails to mention
+any requirements on the template arguments. The remaining operators are
+not mentioned at all.
+</p>
+<p><b>Proposed resolution:</b></p>
+
+<p>Add the following after 20.2.2 , paragraph 5:</p>
+
+<blockquote>
+ <blockquote>
+ <tt>template <class T1, class T2></tt>
+ <br><tt>bool operator!=(const pair<T1, T2>& x, const pair<T1,
+ T2>& y);</tt>
+ </blockquote>
+
+ <p>
+<b>Requires: </b>Types <tt>T1</tt> and <tt>T2</tt> are
+ <tt>EqualityComparable</tt> (20.1.1 ).</p>
+
+ <p>
+<b>Returns:</b> <tt>!(x == y)</tt>.</p>
+</blockquote>
+
+<p>Add the following after 20.2.2 , paragraph 6:</p>
+
+<blockquote>
+ <blockquote>
+ <tt>template <class T1, class T2></tt>
+ <br><tt>bool operator>(const pair<T1, T2>& x, const pair<T1, T2>& y);</tt>
+ </blockquote>
+
+ <p>
+<b>Requires: </b>Types <tt>T1</tt> and <tt>T2</tt> are
+ <tt>LessThanComparable</tt> (20.1.2 ).</p>
+
+ <p>
+<b>Returns:</b> <tt>y < x</tt>.</p>
+
+ <blockquote>
+ <tt>template <class T1, class T2></tt>
+ <br><tt>bool operator<=(const pair<T1, T2>& x, const pair<T1, T2>& y);</tt>
+ </blockquote>
+
+ <p>
+<b>Requires: </b>Types <tt>T1</tt> and <tt>T2</tt> are
+ <tt>LessThanComparable</tt> (20.1.2 ).</p>
+
+ <p>
+<b>Returns: </b><tt>!(y < x)</tt>.</p>
+
+ <blockquote>
+ <tt>template <class T1, class T2></tt>
+ <br><tt>bool operator>=(const pair<T1, T2>& x, const pair<T1, T2>& y);</tt>
+ </blockquote>
+
+ <p>
+<b>Requires: </b>Types <tt>T1</tt> and <tt>T2</tt> are
+ <tt>LessThanComparable</tt> (20.1.2 ).</p>
+
+ <p>
+<b>Returns:</b> <tt>!(x < y)</tt>.</p>
+</blockquote>
+
+<p><i>[post-Copenhagen: modified proposed resolution so that it does
+not create a new section 20.2.2.1. That would violate ISO rules: we
+cannot have 20.2.2.1 unless we also have 20.2.2.2.]</i></p>
+
+<hr>
+<a name="297"><h3>297. const_mem_fun_t<>::argument_type should be const T*</h3></a><p>
+<b>Section:</b> 20.3.8 <a href="lib-utilities.html#lib.member.pointer.adaptors"> [lib.member.pointer.adaptors]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 6 Jan 2001</p>
+<p>The class templates <tt>const_mem_fun_t</tt> in 20.3.8, p8 and
+<tt>const_mem_fun1_t</tt>
+in 20.3.8, p9 derive from <tt>unary_function<T*, S></tt>, and
+<tt>binary_function<T*,
+A, S></tt>, respectively. Consequently, their <tt>argument_type</tt>, and
+<tt>first_argument_type</tt>
+members, respectively, are both defined to be <tt>T*</tt> (non-const).
+However, their function call member operator takes a <tt>const T*</tt>
+argument. It is my opinion that <tt>argument_type</tt> should be <tt>const
+T*</tt> instead, so that one can easily refer to it in generic code. The
+example below derived from existing code fails to compile due to the
+discrepancy:
+</p>
+
+<p>
+<tt>template <class T></tt>
+<br><tt>void foo (typename T::argument_type arg) // #1</tt>
+<br><tt>{</tt>
+<br><tt> typename T::result_type (T::*pf) (typename
+T::argument_type)
+const = // #2</tt>
+<br><tt> &T::operator();</tt>
+<br><tt>}</tt>
+</p>
+
+<p><tt>struct X { /* ... */ };</tt></p>
+
+<p>
+<tt>int main ()</tt>
+<br><tt>{</tt>
+<br><tt> const X x;</tt>
+<br><tt> foo<std::const_mem_fun_t<void, X>
+>(&x);
+// #3</tt>
+<br><tt>}</tt>
+</p>
+
+<p>#1 <tt>foo()</tt> takes a plain unqualified <tt>X*</tt> as an argument
+<br>#2 the type of the pointer is incompatible with the type of the member
+function
+<br>#3 the address of a constant being passed to a function taking a non-const
+<tt>X*</tt>
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace the top portion of the definition of the class template
+const_mem_fun_t in 20.3.8, p8
+</p>
+<p>
+<tt>template <class S, class T> class const_mem_fun_t</tt>
+<br><tt> : public
+unary_function<T*, S> {</tt>
+</p>
+<p>with</p>
+<p>
+<tt>template <class S, class T> class const_mem_fun_t</tt>
+<br><tt> : public
+unary_function<<b>const</b> T*, S> {</tt>
+</p>
+<p>Also replace the top portion of the definition of the class template
+const_mem_fun1_t in 20.3.8, p9</p>
+<p>
+<tt>template <class S, class T, class A> class const_mem_fun1_t</tt>
+<br><tt> : public
+binary_function<T*, A, S> {</tt>
+</p>
+<p>with</p>
+<p>
+<tt>template <class S, class T, class A> class const_mem_fun1_t</tt>
+<br><tt> : public
+binary_function<<b>const</b> T*, A, S> {</tt>
+</p>
+<p><b>Rationale:</b></p>
+<p>This is simply a contradiction: the <tt>argument_type</tt> typedef,
+and the argument type itself, are not the same.</p>
+<hr>
+<a name="298"><h3>298. ::operator delete[] requirement incorrect/insufficient</h3></a><p>
+<b>Section:</b> 18.4.1.2 <a href="lib-support.html#lib.new.delete.array"> [lib.new.delete.array]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> John A. Pedretti <b>Date:</b> 10 Jan 2001</p>
+<p>
+The default behavior of <tt>operator delete[]</tt> described in 18.4.1.2, p12 -
+namely that for non-null value of <i>ptr</i>, the operator reclaims storage
+allocated by the earlier call to the default <tt>operator new[]</tt> - is not
+correct in all cases. Since the specified <tt>operator new[]</tt> default
+behavior is to call <tt>operator new</tt> (18.4.1.2, p4, p8), which can be
+replaced, along with <tt>operator delete</tt>, by the user, to implement their
+own memory management, the specified default behavior of<tt> operator
+delete[]</tt> must be to call <tt>operator delete</tt>.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 18.4.1.2, p12 from</p>
+<blockquote>
+<b>-12-</b> <b>Default behavior:</b>
+<ul>
+<li>
+For a null value of <i><tt>ptr</tt></i> , does nothing.
+</li>
+<li>
+Any other value of <i><tt>ptr</tt></i> shall be a value returned
+earlier by a call to the default <tt>operator new[](std::size_t)</tt>.
+[Footnote: The value must not have been invalidated by an intervening
+call to <tt>operator delete[](void*)</tt> (17.4.3.7 ).
+--- end footnote]
+For such a non-null value of <i><tt>ptr</tt></i> , reclaims storage
+allocated by the earlier call to the default <tt>operator new[]</tt>.
+</li>
+</ul>
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+<b>-12-</b> <b>Default behavior: </b>Calls <tt>operator
+delete(</tt><i>ptr</i>)
+or <tt>operator delete(<i>ptr</i>, std::nothrow)</tt> respectively.
+</blockquote>
+<p>and expunge paragraph 13.</p>
+<hr>
+<a name="299"><h3>299. Incorrect return types for iterator dereference</h3></a><p>
+<b>Section:</b> 24.1.4 <a href="lib-iterators.html#lib.bidirectional.iterators"> [lib.bidirectional.iterators]</a>, 24.1.5 <a href="lib-iterators.html#lib.random.access.iterators"> [lib.random.access.iterators]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> John Potter <b>Date:</b> 22 Jan 2001</p>
+<p>
+In section 24.1.4 ,
+Table 75 gives the return type of *r-- as convertible to T. This is
+not consistent with Table 74 which gives the return type of *r++ as
+T&. *r++ = t is valid while *r-- = t is invalid.
+</p>
+
+<p>
+In section 24.1.5 ,
+Table 76 gives the return type of a[n] as convertible to T. This is
+not consistent with the semantics of *(a + n) which returns T& by
+Table 74. *(a + n) = t is valid while a[n] = t is invalid.
+</p>
+
+<p>
+Discussion from the Copenhagen meeting: the first part is
+uncontroversial. The second part, operator[] for Random Access
+Iterators, requires more thought. There are reasonable arguments on
+both sides. Return by value from operator[] enables some potentially
+useful iterators, e.g. a random access "iota iterator" (a.k.a
+"counting iterator" or "int iterator"). There isn't any obvious way
+to do this with return-by-reference, since the reference would be to a
+temporary. On the other hand, <tt>reverse_iterator</tt> takes an
+arbitrary Random Access Iterator as template argument, and its
+operator[] returns by reference. If we decided that the return type
+in Table 76 was correct, we would have to change
+<tt>reverse_iterator</tt>. This change would probably affect user
+code.
+</p>
+
+<p>
+History: the contradiction between <tt>reverse_iterator</tt> and the
+Random Access Iterator requirements has been present from an early
+stage. In both the STL proposal adopted by the committee
+(N0527==94-0140) and the STL technical report (HPL-95-11 (R.1), by
+Stepanov and Lee), the Random Access Iterator requirements say that
+operator[]'s return value is "convertible to T". In N0527
+reverse_iterator's operator[] returns by value, but in HPL-95-11
+(R.1), and in the STL implementation that HP released to the public,
+reverse_iterator's operator[] returns by reference. In 1995, the
+standard was amended to reflect the contents of HPL-95-11 (R.1). The
+original intent for operator[] is unclear.
+</p>
+
+<p>
+In the long term it may be desirable to add more fine-grained
+iterator requirements, so that access method and traversal strategy
+can be decoupled. (See "Improved Iterator Categories and
+Requirements", N1297 = 01-0011, by Jeremy Siek.) Any decisions
+about issue 299 should keep this possibility in mind.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>In section 24.1.4 , change the return type in table
+75 from "convertible to T" to T&.</p>
+
+<p>In section 24.1.5 , change the return type in table
+76 from "convertible to T" to T&.</p>
+
+<hr>
+<a name="300"><h3>300. list::merge() specification incomplete</h3></a><p>
+<b>Section:</b> 23.2.2.4 <a href="lib-containers.html#lib.list.ops"> [lib.list.ops]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> John Pedretti <b>Date:</b> 23 Jan 2001</p>
+<p>
+The "Effects" clause for list::merge() (23.2.2.4, p23)
+appears to be incomplete: it doesn't cover the case where the argument
+list is identical to *this (i.e., this == &x). The requirement in the
+note in p24 (below) is that x be empty after the merge which is surely
+unintended in this case.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Change 23.2.2.4, p23 to:
+</p>
+<blockquote>
+<b>Effects</b>: If &x == this, does nothing; otherwise, merges the
+argument list into the list.
+</blockquote>
+
+<p><i>[Copenhagen: The proposed resolution does not fix all of the
+problems in 23.2.2.4 , p22-25. Three different
+paragraphs (23, 24, 25) describe the effects of <tt>merge</tt>.
+Changing p23, without changing the other two, appears to introduce
+contradictions. Additionally, "merges the argument list into the
+list" is excessively vague.]</i></p>
+
+<hr>
+<a name="301"><h3>301. basic_string template ctor effects clause omits allocator argument</h3></a><p>
+<b>Section:</b> 21.3.1 <a href="lib-strings.html#lib.string.cons"> [lib.string.cons]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 27 Jan 2001</p>
+<p>
+The effects clause for the basic_string template ctor in 21.3.1, p15
+leaves out the third argument of type Allocator. I believe this to be
+a mistake.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace</p>
+
+<blockquote>
+ <p>
+<b>-15- Effects:</b> If <i><tt>InputIterator</tt></i> is an integral
+ type, equivalent to</p>
+
+ <blockquote><tt>basic_string(static_cast<size_type>(begin),
+ static_cast<value_type>(end))</tt></blockquote>
+</blockquote>
+
+<p>with</p>
+
+<blockquote>
+ <p>
+<b>-15- Effects:</b> If <i><tt>InputIterator</tt></i> is an integral
+ type, equivalent to</p>
+
+ <blockquote><tt>basic_string(static_cast<size_type>(begin),
+ static_cast<value_type>(end), <b>a</b>)</tt></blockquote>
+</blockquote>
+<hr>
+<a name="303"><h3>303. Bitset input operator underspecified</h3></a><p>
+<b>Section:</b> 23.3.5.3 <a href="lib-containers.html#lib.bitset.operators"> [lib.bitset.operators]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 5 Feb 2001</p>
+<p>
+In 23.3.5.3, we are told that <tt>bitset</tt>'s input operator
+"Extracts up to <i>N</i> (single-byte) characters from
+<i>is</i>.", where <i>is</i> is a stream of type
+<tt>basic_istream<charT, traits></tt>.
+</p>
+
+<p>
+The standard does not say what it means to extract single byte
+characters from a stream whose character type, <tt>charT</tt>, is in
+general not a single-byte character type. Existing implementations
+differ.
+</p>
+
+<p>
+A reasonable solution will probably involve <tt>widen()</tt> and/or
+<tt>narrow()</tt>, since they are the supplied mechanism for a single
+character between <tt>char</tt> and arbitrary <tt>charT</tt>.
+</p>
+
+<p>Narrowing the input characters is not the same as widening the
+literals <tt>'0'</tt> and <tt>'1'</tt>, because there may be some
+locales in which more than one wide character maps to the narrow
+character <tt>'0'</tt>. Narrowing means that alternate
+representations may be used for bitset input, widening means that
+they may not be.</p>
+
+<p>Note that for numeric input, <tt>num_get<></tt>
+(22.2.2.1.2/8) compares input characters to widened version of narrow
+character literals.</p>
+
+<p>From Pete Becker, in c++std-lib-8224:</p>
+<blockquote>
+<p>
+Different writing systems can have different representations for the
+digits that represent 0 and 1. For example, in the Unicode representation
+of the Devanagari script (used in many of the Indic languages) the digit 0
+is 0x0966, and the digit 1 is 0x0967. Calling narrow would translate those
+into '0' and '1'. But Unicode also provides the ASCII values 0x0030 and
+0x0031 for for the Latin representations of '0' and '1', as well as code
+points for the same numeric values in several other scripts (Tamil has no
+character for 0, but does have the digits 1-9), and any of these values
+would also be narrowed to '0' and '1'.
+</p>
+
+<p>...</p>
+
+<p>
+It's fairly common to intermix both native and Latin
+representations of numbers in a document. So I think the rule has to be
+that if a wide character represents a digit whose value is 0 then the bit
+should be cleared; if it represents a digit whose value is 1 then the bit
+should be set; otherwise throw an exception. So in a Devanagari locale,
+both 0x0966 and 0x0030 would clear the bit, and both 0x0967 and 0x0031
+would set it. Widen can't do that. It would pick one of those two values,
+and exclude the other one.
+</p>
+
+</blockquote>
+
+<p>From Jens Maurer, in c++std-lib-8233:</p>
+
+<blockquote>
+<p>
+Whatever we decide, I would find it most surprising if
+bitset conversion worked differently from int conversion
+with regard to alternate local representations of
+numbers.
+</p>
+
+<p>Thus, I think the options are:</p>
+<ul>
+ <li> Have a new defect issue for 22.2.2.1.2/8 so that it will
+require the use of narrow().</li>
+
+ <li> Have a defect issue for bitset() which describes clearly
+that widen() is to be used.</li>
+</ul>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+
+ <p>Replace the first two sentences of paragraph 5 with:</p>
+
+ <blockquote>
+ Extracts up to <i>N</i> characters from <i>is</i>. Stores these
+ characters in a temporary object <i>str</i> of type
+ <tt>basic_string<charT, traits></tt>, then evaluates the
+ expression <tt><i>x</i> = bitset<N>(<i>str</i>)</tt>.
+ </blockquote>
+
+ <p>Replace the third bullet item in paragraph 5 with:</p>
+ <ul><li>
+ the next input character is neither <tt><i>is</i>.widen(0)</tt>
+ nor <tt><i>is</i>.widen(1)</tt> (in which case the input character
+ is not extracted).
+ </li></ul>
+
+<p><b>Rationale:</b></p>
+<p>Input for <tt>bitset</tt> should work the same way as numeric
+input. Using <tt>widen</tt> does mean that alternative digit
+representations will not be recognized, but this was a known
+consequence of the design choice.</p>
+<hr>
+<a name="304"><h3>304. Must <tt>*a</tt> return an lvalue when <tt>a</tt> is an input iterator?</h3></a><p>
+<b>Section:</b> 24.1 <a href="lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 5 Feb 2001</p>
+<p>
+We all "know" that input iterators are allowed to produce
+values when dereferenced of which there is no other in-memory copy.
+</p>
+
+<p>
+But: Table 72, with a careful reading, seems to imply that this can only be
+the case if the value_type has no members (e.g. is a built-in type).
+</p>
+
+<p>The problem occurs in the following entry:</p>
+
+<pre>
+ a->m pre: (*a).m is well-defined
+ Equivalent to (*a).m
+</pre>
+
+<p>
+<tt>*a.m</tt> can be well-defined if <tt>*a</tt> is not a reference
+type, but since <tt>operator->()</tt> must return a pointer for
+<tt>a->m</tt> to be well-formed, it needs something to return a
+pointer <i>to</i>. This seems to indicate that <tt>*a</tt> must be
+buffered somewhere to make a legal input iterator.
+</p>
+
+<p>I don't think this was intentional.</p>
+<p><b>Proposed resolution:</b></p>
+<p><i>[Copenhagen: the two obvious possibilities are to keep the
+<tt>operator-></tt> requirement for Input Iterators, and put
+in a non-normative note describing how it can be implemented with
+proxies, or else moving the <tt>operator-></tt> requirement
+from Input Iterator to Forward Iterator. If we do the former
+we'll also have to change <tt>istreambuf_iterator</tt>, because
+it has no <tt>operator-></tt>. A straw poll showed roughly equal
+support for the two options.]</i></p>
+<hr>
+<a name="305"><h3>305. Default behavior of codecvt<wchar_t, char, mbstate_t>::length()</h3></a><p>
+<b>Section:</b> 22.2.1.5.2 <a href="lib-locales.html#lib.locale.codecvt.virtuals"> [lib.locale.codecvt.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 24 Jan 2001</p>
+<p>22.2.1.5/3 introduces codecvt in part with:</p>
+
+<blockquote>
+ codecvt<wchar_t,char,mbstate_t> converts between the native
+ character sets for tiny and wide characters. Instantiations on
+ mbstate_t perform conversion between encodings known to the library
+ implementor.
+</blockquote>
+
+<p>But 22.2.1.5.2/10 describes do_length in part with:</p>
+
+<blockquote>
+ ... codecvt<wchar_t, char, mbstate_t> ... return(s) the lesser of max and
+ (from_end-from).
+</blockquote>
+
+<p>
+The semantics of do_in and do_length are linked. What one does must
+be consistent with what the other does. 22.2.1.5/3 leads me to
+believe that the vendor is allowed to choose the algorithm that
+codecvt<wchar_t,char,mbstate_t>::do_in performs so that it makes
+his customers happy on a given platform. But 22.2.1.5.2/10 explicitly
+says what codecvt<wchar_t,char,mbstate_t>::do_length must
+return. And thus indirectly specifies the algorithm that
+codecvt<wchar_t,char,mbstate_t>::do_in must perform. I believe
+that this is not what was intended and is a defect.
+</p>
+
+<p>Discussion from the -lib reflector:
+
+<br>This proposal would have the effect of making the semantics of
+all of the virtual functions in <tt>codecvt<wchar_t, char,
+mbstate_t></tt> implementation specified. Is that what we want, or
+do we want to mandate specific behavior for the base class virtuals
+and leave the implementation specified behavior for the codecvt_byname
+derived class? The tradeoff is that former allows implementors to
+write a base class that actually does something useful, while the
+latter gives users a way to get known and specified---albeit
+useless---behavior, and is consistent with the way the standard
+handles other facets. It is not clear what the original intention
+was.</p>
+
+<p>
+Nathan has suggest a compromise: a character that is a widened version
+of the characters in the basic execution character set must be
+converted to a one-byte sequence, but there is no such requirement
+for characters that are not part of the basic execution character set.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 22.2.1.5.2/10 from:</p>
+
+<blockquote>
+-10- Returns: (from_next-from) where from_next is the largest value in
+the range [from,from_end] such that the sequence of values in the
+range [from,from_next) represents max or fewer valid complete
+characters of type internT. The instantiations required in Table 51
+(21.1.1.1.1), namely codecvt<wchar_t, char, mbstate_t> and
+codecvt<char, char, mbstate_t>, return the lesser of max and
+(from_end-from).
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+-10- Returns: (from_next-from) where from_next is the largest value in
+the range [from,from_end] such that the sequence of values in the range
+[from,from_next) represents max or fewer valid complete characters of
+type internT. The instantiation codecvt<char, char, mbstate_t> returns
+the lesser of max and (from_end-from).
+</blockquote>
+
+<p><i>[Copenhagen: straw poll was 3-1 in favor, with many abstentions.
+Nathan would like to see more guarantees than are in the proposed
+resolution. He will discuss this issue with the other people who
+care about it.]</i></p>
+
+<hr>
+<a name="306"><h3>306. offsetof macro and non-POD types</h3></a><p>
+<b>Section:</b> 18.1 <a href="lib-support.html#lib.support.types"> [lib.support.types]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 21 Feb 2001</p>
+<p>Spliced together from reflector messages c++std-lib-8294 and -8295:</p>
+
+<p>18.1, paragraph 5, reads: "The macro <tt>offsetof</tt>
+accepts a restricted set of <i>type</i> arguments in this
+International Standard. <i>type</i> shall be a POD structure or a POD
+union (clause 9). The result of applying the offsetof macro to a field
+that is a static data member or a function member is
+undefined."</p>
+
+<p>For the POD requirement, it doesn't say "no diagnostic
+required" or "undefined behavior". I read 1.4 , paragraph 1, to mean that a diagnostic is required.
+It's not clear whether this requirement was intended. While it's
+possible to provide such a diagnostic, the extra complication doesn't
+seem to add any value.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 18.1, paragraph 5, to "If <i>type</i> is not a POD
+structure or a POD union the results are undefined."</p>
+
+<p><i>[Copenhagen: straw poll was 7-4 in favor. It was generally
+agreed that requiring a diagnostic was inadvertent, but some LWG
+members thought that diagnostics should be required whenever
+possible.]</i></p>
+
+<hr>
+<a name="307"><h3>307. Lack of reference typedefs in container adaptors</h3></a><p>
+<b>Section:</b> 23.2.3 <a href="lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 13 Mar 2001</p>
+
+<p>From reflector message c++std-lib-8330. See also lib-8317.</p>
+
+<p>
+The standard is currently inconsistent in 23.2.3.2
+paragraph 1 and 23.2.3.3 paragraph 1.
+23.2.3.3/1, for example, says:
+</p>
+
+<blockquote>
+-1- Any sequence supporting operations back(), push_back() and pop_back()
+can be used to instantiate stack. In particular, vector (lib.vector), list
+(lib.list) and deque (lib.deque) can be used.
+</blockquote>
+
+<p>But this is false: vector<bool> can not be used, because the
+container adaptors return a T& rather than using the underlying
+container's reference type.</p>
+
+<p>This is a contradiction that can be fixed by:</p>
+
+<ol>
+<li>Modifying these paragraphs to say that vector<bool>
+ is an exception.</li>
+<li>Removing the vector<bool> specialization.</li>
+<li>Changing the return types of stack and priority_queue to use
+ reference typedef's.</li>
+</ol>
+
+<p>
+I propose 3. This does not preclude option 2 if we choose to do it
+later (see issue <a href="lwg-active.html#96">96</a>); the issues are independent. Option
+3 offers a small step towards support for proxied containers. This
+small step fixes a current contradiction, is easy for vendors to
+implement, is already implemented in at least one popular lib, and
+does not break any code.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Summary: Add reference and const_reference typedefs to queue,
+priority_queue and stack. Change return types of "value_type&" to
+"reference". Change return types of "const value_type&" to
+"const_reference". Details:</p>
+
+<p>Change 23.2.3.1/1 from:</p>
+
+<pre>
+ namespace std {
+ template <class T, class Container = deque<T> >
+ class queue {
+ public:
+ typedef typename Container::value_type value_type;
+ typedef typename Container::size_type size_type;
+ typedef Container container_type;
+ protected:
+ Container c;
+
+ public:
+ explicit queue(const Container& = Container());
+
+ bool empty() const { return c.empty(); }
+ size_type size() const { return c.size(); }
+ value_type& front() { return c.front(); }
+ const value_type& front() const { return c.front(); }
+ value_type& back() { return c.back(); }
+ const value_type& back() const { return c.back(); }
+ void push(const value_type& x) { c.push_back(x); }
+ void pop() { c.pop_front(); }
+ };
+</pre>
+
+<p>to:</p>
+
+<pre>
+ namespace std {
+ template <class T, class Container = deque<T> >
+ class queue {
+ public:
+ typedef typename Container::value_type value_type;
+ typedef typename Container::reference reference;
+ typedef typename Container::const_reference const_reference;
+ typedef typename Container::value_type value_type;
+ typedef typename Container::size_type size_type;
+ typedef Container container_type;
+ protected:
+ Container c;
+
+ public:
+ explicit queue(const Container& = Container());
+
+ bool empty() const { return c.empty(); }
+ size_type size() const { return c.size(); }
+ reference front() { return c.front(); }
+ const_reference front() const { return c.front(); }
+ reference back() { return c.back(); }
+ const_reference back() const { return c.back(); }
+ void push(const value_type& x) { c.push_back(x); }
+ void pop() { c.pop_front(); }
+ };
+</pre>
+
+<p>Change 23.2.3.2/1 from:</p>
+
+<pre>
+ namespace std {
+ template <class T, class Container = vector<T>,
+ class Compare = less<typename Container::value_type> >
+ class priority_queue {
+ public:
+ typedef typename Container::value_type value_type;
+ typedef typename Container::size_type size_type;
+ typedef Container container_type;
+ protected:
+ Container c;
+ Compare comp;
+
+ public:
+ explicit priority_queue(const Compare& x = Compare(),
+ const Container& = Container());
+ template <class InputIterator>
+ priority_queue(InputIterator first, InputIterator last,
+ const Compare& x = Compare(),
+ const Container& = Container());
+
+ bool empty() const { return c.empty(); }
+ size_type size() const { return c.size(); }
+ const value_type& top() const { return c.front(); }
+ void push(const value_type& x);
+ void pop();
+ };
+ // no equality is provided
+ }
+</pre>
+
+<p>to:</p>
+
+<pre>
+ namespace std {
+ template <class T, class Container = vector<T>,
+ class Compare = less<typename Container::value_type> >
+ class priority_queue {
+ public:
+ typedef typename Container::value_type value_type;
+ typedef typename Container::reference reference;
+ typedef typename Container::const_reference const_reference;
+ typedef typename Container::size_type size_type;
+ typedef Container container_type;
+ protected:
+ Container c;
+ Compare comp;
+
+ public:
+ explicit priority_queue(const Compare& x = Compare(),
+ const Container& = Container());
+ template <class InputIterator>
+ priority_queue(InputIterator first, InputIterator last,
+ const Compare& x = Compare(),
+ const Container& = Container());
+
+ bool empty() const { return c.empty(); }
+ size_type size() const { return c.size(); }
+ const_reference top() const { return c.front(); }
+ void push(const value_type& x);
+ void pop();
+ };
+ // no equality is provided
+ }
+</pre>
+
+<p>And change 23.2.3.3/1 from:</p>
+
+<pre>
+ namespace std {
+ template <class T, class Container = deque<T> >
+ class stack {
+ public:
+ typedef typename Container::value_type value_type;
+ typedef typename Container::size_type size_type;
+ typedef Container container_type;
+ protected:
+ Container c;
+
+ public:
+ explicit stack(const Container& = Container());
+
+ bool empty() const { return c.empty(); }
+ size_type size() const { return c.size(); }
+ value_type& top() { return c.back(); }
+ const value_type& top() const { return c.back(); }
+ void push(const value_type& x) { c.push_back(x); }
+ void pop() { c.pop_back(); }
+ };
+
+ template <class T, class Container>
+ bool operator==(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator< (const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator!=(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator> (const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator>=(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator<=(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ }
+</pre>
+
+<p>to:</p>
+
+<pre>
+ namespace std {
+ template <class T, class Container = deque<T> >
+ class stack {
+ public:
+ typedef typename Container::value_type value_type;
+ typedef typename Container::reference reference;
+ typedef typename Container::const_reference const_reference;
+ typedef typename Container::size_type size_type;
+ typedef Container container_type;
+ protected:
+ Container c;
+
+ public:
+ explicit stack(const Container& = Container());
+
+ bool empty() const { return c.empty(); }
+ size_type size() const { return c.size(); }
+ reference top() { return c.back(); }
+ const_reference top() const { return c.back(); }
+ void push(const value_type& x) { c.push_back(x); }
+ void pop() { c.pop_back(); }
+ };
+
+ template <class T, class Container>
+ bool operator==(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator< (const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator!=(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator> (const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator>=(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ template <class T, class Container>
+ bool operator<=(const stack<T, Container>& x,
+ const stack<T, Container>& y);
+ }
+</pre>
+
+<p><i>[Copenhagen: This change was discussed before the IS was released
+and it was deliberately not adopted. Nevertheless, the LWG believes
+(straw poll: 10-2) that it is a genuine defect.]</i></p>
+
+<hr>
+<a name="308"><h3>308. Table 82 mentions unrelated headers</h3></a><p>
+<b>Section:</b> 27 <a href="lib-iostreams.html#lib.input.output"> [lib.input.output]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 15 Mar 2001</p>
+<p>
+Table 82 in section 27 mentions the header <cstdlib> for String
+streams (27.7 ) and the headers <cstdio> and
+<cwchar> for File streams (27.8 ). It's not clear
+why these headers are mentioned in this context since they do not
+define any of the library entities described by the
+subclauses. According to 17.4.1.1 , only such headers
+are to be listed in the summary.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove <cstdlib> and <cwchar> from
+Table 82.</p>
+
+<p><i>[Copenhagen: changed the proposed resolution slightly. The
+original proposed resolution also said to remove <cstdio> from
+Table 82. However, <cstdio> is mentioned several times within
+section 27.8 , including 27.8.2 .]</i></p>
+
+<hr>
+<a name="309"><h3>309. Does sentry catch exceptions?</h3></a><p>
+<b>Section:</b> 27.6 <a href="lib-iostreams.html#lib.iostream.format"> [lib.iostream.format]</a> <b>Status:</b> <a href="lwg-active.html#Open">Open</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 19 Mar 2001</p>
+<p>
+The descriptions of the constructors of basic_istream<>::sentry
+(27.6.1.1.2 ) and basic_ostream<>::sentry
+(27.6.2.3 ) do not explain what the functions do in
+case an exception is thrown while they execute. Some current
+implementations allow all exceptions to propagate, others catch them
+and set ios_base::badbit instead, still others catch some but let
+others propagate.
+</p>
+
+<p>
+The text also mentions that the functions may call setstate(failbit)
+(without actually saying on what object, but presumably the stream
+argument is meant). That may have been fine for
+basic_istream<>::sentry prior to issue <a href="lwg-defects.html#195">195</a>, since
+the function performs an input operation which may fail. However,
+issue <a href="lwg-defects.html#195">195</a> amends 27.6.1.1.2 , p2 to
+clarify that the function should actually call setstate(failbit |
+eofbit), so the sentence in p3 is redundant or even somewhat
+contradictory.
+</p>
+
+<p>
+The same sentence that appears in 27.6.2.3 , p3
+doesn't seem to be very meaningful for basic_istream<>::sentry
+which performs no input. It is actually rather misleading since it
+would appear to guide library implementers to calling
+setstate(failbit) when os.tie()->flush(), the only called function,
+throws an exception (typically, it's badbit that's set in response to
+such an event).
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following paragraph immediately after
+27.6.1.1.2 , p5</p>
+
+<blockquote>
+ <p>
+ If an exception is thrown during the preparation then ios::badbit
+ is turned on* in is's error state.
+ </p>
+
+ <p>
+ [Footnote: This is done without causing an ios::failure to be thrown.
+ --- end footnote]
+ </p>
+
+ <p>
+ If (is.exceptions() & ios_base::badbit)!= 0 then the exception is
+ rethrown.
+ </p>
+</blockquote>
+
+<p>And strike the following sentence from 27.6.1.1.2 , p5</p>
+
+<blockquote>
+ During preparation, the constructor may call setstate(failbit)
+ (which may throw ios_base::failure (lib.iostate.flags))
+</blockquote>
+
+<p>Add the following paragraph immediately after
+27.6.2.3 , p3</p>
+
+<blockquote>
+ <p>
+ If an exception is thrown during the preparation then ios::badbit
+ is turned on* in os's error state.
+ </p>
+
+ <p>
+ [Footnote: This is done without causing an ios::failure to be
+ thrown. --- end footnote]
+ </p>
+
+ <p>
+ If (os.exceptions() & ios_base::badbit)!= 0 then the exception
+ is rethrown.
+ </p>
+</blockquote>
+
+<p>And strike the following sentence from 27.6.2.3 , p3</p>
+
+<blockquote>
+ During preparation, the constructor may call setstate(failbit)
+ (which may throw ios_base::failure (lib.iostate.flags))
+</blockquote>
+
+<p>(Note that the removal of the two sentences means that the ctors
+will not be able to report the failure of any implementation-dependent
+operations referred to in footnotes 280 and 293, unless such
+operations throw an exception.)</p>
+
+<p><i>[
+Copenhagen: It was agreed that there was an issue here, but there was
+disagreement about the resolution. Some LWG members argued that a
+sentry's constructor should not catch exceptions, because sentries
+should only be used within (un)formatted input functions and that
+exception handling is the responsibility of those functions, not of
+the sentries.
+]</i></p>
+
+<hr>
+<a name="310"><h3>310. Is errno a macro?</h3></a><p>
+<b>Section:</b> 17.4.1.2 <a href="lib-intro.html#lib.headers"> [lib.headers]</a>, 19.3 <a href="lib-diagnostics.html#lib.errno"> [lib.errno]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 21 Mar 2001</p>
+ <p>
+ Exactly how should errno be declared in a conforming C++ header?
+ </p>
+
+ <p>
+ The C standard says in 7.1.4 that it is unspecified whether errno is a
+ macro or an identifier with external linkage. In some implementations
+ it can be either, depending on compile-time options. (E.g., on
+ Solaris in multi-threading mode, errno is a macro that expands to a
+ function call, but is an extern int otherwise. "Unspecified" allows
+ such variability.)
+ </p>
+
+ <p>The C++ standard:</p>
+ <ul>
+ <li>17.4.1.2 says in a note that errno must be macro in C. (false)</li>
+ <li>17.4.3.1.3 footnote 166 says errno is reserved as an external
+ name (true), and implies that it is an identifier.</li>
+ <li>19.3 simply lists errno as a macro (by what reasoning?) and goes
+ on to say that the contents of of C++ <errno.h> are the
+ same as in C, begging the question.</li>
+ <li>C.2, table 95 lists errno as a macro, without comment.</li>
+ </ul>
+
+ <p>I find no other references to errno.</p>
+
+ <p>We should either explicitly say that errno must be a macro, even
+ though it need not be a macro in C, or else explicitly leave it
+ unspecified. We also need to say something about namespace std.
+ A user who includes <cerrno> needs to know whether to write
+ <tt>errno</tt>, or <tt>::errno</tt>, or <tt>std::errno</tt>, or
+ else <cerrno> is useless.</p>
+
+ <p>Two acceptable fixes:</p>
+ <ul>
+ <li><p>errno must be a macro. This is trivially satisfied by adding<br>
+ #define errno (::std::errno)<br>
+ to the headers if errno is not already a macro. You then always
+ write errno without any scope qualification, and it always expands
+ to a correct reference. Since it is always a macro, you know to
+ avoid using errno as a local identifer.</p></li>
+ <li><p>errno is in the global namespace. This fix is inferior, because
+ ::errno is not guaranteed to be well-formed.</p></li>
+ </ul>
+
+ <p><i>[
+ This issue was first raised in 1999, but it slipped through
+ the cracks.
+ ]</i></p>
+<p><b>Proposed resolution:</b></p>
+ <p>Change the Note in section 17.4.1.2p5 from</p>
+
+ <blockquote>
+ Note: the names defined as macros in C include the following:
+ assert, errno, offsetof, setjmp, va_arg, va_end, and va_start.
+ </blockquote>
+
+ <p>to</p>
+
+ <blockquote>
+ Note: the names defined as macros in C include the following:
+ assert, offsetof, setjmp, va_arg, va_end, and va_start.
+ </blockquote>
+
+ <p>In section 19.3, change paragraph 2 from</p>
+
+ <blockquote>
+ The contents are the same as the Standard C library header
+ <errno.h>.
+ </blockquote>
+
+ <p>to</p>
+
+ <blockquote>
+ The contents are the same as the Standard C library header
+ <errno.h>, except that errno shall be defined as a macro.
+ </blockquote>
+<hr>
+<a name="311"><h3>311. Incorrect wording in basic_ostream class synopsis</h3></a><p>
+<b>Section:</b> 27.6.2.1 <a href="lib-iostreams.html#lib.ostream"> [lib.ostream]</a> <b>Status:</b> <a href="lwg-active.html#Review">Review</a> <b>Submitter:</b> Andy Sawyer <b>Date:</b> 21 Mar 2001</p>
+
+<p>In 27.6.2.1 , the synopsis of class basic_ostream says:</p>
+
+<pre>
+ // partial specializationss
+ template<class traits>
+ basic_ostream<char,traits>& operator<<( basic_ostream<char,traits>&,
+ const char * );
+</pre>
+
+<p>Problems:</p>
+<ul>
+<li>Too many 's's at the end of "specializationss" </li>
+<li>This is an overload, not a partial specialization</li>
+</ul>
+
+<p><b>Proposed resolution:</b></p>
+<p>In the synopsis in 27.6.2.1 , remove the
+<i>// partial specializationss</i> comment.</p>
+<hr>
+<a name="312"><h3>312. Table 27 is missing headers</h3></a><p>
+<b>Section:</b> 20 <a href="lib-utilities.html#lib.utilities"> [lib.utilities]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Ready</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 29 Mar 2001</p>
+<p>Table 27 in section 20 lists the header <memory> (only) for
+Memory (lib.memory) but neglects to mention the headers
+<cstdlib> and <cstring> that are discussed in 20.4.6 .</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add <cstdlib> and <cstring> to Table 27, in the same row
+as <memory>.</p>
+<hr>
+<a name="315"><h3>315. Bad "range" in list::unique complexity</h3></a><p>
+<b>Section:</b> 23.2.2.4 <a href="lib-containers.html#lib.list.ops"> [lib.list.ops]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Andy Sawyer <b>Date:</b> 1 May 2001</p>
+<p>
+23.2.2.4 , Para 21 describes the complexity of
+list::unique as: "If the range (last - first) is not empty, exactly
+(last - first) -1 applications of the corresponding predicate,
+otherwise no applications of the predicate)".
+</p>
+
+<p>
+"(last - first)" is not a range.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Change the "range" from (last - first) to [first, last). Change the
+complexity from "(last - first) -1 applications of the corresponding
+predicate" to "distance(first,last)-1 applications of the corresponding
+predicate.
+</p>
+<hr>
+<a name="316"><h3>316. Vague text in Table 69</h3></a><p>
+<b>Section:</b> 23.1.2 <a href="lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 4 May 2001</p>
+<p>Table 69 says this about a_uniq.insert(t):</p>
+
+<blockquote>
+inserts t if and only if there is no element in the container with key
+equivalent to the key of t. The bool component of the returned pair
+indicates whether the insertion takes place and the iterator component of the
+pair points to the element with key equivalent to the key of t.
+</blockquote>
+
+<p>The description should be more specific about exactly how the bool component
+indicates whether the insertion takes place.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the text in question to</p>
+
+<blockquote>
+...The bool component of the returned pair is true if and only if the insertion
+takes place...
+</blockquote>
+<hr>
+<a name="317"><h3>317. Instantiation vs. specialization of facets</h3></a><p>
+<b>Section:</b> 22 <a href="lib-locales.html#lib.localization"> [lib.localization]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 4 May 2001</p>
+<p>
+The localization section of the standard refers to specializations of
+the facet templates as instantiations even though the required facets
+are typically specialized rather than explicitly (or implicitly)
+instantiated. In the case of ctype<char> and
+ctype_byname<char> (and the wchar_t versions), these facets are
+actually required to be specialized. The terminology should be
+corrected to make it clear that the standard doesn't mandate explicit
+instantiation (the term specialization encompasses both explicit
+instantiations and specializations).
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In the following paragraphs, replace all occurrences of the word
+instantiation or instantiations with specialization or specializations,
+respectively:
+</p>
+
+<blockquote>
+22.1.1.1.1, p4, Table 52, 22.2.1.1, p2, 22.2.1.5, p3, 22.2.1.5.1, p5,
+22.2.1.5.2, p10, 22.2.2, p2, 22.2.3.1, p1, 22.2.3.1.2, p1, p2 and p3,
+22.2.4.1, p1, 22.2.4.1.2, p1, 22,2,5, p1, 22,2,6, p2, 22.2.6.3.2, p7, and
+Footnote 242.
+</blockquote>
+
+<p>And change the text in 22.1.1.1.1, p4 from</p>
+
+<blockquote>
+ An implementation is required to provide those instantiations
+ for facet templates identified as members of a category, and
+ for those shown in Table 52:
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+ An implementation is required to support those specializations...
+</blockquote>
+<hr>
+<a name="318"><h3>318. Misleading comment in definition of numpunct_byname</h3></a><p>
+<b>Section:</b> 22.2.3.2 <a href="lib-locales.html#lib.locale.numpunct.byname"> [lib.locale.numpunct.byname]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 12 May 2001</p>
+<p>The definition of the numpunct_byname template contains the following
+comment:</p>
+
+<pre>
+ namespace std {
+ template <class charT>
+ class numpunct_byname : public numpunct<charT> {
+ // this class is specialized for char and wchar_t.
+ ...
+</pre>
+
+<p>There is no documentation of the specializations and it seems
+conceivable that an implementation will not explicitly specialize the
+template at all, but simply provide the primary template.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove the comment from the text in 22.2.3.2 and from the proposed
+resolution of library issue <a href="lwg-active.html#228">228</a>.</p>
+<hr>
+<a name="319"><h3>319. Storage allocation wording confuses "Required behavior", "Requires"</h3></a><p>
+<b>Section:</b> 18.4.1.1 <a href="lib-support.html#lib.new.delete.single"> [lib.new.delete.single]</a>, 18.4.1.2 <a href="lib-support.html#lib.new.delete.array"> [lib.new.delete.array]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Beman Dawes <b>Date:</b> 15 May 2001</p>
+<p>The standard specifies 17.3.1.3 that "Required
+behavior" elements describe "the semantics of a function definition
+provided by either the implementation or a C++ program."</p>
+
+<p>The standard specifies 17.3.1.3 that "Requires"
+elements describe "the preconditions for calling the function."</p>
+
+<p>In the sections noted below, the current wording specifies
+"Required Behavior" for what are actually preconditions, and thus
+should be specified as "Requires".</p>
+
+<p><b>Proposed resolution:</b></p>
+
+<p>In 18.4.1.1 Para 12 Change:</p>
+<blockquote>
+ <p>Required behavior: accept a value of ptr that is null or that was
+ returned by an earlier call ...</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>Requires: the value of ptr be null or the value returned by an
+ earlier call ...</p>
+</blockquote>
+
+<p>In 18.4.1.2 Para 11 Change:</p>
+<blockquote>
+ <p>Required behavior: accept a value of ptr that is null or that was
+ returned by an earlier call ...</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>Requires: the value of ptr be null or the value returned by an
+ earlier call ...</p>
+</blockquote>
+
+<hr>
+<a name="320"><h3>320. list::assign overspecified</h3></a><p>
+<b>Section:</b> 23.2.2.1 <a href="lib-containers.html#lib.list.cons"> [lib.list.cons]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 17 May 2001</p>
+<p>
+Section 23.2.2.1, paragraphs 6-8 specify that list assign (both forms) have
+the "effects" of a call to erase followed by a call to insert.
+</p>
+
+<p>
+I would like to document that implementers have the freedom to implement
+assign by other methods, as long as the end result is the same and the
+exception guarantee is as good or better than the basic guarantee.
+</p>
+
+<p>
+The motivation for this is to use T's assignment operator to recycle
+existing nodes in the list instead of erasing them and reallocating
+them with new values. It is also worth noting that, with careful
+coding, most common cases of assign (everything but assignment with
+true input iterators) can elevate the exception safety to strong if
+T's assignment has a nothrow guarantee (with no extra memory cost).
+Metrowerks does this. However I do not propose that this subtlety be
+standardized. It is a QoI issue. </p>
+
+<p>Existing practise:
+Metrowerks and SGI recycle nodes, Dinkumware and Rogue Wave don't.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 23.2.2.1/7 from:</p>
+
+<blockquote>
+<p>Effects:</p>
+
+<pre>
+ erase(begin(), end());
+ insert(begin(), first, last);
+</pre>
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+<p>Effects: Replaces the contents of the list with the range [first, last).</p>
+<p>PostCondition: *this == list<T, Allocator>(first, last)</p>
+<p>Notes: If an exception is thrown, the contents of the list are
+indeterminate.</p>
+</blockquote>
+
+<p>Change 23.2.2.1/8 from:</p>
+
+<blockquote>
+<p>Effects:</p>
+<pre>
+ erase(begin(), end());
+ insert(begin(), n, t);
+</pre>
+</blockquote>
+<p>to:</p>
+
+<blockquote>
+<p>Effects: Replaces the contents of the list with n copies of t.</p>
+<p>PostCondition: *this == list<T, Allocator>(n, t)</p>
+<p>Notes: If an exception is thrown, the contents of the list are self
+consistent but indeterminate.</p>
+</blockquote>
+<hr>
+<a name="321"><h3>321. Typo in num_get</h3></a><p>
+<b>Section:</b> 22.2.2.1.2 <a href="lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Kevin Djang <b>Date:</b> 17 May 2001</p>
+<p>
+Section 22.2.2.1.2 at p7 states that "A length specifier is added to
+the conversion function, if needed, as indicated in Table 56."
+However, Table 56 uses the term "length modifier", not "length
+specifier".
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In 22.2.2.1.2 at p7, change the text "A length specifier is added ..."
+to be "A length modifier is added ..."
+</p>
+<hr>
+<a name="322"><h3>322. iterator and const_iterator should have the same value type</h3></a><p>
+<b>Section:</b> 23.1 <a href="lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 17 May 2001</p>
+<p>
+It's widely assumed that, if X is a container,
+iterator_traits<X::iterator>::value_type and
+iterator_traits<X::const_iterator>::value_type should both be
+X::value_type. However, this is nowhere stated. The language in
+Table 65 is not precise about the iterators' value types (it predates
+iterator_traits), and could even be interpreted as saying that
+iterator_traits<X::const_iterator>::value_type should be "const
+X::value_type".
+</p>
+
+<p>Related issue: <a href="lwg-closed.html#279">279</a>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In Table 65 ("Container Requirements"), change the return type for
+X::iterator to "iterator type whose value type is T". Change the
+return type for X::const_iterator to "constant iterator type whose
+value type is T".</p>
+<p><b>Rationale:</b></p>
+<p>
+This belongs as a container requirement, rather than an iterator
+requirement, because the whole notion of iterator/const_iterator
+pairs is specific to containers' iterator.
+</p>
+<p>
+It is existing practice that (for example)
+iterator_traits<list<int>::const_iterator>::value_type
+is "int", rather than "const int". This is consistent with
+the way that const pointers are handled: the standard already
+requires that iterator_traits<const int*>::value_type is int.
+</p>
+<hr>
+<a name="323"><h3>323. abs() overloads in different headers</h3></a><p>
+<b>Section:</b> 26.5 <a href="lib-numerics.html#lib.c.math"> [lib.c.math]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 4 June 2001</p>
+<p>Currently the standard mandates the following overloads of
+abs():</p>
+
+<pre>
+ abs(long), abs(int) in <cstdlib>
+
+ abs(float), abs(double), abs(long double) in <cmath>
+
+ template<class T> T abs(const complex<T>&) in <complex>
+
+ template<class T> valarray<T> abs(const valarray<T>&); in <valarray>
+</pre>
+
+<p>
+The problem is that having only some overloads visible of a function
+that works on "implicitly inter-convertible" types is dangerous in
+practice. The headers that get included at any point in a translation
+unit can change unpredictably during program
+development/maintenance. The wrong overload might be unintentionally
+selected.
+</p>
+
+<p>
+Currently, there is nothing that mandates the simultaneous visibility
+of these overloads. Indeed, some vendors have begun fastidiously
+reducing dependencies among their (public) headers as a QOI issue: it
+helps people to write portable code by refusing to compile unless all
+the correct headers are #included.
+</p>
+
+<p>The same issue may exist for other functions in the library.</p>
+<p><b>Proposed resolution:</b></p>
+<hr>
+<a name="324"><h3>324. Do output iterators have value types?</h3></a><p>
+<b>Section:</b> 24.1.2 <a href="lib-iterators.html#lib.output.iterators"> [lib.output.iterators]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 7 June 2001</p>
+
+<p>Table 73 suggests that output iterators have value types. It says
+defines the expression "*a = t". Additionally, although Table 73
+never lists "a = t" or "X(a) = t" in the "expressions" column, it
+contains a note saying that "a = t" and "X(a) = t" have equivalent
+(but nowhere specified!) semantics.</p>
+
+<p>According to 24.1/9, t is supposed to be "a value of value type
+T":</p>
+
+ <blockquote>
+ In the following sections, a and b denote values of X, n denotes a
+ value of the difference type Distance, u, tmp, and m denote
+ identifiers, r denotes a value of X&, t denotes a value of
+ value type T.
+ </blockquote>
+
+<p>Two other parts of the standard that are relevant to whether
+output iterators have value types:</p>
+
+<ul>
+ <li>24.1/1 says "All iterators i support the expression *i,
+ resulting in a value of some class, enumeration, or built-in type
+ T, called the value type of the iterator".</li>
+
+ <li>
+ 24.3.1/1, which says "In the case of an output iterator, the types
+ iterator_traits<Iterator>::difference_type
+ iterator_traits<Iterator>::value_type are both defined as void."
+ </li>
+</ul>
+
+<p>The first of these passages suggests that "*i" is supposed to
+return a useful value, which contradicts the note in 24.1.2/2 saying
+that the only valid use of "*i" for output iterators is in an
+expression of the form "*i = t". The second of these passages appears
+to contradict Table 73, because it suggests that "*i"'s return value
+should be void. The second passage is also broken in the case of a an
+iterator type, like non-const pointers, that satisfies both the output
+iterator requirements and the forward iterator requirements.</p>
+
+<p>What should the standard say about "*i's" return value when i is an
+output iterator, and what should it say about that t is in the
+expression "*i = t"? Finally, should the standard say anything about
+output iterators' pointer and reference types?</p>
+
+<p><b>Proposed resolution:</b></p>
+
+<p>A sketch of one proposed resolution, without language: Make it
+clear that the notion of "value type" does not apply to output
+iterators.</p>
+
+<blockquote>
+Put an "except for output iterators" qualification in 24.1/1; remove
+the note in table 73 about "a = t" and "X(a) = t"; put language in
+24.1.2 paragraph 1 saying that "t" is a value of whatever type or
+types for which "*i = t" is defined and that an output iterator need
+not have a unique value type; change 24.3.1/1 to say that an output
+iterator may, but need not, define
+iterator_traits<Iterator>::difference_type
+iterator_traits<Iterator>::value_type as void.
+</blockquote>
+
+<p>A sketch of an alternate proposed resolution, also without
+language: Require every output iterator to have a value type, just
+like other kinds of iterators.</p>
+
+<blockquote>
+Put an "except for output iterators" qualification in 24.1/1; remove
+the note in table 73 about "a = t" and "X(a) = t"; put language in
+24.1.2 paragraph 1 saying that an output iterator's value type is the
+type for which "*i = t" is defined; remove the note in 24.3.1/1 saying
+that iterator_traits<>::value_type is void for an output
+iterator; change all of the predefined output iterators
+(ostream_iterator, ostreambuf_iterator, back_insert_iterator,
+front_insert_iterator, insert_iterator) so that they have non-void
+value types.
+</blockquote>
+
+<hr>
+<a name="325"><h3>325. Misleading text in moneypunct<>::do_grouping</h3></a><p>
+<b>Section:</b> 22.2.6.3.2 <a href="lib-locales.html#lib.locale.moneypunct.virtuals"> [lib.locale.moneypunct.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 02 Jul 2001</p>
+<p>The Returns clause in 22.2.6.3.2, p3 says about
+moneypunct<charT>::do_grouping()
+</p>
+
+<blockquote>
+ Returns: A pattern defined identically as the result of
+ numpunct<charT>::do_grouping().241)
+</blockquote>
+
+<p>Footnote 241 then reads</p>
+
+<blockquote>
+ This is most commonly the value "\003" (not "3").
+</blockquote>
+
+<p>
+The returns clause seems to imply that the two member functions must
+return an identical value which in reality may or may not be true,
+since the facets are usually implemented in terms of struct std::lconv
+and return the value of the grouping and mon_grouping, respectively.
+The footnote also implies that the member function of the moneypunct
+facet (rather than the overridden virtual functions in moneypunct_byname)
+most commonly return "\003", which contradicts the C standard which
+specifies the value of "" for the (most common) C locale.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Replace the text in Returns clause in 22.2.6.3.2, p3 with the following:</p>
+
+<blockquote>
+ Returns: A pattern defined identically as, but not necessarily
+ equal to, the result of numpunct<charT>::do_grouping().241)
+</blockquote>
+
+<p>and replace the text in Footnote 241 with the following:</p>
+
+<blockquote>
+ The moneypunct facet (or its derivative) installed in named locales
+ other than "C" will most commonly return the value "\003" (not "3").
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>
+Note that the proposed resolution is sufficiently vague to allow
+implementations to implement the behavior of both moneypunct and
+moneypunct_byname to be implemented by the base. This may or may
+not be desirable depending on whether we want the base behavior
+to strictly reflect the "C" locale (only) and the derived behavior
+to implement the behavior specific to the named locales. This
+distinction would be detectable by obtaining a reference to
+moneypunct_byname, say mp, and calling mp.do_grouping() or
+mp.moneypunct<charT>::do_grouping() to get one or the other.
+</p>
+<hr>
+<a name="326"><h3>326. Missing typedef in moneypunct_byname</h3></a><p>
+<b>Section:</b> 22.2.6.4 <a href="lib-locales.html#lib.locale.moneypunct.byname"> [lib.locale.moneypunct.byname]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 05 Jul 2001</p>
+<p>The definition of the moneypunct facet contains the typedefs char_type
+and string_type. Only one of these names, string_type, is defined in
+the derived facet, moneypunct_byname.</p>
+<p><b>Proposed resolution:</b></p>
+<p>For consistency with the numpunct facet, add a typedef for
+char_type to the definition of the moneypunct_byname facet in
+22.2.6.4 .</p>
+<hr>
+<a name="327"><h3>327. Typo in time_get facet in table 52</h3></a><p>
+<b>Section:</b> 22.1.1.1.1 <a href="lib-locales.html#lib.locale.category"> [lib.locale.category]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Tiki Wan <b>Date:</b> 06 Jul 2001</p>
+<p>The <tt>wchar_t</tt> versions of <tt>time_get</tt> and
+<tt>time_get_byname</tt> are listed incorrectly in table 52,
+required instantiations. In both cases the second template
+parameter is given as OutputIterator. It should instead be
+InputIterator, since these are input facets.</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In table 52, required instantiations, in
+22.1.1.1.1 , change</p>
+<pre>
+ time_get<wchar_t, OutputIterator>
+ time_get_byname<wchart, OutputIterator>
+</pre>
+<p>to</p>
+<pre>
+ time_get<wchar_t, InputIterator>
+ time_get_byname<wchart, InputIterator>
+</pre>
+<hr>
+<a name="328"><h3>328. Bad sprintf format modifier in money_put<>::do_put()</h3></a><p>
+<b>Section:</b> 22.2.6.2.2 <a href="lib-locales.html#lib.locale.money.put.virtuals"> [lib.locale.money.put.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 07 Jul 2001</p>
+<p>The sprintf format string , "%.01f" (that's the digit one), in the
+description of the do_put() member functions of the money_put facet in
+22.2.6.2.2, p1 is incorrect. First, the f format specifier is wrong
+for values of type long double, and second, the precision of 01
+doesn't seem to make sense. What was most likely intended was
+"%.0Lf"., that is a precision of zero followed by the L length
+modifier.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the format string to "%.0Lf".</p>
+<hr>
+<a name="329"><h3>329. vector capacity, reserve and reallocation</h3></a><p>
+<b>Section:</b> 23.2.4.2 <a href="lib-containers.html#lib.vector.capacity"> [lib.vector.capacity]</a>, 23.2.4.3 <a href="lib-containers.html#lib.vector.modifiers"> [lib.vector.modifiers]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Anthony Williams <b>Date:</b> 13 Jul 2001</p>
+<p>
+There is an apparent contradiction about which circumstances can cause
+a reallocation of a vector in Section 23.2.4.2 and
+section 23.2.4.3 .
+</p>
+
+<p>23.2.4.2p5 says:</p>
+<blockquote>
+Notes: Reallocation invalidates all the references, pointers, and iterators
+referring to the elements in the sequence. It is guaranteed that no
+reallocation takes place during insertions that happen after a call to
+reserve() until the time when an insertion would make the size of the vector
+greater than the size specified in the most recent call to reserve().
+</blockquote>
+
+<p>Which implies if I do</p>
+
+<pre>
+ std::vector<int> vec;
+ vec.reserve(23);
+ vec.reserve(0);
+ vec.insert(vec.end(),1);
+</pre>
+
+<p>then the implementation may reallocate the vector for the insert,
+as the size specified in the previous call to reserve was zero.</p>
+
+<p>However, the previous paragraphs (23.2.4.2, p1-2) state:</p>
+<blockquote>
+<p>
+(capacity) Returns: The total number of elements the vector
+can hold without requiring reallocation
+</p>
+<p>
+...After reserve(), capacity() is greater or equal to the
+argument of reserve if reallocation happens; and equal to the previous value
+of capacity() otherwise...
+</p>
+</blockquote>
+
+<p>
+This implies that vec.capacity() is still 23, and so the insert()
+should not require a reallocation, as vec.size() is 0. This is backed
+up by 23.2.4.3p1:
+</p>
+<blockquote>
+(insert) Notes: Causes reallocation if the new size is greater than the old
+capacity.
+</blockquote>
+
+<p>
+Though this doesn't rule out reallocation if the new size is less
+than the old capacity, I think the intent is clear.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Change the wording of 23.2.4.5p5 to:</p>
+
+<blockquote>
+Notes: Reallocation invalidates all the references, pointers, and
+iterators referring to the elements in the sequence. It is guaranteed
+that no reallocation takes place during insertions that happen after a
+call to reserve() until the time when an insertion would make the size
+of the vector greater than the value of capacity() after the most
+recent call to reserve().
+</blockquote>
+
+<hr>
+<a name="330"><h3>330. Misleading "exposition only" value in class locale definition</h3></a><p>
+<b>Section:</b> 22.1.1 <a href="lib-locales.html#lib.locale"> [lib.locale]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 15 Jul 2001</p>
+<p>
+The "exposition only" value of the std::locale::none constant shown in
+the definition of class locale is misleading in that it on many
+systems conflicts with the value assigned to one if the LC_XXX
+constants (specifically, LC_COLLATE on AIX, LC_ALL on HP-UX, LC_CTYPE
+on Linux and SunOS). This causes incorrect behavior when such a
+constant is passed to one of the locale member functions that accept a
+locale::category argument and interpret it as either the C LC_XXX
+constant or a bitmap of locale::category values. At least three major
+implementations adopt the suggested value without a change and
+consequently suffer from this problem.
+</p>
+
+<p>
+For instance, the following code will (presumably) incorrectly copy facets
+belonging to the collate category from the German locale on AIX:
+</p>
+
+<pre>
+ std::locale l (std::locale ("C"), "de_DE", std::locale::none);
+</pre>
+<p><b>Proposed resolution:</b></p>
+<p>
+Change the value from 0 to some other bit value, say 0x400, distinct
+from any of the other values shown.
+</p>
+<hr>
+<a name="331"><h3>331. bad declaration of destructor for ios_base::failure</h3></a><p>
+<b>Section:</b> 27.4.2.1.1 <a href="lib-iostreams.html#lib.ios::failure"> [lib.ios::failure]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> PremAnand M. Rao <b>Date:</b> 23 Aug 2001</p>
+<p>
+With the change in 17.4.4.8 to state
+ "An implementation may strengthen the exception-specification for a
+ non-virtual function by removing listed exceptions."
+(issue <a href="lwg-defects.html#119">119</a>)
+and the following declaration of ~failure() in ios_base::failure
+</p>
+<pre>
+ namespace std {
+ class ios_base::failure : public exception {
+ public:
+ ...
+ virtual ~failure();
+ ...
+ };
+ }
+</pre>
+<p>the class failure cannot be implemented since in 18.6.1 the destructor of class exception has an empty
+exception specification:</p>
+<pre>
+ namespace std {
+ class exception {
+ public:
+ ...
+ virtual ~exception() throw();
+ ...
+ };
+ }
+</pre>
+<p><b>Proposed resolution:</b></p>
+<p>Two alternatives:</p>
+<ol>
+<li>Change the declaration of ~failure() to virtual ~failure() throw();</li>
+<li>Remove the declaration of ~failure().</li>
+</ol>
+<hr>
+<a name="332"><h3>332. Consider adding increment and decrement operators to std::fpos< T > </h3></a><p>
+<b>Section:</b> 27.4.3 <a href="lib-iostreams.html#lib.fpos"> [lib.fpos]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> PremAnand M. Rao <b>Date:</b> 27 Aug 2001</p>
+<p>
+Increment and decrement operators are missing from
+Table 88 -- Position type requirements in 27.4.3 .
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Table 88 (section 27.4.3) -- Position type requirements
+be updated to include increment and decrement operators.
+</p>
+
+<pre>
+expression return type operational note
+
+++p fpos& p += O(1)
+p++ fpos { P tmp = p;
+ ++p;
+ return tmp; }
+--p fpos& p -= O(1)
+p-- fpos { P tmp = p;
+ --p;
+ return tmp; }
+</pre>
+
+<hr>
+<a name="333"><h3>333. does endl imply synchronization with the device?</h3></a><p>
+<b>Section:</b> 27.6.2.7 <a href="lib-iostreams.html#lib.ostream.manip"> [lib.ostream.manip]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> PremAnand M. Rao <b>Date:</b> 27 Aug 2001</p>
+<p>A footnote in 27.6.2.7 states:</p>
+<blockquote>
+ [Footnote: The effect of executing cout << endl is to insert a
+ newline character in the output sequence controlled by cout, then
+ synchronize it with any external file with which it might be
+ associated. --- end foonote]
+</blockquote>
+
+<p>
+Does the term "file" here refer to the external device?
+This leads to some implementation ambiguity on systems with fully
+buffered files where a newline does not cause a flush to the device.
+</p>
+
+<p>
+Choosing to sync with the device leads to significant performance
+penalties for each call to endl, while not sync-ing leads to
+errors under special circumstances.
+</p>
+
+<p>
+I could not find any other statement that explicitly defined
+the behavior one way or the other.
+</p>
+<p><b>Proposed resolution:</b></p>
+<hr>
+<a name="334"><h3>334. map::operator[] specification forces inefficient implementation</h3></a><p>
+<b>Section:</b> 23.3.1.2 <a href="lib-containers.html#lib.map.access"> [lib.map.access]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Andrea Griffini <b>Date:</b> 02 Sep 2001</p>
+<p>
+The current standard describes map::operator[] using a
+code example. That code example is however quite
+inefficient because it requires several useless copies
+of both the passed key_type value and of default
+constructed mapped_type instances.
+My opinion is that was not meant by the comitee to
+require all those temporary copies.
+</p>
+
+<p>Currently map::operator[] behaviour is specified as: </p>
+<pre>
+ Returns:
+ (*((insert(make_pair(x, T()))).first)).second.
+</pre>
+
+<p>
+This specification however uses make_pair that is a
+template function of which parameters in this case
+will be deduced being of type const key_type& and
+const T&. This will create a pair<key_type,T> that
+isn't the correct type expected by map::insert so
+another copy will be required using the template
+conversion constructor available in pair to build
+the required pair<const key_type,T> instance.
+</p>
+
+<p>If we consider calling of key_type copy constructor
+and mapped_type default constructor and copy
+constructor as observable behaviour (as I think we
+should) then the standard is in this place requiring
+two copies of a key_type element plus a default
+construction and two copy construction of a mapped_type
+(supposing the addressed element is already present
+in the map; otherwise at least another copy
+construction for each type).
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>A simple (half) solution would be replacing the description with:</p>
+<pre>
+ Returns:
+ (*((insert(value_type(x, T()))).first)).second.
+</pre>
+
+<p>This will remove the wrong typed pair construction that
+requires one extra copy of both key and value.</p>
+
+<p>However still the using of map::insert requires temporary
+objects while the operation, from a logical point of view,
+doesn't require any. </p>
+
+<p>I think that a better solution would be leaving free an
+implementer to use a different approach than map::insert
+that, because of its interface, forces default constructed
+temporaries and copies in this case.
+The best solution in my opinion would be just requiring
+map::operator[] to return a reference to the mapped_type
+part of the contained element creating a default element
+with the specified key if no such an element is already
+present in the container. Also a logarithmic complexity
+requirement should be specified for the operation.
+</p>
+
+<p>
+This would allow library implementers to write alternative
+implementations not using map::insert and reaching optimal
+performance in both cases of the addressed element being
+present or absent from the map (no temporaries at all and
+just the creation of a new pair inside the container if
+the element isn't present).
+Some implementer has already taken this option but I think
+that the current wording of the standard rules that as
+non-conforming.
+</p>
+
+<p>
+Note that this is a "relaxing" of requirment and won't
+make any currently conforming implementation on this
+point to become non-conforming because of the change.
+</p>
+
+<p>
+There is a small risk that current code may be depending
+on the number of temporaries created by map::operator[];
+but I think that such dependencies would be present only
+in code that is most probably already non portable as
+the number of copies of parameters isn't guaranteed by
+the standard (in the current wording there's just an
+implicit *minimum* number of required copies).
+</p>
+
+<hr>
+<a name="335"><h3>335. minor issue with char_traits, table 37</h3></a><p>
+<b>Section:</b> 21.1.1 <a href="lib-strings.html#lib.char.traits.require"> [lib.char.traits.require]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a> <b>Submitter:</b> Andy Sawyer <b>Date:</b> 06 Sep 2001</p>
+<p>
+Table 37, in 21.1.1 , descibes char_traits::assign
+as:
+</p>
+<pre>
+ X::assign(c,d) assigns c = d.
+</pre>
+
+<p>And para 1 says:</p>
+
+<blockquote>
+ [...] c and d denote values of type CharT [...]
+</blockquote>
+
+<p>
+Naturally, if c and d are <i>values</i>, then the assignment is
+(effectively) meaningless. It's clearly intended that (in the case of
+assign, at least), 'c' is intended to be a reference type.
+</p>
+
+<p>I did a quick survey of the four implementations I happened to have
+lying around, and sure enough they all have signatures:</p>
+<pre>
+ assign( charT&, const charT& );
+</pre>
+
+<p>(or the equivalent). It's also described this way in Nico's book.
+(Not to mention the synopses of char_traits<char> in 21.1.3.1
+and char_traits<wchar_t> in 21.1.3.2...)
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following to 21.1.1 para 1:</p>
+<blockquote>
+ r denotes a reference to CharT
+</blockquote>
+
+<p>and change the description of assign in the table to:</p>
+<pre>
+ X::assign(r,d) assigns r = d
+</pre>
+<p>----- End of document -----</p>
+</body>
+</html>
--- /dev/null
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head><title>C++ Standard Library Defect Report List</title></head>
+<body bgcolor="#ffffff" text="#000000">
+<table>
+<tr>
+<td align="left">Doc. no.</td>
+<td align="left">J16/01-0032 = WG21 N1318</td>
+</tr>
+<tr>
+<td align="left">Date:</td>
+<td align="left">11 Sep 2001</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">Matt Austern <austern@research.att.com></td>
+</tr>
+</table>
+<h1>C++ Standard Library Defect Report List (Revision 19)</h1>
+ <p>Reference ISO/IEC IS 14882:1998(E)</p>
+ <p>Also see:</p>
+ <ul>
+ <li>
+<a href="lwg-toc.html">Table of Contents</a> for all library issues.</li>
+ <li>
+<a href="lwg-index.html">Index by Section</a> for all library issues.</li>
+ <li>
+<a href="lwg-status.html">Index by Status</a> for all library issues.</li>
+ <li><a href="lwg-active.html">Library Active Issues List</a></li>
+ <li><a href="lwg-closed.html">Library Closed Issues List</a></li>
+ </ul>
+ <p>This document contains only library issues which have been closed
+ by the Library Working Group (LWG) after being found to be defects
+ in the standard. That is, issues which have a status of <a href="lwg-active.html#DR">DR</a>, <a href="lwg-active.html#TC">TC</a>, or <a href="lwg-active.html#RR">RR</a>. See the
+ <a href="lwg-closed.html">Library Closed Issues List</a> for issues closed as non-defects. See the
+ <a href="lwg-active.html">Library Active Issues List</a> for active issues and more information. The
+ introductory material in that document also applies to this
+ document.</p>
+<h2>Revision History</h2>
+<ul>
+<li>R19:
+Pre-Redmond mailing. Added new issues
+<a href="lwg-active.html#323">323</a>-<a href="lwg-active.html#335">335</a>.
+</li>
+<li>R18:
+Post-Copenhagen mailing; reflects actions taken in Copenhagen.
+Added new issues <a href="lwg-active.html#312">312</a>-<a href="lwg-active.html#317">317</a>, and discussed
+new issues <a href="lwg-active.html#271">271</a>-<a href="lwg-closed.html#314">314</a>.
+
+Changed status of issues
+<a href="lwg-defects.html#103">103</a> <a href="lwg-defects.html#118">118</a> <a href="lwg-defects.html#136">136</a> <a href="lwg-defects.html#153">153</a>
+<a href="lwg-defects.html#165">165</a> <a href="lwg-defects.html#171">171</a> <a href="lwg-defects.html#183">183</a> <a href="lwg-defects.html#184">184</a>
+<a href="lwg-defects.html#185">185</a> <a href="lwg-defects.html#186">186</a> <a href="lwg-defects.html#214">214</a> <a href="lwg-defects.html#221">221</a>
+<a href="lwg-defects.html#234">234</a> <a href="lwg-defects.html#237">237</a> <a href="lwg-defects.html#243">243</a> <a href="lwg-defects.html#248">248</a>
+<a href="lwg-defects.html#251">251</a> <a href="lwg-defects.html#252">252</a> <a href="lwg-defects.html#256">256</a> <a href="lwg-defects.html#260">260</a>
+<a href="lwg-defects.html#261">261</a> <a href="lwg-defects.html#262">262</a> <a href="lwg-defects.html#263">263</a> <a href="lwg-defects.html#265">265</a>
+<a href="lwg-defects.html#268">268</a>
+to DR.
+
+Changed status of issues
+<a href="lwg-active.html#49">49</a> <a href="lwg-active.html#109">109</a> <a href="lwg-active.html#117">117</a> <a href="lwg-active.html#182">182</a>
+<a href="lwg-active.html#228">228</a> <a href="lwg-active.html#230">230</a> <a href="lwg-active.html#232">232</a> <a href="lwg-active.html#235">235</a>
+<a href="lwg-active.html#238">238</a> <a href="lwg-active.html#241">241</a> <a href="lwg-active.html#242">242</a> <a href="lwg-active.html#250">250</a>
+<a href="lwg-active.html#259">259</a> <a href="lwg-active.html#264">264</a> <a href="lwg-active.html#266">266</a> <a href="lwg-active.html#267">267</a>
+<a href="lwg-active.html#271">271</a> <a href="lwg-active.html#272">272</a> <a href="lwg-active.html#273">273</a> <a href="lwg-active.html#275">275</a>
+<a href="lwg-active.html#281">281</a> <a href="lwg-active.html#284">284</a> <a href="lwg-active.html#285">285</a> <a href="lwg-active.html#286">286</a>
+<a href="lwg-active.html#288">288</a> <a href="lwg-active.html#292">292</a> <a href="lwg-active.html#295">295</a> <a href="lwg-active.html#297">297</a>
+<a href="lwg-active.html#298">298</a> <a href="lwg-active.html#301">301</a> <a href="lwg-active.html#303">303</a> <a href="lwg-active.html#306">306</a>
+<a href="lwg-active.html#307">307</a> <a href="lwg-active.html#308">308</a> <a href="lwg-active.html#312">312</a>
+to Ready.
+
+Closed issues
+<a href="lwg-closed.html#111">111</a> <a href="lwg-closed.html#277">277</a> <a href="lwg-closed.html#279">279</a> <a href="lwg-closed.html#287">287</a>
+<a href="lwg-closed.html#289">289</a> <a href="lwg-closed.html#293">293</a> <a href="lwg-closed.html#302">302</a> <a href="lwg-closed.html#313">313</a>
+<a href="lwg-closed.html#314">314</a>
+as NAD.
+
+</li>
+<li>R17:
+Pre-Copenhagen mailing. Converted issues list to XML. Added proposed
+resolutions for issues <a href="lwg-active.html#49">49</a>, <a href="lwg-active.html#76">76</a>, <a href="lwg-active.html#91">91</a>, <a href="lwg-active.html#235">235</a>, <a href="lwg-active.html#250">250</a>, <a href="lwg-active.html#267">267</a>.
+Added new issues <a href="lwg-active.html#278">278</a>-<a href="lwg-active.html#311">311</a>.
+</li>
+<li>R16:
+post-Toronto mailing; reflects actions taken in Toronto. Added new
+issues <a href="lwg-defects.html#265">265</a>-<a href="lwg-closed.html#277">277</a>. Changed status of issues
+<a href="lwg-defects.html#3">3</a>, <a href="lwg-defects.html#8">8</a>, <a href="lwg-defects.html#9">9</a>, <a href="lwg-defects.html#19">19</a>,
+<a href="lwg-defects.html#26">26</a>, <a href="lwg-defects.html#31">31</a>, <a href="lwg-defects.html#61">61</a>,
+<a href="lwg-defects.html#63">63</a>, <a href="lwg-defects.html#86">86</a>, <a href="lwg-defects.html#108">108</a>,
+<a href="lwg-defects.html#112">112</a>, <a href="lwg-defects.html#114">114</a>, <a href="lwg-defects.html#115">115</a>,
+<a href="lwg-defects.html#122">122</a>, <a href="lwg-defects.html#127">127</a>, <a href="lwg-defects.html#129">129</a>,
+<a href="lwg-defects.html#134">134</a>, <a href="lwg-defects.html#137">137</a>, <a href="lwg-defects.html#142">142</a>,
+<a href="lwg-defects.html#144">144</a>, <a href="lwg-defects.html#146">146</a>, <a href="lwg-defects.html#147">147</a>,
+<a href="lwg-defects.html#159">159</a>, <a href="lwg-defects.html#164">164</a>, <a href="lwg-defects.html#170">170</a>,
+<a href="lwg-defects.html#181">181</a>, <a href="lwg-defects.html#199">199</a>, <a href="lwg-defects.html#208">208</a>,
+<a href="lwg-defects.html#209">209</a>, <a href="lwg-defects.html#210">210</a>, <a href="lwg-defects.html#211">211</a>,
+<a href="lwg-defects.html#212">212</a>, <a href="lwg-defects.html#217">217</a>, <a href="lwg-defects.html#220">220</a>,
+<a href="lwg-defects.html#222">222</a>, <a href="lwg-defects.html#223">223</a>, <a href="lwg-defects.html#224">224</a>,
+<a href="lwg-defects.html#227">227</a> to "DR". Reopened issue <a href="lwg-active.html#23">23</a>. Reopened
+issue <a href="lwg-active.html#187">187</a>. Changed issues <a href="lwg-closed.html#2">2</a> and
+<a href="lwg-closed.html#4">4</a> to NAD. Fixed a typo in issue <a href="lwg-defects.html#17">17</a>. Fixed
+issue <a href="lwg-defects.html#70">70</a>: signature should be changed both places it
+appears. Fixed issue <a href="lwg-defects.html#160">160</a>: previous version didn't fix
+the bug in enough places.
+</li>
+<li>R15:
+pre-Toronto mailing. Added issues
+<a href="lwg-active.html#233">233</a>-<a href="lwg-active.html#264">264</a>. Some small HTML formatting
+changes so that we pass Weblint tests.
+</li>
+<li>R14:
+post-Tokyo II mailing; reflects committee actions taken in
+Tokyo. Added issues <a href="lwg-active.html#228">228</a> to <a href="lwg-active.html#232">232</a>. (00-0019R1/N1242)
+</li>
+<li>R13:
+pre-Tokyo II updated: Added issues <a href="lwg-defects.html#212">212</a> to <a href="lwg-defects.html#227">227</a>.
+</li>
+<li>R12:
+pre-Tokyo II mailing: Added issues <a href="lwg-defects.html#199">199</a> to
+<a href="lwg-defects.html#211">211</a>. Added "and paragraph 5" to the proposed resolution
+of issue <a href="lwg-defects.html#29">29</a>. Add further rationale to issue
+<a href="lwg-closed.html#178">178</a>.
+</li>
+<li>R11:
+post-Kona mailing: Updated to reflect LWG and full committee actions
+in Kona (99-0048/N1224). Note changed resolution of issues
+<a href="lwg-closed.html#4">4</a> and <a href="lwg-defects.html#38">38</a>. Added issues <a href="lwg-closed.html#196">196</a>
+to <a href="lwg-active.html#198">198</a>. Closed issues list split into "defects" and
+"closed" documents. Changed the proposed resolution of issue
+<a href="lwg-closed.html#4">4</a> to NAD, and changed the wording of proposed resolution
+of issue <a href="lwg-defects.html#38">38</a>.
+</li>
+<li>R10:
+pre-Kona updated. Added proposed resolutions <a href="lwg-defects.html#83">83</a>,
+<a href="lwg-defects.html#86">86</a>, <a href="lwg-active.html#91">91</a>, <a href="lwg-active.html#92">92</a>,
+<a href="lwg-active.html#109">109</a>. Added issues <a href="lwg-closed.html#190">190</a> to
+<a href="lwg-defects.html#195">195</a>. (99-0033/D1209, 14 Oct 99)
+</li>
+<li>R9:
+pre-Kona mailing. Added issues <a href="lwg-closed.html#140">140</a> to
+<a href="lwg-defects.html#189">189</a>. Issues list split into separate "active" and
+"closed" documents. (99-0030/N1206, 25 Aug 99)
+</li>
+<li>R8:
+post-Dublin mailing. Updated to reflect LWG and full committee actions
+in Dublin. (99-0016/N1193, 21 Apr 99)
+</li>
+<li>R7:
+pre-Dublin updated: Added issues <a href="lwg-closed.html#130">130</a>, <a href="lwg-closed.html#131">131</a>,
+<a href="lwg-defects.html#132">132</a>, <a href="lwg-defects.html#133">133</a>, <a href="lwg-defects.html#134">134</a>,
+<a href="lwg-closed.html#135">135</a>, <a href="lwg-defects.html#136">136</a>, <a href="lwg-defects.html#137">137</a>,
+<a href="lwg-closed.html#138">138</a>, <a href="lwg-defects.html#139">139</a> (31 Mar 99)
+</li>
+<li>R6:
+pre-Dublin mailing. Added issues <a href="lwg-defects.html#127">127</a>, <a href="lwg-closed.html#128">128</a>,
+and <a href="lwg-defects.html#129">129</a>. (99-0007/N1194, 22 Feb 99)
+</li>
+<li>R5:
+update issues <a href="lwg-defects.html#103">103</a>, <a href="lwg-defects.html#112">112</a>; added issues
+<a href="lwg-defects.html#114">114</a> to <a href="lwg-defects.html#126">126</a>. Format revisions to prepare
+for making list public. (30 Dec 98)
+</li>
+<li>R4:
+post-Santa Cruz II updated: Issues <a href="lwg-defects.html#110">110</a>,
+<a href="lwg-closed.html#111">111</a>, <a href="lwg-defects.html#112">112</a>, <a href="lwg-closed.html#113">113</a> added, several
+issues corrected. (22 Oct 98)
+</li>
+<li>R3:
+post-Santa Cruz II: Issues <a href="lwg-closed.html#94">94</a> to <a href="lwg-active.html#109">109</a>
+added, many issues updated to reflect LWG consensus (12 Oct 98)
+</li>
+<li>R2:
+pre-Santa Cruz II: Issues <a href="lwg-closed.html#73">73</a> to <a href="lwg-closed.html#93">93</a> added,
+issue <a href="lwg-defects.html#17">17</a> updated. (29 Sep 98)
+</li>
+<li>R1:
+Correction to issue <a href="lwg-defects.html#55">55</a> resolution, <a href="lwg-defects.html#60">60</a> code
+format, <a href="lwg-defects.html#64">64</a> title. (17 Sep 98)
+</li>
+</ul>
+<h2>Defect Reports</h2>
+<hr>
+<a name="1"><h3>1. C library linkage editing oversight</h3></a><p>
+<b>Section:</b> 17.4.2.2 <a href="lib-intro.html#lib.using.linkage"> [lib.using.linkage]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Beman Dawes <b>Date:</b> 16 Nov 1997</p>
+<p>The change specified in the proposed resolution below did not make
+it into the Standard. This change was accepted in principle at the
+London meeting, and the exact wording below was accepted at the
+Morristown meeting.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 17.4.2.2 paragraph 2
+from:</p>
+
+<blockquote>
+ <p>It is unspecified whether a name from the Standard C library
+ declared with external linkage has either extern "C" or
+ extern "C++" linkage.</p>
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ <p>Whether a name from the Standard C library declared with external
+ linkage has extern "C" or extern "C++" linkage
+ is implementation defined. It is recommended that an implementation
+ use extern "C++" linkage for this purpose.</p>
+</blockquote>
+<hr>
+<a name="3"><h3>3. Atexit registration during atexit() call is not described</h3></a><p>
+<b>Section:</b> 18.3 <a href="lib-support.html#lib.support.start.term"> [lib.support.start.term]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 12 Dec 1997</p>
+<p>We appear not to have covered all the possibilities of
+ exit processing with respect to
+atexit registration. <br>
+<br>
+Example 1: (C and C++)</p>
+
+<pre> #include <stdlib.h>
+ void f1() { }
+ void f2() { atexit(f1); }
+
+ int main()
+ {
+ atexit(f2); // the only use of f2
+ return 0; // for C compatibility
+ }</pre>
+
+<p>At program exit, f2 gets called due to its registration in
+main. Running f2 causes f1 to be newly registered during the exit
+processing. Is this a valid program? If so, what are its
+semantics?</p>
+
+<p>
+Interestingly, neither the C standard, nor the C++ draft standard nor
+the forthcoming C9X Committee Draft says directly whether you can
+register a function with atexit during exit processing.</p>
+
+<p>
+All 3 standards say that functions are run in reverse order of their
+registration. Since f1 is registered last, it ought to be run first,
+but by the time it is registered, it is too late to be first.</p>
+
+<p>If the program is valid, the standards are self-contradictory about
+its semantics.</p>
+
+<p>Example 2: (C++ only)</p>
+
+<pre>
+ void F() { static T t; } // type T has a destructor
+
+ int main()
+ {
+ atexit(F); // the only use of F
+ }
+</pre>
+
+<p>Function F registered with atexit has a local static variable t,
+and F is called for the first time during exit processing. A local
+static object is initialized the first time control flow passes
+through its definition, and all static objects are destroyed during
+exit processing. Is the code valid? If so, what are its semantics?</p>
+
+<p>
+Section 18.3 "Start and termination" says that if a function
+F is registered with atexit before a static object t is initialized, F
+will not be called until after t's destructor completes.</p>
+
+<p>
+In example 2, function F is registered with atexit before its local
+static object O could possibly be initialized. On that basis, it must
+not be called by exit processing until after O's destructor
+completes. But the destructor cannot be run until after F is called,
+since otherwise the object could not be constructed in the first
+place.</p>
+
+<p>If the program is valid, the standard is self-contradictory about
+its semantics.</p>
+
+<p>I plan to submit Example 1 as a public comment on the C9X CD, with
+a recommendation that the results be undefined. (Alternative: make it
+unspecified. I don't think it is worthwhile to specify the case where
+f1 itself registers additional functions, each of which registers
+still more functions.)</p>
+
+<p>I think we should resolve the situation in the whatever way the C
+committee decides. </p>
+
+<p>For Example 2, I recommend we declare the results undefined.</p>
+
+<p><i>[See reflector message lib-6500 for further discussion.]</i></p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Change section 18.3/8 from:</p>
+<blockquote>
+ First, objects with static storage duration are destroyed and
+ functions registered by calling atexit are called. Objects with
+ static storage duration are destroyed in the reverse order of the
+ completion of their constructor. (Automatic objects are not
+ destroyed as a result of calling exit().) Functions registered with
+ atexit are called in the reverse order of their registration. A
+ function registered with atexit before an object obj1 of static
+ storage duration is initialized will not be called until obj1's
+ destruction has completed. A function registered with atexit after
+ an object obj2 of static storage duration is initialized will be
+ called before obj2's destruction starts.
+</blockquote>
+<p>to:</p>
+<blockquote>
+ First, objects with static storage duration are destroyed and
+ functions registered by calling atexit are called. Non-local objects
+ with static storage duration are destroyed in the reverse order of
+ the completion of their constructor. (Automatic objects are not
+ destroyed as a result of calling exit().) Functions registered with
+ atexit are called in the reverse order of their registration, except
+ that a function is called after any previously registered functions
+ that had already been called at the time it was registered. A
+ function registered with atexit before a non-local object obj1 of
+ static storage duration is initialized will not be called until
+ obj1's destruction has completed. A function registered with atexit
+ after a non-local object obj2 of static storage duration is
+ initialized will be called before obj2's destruction starts. A local
+ static object obj3 is destroyed at the same time it would be if a
+ function calling the obj3 destructor were registered with atexit at
+ the completion of the obj3 constructor.
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>See 99-0039/N1215, October 22, 1999, by Stephen D. Clamage for the analysis
+supporting to the proposed resolution.</p>
+<hr>
+<a name="5"><h3>5. String::compare specification questionable</h3></a><p>
+<b>Section:</b> 21.3.6.8 <a href="lib-strings.html#lib.string::compare"> [lib.string::compare]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Jack Reeves <b>Date:</b> 11 Dec 1997</p>
+<p>At the very end of the basic_string class definition is the signature: int
+compare(size_type pos1, size_type n1, const charT* s, size_type n2 = npos) const; In the
+following text this is defined as: returns
+basic_string<charT,traits,Allocator>(*this,pos1,n1).compare(
+basic_string<charT,traits,Allocator>(s,n2); </p>
+
+<p>Since the constructor basic_string(const charT* s, size_type n, const Allocator& a
+= Allocator()) clearly requires that s != NULL and n < npos and further states that it
+throws length_error if n == npos, it appears the compare() signature above should always
+throw length error if invoked like so: str.compare(1, str.size()-1, s); where 's' is some
+null terminated character array. </p>
+
+<p>This appears to be a typo since the obvious intent is to allow either the call above or
+something like: str.compare(1, str.size()-1, s, strlen(s)-1); </p>
+
+<p>This would imply that what was really intended was two signatures int compare(size_type
+pos1, size_type n1, const charT* s) const int compare(size_type pos1, size_type n1, const
+charT* s, size_type n2) const; each defined in terms of the corresponding constructor. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace the compare signature in 21.3
+(at the very end of the basic_string synopsis) which reads:</p>
+
+<blockquote>
+ <p><tt>int compare(size_type pos1, size_type n1,<br>
+ const charT* s,
+ size_type n2 = npos) const;</tt></p>
+</blockquote>
+
+<p>with:</p>
+
+<blockquote>
+ <p><tt>int compare(size_type pos1, size_type n1,<br>
+ const charT* s) const;<br>
+ int compare(size_type pos1, size_type n1,<br>
+ const charT* s,
+ size_type n2) const;</tt></p>
+</blockquote>
+
+<p>Replace the portion of 21.3.6.8
+paragraphs 5 and 6 which read:</p>
+
+<blockquote>
+ <p>
+<tt>int compare(size_type pos, size_type n1,<br>
+ charT * s, size_type n2
+ = npos) const;<br>
+ </tt>Returns:<tt><br>
+ basic_string<charT,traits,Allocator>(*this, pos, n1).compare(<br>
+
+ basic_string<charT,traits,Allocator>( s, n2))</tt>
+</p>
+</blockquote>
+
+<p>with:</p>
+
+<blockquote>
+ <p>
+<tt>int compare(size_type pos, size_type n1,<br>
+ const charT * s) const;<br>
+ </tt>Returns:<tt><br>
+ basic_string<charT,traits,Allocator>(*this, pos, n1).compare(<br>
+
+ basic_string<charT,traits,Allocator>( s ))<br>
+ <br>
+ int compare(size_type pos, size_type n1,<br>
+ const charT * s,
+ size_type n2) const;<br>
+ </tt>Returns:<tt><br>
+ basic_string<charT,traits,Allocator>(*this, pos, n1).compare(<br>
+
+ basic_string<charT,traits,Allocator>( s, n2))</tt>
+</p>
+</blockquote>
+
+<p>Editors please note that in addition to splitting the signature, the third argument
+becomes const, matching the existing synopsis.</p>
+<p><b>Rationale:</b></p>
+<p>While the LWG dislikes adding signatures, this is a clear defect in
+the Standard which must be fixed. The same problem was also
+identified in issues 7 (item 5) and 87.</p>
+<hr>
+<a name="7"><h3>7. String clause minor problems</h3></a><p>
+<b>Section:</b> 21 <a href="lib-strings.html#lib.strings"> [lib.strings]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 15 Dec 1997</p>
+<p>(1) In 21.3.5.4 , the description of template
+<class InputIterator> insert(iterator, InputIterator,
+InputIterator) makes no sense. It refers to a member function that
+doesn't exist. It also talks about the return value of a void
+function. </p>
+
+<p>(2) Several versions of basic_string::replace don't appear in the
+class synopsis. </p>
+
+<p>(3) basic_string::push_back appears in the synopsis, but is never
+described elsewhere. In the synopsis its argument is const charT,
+which doesn't makes much sense; it should probably be charT, or
+possible const charT&. </p>
+
+<p>(4) basic_string::pop_back is missing. </p>
+
+<p>(5) int compare(size_type pos, size_type n1, charT* s, size_type n2
+= npos) make no sense. First, it's const charT* in the synopsis and
+charT* in the description. Second, given what it says in RETURNS,
+leaving out the final argument will always result in an exception
+getting thrown. This is paragraphs 5 and 6 of
+21.3.6.8 </p>
+
+<p>(6) In table 37, in section 21.1.1 ,
+there's a note for X::move(s, p, n). It says "Copies correctly
+even where p is in [s, s+n)". This is correct as far as it goes,
+but it doesn't go far enough; it should also guarantee that the copy
+is correct even where s in in [p, p+n). These are two orthogonal
+guarantees, and neither one follows from the other. Both guarantees
+are necessary if X::move is supposed to have the same sort of
+semantics as memmove (which was clearly the intent), and both
+guarantees are necessary if X::move is actually supposed to be
+useful. </p>
+<p><b>Proposed resolution:</b></p>
+<p>ITEM 1: In 21.3.5.4 [lib.string::insert], change paragraph 16 to <br>
+<br>
+ EFFECTS: Equivalent to insert(p - begin(), basic_string(first, last)).<br>
+<br>
+ITEM 2: Not a defect; the Standard is clear.. There are ten versions of replace() in
+the synopsis, and ten versions in 21.3.5.6 [lib.string::replace].<br>
+<br>
+ITEM 3: Change the declaration of push_back in the string synopsis (21.3,
+[lib.basic.string]) from:</p>
+
+<p> void push_back(const charT)<br>
+<br>
+to<br>
+<br>
+ void push_back(charT)<br>
+<br>
+Add the following text immediately after 21.3.5.2 [lib.string::append], paragraph 10.<br>
+<br>
+ void basic_string::push_back(charT c);<br>
+ EFFECTS: Equivalent to append(static_cast<size_type>(1), c);<br>
+<br>
+ITEM 4: Not a defect. The omission appears to have been deliberate.<br>
+<br>
+ITEM 5: Duplicate; see issue 5 (and 87).<br>
+<br>
+ITEM 6: In table 37, Replace:<br>
+<br>
+ "Copies correctly even where p is in [s, s+n)."<br>
+<br>
+with:<br>
+<br>
+ "Copies correctly even where the ranges [p, p+n) and [s,
+s+n) overlap."</p>
+<hr>
+<a name="8"><h3>8. Locale::global lacks guarantee</h3></a><p>
+<b>Section:</b> 22.1.1.5 <a href="lib-locales.html#lib.locale.statics"> [lib.locale.statics]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 24 Dec 1997</p>
+<p>It appears there's an important guarantee missing from clause
+22. We're told that invoking locale::global(L) sets the C locale if L
+has a name. However, we're not told whether or not invoking
+setlocale(s) sets the global C++ locale. </p>
+
+<p>The intent, I think, is that it should not, but I can't find any
+such words anywhere. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add a sentence at the end of 22.1.1.5 ,
+paragraph 2: </p>
+
+<blockquote>
+ <p>No library function other than <tt>locale::global()</tt> shall affect
+ the value returned by <tt>locale()</tt>. </p>
+
+</blockquote>
+<hr>
+<a name="9"><h3>9. Operator new(0) calls should not yield the same pointer</h3></a><p>
+<b>Section:</b> 18.4.1 <a href="lib-support.html#lib.new.delete"> [lib.new.delete]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 4 Jan 1998</p>
+<p>Scott Meyers, in a comp.std.c++ posting: I just noticed that
+section 3.7.3.1 of CD2 seems to allow for the possibility that all
+calls to operator new(0) yield the same pointer, an implementation
+technique specifically prohibited by ARM 5.3.3.Was this prohibition
+really lifted? Does the FDIS agree with CD2 in the regard? [Issues
+list maintainer's note: the IS is the same.]</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the last paragraph of 3.7.3 from:</p>
+<blockquote>
+ <p>Any allocation and/or deallocation functions defined in a C++ program shall
+ conform to the semantics specified in 3.7.3.1 and 3.7.3.2.</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>Any allocation and/or deallocation functions defined in a C++ program,
+ including the default versions in the library, shall conform to the semantics
+ specified in 3.7.3.1 and 3.7.3.2.</p>
+</blockquote>
+<p>Change 3.7.3.1/2, next-to-last sentence, from :</p>
+<blockquote>
+ <p>If the size of the space requested is zero, the value returned shall not be
+ a null pointer value (4.10).</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>Even if the size of the space requested is zero, the request can fail. If
+ the request succeeds, the value returned shall be a non-null pointer value
+ (4.10) p0 different from any previously returned value p1, unless that value
+ p1 was since passed to an operator delete.</p>
+</blockquote>
+<p>5.3.4/7 currently reads:</p>
+<blockquote>
+ <p>When the value of the expression in a direct-new-declarator is zero, the
+ allocation function is called to allocate an array with no elements. The
+ pointer returned by the new-expression is non-null. [Note: If the library
+ allocation function is called, the pointer returned is distinct from the
+ pointer to any other object.]</p>
+</blockquote>
+<p>Retain the first sentence, and delete the remainder.</p>
+<p>18.4.1 currently has no text. Add the following:</p>
+<blockquote>
+ <p>Except where otherwise specified, the provisions of 3.7.3 apply to the
+ library versions of operator new and operator delete.</p>
+</blockquote>
+<p>To 18.4.1.3, add the following text:</p>
+<blockquote>
+ <p>The provisions of 3.7.3 do not apply to these reserved placement forms of
+ operator new and operator delete.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>See 99-0040/N1216, October 22, 1999, by Stephen D. Clamage for the analysis
+supporting to the proposed resolution.</p>
+<hr>
+<a name="11"><h3>11. Bitset minor problems</h3></a><p>
+<b>Section:</b> 23.3.5 <a href="lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 22 Jan 1998</p>
+<p>(1) bitset<>::operator[] is mentioned in the class synopsis (23.3.5), but it is
+not documented in 23.3.5.2. </p>
+
+<p>(2) The class synopsis only gives a single signature for bitset<>::operator[],
+reference operator[](size_t pos). This doesn't make much sense. It ought to be overloaded
+on const. reference operator[](size_t pos); bool operator[](size_t pos) const. </p>
+
+<p>(3) Bitset's stream input function (23.3.5.3) ought to skip all whitespace before
+trying to extract 0s and 1s. The standard doesn't explicitly say that, though. This should
+go in the Effects clause.</p>
+<p><b>Proposed resolution:</b></p>
+<p>ITEMS 1 AND 2:<br>
+<br>
+In the bitset synopsis (23.3.5 ),
+replace the member function <br>
+<br>
+<tt> reference operator[](size_t pos);<br>
+</tt><br>
+with the two member functions<br>
+<br>
+<tt> bool operator[](size_t pos) const; <br>
+ reference operator[](size_t pos); <br>
+</tt><br>
+Add the following text at the end of 23.3.5.2 ,
+immediately after paragraph 45:</p>
+
+<blockquote>
+ <p>
+<tt>bool operator[](size_t pos) const;</tt><br>
+ Requires: pos is valid<br>
+ Throws: nothing<br>
+ Returns: <tt>test(pos)</tt><br>
+ <br>
+ <tt>bitset<N>::reference operator[](size_t pos);</tt> <br>
+ Requires: pos is valid<br>
+ Throws: nothing<br>
+ Returns: An object of type <tt>bitset<N>::reference</tt> such that <tt>(*this)[pos]
+ == this->test(pos)</tt>, and such that <tt>(*this)[pos] = val</tt> is equivalent to <tt>this->set(pos,
+ val);</tt>
+</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The LWG believes Item 3 is not a defect. "Formatted
+input" implies the desired semantics. See 27.6.1.2 .
+</p>
+<hr>
+<a name="13"><h3>13. Eos refuses to die</h3></a><p>
+<b>Section:</b> 27.6.1.2.3 <a href="lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> William M. Miller <b>Date:</b> 3 Mar 1998</p>
+<p>In 27.6.1.2.3, there is a reference to "eos", which is
+the only one in the whole draft (at least using Acrobat search), so
+it's undefined. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.6.1.2.3 , replace "eos" with
+"charT()"</p>
+<hr>
+<a name="14"><h3>14. Locale::combine should be const</h3></a><p>
+<b>Section:</b> 22.1.1.3 <a href="lib-locales.html#lib.locale.members"> [lib.locale.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>locale::combine is the only member function of locale (other than constructors and
+destructor) that is not const. There is no reason for it not to be const, and good reasons
+why it should have been const. Furthermore, leaving it non-const conflicts with 22.1.1
+paragraph 6: "An instance of a locale is immutable." </p>
+
+<p>History: this member function originally was a constructor. it happened that the
+interface it specified had no corresponding language syntax, so it was changed to a member
+function. As constructors are never const, there was no "const" in the interface
+which was transformed into member "combine". It should have been added at that
+time, but the omission was not noticed. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.1.1 and also in 22.1.1.3 , add
+"const" to the declaration of member combine: </p>
+<blockquote>
+ <pre>template <class Facet> locale combine(const locale& other) const; </pre>
+</blockquote>
+<hr>
+<a name="15"><h3>15. Locale::name requirement inconsistent</h3></a><p>
+<b>Section:</b> 22.1.1.3 <a href="lib-locales.html#lib.locale.members"> [lib.locale.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>locale::name() is described as returning a string that can be passed to a locale
+constructor, but there is no matching constructor. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.1.1.3 , paragraph 5, replace
+"<tt>locale(name())</tt>" with
+"<tt>locale(name().c_str())</tt>".
+</p>
+<hr>
+<a name="16"><h3>16. Bad ctype_byname<char> decl</h3></a><p>
+<b>Section:</b> 22.2.1.4 <a href="lib-locales.html#lib.locale.ctype.byname.special"> [lib.locale.ctype.byname.special]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The new virtual members ctype_byname<char>::do_widen and do_narrow did not get
+edited in properly. Instead, the member do_widen appears four times, with wrong argument
+lists. </p>
+<p><b>Proposed resolution:</b></p>
+<p>The correct declarations for the overloaded members
+<tt>do_narrow</tt> and <tt>do_widen</tt> should be copied
+from 22.2.1.3 .</p>
+<hr>
+<a name="17"><h3>17. Bad bool parsing</h3></a><p>
+<b>Section:</b> 22.2.2.1.2 <a href="lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>This section describes the process of parsing a text boolean value from the input
+stream. It does not say it recognizes either of the sequences "true" or
+"false" and returns the corresponding bool value; instead, it says it recognizes
+only one of those sequences, and chooses which according to the received value of a
+reference argument intended for returning the result, and reports an error if the other
+sequence is found. (!) Furthermore, it claims to get the names from the ctype<>
+facet rather than the numpunct<> facet, and it examines the "boolalpha"
+flag wrongly; it doesn't define the value "loc"; and finally, it computes
+wrongly whether to use numeric or "alpha" parsing.<br>
+<br>
+I believe the correct algorithm is "as if": </p>
+
+<pre> // in, err, val, and str are arguments.
+ err = 0;
+ const numpunct<charT>& np = use_facet<numpunct<charT> >(str.getloc());
+ const string_type t = np.truename(), f = np.falsename();
+ bool tm = true, fm = true;
+ size_t pos = 0;
+ while (tm && pos < t.size() || fm && pos < f.size()) {
+ if (in == end) { err = str.eofbit; }
+ bool matched = false;
+ if (tm && pos < t.size()) {
+ if (!err && t[pos] == *in) matched = true;
+ else tm = false;
+ }
+ if (fm && pos < f.size()) {
+ if (!err && f[pos] == *in) matched = true;
+ else fm = false;
+ }
+ if (matched) { ++in; ++pos; }
+ if (pos > t.size()) tm = false;
+ if (pos > f.size()) fm = false;
+ }
+ if (tm == fm || pos == 0) { err |= str.failbit; }
+ else { val = tm; }
+ return in;</pre>
+
+<p>Notice this works reasonably when the candidate strings are both empty, or equal, or
+when one is a substring of the other. The proposed text below captures the logic of the
+code above.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.2.1.2 , in the first line of paragraph 14,
+change "&&" to "&".</p>
+
+<p>Then, replace paragraphs 15 and 16 as follows:</p>
+
+<blockquote>
+
+ <p>Otherwise target sequences are determined "as if" by
+ calling the members <tt>falsename()</tt> and
+ <tt>truename()</tt> of the facet obtained by
+ <tt>use_facet<numpunct<charT> >(str.getloc())</tt>.
+ Successive characters in the range <tt>[in,end)</tt> (see
+ [lib.sequence.reqmts]) are obtained and matched against
+ corresponding positions in the target sequences only as necessary to
+ identify a unique match. The input iterator <tt>in</tt> is
+ compared to <tt>end</tt> only when necessary to obtain a
+ character. If and only if a target sequence is uniquely matched,
+ <tt>val</tt> is set to the corresponding value.</p>
+
+</blockquote>
+
+<blockquote>
+ <p>The <tt>in</tt> iterator is always left pointing one position beyond the last character
+ successfully matched. If <tt>val</tt> is set, then err is set to <tt>str.goodbit</tt>; or to
+ <tt>str.eofbit</tt> if, when seeking another character to match, it is found that
+ <tt>(in==end)</tt>. If <tt>val</tt> is not set, then <i>err</i> is set to <tt>str.failbit</tt>; or to
+ <tt>(str.failbit|str.eofbit)</tt>if
+ the reason for the failure was that <tt>(in==end)</tt>. [Example: for targets
+ <tt>true</tt>:"a" and <tt>false</tt>:"abb", the input sequence "a" yields
+ <tt>val==true</tt> and <tt>err==str.eofbit</tt>; the input sequence "abc" yields
+ <tt>err=str.failbit</tt>, with <tt>in</tt> ending at the 'c' element. For targets
+ <tt>true</tt>:"1"
+ and <tt>false</tt>:"0", the input sequence "1" yields <tt>val==true</tt>
+ and <tt>err=str.goodbit</tt>. For empty targets (""), any input sequence yields
+ <tt>err==str.failbit</tt>. --end example]</p>
+</blockquote>
+<hr>
+<a name="18"><h3>18. Get(...bool&) omitted</h3></a><p>
+<b>Section:</b> 22.2.2.1.1 <a href="lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In the list of num_get<> non-virtual members on page 22-23, the member
+that parses bool values was omitted from the list of definitions of non-virtual
+members, though it is listed in the class definition and the corresponding
+virtual is listed everywhere appropriate. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add at the beginning of 22.2.2.1.1
+another get member for bool&, copied from the entry in
+22.2.2.1 .</p>
+<hr>
+<a name="19"><h3>19. "Noconv" definition too vague</h3></a><p>
+<b>Section:</b> 22.2.1.5.2 <a href="lib-locales.html#lib.locale.codecvt.virtuals"> [lib.locale.codecvt.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>
+In the definitions of codecvt<>::do_out and do_in, they are
+specified to return noconv if "no conversion is
+needed". This definition is too vague, and does not say
+normatively what is done with the buffers.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Change the entry for noconv in the table under paragraph 4 in section
+22.2.1.5.2 to read:
+</p>
+<blockquote>
+ <p>
+<tt>noconv</tt>: <tt>internT</tt> and <tt>externT</tt> are the same type,
+ and input sequence is identical to converted sequence.</p>
+</blockquote>
+<p>Change the Note in paragraph 2 to normative text as follows:</p>
+<blockquote>
+ <p>If returns <tt>noconv</tt>, <tt>internT</tt> and <tt>externT</tt> are the
+ same type and the converted sequence is identical to the input sequence <tt>[from,from_next)</tt>.
+ <tt>to_next</tt> is set equal to <tt>to</tt>, the value of <tt>state</tt> is
+ unchanged, and there are no changes to the values in <tt>[to, to_limit)</tt>.</p>
+</blockquote>
+<hr>
+<a name="20"><h3>20. Thousands_sep returns wrong type</h3></a><p>
+<b>Section:</b> 22.2.3.1.2 <a href="lib-locales.html#lib.facet.numpunct.virtuals"> [lib.facet.numpunct.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The synopsis for numpunct<>::do_thousands_sep, and the
+definition of numpunct<>::thousands_sep which calls it, specify
+that it returns a value of type char_type. Here it is erroneously
+described as returning a "string_type". </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.3.1.2 , above paragraph 2, change
+"string_type" to "char_type". </p>
+<hr>
+<a name="21"><h3>21. Codecvt_byname<> instantiations</h3></a><p>
+<b>Section:</b> 22.1.1.1.1 <a href="lib-locales.html#lib.locale.category"> [lib.locale.category]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In the second table in the section, captioned "Required
+instantiations", the instantiations for codecvt_byname<>
+have been omitted. These are necessary to allow users to construct a
+locale by name from facets. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add in 22.1.1.1.1 to the table captioned
+"Required instantiations", in the category "ctype"
+the lines </p>
+
+<blockquote>
+ <pre>codecvt_byname<char,char,mbstate_t>,
+codecvt_byname<wchar_t,char,mbstate_t> </pre>
+</blockquote>
+<hr>
+<a name="22"><h3>22. Member open vs. flags</h3></a><p>
+<b>Section:</b> 27.8.1.7 <a href="lib-iostreams.html#lib.ifstream.members"> [lib.ifstream.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The description of basic_istream<>::open leaves unanswered questions about how it
+responds to or changes flags in the error status for the stream. A strict reading
+indicates that it ignores the bits and does not change them, which confuses users who do
+not expect eofbit and failbit to remain set after a successful open. There are three
+reasonable resolutions: 1) status quo 2) fail if fail(), ignore eofbit 3) clear failbit
+and eofbit on call to open(). </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.8.1.7 paragraph 3, <i>and</i> in 27.8.1.10 paragraph 3, under open() effects, add a footnote:
+</p>
+
+<blockquote>
+ <p>A successful open does not change the error state.</p>
+</blockquote>
+<hr>
+<a name="24"><h3>24. "do_convert" doesn't exist</h3></a><p>
+<b>Section:</b> 22.2.1.5.2 <a href="lib-locales.html#lib.locale.codecvt.virtuals"> [lib.locale.codecvt.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The description of codecvt<>::do_out and do_in mentions a
+symbol "do_convert" which is not defined in the
+standard. This is a leftover from an edit, and should be "do_in
+and do_out". </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.1.5 , paragraph 3, change
+"do_convert" to "do_in or do_out". Also, in 22.2.1.5.2 , change "do_convert()" to "do_in
+or do_out". </p>
+<hr>
+<a name="25"><h3>25. String operator<< uses width() value wrong</h3></a><p>
+<b>Section:</b> 21.3.7.9 <a href="lib-strings.html#lib.string.io"> [lib.string.io]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In the description of operator<< applied to strings, the standard says that uses
+the smaller of os.width() and str.size(), to pad "as described in stage 3"
+elsewhere; but this is inconsistent, as this allows no possibility of space for padding. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 21.3.7.9 paragraph 4 from:<br>
+<br>
+ "... where <tt>n</tt> is the smaller of <tt>os.width()</tt> and <tt>str.size()</tt>;
+..."<br>
+<br>
+to: <br>
+<br>
+ "... where <tt>n</tt> is the larger of <tt>os.width()</tt> and <tt>str.size()</tt>;
+..."</p>
+<hr>
+<a name="26"><h3>26. Bad sentry example</h3></a><p>
+<b>Section:</b> 27.6.1.1.2 <a href="lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In paragraph 6, the code in the example: </p>
+
+<pre> template <class charT, class traits = char_traits<charT> >
+ basic_istream<charT,traits>::sentry(
+ basic_istream<charT,traits>& is, bool noskipws = false) {
+ ...
+ int_type c;
+ typedef ctype<charT> ctype_type;
+ const ctype_type& ctype = use_facet<ctype_type>(is.getloc());
+ while ((c = is.rdbuf()->snextc()) != traits::eof()) {
+ if (ctype.is(ctype.space,c)==0) {
+ is.rdbuf()->sputbackc (c);
+ break;
+ }
+ }
+ ...
+ }</pre>
+
+<p>fails to demonstrate correct use of the facilities described. In
+particular, it fails to use traits operators, and specifies incorrect
+semantics. (E.g. it specifies skipping over the first character in the
+sequence without examining it.) </p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove the example above from 27.6.1.1.2
+paragraph 6.</p>
+<p><b>Rationale:</b></p>
+<p>The originally proposed replacement code for the example was not
+correct. The LWG tried in Kona and again in Tokyo to correct it
+without success. In Tokyo, an implementor reported that actual working
+code ran over one page in length and was quite complicated. The LWG
+decided that it would be counter-productive to include such a lengthy
+example, which might well still contain errors.</p>
+<hr>
+<a name="27"><h3>27. String::erase(range) yields wrong iterator</h3></a><p>
+<b>Section:</b> 21.3.5.5 <a href="lib-strings.html#lib.string::erase"> [lib.string::erase]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The string::erase(iterator first, iterator last) is specified to return an element one
+place beyond the next element after the last one erased. E.g. for the string
+"abcde", erasing the range ['b'..'d') would yield an iterator for element 'e',
+while 'd' has not been erased. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 21.3.5.5 , paragraph 10, change: </p>
+
+<blockquote>
+ <p>Returns: an iterator which points to the element immediately following _last_ prior to
+ the element being erased. </p>
+</blockquote>
+
+<p>to read </p>
+
+<blockquote>
+ <p>Returns: an iterator which points to the element pointed to by _last_ prior to the
+ other elements being erased. </p>
+</blockquote>
+<hr>
+<a name="28"><h3>28. Ctype<char>is ambiguous</h3></a><p>
+<b>Section:</b> 22.2.1.3.2 <a href="lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The description of the vector form of ctype<char>::is can be interpreted to mean
+something very different from what was intended. Paragraph 4 says </p>
+
+<blockquote>
+ <p>Effects: The second form, for all *p in the range [low, high), assigns vec[p-low] to
+ table()[(unsigned char)*p]. </p>
+</blockquote>
+
+<p>This is intended to copy the value indexed from table()[] into the place identified in
+vec[]. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 22.2.1.3.2 , paragraph 4, to read </p>
+
+<blockquote>
+ <p>Effects: The second form, for all *p in the range [low, high), assigns into vec[p-low]
+ the value table()[(unsigned char)*p]. </p>
+</blockquote>
+<hr>
+<a name="29"><h3>29. Ios_base::init doesn't exist</h3></a><p>
+<b>Section:</b> 27.3.1 <a href="lib-iostreams.html#lib.narrow.stream.objects"> [lib.narrow.stream.objects]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>Sections 27.3.1 and 27.3.2 mention
+a function ios_base::init, which is not defined. Probably they mean
+basic_ios<>::init, defined in 27.4.4.1 ,
+paragraph 3. </p>
+<p><b>Proposed resolution:</b></p>
+<p>[R12: modified to include paragraph 5.]</p>
+
+<p>In 27.3.1 paragraph 2 and 5, change </p>
+
+<blockquote>
+ <p>ios_base::init </p>
+</blockquote>
+
+<p>to </p>
+
+<blockquote>
+ <p>basic_ios<char>::init </p>
+</blockquote>
+
+<p>Also, make a similar change in 27.3.2 except it
+should read </p>
+
+<blockquote>
+ <p>basic_ios<wchar_t>::init </p>
+</blockquote>
+<hr>
+<a name="30"><h3>30. Wrong header for LC_*</h3></a><p>
+<b>Section:</b> 22.1.1.1.1 <a href="lib-locales.html#lib.locale.category"> [lib.locale.category]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>Paragraph 2 implies that the C macros LC_CTYPE etc. are defined in <cctype>,
+where they are in fact defined elsewhere to appear in <clocale>. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.1.1.1.1 , paragraph 2, change
+"<cctype>" to read "<clocale>". </p>
+<hr>
+<a name="31"><h3>31. Immutable locale values</h3></a><p>
+<b>Section:</b> 22.1.1 <a href="lib-locales.html#lib.locale"> [lib.locale]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>Paragraph 6, says "An instance of <tt>locale</tt> is
+<i>immutable</i>; once a facet reference is obtained from it,
+...". This has caused some confusion, because locale variables
+are manifestly assignable. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.1.1 replace paragraph 6</p>
+
+<blockquote>
+ <p>An instance of <tt>locale</tt> is immutable; once a facet
+ reference is obtained from it, that reference remains usable as long
+ as the locale value itself exists.</p>
+</blockquote>
+
+<p>with</p>
+
+<blockquote>
+ <p>Once a facet reference is obtained from a locale object by
+ calling use_facet<>, that reference remains usable, and the
+ results from member functions of it may be cached and re-used, as
+ long as some locale object refers to that facet.</p>
+</blockquote>
+<hr>
+<a name="32"><h3>32. Pbackfail description inconsistent</h3></a><p>
+<b>Section:</b> 27.5.2.4.4 <a href="lib-iostreams.html#lib.streambuf.virt.pback"> [lib.streambuf.virt.pback]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The description of the required state before calling virtual member
+basic_streambuf<>::pbackfail requirements is inconsistent with the conditions
+described in 27.5.2.2.4 [lib.streambuf.pub.pback] where member sputbackc calls it.
+Specifically, the latter says it calls pbackfail if: </p>
+
+<p> traits::eq(c,gptr()[-1]) is false </p>
+
+<p>where pbackfail claims to require: </p>
+
+<p> traits::eq(*gptr(),traits::to_char_type(c)) returns false </p>
+
+<p>It appears that the pbackfail description is wrong. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.5.2.4.4 , paragraph 1, change:</p>
+
+<blockquote>
+ <p>"<tt>traits::eq(*gptr(),traits::to_char_type( c))</tt>"</p>
+</blockquote>
+
+<p>to </p>
+
+<blockquote>
+ <p>"<tt>traits::eq(traits::to_char_type(c),gptr()[-1])</tt>"
+ </p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Note deliberate reordering of arguments for clarity in addition to the correction of
+the argument value.</p>
+<hr>
+<a name="33"><h3>33. Codecvt<> mentions from_type</h3></a><p>
+<b>Section:</b> 22.2.1.5.2 <a href="lib-locales.html#lib.locale.codecvt.virtuals"> [lib.locale.codecvt.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In the table defining the results from do_out and do_in, the specification for the
+result <i>error</i> says </p>
+
+<blockquote>
+ <p>encountered a from_type character it could not convert </p>
+</blockquote>
+
+<p>but from_type is not defined. This clearly is intended to be an externT for do_in, or
+an internT for do_out. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.1.5.2 paragraph 4, replace the definition
+in the table for the case of _error_ with </p>
+
+<blockquote>
+ <p>encountered a character in <tt>[from,from_end)</tt> that it could not convert. </p>
+</blockquote>
+<hr>
+<a name="34"><h3>34. True/falsename() not in ctype<></h3></a><p>
+<b>Section:</b> 22.2.2.2.2 <a href="lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In paragraph 19, Effects:, members truename() and falsename are used from facet
+ctype<charT>, but it has no such members. Note that this is also a problem in
+22.2.2.1.2, addressed in (4). </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.2.2.2 , paragraph 19, in the Effects:
+clause for member put(...., bool), replace the initialization of the
+string_type value s as follows: </p>
+
+<blockquote>
+ <pre>const numpunct& np = use_facet<numpunct<charT> >(loc);
+string_type s = val ? np.truename() : np.falsename(); </pre>
+</blockquote>
+<hr>
+<a name="35"><h3>35. No manipulator unitbuf in synopsis</h3></a><p>
+<b>Section:</b> 27.4 <a href="lib-iostreams.html#lib.iostreams.base"> [lib.iostreams.base]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In 27.4.5.1 , we have a definition for a manipulator
+named "unitbuf". Unlike other manipulators, it's not listed
+in synopsis. Similarly for "nounitbuf". </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add to the synopsis for <ios> in 27.4 , after
+the entry for "nouppercase", the prototypes: </p>
+
+<blockquote>
+ <pre>ios_base& unitbuf(ios_base& str);
+ios_base& nounitbuf(ios_base& str); </pre>
+</blockquote>
+<hr>
+<a name="36"><h3>36. Iword & pword storage lifetime omitted</h3></a><p>
+<b>Section:</b> 27.4.2.5 <a href="lib-iostreams.html#lib.ios.base.storage"> [lib.ios.base.storage]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In the definitions for ios_base::iword and pword, the lifetime of the storage is
+specified badly, so that an implementation which only keeps the last value stored appears
+to conform. In particular, it says: </p>
+
+<p>The reference returned may become invalid after another call to the object's iword
+member with a different index ... </p>
+
+<p>This is not idle speculation; at least one implementation was done this way. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add in 27.4.2.5 , in both paragraph 2 and also in
+paragraph 4, replace the sentence: </p>
+
+<blockquote>
+ <p>The reference returned may become invalid after another call to the object's iword
+ [pword] member with a different index, after a call to its copyfmt member, or when the
+ object is destroyed. </p>
+</blockquote>
+
+<p>with: </p>
+
+<blockquote>
+ <p>The reference returned is invalid after any other operations on the object. However,
+ the value of the storage referred to is retained, so that until the next call to copyfmt,
+ calling iword [pword] with the same index yields another reference to the same value. </p>
+</blockquote>
+
+<p>substituting "iword" or "pword" as appropriate. </p>
+<hr>
+<a name="37"><h3>37. Leftover "global" reference</h3></a><p>
+<b>Section:</b> 22.1.1 <a href="lib-locales.html#lib.locale"> [lib.locale]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>In the overview of locale semantics, paragraph 4, is the sentence </p>
+
+<blockquote>
+ <p>If Facet is not present in a locale (or, failing that, in the global locale), it throws
+ the standard exception bad_cast. </p>
+</blockquote>
+
+<p>This is not supported by the definition of use_facet<>, and represents semantics
+from an old draft. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.1.1 , paragraph 4, delete the parenthesized
+expression </p>
+
+<blockquote>
+ <p>(or, failing that, in the global locale) </p>
+</blockquote>
+<hr>
+<a name="38"><h3>38. Facet definition incomplete</h3></a><p>
+<b>Section:</b> 22.1.2 <a href="lib-locales.html#lib.locale.global.templates"> [lib.locale.global.templates]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>It has been noticed by Esa Pulkkinen that the definition of
+"facet" is incomplete. In particular, a class derived from
+another facet, but which does not define a member <i>id</i>, cannot
+safely serve as the argument <i>F</i> to use_facet<F>(loc),
+because there is no guarantee that a reference to the facet instance
+stored in <i>loc</i> is safely convertible to <i>F</i>. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In the definition of std::use_facet<>(), replace the text in paragraph 1 which
+reads: </p>
+
+<blockquote>
+ <p>Get a reference to a facet of a locale. </p>
+</blockquote>
+
+<p>with: </p>
+
+<blockquote>
+ <p>Requires: <tt>Facet</tt> is a facet class whose definition
+ contains the public static member <tt>id</tt> as defined in 22.1.1.1.2 . </p>
+</blockquote>
+
+<p><i>[
+Kona: strike as overspecification the text "(not inherits)"
+from the original resolution, which read "... whose definition
+contains (not inherits) the public static member
+<tt>id</tt>..."
+]</i></p>
+
+<hr>
+<a name="39"><h3>39. istreambuf_iterator<>::operator++(int) definition garbled</h3></a><p>
+<b>Section:</b> 24.5.3.4 <a href="lib-iterators.html#lib.istreambuf.iterator::op++"> [lib.istreambuf.iterator::op++]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>Following the definition of istreambuf_iterator<>::operator++(int) in paragraph
+3, the standard contains three lines of garbage text left over from a previous edit. </p>
+
+<blockquote>
+ <pre>istreambuf_iterator<charT,traits> tmp = *this;
+sbuf_->sbumpc();
+return(tmp); </pre>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>In 24.5.3.4 , delete the three lines of code at the
+end of paragraph 3. </p>
+<hr>
+<a name="40"><h3>40. Meaningless normative paragraph in examples</h3></a><p>
+<b>Section:</b> 22.2.8 <a href="lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>Paragraph 3 of the locale examples is a description of part of an
+implementation technique that has lost its referent, and doesn't mean
+anything. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Delete 22.2.8 paragraph 3 which begins "This
+initialization/identification system depends...", or (at the
+editor's option) replace it with a place-holder to keep the paragraph
+numbering the same. </p>
+<hr>
+<a name="41"><h3>41. Ios_base needs clear(), exceptions()</h3></a><p>
+<b>Section:</b> 27.4.2 <a href="lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The description of ios_base::iword() and pword() in 27.4.2.4 , say that if they fail, they "set badbit,
+which may throw an exception". However, ios_base offers no
+interface to set or to test badbit; those interfaces are defined in
+basic_ios<>. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the description in 27.4.2.5 in
+paragraph 2, and also in paragraph 4, as follows. Replace</p>
+
+<blockquote>
+ <p>If the function fails it sets badbit, which may throw an exception.</p>
+</blockquote>
+
+<p>with</p>
+
+<blockquote>
+ <p>If the function fails, and <tt>*this</tt> is a base sub-object of
+ a <tt>basic_ios<></tt> object or sub-object, the effect is
+ equivalent to calling <tt>basic_ios<>::setstate(badbit)</tt>
+ on the derived object (which may throw <tt>failure</tt>).</p>
+</blockquote>
+
+<p><i>[Kona: LWG reviewed wording; setstate(failbit) changed to
+setstate(badbit).]</i></p>
+
+<hr>
+<a name="42"><h3>42. String ctors specify wrong default allocator</h3></a><p>
+<b>Section:</b> 21.3 <a href="lib-strings.html#lib.basic.string"> [lib.basic.string]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 6 Aug 1998</p>
+<p>The basic_string<> copy constructor: </p>
+
+<pre>basic_string(const basic_string& str, size_type pos = 0,
+ size_type n = npos, const Allocator& a = Allocator()); </pre>
+
+<p>specifies an Allocator argument default value that is
+counter-intuitive. The natural choice for a the allocator to copy from
+is str.get_allocator(). Though this cannot be expressed in
+default-argument notation, overloading suffices. </p>
+
+<p>Alternatively, the other containers in Clause 23 (deque, list,
+vector) do not have this form of constructor, so it is inconsistent,
+and an evident source of confusion, for basic_string<> to have
+it, so it might better be removed. </p>
+<p><b>Proposed resolution:</b></p>
+<p> In 21.3 , replace the declaration of the copy
+constructor as follows: </p>
+
+<blockquote>
+ <pre>basic_string(const basic_string& str);
+basic_string(const basic_string& str, size_type pos, size_type n = npos,
+ const Allocator& a = Allocator());</pre>
+</blockquote>
+
+<p>In 21.3.1 , replace the copy constructor declaration
+as above. Add to paragraph 5, Effects:</p>
+
+<blockquote>
+ <p>In the first form, the Allocator value used is copied from
+ <tt>str.get_allocator()</tt>.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The LWG believes the constructor is actually broken, rather than
+just an unfortunate design choice.</p>
+
+<p>The LWG considered two other possible resolutions:</p>
+
+<p>A. In 21.3 , replace the declaration of the copy
+constructor as follows:</p>
+
+<blockquote>
+ <pre>basic_string(const basic_string& str, size_type pos = 0,
+ size_type n = npos);
+basic_string(const basic_string& str, size_type pos,
+ size_type n, const Allocator& a); </pre>
+</blockquote>
+
+<p>In 21.3.1 , replace the copy constructor declaration
+as above. Add to paragraph 5, Effects: </p>
+
+<blockquote>
+ <p>When no <tt>Allocator</tt> argument is provided, the string is constructed using the
+ value <tt>str.get_allocator()</tt>. </p>
+</blockquote>
+
+<p>B. In 21.3 , and also in 21.3.1 , replace
+the declaration of the copy constructor as follows: </p>
+
+<blockquote>
+ <pre>basic_string(const basic_string& str, size_type pos = 0,
+ size_type n = npos); </pre>
+</blockquote>
+
+<p>The proposed resolution reflects the original intent of the LWG. It
+was also noted by Pete Becker that this fix "will cause
+a small amount of existing code to now work correctly."</p>
+
+<p><i>[
+Kona: issue editing snafu fixed - the proposed resolution now correctly
+reflects the LWG consensus.
+]</i></p>
+<hr>
+<a name="46"><h3>46. Minor Annex D errors</h3></a><p>
+<b>Section:</b> D.7 <a href="future.html#depr.str.strstreams"> [depr.str.strstreams]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Brendan Kehoe <b>Date:</b> 1 Jun 1998</p>
+<p>See lib-6522 and edit-814.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change D.7.1 (since streambuf is a typedef of
+basic_streambuf<char>) from:</p>
+
+<pre> virtual streambuf<char>* setbuf(char* s, streamsize n);</pre>
+
+<p>to:</p>
+
+<pre> virtual streambuf* setbuf(char* s, streamsize n);</pre>
+
+<p>In D.7.4 insert the semicolon now missing after
+int_type:</p>
+
+<pre> namespace std {
+ class strstream
+ : public basic_iostream<char> {
+ public:
+ // Types
+ typedef char char_type;
+ typedef typename char_traits<char>::int_type int_type
+ typedef typename char_traits<char>::pos_type pos_type;</pre>
+<hr>
+<a name="47"><h3>47. Imbue() and getloc() Returns clauses swapped</h3></a><p>
+<b>Section:</b> 27.4.2.3 <a href="lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 21 Jun 1998</p>
+<p>Section 27.4.2.3 specifies how imbue() and getloc() work. That
+section has two RETURNS clauses, and they make no sense as
+stated. They make perfect sense, though, if you swap them. Am I
+correct in thinking that paragraphs 2 and 4 just got mixed up by
+accident?</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.4.2.3 swap paragraphs 2 and 4.</p>
+<hr>
+<a name="48"><h3>48. Use of non-existent exception constructor</h3></a><p>
+<b>Section:</b> 27.4.2.1.1 <a href="lib-iostreams.html#lib.ios::failure"> [lib.ios::failure]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 21 Jun 1998</p>
+<p>27.4.2.1.1, paragraph 2, says that class failure initializes the
+base class, exception, with exception(msg). Class exception (see
+18.6.1) has no such constructor.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace 27.4.2.1.1 , paragraph 2, with</p>
+
+<blockquote>
+ <p>EFFECTS: Constructs an object of class <tt>failure</tt>.</p>
+</blockquote>
+<hr>
+<a name="50"><h3>50. Copy constructor and assignment operator of ios_base</h3></a><p>
+<b>Section:</b> 27.4.2 <a href="lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 21 Jun 1998</p>
+<p>As written, ios_base has a copy constructor and an assignment
+operator. (Nothing in the standard says it doesn't have one, and all
+classes have copy constructors and assignment operators unless you
+take specific steps to avoid them.) However, nothing in 27.4.2 says
+what the copy constructor and assignment operator do. </p>
+
+<p>My guess is that this was an oversight, that ios_base is, like
+basic_ios, not supposed to have a copy constructor or an assignment
+operator.</p>
+
+<p>
+Jerry Schwarz comments: Yes, its an oversight, but in the opposite
+sense to what you're suggesting. At one point there was a definite
+intention that you could copy ios_base. It's an easy way to save the
+entire state of a stream for future use. As you note, to carry out
+that intention would have required a explicit description of the
+semantics (e.g. what happens to the iarray and parray stuff).
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.4.2 , class ios_base, specify the copy
+constructor and operator= members as being private.</p>
+<p><b>Rationale:</b></p>
+<p>The LWG believes the difficulty of specifying correct semantics
+outweighs any benefit of allowing ios_base objects to be copyable.</p>
+<hr>
+<a name="51"><h3>51. Requirement to not invalidate iterators missing</h3></a><p>
+<b>Section:</b> 23.1 <a href="lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> David Vandevoorde <b>Date:</b> 23 Jun 1998</p>
+<p>The std::sort algorithm can in general only sort a given sequence
+by moving around values. The list<>::sort() member on the other
+hand could move around values or just update internal pointers. Either
+method can leave iterators into the list<> dereferencable, but
+they would point to different things. </p>
+
+<p>Does the FDIS mandate anywhere which method should be used for
+list<>::sort()?</p>
+
+<p>Matt Austern comments:</p>
+
+<p>I think you've found an omission in the standard. </p>
+
+<p>The library working group discussed this point, and there was
+supposed to be a general requirement saying that list, set, map,
+multiset, and multimap may not invalidate iterators, or change the
+values that iterators point to, except when an operation does it
+explicitly. So, for example, insert() doesn't invalidate any iterators
+and erase() and remove() only invalidate iterators pointing to the
+elements that are being erased. </p>
+
+<p>I looked for that general requirement in the FDIS, and, while I
+found a limited form of it for the sorted associative containers, I
+didn't find it for list. It looks like it just got omitted. </p>
+
+<p>The intention, though, is that list<>::sort does not
+invalidate any iterators and does not change the values that any
+iterator points to. There would be no reason to have the member
+function otherwise.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add a new paragraph at the end of 23.1:</p>
+
+<blockquote>
+ <p>Unless otherwise specified (either explicitly or by defining a function in terms of
+ other functions), invoking a container member function or passing a container as an
+ argument to a library function shall not invalidate iterators to, or change the values of,
+ objects within that container. </p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>This was US issue CD2-23-011; it was accepted in London but the
+change was not made due to an editing oversight. The wording in the
+proposed resolution below is somewhat updated from CD2-23-011,
+particularly the addition of the phrase "or change the values
+of"</p>
+<hr>
+<a name="52"><h3>52. Small I/O problems</h3></a><p>
+<b>Section:</b> 27.4.3.2 <a href="lib-iostreams.html#lib.fpos.operations"> [lib.fpos.operations]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 23 Jun 1998</p>
+<p>First, 27.4.4.1 , table 89. This is pretty obvious:
+it should be titled "basic_ios<>() effects", not
+"ios_base() effects". </p>
+
+<p>[The second item is a duplicate; see issue <a href="lwg-closed.html#6">6</a> for
+resolution.]</p>
+
+<p>Second, 27.4.3.2 table 88 . There are a couple
+different things wrong with it, some of which I've already discussed
+with Jerry, but the most obvious mechanical sort of error is that it
+uses expressions like P(i) and p(i), without ever defining what sort
+of thing "i" is.
+</p>
+
+<p>(The other problem is that it requires support for streampos
+arithmetic. This is impossible on some systems, i.e. ones where file
+position is a complicated structure rather than just a number. Jerry
+tells me that the intention was to require syntactic support for
+streampos arithmetic, but that it wasn't actually supposed to do
+anything meaningful except on platforms, like Unix, where genuine
+arithmetic is possible.) </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.4.4.1 table 89 title from
+"ios_base() effects" to "basic_ios<>()
+effects". </p>
+<hr>
+<a name="53"><h3>53. Basic_ios destructor unspecified</h3></a><p>
+<b>Section:</b> 27.4.4.1 <a href="lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 23 Jun 1998</p>
+<p>There's nothing in 27.4.4 saying what basic_ios's destructor does.
+The important question is whether basic_ios::~basic_ios() destroys
+rdbuf().</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add after 27.4.4.1 paragraph 2:</p>
+
+<blockquote>
+ <p><tt>virtual ~basic_ios();</tt></p>
+ <p>
+<b>Notes</b>: The destructor does not destroy <tt>rdbuf()</tt>.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The LWG reviewed the additional question of whether or not
+<tt>rdbuf(0)</tt> may set <tt>badbit</tt>. The answer is
+clearly yes; it may be set via <tt>clear()</tt>. See 27.4.4.2 , paragraph 6. This issue was reviewed at length
+by the LWG, which removed from the original proposed resolution a
+footnote which incorrectly said "<tt>rdbuf(0)</tt> does not set
+<tt>badbit</tt>".</p>
+<hr>
+<a name="54"><h3>54. Basic_streambuf's destructor</h3></a><p>
+<b>Section:</b> 27.5.2.1 <a href="lib-iostreams.html#lib.streambuf.cons"> [lib.streambuf.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 25 Jun 1998</p>
+<p>The class synopsis for basic_streambuf shows a (virtual)
+destructor, but the standard doesn't say what that destructor does. My
+assumption is that it does nothing, but the standard should say so
+explicitly. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Add after 27.5.2.1 paragraph 2:</p>
+
+<blockquote>
+ <p><tt>virtual ~basic_streambuf();</tt></p>
+ <p>
+<b>Effects</b>: None.</p>
+</blockquote>
+<hr>
+<a name="55"><h3>55. Invalid stream position is undefined</h3></a><p>
+<b>Section:</b> 27 <a href="lib-iostreams.html#lib.input.output"> [lib.input.output]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 26 Jun 1998</p>
+<p>Several member functions in clause 27 are defined in certain
+circumstances to return an "invalid stream position", a term
+that is defined nowhere in the standard. Two places (27.5.2.4.2,
+paragraph 4, and 27.8.1.4, paragraph 15) contain a cross-reference to
+a definition in _lib.iostreams.definitions_, a nonexistent
+section. </p>
+
+<p>I suspect that the invalid stream position is just supposed to be
+pos_type(-1). Probably best to say explicitly in (for example)
+27.5.2.4.2 that the return value is pos_type(-1), rather than to use
+the term "invalid stream position", define that term
+somewhere, and then put in a cross-reference. </p>
+
+<p>The phrase "invalid stream position" appears ten times in
+the C++ Standard. In seven places it refers to a return value, and it
+should be changed. In three places it refers to an argument, and it
+should not be changed. Here are the three places where "invalid
+stream position" should not be changed:</p>
+
+<blockquote>
+ <p>27.7.1.3 , paragraph 14<br>
+ 27.8.1.4 , paragraph 14<br>
+ D.7.1.3 , paragraph 17
+ <a href="lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>
+</p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.5.2.4.2 , paragraph 4, change "Returns an
+object of class pos_type that stores an invalid stream position
+(_lib.iostreams.definitions_)" to "Returns
+<tt>pos_type(off_type(-1))</tt>".
+</p>
+
+<p>In 27.5.2.4.2 , paragraph 6, change "Returns
+an object of class pos_type that stores an invalid stream
+position" to "Returns <tt>pos_type(off_type(-1))</tt>".</p>
+
+<p>In 27.7.1.3 , paragraph 13, change "the object
+stores an invalid stream position" to "the return value is
+<tt>pos_type(off_type(-1))</tt>". </p>
+
+<p>In 27.8.1.4 , paragraph 13, change "returns an
+invalid stream position (27.4.3)" to "returns
+<tt>pos_type(off_type(-1))</tt>" </p>
+
+<p>In 27.8.1.4 , paragraph 15, change "Otherwise
+returns an invalid stream position (_lib.iostreams.definitions_)"
+to "Otherwise returns <tt>pos_type(off_type(-1))</tt>"
+</p>
+
+<p>In D.7.1.3 , paragraph 15, change "the object
+stores an invalid stream position" to "the return value is
+<tt>pos_type(off_type(-1))</tt>" </p>
+
+<p>In D.7.1.3 , paragraph 18, change "the object
+stores an invalid stream position" to "the return value is
+<tt>pos_type(off_type(-1))</tt>"</p>
+<hr>
+<a name="56"><h3>56. Showmanyc's return type</h3></a><p>
+<b>Section:</b> 27.5.2 <a href="lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 29 Jun 1998</p>
+<p>The class summary for basic_streambuf<>, in 27.5.2, says that
+showmanyc has return type int. However, 27.5.2.4.3 says that its
+return type is streamsize. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change <tt>showmanyc</tt>'s return type in the
+27.5.2 class summary to <tt>streamsize</tt>.</p>
+<hr>
+<a name="57"><h3>57. Mistake in char_traits</h3></a><p>
+<b>Section:</b> 21.1.3.2 <a href="lib-strings.html#lib.char.traits.specializations.wchar.t"> [lib.char.traits.specializations.wchar.t]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 1 Jul 1998</p>
+<p>21.1.3.2, paragraph 3, says "The types streampos and
+wstreampos may be different if the implementation supports no shift
+encoding in narrow-oriented iostreams but supports one or more shift
+encodings in wide-oriented streams". </p>
+
+<p>That's wrong: the two are the same type. The <iosfwd> summary
+in 27.2 says that streampos and wstreampos are, respectively, synonyms
+for fpos<char_traits<char>::state_type> and
+fpos<char_traits<wchar_t>::state_type>, and, flipping back
+to clause 21, we see in 21.1.3.1 and 21.1.3.2 that
+char_traits<char>::state_type and
+char_traits<wchar_t>::state_type must both be mbstate_t. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove the sentence in 21.1.3.2 paragraph 3 which
+begins "The types streampos and wstreampos may be
+different..." . </p>
+<hr>
+<a name="59"><h3>59. Ambiguity in specification of gbump</h3></a><p>
+<b>Section:</b> 27.5.2.3.1 <a href="lib-iostreams.html#lib.streambuf.get.area"> [lib.streambuf.get.area]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 28 Jul 1998</p>
+<p>27.5.2.3.1 says that basic_streambuf::gbump() "Advances the
+next pointer for the input sequence by n." </p>
+
+<p>The straightforward interpretation is that it is just gptr() +=
+n. An alternative interpretation, though, is that it behaves as if it
+calls sbumpc n times. (The issue, of course, is whether it might ever
+call underflow.) There is a similar ambiguity in the case of
+pbump. </p>
+
+<p>(The "classic" AT&T implementation used the
+former interpretation.)</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.5.2.3.1 paragraph 4 gbump effects from:</p>
+
+<blockquote>
+ <p>Effects: Advances the next pointer for the input sequence by n.</p>
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+ <p>Effects: Adds <tt>n</tt> to the next pointer for the input sequence.</p>
+</blockquote>
+
+<p>Make the same change to 27.5.2.3.2 paragraph 4 pbump
+effects.</p>
+<hr>
+<a name="60"><h3>60. What is a formatted input function?</h3></a><p>
+<b>Section:</b> 27.6.1.2.1 <a href="lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 3 Aug 1998</p>
+<p>Paragraph 1 of 27.6.1.2.1 contains general requirements for all
+formatted input functions. Some of the functions defined in section
+27.6.1.2 explicitly say that those requirements apply ("Behaves
+like a formatted input member (as described in 27.6.1.2.1)"), but
+others don't. The question: is 27.6.1.2.1 supposed to apply to
+everything in 27.6.1.2, or only to those member functions that
+explicitly say "behaves like a formatted input member"? Or
+to put it differently: are we to assume that everything that appears
+in a section called "Formatted input functions" really is a
+formatted input function? I assume that 27.6.1.2.1 is intended to
+apply to the arithmetic extractors (27.6.1.2.2), but I assume that it
+is not intended to apply to extractors like </p>
+
+<pre> basic_istream& operator>>(basic_istream& (*pf)(basic_istream&));</pre>
+
+<p>and </p>
+
+<pre> basic_istream& operator>>(basic_streammbuf*);</pre>
+
+<p>There is a similar ambiguity for unformatted input, formatted output, and unformatted
+output. </p>
+
+<p>Comments from Judy Ward: It seems like the problem is that the
+basic_istream and basic_ostream operator <<()'s that are used
+for the manipulators and streambuf* are in the wrong section and
+should have their own separate section or be modified to make it clear
+that the "Common requirements" listed in section 27.6.1.2.1
+(for basic_istream) and section 27.6.2.5.1 (for basic_ostream) do not
+apply to them. </p>
+
+<p>Additional comments from Dietmar Kühl: It appears to be somewhat
+nonsensical to consider the functions defined in 27.6.1.2.3 paragraphs 1 to 5 to be "Formatted input
+function" but since these functions are defined in a section
+labeled "Formatted input functions" it is unclear to me
+whether these operators are considered formatted input functions which
+have to conform to the "common requirements" from 27.6.1.2.1 : If this is the case, all manipulators, not
+just <tt>ws</tt>, would skip whitespace unless <tt>noskipws</tt> is
+set (... but setting <tt>noskipws</tt> using the manipulator syntax
+would also skip whitespace :-)</p> <p>It is not clear which functions
+are to be considered unformatted input functions. As written, it seems
+that all functions in 27.6.1.3 are unformatted input
+functions. However, it does not really make much sense to construct a
+sentry object for <tt>gcount()</tt>, <tt>sync()</tt>, ... Also it is
+unclear what happens to the <tt>gcount()</tt> if
+eg. <tt>gcount()</tt>, <tt>putback()</tt>, <tt>unget()</tt>, or
+<tt>sync()</tt> is called: These functions don't extract characters,
+some of them even "unextract" a character. Should this still
+be reflected in <tt>gcount()</tt>? Of course, it could be read as if
+after a call to <tt>gcount()</tt> <tt>gcount()</tt> return <tt>0</tt>
+(the last unformatted input function, <tt>gcount()</tt>, didn't
+extract any character) and after a call to <tt>putback()</tt>
+<tt>gcount()</tt> returns <tt>-1</tt> (the last unformatted input
+function <tt>putback()</tt> did "extract" back into the
+stream). Correspondingly for <tt>unget()</tt>. Is this what is
+intended? If so, this should be clarified. Otherwise, a corresponding
+clarification should be used.</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In 27.6.1.2.2 [lib.istream.formatted.arithmetic], paragraph 1.
+Change the beginning of the second sentence from "The conversion
+occurs" to "These extractors behave as formatted input functions (as
+described in 27.6.1.2.1). After a sentry object is constructed,
+the conversion occurs"
+</p>
+
+<p>
+In 27.6.1.2.3, [lib.istream::extractors], before paragraph 1.
+Add an effects clause. "Effects: None. This extractor does
+not behave as a formatted input function (as described in
+27.6.1.2.1).
+</p>
+
+<p>
+In 27.6.1.2.3, [lib.istream::extractors], paragraph 2. Change the
+effects clause to "Effects: Calls pf(*this). This extractor does not
+behave as a formatted input function (as described in 27.6.1.2.1).
+</p>
+
+<p>
+In 27.6.1.2.3, [lib.istream::extractors], paragraph 4. Change the
+effects clause to "Effects: Calls pf(*this). This extractor does not
+behave as a formatted input function (as described in 27.6.1.2.1).
+</p>
+
+<p>
+In 27.6.1.2.3, [lib.istream::extractors], paragraph 12. Change the
+first two sentences from "If sb is null, calls setstate(failbit),
+which may throw ios_base::failure (27.4.4.3). Extracts characters
+from *this..." to "Behaves as a formatted input function (as described
+in 27.6.1.2.1). If sb is null, calls setstate(failbit), which may
+throw ios_base::failure (27.4.4.3). After a sentry object is
+constructed, extracts characters from *this...".
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], before paragraph 2. Add an
+effects clause. "Effects: none. This member function does not behave
+as an unformatted input function (as described in 27.6.1.3, paragraph 1)."
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 3. Change the
+beginning of the first sentence of the effects clause from "Extracts a
+character" to "Behaves as an unformatted input function (as described
+in 27.6.1.3, paragraph 1). After constructing a sentry object, extracts a
+character"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 5. Change the
+beginning of the first sentence of the effects clause from "Extracts a
+character" to "Behaves as an unformatted input function (as described
+in 27.6.1.3, paragraph 1). After constructing a sentry object, extracts a
+character"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 5. Change the
+beginning of the first sentence of the effects clause from "Extracts
+characters" to "Behaves as an unformatted input function (as described
+in 27.6.1.3, paragraph 1). After constructing a sentry object, extracts
+characters"
+</p>
+
+<p>
+[No change needed in paragraph 10, because it refers to paragraph 7.]
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 12. Change the
+beginning of the first sentence of the effects clause from "Extracts
+characters" to "Behaves as an unformatted input function (as described
+in 27.6.1.3, paragraph 1). After constructing a sentry object, extracts
+characters"
+</p>
+
+<p>
+[No change needed in paragraph 15.]
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 17. Change the
+beginning of the first sentence of the effects clause from "Extracts
+characters" to "Behaves as an unformatted input function (as described
+in 27.6.1.3, paragraph 1). After constructing a sentry object, extracts
+characters"
+</p>
+
+<p>
+[No change needed in paragraph 23.]
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 24. Change the
+beginning of the first sentence of the effects clause from "Extracts
+characters" to "Behaves as an unformatted input function (as described
+in 27.6.1.3, paragraph 1). After constructing a sentry object, extracts
+characters"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], before paragraph 27. Add an
+Effects clause: "Effects: Behaves as an unformatted input function (as
+described in 27.6.1.3, paragraph 1). After constructing a sentry
+object, reads but does not extract the current input character."
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 28. Change the
+first sentence of the Effects clause from "If !good() calls" to
+Behaves as an unformatted input function (as described in 27.6.1.3,
+paragraph 1). After constructing a sentry object, if !good() calls"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 30. Change the
+first sentence of the Effects clause from "If !good() calls" to
+"Behaves as an unformatted input function (as described in 27.6.1.3,
+paragraph 1). After constructing a sentry object, if !good() calls"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 32. Change the
+first sentence of the Effects clause from "If !good() calls..." to
+"Behaves as an unformatted input function (as described in 27.6.1.3,
+paragraph 1). After constructing a sentry object, if !good()
+calls..." Add a new sentence to the end of the Effects clause:
+"[Note: this function extracts no characters, so the value returned
+by the next call to gcount() is 0.]"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 34. Change the
+first sentence of the Effects clause from "If !good() calls" to
+"Behaves as an unformatted input function (as described in 27.6.1.3,
+paragraph 1). After constructing a sentry object, if !good() calls".
+Add a new sentence to the end of the Effects clause: "[Note: this
+function extracts no characters, so the value returned by the next
+call to gcount() is 0.]"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 36. Change the
+first sentence of the Effects clause from "If !rdbuf() is" to "Behaves
+as an unformatted input function (as described in 27.6.1.3, paragraph
+1), except that it does not count the number of characters extracted
+and does not affect the value returned by subsequent calls to
+gcount(). After constructing a sentry object, if rdbuf() is"
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], before paragraph 37. Add an
+Effects clause: "Effects: Behaves as an unformatted input function (as
+described in 27.6.1.3, paragraph 1), except that it does not count the
+number of characters extracted and does not affect the value returned
+by subsequent calls to gcount()." Change the first sentence of
+paragraph 37 from "if fail()" to "after constructing a sentry object,
+if fail()".
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 38. Change the
+first sentence of the Effects clause from "If fail()" to "Behaves
+as an unformatted input function (as described in 27.6.1.3, paragraph
+1), except that it does not count the number of characters extracted
+and does not affect the value returned by subsequent calls to
+gcount(). After constructing a sentry object, if fail()
+</p>
+
+<p>
+In 27.6.1.3, [lib.istream.unformatted], paragraph 40. Change the
+first sentence of the Effects clause from "If fail()" to "Behaves
+as an unformatted input function (as described in 27.6.1.3, paragraph
+1), except that it does not count the number of characters extracted
+and does not affect the value returned by subsequent calls to
+gcount(). After constructing a sentry object, if fail()
+</p>
+
+<p>
+In 27.6.2.5.2 [lib.ostream.inserters.arithmetic], paragraph 1. Change
+the beginning of the third sentence from "The formatting conversion"
+to "These extractors behave as formatted output functions (as
+described in 27.6.2.5.1). After the sentry object is constructed, the
+conversion occurs".
+</p>
+
+<p>
+In 27.6.2.5.3 [lib.ostream.inserters], before paragraph 1. Add an
+effects clause: "Effects: None. Does not behave as a formatted output
+function (as described in 27.6.2.5.1).".
+</p>
+
+<p>
+In 27.6.2.5.3 [lib.ostream.inserters], paragraph 2. Change the
+effects clause to "Effects: calls pf(*this). This extractor does not
+behave as a formatted output function (as described in 27.6.2.5.1).".
+</p>
+
+<p>
+In 27.6.2.5.3 [lib.ostream.inserters], paragraph 4. Change the
+effects clause to "Effects: calls pf(*this). This extractor does not
+behave as a formatted output function (as described in 27.6.2.5.1).".
+</p>
+
+<p>
+In 27.6.2.5.3 [lib.ostream.inserters], paragraph 6. Change the first
+sentence from "If sb" to "Behaves as a formatted output function (as
+described in 27.6.2.5.1). After the sentry object is constructed, if
+sb".
+</p>
+
+<p>
+In 27.6.2.6 [lib.ostream.unformatted], paragraph 2. Change the first
+sentence from "Inserts the character" to "Behaves as an unformatted
+output function (as described in 27.6.2.6, paragraph 1). After
+constructing a sentry object, inserts the character".
+</p>
+
+<p>
+In 27.6.2.6 [lib.ostream.unformatted], paragraph 5. Change the first
+sentence from "Obtains characters" to "Behaves as an unformatted
+output function (as described in 27.6.2.6, paragraph 1). After
+constructing a sentry object, obtains characters".
+</p>
+
+<p>
+In 27.6.2.6 [lib.ostream.unformatted], paragraph 7. Add a new
+sentence at the end of the paragraph: "Does not behave as an
+unformatted output function (as described in 27.6.2.6, paragraph 1)."
+</p>
+<p><b>Rationale:</b></p>
+<p>See J16/99-0043==WG21/N1219, Proposed Resolution to Library Issue 60,
+by Judy Ward and Matt Austern. This proposed resolution is section
+VI of that paper.</p>
+<hr>
+<a name="61"><h3>61. Ambiguity in iostreams exception policy</h3></a><p>
+<b>Section:</b> 27.6.1.3 <a href="lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 6 Aug 1998</p>
+<p>The introduction to the section on unformatted input (27.6.1.3)
+says that every unformatted input function catches all exceptions that
+were thrown during input, sets badbit, and then conditionally rethrows
+the exception. That seems clear enough. Several of the specific
+functions, however, such as get() and read(), are documented in some
+circumstances as setting eofbit and/or failbit. (The standard notes,
+correctly, that setting eofbit or failbit can sometimes result in an
+exception being thrown.) The question: if one of these functions
+throws an exception triggered by setting failbit, is this an exception
+"thrown during input" and hence covered by 27.6.1.3, or does
+27.6.1.3 only refer to a limited class of exceptions? Just to make
+this concrete, suppose you have the following snippet. </p>
+
+<pre>
+ char buffer[N];
+ istream is;
+ ...
+ is.exceptions(istream::failbit); // Throw on failbit but not on badbit.
+ is.read(buffer, N);</pre>
+
+<p>Now suppose we reach EOF before we've read N characters. What
+iostate bits can we expect to be set, and what exception (if any) will
+be thrown? </p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In 27.6.1.3, paragraph 1, after the sentence that begins
+"If an exception is thrown...", add the following
+parenthetical comment: "(Exceptions thrown from
+<tt>basic_ios<>::clear()</tt> are not caught or rethrown.)"
+</p>
+<p><b>Rationale:</b></p>
+<p>The LWG looked to two alternative wordings, and choose the proposed
+resolution as better standardese.</p>
+<hr>
+<a name="62"><h3>62. <tt>Sync</tt>'s return value</h3></a><p>
+<b>Section:</b> 27.6.1.3 <a href="lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 6 Aug 1998</p>
+<p>The Effects clause for sync() (27.6.1.3, paragraph 36) says that it
+"calls rdbuf()->pubsync() and, if that function returns -1
+... returns traits::eof()." </p>
+
+<p>That looks suspicious, because traits::eof() is of type
+traits::int_type while the return type of sync() is int. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.6.1.3 , paragraph 36, change "returns
+<tt>traits::eof()</tt>" to "returns <tt>-1</tt>".
+</p>
+<hr>
+<a name="63"><h3>63. Exception-handling policy for unformatted output</h3></a><p>
+<b>Section:</b> 27.6.2.6 <a href="lib-iostreams.html#lib.ostream.unformatted"> [lib.ostream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 11 Aug 1998</p>
+<p>Clause 27 details an exception-handling policy for formatted input,
+unformatted input, and formatted output. It says nothing for
+unformatted output (27.6.2.6). 27.6.2.6 should either include the same
+kind of exception-handling policy as in the other three places, or
+else it should have a footnote saying that the omission is
+deliberate. </p>
+<p><b>Proposed resolution:</b></p>
+<p>
+In 27.6.2.6, paragraph 1, replace the last sentence ("In any
+case, the unformatted output function ends by destroying the sentry
+object, then returning the value specified for the formatted output
+function.") with the following text:
+</p>
+<blockquote>
+If an exception is thrown during output, then <tt>ios::badbit</tt> is
+turned on [Footnote: without causing an <tt>ios::failure</tt> to be
+thrown.] in <tt>*this</tt>'s error state. If <tt>(exceptions() &
+badbit) != 0</tt> then the exception is rethrown. In any case, the
+unformatted output function ends by destroying the sentry object,
+then, if no exception was thrown, returning the value specified for
+the formatted output function.
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>
+This exception-handling policy is consistent with that of formatted
+input, unformatted input, and formatted output.
+</p>
+<hr>
+<a name="64"><h3>64. Exception handling in <tt>basic_istream::operator>>(basic_streambuf*)</tt>
+</h3></a><p>
+<b>Section:</b> 27.6.1.2.3 <a href="lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 11 Aug 1998 </p>
+<p>27.6.1.2.3, paragraph 13, is ambiguous. It can be interpreted two
+different ways, depending on whether the second sentence is read as an
+elaboration of the first. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace 27.6.1.2.3 , paragraph 13, which begins
+"If the function inserts no characters ..." with:</p>
+
+<blockquote>
+ <p>If the function inserts no characters, it calls
+ <tt>setstate(failbit)</tt>, which may throw
+ <tt>ios_base::failure</tt> (27.4.4.3). If it inserted no characters
+ because it caught an exception thrown while extracting characters
+ from <tt>sb</tt> and <tt>failbit</tt> is on in <tt>exceptions()</tt>
+ (27.4.4.3), then the caught exception is rethrown. </p>
+</blockquote>
+<hr>
+<a name="66"><h3>66. Strstreambuf::setbuf</h3></a><p>
+<b>Section:</b> D.7.1.3 <a href="future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 18 Aug 1998</p>
+<p>D.7.1.3, paragraph 19, says that strstreambuf::setbuf
+"Performs an operation that is defined separately for each class
+derived from strstreambuf". This is obviously an incorrect
+cut-and-paste from basic_streambuf. There are no classes derived from
+strstreambuf. </p>
+<p><b>Proposed resolution:</b></p>
+<p>D.7.1.3 , paragraph 19, replace the setbuf effects
+clause which currently says "Performs an operation that is
+defined separately for each class derived from strstreambuf"
+with:<a href="future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>
+</p>
+
+<blockquote>
+ <p>
+<b>Effects</b>: implementation defined, except that
+ <tt>setbuf(0,0)</tt> has no effect.</p>
+</blockquote>
+<hr>
+<a name="68"><h3>68. Extractors for char* should store null at end</h3></a><p>
+<b>Section:</b> 27.6.1.2.3 <a href="lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> 14 Jul 1998</p>
+<p>Extractors for char* (27.6.1.2.3) do not store a null character
+after the extracted character sequence whereas the unformatted
+functions like get() do. Why is this?</p>
+
+<p>Comment from Jerry Schwarz: There is apparently an editing
+glitch. You'll notice that the last item of the list of what stops
+extraction doesn't make any sense. It was supposed to be the line that
+said a null is stored.</p>
+<p><b>Proposed resolution:</b></p>
+<p>27.6.1.2.3 , paragraph 7, change the last list
+item from:<a href="lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>
+</p>
+
+<blockquote>
+ A null byte (<tt>charT()</tt>) in the next position, which may be
+ the first position if no characters were extracted.
+</blockquote>
+
+<p>to become a new paragraph which reads:</p>
+
+<blockquote>
+ Operator>> then stores a null byte (<tt>charT()</tt>) in the
+ next position, which may be the first position if no characters were
+ extracted.
+</blockquote>
+<hr>
+<a name="69"><h3>69. Must elements of a vector be contiguous?</h3></a><p>
+<b>Section:</b> 23.2.4 <a href="lib-containers.html#lib.vector"> [lib.vector]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 29 Jul 1998</p>
+<p>The issue is this: Must the elements of a vector be in contiguous memory?</p>
+
+<p>(Please note that this is entirely separate from the question of
+whether a vector iterator is required to be a pointer; the answer to
+that question is clearly "no," as it would rule out
+debugging implementations)</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following text to the end of 23.2.4 ,
+paragraph 1. </p>
+
+<blockquote>
+ <p>The elements of a vector are stored contiguously, meaning that if
+ v is a <tt>vector<T, Allocator></tt> where T is some type
+ other than <tt>bool</tt>, then it obeys the identity <tt>&v[n]
+ == &v[0] + n</tt> for all <tt>0 <= n < v.size()</tt>.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The LWG feels that as a practical matter the answer is clearly
+"yes". There was considerable discussion as to the best way
+to express the concept of "contiguous", which is not
+directly defined in the standard. Discussion included:</p>
+
+<ul>
+ <li>An operational definition similar to the above proposed resolution is
+ already used for valarray (26.3.2.3 ).</li>
+ <li>There is no need to explicitly consider a user-defined operator&
+ because elements must be copyconstructible (23.1 para 3)
+ and copyconstructible (20.1.3 ) specifies
+ requirements for operator&.</li>
+ <li>There is no issue of one-past-the-end because of language rules.</li>
+</ul>
+<hr>
+<a name="70"><h3>70. Uncaught_exception() missing throw() specification</h3></a><p>
+<b>Section:</b> 18.6 <a href="lib-support.html#lib.support.exception"> [lib.support.exception]</a>, 18.6.4 <a href="lib-support.html#lib.uncaught"> [lib.uncaught]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> Unknown</p>
+<p>In article 3E04@pratique.fr, Valentin Bonnard writes: </p>
+
+<p>uncaught_exception() doesn't have a throw specification.</p>
+
+<p>It is intentional ? Does it means that one should be prepared to
+handle exceptions thrown from uncaught_exception() ?</p>
+
+<p>uncaught_exception() is called in exception handling contexts where
+exception safety is very important.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 15.5.3 , paragraph 1, 18.6 , and 18.6.4 , add "throw()" to uncaught_exception().</p>
+<hr>
+<a name="71"><h3>71. Do_get_monthname synopsis missing argument</h3></a><p>
+<b>Section:</b> 22.2.5.1 <a href="lib-locales.html#lib.locale.time.get"> [lib.locale.time.get]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 13 Aug 1998</p>
+<p>The locale facet member <tt>time_get<>::do_get_monthname</tt>
+is described in 22.2.5.1.2 with five arguments,
+consistent with do_get_weekday and with its specified use by member
+get_monthname. However, in the synopsis, it is specified instead with
+four arguments. The missing argument is the "end" iterator
+value.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.5.1 , add an "end" argument to
+the declaration of member do_monthname as follows:</p>
+
+<pre> virtual iter_type do_get_monthname(iter_type s, iter_type end, ios_base&,
+ ios_base::iostate& err, tm* t) const;</pre>
+<hr>
+<a name="74"><h3>74. Garbled text for <tt>codecvt::do_max_length</tt>
+</h3></a><p>
+<b>Section:</b> 22.2.1.5.2 <a href="lib-locales.html#lib.locale.codecvt.virtuals"> [lib.locale.codecvt.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 8 Sep 1998</p>
+<p>The text of <tt>codecvt::do_max_length</tt>'s "Returns"
+clause (22.2.1.5.2, paragraph 11) is garbled. It has unbalanced
+parentheses and a spurious <b>n</b>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace 22.2.1.5.2 paragraph 11 with the
+following:</p>
+
+<blockquote>
+ <b>Returns</b>: The maximum value that
+ <tt>do_length(state, from, from_end, 1)</tt> can return for any
+ valid range <tt>[from, from_end)</tt> and <tt>stateT</tt> value
+ <tt>state</tt>. The specialization <tt>codecvt<char, char,
+ mbstate_t>::do_max_length()</tt> returns 1.
+</blockquote>
+<hr>
+<a name="75"><h3>75. Contradiction in <tt>codecvt::length</tt>'s argument types</h3></a><p>
+<b>Section:</b> 22.2.1.5 <a href="lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt
+Austern <b>Date:</b> 18 Sep 1998</p>
+<p>The class synopses for classes <tt>codecvt<></tt> (22.2.1.5)
+and <tt>codecvt_byname<></tt> (22.2.1.6) say that the first
+parameter of the member functions <tt>length</tt> and
+<tt>do_length</tt> is of type <tt>const stateT&</tt>. The member
+function descriptions, however (22.2.1.5.1, paragraph 6; 22.2.1.5.2,
+paragraph 9) say that the type is <tt>stateT&</tt>. Either the
+synopsis or the summary must be changed. </p>
+
+<p>If (as I believe) the member function descriptions are correct,
+then we must also add text saying how <tt>do_length</tt> changes its
+<tt>stateT</tt> argument. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.1.5 , and also in 22.2.1.6 ,
+change the <tt>stateT</tt> argument type on both member
+<tt>length()</tt> and member <tt>do_length()</tt> from </p>
+
+<blockquote>
+ <p><tt>const stateT&</tt></p>
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+ <p><tt>stateT&</tt></p>
+</blockquote>
+
+<p>In 22.2.1.5.2 , add to the definition for member
+<tt>do_length</tt> a paragraph:</p>
+
+<blockquote>
+ <p>Effects: The effect on the <tt>state</tt> argument is ``as if''
+ it called <tt>do_in(state, from, from_end, from, to, to+max,
+ to)</tt> for <tt>to</tt> pointing to a buffer of at least
+ <tt>max</tt> elements.</p>
+</blockquote>
+<hr>
+<a name="78"><h3>78. Typo: event_call_back</h3></a><p>
+<b>Section:</b> 27.4.2 <a href="lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>typo: event_call_back should be event_callback </p>
+<p><b>Proposed resolution:</b></p>
+<p>In the 27.4.2 synopsis change
+"event_call_back" to "event_callback". </p>
+<hr>
+<a name="79"><h3>79. Inconsistent declaration of polar()</h3></a><p>
+<b>Section:</b> 26.2.1 <a href="lib-numerics.html#lib.complex.synopsis"> [lib.complex.synopsis]</a>, 26.2.7 <a href="lib-numerics.html#lib.complex.value.ops"> [lib.complex.value.ops]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>In 26.2.1 polar is declared as follows:</p>
+<pre> template<class T> complex<T> polar(const T&, const T&); </pre>
+
+<p>In 26.2.7 it is declared as follows:</p>
+<pre> template<class T> complex<T> polar(const T& rho, const T& theta = 0); </pre>
+
+<p>Thus whether the second parameter is optional is not clear. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 26.2.1 change:</p>
+<pre> template<class T> complex<T> polar(const T&, const T&);</pre>
+
+<p>to:</p>
+<pre> template<class T> complex<T> polar(const T& rho, const T& theta = 0); </pre>
+<hr>
+<a name="80"><h3>80. Global Operators of complex declared twice</h3></a><p>
+<b>Section:</b> 26.2.1 <a href="lib-numerics.html#lib.complex.synopsis"> [lib.complex.synopsis]</a>, 26.2.2 <a href="lib-numerics.html#lib.complex"> [lib.complex]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>Both 26.2.1 and 26.2.2 contain declarations of global operators for
+class complex. This redundancy should be removed.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Reduce redundancy according to the general style of the standard. </p>
+<hr>
+<a name="83"><h3>83. String::npos vs. string::max_size()</h3></a><p>
+<b>Section:</b> 21.3 <a href="lib-strings.html#lib.basic.string"> [lib.basic.string]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>Many string member functions throw if size is getting or exceeding
+npos. However, I wonder why they don't throw if size is getting or
+exceeding max_size() instead of npos. May be npos is known at compile
+time, while max_size() is known at runtime. However, what happens if
+size exceeds max_size() but not npos, then? It seems the standard
+lacks some clarifications here.</p>
+<p><b>Proposed resolution:</b></p>
+<p>After 21.3 paragraph 4 ("The functions
+described in this clause...") add a new paragraph:</p>
+
+<blockquote>
+ <p>For any string operation, if as a result of the operation, <tt> size()</tt> would exceed
+ <tt> max_size()</tt> then
+ the operation throws <tt>length_error</tt>.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The LWG believes length_error is the correct exception to throw.</p>
+<hr>
+<a name="86"><h3>86. String constructors don't describe exceptions</h3></a><p>
+<b>Section:</b> 21.3.1 <a href="lib-strings.html#lib.string.cons"> [lib.string.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>The constructor from a range:</p>
+
+<pre>template<class InputIterator>
+ basic_string(InputIterator begin, InputIterator end,
+ const Allocator& a = Allocator());</pre>
+
+<p>lacks a throws clause. However, I would expect that it throws
+according to the other constructors if the numbers of characters in
+the range equals npos (or exceeds max_size(), see above). </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 21.3.1 , Strike throws paragraphs for
+constructors which say "Throws: length_error if n ==
+npos."</p>
+<p><b>Rationale:</b></p>
+<p>Throws clauses for length_error if n == npos are no longer needed
+because they are subsumed by the general wording added by the
+resolution for issue <a href="lwg-defects.html#83">83</a>.</p>
+<hr>
+<a name="90"><h3>90. Incorrect description of operator >> for strings</h3></a><p>
+<b>Section:</b> 21.3.7.9 <a href="lib-strings.html#lib.string.io"> [lib.string.io]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 29 Sep 1998</p>
+<p>The effect of operator >> for strings contain the following item:</p>
+
+<p> <tt>isspace(c,getloc())</tt> is true for the next available input
+character c.</p>
+
+<p>Here <tt>getloc()</tt> has to be replaced by <tt>is.getloc()</tt>. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 21.3.7.9 paragraph 1 Effects clause replace:</p>
+
+<blockquote>
+ <p>
+<tt>isspace(c,getloc())</tt> is true for the next available input character c.</p>
+</blockquote>
+
+<p>with:</p>
+
+<blockquote>
+ <p>
+<tt>isspace(c,is.getloc())</tt> is true for the next available input character c.</p>
+</blockquote>
+<hr>
+<a name="103"><h3>103. set::iterator is required to be modifiable, but this allows modification of keys</h3></a><p>
+<b>Section:</b> 23.1.2 <a href="lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> AFNOR <b>Date:</b> 7 Oct 1998</p>
+<p>Set::iterator is described as implementation-defined with a
+reference to the container requirement; the container requirement says
+that const_iterator is an iterator pointing to const T and iterator an
+iterator pointing to T.</p>
+
+<p>23.1.2 paragraph 2 implies that the keys should not be modified to
+break the ordering of elements. But that is not clearly
+specified. Especially considering that the current standard requires
+that iterator for associative containers be different from
+const_iterator. Set, for example, has the following: </p>
+
+<p><tt>typedef implementation defined iterator;<br>
+ // See _lib.container.requirements_</tt></p>
+
+<p>23.1 actually requires that iterator type pointing
+to T (table 65). Disallowing user modification of keys by changing the
+standard to require an iterator for associative container to be the
+same as const_iterator would be overkill since that will unnecessarily
+significantly restrict the usage of associative container. A class to
+be used as elements of set, for example, can no longer be modified
+easily without either redesigning the class (using mutable on fields
+that have nothing to do with ordering), or using const_cast, which
+defeats requiring iterator to be const_iterator. The proposed solution
+goes in line with trusting user knows what he is doing. <a href="lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>
+</p>
+
+<p>
+<b>Other Options Evaluated:</b> </p>
+
+<p>Option A. In 23.1.2 , paragraph 2, after
+first sentence, and before "In addition,...", add one line:
+</p>
+
+<blockquote>
+ <p>Modification of keys shall not change their strict weak ordering. </p>
+</blockquote>
+
+<p>Option B. Add three new sentences to 23.1.2 :</p>
+
+<blockquote>
+ <p>At the end of paragraph 5: "Keys in an associative container
+ are immutable." At the end of paragraph 6: "For
+ associative containers where the value type is the same as the key
+ type, both <tt>iterator</tt> and <tt>const_iterator</tt> are
+ constant iterators. It is unspecified whether or not
+ <tt>iterator</tt> and <tt>const_iterator</tt> are the same
+ type."</p>
+</blockquote>
+
+<p>Option C. To 23.1.2 , paragraph 3, which
+currently reads:</p>
+
+<blockquote>
+ <p>The phrase ``equivalence of keys'' means the equivalence relation imposed by the
+ comparison and not the operator== on keys. That is, two keys k1 and k2 in the same
+ container are considered to be equivalent if for the comparison object comp, comp(k1, k2)
+ == false && comp(k2, k1) == false.</p>
+</blockquote>
+
+<p> add the following:</p>
+
+<blockquote>
+ <p>For any two keys k1 and k2 in the same container, comp(k1, k2) shall return the same
+ value whenever it is evaluated. [Note: If k2 is removed from the container and later
+ reinserted, comp(k1, k2) must still return a consistent value but this value may be
+ different than it was the first time k1 and k2 were in the same container. This is
+ intended to allow usage like a string key that contains a filename, where comp compares
+ file contents; if k2 is removed, the file is changed, and the same k2 (filename) is
+ reinserted, comp(k1, k2) must again return a consistent value but this value may be
+ different than it was the previous time k2 was in the container.]</p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following to 23.1.2 at
+the indicated location:</p>
+
+<blockquote>
+ <p>At the end of paragraph 3: "For any two keys k1 and k2 in the same container,
+ calling comp(k1, k2) shall always return the same
+ value."</p>
+ <p>At the end of paragraph 5: "Keys in an associative container are immutable."</p>
+ <p>At the end of paragraph 6: "For associative containers where the value type is the
+ same as the key type, both <tt>iterator</tt> and <tt>const_iterator</tt> are constant
+ iterators. It is unspecified whether or not <tt>iterator</tt> and <tt>const_iterator</tt>
+ are the same type."</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Several arguments were advanced for and against allowing set elements to be
+mutable as long as the ordering was not effected. The argument which swayed the
+LWG was one of safety; if elements were mutable, there would be no compile-time
+way to detect of a simple user oversight which caused ordering to be
+modified. There was a report that this had actually happened in practice,
+and had been painful to diagnose. If users need to modify elements,
+it is possible to use mutable members or const_cast.</p>
+
+<p>Simply requiring that keys be immutable is not sufficient, because the comparison
+object may indirectly (via pointers) operate on values outside of the keys.</p>
+
+<p>
+The types <tt>iterator</tt> and <tt>const_iterator</tt> are permitted
+to be different types to allow for potential future work in which some
+member functions might be overloaded between the two types. No such
+member functions exist now, and the LWG believes that user functionality
+will not be impaired by permitting the two types to be the same. A
+function that operates on both iterator types can be defined for
+<tt>const_iterator</tt> alone, and can rely on the automatic
+conversion from <tt>iterator</tt> to <tt>const_iterator</tt>.
+</p>
+
+<p><i>[Tokyo: The LWG crafted the proposed resolution and rationale.]</i></p>
+<hr>
+<a name="106"><h3>106. Numeric library private members are implementation defined</h3></a><p>
+<b>Section:</b> 26.3.5 <a href="lib-numerics.html#lib.template.slice.array"> [lib.template.slice.array]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> AFNOR <b>Date:</b> 7 Oct 1998</p>
+<p>This is the only place in the whole standard where the implementation has to document
+something private.</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Remove the comment which says "// remainder implementation defined" from:
+</p>
+
+<ul>
+ <li>26.3.5 <a href="lib-numerics.html#lib.template.slice.array"> [lib.template.slice.array]</a>
+</li>
+ <li>26.3.7 <a href="lib-numerics.html#lib.template.gslice.array"> [lib.template.gslice.array]</a>
+</li>
+ <li>26.3.8 <a href="lib-numerics.html#lib.template.mask.array"> [lib.template.mask.array]</a>
+</li>
+ <li>26.3.9 <a href="lib-numerics.html#lib.template.indirect.array"> [lib.template.indirect.array]</a>
+</li>
+</ul>
+<hr>
+<a name="108"><h3>108. Lifetime of exception::what() return unspecified</h3></a><p>
+<b>Section:</b> 18.6.1 <a href="lib-support.html#lib.exception"> [lib.exception]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> AFNOR <b>Date:</b> 7 Oct 1998</p>
+<p>In 18.6.1, paragraphs 8-9, the lifetime of the return value of
+exception::what() is left unspecified. This issue has implications
+with exception safety of exception handling: some exceptions should
+not throw bad_alloc.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add to 18.6.1 paragraph 9 (exception::what notes
+clause) the sentence:</p>
+
+<blockquote>
+ <p>The return value remains valid until the exception object from which it is obtained is
+ destroyed or a non-const member function of the exception object is called.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>If an exception object has non-const members, they may be used
+to set internal state that should affect the contents of the string
+returned by <tt>what()</tt>.
+</p>
+<hr>
+<a name="110"><h3>110. istreambuf_iterator::equal not const</h3></a><p>
+<b>Section:</b> 24.5.3 <a href="lib-iterators.html#lib.istreambuf.iterator"> [lib.istreambuf.iterator]</a>, 24.5.3.5 <a href="lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nathan Myers <b>Date:</b> 15 Oct 1998</p>
+<p>Member istreambuf_iterator<>::equal is not declared
+"const", yet 24.5.3.6 says that operator==,
+which is const, calls it. This is contradictory. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 24.5.3 and also in 24.5.3.5 ,
+replace:</p>
+
+<blockquote>
+ <pre>bool equal(istreambuf_iterator& b);</pre>
+</blockquote>
+
+<p>with:</p>
+
+<blockquote>
+ <pre>bool equal(const istreambuf_iterator& b) const;</pre>
+</blockquote>
+<hr>
+<a name="112"><h3>112. Minor typo in <tt>ostreambuf_iterator</tt> constructor</h3></a><p>
+<b>Section:</b> 24.5.4.1 <a href="lib-iterators.html#lib.ostreambuf.iter.cons"> [lib.ostreambuf.iter.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 20 Oct 1998</p>
+<p>The <b>requires</b> clause for <tt>ostreambuf_iterator</tt>'s
+constructor from an <tt>ostream_type</tt> (24.5.4.1, paragraph 1)
+reads "<i>s</i> is not null". However, <i>s</i> is a
+reference, and references can't be null. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 24.5.4.1 :</p>
+
+<p>Move the current paragraph 1, which reads "Requires: s is not
+null.", from the first constructor to the second constructor.</p>
+
+<p>Insert a new paragraph 1 Requires clause for the first constructor
+reading:</p>
+
+<blockquote>
+ <p>
+<b>Requires</b>: <tt>s.rdbuf()</tt> is not null.</p>
+</blockquote>
+<hr>
+<a name="114"><h3>114. Placement forms example in error twice</h3></a><p>
+<b>Section:</b> 18.4.1.3 <a href="lib-support.html#lib.new.delete.placement"> [lib.new.delete.placement]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 28 Oct 1998</p>
+<p>Section 18.4.1.3 contains the following example: </p>
+
+<pre>[Example: This can be useful for constructing an object at a known address:
+ char place[sizeof(Something)];
+ Something* p = new (place) Something();
+ -end example]</pre>
+
+<p>First code line: "place" need not have any special alignment, and the
+following constructor could fail due to misaligned data.</p>
+
+<p>Second code line: Aren't the parens on Something() incorrect? [Dublin: the LWG
+believes the () are correct.]</p>
+
+<p>Examples are not normative, but nevertheless should not show code that is invalid or
+likely to fail.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace the <u> first line of code</u> in the example in
+18.4.1.3 with:
+</p>
+
+<blockquote>
+ <pre>void* place = operator new(sizeof(Something));</pre>
+</blockquote>
+<hr>
+<a name="115"><h3>115. Typo in strstream constructors</h3></a><p>
+<b>Section:</b> D.7.4.1 <a href="future.html#depr.strstream.cons"> [depr.strstream.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Steve Clamage <b>Date:</b> 2 Nov 1998</p>
+<p>D.7.4.1 strstream constructors paragraph 2 says: </p>
+
+<blockquote>
+ <p>Effects: Constructs an object of class strstream, initializing the base class with
+ iostream(& sb) and initializing sb with one of the two constructors: </p>
+ <p>- If mode&app==0, then s shall designate the first element of an array of n
+ elements. The constructor is strstreambuf(s, n, s). </p>
+ <p>- If mode&app==0, then s shall designate the first element of an array of n
+ elements that contains an NTBS whose first element is designated by s. The constructor is
+ strstreambuf(s, n, s+std::strlen(s)).</p>
+</blockquote>
+
+<p>Notice the second condition is the same as the first. I think the second condition
+should be "If mode&app==app", or "mode&app!=0", meaning that
+the append bit is set.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In D.7.3.1 paragraph 2 and D.7.4.1
+paragraph 2, change the first condition to <tt>(mode&app)==0</tt>
+and the second condition to <tt>(mode&app)!=0</tt>.</p>
+<hr>
+<a name="118"><h3>118. <tt>basic_istream</tt> uses nonexistent <tt>num_get</tt> member functions</h3></a><p>
+<b>Section:</b> 27.6.1.2.2 <a href="lib-iostreams.html#lib.istream.formatted.arithmetic"> [lib.istream.formatted.arithmetic]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 20 Nov 1998</p>
+<p>Formatted input is defined for the types <tt>short</tt>, <tt>unsigned short</tt>, <tt>int</tt>,
+<tt>unsigned int</tt>, <tt>long</tt>, <tt>unsigned long</tt>, <tt>float</tt>, <tt>double</tt>,
+<tt>long double</tt>, <tt>bool</tt>, and <tt>void*</tt>. According to section 27.6.1.2.2,
+formatted input of a value <tt>x</tt> is done as if by the following code fragment: </p>
+
+<pre>typedef num_get< charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = 0;
+use_facet< numget >(loc).get(*this, 0, *this, err, val);
+setstate(err);</pre>
+
+<p>According to section 22.2.2.1.1 , however,
+<tt>num_get<>::get()</tt> is only overloaded for the types
+<tt>bool</tt>, <tt>long</tt>, <tt>unsigned short</tt>, <tt>unsigned
+int</tt>, <tt>unsigned long</tt>, <tt>unsigned long</tt>,
+<tt>float</tt>, <tt>double</tt>, <tt>long double</tt>, and
+<tt>void*</tt>. Comparing the lists from the two sections, we find
+that 27.6.1.2.2 is using a nonexistent function for types
+<tt>short</tt> and <tt>int</tt>. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.6.1.2.2 Arithmetic Extractors, remove the
+two lines (1st and 3rd) which read:</p>
+<blockquote>
+ <pre>operator>>(short& val);
+...
+operator>>(int& val);</pre>
+</blockquote>
+
+<p>And add the following at the end of that section (27.6.1.2.2) :</p>
+
+<blockquote>
+ <pre>operator>>(short& val);</pre>
+ <p>The conversion occurs as if performed by the following code fragment (using
+ the same notation as for the preceding code fragment):</p>
+ <pre> typedef num_get< charT,istreambuf_iterator<charT,traits> > numget;
+ iostate err = 0;
+ long lval;
+ use_facet< numget >(loc).get(*this, 0, *this, err, lval);
+ if (err == 0
+ && (lval < numeric_limits<short>::min() || numeric_limits<short>::max() < lval))
+ err = ios_base::failbit;
+ setstate(err);</pre>
+ <pre>operator>>(int& val);</pre>
+ <p>The conversion occurs as if performed by the following code fragment (using
+ the same notation as for the preceding code fragment):</p>
+ <pre> typedef num_get< charT,istreambuf_iterator<charT,traits> > numget;
+ iostate err = 0;
+ long lval;
+ use_facet< numget >(loc).get(*this, 0, *this, err, lval);
+ if (err == 0
+ && (lval < numeric_limits<int>::min() || numeric_limits<int>::max() < lval))
+ err = ios_base::failbit;
+ setstate(err);</pre>
+</blockquote>
+
+<p><i>[Post-Tokyo: PJP provided the above wording.]</i></p>
+<hr>
+<a name="119"><h3>119. Should virtual functions be allowed to strengthen the exception specification?</h3></a><p>
+<b>Section:</b> 17.4.4.8 <a href="lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998</p>
+<p>Section 17.4.4.8 states: </p>
+
+<p>"An implementation may strengthen the exception-specification
+for a function by removing listed exceptions." </p>
+
+<p>The problem is that if an implementation is allowed to do this for
+virtual functions, then a library user cannot write a class that
+portably derives from that class. </p>
+
+<p>For example, this would not compile if ios_base::failure::~failure
+had an empty exception specification: </p>
+
+<pre>#include <ios>
+#include <string>
+
+class D : public std::ios_base::failure {
+public:
+ D(const std::string&);
+ ~D(); // error - exception specification must be compatible with
+ // overridden virtual function ios_base::failure::~failure()
+};</pre>
+<p><b>Proposed resolution:</b></p>
+<p>Change Section 17.4.4.8 from:</p>
+
+<p> "may strengthen the
+exception-specification for a function"</p>
+
+<p>to:</p>
+
+<p> "may strengthen the
+exception-specification for a non-virtual function". </p>
+<hr>
+<a name="122"><h3>122. streambuf/wstreambuf description should not say they are specializations</h3></a><p>
+<b>Section:</b> 27.5.2 <a href="lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998</p>
+<p>Section 27.5.2 describes the streambuf classes this way: </p>
+
+<blockquote>
+
+<p>The class streambuf is a specialization of the template class basic_streambuf
+specialized for the type char. </p>
+
+<p>The class wstreambuf is a specialization of the template class basic_streambuf
+specialized for the type wchar_t. </p>
+
+</blockquote>
+
+<p>This implies that these classes must be template specializations, not typedefs. </p>
+
+<p>It doesn't seem this was intended, since Section 27.5 has them declared as typedefs. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove 27.5.2 paragraphs 2 and 3 (the above two
+sentences). </p>
+<p><b>Rationale:</b></p>
+<p>The <tt>streambuf</tt> synopsis already has a declaration for the
+typedefs and that is sufficient. </p>
+<hr>
+<a name="124"><h3>124. ctype_byname<charT>::do_scan_is & do_scan_not return type should be const charT*</h3></a><p>
+<b>Section:</b> 22.2.1.2 <a href="lib-locales.html#lib.locale.ctype.byname"> [lib.locale.ctype.byname]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998</p>
+<p>In Section 22.2.1.2
+ctype_byname<charT>::do_scan_is() and do_scan_not() are declared
+to return a const char* not a const charT*. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change Section 22.2.1.2 <tt>do_scan_is()</tt> and
+<tt>do_scan_not()</tt> to return a <tt> const
+charT*</tt>. </p>
+<hr>
+<a name="125"><h3>125. valarray<T>::operator!() return type is inconsistent</h3></a><p>
+<b>Section:</b> 26.3.2 <a href="lib-numerics.html#lib.template.valarray"> [lib.template.valarray]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998</p>
+<p>In Section 26.3.2 valarray<T>::operator!() is
+declared to return a valarray<T>, but in Section 26.3.2.5 it is declared to return a valarray<bool>. The
+latter appears to be correct. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Change in Section 26.3.2 the declaration of
+<tt>operator!()</tt> so that the return type is
+<tt>valarray<bool></tt>. </p>
+<hr>
+<a name="126"><h3>126. typos in Effects clause of ctype::do_narrow()</h3></a><p>
+<b>Section:</b> 22.2.1.1.2 <a href="lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 15 Dec 1998</p>
+<p>Typos in 22.2.1.1.2 need to be fixed.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In Section 22.2.1.1.2 change: </p>
+
+<pre> do_widen(do_narrow(c),0) == c</pre>
+
+<p>to:</p>
+
+<pre> do_widen(do_narrow(c,0)) == c</pre>
+
+<p>and change:</p>
+
+<pre> (is(M,c) || !ctc.is(M, do_narrow(c),dfault) )</pre>
+
+<p>to:</p>
+
+<pre> (is(M,c) || !ctc.is(M, do_narrow(c,dfault)) )</pre>
+<hr>
+<a name="127"><h3>127. auto_ptr<> conversion issues</h3></a><p>
+<b>Section:</b> 20.4.5 <a href="lib-utilities.html#lib.auto.ptr"> [lib.auto.ptr]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Greg Colvin <b>Date:</b> 17 Feb 1999</p>
+<p>There are two problems with the current <tt>auto_ptr</tt> wording
+in the standard: </p>
+
+<p>First, the <tt>auto_ptr_ref</tt> definition cannot be nested
+because <tt>auto_ptr<Derived>::auto_ptr_ref</tt> is unrelated to
+<tt>auto_ptr<Base>::auto_ptr_ref</tt>. <i>Also submitted by
+Nathan Myers, with the same proposed resolution.</i>
+</p>
+
+<p>Second, there is no <tt>auto_ptr</tt> assignment operator taking an
+<tt>auto_ptr_ref</tt> argument. </p>
+
+<p>I have discussed these problems with my proposal coauthor, Bill
+Gibbons, and with some compiler and library implementors, and we
+believe that these problems are not desired or desirable implications
+of the standard. </p>
+
+<p>25 Aug 1999: The proposed resolution now reflects changes suggested
+by Dave Abrahams, with Greg Colvin's concurrence; 1) changed
+"assignment operator" to "public assignment
+operator", 2) changed effects to specify use of release(), 3)
+made the conversion to auto_ptr_ref const. </p>
+
+<p>2 Feb 2000: Lisa Lippincott comments: [The resolution of] this issue
+states that the conversion from auto_ptr to auto_ptr_ref should
+be const. This is not acceptable, because it would allow
+initialization and assignment from _any_ const auto_ptr! It also
+introduces an implementation difficulty in writing this conversion
+function -- namely, somewhere along the line, a const_cast will be
+necessary to remove that const so that release() may be called. This
+may result in undefined behavior [7.1.5.1/4]. The conversion
+operator does not have to be const, because a non-const implicit
+object parameter may be bound to an rvalue [13.3.3.1.4/3]
+[13.3.1/5]. </p>
+
+ <p>Tokyo: The LWG removed the following from the proposed resolution:</p>
+
+ <p>In 20.4.5 , paragraph 2, and 20.4.5.3 ,
+ paragraph 2, make the conversion to auto_ptr_ref const:</p>
+ <blockquote>
+ <pre>template<class Y> operator auto_ptr_ref<Y>() const throw();</pre>
+ </blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>In 20.4.5 , paragraph 2, move
+the <tt>auto_ptr_ref</tt> definition to namespace scope.</p>
+
+<p>In 20.4.5 , paragraph 2, add
+a public assignment operator to the <tt>auto_ptr</tt> definition: </p>
+
+<blockquote>
+ <pre>auto_ptr& operator=(auto_ptr_ref<X> r) throw();</pre>
+</blockquote>
+
+<p>Also add the assignment operator to 20.4.5.3 : </p>
+
+<blockquote>
+ <pre>auto_ptr& operator=(auto_ptr_ref<X> r) throw()</pre>
+
+ <b>Effects:</b> Calls <tt>reset(p.release())</tt> for the <tt>auto_ptr
+ p</tt> that <tt>r</tt> holds a reference to.<br>
+ <b>Returns: </b><tt>*this</tt>.
+
+</blockquote>
+<hr>
+<a name="129"><h3>129. Need error indication from seekp() and seekg()</h3></a><p>
+<b>Section:</b> 27.6.1.3 <a href="lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>, 27.6.2.4 <a href="lib-iostreams.html#lib.ostream.seeks"> [lib.ostream.seeks]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> 22 Feb 1999</p>
+<p>Currently, the standard does not specify how seekg() and seekp()
+indicate failure. They are not required to set failbit, and they can't
+return an error indication because they must return *this, i.e. the
+stream. Hence, it is undefined what happens if they fail. And they
+<i>can</i> fail, for instance, when a file stream is disconnected from the
+underlying file (is_open()==false) or when a wide character file
+stream must perform a state-dependent code conversion, etc. </p>
+
+<p>The stream functions seekg() and seekp() should set failbit in the
+stream state in case of failure.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add to the Effects: clause of seekg() in
+27.6.1.3 and to the Effects: clause of seekp() in
+27.6.2.4 : </p>
+
+<blockquote>
+ <p>In case of failure, the function calls <tt>setstate(failbit)</tt> (which may throw <tt>ios_base::failure</tt>).
+ </p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Setting failbit is the usual error reporting mechanism for streams</p>
+<hr>
+<a name="132"><h3>132. list::resize description uses random access iterators</h3></a><p>
+<b>Section:</b> 23.2.2.2 <a href="lib-containers.html#lib.list.capacity"> [lib.list.capacity]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 6 Mar 1999</p>
+<p>The description reads:</p>
+
+<p>-1- Effects:</p>
+
+<pre> if (sz > size())
+ insert(end(), sz-size(), c);
+ else if (sz < size())
+ erase(begin()+sz, end());
+ else
+ ; // do nothing</pre>
+
+<p>Obviously list::resize should not be specified in terms of random access iterators.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 23.2.2.2 paragraph 1 to:</p>
+
+<p>Effects:</p>
+
+<pre> if (sz > size())
+ insert(end(), sz-size(), c);
+ else if (sz < size())
+ {
+ iterator i = begin();
+ advance(i, sz);
+ erase(i, end());
+ }</pre>
+
+<p><i>[Dublin: The LWG asked Howard to discuss exception safety offline
+with David Abrahams. They had a discussion and believe there is
+no issue of exception safety with the proposed resolution.]</i></p>
+<hr>
+<a name="133"><h3>133. map missing get_allocator()</h3></a><p>
+<b>Section:</b> 23.3.1 <a href="lib-containers.html#lib.map"> [lib.map]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 6 Mar 1999</p>
+<p>The title says it all.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Insert in 23.3.1 , paragraph 2,
+after operator= in the map declaration:</p>
+
+<pre> allocator_type get_allocator() const;</pre>
+<hr>
+<a name="134"><h3>134. vector constructors over specified</h3></a><p>
+<b>Section:</b> 23.2.4.1 <a href="lib-containers.html#lib.vector.cons"> [lib.vector.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 6 Mar 1999</p>
+<p>The complexity description says: "It does at most 2N calls to the copy constructor
+of T and logN reallocations if they are just input iterators ...".</p>
+
+<p>This appears to be overly restrictive, dictating the precise memory/performance
+tradeoff for the implementor.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 23.2.4.1 , paragraph 1 to:</p>
+
+<p>-1- Complexity: The constructor template <class
+InputIterator> vector(InputIterator first, InputIterator last)
+makes only N calls to the copy constructor of T (where N is the
+distance between first and last) and no reallocations if iterators
+first and last are of forward, bidirectional, or random access
+categories. It makes order N calls to the copy constructor of T and
+order logN reallocations if they are just input iterators.
+</p>
+<p><b>Rationale:</b></p>
+<p>"at most 2N calls" is correct only if the growth factor
+is greater than or equal to 2.
+</p>
+<hr>
+<a name="136"><h3>136. seekp, seekg setting wrong streams?</h3></a><p>
+<b>Section:</b> 27.6.1.3 <a href="lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 6 Mar 1999</p>
+<p>I may be misunderstanding the intent, but should not seekg set only
+the input stream and seekp set only the output stream? The description
+seems to say that each should set both input and output streams. If
+that's really the intent, I withdraw this proposal.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In section 27.6.1.3 change:</p>
+
+<pre>basic_istream<charT,traits>& seekg(pos_type pos);
+Effects: If fail() != true, executes rdbuf()->pubseekpos(pos). </pre>
+
+<p>To:</p>
+
+<pre>basic_istream<charT,traits>& seekg(pos_type pos);
+Effects: If fail() != true, executes rdbuf()->pubseekpos(pos, ios_base::in). </pre>
+
+<p>In section 27.6.1.3 change:</p>
+
+<pre>basic_istream<charT,traits>& seekg(off_type& off, ios_base::seekdir dir);
+Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir). </pre>
+
+<p>To:</p>
+
+<pre>basic_istream<charT,traits>& seekg(off_type& off, ios_base::seekdir dir);
+Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir, ios_base::in). </pre>
+
+<p>In section 27.6.2.4, paragraph 2 change:</p>
+
+<pre>-2- Effects: If fail() != true, executes rdbuf()->pubseekpos(pos). </pre>
+
+<p>To:</p>
+
+<pre>-2- Effects: If fail() != true, executes rdbuf()->pubseekpos(pos, ios_base::out). </pre>
+
+<p>In section 27.6.2.4, paragraph 4 change:</p>
+
+<pre>-4- Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir). </pre>
+
+<p>To:</p>
+
+<pre>-4- Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir, ios_base::out). </pre>
+
+<p><i>[Dublin: Dietmar Kühl thinks this is probably correct, but would
+like the opinion of more iostream experts before taking action.]</i></p>
+
+<p><i>[Tokyo: Reviewed by the LWG. PJP noted that although his docs are
+incorrect, his implementation already implements the Proposed
+Resolution.]</i></p>
+
+<p><i>[Post-Tokyo: Matt Austern comments:<br>
+Is it a problem with basic_istream and basic_ostream, or is it a problem
+with basic_stringbuf?
+We could resolve the issue either by changing basic_istream and
+basic_ostream, or by changing basic_stringbuf. I prefer the latter
+change (or maybe both changes): I don't see any reason for the standard to
+require that std::stringbuf s(std::string("foo"), std::ios_base::in);
+s.pubseekoff(0, std::ios_base::beg); must fail.<br>
+This requirement is a bit weird. There's no similar requirement
+for basic_streambuf<>::seekpos, or for basic_filebuf<>::seekoff or
+basic_filebuf<>::seekpos.]</i></p>
+<hr>
+<a name="137"><h3>137. Do use_facet and has_facet look in the global locale?</h3></a><p>
+<b>Section:</b> 22.1.1 <a href="lib-locales.html#lib.locale"> [lib.locale]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> 17 Mar 1999</p>
+<p>Section 22.1.1 says:</p>
+
+<p>-4- In the call to use_facet<Facet>(loc), the type argument
+chooses a facet, making available all members of the named type. If
+Facet is not present in a locale (or, failing that, in the global
+locale), it throws the standard exception bad_cast. A C++ program can
+check if a locale implements a particular facet with the template
+function has_facet<Facet>(). </p>
+
+<p>This contradicts the specification given in section
+22.1.2 :
+<br><br>
+template <class Facet> const Facet& use_facet(const
+locale& loc); <br>
+<br>
+-1- Get a reference to a facet of a locale. <br>
+-2- Returns: a reference to the corresponding facet of loc, if present. <br>
+-3- Throws: bad_cast if has_facet<Facet>(loc) is false. <br>
+-4- Notes: The reference returned remains valid at least as long as any copy of loc exists
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove the phrase "(or, failing that, in the global locale)"
+from section 22.1.1. </p>
+<p><b>Rationale:</b></p>
+<p>Needed for consistency with the way locales are handled elsewhere
+in the standard.</p>
+<hr>
+<a name="139"><h3>139. Optional sequence operation table description unclear</h3></a><p>
+<b>Section:</b> 23.1.1 <a href="lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 30 Mar 1999</p>
+<p>The sentence introducing the Optional sequence operation table
+(23.1.1 paragraph 12) has two problems:</p>
+
+<p>A. It says ``The operations in table 68 are provided only for the containers for which
+they take constant time.''<br>
+<br>
+That could be interpreted in two ways, one of them being ``Even though table 68 shows
+particular operations as being provided, implementations are free to omit them if they
+cannot implement them in constant time.''<br>
+<br>
+B. That paragraph says nothing about amortized constant time, and it should. </p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace the wording in 23.1.1 paragraph 12 which begins ``The operations in table 68 are provided only..."
+with:</p>
+
+<blockquote>
+ <p>Table 68 lists sequence operations that are provided for some types of sequential
+ containers but not others. An implementation shall provide these operations for all
+ container types shown in the ``container'' column, and shall implement them so as to take
+ amortized constant time.</p>
+</blockquote>
+<hr>
+<a name="141"><h3>141. basic_string::find_last_of, find_last_not_of say pos instead of xpos</h3></a><p>
+<b>Section:</b> 21.3.6.4 <a href="lib-strings.html#lib.string::find.last.of"> [lib.string::find.last.of]</a>, 21.3.6.6 <a href="lib-strings.html#lib.string::find.last.not.of"> [lib.string::find.last.not.of]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Arch Robison <b>Date:</b> 28 Apr 1999</p>
+<p>Sections 21.3.6.4 paragraph 1 and 21.3.6.6 paragraph 1 surely have misprints where they
+say:<br>
+<br>
+— <tt>xpos <= pos</tt> and <tt>pos < size();</tt>
+</p>
+
+<p>Surely the document meant to say ``<tt>xpos < size()</tt>'' in both places.</p>
+
+<p><i>[Judy Ward also sent in this issue for 21.3.6.4 with the same
+proposed resolution.]</i></p>
+<p><b>Proposed resolution:</b></p>
+<p>Change Sections 21.3.6.4 paragraph 1 and 21.3.6.6 paragraph 1, the line which says:<br>
+<br>
+— <tt>xpos <= pos</tt> and <tt>pos < size();<br>
+<br>
+</tt>to:<br>
+<tt><br>
+</tt>— <tt>xpos <= pos</tt> and <tt>xpos < size();</tt>
+</p>
+<hr>
+<a name="142"><h3>142. lexicographical_compare complexity wrong</h3></a><p>
+<b>Section:</b> 25.3.8 <a href="lib-algorithms.html#lib.alg.lex.comparison"> [lib.alg.lex.comparison]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Howard Hinnant <b>Date:</b> 20 Jun 1999</p>
+<p>The lexicographical_compare complexity is specified as:<br>
+<br>
+ "At most min((last1 - first1), (last2 - first2))
+applications of the corresponding comparison."<br>
+<br>
+The best I can do is twice that expensive.</p>
+
+<p>Nicolai Josuttis comments in lib-6862: You mean, to check for
+equality you have to check both < and >? Yes, IMO you are
+right! (and Matt states this complexity in his book)</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Change 25.3.8 complexity to:</p>
+ <blockquote>
+ At most <tt>2*min((last1 - first1), (last2 - first2))</tt>
+ applications of the corresponding comparison.
+ </blockquote>
+
+<p>Change the example at the end of paragraph 3 to read:</p>
+ <blockquote>
+ [Example:<br>
+ <br>
+ for ( ; first1 != last1 && first2 != last2 ;
+ ++first1, ++first2) {<br>
+ if (*first1 < *first2) return true;<br>
+ if (*first2 < *first1) return false;<br>
+ }<br>
+ return first1 == last1 && first2 != last2;<br>
+ <br>
+ --end example]
+ </blockquote>
+<hr>
+<a name="144"><h3>144. Deque constructor complexity wrong </h3></a><p>
+<b>Section:</b> 23.2.1.1 <a href="lib-containers.html#lib.deque.cons"> [lib.deque.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Herb Sutter <b>Date:</b> 9 May 1999</p>
+<p>In 23.2.1.1 paragraph 6, the deque ctor that takes an iterator range appears
+to have complexity requirements which are incorrect, and which contradict the
+complexity requirements for insert(). I suspect that the text in question,
+below, was taken from vector:</p>
+<blockquote>
+ <p>Complexity: If the iterators first and last are forward iterators,
+ bidirectional iterators, or random access iterators the constructor makes only
+ N calls to the copy constructor, and performs no reallocations, where N is
+ last - first.</p>
+</blockquote>
+<p>The word "reallocations" does not really apply to deque. Further,
+all of the following appears to be spurious:</p>
+<blockquote>
+ <p>It makes at most 2N calls to the copy constructor of T and log N
+ reallocations if they are input iterators.1)</p>
+ <p>1) The complexity is greater in the case of input iterators because each
+ element must be added individually: it is impossible to determine the distance
+ between first abd last before doing the copying.</p>
+</blockquote>
+<p>This makes perfect sense for vector, but not for deque. Why should deque gain
+an efficiency advantage from knowing in advance the number of elements to
+insert?</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 23.2.1.1 paragraph 6, replace the Complexity description, including the
+footnote, with the following text (which also corrects the "abd"
+typo):</p>
+<blockquote>
+ <p>Complexity: Makes last - first calls to the copy constructor of T.</p>
+</blockquote>
+<hr>
+<a name="146"><h3>146. complex<T> Inserter and Extractor need sentries</h3></a><p>
+<b>Section:</b> 26.2.6 <a href="lib-numerics.html#lib.complex.ops"> [lib.complex.ops]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> 12 May 1999</p>
+<p>The <u> extractor</u> for complex numbers is specified as: </p>
+
+<blockquote>
+
+<p> template<class T, class charT, class traits> <br>
+ basic_istream<charT, traits>& <br>
+ operator>>(basic_istream<charT, traits>& is, complex<T>& x);<br>
+ <br>
+Effects: Extracts a complex number x of the form: u, (u), or (u,v),
+where u is the real part and v is the imaginary part
+(lib.istream.formatted). <br>
+Requires: The input values be convertible to T. If bad input is
+encountered, calls is.setstate(ios::failbit) (which may throw
+ios::failure (lib.iostate.flags). <br>
+Returns: is .</p>
+
+</blockquote>
+<p>Is it intended that the extractor for complex numbers does not skip
+whitespace, unlike all other extractors in the standard library do?
+Shouldn't a sentry be used? <br>
+<br>
+The <u>inserter</u> for complex numbers is specified as:</p>
+
+<blockquote>
+
+<p> template<class T, class charT, class traits> <br>
+ basic_ostream<charT, traits>& <br>
+ operator<<(basic_ostream<charT, traits>& o, const complex<T>& x);<br>
+<br>
+Effects: inserts the complex number x onto the stream o as if it were implemented as follows:<br>
+<br>
+ template<class T, class charT, class traits> <br>
+ basic_ostream<charT, traits>& <br>
+ operator<<(basic_ostream<charT, traits>& o, const complex<T>& x) <br>
+ { <br>
+ basic_ostringstream<charT, traits> s; <br>
+ s.flags(o.flags()); <br>
+ s.imbue(o.getloc()); <br>
+ s.precision(o.precision()); <br>
+ s << '(' << x.real() << "," << x.imag() << ')'; <br>
+ return o << s.str(); <br>
+ }</p>
+
+</blockquote>
+
+<p>Is it intended that the inserter for complex numbers ignores the
+field width and does not do any padding? If, with the suggested
+implementation above, the field width were set in the stream then the
+opening parentheses would be adjusted, but the rest not, because the
+field width is reset to zero after each insertion.</p>
+
+<p>I think that both operations should use sentries, for sake of
+consistency with the other inserters and extractors in the
+library. Regarding the issue of padding in the inserter, I don't know
+what the intent was. </p>
+<p><b>Proposed resolution:</b></p>
+<p>After 26.2.6 paragraph 14 (operator>>), add a
+Notes clause:</p>
+
+<blockquote>
+
+<p>Notes: This extraction is performed as a series of simpler
+extractions. Therefore, the skipping of whitespace is specified to be the
+same for each of the simpler extractions.</p>
+
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>For extractors, the note is added to make it clear that skipping whitespace
+follows an "all-or-none" rule.</p>
+
+<p>For inserters, the LWG believes there is no defect; the standard is correct
+as written.</p>
+<hr>
+<a name="147"><h3>147. Library Intro refers to global functions that aren't global</h3></a><p>
+<b>Section:</b> 17.4.4.3 <a href="lib-intro.html#lib.global.functions"> [lib.global.functions]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Lois Goldthwaite <b>Date:</b> 4 Jun 1999</p>
+<p>The library had many global functions until 17.4.1.1 [lib.contents]
+paragraph 2 was added: </p>
+
+<blockquote>
+
+<p>All library entities except macros, operator new and operator
+delete are defined within the namespace std or namespaces nested
+within namespace std. </p>
+
+</blockquote>
+
+<p>It appears "global function" was never updated in the following: </p>
+
+<blockquote>
+
+<p>17.4.4.3 - Global functions [lib.global.functions]<br>
+<br>
+-1- It is unspecified whether any global functions in the C++ Standard
+Library are defined as inline (dcl.fct.spec).<br>
+<br>
+-2- A call to a global function signature described in Clauses
+lib.language.support through lib.input.output behaves the same as if
+the implementation declares no additional global function
+signatures.*<br>
+<br>
+ [Footnote: A valid C++ program always calls the expected library
+ global function. An implementation may also define additional
+ global functions that would otherwise not be called by a valid C++
+ program. --- end footnote]<br>
+<br>
+-3- A global function cannot be declared by the implementation as
+taking additional default arguments. <br>
+<br>
+17.4.4.4 - Member functions [lib.member.functions]<br>
+<br>
+-2- An implementation can declare additional non-virtual member
+function signatures within a class: </p>
+
+ <blockquote>
+
+<p>-- by adding arguments with default values to a member function
+signature; The same latitude does not extend to the implementation of
+virtual or global functions, however. </p>
+
+ </blockquote>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p> Change "global" to "global or non-member" in:</p>
+<blockquote>
+ <p>17.4.4.3 [lib.global.functions] section title,<br>
+ 17.4.4.3 [lib.global.functions] para 1,<br>
+ 17.4.4.3 [lib.global.functions] para 2 in 2 places plus 2
+ places in the footnote,<br>
+ 17.4.4.3 [lib.global.functions] para 3,<br>
+ 17.4.4.4 [lib.member.functions] para 2</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>
+Because operator new and delete are global, the proposed resolution
+was changed from "non-member" to "global or non-member.
+</p>
+<hr>
+<a name="148"><h3>148. Functions in the example facet BoolNames should be const</h3></a><p>
+<b>Section:</b> 22.2.8 <a href="lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Jeremy Siek <b>Date:</b> 3 Jun 1999</p>
+<p>In 22.2.8 paragraph 13, the do_truename() and
+do_falsename() functions in the example facet BoolNames should be
+const. The functions they are overriding in
+numpunct_byname<char> are const. </p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.8 paragraph 13, insert "const" in
+two places:</p>
+<blockquote>
+ <p><tt>string do_truename() const { return "Oui Oui!"; }<br>
+ string do_falsename() const { return "Mais Non!"; }</tt></p>
+</blockquote>
+<hr>
+<a name="150"><h3>150. Find_first_of says integer instead of iterator </h3></a><p>
+<b>Section:</b> 25.1.4 <a href="lib-algorithms.html#lib.alg.find.first.of"> [lib.alg.find.first.of]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt McClure <b>Date:</b> 30 Jun 1999</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 25.1.4 paragraph 2 from:</p>
+
+<blockquote>
+<p>Returns: The first iterator i in the range [first1, last1) such
+that for some <u>integer</u> j in the range [first2, last2) ...</p>
+</blockquote>
+
+<p>to:</p>
+
+<blockquote>
+<p>Returns: The first iterator i in the range [first1, last1) such
+that for some iterator j in the range [first2, last2) ...</p>
+</blockquote>
+<hr>
+<a name="151"><h3>151. Can't currently clear() empty container</h3></a><p>
+<b>Section:</b> 23.1.1 <a href="lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Ed Brey <b>Date:</b> 21 Jun 1999</p>
+<p>For both sequences and associative containers, a.clear() has the
+semantics of erase(a.begin(),a.end()), which is undefined for an empty
+container since erase(q1,q2) requires that q1 be dereferenceable
+(23.1.1,3 and 23.1.2,7). When the container is empty, a.begin() is
+not dereferenceable.<br>
+<br>
+The requirement that q1 be unconditionally dereferenceable causes many
+operations to be intuitively undefined, of which clearing an empty
+container is probably the most dire.<br>
+<br>
+Since q1 and q2 are only referenced in the range [q1, q2), and [q1,
+q2) is required to be a valid range, stating that q1 and q2 must be
+iterators or certain kinds of iterators is unnecessary.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 23.1.1, paragraph 3, change:</p>
+<blockquote>
+ <p>p and q2 denote valid iterators to a, q <u> and q1</u> denote valid dereferenceable iterators to a, [q1, q2) denotes a valid range</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>p denotes a valid iterator to a, q denotes a valid dereferenceable iterator to a, [q1, q2) denotes a valid range<u>
+ in a</u>
+</p>
+</blockquote>
+<p>In 23.1.2, paragraph 7, change:</p>
+<blockquote>
+ <p>p and q2 are valid iterators to a, q <u> and q1</u> are valid dereferenceable
+ iterators to a, [q1, q2) is a valid range</p>
+</blockquote>
+<p>to</p>
+<blockquote>
+ <p>p is a valid iterator to a, q is a valid dereferenceable iterator to a, [q1, q2) is a valid range
+ <u>into a</u>
+</p>
+</blockquote>
+<hr>
+<a name="152"><h3>152. Typo in <tt>scan_is()</tt> semantics</h3></a><p>
+<b>Section:</b> 22.2.1.1.2 <a href="lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The semantics of <tt>scan_is()</tt> (paragraphs 4 and 6) is not exactly described
+because there is no function <tt>is()</tt> which only takes a character as
+argument. Also, in the effects clause (paragraph 3), the semantic is also kept
+vague.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.1.1.2 paragraphs 4 and 6, change the returns
+clause from:</p>
+<blockquote>
+ <p>"... such that <tt>is(*p)</tt>
+would..."</p>
+</blockquote>
+<p>to: "... such that <tt>is(m, *p)</tt>
+ would...."</p>
+<hr>
+<a name="153"><h3>153. Typo in <tt>narrow()</tt> semantics</h3></a><p>
+<b>Section:</b> 22.2.1.3.2 <a href="lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The description of the array version of <tt>narrow()</tt> (in
+paragraph 11) is flawed: There is no member <tt>do_narrow()</tt> which
+takes only three arguments because in addition to the range a default
+character is needed.</p>
+
+<p>Additionally, for both <tt>widen</tt> and <tt>narrow</tt> we have
+two signatures followed by a <b>Returns</b> clause that only addresses
+one of them.</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>Change the returns clause in 22.2.1.3.2
+paragraph 10 from:</p>
+<p> Returns: do_widen(low, high, to).</p>
+
+<p>to:</p>
+<p> Returns: do_widen(c) or do_widen(low, high, to),
+respectively.</p>
+
+<p>Change 22.2.1.3.2 paragraph 10 and 11 from:</p>
+<pre> char narrow(char c, char /*dfault*/) const;
+ const char* narrow(const char* low, const char* high,
+ char /*dfault*/, char* to) const;</pre>
+<pre> Returns: do_narrow(low, high, to).</pre>
+<p>to:</p>
+<pre> char narrow(char c, char dfault) const;
+ const char* narrow(const char* low, const char* high,
+ char dfault, char* to) const;</pre>
+<pre> Returns: do_narrow(c, dfault) or
+ do_narrow(low, high, dfault, to), respectively.</pre>
+
+<p><i>[Kona: 1) the problem occurs in additional places, 2) a user
+defined version could be different.]</i></p>
+
+<p><i>[Post-Tokyo: Dietmar provided the above wording at the request of
+the LWG. He could find no other places the problem occurred. He
+asks for clarification of the Kona "a user defined
+version..." comment above. Perhaps it was a circuitous way of
+saying "dfault" needed to be uncommented?]</i></p>
+
+<p><i>[Post-Toronto: the issues list maintainer has merged in the
+proposed resolution from issue <a href="lwg-closed.html#207">207</a>, which addresses the
+same paragraphs.]</i></p>
+<hr>
+<a name="154"><h3>154. Missing <tt>double</tt> specifier for <tt>do_get()</tt>
+</h3></a><p>
+<b>Section:</b> 22.2.2.1.2 <a href="lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The table in paragraph 7 for the length modifier does not list the length
+modifier <tt>l</tt> to be applied if the type is <tt>double</tt>. Thus, the
+standard asks the implementation to do undefined things when using <tt>scanf()</tt>
+(the missing length modifier for <tt>scanf()</tt> when scanning <tt>double</tt>s
+is actually a problem I found quite often in production code, too).</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.2.1.2 , paragraph 7, add a row in the Length
+Modifier table to say that for <tt>double</tt> a length modifier
+<tt>l</tt> is to be used.</p>
+<p><b>Rationale:</b></p>
+<p>The standard makes an embarrassing beginner's mistake.</p>
+<hr>
+<a name="155"><h3>155. Typo in naming the class defining the class <tt>Init</tt>
+</h3></a><p>
+<b>Section:</b> 27.3 <a href="lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>There are conflicting statements about where the class
+<tt>Init</tt> is defined. According to 27.3 paragraph 2
+it is defined as <tt>basic_ios::Init</tt>, according to 27.4.2 it is defined as <tt>ios_base::Init</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.3 paragraph 2 from
+"<tt>basic_ios::Init"</tt> to
+"<tt>ios_base::Init"</tt>.</p>
+<p><b>Rationale:</b></p>
+<p>Although not strictly wrong, the standard was misleading enough to warrant
+the change.</p>
+<hr>
+<a name="156"><h3>156. Typo in <tt>imbue()</tt> description</h3></a><p>
+<b>Section:</b> 27.4.2.3 <a href="lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>There is a small discrepancy between the declarations of
+<tt>imbue()</tt>: in 27.4.2 the argument is passed as
+<tt>locale const&</tt> (correct), in 27.4.2.3 it
+is passed as <tt>locale const</tt> (wrong).</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.4.2.3 change the <tt>imbue</tt> argument
+from "<tt>locale const" to "locale
+const&".</tt>
+</p>
+<hr>
+<a name="158"><h3>158. Underspecified semantics for <tt>setbuf()</tt>
+</h3></a><p>
+<b>Section:</b> 27.5.2.4.2 <a href="lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The default behavior of <tt>setbuf()</tt> is described only for the
+situation that <tt>gptr() != 0 && gptr() != egptr()</tt>:
+namely to do nothing. What has to be done in other situations
+is not described although there is actually only one reasonable
+approach, namely to do nothing, too.</p>
+
+<p>Since changing the buffer would almost certainly mess up most
+buffer management of derived classes unless these classes do it
+themselves, the default behavior of <tt>setbuf()</tt> should always be
+to do nothing.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.5.2.4.2 , paragraph 3, Default behavior,
+to: "Default behavior: Does nothing. Returns this."</p>
+<hr>
+<a name="159"><h3>159. Strange use of <tt>underflow()</tt>
+</h3></a><p>
+<b>Section:</b> 27.5.2.4.3 <a href="lib-iostreams.html#lib.streambuf.virt.get"> [lib.streambuf.virt.get]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The description of the meaning of the result of
+<tt>showmanyc()</tt> seems to be rather strange: It uses calls to
+<tt>underflow()</tt>. Using <tt>underflow()</tt> is strange because
+this function only reads the current character but does not extract
+it, <tt>uflow()</tt> would extract the current character. This should
+be fixed to use <tt>sbumpc()</tt> instead.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.5.2.4.3 paragraph 1,
+<tt>showmanyc()</tt>returns clause, by replacing the word
+"supplied" with the words "extracted from the
+stream".</p>
+<hr>
+<a name="160"><h3>160. Typo: Use of non-existing function <tt>exception()</tt>
+</h3></a><p>
+<b>Section:</b> 27.6.1.1 <a href="lib-iostreams.html#lib.istream"> [lib.istream]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The paragraph 4 refers to the function <tt>exception()</tt> which
+is not defined. Probably, the referred function is
+<tt>basic_ios<>::exceptions()</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.6.1.1 , 27.6.1.3 , paragraph 1,
+27.6.2.1 , paragraph 3, and 27.6.2.5.1 ,
+paragraph 1, change "<tt>exception()" to
+"exceptions()"</tt>.</p>
+
+<p><i>[Note to Editor: "exceptions" with an "s"
+is the correct spelling.]</i></p>
+<hr>
+<a name="161"><h3>161. Typo: <tt>istream_iterator</tt> vs. <tt>istreambuf_iterator</tt>
+</h3></a><p>
+<b>Section:</b> 27.6.1.2.2 <a href="lib-iostreams.html#lib.istream.formatted.arithmetic"> [lib.istream.formatted.arithmetic]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The note in the second paragraph pretends that the first argument
+is an object of type <tt>istream_iterator</tt>. This is wrong: It is
+an object of type <tt>istreambuf_iterator</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 27.6.1.2.2 from:</p>
+<blockquote>
+ <p>The first argument provides an object of the istream_iterator class...</p>
+</blockquote>
+<p>to</p>
+<blockquote>
+ <p>The first argument provides an object of the istreambuf_iterator class...</p>
+</blockquote>
+<hr>
+<a name="164"><h3>164. do_put() has apparently unused fill argument</h3></a><p>
+<b>Section:</b> 22.2.5.3.2 <a href="lib-locales.html#lib.locale.time.put.virtuals"> [lib.locale.time.put.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Angelika Langer <b>Date:</b> 23 Jul 1999</p>
+<p>In 22.2.5.3.2 the do_put() function is specified
+as taking a fill character as an argument, but the description of the
+function does not say whether the character is used at all and, if so,
+in which way. The same holds for any format control parameters that
+are accessible through the ios_base& argument, such as the
+adjustment or the field width. Is strftime() supposed to use the fill
+character in any way? In any case, the specification of
+time_put.do_put() looks inconsistent to me.<br> <br> Is the
+signature of do_put() wrong, or is the effects clause incomplete?</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the following note after 22.2.5.3.2
+paragraph 2:</p>
+<blockquote>
+ <p> [Note: the <tt>fill</tt> argument may be used in the implementation-defined formats, or by derivations. A space character is a reasonable default
+ for this argument. --end Note]</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The LWG felt that while the normative text was correct,
+users need some guidance on what to pass for the <tt>fill</tt>
+argument since the standard doesn't say how it's used.</p>
+<hr>
+<a name="165"><h3>165. <tt>xsputn()</tt>, <tt>pubsync()</tt> never called by <tt>basic_ostream</tt> members?</h3></a><p>
+<b>Section:</b> 27.6.2.1 <a href="lib-iostreams.html#lib.ostream"> [lib.ostream]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>Paragraph 2 explicitly states that none of the <tt>basic_ostream</tt>
+functions falling into one of the groups "formatted output functions"
+and "unformatted output functions" calls any stream buffer function
+which might call a virtual function other than <tt>overflow()</tt>. Basically
+this is fine but this implies that <tt>sputn()</tt> (this function would call
+the virtual function <tt>xsputn()</tt>) is never called by any of the standard
+output functions. Is this really intended? At minimum it would be convenient to
+call <tt>xsputn()</tt> for strings... Also, the statement that <tt>overflow()</tt>
+is the only virtual member of <tt>basic_streambuf</tt> called is in conflict
+with the definition of <tt>flush()</tt> which calls <tt>rdbuf()->pubsync()</tt>
+and thereby the virtual function <tt>sync()</tt> (<tt>flush()</tt> is listed
+under "unformatted output functions").</p>
+<p>In addition, I guess that the sentence starting with "They may use other
+public members of <tt>basic_ostream</tt> ..." probably was intended to
+start with "They may use other public members of <tt>basic_streamuf</tt>..."
+although the problem with the virtual members exists in both cases.</p>
+<p>I see two obvious resolutions:</p>
+<ol>
+ <li>state in a footnote that this means that <tt>xsputn()</tt> will never be
+ called by any ostream member and that this is intended.</li>
+ <li>relax the restriction and allow calling <tt>overflow()</tt> and <tt>xsputn()</tt>.
+ Of course, the problem with <tt>flush()</tt> has to be resolved in some way.</li>
+</ol>
+<p><b>Proposed resolution:</b></p>
+<p>Change the last sentence of 27.6.2.1 (lib.ostream) paragraph 2 from:</p>
+<blockquote>
+ <p>They may use other public members of basic_ostream except that they do not
+ invoke any virtual members of rdbuf() except overflow().</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>They may use other public members of basic_ostream except that they shall
+ not invoke any virtual members of rdbuf() except overflow(), xsputn(), and
+ sync().</p>
+</blockquote>
+
+<p><i>[Kona: the LWG believes this is a problem. Wish to ask Jerry or
+PJP why the standard is written this way.]</i></p>
+
+<p><i>[Post-Tokyo: Dietmar supplied wording at the request of the
+LWG. He comments: The rules can be made a little bit more specific if
+necessary be explicitly spelling out what virtuals are allowed to be
+called from what functions and eg to state specifically that flush()
+is allowed to call sync() while other functions are not.]</i></p>
+<hr>
+<a name="168"><h3>168. Typo: formatted vs. unformatted</h3></a><p>
+<b>Section:</b> 27.6.2.6 <a href="lib-iostreams.html#lib.ostream.unformatted"> [lib.ostream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The first paragraph begins with a descriptions what has to be done
+in <i>formatted</i> output functions. Probably this is a typo and the
+paragraph really want to describe unformatted output functions...</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.6.2.6 paragraph 1, the first and last
+sentences, change the word "formatted" to
+"unformatted":</p>
+<blockquote>
+ <p>"Each <b>unformatted </b> output function begins ..."<br>
+ "... value specified for the <b>unformatted </b> output
+ function."</p>
+</blockquote>
+<hr>
+<a name="169"><h3>169. Bad efficiency of <tt>overflow()</tt> mandated</h3></a><p>
+<b>Section:</b> 27.7.1.3 <a href="lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>Paragraph 8, Notes, of this section seems to mandate an extremely
+inefficient way of buffer handling for <tt>basic_stringbuf</tt>,
+especially in view of the restriction that <tt>basic_ostream</tt>
+member functions are not allowed to use <tt>xsputn()</tt> (see 27.6.2.1 ): For each character to be inserted, a new buffer
+is to be created.</p>
+<p>Of course, the resolution below requires some handling of
+simultaneous input and output since it is no longer possible to update
+<tt>egptr()</tt> whenever <tt>epptr()</tt> is changed. A possible
+solution is to handle this in <tt>underflow()</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.7.1.3 paragraph 8, Notes, insert the words
+"at least" as in the following:</p>
+<blockquote>
+ <p>To make a write position available, the function reallocates (or initially
+ allocates) an array object with a sufficient number of elements to hold the
+ current array object (if any), plus <b>at least</b> one additional write
+ position.</p>
+</blockquote>
+<hr>
+<a name="170"><h3>170. Inconsistent definition of <tt>traits_type</tt>
+</h3></a><p>
+<b>Section:</b> 27.7.4 <a href="lib-iostreams.html#lib.stringstream"> [lib.stringstream]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>The classes <tt>basic_stringstream</tt> (27.7.4 ),
+<tt>basic_istringstream</tt> (27.7.2 ), and
+<tt>basic_ostringstream</tt> (27.7.3 ) are inconsistent
+in their definition of the type <tt>traits_type</tt>: For
+<tt>istringstream</tt>, this type is defined, for the other two it is
+not. This should be consistent.</p>
+<p><b>Proposed resolution:</b></p>
+<p><b>Proposed resolution:</b></p> <p>To the declarations of
+<tt>basic_ostringstream</tt> (27.7.3 ) and
+<tt>basic_stringstream</tt> (27.7.4 ) add:</p>
+<blockquote>
+<pre>typedef traits traits_type;</pre>
+</blockquote>
+<hr>
+<a name="171"><h3>171. Strange <tt>seekpos()</tt> semantics due to joint position</h3></a><p>
+<b>Section:</b> 27.8.1.4 <a href="lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 20 Jul 1999</p>
+<p>Overridden virtual functions, seekpos()</p> <p>In 27.8.1.1 paragraph 3, it is stated that a joint input and
+output position is maintained by <tt>basic_filebuf</tt>. Still, the
+description of <tt>seekpos()</tt> seems to talk about different file
+positions. In particular, it is unclear (at least to me) what is
+supposed to happen to the output buffer (if there is one) if only the
+input position is changed. The standard seems to mandate that the
+output buffer is kept and processed as if there was no positioning of
+the output position (by changing the input position). Of course, this
+can be exactly what you want if the flag <tt>ios_base::ate</tt> is
+set. However, I think, the standard should say something like
+this:</p>
+<ul>
+ <li>If <tt>(which & mode) == 0</tt> neither read nor write position is
+ changed and the call fails. Otherwise, the joint read and write position is
+ altered to correspond to <tt>sp</tt>.</li>
+ <li>If there is an output buffer, the output sequences is updated and any
+ unshift sequence is written before the position is altered.</li>
+ <li>If there is an input buffer, the input sequence is updated after the
+ position is altered.</li>
+</ul>
+<p>Plus the appropriate error handling, that is...</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the unnumbered paragraph in 27.8.1.4 (lib.filebuf.virtuals) before
+paragraph 14 from:</p>
+<blockquote>
+ <p>pos_type seekpos(pos_type sp, ios_base::openmode = ios_base::in |
+ ios_base::out);</p>
+ <p>Alters the file position, if possible, to correspond to the position stored
+ in sp (as described below).</p>
+ <p>- if (which&ios_base::in)!=0, set the file position to sp, then update
+ the input sequence</p>
+ <p>- if (which&ios_base::out)!=0, then update the output sequence, write
+ any unshift sequence, and set the file position to sp.</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>pos_type seekpos(pos_type sp, ios_base::openmode = ios_base::in |
+ ios_base::out);</p>
+ <p>Alters the file position, if possible, to correspond to the position stored
+ in sp (as described below). Altering the file position performs as follows:</p>
+ <p>1. if (om & ios_base::out)!=0, then update the output sequence and
+ write any unshift sequence;</p>
+ <p>2. set the file position to sp;</p>
+ <p>3. if (om & ios_base::in)!=0, then update the input sequence;</p>
+ <p>where om is the open mode passed to the last call to open(). The operation
+ fails if is_open() returns false.</p>
+</blockquote>
+
+<p><i>[Kona: Dietmar is working on a proposed resolution.]</i></p>
+<p><i>[Post-Tokyo: Dietmar supplied the above wording.]</i></p>
+<hr>
+<a name="172"><h3>172. Inconsistent types for <tt>basic_istream::ignore()</tt>
+</h3></a><p>
+<b>Section:</b> 27.6.1.3 <a href="lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Greg Comeau, Dietmar Kühl <b>Date:</b> 23 Jul 1999</p>
+<p>In 27.6.1.1 the function
+<tt>ignore()</tt> gets an object of type <tt>streamsize</tt> as first
+argument. However, in 27.6.1.3
+paragraph 23 the first argument is of type <tt>int.</tt>
+</p>
+
+<p>As far as I can see this is not really a contradiction because
+everything is consistent if <tt>streamsize</tt> is typedef to be
+<tt>int</tt>. However, this is almost certainly not what was
+intended. The same thing happened to <tt>basic_filebuf::setbuf()</tt>,
+as described in issue <a href="lwg-defects.html#173">173</a>.</p>
+
+<p>Darin Adler also
+submitted this issue, commenting: Either 27.6.1.1 should be modified
+to show a first parameter of type int, or 27.6.1.3 should be modified
+to show a first parameter of type streamsize and use
+numeric_limits<streamsize>::max.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.6.1.3 paragraph 23 and 24, change both uses
+of <tt>int</tt> in the description of <tt>ignore()</tt> to
+<tt>streamsize</tt>.</p>
+<hr>
+<a name="173"><h3>173. Inconsistent types for <tt>basic_filebuf::setbuf()</tt>
+</h3></a><p>
+<b>Section:</b> 27.8.1.4 <a href="lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Greg Comeau, Dietmar Kühl <b>Date:</b> 23 Jul 1999</p>
+
+<p>
+In 27.8.1.1 the function <tt>setbuf()</tt> gets an
+object of type <tt>streamsize</tt> as second argument. However, in
+27.8.1.4 paragraph 9 the second argument is of type
+<tt>int</tt>.
+</p>
+
+<p>
+As far as I can see this is not really a contradiction because
+everything is consistent if <tt>streamsize</tt> is typedef to be
+<tt>int</tt>. However, this is almost certainly not what was
+intended. The same thing happened to <tt>basic_istream::ignore()</tt>,
+as described in issue <a href="lwg-defects.html#172">172</a>.
+</p>
+
+<p><b>Proposed resolution:</b></p>
+<p>In 27.8.1.4 paragraph 9, change all uses of
+<tt>int</tt> in the description of <tt>setbuf()</tt> to
+<tt>streamsize</tt>.</p>
+<hr>
+<a name="174"><h3>174. Typo: <tt>OFF_T</tt> vs. <tt>POS_T</tt>
+</h3></a><p>
+<b>Section:</b> D.6 <a href="future.html#depr.ios.members"> [depr.ios.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 23 Jul 1999</p>
+<p>According to paragraph 1 of this section, <tt>streampos</tt> is the
+type <tt>OFF_T</tt>, the same type as <tt>streamoff</tt>. However, in
+paragraph 6 the <tt>streampos</tt> gets the type <tt>POS_T</tt>
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change D.6 paragraph 1 from "<tt>typedef
+OFF_T streampos;</tt>" to "<tt>typedef POS_T
+streampos;</tt>"</p>
+<hr>
+<a name="175"><h3>175. Ambiguity for <tt>basic_streambuf::pubseekpos()</tt> and a few other functions.</h3></a><p>
+<b>Section:</b> D.6 <a href="future.html#depr.ios.members"> [depr.ios.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 23 Jul 1999</p>
+<p>According to paragraph 8 of this section, the methods
+<tt>basic_streambuf::pubseekpos()</tt>,
+<tt>basic_ifstream::open()</tt>, and <tt>basic_ofstream::open</tt>
+"may" be overloaded by a version of this function taking the
+type <tt>ios_base::open_mode</tt> as last argument argument instead of
+<tt>ios_base::openmode</tt> (<tt>ios_base::open_mode</tt> is defined
+in this section to be an alias for one of the integral types). The
+clause specifies, that the last argument has a default argument in
+three cases. However, this generates an ambiguity with the overloaded
+version because now the arguments are absolutely identical if the last
+argument is not specified.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In D.6 paragraph 8, remove the default arguments for
+<tt>basic_streambuf::pubseekpos()</tt>,
+<tt>basic_ifstream::open()</tt>, and
+<tt>basic_ofstream::open().</tt>
+</p>
+<hr>
+<a name="176"><h3>176. <tt>exceptions()</tt> in <tt>ios_base</tt>...?</h3></a><p>
+<b>Section:</b> D.6 <a href="future.html#depr.ios.members"> [depr.ios.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 23 Jul 1999</p>
+<p>The "overload" for the function <tt>exceptions()</tt> in
+paragraph 8 gives the impression that there is another function of
+this function defined in class <tt>ios_base</tt>. However, this is not
+the case. Thus, it is hard to tell how the semantics (paragraph 9) can
+be implemented: "Call the corresponding member function specified
+in clause 27 ."</p>
+<p><b>Proposed resolution:</b></p>
+<p>In D.6 paragraph 8, move the declaration of the
+function <tt>exceptions()</tt>into class <tt>basic_ios</tt>.</p>
+<hr>
+<a name="181"><h3>181. make_pair() unintended behavior</h3></a><p>
+<b>Section:</b> 20.2.2 <a href="lib-utilities.html#lib.pairs"> [lib.pairs]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 3 Aug 1999</p>
+<p>The claim has surfaced in Usenet that expressions such as<br>
+<br>
+ <tt>make_pair("abc", 3)</tt><br>
+<br>
+are illegal, notwithstanding their use in examples, because template instantiation tries to bind the first template
+parameter to <tt> const char (&)[4]</tt>, which type is uncopyable.<br>
+<br>
+I doubt anyone intended that behavior...
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 20.2 , paragraph 1 change the following
+declaration of make_pair():</p>
+<blockquote>
+ <pre>template <class T1, class T2> pair<T1,T2> make_pair(const T1&, const T2&);</pre>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <pre>template <class T1, class T2> pair<T1,T2> make_pair(T1, T2);</pre>
+</blockquote>
+<p> In 20.2.2 paragraph 7 and the line before, change:</p>
+<blockquote>
+<pre>template <class T1, class T2>
+pair<T1, T2> make_pair(const T1& x, const T2& y);</pre>
+</blockquote>
+<p>to:</p>
+<blockquote>
+<pre>template <class T1, class T2>
+pair<T1, T2> make_pair(T1 x, T2 y);</pre>
+</blockquote>
+<p>and add the following footnote to the effects clause:</p>
+<blockquote>
+ <p> According to 12.8 [class.copy], an implementation is permitted
+ to not perform a copy of an argument, thus avoiding unnecessary
+ copies.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Two potential fixes were suggested by Matt Austern and Dietmar
+Kühl, respectively, 1) overloading with array arguments, and 2) use of
+a reference_traits class with a specialization for arrays. Andy
+Koenig suggested changing to pass by value. In discussion, it appeared
+that this was a much smaller change to the standard that the other two
+suggestions, and any efficiency concerns were more than offset by the
+advantages of the solution. Two implementors reported that the
+proposed resolution passed their test suites.</p>
+<hr>
+<a name="183"><h3>183. I/O stream manipulators don't work for wide character streams</h3></a><p>
+<b>Section:</b> 27.6.3 <a href="lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Andy Sawyer <b>Date:</b> 7 Jul 1999</p>
+<p>27.6.3 paragraph 3 says (clause numbering added for
+exposition):<a href="lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a>
+</p>
+<blockquote>
+<p>Returns: An object s of unspecified type such that if [1] out is an (instance
+of) basic_ostream then the expression out<<s behaves as if f(s) were
+called, and if [2] in is an (instance of) basic_istream then the expression
+in>>s behaves as if f(s) were called. Where f can be defined as: ios_base&
+f(ios_base& str, ios_base::fmtflags mask) { // reset specified flags
+str.setf(ios_base::fmtflags(0), mask); return str; } [3] The expression
+out<<s has type ostream& and value out. [4] The expression in>>s
+has type istream& and value in.</p>
+</blockquote>
+<p>Given the definitions [1] and [2] for out and in, surely [3] should read:
+"The expression out << s has type basic_ostream& ..." and
+[4] should read: "The expression in >> s has type basic_istream&
+..."</p>
+<p>If the wording in the standard is correct, I can see no way of implementing
+any of the manipulators so that they will work with wide character streams.</p>
+<p>e.g. wcout << setbase( 16 );</p>
+<p>Must have value 'wcout' (which makes sense) and type 'ostream&' (which
+doesn't).</p>
+<p>The same "cut'n'paste" type also seems to occur in Paras 4,5,7 and
+8. In addition, Para 6 [setfill] has a similar error, but relates only to
+ostreams.</p>
+<p>I'd be happier if there was a better way of saying this, to make it clear
+that the value of the expression is "the same specialization of
+basic_ostream as out"&</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace section 27.6.3 except paragraph 1 with the
+following:</p>
+<blockquote>
+<p>2- The type designated smanip in each of the following function descriptions is implementation-specified and may be different for each
+function.<br>
+<br>
+<tt>smanip resetiosflags(ios_base::fmtflags mask);</tt><br>
+<br>
+-3- Returns: An object s of unspecified type such that if out is an instance of basic_ostream<charT,traits> then the expression out<<s behaves
+as if f(s, mask) were called, or if in is an instance of basic_istream<charT,traits> then the expression in>>s behaves as if
+f(s, mask) were called. The function f can be defined as:*<br>
+<br>
+[Footnote: The expression cin >> resetiosflags(ios_base::skipws) clears ios_base::skipws in the format flags stored in the
+basic_istream<charT,traits> object cin (the same as cin >> noskipws), and the expression cout << resetiosflags(ios_base::showbase) clears
+ios_base::showbase in the format flags stored in the basic_ostream<charT,traits> object cout (the same as cout <<
+noshowbase). --- end footnote]<br>
+<br>
+ <tt>ios_base& f(ios_base& str, ios_base::fmtflags mask)<br>
+ {<br>
+ // reset specified flags<br>
+ str.setf(ios_base::fmtflags(0), mask);<br>
+ return str;<br>
+ }<br>
+</tt><br>
+The expression out<<s has type basic_ostream<charT,traits>& and value out.
+The expression in>>s has type basic_istream<charT,traits>& and value in.<br>
+<br>
+ <tt>smanip setiosflags(ios_base::fmtflags mask);</tt><br>
+<br>
+-4- Returns: An object s of unspecified type such that if out is an instance of basic_ostream<charT,traits> then the expression out<<s behaves
+as if f(s, mask) were called, or if in is an instance of basic_istream<charT,traits> then the expression in>>s behaves as if f(s,
+mask) were called. The function f can be defined as:<br>
+<br>
+ <tt>ios_base& f(ios_base& str, ios_base::fmtflags mask)<br>
+ {<br>
+ // set specified flags<br>
+ str.setf(mask);<br>
+ return str;<br>
+ }<br>
+</tt><br>
+The expression out<<s has type basic_ostream<charT,traits>& and value out.
+The expression in>>s has type basic_istream<charT,traits>& and value in.<br>
+<br>
+<tt>smanip setbase(int base);</tt><br>
+<br>
+-5- Returns: An object s of unspecified type such that if out is an instance of basic_ostream<charT,traits> then the expression out<<s behaves
+as if f(s, base) were called, or if in is an instance of basic_istream<charT,traits> then the expression in>>s behaves as if f(s,
+base) were called. The function f can be defined as:<br>
+<br>
+ <tt>ios_base& f(ios_base& str, int base)<br>
+ {<br>
+ // set basefield<br>
+ str.setf(base == 8 ? ios_base::oct :<br>
+ base == 10 ? ios_base::dec :<br>
+ base == 16 ? ios_base::hex :<br>
+ ios_base::fmtflags(0), ios_base::basefield);<br>
+ return str;<br>
+ }<br>
+</tt><br>
+The expression out<<s has type basic_ostream<charT,traits>& and value out.
+The expression in>>s has type basic_istream<charT,traits>& and value in.<br>
+<br>
+<tt>smanip setfill(char_type c);<br>
+</tt><br>
+-6- Returns: An object s of unspecified type such that if out is (or is derived from) basic_ostream<charT,traits> and c has type charT then the
+expression out<<s behaves as if f(s, c) were called. The function f can be
+defined as:<br>
+<br>
+ <tt>template<class charT, class traits><br>
+ basic_ios<charT,traits>& f(basic_ios<charT,traits>& str, charT c)<br>
+ {<br>
+ // set fill character<br>
+ str.fill(c);<br>
+ return str;<br>
+ }<br>
+</tt><br>
+The expression out<<s has type basic_ostream<charT,traits>& and value out.<br>
+<br>
+<tt>smanip setprecision(int n);</tt><br>
+<br>
+-7- Returns: An object s of unspecified type such that if out is an instance of basic_ostream<charT,traits> then the expression out<<s behaves
+as if f(s, n) were called, or if in is an instance of basic_istream<charT,traits> then the expression in>>s behaves as if f(s, n)
+were called. The function f can be defined as:<br>
+<br>
+ <tt>ios_base& f(ios_base& str, int n)<br>
+ {<br>
+ // set precision<br>
+ str.precision(n);<br>
+ return str;<br>
+ }<br>
+</tt><br>
+The expression out<<s has type basic_ostream<charT,traits>& and value out.
+The expression in>>s has type basic_istream<charT,traits>& and value in<br>
+.<br>
+<tt>smanip setw(int n);<br>
+</tt><br>
+-8- Returns: An object s of unspecified type such that if out is an instance of basic_ostream<charT,traits> then the expression out<<s behaves
+as if f(s, n) were called, or if in is an instance of basic_istream<charT,traits> then the expression in>>s behaves as if f(s, n)
+were called. The function f can be defined as:<br>
+<br>
+ <tt>ios_base& f(ios_base& str, int n)<br>
+ {<br>
+ // set width<br>
+ str.width(n);<br>
+ return str;<br>
+ }<br>
+</tt><br>
+The expression out<<s has type
+basic_ostream<charT,traits>& and value out. The expression
+in>>s has type basic_istream<charT,traits>& and value
+in.
+</p>
+</blockquote>
+
+<p><i>[Kona: Andy Sawyer and Beman Dawes will work to improve the wording of
+the proposed resolution.]</i></p>
+
+<p><i>[Tokyo - The LWG noted that issue <a href="lwg-closed.html#216">216</a> involves
+the same paragraphs.]</i></p>
+
+<p><i>[Post-Tokyo: The issues list maintainer combined the proposed
+resolution of this issue with the proposed resolution for issue <a href="lwg-closed.html#216">216</a> as they both involved the same paragraphs, and were so
+intertwined that dealing with them separately appear fraught with
+error. The full text was supplied by Bill Plauger; it was cross
+checked against changes supplied by Andy Sawyer. It should be further
+checked by the LWG.]</i></p>
+<hr>
+<a name="184"><h3>184. numeric_limits<bool> wording problems</h3></a><p>
+<b>Section:</b> 18.2.1.5 <a href="lib-support.html#lib.numeric.special"> [lib.numeric.special]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Gabriel Dos Reis <b>Date:</b> 21 Jul 1999</p>
+<p>bools are defined by the standard to be of integer types, as per
+3.9.1 paragraph 7. However "integer types"
+seems to have a special meaning for the author of 18.2. The net effect
+is an unclear and confusing specification for
+numeric_limits<bool> as evidenced below.</p>
+
+<p>18.2.1.2/7 says numeric_limits<>::digits is, for built-in integer
+types, the number of non-sign bits in the representation.</p>
+
+<p>4.5/4 states that a bool promotes to int ; whereas 4.12/1 says any non zero
+arithmetical value converts to true.</p>
+
+<p>I don't think it makes sense at all to require
+numeric_limits<bool>::digits and numeric_limits<bool>::digits10 to
+be meaningful.</p>
+
+<p>The standard defines what constitutes a signed (resp. unsigned) integer
+types. It doesn't categorize bool as being signed or unsigned. And the set of
+values of bool type has only two elements.</p>
+
+<p>I don't think it makes sense to require numeric_limits<bool>::is_signed
+to be meaningful.</p>
+
+<p>18.2.1.2/18 for numeric_limits<integer_type>::radix says:</p>
+<blockquote>
+ <p>For integer types, specifies the base of the representation.186)</p>
+</blockquote>
+
+<p>This disposition is at best misleading and confusing for the standard
+requires a "pure binary numeration system" for integer types as per
+3.9.1/7</p>
+
+<p>The footnote 186) says: "Distinguishes types with base other than 2 (e.g
+BCD)." This also erroneous as the standard never defines any integer
+types with base representation other than 2.</p>
+
+<p>Furthermore, numeric_limits<bool>::is_modulo and
+numeric_limits<bool>::is_signed have similar problems.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Append to the end of 18.2.1.5 :</p>
+<blockquote>
+ <p>The specialization for bool shall be provided as follows:</p>
+ <pre> namespace std {
+ template<> class numeric_limits<bool> {
+ public:
+ static const bool is_specialized = true;
+ static bool min() throw() { return false; }
+ static bool max() throw() { return true; }
+
+ static const int digits = 1;
+ static const int digits10 = 0;
+ static const bool is_signed = false;
+ static const bool is_integer = true;
+ static const bool is_exact = true;
+ static const int radix = 2;
+ static bool epsilon() throw() { return 0; }
+ static bool round_error() throw() { return 0; }
+
+ static const int min_exponent = 0;
+ static const int min_exponent10 = 0;
+ static const int max_exponent = 0;
+ static const int max_exponent10 = 0;
+
+ static const bool has_infinity = false;
+ static const bool has_quiet_NaN = false;
+ static const bool has_signaling_NaN = false;
+ static const float_denorm_style has_denorm = denorm_absent;
+ static const bool has_denorm_loss = false;
+ static bool infinity() throw() { return 0; }
+ static bool quiet_NaN() throw() { return 0; }
+ static bool signaling_NaN() throw() { return 0; }
+ static bool denorm_min() throw() { return 0; }
+
+ static const bool is_iec559 = false;
+ static const bool is_bounded = true;
+ static const bool is_modulo = false;
+
+ static const bool traps = false;
+ static const bool tinyness_before = false;
+ static const float_round_style round_style = round_toward_zero;
+ };
+ }</pre>
+</blockquote>
+
+<p><i>[Tokyo: The LWG desires wording that specifies exact values
+rather than more general wording in the original proposed
+resolution.]</i></p>
+
+<p><i>[Post-Tokyo: At the request of the LWG in Tokyo, Nico
+Josuttis provided the above wording.]</i></p>
+<hr>
+<a name="185"><h3>185. Questionable use of term "inline"</h3></a><p>
+<b>Section:</b> 20.3 <a href="lib-utilities.html#lib.function.objects"> [lib.function.objects]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> UK Panel <b>Date:</b> 26 Jul 1999</p>
+<p>Paragraph 4 of 20.3 says:</p>
+<blockquote>
+ <p> [Example: To negate every element of a: transform(a.begin(), a.end(),
+ a.begin(), negate<double>()); The corresponding functions will inline
+ the addition and the negation. end example]</p>
+</blockquote>
+<p>(Note: The "addition" referred to in the above is in para 3) we can
+find no other wording, except this (non-normative) example which suggests that
+any "inlining" will take place in this case.</p>
+<p>Indeed both:</p>
+<blockquote>
+ <p>17.4.4.3 Global Functions [lib.global.functions] 1 It is
+ unspecified whether any global functions in the C++ Standard Library
+ are defined as inline (7.1.2).</p>
+</blockquote>
+<p>and</p>
+<blockquote>
+ <p>17.4.4.4 Member Functions [lib.member.functions] 1 It is
+ unspecified whether any member functions in the C++ Standard Library
+ are defined as inline (7.1.2).</p>
+</blockquote>
+<p>take care to state that this may indeed NOT be the case.</p>
+<p>Thus the example "mandates" behavior that is explicitly
+not required elsewhere.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 20.3 paragraph 1, remove the sentence:</p>
+<blockquote>
+<p>They are important for the effective use of the library.</p>
+</blockquote>
+<p>Remove 20.3 paragraph 2, which reads:</p>
+<blockquote>
+ <p> Using function objects together with function templates
+ increases the expressive power of the library as well as making the
+ resulting code much more efficient.</p>
+</blockquote>
+<p>In 20.3 paragraph 4, remove the sentence:</p>
+<blockquote>
+ <p>The corresponding functions will inline the addition and the
+ negation.</p>
+</blockquote>
+
+<p><i>[Kona: The LWG agreed there was a defect.]</i></p>
+<p><i>[Tokyo: The LWG crafted the proposed resolution.]</i></p>
+<hr>
+<a name="186"><h3>186. bitset::set() second parameter should be bool</h3></a><p>
+<b>Section:</b> 23.3.5.2 <a href="lib-containers.html#lib.bitset.members"> [lib.bitset.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Darin Adler <b>Date:</b> 13 Aug 1999</p>
+<p>In section 23.3.5.2 , paragraph 13 defines the
+bitset::set operation to take a second parameter of type int. The
+function tests whether this value is non-zero to determine whether to
+set the bit to true or false. The type of this second parameter should
+be bool. For one thing, the intent is to specify a Boolean value. For
+another, the result type from test() is bool. In addition, it's
+possible to slice an integer that's larger than an int. This can't
+happen with bool, since conversion to bool has the semantic of
+translating 0 to false and any non-zero value to true.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 23.3.5 Para 1 Replace:</p>
+<blockquote>
+<pre>bitset<N>& set(size_t pos, int val = true ); </pre>
+</blockquote>
+<p>With:</p>
+<blockquote>
+ <pre>bitset<N>& set(size_t pos, bool val = true );</pre>
+</blockquote>
+<p>In 23.3.5.2 Para 12(.5) Replace:</p>
+<blockquote>
+ <pre>bitset<N>& set(size_t pos, int val = 1 );</pre>
+</blockquote>
+<p>With:</p>
+<blockquote>
+ <pre>bitset<N>& set(size_t pos, bool val = true );</pre>
+</blockquote>
+
+<p><i>[Kona: The LWG agrees with the description. Andy Sawyer will work
+on better P/R wording.]</i></p>
+<p><i>[Post-Tokyo: Andy provided the above wording.]</i></p>
+<p><b>Rationale:</b></p>
+<p>
+<tt>bool</tt> is a better choice. It is believed that binary
+compatibility is not an issue, because this member function is
+usually implemented as <tt>inline</tt>, and because it is already
+the case that users cannot rely on the type of a pointer to a
+nonvirtual member of a standard library class.</p>
+<hr>
+<a name="189"><h3>189. setprecision() not specified correctly</h3></a><p>
+<b>Section:</b> 27.4.2.2 <a href="lib-iostreams.html#lib.fmtflags.state"> [lib.fmtflags.state]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Andrew Koenig <b>Date:</b> 25 Aug 1999</p>
+<p>27.4.2.2 paragraph 9 claims that setprecision() sets the precision,
+and includes a parenthetical note saying that it is the number of
+digits after the decimal point.<br>
+<br>
+This claim is not strictly correct. For example, in the default
+floating-point output format, setprecision sets the number of
+significant digits printed, not the number of digits after the decimal
+point.<br>
+<br>
+I would like the committee to look at the definition carefully and
+correct the statement in 27.4.2.2</p>
+<p><b>Proposed resolution:</b></p>
+<p>Remove from 27.4.2.2 , paragraph 9, the text
+"(number of digits after the decimal point)".</p>
+<hr>
+<a name="193"><h3>193. Heap operations description incorrect</h3></a><p>
+<b>Section:</b> 25.3.6 <a href="lib-algorithms.html#lib.alg.heap.operations"> [lib.alg.heap.operations]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Markus Mauhart <b>Date:</b> 24 Sep 1999</p>
+<p>25.3.6 [lib.alg.heap.operations] states two key properties of a heap [a,b), the first of them
+is<br>
+<br>
+ `"(1) *a is the largest element"<br>
+<br>
+I think this is incorrect and should be changed to the wording in the proposed
+resolution.</p>
+<p>Actually there are two independent changes:</p>
+<blockquote>
+ <p>A-"part of largest equivalence class" instead of "largest", cause 25.3
+ [lib.alg.sorting] asserts "strict weak ordering" for all its sub clauses.</p>
+ <p>B-Take 'an oldest' from that equivalence class, otherwise the heap functions could not be used for a
+ priority queue as explained in 23.2.3.2.2 [lib.priqueue.members] (where I assume that a "priority queue" respects priority AND time).</p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>Change 25.3.6 property (1) from:</p>
+<blockquote>
+ <p>(1) *a is the largest element</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+ <p>(1) There is no element greater than <tt>*a</tt>
+</p>
+</blockquote>
+<hr>
+<a name="195"><h3>195. Should <tt>basic_istream::sentry</tt>'s constructor ever set eofbit?</h3></a><p>
+<b>Section:</b> 27.6.1.1.2 <a href="lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 13 Oct 1999</p>
+<p>Suppose that <tt>is.flags() & ios_base::skipws</tt> is nonzero.
+What should <tt>basic_istream<>::sentry</tt>'s constructor do if it
+reaches eof while skipping whitespace? 27.6.1.1.2/5 suggests it
+should set failbit. Should it set eofbit as well? The standard
+doesn't seem to answer that question.</p>
+
+<p>On the one hand, nothing in 27.6.1.1.2 says that
+<tt>basic_istream<>::sentry</tt> should ever set eofbit. On the
+other hand, 27.6.1.1 paragraph 4 says that if
+extraction from a <tt>streambuf</tt> "returns
+<tt>traits::eof()</tt>, then the input function, except as explicitly
+noted otherwise, completes its actions and does
+<tt>setstate(eofbit)"</tt>. So the question comes down to
+whether <tt>basic_istream<>::sentry</tt>'s constructor is an
+input function.</p>
+
+<p>Comments from Jerry Schwarz:</p>
+<blockquote>
+<p>It was always my intention that eofbit should be set any time that a
+virtual returned something to indicate eof, no matter what reason
+iostream code had for calling the virtual.</p>
+<p>
+The motivation for this is that I did not want to require streambufs
+to behave consistently if their virtuals are called after they have
+signaled eof.</p>
+<p>
+The classic case is a streambuf reading from a UNIX file. EOF isn't
+really a state for UNIX file descriptors. The convention is that a
+read on UNIX returns 0 bytes to indicate "EOF", but the file
+descriptor isn't shut down in any way and future reads do not
+necessarily also return 0 bytes. In particular, you can read from
+tty's on UNIX even after they have signaled "EOF". (It
+isn't always understood that a ^D on UNIX is not an EOF indicator, but
+an EOL indicator. By typing a "line" consisting solely of
+^D you cause a read to return 0 bytes, and by convention this is
+interpreted as end of file.)</p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>Add a sentence to the end of 27.6.1.1.2 paragraph 2:</p>
+<blockquote>
+<p>If <tt>is.rdbuf()->sbumpc()</tt> or <tt>is.rdbuf()->sgetc()</tt>
+returns <tt>traits::eof()</tt>, the function calls
+<tt>setstate(failbit | eofbit)</tt> (which may throw
+<tt>ios_base::failure</tt>).
+</p>
+</blockquote>
+<hr>
+<a name="199"><h3>199. What does <tt>allocate(0)</tt> return?</h3></a><p>
+<b>Section:</b> 20.1.5 <a href="lib-utilities.html#lib.allocator.requirements"> [lib.allocator.requirements]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 19 Nov 1999</p>
+<p>
+Suppose that <tt>A</tt> is a class that conforms to the
+Allocator requirements of Table 32, and <tt>a</tt> is an
+object of class <tt>A</tt> What should be the return
+value of <tt>a.allocate(0)</tt>? Three reasonable
+possibilities: forbid the argument <tt>0</tt>, return
+a null pointer, or require that the return value be a
+unique non-null pointer.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Add a note to the <tt>allocate</tt> row of Table 32:
+"[<i>Note:</i> If <tt>n == 0</tt>, the return value is unspecified. <i>--end note</i>]"</p>
+<p><b>Rationale:</b></p>
+<p>A key to understanding this issue is that the ultimate use of
+allocate() is to construct an iterator, and that iterator for zero
+length sequences must be the container's past-the-end
+representation. Since this already implies special case code, it
+would be over-specification to mandate the return value.
+</p>
+<hr>
+<a name="208"><h3>208. Unnecessary restriction on past-the-end iterators</h3></a><p>
+<b>Section:</b> 24.1 <a href="lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Stephen Cleary <b>Date:</b> 02 Feb 2000</p>
+<p>In 24.1 paragraph 5, it is stated ". . . Dereferenceable and
+past-the-end values are always non-singular."</p>
+<p>This places an unnecessary restriction on past-the-end iterators for
+containers with forward iterators (for example, a singly-linked list). If the
+past-the-end value on such a container was a well-known singular value, it would
+still satisfy all forward iterator requirements.</p>
+<p>Removing this restriction would allow, for example, a singly-linked list
+without a "footer" node.</p>
+<p>This would have an impact on existing code that expects past-the-end
+iterators obtained from different (generic) containers being not equal.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change 24.1 paragraph 5, the last sentence, from:</p>
+<blockquote>
+<p>Dereferenceable and past-the-end values are always non-singular.</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+<p>Dereferenceable values are always non-singular. </p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>For some kinds of containers, including singly linked lists and
+zero-length vectors, null pointers are perfectly reasonable past-the-end
+iterators. Null pointers are singular.
+</p>
+<hr>
+<a name="209"><h3>209. basic_string declarations inconsistent</h3></a><p>
+<b>Section:</b> 21.3 <a href="lib-strings.html#lib.basic.string"> [lib.basic.string]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Igor Stauder <b>Date:</b> 11 Feb 2000</p>
+<p>In Section 21.3 the basic_string member function
+declarations use a consistent style except for the following functions:</p>
+<blockquote>
+ <pre>void push_back(const charT);
+basic_string& assign(const basic_string&);
+void swap(basic_string<charT,traits,Allocator>&);</pre>
+</blockquote>
+<p>- push_back, assign, swap: missing argument name <br>
+- push_back: use of const with charT (i.e. POD type passed by value
+not by reference - should be charT or const charT& )<br>
+- swap: redundant use of template parameters in argument
+basic_string<charT,traits,Allocator>&</p>
+<p><b>Proposed resolution:</b></p>
+<p>In Section 21.3 change the basic_string member
+function declarations push_back, assign, and swap to:</p>
+<blockquote>
+ <pre>void push_back(charT c);
+
+basic_string& assign(const basic_string& str);
+void swap(basic_string& str);</pre>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Although the standard is in general not consistent in declaration
+style, the basic_string declarations are consistent other than the
+above. The LWG felt that this was sufficient reason to merit the
+change.
+</p>
+<hr>
+<a name="210"><h3>210. distance first and last confused</h3></a><p>
+<b>Section:</b> 25 <a href="lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Lisa Lippincott <b>Date:</b> 15 Feb 2000</p>
+<p>In paragraph 9 of section 25 , it is written:</p>
+<blockquote>
+ <p> In the description of the algorithms operators + and - are used
+ for some of the iterator categories for which they do not have to
+ be defined. In these cases the semantics of [...] a-b is the same
+ as of<br>
+ <br>
+ <tt>return distance(a, b);</tt>
+</p>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>On the last line of paragraph 9 of section 25 change
+<tt>"a-b"</tt> to <tt>"b-a".</tt>
+</p>
+<p><b>Rationale:</b></p>
+<p>There are two ways to fix the defect; change the description to b-a
+or change the return to distance(b,a). The LWG preferred the
+former for consistency.</p>
+<hr>
+<a name="211"><h3>211. operator>>(istream&, string&) doesn't set failbit</h3></a><p>
+<b>Section:</b> 21.3.7.9 <a href="lib-strings.html#lib.string.io"> [lib.string.io]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Scott Snyder <b>Date:</b> 4 Feb 2000</p>
+<p>The description of the stream extraction operator for std::string (section
+21.3.7.9 [lib.string.io]) does not contain a requirement that failbit be set in
+the case that the operator fails to extract any characters from the input
+stream.</p>
+<p>This implies that the typical construction</p>
+<blockquote>
+ <pre>std::istream is;
+std::string str;
+...
+while (is >> str) ... ;</pre>
+</blockquote>
+<p>(which tests failbit) is not required to terminate at EOF.</p>
+<p>Furthermore, this is inconsistent with other extraction operators,
+which do include this requirement. (See sections 27.6.1.2 and 27.6.1.3 ), where this
+requirement is present, either explicitly or implicitly, for the
+extraction operators. It is also present explicitly in the description
+of getline (istream&, string&, charT) in section 21.3.7.9 paragraph 8.)</p>
+<p><b>Proposed resolution:</b></p>
+<p>Insert new paragraph after paragraph 2 in section 21.3.7.9 :</p>
+<blockquote>
+
+<p>If the function extracts no characters, it calls
+is.setstate(ios::failbit) which may throw ios_base::failure
+(27.4.4.3).</p>
+</blockquote>
+<hr>
+<a name="212"><h3>212. Empty range behavior unclear for several algorithms</h3></a><p>
+<b>Section:</b> 25.3.7 <a href="lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Nico Josuttis <b>Date:</b> 26 Feb 2000</p>
+<p>The standard doesn't specify what min_element() and max_element() shall
+return if the range is empty (first equals last). The usual implementations
+return last. This problem seems also apply to partition(), stable_partition(),
+next_permutation(), and prev_permutation().</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 25.3.7 - Minimum and maximum, paragraphs 7 and
+9, append: Returns last if first==last.</p>
+<p><b>Rationale:</b></p>
+<p>The LWG looked in some detail at all of the above mentioned
+algorithms, but believes that except for min_element() and
+max_element() it is already clear that last is returned if first ==
+last.</p>
+<hr>
+<a name="214"><h3>214. set::find() missing const overload</h3></a><p>
+<b>Section:</b> 23.3.3 <a href="lib-containers.html#lib.set"> [lib.set]</a>, 23.3.4 <a href="lib-containers.html#lib.multiset"> [lib.multiset]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 28 Feb 2000</p>
+<p>The specification for the associative container requirements in
+Table 69 state that the find member function should "return
+iterator; const_iterator for constant a". The map and multimap
+container descriptions have two overloaded versions of find, but set
+and multiset do not, all they have is:</p>
+<blockquote>
+ <pre>iterator find(const key_type & x) const;</pre>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>Change the prototypes for find(), lower_bound(), upper_bound(), and
+equal_range() in section 23.3.3 and section 23.3.4 to each have two overloads:</p>
+<blockquote>
+ <pre>iterator find(const key_type & x);
+const_iterator find(const key_type & x) const;</pre>
+ <pre>iterator lower_bound(const key_type & x);
+const_iterator lower_bound(const key_type & x) const;</pre>
+ <pre>iterator upper_bound(const key_type & x);
+const_iterator upper_bound(const key_type & x) const;</pre>
+ <pre>pair<iterator, iterator> equal_range(const key_type & x);
+pair<const_iterator, const_iterator> equal_range(const key_type & x) const;</pre>
+</blockquote>
+
+<p><i>[Tokyo: At the request of the LWG, Judy Ward provided wording
+extending the proposed resolution to lower_bound, upper_bound, and
+equal_range.]</i></p>
+<hr>
+<a name="217"><h3>217. Facets example (Classifying Japanese characters) contains errors</h3></a><p>
+<b>Section:</b> 22.2.8 <a href="lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 29 Feb 2000</p>
+<p>The example in 22.2.8, paragraph 11 contains the following errors:</p>
+<p>1) The member function `My::JCtype::is_kanji()' is non-const; the function
+must be const in order for it to be callable on a const object (a reference to
+which which is what std::use_facet<>() returns).</p>
+<p>2) In file filt.C, the definition of `JCtype::id' must be qualified with the
+name of the namespace `My'.</p>
+<p>3) In the definition of `loc' and subsequently in the call to use_facet<>()
+in main(), the name of the facet is misspelled: it should read `My::JCtype'
+rather than `My::JCType'.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace the "Classifying Japanese characters" example in 22.2.8,
+paragraph 11 with the following:</p>
+<pre>#include <locale></pre>
+<pre>namespace My {
+ using namespace std;
+ class JCtype : public locale::facet {
+ public:
+ static locale::id id; // required for use as a new locale facet
+ bool is_kanji (wchar_t c) const;
+ JCtype() {}
+ protected:
+ ~JCtype() {}
+ };
+}</pre>
+<pre>// file: filt.C
+#include <iostream>
+#include <locale>
+#include "jctype" // above
+std::locale::id My::JCtype::id; // the static JCtype member
+declared above.</pre>
+<pre>int main()
+{
+ using namespace std;
+ typedef ctype<wchar_t> wctype;
+ locale loc(locale(""), // the user's preferred locale...
+ new My::JCtype); // and a new feature ...
+ wchar_t c = use_facet<wctype>(loc).widen('!');
+ if (!use_facet<My::JCtype>(loc).is_kanji(c))
+ cout << "no it isn't!" << endl;
+ return 0;
+}</pre>
+<hr>
+<a name="220"><h3>220. ~ios_base() usage valid?</h3></a><p>
+<b>Section:</b> 27.4.2.7 <a href="lib-iostreams.html#lib.ios.base.cons"> [lib.ios.base.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Jonathan Schilling, Howard Hinnant <b>Date:</b> 13 Mar 2000</p>
+<p>The pre-conditions for the ios_base destructor are described in 27.4.2.7
+paragraph 2:</p>
+<blockquote>
+ <p>Effects: Destroys an object of class ios_base. Calls each registered
+ callback pair (fn,index) (27.4.2.6) as (*fn)(erase_event,*this,index) at such
+ time that any ios_base member function called from within fn has well defined
+ results.</p>
+</blockquote>
+<p>But what is not clear is: If no callback functions were ever registered, does
+it matter whether the ios_base members were ever initialized?</p>
+<p>For instance, does this program have defined behavior:</p>
+<blockquote>
+ <pre>#include <ios></pre>
+ <pre>class D : public std::ios_base { };</pre>
+ <pre>int main() { D d; }</pre>
+</blockquote>
+<p>It seems that registration of a callback function would surely affect the
+state of an ios_base. That is, when you register a callback function with an
+ios_base, the ios_base must record that fact somehow.</p>
+<p>But if after construction the ios_base is in an indeterminate state, and that
+state is not made determinate before the destructor is called, then how would
+the destructor know if any callbacks had indeed been registered? And if the
+number of callbacks that had been registered is indeterminate, then is not the
+behavior of the destructor undefined?</p>
+<p>By comparison, the basic_ios class description in 27.4.4.1 paragraph 2 makes
+it explicit that destruction before initialization results in undefined
+behavior.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Modify 27.4.2.7 paragraph 1 from</p>
+<blockquote>
+ <p>Effects: Each ios_base member has an indeterminate value after
+ construction.</p>
+</blockquote>
+<p>to</p>
+<blockquote>
+ <p>Effects: Each ios_base member has an indeterminate value after
+ construction. These members must be initialized by calling basic_ios::init. If an ios_base object is destroyed before these initializations
+ have taken place, the behavior is undefined.</p>
+</blockquote>
+<hr>
+<a name="221"><h3>221. num_get<>::do_get stage 2 processing broken</h3></a><p>
+<b>Section:</b> 22.2.2.1.2 <a href="lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Matt Austern <b>Date:</b> 14 Mar 2000</p>
+<p>Stage 2 processing of numeric conversion is broken.</p>
+
+<p>Table 55 in 22.2.2.1.2 says that when basefield is 0 the integral
+conversion specifier is %i. A %i specifier determines a number's base
+by its prefix (0 for octal, 0x for hex), so the intention is clearly
+that a 0x prefix is allowed. Paragraph 8 in the same section,
+however, describes very precisely how characters are processed. (It
+must be done "as if" by a specified code fragment.) That
+description does not allow a 0x prefix to be recognized.</p>
+
+<p>Very roughly, stage 2 processing reads a char_type ct. It converts
+ct to a char, not by using narrow but by looking it up in a
+translation table that was created by widening the string literal
+"0123456789abcdefABCDEF+-". The character "x" is
+not found in that table, so it can't be recognized by stage 2
+processing.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 22.2.2.1.2 paragraph 8, replace the line:</p>
+<blockquote>
+ <pre>static const char src[] = "0123456789abcdefABCDEF+-";</pre>
+</blockquote>
+<p>with the line:</p>
+<blockquote>
+ <pre>static const char src[] = "0123456789abcdefxABCDEFX+-";</pre>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>If we're using the technique of widening a string literal, the
+string literal must contain every character we wish to recognize.
+This technique has the consequence that alternate representations
+of digits will not be recognized. This design decision was made
+deliberately, with full knowledge of that limitation.</p>
+<hr>
+<a name="222"><h3>222. Are throw clauses necessary if a throw is already implied by the effects clause?</h3></a><p>
+<b>Section:</b> 17.3.1.3 <a href="lib-intro.html#lib.structure.specifications"> [lib.structure.specifications]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Judy Ward <b>Date:</b> 17 Mar 2000</p>
+<p>Section 21.3.6.8 describes the basic_string::compare function this way:</p>
+<blockquote>
+ <pre>21.3.6.8 - basic_string::compare [lib.string::compare]
+
+int compare(size_type pos1, size_type n1,
+ const basic_string<charT,traits,Allocator>& str ,
+ size_type pos2 , size_type n2 ) const;
+
+-4- Returns:
+
+ basic_string<charT,traits,Allocator>(*this,pos1,n1).compare(
+ basic_string<charT,traits,Allocator>(str,pos2,n2)) .</pre>
+</blockquote>
+<p>and the constructor that's implicitly called by the above is
+defined to throw an out-of-range exception if pos > str.size(). See
+section 21.3.1 paragraph 4.</p>
+
+<p>On the other hand, the compare function descriptions themselves don't have
+"Throws: " clauses and according to 17.3.1.3, paragraph 3, elements
+that do not apply to a function are omitted.</p>
+<p>So it seems there is an inconsistency in the standard -- are the
+"Effects" clauses correct, or are the "Throws" clauses
+missing?</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 17.3.1.3 paragraph 3, the footnote 148 attached to
+the sentence "Descriptions of function semantics contain the
+following elements (as appropriate):", insert the word
+"further" so that the foot note reads:</p>
+<blockquote>
+ <p>To save space, items that do not apply to a function are
+ omitted. For example, if a function does not specify any further
+ preconditions, there will be no "Requires" paragraph.</p>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The standard is somewhat inconsistent, but a failure to note a
+throw condition in a throws clause does not grant permission not to
+throw. The inconsistent wording is in a footnote, and thus
+non-normative. The proposed resolution from the LWG clarifies the
+footnote.</p>
+<hr>
+<a name="223"><h3>223. reverse algorithm should use iter_swap rather than swap</h3></a><p>
+<b>Section:</b> 25.2.9 <a href="lib-algorithms.html#lib.alg.reverse"> [lib.alg.reverse]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 21 Mar 2000</p>
+<p>Shouldn't the effects say "applies iter_swap to all pairs..."?</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 25.2.9 , replace:</p>
+ <blockquote>
+ Effects: For each non-negative integer i <= (last - first)/2,
+ applies swap to all pairs of iterators first + i, (last - i) - 1.
+ </blockquote>
+<p>with:</p>
+ <blockquote>
+ Effects: For each non-negative integer i <= (last - first)/2,
+ applies iter_swap to all pairs of iterators first + i, (last - i) - 1.
+ </blockquote>
+<hr>
+<a name="224"><h3>224. clear() complexity for associative containers refers to undefined N</h3></a><p>
+<b>Section:</b> 23.1.2 <a href="lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Ed Brey <b>Date:</b> 23 Mar 2000</p>
+<p>In the associative container requirements table in 23.1.2 paragraph 7,
+a.clear() has complexity "log(size()) + N". However, the meaning of N
+is not defined.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In the associative container requirements table in 23.1.2 paragraph
+7, the complexity of a.clear(), change "log(size()) + N" to
+"linear in <tt>size()</tt>".</p>
+<p><b>Rationale:</b></p>
+<p>It's the "log(size())", not the "N", that is in
+error: there's no difference between <i>O(N)</i> and <i>O(N +
+log(N))</i>. The text in the standard is probably an incorrect
+cut-and-paste from the range version of <tt>erase</tt>.</p>
+<hr>
+<a name="227"><h3>227. std::swap() should require CopyConstructible or DefaultConstructible arguments</h3></a><p>
+<b>Section:</b> 25.2.2 <a href="lib-algorithms.html#lib.alg.swap"> [lib.alg.swap]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dave Abrahams <b>Date:</b> 09 Apr 2000</p>
+<p>25.2.2 reads:</p>
+<blockquote>
+ <p>
+<tt> template<class T> void swap(T& a, T& b);</tt><br>
+ <br>
+ Requires: Type T is Assignable (_lib.container.requirements_).<br>
+ Effects: Exchanges values stored in two locations.</p>
+</blockquote>
+<p>The only reasonable** generic implementation of swap requires construction of a
+ new temporary copy of one of its arguments:</p>
+<blockquote>
+<pre>template<class T> void swap(T& a, T& b);
+ {
+ T tmp(a);
+ a = b;
+ b = tmp;
+ }</pre>
+</blockquote>
+<p>But a type which is only Assignable cannot be swapped by this implementation.</p>
+<p>**Yes, there's also an unreasonable implementation which would require T to be
+ DefaultConstructible instead of CopyConstructible. I don't think this is worthy
+ of consideration:</p>
+<blockquote>
+<pre>template<class T> void swap(T& a, T& b);
+{
+ T tmp;
+ tmp = a;
+ a = b;
+ b = tmp;
+}</pre>
+</blockquote>
+<p><b>Proposed resolution:</b></p>
+<p>Change 25.2.2 paragraph 1 from:</p>
+<blockquote>
+<p> Requires: Type T is Assignable (23.1).</p>
+</blockquote>
+<p>to:</p>
+<blockquote>
+<p> Requires: Type T is CopyConstructible (20.1.3) and Assignable (23.1)</p>
+</blockquote>
+<hr>
+<a name="234"><h3>234. Typos in allocator definition</h3></a><p>
+<b>Section:</b> 20.4.1.1 <a href="lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 24 Apr 2000</p>
+<p>In paragraphs 12 and 13 the effects of <tt>construct()</tt> and
+<tt>destruct()</tt> are described as returns but the functions actually
+return <tt>void</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Substitute "Returns" by "Effect".</p>
+<hr>
+<a name="237"><h3>237. Undefined expression in complexity specification</h3></a><p>
+<b>Section:</b> 23.2.2.1 <a href="lib-containers.html#lib.list.cons"> [lib.list.cons]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Dietmar Kühl <b>Date:</b> 24 Apr 2000</p>
+<p>The complexity specification in paragraph 6 says that the complexity
+is linear in <tt>first - last</tt>. Even if <tt>operator-()</tt> is
+defined on iterators this term is in general undefined because it
+would have to be <tt>last - first</tt>.</p>
+<p><b>Proposed resolution:</b></p>
+ <p>Change paragraph 6 from</p>
+ <blockquote>Linear in <i>first - last</i>.</blockquote>
+ <p>to become</p>
+ <blockquote>Linear in <i>distance(first, last)</i>.</blockquote>
+<hr>
+<a name="243"><h3>243. <tt>get</tt> and <tt>getline</tt> when sentry reports failure</h3></a><p>
+<b>Section:</b> 27.6.1.3 <a href="lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> May 15 2000</p>
+<p>basic_istream<>::get(), and basic_istream<>::getline(),
+are unclear with respect to the behavior and side-effects of the named
+functions in case of an error.</p>
+
+<p>27.6.1.3, p1 states that "... If the sentry object returns
+true, when converted to a value of type bool, the function endeavors
+to obtain the requested input..." It is not clear from this (or
+the rest of the paragraph) what precisely the behavior should be when
+the sentry ctor exits by throwing an exception or when the sentry
+object returns false. In particular, what is the number of characters
+extracted that gcount() returns supposed to be?</p>
+
+<p>27.6.1.3 p8 and p19 say about the effects of get() and getline():
+"... In any case, it then stores a null character (using
+charT()) into the next successive location of the array." Is not
+clear whether this sentence applies if either of the conditions above
+holds (i.e., when sentry fails).</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add to 27.6.1.3, p1 after the sentence</p>
+
+<blockquote>
+"... If the sentry object returns true, when converted to a value of
+type bool, the function endeavors to obtain the requested input."
+</blockquote>
+
+<p>the following</p>
+
+
+<blockquote>
+"Otherwise, if the sentry constructor exits by throwing an exception or
+if the sentry object returns false, when converted to a value of type
+bool, the function returns without attempting to obtain any input. In
+either case the number of extracted characters is set to 0; unformatted
+input functions taking a character array of non-zero size as an argument
+shall also store a null character (using charT()) in the first location
+of the array."
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Although the general philosophy of the input functions is that the
+argument should not be modified upon failure, <tt>getline</tt>
+historically added a terminating null unconditionally. Most
+implementations still do that. Earlier versions of the draft standard
+had language that made this an unambiguous requirement; those words
+were moved to a place where their context made them less clear. See
+Jerry Schwarz's message c++std-lib-7618.</p>
+<hr>
+<a name="248"><h3>248. time_get fails to set eofbit</h3></a><p>
+<b>Section:</b> 22.2.5 <a href="lib-locales.html#lib.category.time"> [lib.category.time]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 22 June 2000</p>
+<p>There is no requirement that any of time_get member functions set
+ios::eofbit when they reach the end iterator while parsing their input.
+Since members of both the num_get and money_get facets are required to
+do so (22.2.2.1.2, and 22.2.6.1.2, respectively), time_get members
+should follow the same requirement for consistency.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add paragraph 2 to section 22.2.5.1 with the following text:</p>
+
+<blockquote>
+If the end iterator is reached during parsing by any of the get()
+member functions, the member sets ios_base::eofbit in err.
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>Two alternative resolutions were proposed. The LWG chose this one
+because it was more consistent with the way eof is described for other
+input facets.</p>
+<hr>
+<a name="251"><h3>251. basic_stringbuf missing allocator_type</h3></a><p>
+<b>Section:</b> 27.7.1 <a href="lib-iostreams.html#lib.stringbuf"> [lib.stringbuf]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 28 Jul 2000</p>
+<p>The synopsis for the template class <tt>basic_stringbuf</tt>
+doesn't list a typedef for the template parameter
+<tt>Allocator</tt>. This makes it impossible to determine the type of
+the allocator at compile time. It's also inconsistent with all other
+template classes in the library that do provide a typedef for the
+<tt>Allocator</tt> parameter.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add to the synopses of the class templates basic_stringbuf (27.7.1),
+basic_istringstream (27.7.2), basic_ostringstream (27.7.3), and
+basic_stringstream (27.7.4) the typedef:</p>
+<pre>
+ typedef Allocator allocator_type;
+</pre>
+<hr>
+<a name="252"><h3>252. missing casts/C-style casts used in iostreams</h3></a><p>
+<b>Section:</b> 27.7 <a href="lib-iostreams.html#lib.string.streams"> [lib.string.streams]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 28 Jul 2000</p>
+<p>27.7.2.2, p1 uses a C-style cast rather than the more appropriate
+const_cast<> in the Returns clause for basic_istringstream<>::rdbuf().
+The same C-style cast is being used in 27.7.3.2, p1, D.7.2.2, p1, and
+D.7.3.2, p1, and perhaps elsewhere. 27.7.6, p1 and D.7.2.2, p1 are missing
+the cast altogether.</p>
+
+<p>C-style casts have not been deprecated, so the first part of this
+issue is stylistic rather than a matter of correctness.</p>
+<p><b>Proposed resolution:</b></p>
+<p>In 27.7.2.2, p1 replace </p>
+<pre> -1- Returns: (basic_stringbuf<charT,traits,Allocator>*)&sb.</pre>
+
+<p>with</p>
+<pre> -1- Returns: const_cast<basic_stringbuf<charT,traits,Allocator>*>(&sb).</pre>
+
+
+<p>In 27.7.3.2, p1 replace</p>
+<pre> -1- Returns: (basic_stringbuf<charT,traits,Allocator>*)&sb.</pre>
+
+<p>with</p>
+<pre> -1- Returns: const_cast<basic_stringbuf<charT,traits,Allocator>*>(&sb).</pre>
+
+<p>In 27.7.6, p1, replace</p>
+<pre> -1- Returns: &sb</pre>
+
+<p>with</p>
+<pre> -1- Returns: const_cast<basic_stringbuf<charT,traits,Allocator>*>(&sb).</pre>
+
+<p>In D.7.2.2, p1 replace</p>
+<pre> -2- Returns: &sb. </pre>
+
+<p>with</p>
+<pre> -2- Returns: const_cast<strstreambuf*>(&sb).</pre>
+<hr>
+<a name="256"><h3>256. typo in 27.4.4.2, p17: copy_event does not exist</h3></a><p>
+<b>Section:</b> 27.4.4.2 <a href="lib-iostreams.html#lib.basic.ios.members"> [lib.basic.ios.members]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 21 Aug 2000</p>
+<p>
+27.4.4.2, p17 says
+</p>
+
+<blockquote>
+-17- Before copying any parts of rhs, calls each registered callback
+pair (fn,index) as (*fn)(erase_event,*this,index). After all parts but
+exceptions() have been replaced, calls each callback pair that was
+copied from rhs as (*fn)(copy_event,*this,index).
+</blockquote>
+
+<p>
+The name copy_event isn't defined anywhere. The intended name was
+copyfmt_event.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Replace copy_event with copyfmt_event in the named paragraph.</p>
+<hr>
+<a name="260"><h3>260. Inconsistent return type of <tt>istream_iterator::operator++(int)</tt>
+</h3></a><p>
+<b>Section:</b> 24.5.1.2 <a href="lib-iterators.html#lib.istream.iterator.ops"> [lib.istream.iterator.ops]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 27 Aug 2000</p>
+<p>The synopsis of istream_iterator::operator++(int) in 24.5.1 shows
+it as returning the iterator by value. 24.5.1.2, p5 shows the same
+operator as returning the iterator by reference. That's incorrect
+given the Effects clause below (since a temporary is returned). The
+`&' is probably just a typo.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the declaration in 24.5.1.2, p5 from</p>
+ <pre>
+ istream_iterator<T,charT,traits,Distance>& operator++(int);
+ </pre>
+<p>to</p>
+ <pre>
+ istream_iterator<T,charT,traits,Distance> operator++(int);
+ </pre>
+<p>(that is, remove the `&').</p>
+<hr>
+<a name="261"><h3>261. Missing description of <tt>istream_iterator::operator!=</tt>
+</h3></a><p>
+<b>Section:</b> 24.5.1.2 <a href="lib-iterators.html#lib.istream.iterator.ops"> [lib.istream.iterator.ops]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 27 Aug 2000</p>
+<p>
+24.5.1, p3 lists the synopsis for
+</p>
+
+<pre>
+ template <class T, class charT, class traits, class Distance>
+ bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
+ const istream_iterator<T,charT,traits,Distance>& y);
+</pre>
+
+<p>
+but there is no description of what the operator does (i.e., no Effects
+or Returns clause) in 24.5.1.2.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Add paragraph 7 to the end of section 24.5.1.2 with the following text:
+</p>
+
+<pre>
+ template <class T, class charT, class traits, class Distance>
+ bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
+ const istream_iterator<T,charT,traits,Distance>& y);
+</pre>
+
+<p>-7- Returns: !(x == y).</p>
+<hr>
+<a name="262"><h3>262. Bitmask operator ~ specified incorrectly</h3></a><p>
+<b>Section:</b> 17.3.2.1.2 <a href="lib-intro.html#lib.bitmask.types"> [lib.bitmask.types]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Beman Dawes <b>Date:</b> 03 Sep 2000</p>
+<p>
+The ~ operation should be applied after the cast to int_type.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Change 17.3.2.1.2 [lib.bitmask.types] operator~ from:
+</p>
+
+<pre>
+ bitmask operator~ ( bitmask X )
+ { return static_cast< bitmask>(static_cast<int_type>(~ X)); }
+</pre>
+
+<p>
+to:
+</p>
+
+<pre>
+ bitmask operator~ ( bitmask X )
+ { return static_cast< bitmask>(~static_cast<int_type>(X)); }
+</pre>
+<hr>
+<a name="263"><h3>263. Severe restriction on <tt>basic_string</tt> reference counting</h3></a><p>
+<b>Section:</b> 21.3 <a href="lib-strings.html#lib.basic.string"> [lib.basic.string]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Kevlin Henney <b>Date:</b> 04 Sep 2000</p>
+<p>
+The note in paragraph 6 suggests that the invalidation rules for
+references, pointers, and iterators in paragraph 5 permit a reference-
+counted implementation (actually, according to paragraph 6, they permit
+a "reference counted implementation", but this is a minor editorial fix).
+</p>
+
+<p>
+However, the last sub-bullet is so worded as to make a reference-counted
+implementation unviable. In the following example none of the
+conditions for iterator invalidation are satisfied:
+</p>
+
+<pre>
+ // first example: "*******************" should be printed twice
+ string original = "some arbitrary text", copy = original;
+ const string & alias = original;
+
+ string::const_iterator i = alias.begin(), e = alias.end();
+ for(string::iterator j = original.begin(); j != original.end(); ++j)
+ *j = '*';
+ while(i != e)
+ cout << *i++;
+ cout << endl;
+ cout << original << endl;
+</pre>
+
+<p>
+Similarly, in the following example:
+</p>
+
+<pre>
+ // second example: "some arbitrary text" should be printed out
+ string original = "some arbitrary text", copy = original;
+ const string & alias = original;
+
+ string::const_iterator i = alias.begin();
+ original.begin();
+ while(i != alias.end())
+ cout << *i++;
+</pre>
+
+<p>
+I have tested this on three string implementations, two of which were
+reference counted. The reference-counted implementations gave
+"surprising behavior" because they invalidated iterators on
+the first call to non-const begin since construction. The current
+wording does not permit such invalidation because it does not take
+into account the first call since construction, only the first call
+since various member and non-member function calls.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>
+Change the following sentence in 21.3 paragraph 5 from
+</p>
+
+<blockquote>
+ Subsequent to any of the above uses except the forms of insert() and
+ erase() which return iterators, the first call to non-const member
+ functions operator[](), at(), begin(), rbegin(), end(), or rend().
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+ Following construction or any of the above uses, except the forms of
+ insert() and erase() that return iterators, the first call to non-
+ const member functions operator[](), at(), begin(), rbegin(), end(),
+ or rend().
+</blockquote>
+<hr>
+<a name="265"><h3>265. std::pair::pair() effects overly restrictive</h3></a><p>
+<b>Section:</b> 20.2.2 <a href="lib-utilities.html#lib.pairs"> [lib.pairs]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 11 Sep 2000</p>
+<p>
+I don't see any requirements on the types of the elements of the
+std::pair container in 20.2.2. From the descriptions of the member
+functions it appears that they must at least satisfy the requirements of
+20.1.3 [lib.copyconstructible] and 20.1.4 [lib.default.con.req], and in
+the case of the [in]equality operators also the requirements of 20.1.1
+[lib.equalitycomparable] and 20.1.2 [lib.lessthancomparable].
+</p>
+
+<p>
+I believe that the the CopyConstructible requirement is unnecessary in
+the case of 20.2.2, p2.
+</p>
+<p><b>Proposed resolution:</b></p>
+<p>Change the Effects clause in 20.2.2, p2 from</p>
+
+<blockquote>
+-2- <b>Effects</b>: Initializes its members as if implemented: <tt> pair() :
+first(T1()), second(T2()) {} </tt>
+</blockquote>
+
+<p>to</p>
+
+<blockquote>
+-2- <b>Effects</b>: Initializes its members as if implemented: <tt> pair() :
+first(), second() {} </tt>
+</blockquote>
+<p><b>Rationale:</b></p>
+<p>The existing specification of pair's constructor appears to be a
+historical artifact: there was concern that pair's members be properly
+zero-initialized when they are built-in types. At one time there was
+uncertainty about whether they would be zero-initialized if the
+default constructor was written the obvious way. This has been
+clarified by core issue 178, and there is no longer any doubt that
+the straightforward implementation is correct.</p>
+<hr>
+<a name="268"><h3>268. Typo in locale synopsis</h3></a><p>
+<b>Section:</b> 22.1.1 <a href="lib-locales.html#lib.locale"> [lib.locale]</a> <b>Status:</b> <a href="lwg-active.html#DR">DR</a> <b>Submitter:</b> Martin Sebor <b>Date:</b> 5 Oct 2000</p>
+<p>The synopsis of the class std::locale in 22.1.1 contains two typos:
+the semicolons after the declarations of the default ctor
+locale::locale() and the copy ctor locale::locale(const locale&)
+are missing.</p>
+<p><b>Proposed resolution:</b></p>
+<p>Add the missing semicolons, i.e., change</p>
+
+<pre>
+ // construct/copy/destroy:
+ locale() throw()
+ locale(const locale& other) throw()
+</pre>
+
+<p>in the synopsis in 22.1.1 to</p>
+
+<pre>
+ // construct/copy/destroy:
+ locale() throw();
+ locale(const locale& other) throw();
+</pre>
+<p>----- End of document -----</p>
+</body>
+</html>
--- /dev/null
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
+<html>
+<head>
+ <meta NAME="AUTHOR" CONTENT="pme@gcc.gnu.org (Phil Edwards)">
+ <meta NAME="KEYWORDS" CONTENT="libstdc++, libstdc++-v3, GCC, g++, STL, SGI">
+ <meta NAME="DESCRIPTION" CONTENT="SGI extensions preserved in libstdc++-v3.">
+ <meta NAME="GENERATOR" CONTENT="vi and eight fingers">
+ <title>SGI extensions to the library in libstdc++-v3</title>
+<link REL=StyleSheet HREF="lib3styles.css">
+<!-- $Id: explanations.html,v 1.2 2001/09/17 23:24:38 pme Exp $ -->
+</head>
+<body>
+
+<h1 CLASS="centered"><a name="top">SGI extensions to the library in
+libstdc++-v3</a></h1>
+
+<p>This page describes the extensions that SGI made to their version of the
+ STL subset of the Standard C++ Library. For a time we
+ <a href="../faq/index.html#5_3">tracked and imported changes and updates
+ from most of the SGI STL</a>, up through their (apparently) final release.
+ Their extensions were mostly preserved.
+</p>
+
+<p>They are listed according to the chapters of the library that they
+ extend (see <a href="../documentation.html#3">the chapter-specific notes</a>
+ for a description). Not every chapter may have extensions, and the
+ extensions may come and go. Also, this page is incomplete because the
+ author is pressed for time. Check back often; the latest change was on
+ $Date$ (UTC).
+</p>
+
+<p>Descriptions range from the scanty to the verbose. You should also check
+ the <a href="../documentation.html#4">generated documentation</a> for notes
+ and comments, especially for entries marked with '*'. For more complete
+ doumentation, see the SGI website. For <em>really</em> complete
+ documentation, buy a copy of Matt Austern's book. *grin*
+</p>
+
+<p>Back to the <a href="howto.html">libstdc++-v3 extensions</a>.
+
+
+<!-- ####################################################### -->
+<hr>
+<a name="ch20"><h3>Chapter 20</h3></a>
+<p>The <functional> header contains many additional functors and
+ helper functions, extending section 20.3. They are implemented in the
+ file stl_function.h:
+ <ul>
+ <li><code>identity_element</code> for addition and multiplication. *
+ <li>The functor <code>identity</code>, whose op() returns the argument
+ unchanged. *
+ <li>Composition functors <code>unary_function</code> and
+ <code>binary_function</code>, and their helpers <code>compose1</code>
+ and <code>compose2</code>. *
+ <li><code>select1st</code> and <code>select2nd</code>, to strip pairs. *
+ <li><code>project1st</code> and <code>project2nd</code>. *
+ <li>A set of functors/functions which always return the same result. They
+ are <code>constant_void_fun, constant_binary_fun, constant_unary_fun,
+ constant0, constant1, and constant2. *
+ <li>The class <code>subtractive_rng</code>. *
+ <li>mem_fun adaptor helpers mem_fun1 and mem_fun1_ref are provided for
+ backwards compatibility.
+</ul></p>
+<p>20.4.3 is extended with a special version of
+ <code>get_temporary_buffer</code> taking a second argument. The argument
+ is a pointer, which is ignored, but can be used to specify the template
+ type (instead of using explicit function template arguments like the
+ standard version does). That is, in addition to
+ <pre>
+ get_temporary_buffer<int>(5);</pre>
+ you can also use
+ <pre>
+ get_temporary_buffer(5, (int*)0);</pre>
+</p>
+<p>A class <code>temporary_buffer</code> is given in stl_tempbuf.h. *
+</p>
+<p>The specialized algorithms of section 20.4.4 are extended with
+ <code>uninitialized_copy_n</code>. *
+</p>
+<p>Return <a href="howto.html">to the main extensions page</a> or
+ <a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
+</p>
+
+
+<hr>
+<a name="ch23"><h3>Chapter 23</h3></a>
+<p>A few extensions and nods to backwards-compatability have been made with
+ containers. Those dealing with older SGI-style allocators are dealt with
+ elsewhere. The remaining ones all deal with bits:
+</p>
+<p>The old pre-standard <code>bit_vector</code> class is present for
+ backwards compatibility. It is simply a typedef for the
+ <code>vector<bool></code> specialization.
+</p>
+<p>The <code>bitset</code> class has a number of extensions, described in the
+ rest of this item. First, we'll mention that this implementation of
+ <code>bitset<N></code> is specialized for cases where N number of
+ bits will fit into a single word of storage. If your choice of N is
+ within that range (<=32 on i686-pc-linux-gnu, for example), then all
+ of the operations will be faster.
+</p>
+<p>There are
+ versions of single-bit test, set, reset, and flip member functions which
+ do no range-checking. If we call them member functions of an instantiation
+ of "bitset<N>," then their names and signatures are:
+ <pre>
+ bitset<N>& _Unchecked_set (size_t pos);
+ bitset<N>& _Unchecked_set (size_t pos, int val);
+ bitset<N>& _Unchecked_reset (size_t pos);
+ bitset<N>& _Unchecked_flip (size_t pos);
+ bool _Unchecked_test (size_t pos);</pre>
+ Note that these may in fact be removed in the future, although we have
+ no present plans to do so (and there doesn't seem to be any immediate
+ reason to).
+</p>
+<p>
+ The semantics of member function <code>operator[]</code> are not specified
+ in the C++ standard. A long-standing defect report calls for sensible
+ obvious semantics, which are already implemented here: <code>op[]</code>
+ on a const bitset returns a bool, and for a non-const bitset returns a
+ <code>reference</code> (a nested type). However, this implementation does
+ no range-checking on the index argument, which is in keeping with other
+ containers' <code>op[]</code> requirements. The defect report's proposed
+ resolution calls for range-checking to be done. We'll just wait and see...
+</p>
+<p>Finally, two additional searching functions have been added. They return
+ the index of the first "on" bit, and the index of the first
+ "on" bit that is after <code>prev</code>, respectively:
+ <pre>
+ size_t _Find_first() const;
+ size_t _Find_next (size_t prev) const;</pre>
+ The same caveat given for the _Unchecked_* functions applies here also.
+</p>
+<p>Return <a href="howto.html">to the main extensions page</a> or
+ <a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
+</p>
+
+
+<hr>
+<a name="ch24"><h3>Chapter 24</h3></a>
+<p>24.3.2 describes <code>struct iterator</code>, which didn't exist in the
+ original HP STL implementation (the language wasn't rich enough at the
+ time). For backwards compatibility, base classes are provided which
+ declare the same nested typedefs:
+ <ul>
+ <li>input_iterator
+ <li>output_iterator
+ <li>forward_iterator
+ <li>bidirectional_iterator
+ <li>random_access_iterator
+ </ul>
+</p>
+<p>24.3.4 describes iterator operation <code>distance</code>, which takes
+ two iterators and returns a result. It is extended by another signature
+ which takes two iterators and a reference to a result. The result is
+ modified, and the function returns nothing.
+</p>
+<p>Return <a href="howto.html">to the main extensions page</a> or
+ <a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
+</p>
+
+
+<hr>
+<a name="ch25"><h3>Chapter 25</h3></a>
+<p>25.1.6 (count, count_if) is extended with two more versions of count
+ and count_if. The standard versions return their results. The
+ additional signatures return void, but take a final parameter by
+ reference to which they assign their results, e.g.,
+ <pre>
+ void count (first, last, value, n);</pre>
+</p>
+<p>25.2 (mutating algorithms) is extended with two families of signatures,
+ random_sample and random_sample_n.
+</p>
+<p>25.2.1 (copy) is extended with
+ <pre>
+ copy_n (_InputIter first, _Size count, _OutputIter result);</pre>
+ which copies the first 'count' elements at 'first' into 'result'.
+</p>
+<p>25.3 (sorting 'n' heaps 'n' stuff) is extended with some helper
+ predicates. Look in the doxygen-generated pages for notes on these.
+ <ul>
+ <li><code>is_heap</code> tests whether or not a range is a heap.
+ <li><code>is_sorted</code> tests whether or not a range is sorted in
+ nondescending order.
+ </ul>
+</p>
+<p>25.3.8 (lexigraphical_compare) is extended with
+ <pre>
+ lexicographical_compare_3way(_InputIter1 first1, _InputIter1 last1,
+ _InputIter2 first2, _InputIter2 last2)</pre>
+ which does... what?
+</p>
+<p>Return <a href="howto.html">to the main extensions page</a> or
+ <a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
+</p>
+
+
+<hr>
+<a name="ch26"><h3>Chapter 26</h3></a>
+<p>26.4, the generalized numeric operations such as accumulate, are extended
+ with the following functions:
+ <pre>
+ power (x, n);
+ power (x, n, moniod_operation);</pre>
+ Returns, in FORTRAN syntax, "x ** n" where n>=0. In the
+ case of n == 0, returns the <a href="#ch20">identity element</a> for the
+ monoid operation. The two-argument signature uses multiplication (for
+ a true "power" implementation), but addition is supported as well.
+ The operation functor must be associative.
+</p>
+<p>The <code>iota</code> function wins the award for Extension With the
+ Coolest Name. It "assigns sequentially increasing values to a range.
+ That is, it assigns value to *first, value + 1 to *(first + 1) and so
+ on." Quoted from SGI documentation.
+ <pre>
+ void iota(_ForwardIter first, _ForwardIter last, _Tp value);</pre>
+</p>
+<p>Return <a href="howto.html">to the main extensions page</a> or
+ <a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
+</p>
+
+
+<!-- ####################################################### -->
+
+<hr>
+<P CLASS="fineprint"><em>
+$Id: explanations.html,v 1.2 2001/09/17 23:24:38 pme Exp $
+</em></p>
+
+
+</body>
+</html>
** Locations of "the most recent snapshot is the Nth" text are
** answers 1_1, 1_4, 4_1, 5_6.
-->
-<!-- $Id: index.html,v 1.10 2001/07/18 21:37:06 pme Exp $ -->
+<!-- $Id: index.html,v 1.11 2001/09/17 23:24:40 pme Exp $ -->
</head>
<body>
the mailing list or look through recent archives. The RELEASE-
NOTES and BUGS files are generally kept up-to-date.</em>
+ <p>For 3.0.1, the most common "bug" is an apparently missing
+ "<code>../</code>" in include/Makefile, resulting in files
+ like gthr.h and gthr-single.h not being found.
+ </p>
+ <p>Please read
+ <a href="http://gcc.gnu.org/install/configure.html">the configuration
+ instructions for GCC</a>,
+ specifically the part about configuring in a seperate build directory,
+ and how strongly recommended it is. Building in the source directory
+ is fragile, is rarely tested, and tends to break, as in this case.
+ Work has already gone into the source tree to make this less painful
+ for the next release.
+ </p>
+ <p><strong>Please do not report this as a bug. We know about it.</strong>
+ Reporting this -- or any other problem that's already been fixed --
+ hinders the development of GCC, because we have to take time to
+ respond to your report. Thank you.
+ </p>
+
<h2><a name="4_1">4.1 What works already?</a></h2>
<p>This is a verbatim clip from the "Status" section
of the RELEASE-NOTES for the latest snapshot.
libstdc++. Some of that is already happening, see 4.2. Some of
those changes are being predicted by the library maintainers, and
we add code to the library based on what the current proposed
- resolution specifies.
+ resolution specifies. Those additions are listed in
+ <a href="../ext/howto.html#5">the extensions page</a>.
</p>
<li><p>Performance tuning. Lots of performance tuning. This too is
already underway for post-3.0 releases, starting with memory
<P CLASS="fineprint"><em>
Comments and suggestions are welcome, and may be sent to
<a href="mailto:libstdc++@gcc.gnu.org">the mailing list</a>.
-<br> $Id: index.html,v 1.10 2001/07/18 21:37:06 pme Exp $
+<br> $Id: index.html,v 1.11 2001/09/17 23:24:40 pme Exp $
</em></p>
mailing list or look through recent archives. The RELEASE- NOTES and
BUGS files are generally kept up-to-date.
+ For 3.0.1, the most common "bug" is an apparently missing "../" in
+ include/Makefile, resulting in files like gthr.h and gthr-single.h not
+ being found.
+
+ Please read [58]the configuration instructions for GCC, specifically
+ the part about configuring in a seperate build directory, and how
+ strongly recommended it is. Building in the source directory is
+ fragile, is rarely tested, and tends to break, as in this case. Work
+ has already gone into the source tree to make this less painful for
+ the next release.
+
+ Please do not report this as a bug. We know about it. Reporting this
+ -- or any other problem that's already been fixed -- hinders the
+ development of GCC, because we have to take time to respond to your
+ report. Thank you.
+
4.1 What works already?
This is a verbatim clip from the "Status" section of the RELEASE-NOTES
4.3 Bugs in the C++ language/lib specification
- Yes, unfortunately, there are some. In a [58]message to the list,
+ Yes, unfortunately, there are some. In a [59]message to the list,
Nathan Myers announced that he has started a list of problems in the
ISO C++ Standard itself, especially with regard to the chapters that
- concern the library. The list itself is [59]posted on his website.
+ concern the library. The list itself is [60]posted on his website.
Developers who are having problems interpreting the Standard may wish
to consult his notes.
For those people who are not part of the ISO Library Group (i.e.,
nearly all of us needing to read this page in the first place :-), a
- public list of the library defects is occasionally published [60]here.
+ public list of the library defects is occasionally published [61]here.
_________________________________________________________________
4.4 Things in libstdc++ that look like bugs
same namespace as other comparison functions (e.g., 'using' them and
the <iterator> header), then you will suddenly be faced with huge
numbers of ambiguity errors. This was discussed on the -v3 list;
- Nathan Myers [61]sums things up here.
+ Nathan Myers [62]sums things up here.
The g++-3 headers are not ours
If you have found an extremely broken header file which is causing
problems for you, look carefully before submitting a "high" priority
bug report (which you probably shouldn't do anyhow; see the last
- paragraph of the page describing [62]the GCC bug database).
+ paragraph of the page describing [63]the GCC bug database).
If the headers are in ${prefix}/include/g++-3, then you are using the
old libstdc++-v2 library, which is nonstandard and unmaintained. Do
Currently our header files are installed in ${prefix}/include/g++-v3
(see the 'v'?). This may change with the next release of GCC, as it
- may be too confusing, but [63]the question has not yet been decided.
+ may be too confusing, but [64]the question has not yet been decided.
glibc If you're on a GNU/Linux system and have just upgraded to glibc
2.2, but are still using gcc 2.95.2, then you should have read the
http://clisp.cons.org/~haible/gccinclude-glibc-2.2-compat.diff
- Note that 2.95.x shipped with the [64]old v2 library which is no
+ Note that 2.95.x shipped with the [65]old v2 library which is no
longer maintained. Also note that gcc 2.95.3 fixes this problem, but
requires a separate patch for libstdc++-v3.
visibility, or you just plain forgot, etc).
More information, including how to optionally enable/disable the
- checks, is available [65]here.
+ checks, is available [66]here.
_________________________________________________________________
4.5 Aw, that's easy to fix!
If you have found a bug in the library and you think you have a
working fix, then send it in! The main GCC site has a page on
- [66]submitting patches that covers the procedure, but for libstdc++
+ [67]submitting patches that covers the procedure, but for libstdc++
you should also send the patch to our mailing list in addition to the
- GCC patches mailing list. The libstdc++ [67]contributors' page also
+ GCC patches mailing list. The libstdc++ [68]contributors' page also
talks about how to submit patches.
In addition to the description, the patch, and the ChangeLog entry, it
is a Good Thing if you can additionally create a small test program to
test for the presence of the bug that your patch fixes. Bugs have a
way of being reintroduced; if an old bug creeps back in, it will be
- caught immediately by the [68]testsuite -- but only if such a test
+ caught immediately by the [69]testsuite -- but only if such a test
exists.
_________________________________________________________________
libstdc++. Some of that is already happening, see 4.2. Some of
those changes are being predicted by the library maintainers, and
we add code to the library based on what the current proposed
- resolution specifies.
+ resolution specifies. Those additions are listed in [70]the
+ extensions page.
2. Performance tuning. Lots of performance tuning. This too is
already underway for post-3.0 releases, starting with memory
expansion in container classes and buffer usage in synchronized
type from C99.) Bugfixes and rewrites (to improve or fix thread
safety, for instance) will of course be a continuing task.
- [69]This question about the next libstdc++ prompted some brief but
- interesting [70]speculation.
+ [71]This question about the next libstdc++ prompted some brief but
+ interesting [72]speculation.
_________________________________________________________________
5.3 What about the STL from SGI?
- The [71]STL from SGI, version 3.3, was the most recent merge of the
+ The [73]STL from SGI, version 3.3, was the most recent merge of the
STL codebase. The code in libstdc++ contains many fixes and changes,
and it is very likely that the SGI code is no longer under active
development. We expect that no future merges will take place.
#include <ext/hash_map>
- Extensions to the library have [72]their own page.
+ Extensions to the library have [74]their own page.
_________________________________________________________________
5.5 [removed]
This is assuming that your idea of "multithreaded" is the same as
ours... The general question of multithreading and libstdc++-v3 is
- addressed in the chapter-specific advice for [73]Library Introduction.
- Threadsafe containers are covered in more detail in [74]the Received
+ addressed in the chapter-specific advice for [75]Library Introduction.
+ Threadsafe containers are covered in more detail in [76]the Received
Wisdom section on containers.
_________________________________________________________________
their two-meeting commitment for voting rights, may get a copy of the
standard from their respective national standards organization. In the
USA, this national standards organization is ANSI and their website is
- right [75]here. (And if you've already registered with them, clicking
- this link will take you to directly to the place where you can [76]buy
+ right [77]here. (And if you've already registered with them, clicking
+ this link will take you to directly to the place where you can [78]buy
the standard on-line.
- Who is your country's member body? Visit the [77]ISO homepage and find
+ Who is your country's member body? Visit the [79]ISO homepage and find
out!
_________________________________________________________________
- Comments and suggestions are welcome, and may be sent to [78]the
+ Comments and suggestions are welcome, and may be sent to [80]the
mailing list.
- $Id: index.html,v 1.10 2001/07/18 21:37:06 pme Exp $
+ $Id: index.html,v 1.11 2001/09/17 23:24:40 pme Exp $
References
55. http://www.gnu.org/software/cvs/cvs.html
56. http://www.cvshome.org/
57. http://gcc.gnu.org/ml/libstdc++/2000-12/msg00279.html
- 58. http://gcc.gnu.org/ml/libstdc++/1998/msg00006.html
- 59. http://www.cantrip.org/draft-bugs.txt
- 60. http://anubis.dkuug.dk/jtc1/sc22/wg21/
- 61. http://gcc.gnu.org/ml/libstdc++/2001-01/msg00247.html
- 62. http://gcc.gnu.org/gnatswrite.html
- 63. http://gcc.gnu.org/ml/gcc/2000-10/msg00732.html
- 64. ../faq/index.html#4_4_interface
- 65. ../19_diagnostics/howto.html#3
- 66. http://gcc.gnu.org/contribute.html
- 67. ../17_intro/contribute.html
- 68. ../faq/index.html#2_4
- 69. http://gcc.gnu.org/ml/libstdc++/1999/msg00080.html
- 70. http://gcc.gnu.org/ml/libstdc++/1999/msg00084.html
- 71. http://www.sgi.com/Technology/STL/
- 72. ../ext/howto.html
- 73. http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#3
- 74. http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html
- 75. http://www.ansi.org/
- 76. http://webstore.ansi.org/ansidocstore/product.asp?sku=ISO%2FIEC+14882%2D1998
- 77. http://www.iso.ch/
- 78. mailto:libstdc++@gcc.gnu.org
+ 58. http://gcc.gnu.org/install/configure.html
+ 59. http://gcc.gnu.org/ml/libstdc++/1998/msg00006.html
+ 60. http://www.cantrip.org/draft-bugs.txt
+ 61. http://anubis.dkuug.dk/jtc1/sc22/wg21/
+ 62. http://gcc.gnu.org/ml/libstdc++/2001-01/msg00247.html
+ 63. http://gcc.gnu.org/gnatswrite.html
+ 64. http://gcc.gnu.org/ml/gcc/2000-10/msg00732.html
+ 65. ../faq/index.html#4_4_interface
+ 66. ../19_diagnostics/howto.html#3
+ 67. http://gcc.gnu.org/contribute.html
+ 68. ../17_intro/contribute.html
+ 69. ../faq/index.html#2_4
+ 70. ../ext/howto.html#5
+ 71. http://gcc.gnu.org/ml/libstdc++/1999/msg00080.html
+ 72. http://gcc.gnu.org/ml/libstdc++/1999/msg00084.html
+ 73. http://www.sgi.com/Technology/STL/
+ 74. ../ext/howto.html
+ 75. http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#3
+ 76. http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html
+ 77. http://www.ansi.org/
+ 78. http://webstore.ansi.org/ansidocstore/product.asp?sku=ISO%2FIEC+14882%2D1998
+ 79. http://www.iso.ch/
+ 80. mailto:libstdc++@gcc.gnu.org
{
public:
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
- // Can't do exception(_msg) as defined in 27.4.2.1.1
+ //48. Use of non-existent exception constructor
explicit
failure(const string& __str) throw();
ios_base();
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+ //50. Copy constructor and assignment operator of ios_base
private:
ios_base(const ios_base&);
__in.width(0);
}
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
-// 2000-02-01 Number to be determined
+//211. operator>>(istream&, string&) doesn't set failbit
if (!__extracted)
__in.setstate (ios_base::failbit);
#endif
{ return do_get(__in, __end, __io, __err, __v); }
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+ //XXX. What number?
iter_type
get(iter_type __in, iter_type __end, ios_base& __io,
ios_base::iostate& __err, short& __v) const
do_get(iter_type, iter_type, ios_base&, ios_base::iostate&, bool&) const;
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+ //XXX. What number?
virtual iter_type
do_get(iter_type, iter_type, ios_base&, ios_base::iostate&, short&) const;
virtual iter_type
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
// NB: This is an unresolved library defect #17
+ //17. Bad bool parsing
template<typename _CharT, typename _InIter>
_InIter
num_get<_CharT, _InIter>::
#endif
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+ //XXX. Which number? Presumably same as in locale_facets.h...
template<typename _CharT, typename _InIter>
_InIter
num_get<_CharT, _InIter>::
typedef basic_ostream<_CharT, _Traits> __ostream_type;
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
// 167. Improper use of traits_type::length()
+// Note that this is only in 'Review' status.
typedef char_traits<char> __ctraits_type;
#endif
typename __ostream_type::sentry __cerb(__out);
// individual bits. This allows us to specialize _Base_bitset for the
// important special case where the bitset is only a single word.
-// The C++ standard does not define the precise semantics of operator[].
-// In this implementation the const version of operator[] is equivalent
-// to test(), except that it does no range checking. The non-const version
-// returns a reference to a bit, again without doing any range checking.
-
#include <bits/std_cstddef.h> // for size_t
#include <bits/std_cstring.h> // for memset
// element access:
//for b[i];
+ // _GLIBCPP_RESOLVE_LIB_DEFECTS Note that this implementation already
+ // resolves DR 11 (items 1 and 2), but does not do the range-checking
+ // required by that DR's resolution. -pme
reference operator[](size_t __pos) { return reference(*this,__pos); }
bool operator[](size_t __pos) const { return _Unchecked_test(__pos); }
class ostreambuf_iterator;
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
- // Not included.
+ // Not included. (??? Apparently no LWG number?)
class ios_base;
#endif
private:
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
- // Not defined.
+ // Not defined. (Side effect of DR 50.)
__istream_type&
operator=(const __istream_type&);
#pragma GCC system_header
-#ifndef _CPP_BITS_STL_TREE_H
#include <bits/stl_tree.h>
-#endif
#include <bits/stl_map.h>
#include <bits/stl_multimap.h>
private:
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
- // Not defined.
+ // Not defined. (Side effect of DR 50.)
__ostream_type&
operator=(const __ostream_type&);
#pragma GCC system_header
-#ifndef _CPP_BITS_STL_TREE_H /* XXX is this guard needed? */
#include <bits/stl_tree.h>
-#endif
#include <bits/stl_set.h>
#include <bits/stl_multiset.h>
#endif
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+ // Side effect of DR 50.
private:
basic_streambuf(const __streambuf_type&);
* purpose. It is provided "as is" without express or implied warranty.
*/
-/* NOTE: This is an internal header file, included by other STL headers.
- * You should not attempt to use it directly.
+/** @file stl_function.h
+ * This is an internal header file, included by other STL headers. You
+ * should not attempt to use it directly.
*/
#ifndef __SGI_STL_INTERNAL_FUNCTION_H
namespace std
{
-
+// 20.3.1 base classes
+/** @defgroup s20_3_1_base Functor Base Classes
+ * Function objects, or @e functors, are objects with an @c operator()
+ * defined and accessible. They can be passed as arguments to algorithm
+ * templates and used in place of a function pointer. Not only is the
+ * resulting expressiveness of the library increased, but the generated
+ * code can be more efficient than what you might write by hand. When we
+ * refer to "functors," then, generally we include function pointers in
+ * the description as well.
+ *
+ * Often, functors are only created as temporaries passed to algorithm
+ * calls, rather than being created as named variables.
+ *
+ * Two examples taken from the standard itself follow. To perform a
+ * by-element addition of two vectors @c a and @c b containing @c double,
+ * and put the result in @c a, use
+ * \code
+ * transform (a.begin(), a.end(), b.begin(), a.begin(), plus<double>());
+ * \endcode
+ * To negate every element in @c a, use
+ * \code
+ * transform(a.begin(), a.end(), a.begin(), negate<double>());
+ * \endcode
+ * The addition and negation functions will be inlined directly.
+ *
+ * The standard functiors are derived from structs named @c unary_function
+ * and @c binary_function. These two classes contain nothing but typedefs,
+ * to aid in generic (template) programming. If you write your own
+ * functors, you might consider doing the same.
+ *
+ * @{
+*/
+/**
+ * This is one of the @link s20_3_1_base functor base classes @endlink.
+*/
template <class _Arg, class _Result>
struct unary_function {
- typedef _Arg argument_type;
- typedef _Result result_type;
+ typedef _Arg argument_type; ///< @c argument_type is the type of the argument (no surprises here)
+ typedef _Result result_type; ///< @c result_type is the return type
};
+/**
+ * This is one of the @link s20_3_1_base functor base classes @endlink.
+*/
template <class _Arg1, class _Arg2, class _Result>
struct binary_function {
- typedef _Arg1 first_argument_type;
- typedef _Arg2 second_argument_type;
- typedef _Result result_type;
+ typedef _Arg1 first_argument_type; ///< the type of the first argument (no surprises here)
+ typedef _Arg2 second_argument_type; ///< the type of the second argument
+ typedef _Result result_type; ///< type of the return type
};
+/** @} */
+// 20.3.2 arithmetic
+/** @defgroup s20_3_2_arithmetic Arithmetic Classes
+ * Because basic math often needs to be done during an algorithm, the library
+ * provides functors for those operations. See the documentation for
+ * @link s20_3_1_base the base classes @endlink for examples of their use.
+ *
+ * @{
+*/
+/// One of the @link s20_3_2_arithmetic math functors @endlink.
template <class _Tp>
struct plus : public binary_function<_Tp,_Tp,_Tp> {
_Tp operator()(const _Tp& __x, const _Tp& __y) const { return __x + __y; }
};
+/// One of the @link s20_3_2_arithmetic math functors @endlink.
template <class _Tp>
struct minus : public binary_function<_Tp,_Tp,_Tp> {
_Tp operator()(const _Tp& __x, const _Tp& __y) const { return __x - __y; }
};
+/// One of the @link s20_3_2_arithmetic math functors @endlink.
template <class _Tp>
struct multiplies : public binary_function<_Tp,_Tp,_Tp> {
_Tp operator()(const _Tp& __x, const _Tp& __y) const { return __x * __y; }
};
+/// One of the @link s20_3_2_arithmetic math functors @endlink.
template <class _Tp>
struct divides : public binary_function<_Tp,_Tp,_Tp> {
_Tp operator()(const _Tp& __x, const _Tp& __y) const { return __x / __y; }
};
-// identity_element (not part of the C++ standard).
-
-template <class _Tp> inline _Tp identity_element(plus<_Tp>) {
- return _Tp(0);
-}
-template <class _Tp> inline _Tp identity_element(multiplies<_Tp>) {
- return _Tp(1);
-}
-
+/// One of the @link s20_3_2_arithmetic math functors @endlink.
template <class _Tp>
struct modulus : public binary_function<_Tp,_Tp,_Tp>
{
_Tp operator()(const _Tp& __x, const _Tp& __y) const { return __x % __y; }
};
+/// One of the @link s20_3_2_arithmetic math functors @endlink.
template <class _Tp>
struct negate : public unary_function<_Tp,_Tp>
{
_Tp operator()(const _Tp& __x) const { return -__x; }
};
+/** @} */
+/** The @c identity_element functions are not part of the C++ standard; SGI
+ * provided them as an extension. Its argument is an operation, and its
+ * return value is the identity element for that operation. It is overloaded
+ * for addition and multiplication, and you can overload it for your own
+ * nefarious operations.
+ *
+ * @addtogroup SGIextensions
+ * @{
+*/
+/// An \link SGIextensions SGI extension \endlink.
+template <class _Tp> inline _Tp identity_element(plus<_Tp>) {
+ return _Tp(0);
+}
+/// An \link SGIextensions SGI extension \endlink.
+template <class _Tp> inline _Tp identity_element(multiplies<_Tp>) {
+ return _Tp(1);
+}
+/** @} */
+
+// 20.3.3 comparisons
+/** @defgroup s20_3_3_comparisons Comparison Classes
+ * The library provides six wrapper functors for all the basic comparisons
+ * in C++, like @c <.
+ *
+ * @{
+*/
+/// One of the @link s20_3_3_comparisons comparison functors @endlink.
template <class _Tp>
struct equal_to : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x == __y; }
};
+/// One of the @link s20_3_3_comparisons comparison functors @endlink.
template <class _Tp>
struct not_equal_to : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x != __y; }
};
+/// One of the @link s20_3_3_comparisons comparison functors @endlink.
template <class _Tp>
struct greater : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x > __y; }
};
+/// One of the @link s20_3_3_comparisons comparison functors @endlink.
template <class _Tp>
struct less : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x < __y; }
};
+/// One of the @link s20_3_3_comparisons comparison functors @endlink.
template <class _Tp>
struct greater_equal : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x >= __y; }
};
+/// One of the @link s20_3_3_comparisons comparison functors @endlink.
template <class _Tp>
struct less_equal : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x <= __y; }
};
+/** @} */
+// 20.3.4 logical operations
+/** @defgroup s20_3_4_logical Boolean Operations Classes
+ * Here are wrapper functors for Boolean operations: @c &&, @c ||, and @c !.
+ *
+ * @{
+*/
+/// One of the @link s20_3_4_logical Boolean operations functors @endlink.
template <class _Tp>
struct logical_and : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x && __y; }
};
+/// One of the @link s20_3_4_logical Boolean operations functors @endlink.
template <class _Tp>
struct logical_or : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x || __y; }
};
+/// One of the @link s20_3_4_logical Boolean operations functors @endlink.
template <class _Tp>
struct logical_not : public unary_function<_Tp,bool>
{
bool operator()(const _Tp& __x) const { return !__x; }
};
-
+/** @} */
+
+// 20.3.5 negators
+/** @defgroup s20_3_5_negators Negators
+ * The functions @c not1 and @c not2 each take a predicate functor
+ * and return an instance of @c unary_negate or
+ * @c binary_negate, respectively. These classes are functors whose
+ * @c operator() performs the stored predicate function and then returns
+ * the negation of the result.
+ *
+ * For example, given a vector of integers and a trivial predicate,
+ * \code
+ * struct IntGreaterThanThree
+ * : public std::unary_function<int, bool>
+ * {
+ * bool operator() (int x) { return x > 3; }
+ * };
+ *
+ * std::find_if (v.begin(), v.end(), not1(IntGreaterThanThree()));
+ * \endcode
+ * The call to @c find_if will locate the first index (i) of @c v for which
+ * "!(v[i] > 3)" is true.
+ *
+ * The not1/unary_negate combination works on predicates taking a single
+ * argument. The not2/binary_negate combination works on predicates which
+ * take two arguments.
+ *
+ * @{
+*/
+/// One of the @link s20_3_5_negators negation functors @endlink.
template <class _Predicate>
class unary_negate
: public unary_function<typename _Predicate::argument_type, bool> {
}
};
+/// One of the @link s20_3_5_negators negation functors @endlink.
template <class _Predicate>
inline unary_negate<_Predicate>
not1(const _Predicate& __pred)
return unary_negate<_Predicate>(__pred);
}
+/// One of the @link s20_3_5_negators negation functors @endlink.
template <class _Predicate>
class binary_negate
: public binary_function<typename _Predicate::first_argument_type,
}
};
+/// One of the @link s20_3_5_negators negation functors @endlink.
template <class _Predicate>
inline binary_negate<_Predicate>
not2(const _Predicate& __pred)
{
return binary_negate<_Predicate>(__pred);
}
-
+/** @} */
+
+// 20.3.6 binders
+/** @defgroup s20_3_6_binder Binder Classes
+ * Binders turn functions/functors with two arguments into functors with
+ * a single argument, storing an argument to be applied later. For
+ * example, an variable @c B of type @c binder1st is constructed from a functor
+ * @c f and an argument @c x. Later, B's @c operator() is called with a
+ * single argument @c y. The return value is the value of @c f(x,y).
+ * @c B can be "called" with various arguments (y1, y2, ...) and will in
+ * turn call @c f(x,y1), @c f(x,y2), ...
+ *
+ * The function @c bind1st is provided to save some typing. It takes the
+ * function and an argument as parameters, and returns an instance of
+ * @c binder1st.
+ *
+ * The type @c binder2nd and its creator function @c bind2nd do the same
+ * thing, but the stored argument is passed as the second parameter instead
+ * of the first, e.g., @c bind2nd(std::minus<float>,1.3) will create a
+ * functor whose @c operator() accepts a floating-point number, subtracts
+ * 1.3 from it, and returns the result. (If @c bind1st had been used,
+ * the functor would perform "1.3 - x" instead.
+ *
+ * Creator-wrapper functions like @c bind1st are intended to be used in
+ * calling algorithms. Their return values will be temporary objects.
+ * (The goal is to not require you to type names like
+ * @c std::binder1st<std::plus<int>> for declaring a variable to hold the
+ * return value from @c bind1st(std::plus<int>,5).
+ *
+ * These become more useful when combined with the composition functions.
+ *
+ * @{
+*/
+/// One of the @link s20_3_6_binder binder functors @endlink.
template <class _Operation>
class binder1st
: public unary_function<typename _Operation::second_argument_type,
return op(value, __x);
}
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
- // 109. Missing binders for non-const sequence elements
+ //109. Missing binders for non-const sequence elements
typename _Operation::result_type
operator()(typename _Operation::second_argument_type& __x) const {
return op(value, __x);
#endif
};
+/// One of the @link s20_3_6_binder binder functors @endlink.
template <class _Operation, class _Tp>
inline binder1st<_Operation>
bind1st(const _Operation& __fn, const _Tp& __x)
return binder1st<_Operation>(__fn, _Arg1_type(__x));
}
+/// One of the @link s20_3_6_binder binder functors @endlink.
template <class _Operation>
class binder2nd
: public unary_function<typename _Operation::first_argument_type,
return op(__x, value);
}
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
- // 109. Missing binders for non-const sequence elements
+ //109. Missing binders for non-const sequence elements
typename _Operation::result_type
operator()(typename _Operation::first_argument_type& __x) const {
return op(__x, value);
#endif
};
+/// One of the @link s20_3_6_binder binder functors @endlink.
template <class _Operation, class _Tp>
inline binder2nd<_Operation>
bind2nd(const _Operation& __fn, const _Tp& __x)
typedef typename _Operation::second_argument_type _Arg2_type;
return binder2nd<_Operation>(__fn, _Arg2_type(__x));
}
-
-// unary_compose and binary_compose (extensions, not part of the standard).
-
+/** @} */
+
+/** As an extension to the binders, SGI provided composition functors and
+ * wrapper functions to aid in their creation. The @c unary_compose
+ * functor is constructed from two functions/functors, @c f and @c g.
+ * Calling @c operator() with a single argument @c x returns @c f(g(x)).
+ * The function @c compose1 takes the two functions and constructs a
+ * @c unary_compose variable for you.
+ *
+ * @c binary_compose is constructed from three functors, @c f, @c g1,
+ * and @c g2. Its @c operator() returns @c f(g1(x),g2(x)). The function
+ * @compose2 takes f, g1, and g2, and constructs the @c binary_compose
+ * instance for you. For example, if @c f returns an int, then
+ * \code
+ * int answer = (compose2(f,g1,g2))(x);
+ * \endcode
+ * is equivalent to
+ * \code
+ * int temp1 = g1(x);
+ * int temp2 = g2(x);
+ * int answer = f(temp1,temp2);
+ * \endcode
+ * But the first form is more compact, and can be passed around as a
+ * functor to other algorithms.
+ *
+ * @addtogroup SGIextensions
+ * @{
+*/
+/// An \link SGIextensions SGI extension \endlink.
template <class _Operation1, class _Operation2>
class unary_compose
: public unary_function<typename _Operation2::argument_type,
}
};
+/// An \link SGIextensions SGI extension \endlink.
template <class _Operation1, class _Operation2>
inline unary_compose<_Operation1,_Operation2>
compose1(const _Operation1& __fn1, const _Operation2& __fn2)
return unary_compose<_Operation1,_Operation2>(__fn1, __fn2);
}
+/// An \link SGIextensions SGI extension \endlink.
template <class _Operation1, class _Operation2, class _Operation3>
class binary_compose
: public unary_function<typename _Operation2::argument_type,
}
};
+/// An \link SGIextensions SGI extension \endlink.
template <class _Operation1, class _Operation2, class _Operation3>
inline binary_compose<_Operation1, _Operation2, _Operation3>
compose2(const _Operation1& __fn1, const _Operation2& __fn2,
return binary_compose<_Operation1,_Operation2,_Operation3>
(__fn1, __fn2, __fn3);
}
-
+/** @} */
+
+// 20.3.7 adaptors pointers functions
+/** @defgroup s20_3_7_adaptors Adaptors for pointers to functions
+ * The advantage of function objects over pointers to functions is that
+ * the objects in the standard library declare nested typedefs describing
+ * their argument and result types with uniform names (e.g., @c result_type
+ * from the base classes @c unary_function and @c binary_function).
+ * Sometimes those typedefs are required, not just optional.
+ *
+ * Adaptors are provided to turn pointers to unary (single-argument) and
+ * binary (double-argument) functions into function objects. The long-winded
+ * functor @c pointer_to_unary_function is constructed with a function
+ * pointer @c f, and its @c operator() called with argument @c x returns
+ * @c f(x). The functor @c pointer_to_binary_function does the same thing,
+ * but with a double-argument @c f and @c operator().
+ *
+ * The function @c ptr_fun takes a pointer-to-function @c f and constructs
+ * an instance of the appropriate functor.
+ *
+ * @{
+*/
+/// One of the @link s20_3_7_adaptors adaptors for function pointers @endlink.
template <class _Arg, class _Result>
class pointer_to_unary_function : public unary_function<_Arg, _Result> {
protected:
_Result operator()(_Arg __x) const { return _M_ptr(__x); }
};
+/// One of the @link s20_3_7_adaptors adaptors for function pointers @endlink.
template <class _Arg, class _Result>
inline pointer_to_unary_function<_Arg, _Result> ptr_fun(_Result (*__x)(_Arg))
{
return pointer_to_unary_function<_Arg, _Result>(__x);
}
+/// One of the @link s20_3_7_adaptors adaptors for function pointers @endlink.
template <class _Arg1, class _Arg2, class _Result>
class pointer_to_binary_function :
public binary_function<_Arg1,_Arg2,_Result> {
}
};
+/// One of the @link s20_3_7_adaptors adaptors for function pointers @endlink.
template <class _Arg1, class _Arg2, class _Result>
inline pointer_to_binary_function<_Arg1,_Arg2,_Result>
ptr_fun(_Result (*__x)(_Arg1, _Arg2)) {
return pointer_to_binary_function<_Arg1,_Arg2,_Result>(__x);
}
+/** @} */
-// identity is an extensions: it is not part of the standard.
+
+// extension documented next
template <class _Tp>
struct _Identity : public unary_function<_Tp,_Tp> {
_Tp& operator()(_Tp& __x) const { return __x; }
const _Tp& operator()(const _Tp& __x) const { return __x; }
};
+/** As an extension, SGI provided a functor called @c identity. When a
+ * functor is required but no operations are desired, this can be used as a
+ * pass-through. Its @c operator() returns its argument unchanged.
+ *
+ * @addtogroup SGIextensions
+*/
template <class _Tp> struct identity : public _Identity<_Tp> {};
-// select1st and select2nd are extensions: they are not part of the standard.
+// extension documented next
template <class _Pair>
struct _Select1st : public unary_function<_Pair, typename _Pair::first_type> {
typename _Pair::first_type& operator()(_Pair& __x) const {
}
};
+/** @c select1st and @c select2nd are extensions provided by SGI. Their
+ * @c operator()s
+ * take a @c std::pair as an argument, and return either the first member
+ * or the second member, respectively. They can be used (especially with
+ * the composition functors) to "strip" data from a sequence before
+ * performing the remainder of an algorithm.
+ *
+ * @addtogroup SGIextensions
+ * @{
+*/
+/// An \link SGIextensions SGI extension \endlink.
template <class _Pair> struct select1st : public _Select1st<_Pair> {};
+/// An \link SGIextensions SGI extension \endlink.
template <class _Pair> struct select2nd : public _Select2nd<_Pair> {};
+/** @} */
-// project1st and project2nd are extensions: they are not part of the standard
+// extension documented next
template <class _Arg1, class _Arg2>
struct _Project1st : public binary_function<_Arg1, _Arg2, _Arg1> {
_Arg1 operator()(const _Arg1& __x, const _Arg2&) const { return __x; }
_Arg2 operator()(const _Arg1&, const _Arg2& __y) const { return __y; }
};
+/** The @c operator() of the @c project1st functor takes two arbitrary
+ * arguments and returns the first one, while @c project2nd returns the
+ * second one. They are extensions provided by SGI.
+ *
+ * @addtogroup SGIextensions
+ * @{
+*/
+/// An \link SGIextensions SGI extension \endlink.
template <class _Arg1, class _Arg2>
struct project1st : public _Project1st<_Arg1, _Arg2> {};
+/// An \link SGIextensions SGI extension \endlink.
template <class _Arg1, class _Arg2>
struct project2nd : public _Project2nd<_Arg1, _Arg2> {};
+/** @} */
-// constant_void_fun, constant_unary_fun, and constant_binary_fun are
-// extensions: they are not part of the standard. (The same, of course,
-// is true of the helper functions constant0, constant1, and constant2.)
-
+// extension documented next
template <class _Result>
struct _Constant_void_fun {
typedef _Result result_type;
}
};
+/** These three functors are each constructed from a single arbitrary
+ * variable/value. Later, their @c operator()s completely ignore any
+ * arguments passed, and return the stored value.
+ * - @c constant_void_fun's @c operator() takes no arguments
+ * - @c constant_unary_fun's @c operator() takes one argument (ignored)
+ * - @c constant_binary_fun's @c operator() takes two arguments (ignored)
+ *
+ * The helper creator functions @c constant0, @c constant1, and
+ * @c constant2 each take a "result" argument and construct variables of
+ * the appropriate functor type.
+ *
+ * @addtogroup SGIextensions
+ * @{
+*/
+/// An \link SGIextensions SGI extension \endlink.
template <class _Result>
struct constant_void_fun : public _Constant_void_fun<_Result> {
constant_void_fun(const _Result& __v) : _Constant_void_fun<_Result>(__v) {}
};
-
+/// An \link SGIextensions SGI extension \endlink.
template <class _Result,
class _Argument = _Result>
struct constant_unary_fun : public _Constant_unary_fun<_Result, _Argument>
: _Constant_unary_fun<_Result, _Argument>(__v) {}
};
-
+/// An \link SGIextensions SGI extension \endlink.
template <class _Result,
class _Arg1 = _Result,
class _Arg2 = _Arg1>
: _Constant_binary_fun<_Result, _Arg1, _Arg2>(__v) {}
};
+/// An \link SGIextensions SGI extension \endlink.
template <class _Result>
inline constant_void_fun<_Result> constant0(const _Result& __val)
{
return constant_void_fun<_Result>(__val);
}
+/// An \link SGIextensions SGI extension \endlink.
template <class _Result>
inline constant_unary_fun<_Result,_Result> constant1(const _Result& __val)
{
return constant_unary_fun<_Result,_Result>(__val);
}
+/// An \link SGIextensions SGI extension \endlink.
template <class _Result>
inline constant_binary_fun<_Result,_Result,_Result>
constant2(const _Result& __val)
{
return constant_binary_fun<_Result,_Result,_Result>(__val);
}
+/** @} */
-// subtractive_rng is an extension: it is not part of the standard.
-// Note: this code assumes that int is 32 bits.
+/** The @c subtractive_rng class is documented on
+ * <a href="http://www.sgi.com/tech/stl/">SGI's site</a>.
+ * Note that this code assumes that @c int is 32 bits.
+ *
+ * @ingroup SGIextensions
+*/
class subtractive_rng : public unary_function<unsigned int, unsigned int> {
private:
unsigned int _M_table[55];
size_t _M_index1;
size_t _M_index2;
public:
+ /// Returns a number less than the argument.
unsigned int operator()(unsigned int __limit) {
_M_index1 = (_M_index1 + 1) % 55;
_M_index2 = (_M_index2 + 1) % 55;
_M_index2 = 31;
}
+ /// Ctor allowing you to initialize the seed.
subtractive_rng(unsigned int __seed) { _M_initialize(__seed); }
+ /// Default ctor; initializes its state with some number you don't see.
subtractive_rng() { _M_initialize(161803398u); }
};
-// Adaptor function objects: pointers to member functions.
-
-// There are a total of 16 = 2^4 function objects in this family.
-// (1) Member functions taking no arguments vs member functions taking
-// one argument.
-// (2) Call through pointer vs call through reference.
-// (3) Member function with void return type vs member function with
-// non-void return type.
-// (4) Const vs non-const member function.
-
-// Note that choice (3) is nothing more than a workaround: according
-// to the draft, compilers should handle void and non-void the same way.
-// This feature is not yet widely implemented, though. You can only use
-// member functions returning void if your compiler supports partial
-// specialization.
-
-// All of this complexity is in the function objects themselves. You can
-// ignore it by using the helper function mem_fun and mem_fun_ref,
-// which create whichever type of adaptor is appropriate.
-// (mem_fun1 and mem_fun1_ref are no longer part of the C++ standard,
-// but they are provided for backward compatibility.)
-
-
+// 20.3.8 adaptors pointers members
+/** @defgroup s20_3_8_memadaptors Adaptors for pointers to members
+ * There are a total of 16 = 2^4 function objects in this family.
+ * (1) Member functions taking no arguments vs member functions taking
+ * one argument.
+ * (2) Call through pointer vs call through reference.
+ * (3) Member function with void return type vs member function with
+ * non-void return type.
+ * (4) Const vs non-const member function.
+ *
+ * Note that choice (3) is nothing more than a workaround: according
+ * to the draft, compilers should handle void and non-void the same way.
+ * This feature is not yet widely implemented, though. You can only use
+ * member functions returning void if your compiler supports partial
+ * specialization.
+ *
+ * All of this complexity is in the function objects themselves. You can
+ * ignore it by using the helper function mem_fun and mem_fun_ref,
+ * which create whichever type of adaptor is appropriate.
+ * (mem_fun1 and mem_fun1_ref are no longer part of the C++ standard,
+ * but they are provided for backward compatibility.)
+ *
+ * @{
+*/
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp>
class mem_fun_t : public unary_function<_Tp*,_Ret> {
public:
_Ret (_Tp::*_M_f)();
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp>
class const_mem_fun_t : public unary_function<const _Tp*,_Ret> {
public:
_Ret (_Tp::*_M_f)() const;
};
-
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp>
class mem_fun_ref_t : public unary_function<_Tp,_Ret> {
public:
_Ret (_Tp::*_M_f)();
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp>
class const_mem_fun_ref_t : public unary_function<_Tp,_Ret> {
public:
_Ret (_Tp::*_M_f)() const;
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp, class _Arg>
class mem_fun1_t : public binary_function<_Tp*,_Arg,_Ret> {
public:
_Ret (_Tp::*_M_f)(_Arg);
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp, class _Arg>
class const_mem_fun1_t : public binary_function<const _Tp*,_Arg,_Ret> {
public:
_Ret (_Tp::*_M_f)(_Arg) const;
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp, class _Arg>
class mem_fun1_ref_t : public binary_function<_Tp,_Arg,_Ret> {
public:
_Ret (_Tp::*_M_f)(_Arg);
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Ret, class _Tp, class _Arg>
class const_mem_fun1_ref_t : public binary_function<_Tp,_Arg,_Ret> {
public:
_Ret (_Tp::*_M_f)(_Arg) const;
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp>
class mem_fun_t<void, _Tp> : public unary_function<_Tp*,void> {
public:
void (_Tp::*_M_f)();
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp>
class const_mem_fun_t<void, _Tp> : public unary_function<const _Tp*,void> {
public:
void (_Tp::*_M_f)() const;
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp>
class mem_fun_ref_t<void, _Tp> : public unary_function<_Tp,void> {
public:
void (_Tp::*_M_f)();
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp>
class const_mem_fun_ref_t<void, _Tp> : public unary_function<_Tp,void> {
public:
void (_Tp::*_M_f)() const;
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp, class _Arg>
class mem_fun1_t<void, _Tp, _Arg> : public binary_function<_Tp*,_Arg,void> {
public:
void (_Tp::*_M_f)(_Arg);
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp, class _Arg>
class const_mem_fun1_t<void, _Tp, _Arg>
: public binary_function<const _Tp*,_Arg,void> {
void (_Tp::*_M_f)(_Arg) const;
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp, class _Arg>
class mem_fun1_ref_t<void, _Tp, _Arg>
: public binary_function<_Tp,_Arg,void> {
void (_Tp::*_M_f)(_Arg);
};
+/// One of the @link s20_3_8_memadaptors adaptors for member pointers @endlink.
template <class _Tp, class _Arg>
class const_mem_fun1_ref_t<void, _Tp, _Arg>
: public binary_function<_Tp,_Arg,void> {
inline const_mem_fun1_ref_t<_Ret,_Tp,_Arg>
mem_fun1_ref(_Ret (_Tp::*__f)(_Arg) const)
{ return const_mem_fun1_ref_t<_Ret,_Tp,_Arg>(__f); }
+/** @} */
} // namespace std
return __x.first == __y.first && __x.second == __y.second;
}
-/// ...put link to onlinedocs here...
+/// http://gcc.gnu.org/onlinedocs/libstdc++/20_util/howto.html#pairlt
template <class _T1, class _T2>
inline bool operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
{
* @return A newly-constructed pair<> object of the appropriate type.
*
* The standard requires that the objects be passed by reference-to-const,
- * but LWG issue #181 says they should be passed by const value.
- */
+ * but LWG issue #181 says they should be passed by const value. We follow
+ * the LWG by default.
+*/
template <class _T1, class _T2>
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
//181. make_pair() unintended behavior
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
// 110 istreambuf_iterator::equal not const
- // NB: there is also number 111 pending on this function.
+ // NB: there is also number 111 (NAD, Future) pending on this function.
bool
equal(const istreambuf_iterator& __b) const
{
public:
// the public interface
- /** Returns an \e implementation-defined byte string; this is not
+ /** Returns an @e implementation-defined byte string; this is not
* portable between compilers! */
const char* name() const
{ return __name; }
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