1 // Locale support -*- C++ -*-
2
3 // Copyright (C) 1997-2023 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /** @file bits/locale_classes.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{locale}
28 */
29
30 //
31 // ISO C++ 14882: 22.1 Locales
32 //
33
34 #ifndef _LOCALE_CLASSES_H
35 #define _LOCALE_CLASSES_H 1
36
37 #pragma GCC system_header
38
39 #include <bits/localefwd.h>
40 #include <string>
41 #include <ext/atomicity.h>
42
43 namespace std _GLIBCXX_VISIBILITY(default)
44 {
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
46
47 // 22.1.1 Class locale
48 /**
49 * @brief Container class for localization functionality.
50 * @ingroup locales
51 *
52 * The locale class is first a class wrapper for C library locales. It is
53 * also an extensible container for user-defined localization. A locale is
54 * a collection of facets that implement various localization features such
55 * as money, time, and number printing.
56 *
57 * Constructing C++ locales does not change the C library locale.
58 *
59 * This library supports efficient construction and copying of locales
60 * through a reference counting implementation of the locale class.
61 */
62 class locale
63 {
64 public:
65 // Types:
66 /// Definition of locale::category.
67 typedef int category;
68
69 // Forward decls and friends:
70 class facet;
71 class id;
72 class _Impl;
73
74 friend class facet;
75 friend class _Impl;
76
77 template<typename _Facet>
78 friend bool
79 has_facet(const locale&) throw();
80
81 template<typename _Facet>
82 friend const _Facet&
83 use_facet(const locale&);
84
85 template<typename _Facet>
86 friend const _Facet*
87 __try_use_facet(const locale&) _GLIBCXX_NOTHROW;
88
89 template<typename _Cache>
90 friend struct __use_cache;
91
92 ///@{
93 /**
94 * @brief Category values.
95 *
96 * The standard category values are none, ctype, numeric, collate, time,
97 * monetary, and messages. They form a bitmask that supports union and
98 * intersection. The category all is the union of these values.
99 *
100 * NB: Order must match _S_facet_categories definition in locale.cc
101 */
102 static const category none = 0;
103 static const category ctype = 1L << 0;
104 static const category numeric = 1L << 1;
105 static const category collate = 1L << 2;
106 static const category time = 1L << 3;
107 static const category monetary = 1L << 4;
108 static const category messages = 1L << 5;
109 static const category all = (ctype | numeric | collate |
110 time | monetary | messages);
111 ///@}
112
113 // Construct/copy/destroy:
114
115 /**
116 * @brief Default constructor.
117 *
118 * Constructs a copy of the global locale. If no locale has been
119 * explicitly set, this is the C locale.
120 */
121 locale() throw();
122
123 /**
124 * @brief Copy constructor.
125 *
126 * Constructs a copy of @a other.
127 *
128 * @param __other The locale to copy.
129 */
130 locale(const locale& __other) throw();
131
132 /**
133 * @brief Named locale constructor.
134 *
135 * Constructs a copy of the named C library locale.
136 *
137 * @param __s Name of the locale to construct.
138 * @throw std::runtime_error if __s is null or an undefined locale.
139 */
140 explicit
141 locale(const char* __s);
142
143 /**
144 * @brief Construct locale with facets from another locale.
145 *
146 * Constructs a copy of the locale @a base. The facets specified by @a
147 * cat are replaced with those from the locale named by @a s. If base is
148 * named, this locale instance will also be named.
149 *
150 * @param __base The locale to copy.
151 * @param __s Name of the locale to use facets from.
152 * @param __cat Set of categories defining the facets to use from __s.
153 * @throw std::runtime_error if __s is null or an undefined locale.
154 */
155 locale(const locale& __base, const char* __s, category __cat);
156
157 #if __cplusplus >= 201103L
158 /**
159 * @brief Named locale constructor.
160 *
161 * Constructs a copy of the named C library locale.
162 *
163 * @param __s Name of the locale to construct.
164 * @throw std::runtime_error if __s is an undefined locale.
165 */
166 explicit
167 locale(const std::string& __s) : locale(__s.c_str()) { }
168
169 /**
170 * @brief Construct locale with facets from another locale.
171 *
172 * Constructs a copy of the locale @a base. The facets specified by @a
173 * cat are replaced with those from the locale named by @a s. If base is
174 * named, this locale instance will also be named.
175 *
176 * @param __base The locale to copy.
177 * @param __s Name of the locale to use facets from.
178 * @param __cat Set of categories defining the facets to use from __s.
179 * @throw std::runtime_error if __s is an undefined locale.
180 */
181 locale(const locale& __base, const std::string& __s, category __cat)
182 : locale(__base, __s.c_str(), __cat) { }
183 #endif
184
185 /**
186 * @brief Construct locale with facets from another locale.
187 *
188 * Constructs a copy of the locale @a base. The facets specified by @a
189 * cat are replaced with those from the locale @a add. If @a base and @a
190 * add are named, this locale instance will also be named.
191 *
192 * @param __base The locale to copy.
193 * @param __add The locale to use facets from.
194 * @param __cat Set of categories defining the facets to use from add.
195 */
196 locale(const locale& __base, const locale& __add, category __cat);
197
198 /**
199 * @brief Construct locale with another facet.
200 *
201 * Constructs a copy of the locale @a __other. The facet @a __f
202 * is added to @a __other, replacing an existing facet of type
203 * Facet if there is one. If @a __f is null, this locale is a
204 * copy of @a __other.
205 *
206 * @param __other The locale to copy.
207 * @param __f The facet to add in.
208 */
209 template<typename _Facet>
210 locale(const locale& __other, _Facet* __f);
211
212 /// Locale destructor.
213 ~locale() throw();
214
215 /**
216 * @brief Assignment operator.
217 *
218 * Set this locale to be a copy of @a other.
219 *
220 * @param __other The locale to copy.
221 * @return A reference to this locale.
222 */
223 const locale&
224 operator=(const locale& __other) throw();
225
226 /**
227 * @brief Construct locale with another facet.
228 *
229 * Constructs and returns a new copy of this locale. Adds or replaces an
230 * existing facet of type Facet from the locale @a other into the new
231 * locale.
232 *
233 * @tparam _Facet The facet type to copy from other
234 * @param __other The locale to copy from.
235 * @return Newly constructed locale.
236 * @throw std::runtime_error if __other has no facet of type _Facet.
237 */
238 template<typename _Facet>
239 locale
240 combine(const locale& __other) const;
241
242 // Locale operations:
243 /**
244 * @brief Return locale name.
245 * @return Locale name or "*" if unnamed.
246 */
247 _GLIBCXX_DEFAULT_ABI_TAG
248 string
249 name() const;
250
251 /**
252 * @brief Locale equality.
253 *
254 * @param __other The locale to compare against.
255 * @return True if other and this refer to the same locale instance, are
256 * copies, or have the same name. False otherwise.
257 */
258 bool
259 operator==(const locale& __other) const throw();
260
261 #if __cpp_impl_three_way_comparison < 201907L
262 /**
263 * @brief Locale inequality.
264 *
265 * @param __other The locale to compare against.
266 * @return ! (*this == __other)
267 */
268 bool
269 operator!=(const locale& __other) const throw()
270 { return !(this->operator==(__other)); }
271 #endif
272
273 /**
274 * @brief Compare two strings according to collate.
275 *
276 * Template operator to compare two strings using the compare function of
277 * the collate facet in this locale. One use is to provide the locale to
278 * the sort function. For example, a vector v of strings could be sorted
279 * according to locale loc by doing:
280 * @code
281 * std::sort(v.begin(), v.end(), loc);
282 * @endcode
283 *
284 * @param __s1 First string to compare.
285 * @param __s2 Second string to compare.
286 * @return True if collate<_Char> facet compares __s1 < __s2, else false.
287 */
288 template<typename _Char, typename _Traits, typename _Alloc>
289 bool
290 operator()(const basic_string<_Char, _Traits, _Alloc>& __s1,
291 const basic_string<_Char, _Traits, _Alloc>& __s2) const;
292
293 // Global locale objects:
294 /**
295 * @brief Set global locale
296 *
297 * This function sets the global locale to the argument and returns a
298 * copy of the previous global locale. If the argument has a name, it
299 * will also call std::setlocale(LC_ALL, loc.name()).
300 *
301 * @param __loc The new locale to make global.
302 * @return Copy of the old global locale.
303 */
304 static locale
305 global(const locale& __loc);
306
307 /**
308 * @brief Return reference to the C locale.
309 */
310 static const locale&
311 classic();
312
313 private:
314 // The (shared) implementation
315 _Impl* _M_impl;
316
317 // The "C" reference locale
318 static _Impl* _S_classic;
319
320 // Current global locale
321 static _Impl* _S_global;
322
323 // Names of underlying locale categories.
324 // NB: locale::global() has to know how to modify all the
325 // underlying categories, not just the ones required by the C++
326 // standard.
327 static const char* const* const _S_categories;
328
329 // Number of standard categories. For C++, these categories are
330 // collate, ctype, monetary, numeric, time, and messages. These
331 // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE,
332 // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE
333 // 1003.1-2001) specifies LC_MESSAGES.
334 // In addition to the standard categories, the underlying
335 // operating system is allowed to define extra LC_*
336 // macros. For GNU systems, the following are also valid:
337 // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT,
338 // and LC_IDENTIFICATION.
339 enum { _S_categories_size = 6 + _GLIBCXX_NUM_CATEGORIES };
340
341 #ifdef __GTHREADS
342 static __gthread_once_t _S_once;
343 #endif
344
345 explicit
346 locale(_Impl*) throw();
347
348 static void
349 _S_initialize();
350
351 static void
352 _S_initialize_once() throw();
353
354 static category
355 _S_normalize_category(category);
356
357 void
358 _M_coalesce(const locale& __base, const locale& __add, category __cat);
359
360 #if _GLIBCXX_USE_CXX11_ABI
361 static const id* const _S_twinned_facets[];
362 #endif
363 };
364
365
366 // 22.1.1.1.2 Class locale::facet
367 /**
368 * @brief Localization functionality base class.
369 * @ingroup locales
370 *
371 * The facet class is the base class for a localization feature, such as
372 * money, time, and number printing. It provides common support for facets
373 * and reference management.
374 *
375 * Facets may not be copied or assigned.
376 */
377 class locale::facet
378 {
379 private:
380 friend class locale;
381 friend class locale::_Impl;
382
383 mutable _Atomic_word _M_refcount;
384
385 // Contains data from the underlying "C" library for the classic locale.
386 static __c_locale _S_c_locale;
387
388 // String literal for the name of the classic locale.
389 static const char _S_c_name[2];
390
391 #ifdef __GTHREADS
392 static __gthread_once_t _S_once;
393 #endif
394
395 static void
396 _S_initialize_once();
397
398 protected:
399 /**
400 * @brief Facet constructor.
401 *
402 * This is the constructor provided by the standard. If refs is 0, the
403 * facet is destroyed when the last referencing locale is destroyed.
404 * Otherwise the facet will never be destroyed.
405 *
406 * @param __refs The initial value for reference count.
407 */
408 explicit
409 facet(size_t __refs = 0) throw() : _M_refcount(__refs ? 1 : 0)
410 { }
411
412 /// Facet destructor.
413 virtual
414 ~facet();
415
416 static void
417 _S_create_c_locale(__c_locale& __cloc, const char* __s,
418 __c_locale __old = 0);
419
420 static __c_locale
421 _S_clone_c_locale(__c_locale& __cloc) throw();
422
423 static void
424 _S_destroy_c_locale(__c_locale& __cloc);
425
426 static __c_locale
427 _S_lc_ctype_c_locale(__c_locale __cloc, const char* __s);
428
429 // Returns data from the underlying "C" library data for the
430 // classic locale.
431 static __c_locale
432 _S_get_c_locale();
433
434 _GLIBCXX_CONST static const char*
435 _S_get_c_name() throw();
436
437 #if __cplusplus < 201103L
438 private:
439 facet(const facet&); // Not defined.
440
441 facet&
442 operator=(const facet&); // Not defined.
443 #else
444 facet(const facet&) = delete;
445
446 facet&
447 operator=(const facet&) = delete;
448 #endif
449
450 private:
451 void
452 _M_add_reference() const throw()
453 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
454
455 void
456 _M_remove_reference() const throw()
457 {
458 // Be race-detector-friendly. For more info see bits/c++config.
459 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
460 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1)
461 {
462 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
463 __try
464 { delete this; }
465 __catch(...)
466 { }
467 }
468 }
469
470 const facet* _M_sso_shim(const id*) const;
471 const facet* _M_cow_shim(const id*) const;
472
473 protected:
474 class __shim; // For internal use only.
475 };
476
477
478 // 22.1.1.1.3 Class locale::id
479 /**
480 * @brief Facet ID class.
481 * @ingroup locales
482 *
483 * The ID class provides facets with an index used to identify them.
484 * Every facet class must define a public static member locale::id, or be
485 * derived from a facet that provides this member, otherwise the facet
486 * cannot be used in a locale. The locale::id ensures that each class
487 * type gets a unique identifier.
488 */
489 class locale::id
490 {
491 private:
492 friend class locale;
493 friend class locale::_Impl;
494
495 template<typename _Facet>
496 friend const _Facet&
497 use_facet(const locale&);
498
499 template<typename _Facet>
500 friend bool
501 has_facet(const locale&) throw();
502
503 template<typename _Facet>
504 friend const _Facet*
505 __try_use_facet(const locale&) _GLIBCXX_NOTHROW;
506
507 // NB: There is no accessor for _M_index because it may be used
508 // before the constructor is run; the effect of calling a member
509 // function (even an inline) would be undefined.
510 mutable size_t _M_index;
511
512 // Last id number assigned.
513 static _Atomic_word _S_refcount;
514
515 void
516 operator=(const id&); // Not defined.
517
518 id(const id&); // Not defined.
519
520 public:
521 // NB: This class is always a static data member, and thus can be
522 // counted on to be zero-initialized.
523 /// Constructor.
524 id() { }
525
526 size_t
527 _M_id() const throw();
528 };
529
530
531 // Implementation object for locale.
532 class locale::_Impl
533 {
534 public:
535 // Friends.
536 friend class locale;
537 friend class locale::facet;
538
539 template<typename _Facet>
540 friend bool
541 has_facet(const locale&) throw();
542
543 template<typename _Facet>
544 friend const _Facet&
545 use_facet(const locale&);
546
547 template<typename _Facet>
548 friend const _Facet*
549 __try_use_facet(const locale&) _GLIBCXX_NOTHROW;
550
551 template<typename _Cache>
552 friend struct __use_cache;
553
554 private:
555 // Data Members.
556 _Atomic_word _M_refcount;
557 const facet** _M_facets;
558 size_t _M_facets_size;
559 const facet** _M_caches;
560 char** _M_names;
561 static const locale::id* const _S_id_ctype[];
562 static const locale::id* const _S_id_numeric[];
563 static const locale::id* const _S_id_collate[];
564 static const locale::id* const _S_id_time[];
565 static const locale::id* const _S_id_monetary[];
566 static const locale::id* const _S_id_messages[];
567 static const locale::id* const* const _S_facet_categories[];
568
569 void
570 _M_add_reference() throw()
571 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
572
573 void
574 _M_remove_reference() throw()
575 {
576 // Be race-detector-friendly. For more info see bits/c++config.
577 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
578 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1)
579 {
580 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
581 __try
582 { delete this; }
583 __catch(...)
584 { }
585 }
586 }
587
588 _Impl(const _Impl&, size_t);
589 _Impl(const char*, size_t);
590 _Impl(size_t) throw();
591
592 ~_Impl() throw();
593
594 _Impl(const _Impl&); // Not defined.
595
596 void
597 operator=(const _Impl&); // Not defined.
598
599 bool
600 _M_check_same_name()
601 {
602 bool __ret = true;
603 if (_M_names[1])
604 // We must actually compare all the _M_names: can be all equal!
605 for (size_t __i = 0; __ret && __i < _S_categories_size - 1; ++__i)
606 __ret = __builtin_strcmp(_M_names[__i], _M_names[__i + 1]) == 0;
607 return __ret;
608 }
609
610 void
611 _M_replace_categories(const _Impl*, category);
612
613 void
614 _M_replace_category(const _Impl*, const locale::id* const*);
615
616 void
617 _M_replace_facet(const _Impl*, const locale::id*);
618
619 void
620 _M_install_facet(const locale::id*, const facet*);
621
622 template<typename _Facet>
623 void
624 _M_init_facet(_Facet* __facet)
625 { _M_install_facet(&_Facet::id, __facet); }
626
627 template<typename _Facet>
628 void
629 _M_init_facet_unchecked(_Facet* __facet)
630 {
631 __facet->_M_add_reference();
632 _M_facets[_Facet::id._M_id()] = __facet;
633 }
634
635 void
636 _M_install_cache(const facet*, size_t);
637
638 void _M_init_extra(facet**);
639 void _M_init_extra(void*, void*, const char*, const char*);
640
641 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
642 void _M_init_extra_ldbl128(bool);
643 #endif
644 };
645
646
647 /**
648 * @brief Facet for localized string comparison.
649 *
650 * This facet encapsulates the code to compare strings in a localized
651 * manner.
652 *
653 * The collate template uses protected virtual functions to provide
654 * the actual results. The public accessors forward the call to
655 * the virtual functions. These virtual functions are hooks for
656 * developers to implement the behavior they require from the
657 * collate facet.
658 */
659 template<typename _CharT>
660 class _GLIBCXX_NAMESPACE_CXX11 collate : public locale::facet
661 {
662 public:
663 // Types:
664 ///@{
665 /// Public typedefs
666 typedef _CharT char_type;
667 typedef basic_string<_CharT> string_type;
668 ///@}
669
670 protected:
671 // Underlying "C" library locale information saved from
672 // initialization, needed by collate_byname as well.
673 __c_locale _M_c_locale_collate;
674
675 public:
676 /// Numpunct facet id.
677 static locale::id id;
678
679 /**
680 * @brief Constructor performs initialization.
681 *
682 * This is the constructor provided by the standard.
683 *
684 * @param __refs Passed to the base facet class.
685 */
686 explicit
687 collate(size_t __refs = 0)
688 : facet(__refs), _M_c_locale_collate(_S_get_c_locale())
689 { }
690
691 /**
692 * @brief Internal constructor. Not for general use.
693 *
694 * This is a constructor for use by the library itself to set up new
695 * locales.
696 *
697 * @param __cloc The C locale.
698 * @param __refs Passed to the base facet class.
699 */
700 explicit
701 collate(__c_locale __cloc, size_t __refs = 0)
702 : facet(__refs), _M_c_locale_collate(_S_clone_c_locale(__cloc))
703 { }
704
705 /**
706 * @brief Compare two strings.
707 *
708 * This function compares two strings and returns the result by calling
709 * collate::do_compare().
710 *
711 * @param __lo1 Start of string 1.
712 * @param __hi1 End of string 1.
713 * @param __lo2 Start of string 2.
714 * @param __hi2 End of string 2.
715 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
716 */
717 int
718 compare(const _CharT* __lo1, const _CharT* __hi1,
719 const _CharT* __lo2, const _CharT* __hi2) const
720 { return this->do_compare(__lo1, __hi1, __lo2, __hi2); }
721
722 /**
723 * @brief Transform string to comparable form.
724 *
725 * This function is a wrapper for strxfrm functionality. It takes the
726 * input string and returns a modified string that can be directly
727 * compared to other transformed strings. In the C locale, this
728 * function just returns a copy of the input string. In some other
729 * locales, it may replace two chars with one, change a char for
730 * another, etc. It does so by returning collate::do_transform().
731 *
732 * @param __lo Start of string.
733 * @param __hi End of string.
734 * @return Transformed string_type.
735 */
736 string_type
737 transform(const _CharT* __lo, const _CharT* __hi) const
738 { return this->do_transform(__lo, __hi); }
739
740 /**
741 * @brief Return hash of a string.
742 *
743 * This function computes and returns a hash on the input string. It
744 * does so by returning collate::do_hash().
745 *
746 * @param __lo Start of string.
747 * @param __hi End of string.
748 * @return Hash value.
749 */
750 long
751 hash(const _CharT* __lo, const _CharT* __hi) const
752 { return this->do_hash(__lo, __hi); }
753
754 // Used to abstract out _CharT bits in virtual member functions, below.
755 int
756 _M_compare(const _CharT*, const _CharT*) const throw();
757
758 size_t
759 _M_transform(_CharT*, const _CharT*, size_t) const throw();
760
761 protected:
762 /// Destructor.
763 virtual
764 ~collate()
765 { _S_destroy_c_locale(_M_c_locale_collate); }
766
767 /**
768 * @brief Compare two strings.
769 *
770 * This function is a hook for derived classes to change the value
771 * returned. @see compare().
772 *
773 * @param __lo1 Start of string 1.
774 * @param __hi1 End of string 1.
775 * @param __lo2 Start of string 2.
776 * @param __hi2 End of string 2.
777 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
778 */
779 virtual int
780 do_compare(const _CharT* __lo1, const _CharT* __hi1,
781 const _CharT* __lo2, const _CharT* __hi2) const;
782
783 /**
784 * @brief Transform string to comparable form.
785 *
786 * This function is a hook for derived classes to change the value
787 * returned.
788 *
789 * @param __lo Start.
790 * @param __hi End.
791 * @return transformed string.
792 */
793 virtual string_type
794 do_transform(const _CharT* __lo, const _CharT* __hi) const;
795
796 /**
797 * @brief Return hash of a string.
798 *
799 * This function computes and returns a hash on the input string. This
800 * function is a hook for derived classes to change the value returned.
801 *
802 * @param __lo Start of string.
803 * @param __hi End of string.
804 * @return Hash value.
805 */
806 virtual long
807 do_hash(const _CharT* __lo, const _CharT* __hi) const;
808 };
809
810 template<typename _CharT>
811 locale::id collate<_CharT>::id;
812
813 // Specializations.
814 template<>
815 int
816 collate<char>::_M_compare(const char*, const char*) const throw();
817
818 template<>
819 size_t
820 collate<char>::_M_transform(char*, const char*, size_t) const throw();
821
822 #ifdef _GLIBCXX_USE_WCHAR_T
823 template<>
824 int
825 collate<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw();
826
827 template<>
828 size_t
829 collate<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw();
830 #endif
831
832 /// class collate_byname [22.2.4.2].
833 template<typename _CharT>
834 class _GLIBCXX_NAMESPACE_CXX11 collate_byname : public collate<_CharT>
835 {
836 public:
837 ///@{
838 /// Public typedefs
839 typedef _CharT char_type;
840 typedef basic_string<_CharT> string_type;
841 ///@}
842
843 explicit
844 collate_byname(const char* __s, size_t __refs = 0)
845 : collate<_CharT>(__refs)
846 {
847 if (__builtin_strcmp(__s, "C") != 0
848 && __builtin_strcmp(__s, "POSIX") != 0)
849 {
850 this->_S_destroy_c_locale(this->_M_c_locale_collate);
851 this->_S_create_c_locale(this->_M_c_locale_collate, __s);
852 }
853 }
854
855 #if __cplusplus >= 201103L
856 explicit
857 collate_byname(const string& __s, size_t __refs = 0)
858 : collate_byname(__s.c_str(), __refs) { }
859 #endif
860
861 protected:
862 virtual
863 ~collate_byname() { }
864 };
865
866 _GLIBCXX_END_NAMESPACE_VERSION
867 } // namespace
868
869 # include <bits/locale_classes.tcc>
870
871 #endif