libstdc++
char_traits.h
Go to the documentation of this file.
1 // Character Traits for use by standard string and iostream -*- C++ -*-
2 
3 // Copyright (C) 1997-2017 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/char_traits.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{string}
28  */
29 
30 //
31 // ISO C++ 14882: 21 Strings library
32 //
33 
34 #ifndef _CHAR_TRAITS_H
35 #define _CHAR_TRAITS_H 1
36 
37 #pragma GCC system_header
38 
39 #include <bits/stl_algobase.h> // std::copy, std::fill_n
40 #include <bits/postypes.h> // For streampos
41 #include <cwchar> // For WEOF, wmemmove, wmemset, etc.
42 
43 #ifndef _GLIBCXX_ALWAYS_INLINE
44 #define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__))
45 #endif
46 
47 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
48 {
49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 
51  /**
52  * @brief Mapping from character type to associated types.
53  *
54  * @note This is an implementation class for the generic version
55  * of char_traits. It defines int_type, off_type, pos_type, and
56  * state_type. By default these are unsigned long, streamoff,
57  * streampos, and mbstate_t. Users who need a different set of
58  * types, but who don't need to change the definitions of any function
59  * defined in char_traits, can specialize __gnu_cxx::_Char_types
60  * while leaving __gnu_cxx::char_traits alone. */
61  template<typename _CharT>
62  struct _Char_types
63  {
64  typedef unsigned long int_type;
65  typedef std::streampos pos_type;
66  typedef std::streamoff off_type;
67  typedef std::mbstate_t state_type;
68  };
69 
70 
71  /**
72  * @brief Base class used to implement std::char_traits.
73  *
74  * @note For any given actual character type, this definition is
75  * probably wrong. (Most of the member functions are likely to be
76  * right, but the int_type and state_type typedefs, and the eof()
77  * member function, are likely to be wrong.) The reason this class
78  * exists is so users can specialize it. Classes in namespace std
79  * may not be specialized for fundamental types, but classes in
80  * namespace __gnu_cxx may be.
81  *
82  * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
83  * for advice on how to make use of this class for @a unusual character
84  * types. Also, check out include/ext/pod_char_traits.h.
85  */
86  template<typename _CharT>
87  struct char_traits
88  {
89  typedef _CharT char_type;
90  typedef typename _Char_types<_CharT>::int_type int_type;
91  typedef typename _Char_types<_CharT>::pos_type pos_type;
92  typedef typename _Char_types<_CharT>::off_type off_type;
93  typedef typename _Char_types<_CharT>::state_type state_type;
94 
95  static _GLIBCXX14_CONSTEXPR void
96  assign(char_type& __c1, const char_type& __c2)
97  { __c1 = __c2; }
98 
99  static _GLIBCXX_CONSTEXPR bool
100  eq(const char_type& __c1, const char_type& __c2)
101  { return __c1 == __c2; }
102 
103  static _GLIBCXX_CONSTEXPR bool
104  lt(const char_type& __c1, const char_type& __c2)
105  { return __c1 < __c2; }
106 
107  static _GLIBCXX14_CONSTEXPR int
108  compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
109 
110  static _GLIBCXX14_CONSTEXPR std::size_t
111  length(const char_type* __s);
112 
113  static _GLIBCXX14_CONSTEXPR const char_type*
114  find(const char_type* __s, std::size_t __n, const char_type& __a);
115 
116  static char_type*
117  move(char_type* __s1, const char_type* __s2, std::size_t __n);
118 
119  static char_type*
120  copy(char_type* __s1, const char_type* __s2, std::size_t __n);
121 
122  static char_type*
123  assign(char_type* __s, std::size_t __n, char_type __a);
124 
125  static _GLIBCXX_CONSTEXPR char_type
126  to_char_type(const int_type& __c)
127  { return static_cast<char_type>(__c); }
128 
129  static _GLIBCXX_CONSTEXPR int_type
130  to_int_type(const char_type& __c)
131  { return static_cast<int_type>(__c); }
132 
133  static _GLIBCXX_CONSTEXPR bool
134  eq_int_type(const int_type& __c1, const int_type& __c2)
135  { return __c1 == __c2; }
136 
137  static _GLIBCXX_CONSTEXPR int_type
138  eof()
139  { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
140 
141  static _GLIBCXX_CONSTEXPR int_type
142  not_eof(const int_type& __c)
143  { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); }
144  };
145 
146 #define __cpp_lib_constexpr_char_traits 201611
147 
148  template<typename _CharT>
149  _GLIBCXX14_CONSTEXPR int
151  compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
152  {
153  for (std::size_t __i = 0; __i < __n; ++__i)
154  if (lt(__s1[__i], __s2[__i]))
155  return -1;
156  else if (lt(__s2[__i], __s1[__i]))
157  return 1;
158  return 0;
159  }
160 
161  template<typename _CharT>
162  _GLIBCXX14_CONSTEXPR std::size_t
164  length(const char_type* __p)
165  {
166  std::size_t __i = 0;
167  while (!eq(__p[__i], char_type()))
168  ++__i;
169  return __i;
170  }
171 
172  template<typename _CharT>
173  _GLIBCXX14_CONSTEXPR const typename char_traits<_CharT>::char_type*
175  find(const char_type* __s, std::size_t __n, const char_type& __a)
176  {
177  for (std::size_t __i = 0; __i < __n; ++__i)
178  if (eq(__s[__i], __a))
179  return __s + __i;
180  return 0;
181  }
182 
183  template<typename _CharT>
184  typename char_traits<_CharT>::char_type*
186  move(char_type* __s1, const char_type* __s2, std::size_t __n)
187  {
188  return static_cast<_CharT*>(__builtin_memmove(__s1, __s2,
189  __n * sizeof(char_type)));
190  }
191 
192  template<typename _CharT>
193  typename char_traits<_CharT>::char_type*
195  copy(char_type* __s1, const char_type* __s2, std::size_t __n)
196  {
197  // NB: Inline std::copy so no recursive dependencies.
198  std::copy(__s2, __s2 + __n, __s1);
199  return __s1;
200  }
201 
202  template<typename _CharT>
203  typename char_traits<_CharT>::char_type*
205  assign(char_type* __s, std::size_t __n, char_type __a)
206  {
207  // NB: Inline std::fill_n so no recursive dependencies.
208  std::fill_n(__s, __n, __a);
209  return __s;
210  }
211 
212 _GLIBCXX_END_NAMESPACE_VERSION
213 } // namespace
214 
215 namespace std _GLIBCXX_VISIBILITY(default)
216 {
217 _GLIBCXX_BEGIN_NAMESPACE_VERSION
218 
219 #if __cplusplus > 201402
220  /**
221  * @brief Determine whether the characters of a NULL-terminated
222  * string are known at compile time.
223  * @param __s The string.
224  *
225  * Assumes that _CharT is a built-in character type.
226  */
227  template<typename _CharT>
228  static _GLIBCXX_ALWAYS_INLINE constexpr bool
229  __constant_string_p(const _CharT* __s)
230  {
231  while (__builtin_constant_p(*__s) && *__s)
232  __s++;
233  return __builtin_constant_p(*__s);
234  }
235 
236  /**
237  * @brief Determine whether the characters of a character array are
238  * known at compile time.
239  * @param __a The character array.
240  * @param __n Number of characters.
241  *
242  * Assumes that _CharT is a built-in character type.
243  */
244  template<typename _CharT>
245  static _GLIBCXX_ALWAYS_INLINE constexpr bool
246  __constant_char_array_p(const _CharT* __a, size_t __n)
247  {
248  size_t __i = 0;
249  while (__builtin_constant_p(__a[__i]) && __i < __n)
250  __i++;
251  return __i == __n;
252  }
253 #endif
254 
255  // 21.1
256  /**
257  * @brief Basis for explicit traits specializations.
258  *
259  * @note For any given actual character type, this definition is
260  * probably wrong. Since this is just a thin wrapper around
261  * __gnu_cxx::char_traits, it is possible to achieve a more
262  * appropriate definition by specializing __gnu_cxx::char_traits.
263  *
264  * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
265  * for advice on how to make use of this class for @a unusual character
266  * types. Also, check out include/ext/pod_char_traits.h.
267  */
268  template<class _CharT>
269  struct char_traits : public __gnu_cxx::char_traits<_CharT>
270  { };
271 
272 
273  /// 21.1.3.1 char_traits specializations
274  template<>
275  struct char_traits<char>
276  {
277  typedef char char_type;
278  typedef int int_type;
279  typedef streampos pos_type;
280  typedef streamoff off_type;
281  typedef mbstate_t state_type;
282 
283  static _GLIBCXX17_CONSTEXPR void
284  assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
285  { __c1 = __c2; }
286 
287  static _GLIBCXX_CONSTEXPR bool
288  eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
289  { return __c1 == __c2; }
290 
291  static _GLIBCXX_CONSTEXPR bool
292  lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
293  {
294  // LWG 467.
295  return (static_cast<unsigned char>(__c1)
296  < static_cast<unsigned char>(__c2));
297  }
298 
299  static _GLIBCXX17_CONSTEXPR int
300  compare(const char_type* __s1, const char_type* __s2, size_t __n)
301  {
302 #if __cplusplus > 201402
303  if (__builtin_constant_p(__n)
304  && __constant_char_array_p(__s1, __n)
305  && __constant_char_array_p(__s2, __n))
306  return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n);
307 #endif
308  if (__n == 0)
309  return 0;
310  return __builtin_memcmp(__s1, __s2, __n);
311  }
312 
313  static _GLIBCXX17_CONSTEXPR size_t
314  length(const char_type* __s)
315  {
316 #if __cplusplus > 201402
317  if (__constant_string_p(__s))
319 #endif
320  return __builtin_strlen(__s);
321  }
322 
323  static _GLIBCXX17_CONSTEXPR const char_type*
324  find(const char_type* __s, size_t __n, const char_type& __a)
325  {
326 #if __cplusplus > 201402
327  if (__builtin_constant_p(__n)
328  && __builtin_constant_p(__a)
329  && __constant_char_array_p(__s, __n))
330  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
331 #endif
332  if (__n == 0)
333  return 0;
334  return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n));
335  }
336 
337  static char_type*
338  move(char_type* __s1, const char_type* __s2, size_t __n)
339  {
340  if (__n == 0)
341  return __s1;
342  return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n));
343  }
344 
345  static char_type*
346  copy(char_type* __s1, const char_type* __s2, size_t __n)
347  {
348  if (__n == 0)
349  return __s1;
350  return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
351  }
352 
353  static char_type*
354  assign(char_type* __s, size_t __n, char_type __a)
355  {
356  if (__n == 0)
357  return __s;
358  return static_cast<char_type*>(__builtin_memset(__s, __a, __n));
359  }
360 
361  static _GLIBCXX_CONSTEXPR char_type
362  to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
363  { return static_cast<char_type>(__c); }
364 
365  // To keep both the byte 0xff and the eof symbol 0xffffffff
366  // from ending up as 0xffffffff.
367  static _GLIBCXX_CONSTEXPR int_type
368  to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
369  { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
370 
371  static _GLIBCXX_CONSTEXPR bool
372  eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
373  { return __c1 == __c2; }
374 
375  static _GLIBCXX_CONSTEXPR int_type
376  eof() _GLIBCXX_NOEXCEPT
377  { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
378 
379  static _GLIBCXX_CONSTEXPR int_type
380  not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
381  { return (__c == eof()) ? 0 : __c; }
382  };
383 
384 
385 #ifdef _GLIBCXX_USE_WCHAR_T
386  /// 21.1.3.2 char_traits specializations
387  template<>
388  struct char_traits<wchar_t>
389  {
390  typedef wchar_t char_type;
391  typedef wint_t int_type;
392  typedef streamoff off_type;
393  typedef wstreampos pos_type;
394  typedef mbstate_t state_type;
395 
396  static _GLIBCXX17_CONSTEXPR void
397  assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
398  { __c1 = __c2; }
399 
400  static _GLIBCXX_CONSTEXPR bool
401  eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
402  { return __c1 == __c2; }
403 
404  static _GLIBCXX_CONSTEXPR bool
405  lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
406  { return __c1 < __c2; }
407 
408  static _GLIBCXX17_CONSTEXPR int
409  compare(const char_type* __s1, const char_type* __s2, size_t __n)
410  {
411 #if __cplusplus > 201402
412  if (__builtin_constant_p(__n)
413  && __constant_char_array_p(__s1, __n)
414  && __constant_char_array_p(__s2, __n))
415  return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n);
416 #endif
417  if (__n == 0)
418  return 0;
419  else
420  return wmemcmp(__s1, __s2, __n);
421  }
422 
423  static _GLIBCXX17_CONSTEXPR size_t
424  length(const char_type* __s)
425  {
426 #if __cplusplus > 201402
427  if (__constant_string_p(__s))
429  else
430 #endif
431  return wcslen(__s);
432  }
433 
434  static _GLIBCXX17_CONSTEXPR const char_type*
435  find(const char_type* __s, size_t __n, const char_type& __a)
436  {
437 #if __cplusplus > 201402
438  if (__builtin_constant_p(__n)
439  && __builtin_constant_p(__a)
440  && __constant_char_array_p(__s, __n))
441  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
442 #endif
443  if (__n == 0)
444  return 0;
445  else
446  return wmemchr(__s, __a, __n);
447  }
448 
449  static char_type*
450  move(char_type* __s1, const char_type* __s2, size_t __n)
451  {
452  if (__n == 0)
453  return __s1;
454  return wmemmove(__s1, __s2, __n);
455  }
456 
457  static char_type*
458  copy(char_type* __s1, const char_type* __s2, size_t __n)
459  {
460  if (__n == 0)
461  return __s1;
462  return wmemcpy(__s1, __s2, __n);
463  }
464 
465  static char_type*
466  assign(char_type* __s, size_t __n, char_type __a)
467  {
468  if (__n == 0)
469  return __s;
470  return wmemset(__s, __a, __n);
471  }
472 
473  static _GLIBCXX_CONSTEXPR char_type
474  to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
475  { return char_type(__c); }
476 
477  static _GLIBCXX_CONSTEXPR int_type
478  to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
479  { return int_type(__c); }
480 
481  static _GLIBCXX_CONSTEXPR bool
482  eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
483  { return __c1 == __c2; }
484 
485  static _GLIBCXX_CONSTEXPR int_type
486  eof() _GLIBCXX_NOEXCEPT
487  { return static_cast<int_type>(WEOF); }
488 
489  static _GLIBCXX_CONSTEXPR int_type
490  not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
491  { return eq_int_type(__c, eof()) ? 0 : __c; }
492  };
493 #endif //_GLIBCXX_USE_WCHAR_T
494 
495 _GLIBCXX_END_NAMESPACE_VERSION
496 } // namespace
497 
498 #if ((__cplusplus >= 201103L) \
499  && defined(_GLIBCXX_USE_C99_STDINT_TR1))
500 
501 #include <cstdint>
502 
503 namespace std _GLIBCXX_VISIBILITY(default)
504 {
505 _GLIBCXX_BEGIN_NAMESPACE_VERSION
506 
507  template<>
508  struct char_traits<char16_t>
509  {
510  typedef char16_t char_type;
511  typedef uint_least16_t int_type;
512  typedef streamoff off_type;
513  typedef u16streampos pos_type;
514  typedef mbstate_t state_type;
515 
516  static _GLIBCXX17_CONSTEXPR void
517  assign(char_type& __c1, const char_type& __c2) noexcept
518  { __c1 = __c2; }
519 
520  static constexpr bool
521  eq(const char_type& __c1, const char_type& __c2) noexcept
522  { return __c1 == __c2; }
523 
524  static constexpr bool
525  lt(const char_type& __c1, const char_type& __c2) noexcept
526  { return __c1 < __c2; }
527 
528  static _GLIBCXX17_CONSTEXPR int
529  compare(const char_type* __s1, const char_type* __s2, size_t __n)
530  {
531  for (size_t __i = 0; __i < __n; ++__i)
532  if (lt(__s1[__i], __s2[__i]))
533  return -1;
534  else if (lt(__s2[__i], __s1[__i]))
535  return 1;
536  return 0;
537  }
538 
539  static _GLIBCXX17_CONSTEXPR size_t
540  length(const char_type* __s)
541  {
542  size_t __i = 0;
543  while (!eq(__s[__i], char_type()))
544  ++__i;
545  return __i;
546  }
547 
548  static _GLIBCXX17_CONSTEXPR const char_type*
549  find(const char_type* __s, size_t __n, const char_type& __a)
550  {
551  for (size_t __i = 0; __i < __n; ++__i)
552  if (eq(__s[__i], __a))
553  return __s + __i;
554  return 0;
555  }
556 
557  static char_type*
558  move(char_type* __s1, const char_type* __s2, size_t __n)
559  {
560  if (__n == 0)
561  return __s1;
562  return (static_cast<char_type*>
563  (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
564  }
565 
566  static char_type*
567  copy(char_type* __s1, const char_type* __s2, size_t __n)
568  {
569  if (__n == 0)
570  return __s1;
571  return (static_cast<char_type*>
572  (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
573  }
574 
575  static char_type*
576  assign(char_type* __s, size_t __n, char_type __a)
577  {
578  for (size_t __i = 0; __i < __n; ++__i)
579  assign(__s[__i], __a);
580  return __s;
581  }
582 
583  static constexpr char_type
584  to_char_type(const int_type& __c) noexcept
585  { return char_type(__c); }
586 
587  static constexpr int_type
588  to_int_type(const char_type& __c) noexcept
589  { return int_type(__c); }
590 
591  static constexpr bool
592  eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
593  { return __c1 == __c2; }
594 
595  static constexpr int_type
596  eof() noexcept
597  { return static_cast<int_type>(-1); }
598 
599  static constexpr int_type
600  not_eof(const int_type& __c) noexcept
601  { return eq_int_type(__c, eof()) ? 0 : __c; }
602  };
603 
604  template<>
605  struct char_traits<char32_t>
606  {
607  typedef char32_t char_type;
608  typedef uint_least32_t int_type;
609  typedef streamoff off_type;
610  typedef u32streampos pos_type;
611  typedef mbstate_t state_type;
612 
613  static _GLIBCXX17_CONSTEXPR void
614  assign(char_type& __c1, const char_type& __c2) noexcept
615  { __c1 = __c2; }
616 
617  static constexpr bool
618  eq(const char_type& __c1, const char_type& __c2) noexcept
619  { return __c1 == __c2; }
620 
621  static constexpr bool
622  lt(const char_type& __c1, const char_type& __c2) noexcept
623  { return __c1 < __c2; }
624 
625  static _GLIBCXX17_CONSTEXPR int
626  compare(const char_type* __s1, const char_type* __s2, size_t __n)
627  {
628  for (size_t __i = 0; __i < __n; ++__i)
629  if (lt(__s1[__i], __s2[__i]))
630  return -1;
631  else if (lt(__s2[__i], __s1[__i]))
632  return 1;
633  return 0;
634  }
635 
636  static _GLIBCXX17_CONSTEXPR size_t
637  length(const char_type* __s)
638  {
639  size_t __i = 0;
640  while (!eq(__s[__i], char_type()))
641  ++__i;
642  return __i;
643  }
644 
645  static _GLIBCXX17_CONSTEXPR const char_type*
646  find(const char_type* __s, size_t __n, const char_type& __a)
647  {
648  for (size_t __i = 0; __i < __n; ++__i)
649  if (eq(__s[__i], __a))
650  return __s + __i;
651  return 0;
652  }
653 
654  static char_type*
655  move(char_type* __s1, const char_type* __s2, size_t __n)
656  {
657  if (__n == 0)
658  return __s1;
659  return (static_cast<char_type*>
660  (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
661  }
662 
663  static char_type*
664  copy(char_type* __s1, const char_type* __s2, size_t __n)
665  {
666  if (__n == 0)
667  return __s1;
668  return (static_cast<char_type*>
669  (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
670  }
671 
672  static char_type*
673  assign(char_type* __s, size_t __n, char_type __a)
674  {
675  for (size_t __i = 0; __i < __n; ++__i)
676  assign(__s[__i], __a);
677  return __s;
678  }
679 
680  static constexpr char_type
681  to_char_type(const int_type& __c) noexcept
682  { return char_type(__c); }
683 
684  static constexpr int_type
685  to_int_type(const char_type& __c) noexcept
686  { return int_type(__c); }
687 
688  static constexpr bool
689  eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
690  { return __c1 == __c2; }
691 
692  static constexpr int_type
693  eof() noexcept
694  { return static_cast<int_type>(-1); }
695 
696  static constexpr int_type
697  not_eof(const int_type& __c) noexcept
698  { return eq_int_type(__c, eof()) ? 0 : __c; }
699  };
700 
701 _GLIBCXX_END_NAMESPACE_VERSION
702 } // namespace
703 
704 #endif
705 
706 #endif // _CHAR_TRAITS_H
Base class used to implement std::char_traits.
Definition: char_traits.h:87
ISO C++ entities toplevel namespace is std.
GNU extensions for public use.
Mapping from character type to associated types.
Definition: char_traits.h:62
Class representing stream positions.
Definition: postypes.h:112
Basis for explicit traits specializations.
Definition: char_traits.h:269
long long streamoff
Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
Definition: postypes.h:94