Bugs

Bugs
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Implementation Bugs

+ Information on known bugs, details on efforts to fix them, and + fixed bugs are all available as part of the GCC bug tracking system, + with the category set to libstdc++. +

Standard Bugs

+ Everybody's got issues. Even the C++ Standard Library. +

+ The Library Working Group, or LWG, is the ISO subcommittee responsible + for making changes to the library. They periodically publish an + Issues List containing problems and possible solutions. As they reach + a consensus on proposed solutions, we often incorporate the solution. +

+ Here are the issues which have resulted in code changes to the library. + The links are to the specific defect reports from a partial + copy of the Issues List. You can read the full version online + at the ISO C++ + Committee homepage, linked to on the + GCC "Readings" + page. If + you spend a lot of time reading the issues, we recommend downloading + the ZIP file and reading them locally. +

+ (NB: partial copy means that not all + links within the lwg-*.html pages will work. Specifically, + links to defect reports that have not been accorded full DR + status will probably break. Rather than trying to mirror the + entire issues list on our overworked web server, we recommend + you go to the LWG homepage instead.) +

+ If a DR is not listed here, we may simply not have gotten to + it yet; feel free to submit a patch. Search the include/bits + and src directories for appearances of + _GLIBCXX_RESOLVE_LIB_DEFECTS for examples + of style. Note that we usually do not make changes to the + code until an issue has reached DR status. +

5: + string::compare specification questionable +: This should be two overloaded functions rather than a single function. +
17: + Bad bool parsing +: Apparently extracting Boolean values was messed up... +
19: + "Noconv" definition too vague +: If codecvt::do_in returns noconv there are + no changes to the values in [to, to_limit). +
22: + Member open vs flags +: Re-opening a file stream does not clear the state flags. +
23: + Num_get overflow result +: Implement the proposed resolution. +
25: + String operator<< uses width() value wrong +: Padding issues. +
48: + Use of non-existent exception constructor +: An instance of ios_base::failure is constructed instead. +
49: + Underspecification of ios_base::sync_with_stdio +: The return type is the previous state of synchronization. +
50: + Copy constructor and assignment operator of ios_base +: These members functions are declared private and are + thus inaccessible. Specifying the correct semantics of + "copying stream state" was deemed too complicated. +
60: + What is a formatted input function? +: This DR made many widespread changes to basic_istream + and basic_ostream all of which have been implemented. +
63: + Exception-handling policy for unformatted output +: Make the policy consistent with that of formatted input, unformatted + input, and formatted output. +
68: + Extractors for char* should store null at end +: And they do now. An editing glitch in the last item in the list of + [27.6.1.2.3]/7. +
74: + Garbled text for codecvt::do_max_length +: The text of the standard was gibberish. Typos gone rampant. +
75: + Contradiction in codecvt::length's argument types +: Change the first parameter to stateT& and implement + the new effects paragraph. +
83: + string::npos vs. string::max_size() +: Safety checks on the size of the string should test against + max_size() rather than npos. +
90: + Incorrect description of operator>> for strings +: The effect contain isspace(c,getloc()) which must be + replaced by isspace(c,is.getloc()). +
91: + Description of operator>> and getline() for string<> + might cause endless loop +: They behave as a formatted input function and as an unformatted + input function, respectively (except that getline is + not required to set gcount). +
103: + set::iterator is required to be modifiable, but this allows + modification of keys. +: For associative containers where the value type is the same as + the key type, both iterator and const_iterator + are constant iterators. +
109: + Missing binders for non-const sequence elements +: The binder1st and binder2nd didn't have an + operator() taking a non-const parameter. +
110: + istreambuf_iterator::equal not const +: This was not a const member function. Note that the DR says to + replace the function with a const one; we have instead provided an + overloaded version with identical contents. +
117: + basic_ostream uses nonexistent num_put member functions +: num_put::put() was overloaded on the wrong types. +
118: + basic_istream uses nonexistent num_get member functions +: Same as 117, but for num_get::get(). +
129: + Need error indication from seekp() and seekg() +: These functions set failbit on error now. +
130: + Return type of container::erase(iterator) differs for associative containers +: Make member erase return iterator for set, multiset, map, multimap. +
136: + seekp, seekg setting wrong streams? +: seekp should only set the output stream, and + seekg should only set the input stream. +
167: + Improper use of traits_type::length() +: op<< with a const char* was + calculating an incorrect number of characters to write. +
169: + Bad efficiency of overflow() mandated +: Grow efficiently the internal array object. +
171: + Strange seekpos() semantics due to joint position +: Quite complex to summarize... +
181: + make_pair() unintended behavior +: This function used to take its arguments as reference-to-const, now + it copies them (pass by value). +
195: + Should basic_istream::sentry's constructor ever set eofbit? +: Yes, it can, specifically if EOF is reached while skipping whitespace. +
211: + operator>>(istream&, string&) doesn't set failbit +: If nothing is extracted into the string, op>> now + sets failbit (which can cause an exception, etc., etc.). +
214: + set::find() missing const overload +: Both set and multiset were missing + overloaded find, lower_bound, upper_bound, and equal_range functions + for const instances. +
231: + Precision in iostream? +: For conversion from a floating-point type, str.precision() + is specified in the conversion specification. +
233: + Insertion hints in associative containers +: Implement N1780, first check before then check after, insert as close + to hint as possible. +
235: + No specification of default ctor for reverse_iterator +: The declaration of reverse_iterator lists a default constructor. + However, no specification is given what this constructor should do. +
241: + Does unique_copy() require CopyConstructible and Assignable? +: Add a helper for forward_iterator/output_iterator, fix the existing + one for input_iterator/output_iterator to not rely on Assignability. +
243: + get and getline when sentry reports failure +: Store a null character only if the character array has a non-zero size. +
251: + basic_stringbuf missing allocator_type +: This nested typedef was originally not specified. +
253: + valarray helper functions are almost entirely useless +: Make the copy constructor and copy-assignment operator declarations + public in gslice_array, indirect_array, mask_array, slice_array; provide + definitions. +
265: + std::pair::pair() effects overly restrictive +: The default ctor would build its members from copies of temporaries; + now it simply uses their respective default ctors. +
266: + bad_exception::~bad_exception() missing Effects clause +: The bad_* classes no longer have destructors (they + are trivial), since no description of them was ever given. +
271: + basic_iostream missing typedefs +: The typedefs it inherits from its base classes can't be used, since + (for example) basic_iostream<T>::traits_type is ambiguous. +
275: + Wrong type in num_get::get() overloads +: Similar to 118. +
280: + Comparison of reverse_iterator to const reverse_iterator +: Add global functions with two template parameters. + (NB: not added for now a templated assignment operator) +
292: + Effects of a.copyfmt (a) +: If (this == &rhs) do nothing. +
300: + List::merge() specification incomplete +: If (this == &x) do nothing. +
303: + Bitset input operator underspecified +: Basically, compare the input character to + is.widen(0) and is.widen(1). +
305: + Default behavior of codecvt<wchar_t, char, + mbstate_t>::length() +: Do not specify what codecvt<wchar_t, char, + mbstate_t>::do_length must return. +
328: + Bad sprintf format modifier in + money_put<>::do_put() +: Change the format string to "%.0Lf". +
365: + Lack of const-qualification in clause 27 +: Add const overloads of is_open. +
387: + std::complex over-encapsulated +: Add the real(T) and imag(T) + members; in C++0x mode, also adjust the existing + real() and imag() members and + free functions. +
389: + Const overload of valarray::operator[] returns + by value +: Change it to return a const T&. +
396: + what are characters zero and one +: Implement the proposed resolution. +
402: + Wrong new expression in [some_]allocator::construct +: Replace "new" with "::new". +
408: + + Is vector<reverse_iterator<char*> > forbidden? + +: Tweak the debug-mode checks in _Safe_iterator. +
409: + Closing an fstream should clear the error state +: Have open clear the error flags. +
431: + Swapping containers with unequal allocators +: Implement Option 3, as per N1599. +
432: + stringbuf::overflow() makes only one write position + available +: Implement the resolution, beyond DR 169. +
434: + bitset::to_string() hard to use +: Add three overloads, taking fewer template arguments. +
438: + Ambiguity in the "do the right thing" clause +: Implement the resolution, basically cast less. +
453: + basic_stringbuf::seekoff need not always fail for an empty stream +: Don't fail if the next pointer is null and newoff is zero. +
455: + cerr::tie() and wcerr::tie() are overspecified +: Initialize cerr tied to cout and wcerr tied to wcout. +
464: + Suggestion for new member functions in standard containers +: Add data() to std::vector and + at(const key_type&) to std::map. +
508: + Bad parameters for ranlux64_base_01 +: Fix the parameters. +
512: + Seeding subtract_with_carry_01 from a single unsigned long +: Construct a linear_congruential engine and seed with it. +
526: + Is it undefined if a function in the standard changes in + parameters? +: Use &value. +
538: + 241 again: Does unique_copy() require CopyConstructible + and Assignable? +: In case of input_iterator/output_iterator rely on Assignability of + input_iterator' value_type. +
539: + partial_sum and adjacent_difference should mention + requirements +: We were almost doing the right thing, just use std::move + in adjacent_difference. +
541: + shared_ptr template assignment and void +: Add an auto_ptr<void> specialization. +
543: + valarray slice default constructor +: Follow the straightforward proposed resolution. +
550: + What should the return type of pow(float,int) be? +: In C++0x mode, remove the pow(float,int), etc., signatures. +
586: + string inserter not a formatted function +: Change it to be a formatted output function (i.e. catch exceptions). +
596: + 27.8.1.3 Table 112 omits "a+" and "a+b" modes +: Add the missing modes to fopen_mode. +
630: + arrays of valarray +: Implement the simple resolution. +
660: + Missing bitwise operations +: Add the missing operations. +
691: + const_local_iterator cbegin, cend missing from TR1 +: In C++0x mode add cbegin(size_type) and cend(size_type) + to the unordered containers. +
693: + std::bitset::all() missing +: Add it, consistently with the discussion. +
695: + ctype<char>::classic_table() not accessible +: Make the member functions table and classic_table public. +
696: + istream::operator>>(int&) broken +: Implement the straightforward resolution. +
761: + unordered_map needs an at() member function +: In C++0x mode, add at() and at() const. +
775: + Tuple indexing should be unsigned? +: Implement the int -> size_t replacements. +
776: + Undescribed assign function of std::array +: In C++0x mode, remove assign, add fill. +
781: + std::complex should add missing C99 functions +: In C++0x mode, add std::proj. +
809: + std::swap should be overloaded for array types +: Add the overload. +
844: + complex pow return type is ambiguous +: In C++0x mode, remove the pow(complex<T>, int) signature. +
853: + to_string needs updating with zero and one +: Update / add the signatures. +
865: + More algorithms that throw away information +: The traditional HP / SGI return type and value is blessed + by the resolution of the DR. +

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