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C++ Standard Library Defect Report List (Revision 20)Reference ISO/IEC IS 14882:1998(E) Also see:
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 DR, TC, or RR. See the Library Closed Issues List for issues closed as non-defects. See the Library Active Issues List for active issues and more information. The introductory material in that document also applies to this document. Revision History
Defect Reports1. C library linkage editing oversightSection: 17.4.2.2 [lib.using.linkage] Status: DR Submitter: Beman Dawes Date: 16 Nov 1997 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. Proposed resolution: Change 17.4.2.2 [lib.using.linkage] paragraph 2 from:
to:
3. Atexit registration during atexit() call is not describedSection: 18.3 [lib.support.start.term] Status: DR Submitter: Steve Clamage Date: 12 Dec 1997 We appear not to have covered all the possibilities of
exit processing with respect to
atexit registration. #include <stdlib.h> void f1() { } void f2() { atexit(f1); } int main() { atexit(f2); // the only use of f2 return 0; // for C compatibility } 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? 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. 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. If the program is valid, the standards are self-contradictory about its semantics. Example 2: (C++ only) void F() { static T t; } // type T has a destructor int main() { atexit(F); // the only use of F } 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? 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. 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. If the program is valid, the standard is self-contradictory about its semantics. 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.) I think we should resolve the situation in the whatever way the C committee decides. For Example 2, I recommend we declare the results undefined. [See reflector message lib-6500 for further discussion.] Proposed resolution: Change section 18.3/8 from: 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. to: 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. Rationale: See 99-0039/N1215, October 22, 1999, by Stephen D. Clamage for the analysis supporting to the proposed resolution. 5. String::compare specification questionableSection: 21.3.6.8 [lib.string::compare] Status: DR Submitter: Jack Reeves Date: 11 Dec 1997 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); 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. 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); 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. Proposed resolution: Replace the compare signature in 21.3 [lib.basic.string] (at the very end of the basic_string synopsis) which reads:
with:
Replace the portion of 21.3.6.8 [lib.string::compare] paragraphs 5 and 6 which read:
with:
Editors please note that in addition to splitting the signature, the third argument becomes const, matching the existing synopsis. Rationale: 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. 7. String clause minor problemsSection: 21 [lib.strings] Status: DR Submitter: Matt Austern Date: 15 Dec 1997 (1) In 21.3.5.4 [lib.string::insert], 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. (2) Several versions of basic_string::replace don't appear in the class synopsis. (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&. (4) basic_string::pop_back is missing. (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 [lib.string::compare] (6) In table 37, in section 21.1.1 [lib.char.traits.require], 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. Proposed resolution: ITEM 1: In 21.3.5.4 [lib.string::insert], change paragraph 16 to void push_back(const charT) 8. Locale::global lacks guaranteeSection: 22.1.1.5 [lib.locale.statics] Status: DR Submitter: Matt Austern Date: 24 Dec 1997 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. The intent, I think, is that it should not, but I can't find any such words anywhere. Proposed resolution: Add a sentence at the end of 22.1.1.5 [lib.locale.statics], paragraph 2:
9. Operator new(0) calls should not yield the same pointerSection: 18.4.1 [lib.new.delete] Status: DR Submitter: Steve Clamage Date: 4 Jan 1998 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.] Proposed resolution: Change the last paragraph of 3.7.3 from:
to:
Change 3.7.3.1/2, next-to-last sentence, from :
to:
5.3.4/7 currently reads:
Retain the first sentence, and delete the remainder. 18.4.1 currently has no text. Add the following:
To 18.4.1.3, add the following text:
Rationale: See 99-0040/N1216, October 22, 1999, by Stephen D. Clamage for the analysis supporting to the proposed resolution. 11. Bitset minor problemsSection: 23.3.5 [lib.template.bitset] Status: DR Submitter: Matt Austern Date: 22 Jan 1998 (1) bitset<>::operator[] is mentioned in the class synopsis (23.3.5), but it is not documented in 23.3.5.2. (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. (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. Proposed resolution: ITEMS 1 AND 2:
Rationale: The LWG believes Item 3 is not a defect. "Formatted input" implies the desired semantics. See 27.6.1.2 [lib.istream.formatted]. 13. Eos refuses to dieSection: 27.6.1.2.3 [lib.istream::extractors] Status: DR Submitter: William M. Miller Date: 3 Mar 1998 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. Proposed resolution: In 27.6.1.2.3 [lib.istream::extractors], replace "eos" with "charT()" 14. Locale::combine should be constSection: 22.1.1.3 [lib.locale.members] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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." 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. Proposed resolution: In 22.1.1 [lib.locale] and also in 22.1.1.3 [lib.locale.members], add "const" to the declaration of member combine: template <class Facet> locale combine(const locale& other) const; 15. Locale::name requirement inconsistentSection: 22.1.1.3 [lib.locale.members] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 locale::name() is described as returning a string that can be passed to a locale constructor, but there is no matching constructor. Proposed resolution: In 22.1.1.3 [lib.locale.members], paragraph 5, replace "locale(name())" with "locale(name().c_str())". 16. Bad ctype_byname<char> declSection: 22.2.1.4 [lib.locale.ctype.byname.special] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: The correct declarations for the overloaded members do_narrow and do_widen should be copied from 22.2.1.3 [lib.facet.ctype.special]. 17. Bad bool parsingSection: 22.2.2.1.2 [lib.facet.num.get.virtuals] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. // 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; 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. Proposed resolution: In 22.2.2.1.2 [lib.facet.num.get.virtuals], in the first line of paragraph 14, change "&&" to "&". Then, replace paragraphs 15 and 16 as follows:
18. Get(...bool&) omittedSection: 22.2.2.1.1 [lib.facet.num.get.members] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: Add at the beginning of 22.2.2.1.1 [lib.facet.num.get.members] another get member for bool&, copied from the entry in 22.2.2.1 [lib.locale.num.get]. 19. "Noconv" definition too vagueSection: 22.2.1.5.2 [lib.locale.codecvt.virtuals] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: Change the entry for noconv in the table under paragraph 4 in section 22.2.1.5.2 [lib.locale.codecvt.virtuals] to read:
Change the Note in paragraph 2 to normative text as follows:
20. Thousands_sep returns wrong typeSection: 22.2.3.1.2 [lib.facet.numpunct.virtuals] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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". Proposed resolution: In 22.2.3.1.2 [lib.facet.numpunct.virtuals], above paragraph 2, change "string_type" to "char_type". 21. Codecvt_byname<> instantiationsSection: 22.1.1.1.1 [lib.locale.category] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: Add in 22.1.1.1.1 [lib.locale.category] to the table captioned "Required instantiations", in the category "ctype" the lines codecvt_byname<char,char,mbstate_t>, codecvt_byname<wchar_t,char,mbstate_t> 22. Member open vs. flagsSection: 27.8.1.7 [lib.ifstream.members] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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(). Proposed resolution: In 27.8.1.7 [lib.ifstream.members] paragraph 3, and in 27.8.1.10 [lib.ofstream.members] paragraph 3, under open() effects, add a footnote:
Rationale: This may seem surprising to some users, but it's just an instance of a general rule: error flags are never cleared by the implementation. The only way error flags are are ever cleared is if the user explicitly clears them by hand. The LWG believed that preserving this general rule was important enough so that an exception shouldn't be made just for this one case. The resolution of this issue clarifies what the LWG believes to have been the original intent. 24. "do_convert" doesn't existSection: 22.2.1.5.2 [lib.locale.codecvt.virtuals] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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". Proposed resolution: In 22.2.1.5 [lib.locale.codecvt], paragraph 3, change "do_convert" to "do_in or do_out". Also, in 22.2.1.5.2 [lib.locale.codecvt.virtuals], change "do_convert()" to "do_in or do_out". 25. String operator<< uses width() value wrongSection: 21.3.7.9 [lib.string.io] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: Change 21.3.7.9 [lib.string.io] paragraph 4 from: 26. Bad sentry exampleSection: 27.6.1.1.2 [lib.istream::sentry] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 In paragraph 6, the code in the example: 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; } } ... } 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.) Proposed resolution: Remove the example above from 27.6.1.1.2 [lib.istream::sentry] paragraph 6. Rationale: 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. 27. String::erase(range) yields wrong iteratorSection: 21.3.5.5 [lib.string::erase] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: In 21.3.5.5 [lib.string::erase], paragraph 10, change:
to read
28. Ctype<char>is ambiguousSection: 22.2.1.3.2 [lib.facet.ctype.char.members] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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
This is intended to copy the value indexed from table()[] into the place identified in vec[]. Proposed resolution: Change 22.2.1.3.2 [lib.facet.ctype.char.members], paragraph 4, to read
29. Ios_base::init doesn't existSection: 27.3.1 [lib.narrow.stream.objects] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 Sections 27.3.1 [lib.narrow.stream.objects] and 27.3.2 [lib.wide.stream.objects] mention a function ios_base::init, which is not defined. Probably they mean basic_ios<>::init, defined in 27.4.4.1 [lib.basic.ios.cons], paragraph 3. Proposed resolution: [R12: modified to include paragraph 5.] In 27.3.1 [lib.narrow.stream.objects] paragraph 2 and 5, change
to
Also, make a similar change in 27.3.2 [lib.wide.stream.objects] except it should read
30. Wrong header for LC_*Section: 22.1.1.1.1 [lib.locale.category] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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>. Proposed resolution: In 22.1.1.1.1 [lib.locale.category], paragraph 2, change "<cctype>" to read "<clocale>". 31. Immutable locale valuesSection: 22.1.1 [lib.locale] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 Paragraph 6, says "An instance of locale is immutable; once a facet reference is obtained from it, ...". This has caused some confusion, because locale variables are manifestly assignable. Proposed resolution: In 22.1.1 [lib.locale] replace paragraph 6
with
32. Pbackfail description inconsistentSection: 27.5.2.4.4 [lib.streambuf.virt.pback] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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: traits::eq(c,gptr()[-1]) is false where pbackfail claims to require: traits::eq(*gptr(),traits::to_char_type(c)) returns false It appears that the pbackfail description is wrong. Proposed resolution: In 27.5.2.4.4 [lib.streambuf.virt.pback], paragraph 1, change:
to
Rationale: Note deliberate reordering of arguments for clarity in addition to the correction of the argument value. 33. Codecvt<> mentions from_typeSection: 22.2.1.5.2 [lib.locale.codecvt.virtuals] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 In the table defining the results from do_out and do_in, the specification for the result error says
but from_type is not defined. This clearly is intended to be an externT for do_in, or an internT for do_out. Proposed resolution: In 22.2.1.5.2 [lib.locale.codecvt.virtuals] paragraph 4, replace the definition in the table for the case of _error_ with
34. True/falsename() not in ctype<>Section: 22.2.2.2.2 [lib.facet.num.put.virtuals] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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). Proposed resolution: In 22.2.2.2.2 [lib.facet.num.put.virtuals], paragraph 19, in the Effects: clause for member put(...., bool), replace the initialization of the string_type value s as follows: const numpunct& np = use_facet<numpunct<charT> >(loc); string_type s = val ? np.truename() : np.falsename(); 35. No manipulator unitbuf in synopsisSection: 27.4 [lib.iostreams.base] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 In 27.4.5.1 [lib.fmtflags.manip], we have a definition for a manipulator named "unitbuf". Unlike other manipulators, it's not listed in synopsis. Similarly for "nounitbuf". Proposed resolution: Add to the synopsis for <ios> in 27.4 [lib.iostreams.base], after the entry for "nouppercase", the prototypes: ios_base& unitbuf(ios_base& str); ios_base& nounitbuf(ios_base& str); 36. Iword & pword storage lifetime omittedSection: 27.4.2.5 [lib.ios.base.storage] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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: The reference returned may become invalid after another call to the object's iword member with a different index ... This is not idle speculation; at least one implementation was done this way. Proposed resolution: Add in 27.4.2.5 [lib.ios.base.storage], in both paragraph 2 and also in paragraph 4, replace the sentence:
with:
substituting "iword" or "pword" as appropriate. 37. Leftover "global" referenceSection: 22.1.1 [lib.locale] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 In the overview of locale semantics, paragraph 4, is the sentence
This is not supported by the definition of use_facet<>, and represents semantics from an old draft. Proposed resolution: In 22.1.1 [lib.locale], paragraph 4, delete the parenthesized expression
38. Facet definition incompleteSection: 22.1.2 [lib.locale.global.templates] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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 id, cannot safely serve as the argument F to use_facet<F>(loc), because there is no guarantee that a reference to the facet instance stored in loc is safely convertible to F. Proposed resolution: In the definition of std::use_facet<>(), replace the text in paragraph 1 which reads:
with:
[ Kona: strike as overspecification the text "(not inherits)" from the original resolution, which read "... whose definition contains (not inherits) the public static member id..." ] 39. istreambuf_iterator<>::operator++(int) definition garbledSection: 24.5.3.4 [lib.istreambuf.iterator::op++] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. istreambuf_iterator<charT,traits> tmp = *this; sbuf_->sbumpc(); return(tmp); Proposed resolution: In 24.5.3.4 [lib.istreambuf.iterator::op++], delete the three lines of code at the end of paragraph 3. 40. Meaningless normative paragraph in examplesSection: 22.2.8 [lib.facets.examples] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 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. Proposed resolution: Delete 22.2.8 [lib.facets.examples] 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. 41. Ios_base needs clear(), exceptions()Section: 27.4.2 [lib.ios.base] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 The description of ios_base::iword() and pword() in 27.4.2.4 [lib.ios.members.static], 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<>. Proposed resolution: Change the description in 27.4.2.5 [lib.ios.base.storage] in paragraph 2, and also in paragraph 4, as follows. Replace
with
[Kona: LWG reviewed wording; setstate(failbit) changed to setstate(badbit).] 42. String ctors specify wrong default allocatorSection: 21.3 [lib.basic.string] Status: DR Submitter: Nathan Myers Date: 6 Aug 1998 The basic_string<> copy constructor: basic_string(const basic_string& str, size_type pos = 0, size_type n = npos, const Allocator& a = Allocator()); 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. 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. Proposed resolution: In 21.3 [lib.basic.string], replace the declaration of the copy constructor as follows: basic_string(const basic_string& str); basic_string(const basic_string& str, size_type pos, size_type n = npos, const Allocator& a = Allocator()); In 21.3.1 [lib.string.cons], replace the copy constructor declaration as above. Add to paragraph 5, Effects:
Rationale: The LWG believes the constructor is actually broken, rather than just an unfortunate design choice. The LWG considered two other possible resolutions: A. In 21.3 [lib.basic.string], replace the declaration of the copy constructor as follows: 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); In 21.3.1 [lib.string.cons], replace the copy constructor declaration as above. Add to paragraph 5, Effects:
B. In 21.3 [lib.basic.string], and also in 21.3.1 [lib.string.cons], replace the declaration of the copy constructor as follows: basic_string(const basic_string& str, size_type pos = 0, size_type n = npos); 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." [ Kona: issue editing snafu fixed - the proposed resolution now correctly reflects the LWG consensus. ] 46. Minor Annex D errorsSection: D.7 [depr.str.strstreams] Status: DR Submitter: Brendan Kehoe Date: 1 Jun 1998 See lib-6522 and edit-814. Proposed resolution: Change D.7.1 [depr.strstreambuf] (since streambuf is a typedef of basic_streambuf<char>) from: virtual streambuf<char>* setbuf(char* s, streamsize n); to: virtual streambuf* setbuf(char* s, streamsize n); In D.7.4 [depr.strstream] insert the semicolon now missing after int_type: 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; 47. Imbue() and getloc() Returns clauses swappedSection: 27.4.2.3 [lib.ios.base.locales] Status: DR Submitter: Matt Austern Date: 21 Jun 1998 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? Proposed resolution: In 27.4.2.3 [lib.ios.base.locales] swap paragraphs 2 and 4. 48. Use of non-existent exception constructorSection: 27.4.2.1.1 [lib.ios::failure] Status: DR Submitter: Matt Austern Date: 21 Jun 1998 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. Proposed resolution: Replace 27.4.2.1.1 [lib.ios::failure], paragraph 2, with
49. Underspecification of ios_base::sync_with_stdioSection: 27.4.2.4 [lib.ios.members.static] Status: DR Submitter: Matt Austern Date: 21 Jun 1998 Two problems (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. (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.) Proposed resolution: Change the following sentence in 27.4.2.4 [lib.ios.members.static] returns clause from:
to:
Add the following immediately after 27.4.2.4 [lib.ios.members.static], paragraph 2:
[pre-Copenhagen: PJP and Matt contributed the definition of "synchronization"] [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.] 50. Copy constructor and assignment operator of ios_baseSection: 27.4.2 [lib.ios.base] Status: DR Submitter: Matt Austern Date: 21 Jun 1998 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. 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. 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). Proposed resolution: In 27.4.2 [lib.ios.base], class ios_base, specify the copy constructor and operator= members as being private. Rationale: The LWG believes the difficulty of specifying correct semantics outweighs any benefit of allowing ios_base objects to be copyable. 51. Requirement to not invalidate iterators missingSection: 23.1 [lib.container.requirements] Status: DR Submitter: David Vandevoorde Date: 23 Jun 1998 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. Does the FDIS mandate anywhere which method should be used for list<>::sort()? Matt Austern comments: I think you've found an omission in the standard. 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. 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. 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. Proposed resolution: Add a new paragraph at the end of 23.1:
Rationale: 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" 52. Small I/O problemsSection: 27.4.3.2 [lib.fpos.operations] Status: DR Submitter: Matt Austern Date: 23 Jun 1998 First, 27.4.4.1 [lib.basic.ios.cons], table 89. This is pretty obvious: it should be titled "basic_ios<>() effects", not "ios_base() effects". [The second item is a duplicate; see issue 6 for resolution.] Second, 27.4.3.2 [lib.fpos.operations] 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. (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.) Proposed resolution: Change 27.4.4.1 [lib.basic.ios.cons] table 89 title from "ios_base() effects" to "basic_ios<>() effects". 53. Basic_ios destructor unspecifiedSection: 27.4.4.1 [lib.basic.ios.cons] Status: DR Submitter: Matt Austern Date: 23 Jun 1998 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(). Proposed resolution: Add after 27.4.4.1 [lib.basic.ios.cons] paragraph 2:
Rationale: The LWG reviewed the additional question of whether or not rdbuf(0) may set badbit. The answer is clearly yes; it may be set via clear(). See 27.4.4.2 [lib.basic.ios.members], paragraph 6. This issue was reviewed at length by the LWG, which removed from the original proposed resolution a footnote which incorrectly said "rdbuf(0) does not set badbit". 54. Basic_streambuf's destructorSection: 27.5.2.1 [lib.streambuf.cons] Status: DR Submitter: Matt Austern Date: 25 Jun 1998 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. Proposed resolution: Add after 27.5.2.1 [lib.streambuf.cons] paragraph 2:
55. Invalid stream position is undefinedSection: 27 [lib.input.output] Status: DR Submitter: Matt Austern Date: 26 Jun 1998 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. 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. 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:
Proposed resolution: In 27.5.2.4.2 [lib.streambuf.virt.buffer], paragraph 4, change "Returns an object of class pos_type that stores an invalid stream position (_lib.iostreams.definitions_)" to "Returns pos_type(off_type(-1))". In 27.5.2.4.2 [lib.streambuf.virt.buffer], paragraph 6, change "Returns an object of class pos_type that stores an invalid stream position" to "Returns pos_type(off_type(-1))". In 27.7.1.3 [lib.stringbuf.virtuals], paragraph 13, change "the object stores an invalid stream position" to "the return value is pos_type(off_type(-1))". In 27.8.1.4 [lib.filebuf.virtuals], paragraph 13, change "returns an invalid stream position (27.4.3)" to "returns pos_type(off_type(-1))" In 27.8.1.4 [lib.filebuf.virtuals], paragraph 15, change "Otherwise returns an invalid stream position (_lib.iostreams.definitions_)" to "Otherwise returns pos_type(off_type(-1))" In D.7.1.3 [depr.strstreambuf.virtuals], paragraph 15, change "the object stores an invalid stream position" to "the return value is pos_type(off_type(-1))" In D.7.1.3 [depr.strstreambuf.virtuals], paragraph 18, change "the object stores an invalid stream position" to "the return value is pos_type(off_type(-1))" 56. Showmanyc's return typeSection: 27.5.2 [lib.streambuf] Status: DR Submitter: Matt Austern Date: 29 Jun 1998 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. Proposed resolution: Change showmanyc's return type in the 27.5.2 [lib.streambuf] class summary to streamsize. 57. Mistake in char_traitsSection: 21.1.3.2 [lib.char.traits.specializations.wchar.t] Status: DR Submitter: Matt Austern Date: 1 Jul 1998 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". 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. Proposed resolution: Remove the sentence in 21.1.3.2 [lib.char.traits.specializations.wchar.t] paragraph 3 which begins "The types streampos and wstreampos may be different..." . 59. Ambiguity in specification of gbumpSection: 27.5.2.3.1 [lib.streambuf.get.area] Status: DR Submitter: Matt Austern Date: 28 Jul 1998 27.5.2.3.1 says that basic_streambuf::gbump() "Advances the next pointer for the input sequence by n." 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. (The "classic" AT&T implementation used the former interpretation.) Proposed resolution: Change 27.5.2.3.1 [lib.streambuf.get.area] paragraph 4 gbump effects from:
to:
Make the same change to 27.5.2.3.2 [lib.streambuf.put.area] paragraph 4 pbump effects. 60. What is a formatted input function?Section: 27.6.1.2.1 [lib.istream.formatted.reqmts] Status: DR Submitter: Matt Austern Date: 3 Aug 1998 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 basic_istream& operator>>(basic_istream& (*pf)(basic_istream&)); and basic_istream& operator>>(basic_streammbuf*); There is a similar ambiguity for unformatted input, formatted output, and unformatted output. 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. Additional comments from Dietmar Kühl: It appears to be somewhat nonsensical to consider the functions defined in 27.6.1.2.3 [lib.istream::extractors] 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 [lib.istream.formatted.reqmts]: If this is the case, all manipulators, not just ws, would skip whitespace unless noskipws is set (... but setting noskipws using the manipulator syntax would also skip whitespace :-) 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 [lib.istream.unformatted] are unformatted input functions. However, it does not really make much sense to construct a sentry object for gcount(), sync(), ... Also it is unclear what happens to the gcount() if eg. gcount(), putback(), unget(), or sync() is called: These functions don't extract characters, some of them even "unextract" a character. Should this still be reflected in gcount()? Of course, it could be read as if after a call to gcount() gcount() return 0 (the last unformatted input function, gcount(), didn't extract any character) and after a call to putback() gcount() returns -1 (the last unformatted input function putback() did "extract" back into the stream). Correspondingly for unget(). Is this what is intended? If so, this should be clarified. Otherwise, a corresponding clarification should be used. Proposed resolution: 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" 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). 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). 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). 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...". 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)." 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" 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" 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" [No change needed in paragraph 10, because it refers to paragraph 7.] 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" [No change needed in paragraph 15.] 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" [No change needed in paragraph 23.] 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" 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." 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" 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" 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.]" 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.]" 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" 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()". 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() 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() 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". 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).". 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).". 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).". 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". 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". 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". 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)." Rationale: 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. 61. Ambiguity in iostreams exception policySection: 27.6.1.3 [lib.istream.unformatted] Status: DR Submitter: Matt Austern Date: 6 Aug 1998 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. char buffer[N]; istream is; ... is.exceptions(istream::failbit); // Throw on failbit but not on badbit. is.read(buffer, N); 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? Proposed resolution: 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 basic_ios<>::clear() are not caught or rethrown.)" Rationale: The LWG looked to two alternative wordings, and choose the proposed resolution as better standardese. 62. Sync's return valueSection: 27.6.1.3 [lib.istream.unformatted] Status: DR Submitter: Matt Austern Date: 6 Aug 1998 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()." That looks suspicious, because traits::eof() is of type traits::int_type while the return type of sync() is int. Proposed resolution: In 27.6.1.3 [lib.istream.unformatted], paragraph 36, change "returns traits::eof()" to "returns -1". 63. Exception-handling policy for unformatted outputSection: 27.6.2.6 [lib.ostream.unformatted] Status: DR Submitter: Matt Austern Date: 11 Aug 1998 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. Proposed resolution: 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: If an exception is thrown during output, then ios::badbit is turned on [Footnote: without causing an ios::failure to be thrown.] in *this's error state. If (exceptions() & badbit) != 0 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. Rationale: This exception-handling policy is consistent with that of formatted input, unformatted input, and formatted output. 64. Exception handling in basic_istream::operator>>(basic_streambuf*)Section: 27.6.1.2.3 [lib.istream::extractors] Status: DR Submitter: Matt Austern Date: 11 Aug 1998 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. Proposed resolution: Replace 27.6.1.2.3 [lib.istream::extractors], paragraph 13, which begins "If the function inserts no characters ..." with:
66. Strstreambuf::setbufSection: D.7.1.3 [depr.strstreambuf.virtuals] Status: DR Submitter: Matt Austern Date: 18 Aug 1998 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. Proposed resolution: D.7.1.3 [depr.strstreambuf.virtuals], paragraph 19, replace the setbuf effects clause which currently says "Performs an operation that is defined separately for each class derived from strstreambuf" with:
68. Extractors for char* should store null at endSection: 27.6.1.2.3 [lib.istream::extractors] Status: DR Submitter: Angelika Langer Date: 14 Jul 1998 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? 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. Proposed resolution: 27.6.1.2.3 [lib.istream::extractors], paragraph 7, change the last list item from: A null byte (charT()) in the next position, which may be the first position if no characters were extracted. to become a new paragraph which reads: Operator>> then stores a null byte (charT()) in the next position, which may be the first position if no characters were extracted. 69. Must elements of a vector be contiguous?Section: 23.2.4 [lib.vector] Status: DR Submitter: Andrew Koenig Date: 29 Jul 1998 The issue is this: Must the elements of a vector be in contiguous memory? (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) Proposed resolution: Add the following text to the end of 23.2.4 [lib.vector], paragraph 1.
Rationale: 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:
70. Uncaught_exception() missing throw() specificationSection: 18.6 [lib.support.exception], 18.6.4 [lib.uncaught] Status: DR Submitter: Steve Clamage Date: Unknown In article 3E04@pratique.fr, Valentin Bonnard writes: uncaught_exception() doesn't have a throw specification. It is intentional ? Does it means that one should be prepared to handle exceptions thrown from uncaught_exception() ? uncaught_exception() is called in exception handling contexts where exception safety is very important. Proposed resolution: In 15.5.3 [except.uncaught], paragraph 1, 18.6 [lib.support.exception], and 18.6.4 [lib.uncaught], add "throw()" to uncaught_exception(). 71. Do_get_monthname synopsis missing argumentSection: 22.2.5.1 [lib.locale.time.get] Status: DR Submitter: Nathan Myers Date: 13 Aug 1998 The locale facet member time_get<>::do_get_monthname is described in 22.2.5.1.2 [lib.locale.time.get.virtuals] 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. Proposed resolution: In 22.2.5.1 [lib.locale.time.get], add an "end" argument to the declaration of member do_monthname as follows: virtual iter_type do_get_monthname(iter_type s, iter_type end, ios_base&, ios_base::iostate& err, tm* t) const; 74. Garbled text for codecvt::do_max_lengthSection: 22.2.1.5.2 [lib.locale.codecvt.virtuals] Status: DR Submitter: Matt Austern Date: 8 Sep 1998 The text of codecvt::do_max_length's "Returns" clause (22.2.1.5.2, paragraph 11) is garbled. It has unbalanced parentheses and a spurious n. Proposed resolution: Replace 22.2.1.5.2 [lib.locale.codecvt.virtuals] paragraph 11 with the following: Returns: The maximum value that do_length(state, from, from_end, 1) can return for any valid range [from, from_end) and stateT value state. The specialization codecvt<char, char, mbstate_t>::do_max_length() returns 1. 75. Contradiction in codecvt::length's argument typesSection: 22.2.1.5 [lib.locale.codecvt] Status: DR Submitter: Matt Austern Date: 18 Sep 1998 The class synopses for classes codecvt<> (22.2.1.5) and codecvt_byname<> (22.2.1.6) say that the first parameter of the member functions length and do_length is of type const stateT&. The member function descriptions, however (22.2.1.5.1, paragraph 6; 22.2.1.5.2, paragraph 9) say that the type is stateT&. Either the synopsis or the summary must be changed. If (as I believe) the member function descriptions are correct, then we must also add text saying how do_length changes its stateT argument. Proposed resolution: In 22.2.1.5 [lib.locale.codecvt], and also in 22.2.1.6 [lib.locale.codecvt.byname], change the stateT argument type on both member length() and member do_length() from
to
In 22.2.1.5.2 [lib.locale.codecvt.virtuals], add to the definition for member do_length a paragraph:
78. Typo: event_call_backSection: 27.4.2 [lib.ios.base] Status: DR Submitter: Nico Josuttis Date: 29 Sep 1998 typo: event_call_back should be event_callback Proposed resolution: In the 27.4.2 [lib.ios.base] synopsis change "event_call_back" to "event_callback". 79. Inconsistent declaration of polar()Section: 26.2.1 [lib.complex.synopsis], 26.2.7 [lib.complex.value.ops] Status: DR Submitter: Nico Josuttis Date: 29 Sep 1998 In 26.2.1 [lib.complex.synopsis] polar is declared as follows: template<class T> complex<T> polar(const T&, const T&); In 26.2.7 [lib.complex.value.ops] it is declared as follows: template<class T> complex<T> polar(const T& rho, const T& theta = 0); Thus whether the second parameter is optional is not clear. Proposed resolution: In 26.2.1 [lib.complex.synopsis] change: template<class T> complex<T> polar(const T&, const T&); to: template<class T> complex<T> polar(const T& rho, const T& theta = 0); 80. Global Operators of complex declared twiceSection: 26.2.1 [lib.complex.synopsis], 26.2.2 [lib.complex] Status: DR Submitter: Nico Josuttis Date: 29 Sep 1998 Both 26.2.1 and 26.2.2 contain declarations of global operators for class complex. This redundancy should be removed. Proposed resolution: Reduce redundancy according to the general style of the standard. 83. String::npos vs. string::max_size()Section: 21.3 [lib.basic.string] Status: DR Submitter: Nico Josuttis Date: 29 Sep 1998 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. Proposed resolution: After 21.3 [lib.basic.string] paragraph 4 ("The functions described in this clause...") add a new paragraph:
Rationale: The LWG believes length_error is the correct exception to throw. 86. String constructors don't describe exceptionsSection: 21.3.1 [lib.string.cons] Status: DR Submitter: Nico Josuttis Date: 29 Sep 1998 The constructor from a range: template<class InputIterator> basic_string(InputIterator begin, InputIterator end, const Allocator& a = Allocator()); 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). Proposed resolution: In 21.3.1 [lib.string.cons], Strike throws paragraphs for constructors which say "Throws: length_error if n == npos." Rationale: 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 83. 90. Incorrect description of operator >> for stringsSection: 21.3.7.9 [lib.string.io] Status: DR Submitter: Nico Josuttis Date: 29 Sep 1998 The effect of operator >> for strings contain the following item: isspace(c,getloc()) is true for the next available input character c. Here getloc() has to be replaced by is.getloc(). Proposed resolution: In 21.3.7.9 [lib.string.io] paragraph 1 Effects clause replace:
with:
103. set::iterator is required to be modifiable, but this allows modification of keysSection: 23.1.2 [lib.associative.reqmts] Status: DR Submitter: AFNOR Date: 7 Oct 1998 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. 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: typedef implementation defined iterator; 23.1 [lib.container.requirements] 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. Other Options Evaluated: Option A. In 23.1.2 [lib.associative.reqmts], paragraph 2, after first sentence, and before "In addition,...", add one line:
Option B. Add three new sentences to 23.1.2 [lib.associative.reqmts]:
Option C. To 23.1.2 [lib.associative.reqmts], paragraph 3, which currently reads:
add the following:
Proposed resolution: Add the following to 23.1.2 [lib.associative.reqmts] at the indicated location:
Rationale: 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. Simply requiring that keys be immutable is not sufficient, because the comparison object may indirectly (via pointers) operate on values outside of the keys. The types iterator and const_iterator 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 const_iterator alone, and can rely on the automatic conversion from iterator to const_iterator. [Tokyo: The LWG crafted the proposed resolution and rationale.] 106. Numeric library private members are implementation definedSection: 26.3.5 [lib.template.slice.array] Status: DR Submitter: AFNOR Date: 7 Oct 1998 This is the only place in the whole standard where the implementation has to document something private. Proposed resolution: Remove the comment which says "// remainder implementation defined" from:
108. Lifetime of exception::what() return unspecifiedSection: 18.6.1 [lib.exception] Status: DR Submitter: AFNOR Date: 7 Oct 1998 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. Proposed resolution: Add to 18.6.1 [lib.exception] paragraph 9 (exception::what notes clause) the sentence:
Rationale: 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 what(). 109. Missing binders for non-const sequence elementsSection: 20.3.6 [lib.binders] Status: DR Submitter: Bjarne Stroustrup Date: 7 Oct 1998 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. Further discussion from Nico: What is probably meant here is shown in the following example: class Elem { public: void print (int i) const { } void modify (int i) { } }; 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 } 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: 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) {}typename Operation::result_type operator()(const typename Operation::first_argument_type& x) const { return op(x, value); } }; The solution is to overload operator () of bind2nd for non-constant arguments: 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) {}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); } }; Proposed resolution: Howard believes there is a flaw in this resolution. See c++std-lib-9127. We may need to reopen this issue. In 20.3.6.1 [lib.binder.1st] in the declaration of binder1st after:
insert:
In 20.3.6.3 [lib.binder.2nd] in the declaration of binder2nd after:
insert:
[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.] [Copenhagen: It was generally agreed that this was a defect. Strap poll: NAD - 0. Accept proposed resolution - 10. Leave open - 1.] 110. istreambuf_iterator::equal not constSection: 24.5.3 [lib.istreambuf.iterator], 24.5.3.5 [lib.istreambuf.iterator::equal] Status: DR Submitter: Nathan Myers Date: 15 Oct 1998 Member istreambuf_iterator<>::equal is not declared "const", yet 24.5.3.6 [lib.istreambuf.iterator::op==] says that operator==, which is const, calls it. This is contradictory. Proposed resolution: In 24.5.3 [lib.istreambuf.iterator] and also in 24.5.3.5 [lib.istreambuf.iterator::equal], replace: bool equal(istreambuf_iterator& b); with: bool equal(const istreambuf_iterator& b) const; 112. Minor typo in ostreambuf_iterator constructorSection: 24.5.4.1 [lib.ostreambuf.iter.cons] Status: DR Submitter: Matt Austern Date: 20 Oct 1998 The requires clause for ostreambuf_iterator's constructor from an ostream_type (24.5.4.1, paragraph 1) reads "s is not null". However, s is a reference, and references can't be null. Proposed resolution: In 24.5.4.1 [lib.ostreambuf.iter.cons]: Move the current paragraph 1, which reads "Requires: s is not null.", from the first constructor to the second constructor. Insert a new paragraph 1 Requires clause for the first constructor reading:
114. Placement forms example in error twiceSection: 18.4.1.3 [lib.new.delete.placement] Status: DR Submitter: Steve Clamage Date: 28 Oct 1998 Section 18.4.1.3 contains the following example: [Example: This can be useful for constructing an object at a known address: char place[sizeof(Something)]; Something* p = new (place) Something(); -end example] First code line: "place" need not have any special alignment, and the following constructor could fail due to misaligned data. Second code line: Aren't the parens on Something() incorrect? [Dublin: the LWG believes the () are correct.] Examples are not normative, but nevertheless should not show code that is invalid or likely to fail. Proposed resolution: Replace the first line of code in the example in 18.4.1.3 [lib.new.delete.placement] with: void* place = operator new(sizeof(Something)); 115. Typo in strstream constructorsSection: D.7.4.1 [depr.strstream.cons] Status: DR Submitter: Steve Clamage Date: 2 Nov 1998 D.7.4.1 strstream constructors paragraph 2 says:
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. Proposed resolution: In D.7.3.1 [depr.ostrstream.cons] paragraph 2 and D.7.4.1 [depr.strstream.cons] paragraph 2, change the first condition to (mode&app)==0 and the second condition to (mode&app)!=0. 117. basic_ostream uses nonexistent num_put member functionsSection: 27.6.2.5.2 [lib.ostream.inserters.arithmetic] Status: DR Submitter: Matt Austern Date: 20 Nov 1998 The effects clause for numeric inserters says that insertion of a value x, whose type is either bool, short, unsigned short, int, unsigned int, long, unsigned long, float, double, long double, or const void*, is delegated to num_put, and that insertion is performed as if through the following code fragment: bool failed = use_facet< num_put<charT,ostreambuf_iterator<charT,traits> > >(getloc()).put(*this, *this, fill(), val). failed(); This doesn't work, because num_put<>::put is only overloaded for the types bool, long, unsigned long, double, long double, and const void*. That is, the code fragment in the standard is incorrect (it is diagnosed as ambiguous at compile time) for the types short, unsigned short, int, unsigned int, and float. We must either add new member functions to num_put, or else change the description in ostream so that it only calls functions that are actually there. I prefer the latter. Proposed resolution: Replace 27.6.2.5.2, paragraph 1 with the following:
[post-Toronto: This differs from the previous proposed resolution; PJP provided the new wording. The differences are in signed short and int output.] Rationale: 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.) 118. basic_istream uses nonexistent num_get member functionsSection: 27.6.1.2.2 [lib.istream.formatted.arithmetic] Status: DR Submitter: Matt Austern Date: 20 Nov 1998 Formatted input is defined for the types short, unsigned short, int, unsigned int, long, unsigned long, float, double, long double, bool, and void*. According to section 27.6.1.2.2, formatted input of a value x is done as if by the following code fragment: typedef num_get< charT,istreambuf_iterator<charT,traits> > numget; iostate err = 0; use_facet< numget >(loc).get(*this, 0, *this, err, val); setstate(err); According to section 22.2.2.1.1 [lib.facet.num.get.members], however, num_get<>::get() is only overloaded for the types bool, long, unsigned short, unsigned int, unsigned long, unsigned long, float, double, long double, and void*. Comparing the lists from the two sections, we find that 27.6.1.2.2 is using a nonexistent function for types short and int. Proposed resolution: In 27.6.1.2.2 [lib.istream.formatted.arithmetic] Arithmetic Extractors, remove the two lines (1st and 3rd) which read: operator>>(short& val); ... operator>>(int& val); And add the following at the end of that section (27.6.1.2.2) : operator>>(short& val); [Post-Tokyo: PJP provided the above wording.] 119. Should virtual functions be allowed to strengthen the exception specification?Section: 17.4.4.8 [lib.res.on.exception.handling] Status: DR Submitter: Judy Ward Date: 15 Dec 1998 Section 17.4.4.8 [lib.res.on.exception.handling] states: "An implementation may strengthen the exception-specification for a function by removing listed exceptions." 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. For example, this would not compile if ios_base::failure::~failure had an empty exception specification: #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() }; Proposed resolution: Change Section 17.4.4.8 [lib.res.on.exception.handling] from: "may strengthen the exception-specification for a function" to: "may strengthen the exception-specification for a non-virtual function". 122. streambuf/wstreambuf description should not say they are specializationsSection: 27.5.2 [lib.streambuf] Status: DR Submitter: Judy Ward Date: 15 Dec 1998 Section 27.5.2 describes the streambuf classes this way:
This implies that these classes must be template specializations, not typedefs. It doesn't seem this was intended, since Section 27.5 has them declared as typedefs. Proposed resolution: Remove 27.5.2 [lib.streambuf] paragraphs 2 and 3 (the above two sentences). Rationale: The streambuf synopsis already has a declaration for the typedefs and that is sufficient. 124. ctype_byname<charT>::do_scan_is & do_scan_not return type should be const charT*Section: 22.2.1.2 [lib.locale.ctype.byname] Status: DR Submitter: Judy Ward Date: 15 Dec 1998 In Section 22.2.1.2 [lib.locale.ctype.byname] ctype_byname<charT>::do_scan_is() and do_scan_not() are declared to return a const char* not a const charT*. Proposed resolution: Change Section 22.2.1.2 [lib.locale.ctype.byname] do_scan_is() and do_scan_not() to return a const charT*. 125. valarray<T>::operator!() return type is inconsistentSection: 26.3.2 [lib.template.valarray] Status: DR Submitter: Judy Ward Date: 15 Dec 1998 In Section 26.3.2 [lib.template.valarray] valarray<T>::operator!() is declared to return a valarray<T>, but in Section 26.3.2.5 [lib.valarray.unary] it is declared to return a valarray<bool>. The latter appears to be correct. Proposed resolution: Change in Section 26.3.2 [lib.template.valarray] the declaration of operator!() so that the return type is valarray<bool>. 126. typos in Effects clause of ctype::do_narrow()Section: 22.2.1.1.2 [lib.locale.ctype.virtuals] Status: DR Submitter: Judy Ward Date: 15 Dec 1998 Typos in 22.2.1.1.2 need to be fixed. Proposed resolution: In Section 22.2.1.1.2 [lib.locale.ctype.virtuals] change: do_widen(do_narrow(c),0) == c to: do_widen(do_narrow(c,0)) == c and change: (is(M,c) || !ctc.is(M, do_narrow(c),dfault) ) to: (is(M,c) || !ctc.is(M, do_narrow(c,dfault)) ) 127. auto_ptr<> conversion issuesSection: 20.4.5 [lib.auto.ptr] Status: DR Submitter: Greg Colvin Date: 17 Feb 1999 There are two problems with the current auto_ptr wording in the standard: First, the auto_ptr_ref definition cannot be nested because auto_ptr<Derived>::auto_ptr_ref is unrelated to auto_ptr<Base>::auto_ptr_ref. Also submitted by Nathan Myers, with the same proposed resolution. Second, there is no auto_ptr assignment operator taking an auto_ptr_ref argument. 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. 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. 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]. Tokyo: The LWG removed the following from the proposed resolution: In 20.4.5 [lib.auto.ptr], paragraph 2, and 20.4.5.3 [lib.auto.ptr.conv], paragraph 2, make the conversion to auto_ptr_ref const: template<class Y> operator auto_ptr_ref<Y>() const throw(); Proposed resolution: In 20.4.5 [lib.auto.ptr], paragraph 2, move the auto_ptr_ref definition to namespace scope. In 20.4.5 [lib.auto.ptr], paragraph 2, add a public assignment operator to the auto_ptr definition: auto_ptr& operator=(auto_ptr_ref<X> r) throw(); Also add the assignment operator to 20.4.5.3 [lib.auto.ptr.conv]: auto_ptr& operator=(auto_ptr_ref<X> r) throw()Effects: Calls reset(p.release()) for the auto_ptr p that r holds a reference to. 129. Need error indication from seekp() and seekg()Section: 27.6.1.3 [lib.istream.unformatted], 27.6.2.4 [lib.ostream.seeks] Status: DR Submitter: Angelika Langer Date: 22 Feb 1999 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 can 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. The stream functions seekg() and seekp() should set failbit in the stream state in case of failure. Proposed resolution: Add to the Effects: clause of seekg() in 27.6.1.3 [lib.istream.unformatted] and to the Effects: clause of seekp() in 27.6.2.4 [lib.ostream.seeks]:
Rationale: Setting failbit is the usual error reporting mechanism for streams 132. list::resize description uses random access iteratorsSection: 23.2.2.2 [lib.list.capacity] Status: DR Submitter: Howard Hinnant Date: 6 Mar 1999 The description reads: -1- Effects: if (sz > size()) insert(end(), sz-size(), c); else if (sz < size()) erase(begin()+sz, end()); else ; // do nothing Obviously list::resize should not be specified in terms of random access iterators. Proposed resolution: Change 23.2.2.2 paragraph 1 to: Effects: if (sz > size()) insert(end(), sz-size(), c); else if (sz < size()) { iterator i = begin(); advance(i, sz); erase(i, end()); } [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.] 133. map missing get_allocator()Section: 23.3.1 [lib.map] Status: DR Submitter: Howard Hinnant Date: 6 Mar 1999 The title says it all. Proposed resolution: Insert in 23.3.1 [lib.map], paragraph 2, after operator= in the map declaration: allocator_type get_allocator() const; 134. vector constructors over specifiedSection: 23.2.4.1 [lib.vector.cons] Status: DR Submitter: Howard Hinnant Date: 6 Mar 1999 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 ...". This appears to be overly restrictive, dictating the precise memory/performance tradeoff for the implementor. Proposed resolution: Change 23.2.4.1 [lib.vector.cons], paragraph 1 to: -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. Rationale: "at most 2N calls" is correct only if the growth factor is greater than or equal to 2. 136. seekp, seekg setting wrong streams?Section: 27.6.1.3 [lib.istream.unformatted] Status: DR Submitter: Howard Hinnant Date: 6 Mar 1999 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. Proposed resolution: In section 27.6.1.3 change: basic_istream<charT,traits>& seekg(pos_type pos); Effects: If fail() != true, executes rdbuf()->pubseekpos(pos). To: basic_istream<charT,traits>& seekg(pos_type pos); Effects: If fail() != true, executes rdbuf()->pubseekpos(pos, ios_base::in). In section 27.6.1.3 change: basic_istream<charT,traits>& seekg(off_type& off, ios_base::seekdir dir); Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir). To: basic_istream<charT,traits>& seekg(off_type& off, ios_base::seekdir dir); Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir, ios_base::in). In section 27.6.2.4, paragraph 2 change: -2- Effects: If fail() != true, executes rdbuf()->pubseekpos(pos). To: -2- Effects: If fail() != true, executes rdbuf()->pubseekpos(pos, ios_base::out). In section 27.6.2.4, paragraph 4 change: -4- Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir). To: -4- Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir, ios_base::out). [Dublin: Dietmar Kühl thinks this is probably correct, but would like the opinion of more iostream experts before taking action.] [Tokyo: Reviewed by the LWG. PJP noted that although his docs are incorrect, his implementation already implements the Proposed Resolution.] [Post-Tokyo: Matt Austern comments: 137. Do use_facet and has_facet look in the global locale?Section: 22.1.1 [lib.locale] Status: DR Submitter: Angelika Langer Date: 17 Mar 1999 Section 22.1.1 [lib.locale] says: -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>(). This contradicts the specification given in section
22.1.2 [lib.locale.global.templates]:
Proposed resolution: Remove the phrase "(or, failing that, in the global locale)" from section 22.1.1. Rationale: Needed for consistency with the way locales are handled elsewhere in the standard. 139. Optional sequence operation table description unclearSection: 23.1.1 [lib.sequence.reqmts] Status: DR Submitter: Andrew Koenig Date: 30 Mar 1999 The sentence introducing the Optional sequence operation table (23.1.1 paragraph 12) has two problems: A. It says ``The operations in table 68 are provided only for the containers for which
they take constant time.'' Proposed resolution: Replace the wording in 23.1.1 paragraph 12 which begins ``The operations in table 68 are provided only..." with:
141. basic_string::find_last_of, find_last_not_of say pos instead of xposSection: 21.3.6.4 [lib.string::find.last.of], 21.3.6.6 [lib.string::find.last.not.of] Status: DR Submitter: Arch Robison Date: 28 Apr 1999 Sections 21.3.6.4 paragraph 1 and 21.3.6.6 paragraph 1 surely have misprints where they
say: Surely the document meant to say ``xpos < size()'' in both places. [Judy Ward also sent in this issue for 21.3.6.4 with the same proposed resolution.] Proposed resolution: Change Sections 21.3.6.4 paragraph 1 and 21.3.6.6 paragraph 1, the line which says: 142. lexicographical_compare complexity wrongSection: 25.3.8 [lib.alg.lex.comparison] Status: DR Submitter: Howard Hinnant Date: 20 Jun 1999 The lexicographical_compare complexity is specified as: 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) Proposed resolution: Change 25.3.8 [lib.alg.lex.comparison] complexity to: At most 2*min((last1 - first1), (last2 - first2)) applications of the corresponding comparison. Change the example at the end of paragraph 3 to read: [Example: 144. Deque constructor complexity wrongSection: 23.2.1.1 [lib.deque.cons] Status: DR Submitter: Herb Sutter Date: 9 May 1999 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:
The word "reallocations" does not really apply to deque. Further, all of the following appears to be spurious:
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? Proposed resolution: In 23.2.1.1 paragraph 6, replace the Complexity description, including the footnote, with the following text (which also corrects the "abd" typo):
146. complex<T> Inserter and Extractor need sentriesSection: 26.2.6 [lib.complex.ops] Status: DR Submitter: Angelika Langer Date: 12 May 1999 The extractor for complex numbers is specified as:
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?
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. 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. Proposed resolution: After 26.2.6 [lib.complex.ops] paragraph 14 (operator>>), add a Notes clause:
Rationale: For extractors, the note is added to make it clear that skipping whitespace follows an "all-or-none" rule. For inserters, the LWG believes there is no defect; the standard is correct as written. 147. Library Intro refers to global functions that aren't globalSection: 17.4.4.3 [lib.global.functions] Status: DR Submitter: Lois Goldthwaite Date: 4 Jun 1999 The library had many global functions until 17.4.1.1 [lib.contents] paragraph 2 was added:
It appears "global function" was never updated in the following:
Proposed resolution: Change "global" to "global or non-member" in:
Rationale: Because operator new and delete are global, the proposed resolution was changed from "non-member" to "global or non-member. 148. Functions in the example facet BoolNames should be constSection: 22.2.8 [lib.facets.examples] Status: DR Submitter: Jeremy Siek Date: 3 Jun 1999 In 22.2.8 [lib.facets.examples] 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. Proposed resolution: In 22.2.8 [lib.facets.examples] paragraph 13, insert "const" in two places:
150. Find_first_of says integer instead of iteratorSection: 25.1.4 [lib.alg.find.first.of] Status: DR Submitter: Matt McClure Date: 30 Jun 1999 Proposed resolution: Change 25.1.4 [lib.alg.find.first.of] paragraph 2 from:
to:
151. Can't currently clear() empty containerSection: 23.1.1 [lib.sequence.reqmts] Status: DR Submitter: Ed Brey Date: 21 Jun 1999 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. Proposed resolution: In 23.1.1, paragraph 3, change:
to:
In 23.1.2, paragraph 7, change:
to
152. Typo in scan_is() semanticsSection: 22.2.1.1.2 [lib.locale.ctype.virtuals] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The semantics of scan_is() (paragraphs 4 and 6) is not exactly described because there is no function is() which only takes a character as argument. Also, in the effects clause (paragraph 3), the semantic is also kept vague. Proposed resolution: In 22.2.1.1.2 [lib.locale.ctype.virtuals] paragraphs 4 and 6, change the returns clause from:
to: "... such that is(m, *p) would...." 153. Typo in narrow() semanticsSection: 22.2.1.3.2 [lib.facet.ctype.char.members] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The description of the array version of narrow() (in paragraph 11) is flawed: There is no member do_narrow() which takes only three arguments because in addition to the range a default character is needed. Additionally, for both widen and narrow we have two signatures followed by a Returns clause that only addresses one of them. Proposed resolution: Change the returns clause in 22.2.1.3.2 [lib.facet.ctype.char.members] paragraph 10 from: Returns: do_widen(low, high, to). to: Returns: do_widen(c) or do_widen(low, high, to), respectively. Change 22.2.1.3.2 [lib.facet.ctype.char.members] paragraph 10 and 11 from: char narrow(char c, char /*dfault*/) const; const char* narrow(const char* low, const char* high, char /*dfault*/, char* to) const; Returns: do_narrow(low, high, to). to: char narrow(char c, char dfault) const; const char* narrow(const char* low, const char* high, char dfault, char* to) const; Returns: do_narrow(c, dfault) or do_narrow(low, high, dfault, to), respectively. [Kona: 1) the problem occurs in additional places, 2) a user defined version could be different.] [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?] [Post-Toronto: the issues list maintainer has merged in the proposed resolution from issue 207, which addresses the same paragraphs.] 154. Missing double specifier for do_get()Section: 22.2.2.1.2 [lib.facet.num.get.virtuals] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The table in paragraph 7 for the length modifier does not list the length modifier l to be applied if the type is double. Thus, the standard asks the implementation to do undefined things when using scanf() (the missing length modifier for scanf() when scanning doubles is actually a problem I found quite often in production code, too). Proposed resolution: In 22.2.2.1.2 [lib.facet.num.get.virtuals], paragraph 7, add a row in the Length Modifier table to say that for double a length modifier l is to be used. Rationale: The standard makes an embarrassing beginner's mistake. 155. Typo in naming the class defining the class InitSection: 27.3 [lib.iostream.objects] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 There are conflicting statements about where the class Init is defined. According to 27.3 [lib.iostream.objects] paragraph 2 it is defined as basic_ios::Init, according to 27.4.2 [lib.ios.base] it is defined as ios_base::Init. Proposed resolution: Change 27.3 [lib.iostream.objects] paragraph 2 from "basic_ios::Init" to "ios_base::Init". Rationale: Although not strictly wrong, the standard was misleading enough to warrant the change. 156. Typo in imbue() descriptionSection: 27.4.2.3 [lib.ios.base.locales] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 There is a small discrepancy between the declarations of imbue(): in 27.4.2 [lib.ios.base] the argument is passed as locale const& (correct), in 27.4.2.3 [lib.ios.base.locales] it is passed as locale const (wrong). Proposed resolution: In 27.4.2.3 [lib.ios.base.locales] change the imbue argument from "locale const" to "locale const&". 158. Underspecified semantics for setbuf()Section: 27.5.2.4.2 [lib.streambuf.virt.buffer] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The default behavior of setbuf() is described only for the situation that gptr() != 0 && gptr() != egptr(): 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. 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 setbuf() should always be to do nothing. Proposed resolution: Change 27.5.2.4.2 [lib.streambuf.virt.buffer], paragraph 3, Default behavior, to: "Default behavior: Does nothing. Returns this." 159. Strange use of underflow()Section: 27.5.2.4.3 [lib.streambuf.virt.get] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The description of the meaning of the result of showmanyc() seems to be rather strange: It uses calls to underflow(). Using underflow() is strange because this function only reads the current character but does not extract it, uflow() would extract the current character. This should be fixed to use sbumpc() instead. Proposed resolution: Change 27.5.2.4.3 [lib.streambuf.virt.get] paragraph 1, showmanyc()returns clause, by replacing the word "supplied" with the words "extracted from the stream". 160. Typo: Use of non-existing function exception()Section: 27.6.1.1 [lib.istream] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The paragraph 4 refers to the function exception() which is not defined. Probably, the referred function is basic_ios<>::exceptions(). Proposed resolution: In 27.6.1.1 [lib.istream], 27.6.1.3 [lib.istream.unformatted], paragraph 1, 27.6.2.1 [lib.ostream], paragraph 3, and 27.6.2.5.1 [lib.ostream.formatted.reqmts], paragraph 1, change "exception()" to "exceptions()". [Note to Editor: "exceptions" with an "s" is the correct spelling.] 161. Typo: istream_iterator vs. istreambuf_iteratorSection: 27.6.1.2.2 [lib.istream.formatted.arithmetic] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The note in the second paragraph pretends that the first argument is an object of type istream_iterator. This is wrong: It is an object of type istreambuf_iterator. Proposed resolution: Change 27.6.1.2.2 [lib.istream.formatted.arithmetic] from:
to
164. do_put() has apparently unused fill argumentSection: 22.2.5.3.2 [lib.locale.time.put.virtuals] Status: DR Submitter: Angelika Langer Date: 23 Jul 1999 In 22.2.5.3.2 [lib.locale.time.put.virtuals] 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. Proposed resolution: Add the following note after 22.2.5.3.2 [lib.locale.time.put.virtuals] paragraph 2:
Rationale: The LWG felt that while the normative text was correct, users need some guidance on what to pass for the fill argument since the standard doesn't say how it's used. 165. xsputn(), pubsync() never called by basic_ostream members?Section: 27.6.2.1 [lib.ostream] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 Paragraph 2 explicitly states that none of the basic_ostream 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 overflow(). Basically this is fine but this implies that sputn() (this function would call the virtual function xsputn()) is never called by any of the standard output functions. Is this really intended? At minimum it would be convenient to call xsputn() for strings... Also, the statement that overflow() is the only virtual member of basic_streambuf called is in conflict with the definition of flush() which calls rdbuf()->pubsync() and thereby the virtual function sync() (flush() is listed under "unformatted output functions"). In addition, I guess that the sentence starting with "They may use other public members of basic_ostream ..." probably was intended to start with "They may use other public members of basic_streamuf..." although the problem with the virtual members exists in both cases. I see two obvious resolutions:
Proposed resolution: Change the last sentence of 27.6.2.1 (lib.ostream) paragraph 2 from:
to:
[Kona: the LWG believes this is a problem. Wish to ask Jerry or PJP why the standard is written this way.] [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.] 168. Typo: formatted vs. unformattedSection: 27.6.2.6 [lib.ostream.unformatted] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The first paragraph begins with a descriptions what has to be done in formatted output functions. Probably this is a typo and the paragraph really want to describe unformatted output functions... Proposed resolution: In 27.6.2.6 [lib.ostream.unformatted] paragraph 1, the first and last sentences, change the word "formatted" to "unformatted":
169. Bad efficiency of overflow() mandatedSection: 27.7.1.3 [lib.stringbuf.virtuals] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 Paragraph 8, Notes, of this section seems to mandate an extremely inefficient way of buffer handling for basic_stringbuf, especially in view of the restriction that basic_ostream member functions are not allowed to use xsputn() (see 27.6.2.1 [lib.ostream]): For each character to be inserted, a new buffer is to be created. Of course, the resolution below requires some handling of simultaneous input and output since it is no longer possible to update egptr() whenever epptr() is changed. A possible solution is to handle this in underflow(). Proposed resolution: In 27.7.1.3 [lib.stringbuf.virtuals] paragraph 8, Notes, insert the words "at least" as in the following:
170. Inconsistent definition of traits_typeSection: 27.7.4 [lib.stringstream] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 The classes basic_stringstream (27.7.4 [lib.stringstream]), basic_istringstream (27.7.2 [lib.istringstream]), and basic_ostringstream (27.7.3 [lib.ostringstream]) are inconsistent in their definition of the type traits_type: For istringstream, this type is defined, for the other two it is not. This should be consistent. Proposed resolution: Proposed resolution: To the declarations of basic_ostringstream (27.7.3 [lib.ostringstream]) and basic_stringstream (27.7.4 [lib.stringstream]) add: typedef traits traits_type; 171. Strange seekpos() semantics due to joint positionSection: 27.8.1.4 [lib.filebuf.virtuals] Status: DR Submitter: Dietmar Kühl Date: 20 Jul 1999 Overridden virtual functions, seekpos() In 27.8.1.1 [lib.filebuf] paragraph 3, it is stated that a joint input and output position is maintained by basic_filebuf. Still, the description of seekpos() 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 ios_base::ate is set. However, I think, the standard should say something like this:
Plus the appropriate error handling, that is... Proposed resolution: Change the unnumbered paragraph in 27.8.1.4 (lib.filebuf.virtuals) before paragraph 14 from:
to:
[Kona: Dietmar is working on a proposed resolution.] [Post-Tokyo: Dietmar supplied the above wording.] 172. Inconsistent types for basic_istream::ignore()Section: 27.6.1.3 [lib.istream.unformatted] Status: DR Submitter: Greg Comeau, Dietmar Kühl Date: 23 Jul 1999 In 27.6.1.1 [lib.istream] the function ignore() gets an object of type streamsize as first argument. However, in 27.6.1.3 [lib.istream.unformatted] paragraph 23 the first argument is of type int. As far as I can see this is not really a contradiction because everything is consistent if streamsize is typedef to be int. However, this is almost certainly not what was intended. The same thing happened to basic_filebuf::setbuf(), as described in issue 173. 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. Proposed resolution: In 27.6.1.3 [lib.istream.unformatted] paragraph 23 and 24, change both uses of int in the description of ignore() to streamsize. 173. Inconsistent types for basic_filebuf::setbuf()Section: 27.8.1.4 [lib.filebuf.virtuals] Status: DR Submitter: Greg Comeau, Dietmar Kühl Date: 23 Jul 1999 In 27.8.1.1 [lib.filebuf] the function setbuf() gets an object of type streamsize as second argument. However, in 27.8.1.4 [lib.filebuf.virtuals] paragraph 9 the second argument is of type int. As far as I can see this is not really a contradiction because everything is consistent if streamsize is typedef to be int. However, this is almost certainly not what was intended. The same thing happened to basic_istream::ignore(), as described in issue 172. Proposed resolution: In 27.8.1.4 [lib.filebuf.virtuals] paragraph 9, change all uses of int in the description of setbuf() to streamsize. 174. Typo: OFF_T vs. POS_TSection: D.6 [depr.ios.members] Status: DR Submitter: Dietmar Kühl Date: 23 Jul 1999 According to paragraph 1 of this section, streampos is the type OFF_T, the same type as streamoff. However, in paragraph 6 the streampos gets the type POS_T Proposed resolution: Change D.6 [depr.ios.members] paragraph 1 from "typedef OFF_T streampos;" to "typedef POS_T streampos;" 175. Ambiguity for basic_streambuf::pubseekpos() and a few other functions.Section: D.6 [depr.ios.members] Status: DR Submitter: Dietmar Kühl Date: 23 Jul 1999 According to paragraph 8 of this section, the methods basic_streambuf::pubseekpos(), basic_ifstream::open(), and basic_ofstream::open "may" be overloaded by a version of this function taking the type ios_base::open_mode as last argument argument instead of ios_base::openmode (ios_base::open_mode 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. Proposed resolution: In D.6 [depr.ios.members] paragraph 8, remove the default arguments for basic_streambuf::pubseekpos(), basic_ifstream::open(), and basic_ofstream::open(). 176. exceptions() in ios_base...?Section: D.6 [depr.ios.members] Status: DR Submitter: Dietmar Kühl Date: 23 Jul 1999 The "overload" for the function exceptions() in paragraph 8 gives the impression that there is another function of this function defined in class ios_base. 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 [lib.input.output]." Proposed resolution: In D.6 [depr.ios.members] paragraph 8, move the declaration of the function exceptions()into class basic_ios. 181. make_pair() unintended behaviorSection: 20.2.2 [lib.pairs] Status: DR Submitter: Andrew Koenig Date: 3 Aug 1999 The claim has surfaced in Usenet that expressions such as Proposed resolution: In 20.2 [lib.utility], paragraph 1 change the following declaration of make_pair(): template <class T1, class T2> pair<T1,T2> make_pair(const T1&, const T2&); to: template <class T1, class T2> pair<T1,T2> make_pair(T1, T2); In 20.2.2 [lib.pairs] paragraph 7 and the line before, change: template <class T1, class T2> pair<T1, T2> make_pair(const T1& x, const T2& y); to: template <class T1, class T2> pair<T1, T2> make_pair(T1 x, T2 y); and add the following footnote to the effects clause:
Rationale: 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. 182. Ambiguous references to size_tSection: 17 [lib.library] Status: DR Submitter: Al Stevens Date: 15 Aug 1999 Many references to size_t throughout the document omit the std:: namespace qualification. For example, 17.4.3.4 [lib.replacement.functions] paragraph 2: operator new(size_t) operator new(size_t, const std::nothrow_t&) operator new[](size_t) operator new[](size_t, const std::nothrow_t&) Proposed resolution: In 17.4.3.4 [lib.replacement.functions] paragraph 2: replace:
by: - 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&) In [lib.allocator.requirements] 20.1.5, paragraph 4: replace:
by:
In [lib.allocator.members] 20.4.1.1, paragraphs 3 and 6: replace:
by:
In [lib.char.traits.require] 21.1.1, paragraph 1: replace:
by:
In [lib.char.traits.require] 21.1.1, table 37: replace the return type of X::length(p): "size_t" by "std::size_t". In [lib.std.iterator.tags] 24.3.3, paragraph 2: replace: In [lib.locale.ctype] 22.2.1.1 put namespace std { ...} around the declaration of template <class charT> class ctype. Rationale: The LWG believes correcting names like size_t and ptrdiff_t to std::size_t and std::ptrdiff_t 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 [lib.extern.types], 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. The issue is treated as a Defect Report to make explicit the Project Editor's authority to make this change. [Post-Tokyo: Nico Josuttis provided the above wording at the request of the LWG.] [Toronto: This is tangentially related to issue 229, but only tangentially: the intent of this issue is to address use of the name size_t in contexts outside of namespace std, such as in the description of ::operator new. The proposed changes should be reviewed to make sure they are correct.] [pre-Copenhagen: Nico has reviewed the changes and believes them to be correct.] 183. I/O stream manipulators don't work for wide character streamsSection: 27.6.3 [lib.std.manip] Status: DR Submitter: Andy Sawyer Date: 7 Jul 1999 27.6.3 [lib.std.manip] paragraph 3 says (clause numbering added for exposition):
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& ..." 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. e.g. wcout << setbase( 16 ); Must have value 'wcout' (which makes sense) and type 'ostream&' (which doesn't). 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. 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"& Proposed resolution: Replace section 27.6.3 [lib.std.manip] except paragraph 1 with the following:
[Kona: Andy Sawyer and Beman Dawes will work to improve the wording of the proposed resolution.] [Tokyo - The LWG noted that issue 216 involves the same paragraphs.] [Post-Tokyo: The issues list maintainer combined the proposed resolution of this issue with the proposed resolution for issue 216 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.] 184. numeric_limits<bool> wording problemsSection: 18.2.1.5 [lib.numeric.special] Status: DR Submitter: Gabriel Dos Reis Date: 21 Jul 1999 bools are defined by the standard to be of integer types, as per 3.9.1 [basic.fundamental] 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. 18.2.1.2/7 says numeric_limits<>::digits is, for built-in integer types, the number of non-sign bits in the representation. 4.5/4 states that a bool promotes to int ; whereas 4.12/1 says any non zero arithmetical value converts to true. I don't think it makes sense at all to require numeric_limits<bool>::digits and numeric_limits<bool>::digits10 to be meaningful. 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. I don't think it makes sense to require numeric_limits<bool>::is_signed to be meaningful. 18.2.1.2/18 for numeric_limits<integer_type>::radix says:
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 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. Furthermore, numeric_limits<bool>::is_modulo and numeric_limits<bool>::is_signed have similar problems. Proposed resolution: Append to the end of 18.2.1.5 [lib.numeric.special]:
[Tokyo: The LWG desires wording that specifies exact values rather than more general wording in the original proposed resolution.] [Post-Tokyo: At the request of the LWG in Tokyo, Nico Josuttis provided the above wording.] 185. Questionable use of term "inline"Section: 20.3 [lib.function.objects] Status: DR Submitter: UK Panel Date: 26 Jul 1999 Paragraph 4 of 20.3 [lib.function.objects] says:
(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. Indeed both:
and
take care to state that this may indeed NOT be the case. Thus the example "mandates" behavior that is explicitly not required elsewhere. Proposed resolution: In 20.3 [lib.function.objects] paragraph 1, remove the sentence:
Remove 20.3 [lib.function.objects] paragraph 2, which reads:
In 20.3 [lib.function.objects] paragraph 4, remove the sentence:
[Kona: The LWG agreed there was a defect.] [Tokyo: The LWG crafted the proposed resolution.] 186. bitset::set() second parameter should be boolSection: 23.3.5.2 [lib.bitset.members] Status: DR Submitter: Darin Adler Date: 13 Aug 1999 In section 23.3.5.2 [lib.bitset.members], 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. Proposed resolution: In 23.3.5 [lib.template.bitset] Para 1 Replace: bitset<N>& set(size_t pos, int val = true ); With: bitset<N>& set(size_t pos, bool val = true ); In 23.3.5.2 [lib.bitset.members] Para 12(.5) Replace: bitset<N>& set(size_t pos, int val = 1 ); With: bitset<N>& set(size_t pos, bool val = true ); [Kona: The LWG agrees with the description. Andy Sawyer will work on better P/R wording.] [Post-Tokyo: Andy provided the above wording.] Rationale: bool is a better choice. It is believed that binary compatibility is not an issue, because this member function is usually implemented as inline, 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. 189. setprecision() not specified correctlySection: 27.4.2.2 [lib.fmtflags.state] Status: DR Submitter: Andrew Koenig Date: 25 Aug 1999 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. Proposed resolution: Remove from 27.4.2.2 [lib.fmtflags.state], paragraph 9, the text "(number of digits after the decimal point)". 193. Heap operations description incorrectSection: 25.3.6 [lib.alg.heap.operations] Status: DR Submitter: Markus Mauhart Date: 24 Sep 1999 25.3.6 [lib.alg.heap.operations] states two key properties of a heap [a,b), the first of them
is Actually there are two independent changes:
Proposed resolution: Change 25.3.6 [lib.alg.heap.operations] property (1) from:
to:
195. Should basic_istream::sentry's constructor ever set eofbit?Section: 27.6.1.1.2 [lib.istream::sentry] Status: DR Submitter: Matt Austern Date: 13 Oct 1999 Suppose that is.flags() & ios_base::skipws is nonzero. What should basic_istream<>::sentry'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. On the one hand, nothing in 27.6.1.1.2 [lib.istream::sentry] says that basic_istream<>::sentry should ever set eofbit. On the other hand, 27.6.1.1 [lib.istream] paragraph 4 says that if extraction from a streambuf "returns traits::eof(), then the input function, except as explicitly noted otherwise, completes its actions and does setstate(eofbit)". So the question comes down to whether basic_istream<>::sentry's constructor is an input function. Comments from Jerry Schwarz:
Proposed resolution: Add a sentence to the end of 27.6.1.1.2 paragraph 2:
199. What does allocate(0) return?Section: 20.1.5 [lib.allocator.requirements] Status: DR Submitter: Matt Austern Date: 19 Nov 1999 Suppose that A is a class that conforms to the Allocator requirements of Table 32, and a is an object of class A What should be the return value of a.allocate(0)? Three reasonable possibilities: forbid the argument 0, return a null pointer, or require that the return value be a unique non-null pointer. Proposed resolution: Add a note to the allocate row of Table 32: "[Note: If n == 0, the return value is unspecified. --end note]" Rationale: 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. 208. Unnecessary restriction on past-the-end iteratorsSection: 24.1 [lib.iterator.requirements] Status: DR Submitter: Stephen Cleary Date: 02 Feb 2000 In 24.1 paragraph 5, it is stated ". . . Dereferenceable and past-the-end values are always non-singular." 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. Removing this restriction would allow, for example, a singly-linked list without a "footer" node. This would have an impact on existing code that expects past-the-end iterators obtained from different (generic) containers being not equal. Proposed resolution: Change 24.1 [lib.iterator.requirements] paragraph 5, the last sentence, from:
to:
Rationale: 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. 209. basic_string declarations inconsistentSection: 21.3 [lib.basic.string] Status: DR Submitter: Igor Stauder Date: 11 Feb 2000 In Section 21.3 [lib.basic.string] the basic_string member function declarations use a consistent style except for the following functions: void push_back(const charT); basic_string& assign(const basic_string&); void swap(basic_string<charT,traits,Allocator>&); - push_back, assign, swap: missing argument name Proposed resolution: In Section 21.3 [lib.basic.string] change the basic_string member function declarations push_back, assign, and swap to: void push_back(charT c); basic_string& assign(const basic_string& str); void swap(basic_string& str); Rationale: 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. 210. distance first and last confusedSection: 25 [lib.algorithms] Status: DR Submitter: Lisa Lippincott Date: 15 Feb 2000 In paragraph 9 of section 25 [lib.algorithms], it is written:
Proposed resolution: On the last line of paragraph 9 of section 25 [lib.algorithms] change "a-b" to "b-a". Rationale: 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. 211. operator>>(istream&, string&) doesn't set failbitSection: 21.3.7.9 [lib.string.io] Status: DR Submitter: Scott Snyder Date: 4 Feb 2000 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. This implies that the typical construction std::istream is; std::string str; ... while (is >> str) ... ; (which tests failbit) is not required to terminate at EOF. Furthermore, this is inconsistent with other extraction operators, which do include this requirement. (See sections 27.6.1.2 [lib.istream.formatted] and 27.6.1.3 [lib.istream.unformatted]), 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 [lib.string.io] paragraph 8.) Proposed resolution: Insert new paragraph after paragraph 2 in section 21.3.7.9 [lib.string.io]:
212. Empty range behavior unclear for several algorithmsSection: 25.3.7 [lib.alg.min.max] Status: DR Submitter: Nico Josuttis Date: 26 Feb 2000 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(). Proposed resolution: In 25.3.7 [lib.alg.min.max] - Minimum and maximum, paragraphs 7 and 9, append: Returns last if first==last. Rationale: 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. 214. set::find() missing const overloadSection: 23.3.3 [lib.set], 23.3.4 [lib.multiset] Status: DR Submitter: Judy Ward Date: 28 Feb 2000 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: iterator find(const key_type & x) const; Proposed resolution: Change the prototypes for find(), lower_bound(), upper_bound(), and equal_range() in section 23.3.3 [lib.set] and section 23.3.4 [lib.multiset] to each have two overloads: iterator find(const key_type & x); const_iterator find(const key_type & x) const;iterator lower_bound(const key_type & x); const_iterator lower_bound(const key_type & x) const;iterator upper_bound(const key_type & x); const_iterator upper_bound(const key_type & x) const;pair<iterator, iterator> equal_range(const key_type & x); pair<const_iterator, const_iterator> equal_range(const key_type & x) const; [Tokyo: At the request of the LWG, Judy Ward provided wording extending the proposed resolution to lower_bound, upper_bound, and equal_range.] 217. Facets example (Classifying Japanese characters) contains errorsSection: 22.2.8 [lib.facets.examples] Status: DR Submitter: Martin Sebor Date: 29 Feb 2000 The example in 22.2.8, paragraph 11 contains the following errors: 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). 2) In file filt.C, the definition of `JCtype::id' must be qualified with the name of the namespace `My'. 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'. Proposed resolution: Replace the "Classifying Japanese characters" example in 22.2.8, paragraph 11 with the following: #include <locale> 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() {} }; } // file: filt.C #include <iostream> #include <locale> #include "jctype" // above std::locale::id My::JCtype::id; // the static JCtype member declared above. 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; } 220. ~ios_base() usage valid?Section: 27.4.2.7 [lib.ios.base.cons] Status: DR Submitter: Jonathan Schilling, Howard Hinnant Date: 13 Mar 2000 The pre-conditions for the ios_base destructor are described in 27.4.2.7 paragraph 2:
But what is not clear is: If no callback functions were ever registered, does it matter whether the ios_base members were ever initialized? For instance, does this program have defined behavior: #include <ios>class D : public std::ios_base { };int main() { D d; } 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. 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? 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. Proposed resolution: Modify 27.4.2.7 paragraph 1 from
to
221. num_get<>::do_get stage 2 processing brokenSection: 22.2.2.1.2 [lib.facet.num.get.virtuals] Status: DR Submitter: Matt Austern Date: 14 Mar 2000 Stage 2 processing of numeric conversion is broken. 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. 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. Proposed resolution: In 22.2.2.1.2 paragraph 8, replace the line: static const char src[] = "0123456789abcdefABCDEF+-"; with the line: static const char src[] = "0123456789abcdefxABCDEFX+-"; Rationale: 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. 222. Are throw clauses necessary if a throw is already implied by the effects clause?Section: 17.3.1.3 [lib.structure.specifications] Status: DR Submitter: Judy Ward Date: 17 Mar 2000 Section 21.3.6.8 describes the basic_string::compare function this way: 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)) . 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 [lib.string.cons] paragraph 4. 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. So it seems there is an inconsistency in the standard -- are the "Effects" clauses correct, or are the "Throws" clauses missing? Proposed resolution: In 17.3.1.3 [lib.structure.specifications] 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:
Rationale: 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. 223. reverse algorithm should use iter_swap rather than swapSection: 25.2.9 [lib.alg.reverse] Status: DR Submitter: Dave Abrahams Date: 21 Mar 2000 Shouldn't the effects say "applies iter_swap to all pairs..."? Proposed resolution: In 25.2.9 [lib.alg.reverse], replace: Effects: For each non-negative integer i <= (last - first)/2, applies swap to all pairs of iterators first + i, (last - i) - 1. with: Effects: For each non-negative integer i <= (last - first)/2, applies iter_swap to all pairs of iterators first + i, (last - i) - 1. 224. clear() complexity for associative containers refers to undefined NSection: 23.1.2 [lib.associative.reqmts] Status: DR Submitter: Ed Brey Date: 23 Mar 2000 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. Proposed resolution: In the associative container requirements table in 23.1.2 paragraph 7, the complexity of a.clear(), change "log(size()) + N" to "linear in size()". Rationale: It's the "log(size())", not the "N", that is in error: there's no difference between O(N) and O(N + log(N)). The text in the standard is probably an incorrect cut-and-paste from the range version of erase. 227. std::swap() should require CopyConstructible or DefaultConstructible argumentsSection: 25.2.2 [lib.alg.swap] Status: DR Submitter: Dave Abrahams Date: 09 Apr 2000 25.2.2 reads:
The only reasonable** generic implementation of swap requires construction of a new temporary copy of one of its arguments: template<class T> void swap(T& a, T& b); { T tmp(a); a = b; b = tmp; } But a type which is only Assignable cannot be swapped by this implementation. **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: template<class T> void swap(T& a, T& b); { T tmp; tmp = a; a = b; b = tmp; } Proposed resolution: Change 25.2.2 paragraph 1 from:
to:
228. Incorrect specification of "..._byname" facetsSection: 22.2 [lib.locale.categories] Status: DR Submitter: Dietmar Kühl Date: 20 Apr 2000 The sections 22.2.1.2 [lib.locale.ctype.byname], 22.2.1.4 [lib.locale.ctype.byname.special], 22.2.1.6 [lib.locale.codecvt.byname], 22.2.3.2 [lib.locale.numpunct.byname], 22.2.4.2 [lib.locale.collate.byname], 22.2.5.4 [lib.locale.time.put.byname], 22.2.6.4 [lib.locale.moneypunct.byname], and 22.2.7.2 [lib.locale.messages.byname] 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'. 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. Proposed resolution: Change section 22.2.1.2 (lib.locale.ctype.byname) to become: 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 }; } Change section 22.2.1.6 (lib.locale.codecvt.byname) to become: 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 }; } Change section 22.2.3.2 (lib.locale.numpunct.byname) to become: 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 }; } Change section 22.2.4.2 (lib.locale.collate.byname) to become: 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 }; } Change section 22.2.5.2 (lib.locale.time.get.byname) to become: 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 explicit time_get_byname(const char*, size_t refs = 0); protected: ~time_get_byname(); // virtual }; } Change section 22.2.5.4 (lib.locale.time.put.byname) to become: 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; explicit time_put_byname(const char*, size_t refs = 0); protected: ~time_put_byname(); // virtual }; }" Change section 22.2.6.4 (lib.locale.moneypunct.byname) to become: 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; explicit moneypunct_byname(const char*, size_t refs = 0); protected: ~moneypunct_byname(); // virtual }; } Change section 22.2.7.2 (lib.locale.messages.byname) to become: namespace std { template <class charT> class messages_byname : public messages<charT> { public: typedef messages_base::catalog catalog; typedef basic_string<charT> string_type; explicit messages_byname(const char*, size_t refs = 0); protected: ~messages_byname(); // virtual }; } Remove section 22.2.1.4 [lib.locale.ctype.byname.special] completely (because in this case only those members are defined to be virtual which are defined to be virtual in 'ctype<cT>'.) [Post-Tokyo: Dietmar Kühl submitted this issue at the request of the LWG to solve the underlying problems raised by issue 138.] [Copenhagen: proposed resolution was revised slightly, to remove three last virtual functions from messages_byname.] 230. Assignable specified without also specifying CopyConstructibleSection: 17 [lib.library] Status: DR Submitter: Beman Dawes Date: 26 Apr 2000 Issue 227 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. 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 [lib.accumulate]. Proposed resolution: In 23.1 [lib.container.requirements] table 65 for value_type: change "T is Assignable" to "T is CopyConstructible and Assignable" In 23.1.2 [lib.associative.reqmts] table 69 X::key_type; change
"Key is Assignable" to "Key is
CopyConstructible and Assignable" In 24.1.2 [lib.output.iterators] paragraph 1, change:
to:
[Post-Tokyo: Beman Dawes submitted this issue at the request of the LWG. He asks that the 25.2.4 [lib.alg.replace] and 25.2.5 [lib.alg.fill] changes be studied carefully, as it is not clear that CopyConstructible is really a requirement and may be overspecification.] Rationale: 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. 232. "depends" poorly defined in 17.4.3.1Section: 17.4.3.1 [lib.reserved.names] Status: DR Submitter: Peter Dimov Date: 18 Apr 2000 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." 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'. The following code demonstrates the problem: #include <algorithm>template<class T> struct X { typedef T type; };namespace std { template<> void swap(::X<int>::type& i, ::X<int>::type& j); } Proposed resolution: Change "user-defined name" to "user-defined type". Rationale: This terminology is used in section 2.5.2 and 4.1.1 of The C++ Programming Language. 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? [Toronto: this may be related to issue 120.] [post-Toronto: Judy provided the above proposed resolution and rationale.] 234. Typos in allocator definitionSection: 20.4.1.1 [lib.allocator.members] Status: DR Submitter: Dietmar Kühl Date: 24 Apr 2000 In paragraphs 12 and 13 the effects of construct() and destruct() are described as returns but the functions actually return void. Proposed resolution: Substitute "Returns" by "Effect". 235. No specification of default ctor for reverse_iteratorSection: 24.4.1.1 [lib.reverse.iterator] Status: DR Submitter: Dietmar Kühl Date: 24 Apr 2000 The declaration of reverse_iterator lists a default constructor. However, no specification is given what this constructor should do. Proposed resolution: In section 24.4.1.3.1 [lib.reverse.iter.cons] add the following paragraph:
[pre-Copenhagen: Dietmar provide wording for proposed resolution.] 237. Undefined expression in complexity specificationSection: 23.2.2.1 [lib.list.cons] Status: DR Submitter: Dietmar Kühl Date: 24 Apr 2000 The complexity specification in paragraph 6 says that the complexity is linear in first - last. Even if operator-() is defined on iterators this term is in general undefined because it would have to be last - first. Proposed resolution: Change paragraph 6 from Linear in first - last. to become Linear in distance(first, last). 238. Contradictory results of stringbuf initialization.Section: 27.7.1.1 [lib.stringbuf.cons] Status: DR Submitter: Dietmar Kühl Date: 11 May 2000 In 27.7.1.1 paragraph 4 the results of calling the constructor of 'basic_stringbuf' are said to be str() == str. This is fine that far but consider this code: std::basic_stringbuf<char> sbuf("hello, world", std::ios_base::openmode(0)); std::cout << "'" << sbuf.str() << "'\n"; 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 str() either returns the input or the output sequence. None of them is initialized, ie. both are empty, in which case the return from str() is defined to be basic_string<cT>(). However, probably only test cases in some testsuites will detect this "problem"... Proposed resolution: Remove 27.7.1.1 paragraph 4. Rationale: 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. 242. Side effects of function objectsSection: 25.2.3 [lib.alg.transform], 26.4 [lib.numeric.ops] Status: DR Submitter: Angelika Langer Date: May 15 2000 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. The standard defines a side effect in 1.9 [intro.execution] as: -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. 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. 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. 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): 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]). 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. 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. Proposed resolution: Things to notice about these changes:
Change 25.2.3/2 from: -2- Requires: op and binary_op shall not have any side effects. to: -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] Change 25.2.3/2 from: -2- Requires: op and binary_op shall not have any side effects. to: -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] Change 26.4.1/2 from: -2- Requires: T must meet the requirements of CopyConstructible (lib.copyconstructible) and Assignable (lib.container.requirements) types. binary_op shall not cause side effects. to: -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] Change 26.4.2/2 from: -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. to: -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] Change 26.4.3/4 from: -4- Requires: binary_op is expected not to have any side effects. to: -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] Change 26.4.4/2 from: -2- Requires: binary_op shall not have any side effects. to: -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] [Toronto: Dave Abrahams supplied wording.] [Copenhagen: Proposed resolution was modified slightly. Matt added footnotes pointing out that the use of closed ranges was intentional.] 243. get and getline when sentry reports failureSection: 27.6.1.3 [lib.istream.unformatted] Status: DR Submitter: Martin Sebor Date: May 15 2000 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. 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? 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). Proposed resolution: Add to 27.6.1.3, p1 after the sentence "... If the sentry object returns true, when converted to a value of type bool, the function endeavors to obtain the requested input." the following "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." Rationale: Although the general philosophy of the input functions is that the argument should not be modified upon failure, getline 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. 248. time_get fails to set eofbitSection: 22.2.5 [lib.category.time] Status: DR Submitter: Martin Sebor Date: 22 June 2000 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. Proposed resolution: Add paragraph 2 to section 22.2.5.1 with the following text: If the end iterator is reached during parsing by any of the get() member functions, the member sets ios_base::eofbit in err. Rationale: 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. 250. splicing invalidates iteratorsSection: 23.2.2.4 [lib.list.ops] Status: DR Submitter: Brian Parker Date: 14 Jul 2000 Section 23.2.2.4 [lib.list.ops] states that void splice(iterator position, list<T, Allocator>& x); invalidates all iterators and references to list x. This is unnecessary and defeats an important feature of splice. In fact, the SGI STL guarantees that iterators to x remain valid after splice. Proposed resolution: Add a footnote to 23.2.2.4 [lib.list.ops], paragraph 1: [Footnote: As specified in 20.1.5 [lib.allocator.requirements], paragraphs 4-5, the semantics described in this clause applies only to the case where allocators compare equal. --end footnote] In 23.2.2.4 [lib.list.ops], replace paragraph 4 with: 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. In 23.2.2.4 [lib.list.ops], replace paragraph 7 with: 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. In 23.2.2.4 [lib.list.ops], replace paragraph 12 with: 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. [pre-Copenhagen: Howard provided wording.] Rationale: 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 [lib.allocator.requirements] paragraph 4, the behavior of list when allocators compare nonequal is outside the scope of the standard. 251. basic_stringbuf missing allocator_typeSection: 27.7.1 [lib.stringbuf] Status: DR Submitter: Martin Sebor Date: 28 Jul 2000 The synopsis for the template class basic_stringbuf doesn't list a typedef for the template parameter Allocator. 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 Allocator parameter. Proposed resolution: 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: typedef Allocator allocator_type; 252. missing casts/C-style casts used in iostreamsSection: 27.7 [lib.string.streams] Status: DR Submitter: Martin Sebor Date: 28 Jul 2000 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. C-style casts have not been deprecated, so the first part of this issue is stylistic rather than a matter of correctness. Proposed resolution: In 27.7.2.2, p1 replace -1- Returns: (basic_stringbuf<charT,traits,Allocator>*)&sb. with -1- Returns: const_cast<basic_stringbuf<charT,traits,Allocator>*>(&sb). In 27.7.3.2, p1 replace -1- Returns: (basic_stringbuf<charT,traits,Allocator>*)&sb. with -1- Returns: const_cast<basic_stringbuf<charT,traits,Allocator>*>(&sb). In 27.7.6, p1, replace -1- Returns: &sb with -1- Returns: const_cast<basic_stringbuf<charT,traits,Allocator>*>(&sb). In D.7.2.2, p1 replace -2- Returns: &sb. with -2- Returns: const_cast<strstreambuf*>(&sb). 256. typo in 27.4.4.2, p17: copy_event does not existSection: 27.4.4.2 [lib.basic.ios.members] Status: DR Submitter: Martin Sebor Date: 21 Aug 2000 27.4.4.2, p17 says -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). The name copy_event isn't defined anywhere. The intended name was copyfmt_event. Proposed resolution: Replace copy_event with copyfmt_event in the named paragraph. 259. basic_string::operator[] and const correctnessSection: 21.3.4 [lib.string.access] Status: DR Submitter: Chris Newton Date: 27 Aug 2000 Paraphrased from a message that Chris Newton posted to comp.std.c++: The standard's description of basic_string<>::operator[] seems to violate const correctness. The standard (21.3.4/1) says that "If pos < size(), returns data()[pos]." The types don't work. The return value of data() is const charT*, but operator[] has a non-const version whose return type is reference. Proposed resolution: In section 21.3.4, paragraph 1, change "data()[pos]" to "*(begin() + pos)". 260. Inconsistent return type of istream_iterator::operator++(int)Section: 24.5.1.2 [lib.istream.iterator.ops] Status: DR Submitter: Martin Sebor Date: 27 Aug 2000 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. Proposed resolution: Change the declaration in 24.5.1.2, p5 from istream_iterator<T,charT,traits,Distance>& operator++(int); to istream_iterator<T,charT,traits,Distance> operator++(int); (that is, remove the `&'). 261. Missing description of istream_iterator::operator!=Section: 24.5.1.2 [lib.istream.iterator.ops] Status: DR Submitter: Martin Sebor Date: 27 Aug 2000 24.5.1, p3 lists the synopsis for 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); but there is no description of what the operator does (i.e., no Effects or Returns clause) in 24.5.1.2. Proposed resolution: Add paragraph 7 to the end of section 24.5.1.2 with the following text: 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); -7- Returns: !(x == y). 262. Bitmask operator ~ specified incorrectlySection: 17.3.2.1.2 [lib.bitmask.types] Status: DR Submitter: Beman Dawes Date: 03 Sep 2000 The ~ operation should be applied after the cast to int_type. Proposed resolution: Change 17.3.2.1.2 [lib.bitmask.types] operator~ from: bitmask operator~ ( bitmask X ) { return static_cast< bitmask>(static_cast<int_type>(~ X)); } to: bitmask operator~ ( bitmask X ) { return static_cast< bitmask>(~static_cast<int_type>(X)); } 263. Severe restriction on basic_string reference countingSection: 21.3 [lib.basic.string] Status: DR Submitter: Kevlin Henney Date: 04 Sep 2000 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). 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: // 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; Similarly, in the following example: // 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++; 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. Proposed resolution: Change the following sentence in 21.3 paragraph 5 from 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(). to 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(). 264. Associative container insert(i, j) complexity requirements are not feasible.Section: 23.1.2 [lib.associative.reqmts] Status: DR Submitter: John Potter Date: 07 Sep 2000 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. Related issue: 102 Proposed resolution: 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". [Copenhagen: Minor fix in proposed resolution: fixed unbalanced parens in the revised wording.] Rationale: 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. 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. 265. std::pair::pair() effects overly restrictiveSection: 20.2.2 [lib.pairs] Status: DR Submitter: Martin Sebor Date: 11 Sep 2000 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]. I believe that the the CopyConstructible requirement is unnecessary in the case of 20.2.2, p2. Proposed resolution: Change the Effects clause in 20.2.2, p2 from -2- Effects: Initializes its members as if implemented: pair() : first(T1()), second(T2()) {} to -2- Effects: Initializes its members as if implemented: pair() : first(), second() {} Rationale: 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. 266. bad_exception::~bad_exception() missing Effects clauseSection: 18.6.2.1 [lib.bad.exception] Status: DR Submitter: Martin Sebor Date: 24 Sep 2000 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). Proposed resolution: Remove the destructor from the class synopses of bad_alloc (18.4.2.1 [lib.bad.alloc]), bad_cast (18.5.2 [lib.bad.cast]), bad_typeid (18.5.3 [lib.bad.typeid]), and bad_exception (18.6.2.1 [lib.bad.exception]). Rationale: 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. 268. Typo in locale synopsisSection: 22.1.1 [lib.locale] Status: DR Submitter: Martin Sebor Date: 5 Oct 2000 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. Proposed resolution: Add the missing semicolons, i.e., change // construct/copy/destroy: locale() throw() locale(const locale& other) throw() in the synopsis in 22.1.1 to // construct/copy/destroy: locale() throw(); locale(const locale& other) throw(); 271. basic_iostream missing typedefsSection: 27.6.1.5 [lib.iostreamclass] Status: DR Submitter: Martin Sebor Date: 02 Nov 2000 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. Proposed resolution: Add the following to basic_iostream's class synopsis in 27.6.1.5 [lib.iostreamclass], immediately after public: // 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; 272. Missing parentheses around subexpressionSection: 27.4.4.3 [lib.iostate.flags] Status: DR Submitter: Martin Sebor Date: 02 Nov 2000 27.4.4.3, p4 says about the postcondition of the function: If rdbuf()!=0 then state == rdstate(); otherwise rdstate()==state|ios_base::badbit. 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. Proposed resolution: Add parentheses like so: rdstate()==(state|ios_base::badbit). 273. Missing ios_base qualification on members of a dependent classSection: 27 [lib.input.output] Status: DR Submitter: Martin Sebor Date: 02 Nov 2000 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. Proposed resolution: Qualify the names with the name of the class of which they are members, i.e., ios_base. 275. Wrong type in num_get::get() overloadsSection: 22.2.2.1.1 [lib.facet.num.get.members] Status: DR Submitter: Matt Austern Date: 02 Nov 2000 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:
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:
These two lists are not identical. They should be, since get is supposed to call do_get with exactly the arguments it was given. Proposed resolution: In 22.2.2.1.1 [lib.facet.num.get.members], change iter_type get(iter_type in, iter_type end, ios_base& str, ios_base::iostate& err, short& val) const; to iter_type get(iter_type in, iter_type end, ios_base& str, ios_base::iostate& err, float& val) const; 281. std::min() and max() requirements overly restrictiveSection: 25.3.7 [lib.alg.min.max] Status: DR Submitter: Martin Sebor Date: 02 Dec 2000 The requirements in 25.3.7, p1 and 4 call for T to satisfy the requirements of LessThanComparable (20.1.2 [lib.lessthancomparable]) and CopyConstructible (20.1.3 [lib.copyconstructible]). Since the functions take and return their arguments and result by const reference, I believe the CopyConstructible requirement is unnecessary. Proposed resolution: Remove the CopyConstructible requirement. Specifically, replace 25.3.7, p1 with -1- Requires: Type T is LessThanComparable (20.1.2 [lib.lessthancomparable]). and replace 25.3.7, p4 with -4- Requires: Type T is LessThanComparable (20.1.2 [lib.lessthancomparable]). 285. minor editorial errors in fstream ctorsSection: 27.8.1.6 [lib.ifstream.cons] Status: DR Submitter: Martin Sebor Date: 31 Dec 2000 27.8.1.6 [lib.ifstream.cons], p2, 27.8.1.9 [lib.ofstream.cons], p2, and 27.8.1.12 [lib.fstream.cons], p2 say about the effects of each constructor: ... If that function returns a null pointer, calls setstate(failbit) (which may throw ios_base::failure). The parenthetical note doesn't apply since the ctors cannot throw an exception due to the requirement in 27.4.4.1 [lib.basic.ios.cons], p3 that exceptions() be initialized to ios_base::goodbit. Proposed resolution: Strike the parenthetical note from the Effects clause in each of the paragraphs mentioned above. 286. <cstdlib> requirements missing size_t typedefSection: 25.4 [lib.alg.c.library] Status: DR Submitter: Judy Ward Date: 30 Dec 2000 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. Proposed resolution: Add the type size_t to Table 78 (section 25.4) and add the type size_t <cstdlib> to Table 97 (section C.2). Rationale: Since size_t is in <stdlib.h>, it must also be in <cstdlib>. 288. <cerrno> requirements missing macro EILSEQSection: 19.3 [lib.errno] Status: DR Submitter: Judy Ward Date: 30 Dec 2000 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" ISO/IEC 14882:1998(E) section 19.3 does not refer to the above amendment. Proposed resolution: Update Table 26 (section 19.3) "Header <cerrno> synopsis" and Table 95 (section C.2) "Standard Macros" to include EILSEQ. 292. effects of a.copyfmt (a)Section: 27.4.4.2 [lib.basic.ios.members] Status: DR Submitter: Martin Sebor Date: 05 Jan 2001 The Effects clause of the member function copyfmt() 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 (this == &rhs). If the two arguments are identical there is no need to copy any of the data members or call any callbacks registered with register_callback(). Also, as Howard Hinnant points out in message c++std-lib-8149 it appears to be incorrect to allow the object to fire erase_event followed by copyfmt_event since the callback handling the latter event may inadvertently attempt to access memory freed by the former. Proposed resolution: Change the Effects clause in 27.4.4.2, p15 from -15- Effects:Assigns to the member objects of *this the corresponding member objects of rhs, except that... to -15- Effects:If (this == &rhs) does nothing. Otherwise assigns to the member objects of *this the corresponding member objects of rhs, except that... 295. Is abs defined in <cmath>?Section: 26.5 [lib.c.math] Status: DR Submitter: Jens Maurer Date: 12 Jan 2001 Table 80 lists the contents of the <cmath> header. It does not list abs(). However, 26.5, paragraph 6, which lists added signatures present in <cmath>, does say that several overloads of abs() should be defined in <cmath>. Proposed resolution: Add abs to Table 80. Also, remove the parenthetical list of functions "(abs(), div(), rand(), srand())" from 26.5 [lib.c.math], paragraph 1. [Copenhagen: Modified proposed resolution so that it also gets rid of that vestigial list of functions in paragraph 1.] Rationale: All this DR does is fix a typo; it's uncontroversial. A separate question is whether we're doing the right thing in putting some overloads in <cmath> that we aren't also putting in <cstdlib>. That's issue 323. 297. const_mem_fun_t<>::argument_type should be const T*Section: 20.3.8 [lib.member.pointer.adaptors] Status: DR Submitter: Martin Sebor Date: 6 Jan 2001 The class templates const_mem_fun_t in 20.3.8, p8 and const_mem_fun1_t in 20.3.8, p9 derive from unary_function<T*, S>, and binary_function<T*, A, S>, respectively. Consequently, their argument_type, and first_argument_type members, respectively, are both defined to be T* (non-const). However, their function call member operator takes a const T* argument. It is my opinion that argument_type should be const T* 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:
template <class T>
struct X { /* ... */ };
int main ()
#1 foo() takes a plain unqualified X* as an argument
Proposed resolution: Replace the top portion of the definition of the class template const_mem_fun_t in 20.3.8, p8
template <class S, class T> class const_mem_fun_t
with
template <class S, class T> class const_mem_fun_t
Also replace the top portion of the definition of the class template const_mem_fun1_t in 20.3.8, p9
template <class S, class T, class A> class const_mem_fun1_t
with
template <class S, class T, class A> class const_mem_fun1_t
Rationale: This is simply a contradiction: the argument_type typedef, and the argument type itself, are not the same. 298. ::operator delete[] requirement incorrect/insufficientSection: 18.4.1.2 [lib.new.delete.array] Status: DR Submitter: John A. Pedretti Date: 10 Jan 2001 The default behavior of operator delete[] described in 18.4.1.2, p12 - namely that for non-null value of ptr, the operator reclaims storage allocated by the earlier call to the default operator new[] - is not correct in all cases. Since the specified operator new[] default behavior is to call operator new (18.4.1.2, p4, p8), which can be replaced, along with operator delete, by the user, to implement their own memory management, the specified default behavior of operator delete[] must be to call operator delete. Proposed resolution: Change 18.4.1.2, p12 from -12- Default behavior: to -12- Default behavior: Calls operator delete(ptr) or operator delete(ptr, std::nothrow) respectively. and expunge paragraph 13. 301. basic_string template ctor effects clause omits allocator argumentSection: 21.3.1 [lib.string.cons] Status: DR Submitter: Martin Sebor Date: 27 Jan 2001 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. Proposed resolution: Replace
with
303. Bitset input operator underspecifiedSection: 23.3.5.3 [lib.bitset.operators] Status: DR Submitter: Matt Austern Date: 5 Feb 2001 In 23.3.5.3, we are told that bitset's input operator "Extracts up to N (single-byte) characters from is.", where is is a stream of type basic_istream<charT, traits>. The standard does not say what it means to extract single byte characters from a stream whose character type, charT, is in general not a single-byte character type. Existing implementations differ. A reasonable solution will probably involve widen() and/or narrow(), since they are the supplied mechanism for converting a single character between char and arbitrary charT. Narrowing the input characters is not the same as widening the literals '0' and '1', because there may be some locales in which more than one wide character maps to the narrow character '0'. Narrowing means that alternate representations may be used for bitset input, widening means that they may not be. Note that for numeric input, num_get<> (22.2.2.1.2/8) compares input characters to widened version of narrow character literals. From Pete Becker, in c++std-lib-8224:
From Jens Maurer, in c++std-lib-8233:
Proposed resolution: Replace the first two sentences of paragraph 5 with: Extracts up to N characters from is. Stores these characters in a temporary object str of type basic_string<charT, traits>, then evaluates the expression x = bitset<N>(str). Replace the third bullet item in paragraph 5 with:
Rationale: Input for bitset should work the same way as numeric input. Using widen does mean that alternative digit representations will not be recognized, but this was a known consequence of the design choice. 306. offsetof macro and non-POD typesSection: 18.1 [lib.support.types] Status: DR Submitter: Steve Clamage Date: 21 Feb 2001 Spliced together from reflector messages c++std-lib-8294 and -8295: 18.1, paragraph 5, reads: "The macro offsetof accepts a restricted set of type arguments in this International Standard. type 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." For the POD requirement, it doesn't say "no diagnostic required" or "undefined behavior". I read 1.4 [intro.compliance], 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. Proposed resolution: Change 18.1, paragraph 5, to "If type is not a POD structure or a POD union the results are undefined." [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.] 307. Lack of reference typedefs in container adaptorsSection: 23.2.3 [lib.container.adaptors] Status: DR Submitter: Howard Hinnant Date: 13 Mar 2001 From reflector message c++std-lib-8330. See also lib-8317. The standard is currently inconsistent in 23.2.3.2 [lib.priority.queue] paragraph 1 and 23.2.3.3 [lib.stack] paragraph 1. 23.2.3.3/1, for example, says: -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. 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. This is a contradiction that can be fixed by:
I propose 3. This does not preclude option 2 if we choose to do it later (see issue 96); 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. Proposed resolution: 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: Change 23.2.3.1/1 from: 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(); } }; to: 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(); } }; Change 23.2.3.2/1 from: 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 } to: 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 } And change 23.2.3.3/1 from: 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); } to: 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); } [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.] 308. Table 82 mentions unrelated headersSection: 27 [lib.input.output] Status: DR Submitter: Martin Sebor Date: 15 Mar 2001 Table 82 in section 27 mentions the header <cstdlib> for String streams (27.7 [lib.string.streams]) and the headers <cstdio> and <cwchar> for File streams (27.8 [lib.file.streams]). 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 [lib.contents], only such headers are to be listed in the summary. Proposed resolution: Remove <cstdlib> and <cwchar> from Table 82. [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 [lib.file.streams], including 27.8.2 [lib.c.files].] 312. Table 27 is missing headersSection: 20 [lib.utilities] Status: DR Submitter: Martin Sebor Date: 29 Mar 2001 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 [lib.c.malloc]. Proposed resolution: Add <cstdlib> and <cstring> to Table 27, in the same row as <memory>. ----- End of document ----- |