libstdc++
ios_base.h
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1 // Iostreams base classes -*- C++ -*-
2 
3 // Copyright (C) 1997-2024 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/ios_base.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{ios}
28  */
29 
30 //
31 // ISO C++ 14882: 27.4 Iostreams base classes
32 //
33 
34 #ifndef _IOS_BASE_H
35 #define _IOS_BASE_H 1
36 
37 #pragma GCC system_header
38 
39 #include <ext/atomicity.h>
40 #include <bits/localefwd.h>
41 #include <bits/locale_classes.h>
42 
43 #if __cplusplus < 201103L
44 # include <stdexcept>
45 #else
46 # include <system_error>
47 #endif
48 
49 namespace std _GLIBCXX_VISIBILITY(default)
50 {
51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
52 
53  // The following definitions of bitmask types are enums, not ints,
54  // as permitted (but not required) in the standard, in order to provide
55  // better type safety in iostream calls. A side effect is that in C++98
56  // expressions involving them are not compile-time constants.
57  enum _Ios_Fmtflags
58  {
59  _S_boolalpha = 1L << 0,
60  _S_dec = 1L << 1,
61  _S_fixed = 1L << 2,
62  _S_hex = 1L << 3,
63  _S_internal = 1L << 4,
64  _S_left = 1L << 5,
65  _S_oct = 1L << 6,
66  _S_right = 1L << 7,
67  _S_scientific = 1L << 8,
68  _S_showbase = 1L << 9,
69  _S_showpoint = 1L << 10,
70  _S_showpos = 1L << 11,
71  _S_skipws = 1L << 12,
72  _S_unitbuf = 1L << 13,
73  _S_uppercase = 1L << 14,
74  _S_adjustfield = _S_left | _S_right | _S_internal,
75  _S_basefield = _S_dec | _S_oct | _S_hex,
76  _S_floatfield = _S_scientific | _S_fixed,
77  _S_ios_fmtflags_end = 1L << 16,
78  _S_ios_fmtflags_max = __INT_MAX__,
79  _S_ios_fmtflags_min = ~__INT_MAX__
80  };
81 
82  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
83  inline _Ios_Fmtflags
84  operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
85  { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }
86 
87  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
88  inline _Ios_Fmtflags
89  operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
90  { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }
91 
92  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
93  inline _Ios_Fmtflags
94  operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
95  { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }
96 
97  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
98  inline _Ios_Fmtflags
99  operator~(_Ios_Fmtflags __a) _GLIBCXX_NOTHROW
100  { return _Ios_Fmtflags(~static_cast<int>(__a)); }
101 
102  _GLIBCXX14_CONSTEXPR
103  inline const _Ios_Fmtflags&
104  operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
105  { return __a = __a | __b; }
106 
107  _GLIBCXX14_CONSTEXPR
108  inline const _Ios_Fmtflags&
109  operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
110  { return __a = __a & __b; }
111 
112  _GLIBCXX14_CONSTEXPR
113  inline const _Ios_Fmtflags&
114  operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
115  { return __a = __a ^ __b; }
116 
117 
118  enum _Ios_Openmode
119  {
120  _S_app = 1L << 0,
121  _S_ate = 1L << 1,
122  _S_bin = 1L << 2,
123  _S_in = 1L << 3,
124  _S_out = 1L << 4,
125  _S_trunc = 1L << 5,
126  _S_noreplace = 1L << 6,
127  _S_ios_openmode_end = 1L << 16,
128  _S_ios_openmode_max = __INT_MAX__,
129  _S_ios_openmode_min = ~__INT_MAX__
130  };
131 
132  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
133  inline _Ios_Openmode
134  operator&(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
135  { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }
136 
137  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
138  inline _Ios_Openmode
139  operator|(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
140  { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }
141 
142  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
143  inline _Ios_Openmode
144  operator^(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
145  { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }
146 
147  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
148  inline _Ios_Openmode
149  operator~(_Ios_Openmode __a) _GLIBCXX_NOTHROW
150  { return _Ios_Openmode(~static_cast<int>(__a)); }
151 
152  _GLIBCXX14_CONSTEXPR
153  inline const _Ios_Openmode&
154  operator|=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
155  { return __a = __a | __b; }
156 
157  _GLIBCXX14_CONSTEXPR
158  inline const _Ios_Openmode&
159  operator&=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
160  { return __a = __a & __b; }
161 
162  _GLIBCXX14_CONSTEXPR
163  inline const _Ios_Openmode&
164  operator^=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
165  { return __a = __a ^ __b; }
166 
167 
168  enum _Ios_Iostate
169  {
170  _S_goodbit = 0,
171  _S_badbit = 1L << 0,
172  _S_eofbit = 1L << 1,
173  _S_failbit = 1L << 2,
174  _S_ios_iostate_end = 1L << 16,
175  _S_ios_iostate_max = __INT_MAX__,
176  _S_ios_iostate_min = ~__INT_MAX__
177  };
178 
179  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
180  inline _Ios_Iostate
181  operator&(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
182  { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }
183 
184  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
185  inline _Ios_Iostate
186  operator|(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
187  { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }
188 
189  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
190  inline _Ios_Iostate
191  operator^(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
192  { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }
193 
194  _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
195  inline _Ios_Iostate
196  operator~(_Ios_Iostate __a) _GLIBCXX_NOTHROW
197  { return _Ios_Iostate(~static_cast<int>(__a)); }
198 
199  _GLIBCXX14_CONSTEXPR
200  inline const _Ios_Iostate&
201  operator|=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
202  { return __a = __a | __b; }
203 
204  _GLIBCXX14_CONSTEXPR
205  inline const _Ios_Iostate&
206  operator&=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
207  { return __a = __a & __b; }
208 
209  _GLIBCXX14_CONSTEXPR
210  inline const _Ios_Iostate&
211  operator^=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
212  { return __a = __a ^ __b; }
213 
214 
215  enum _Ios_Seekdir
216  {
217  _S_beg = 0,
218  _S_cur = _GLIBCXX_STDIO_SEEK_CUR,
219  _S_end = _GLIBCXX_STDIO_SEEK_END,
220  _S_ios_seekdir_end = 1L << 16
221  };
222 
223 #if __cplusplus >= 201103L
224  /// I/O error code
225  enum class io_errc { stream = 1 };
226 
227  template <> struct is_error_code_enum<io_errc> : public true_type { };
228 
229  [[__nodiscard__, __gnu__::__const__]]
230  const error_category&
231  iostream_category() noexcept;
232 
233  [[__nodiscard__]]
234  inline error_code
235  make_error_code(io_errc __e) noexcept
236  { return error_code(static_cast<int>(__e), iostream_category()); }
237 
238  [[__nodiscard__]]
239  inline error_condition
240  make_error_condition(io_errc __e) noexcept
241  { return error_condition(static_cast<int>(__e), iostream_category()); }
242 #endif
243 
244  // 27.4.2 Class ios_base
245  /**
246  * @brief The base of the I/O class hierarchy.
247  * @ingroup io
248  *
249  * This class defines everything that can be defined about I/O that does
250  * not depend on the type of characters being input or output. Most
251  * people will only see @c ios_base when they need to specify the full
252  * name of the various I/O flags (e.g., the openmodes).
253  */
254  class ios_base
255  {
256 #if _GLIBCXX_USE_CXX11_ABI
257 #if __cplusplus < 201103L
258  // Type that is layout-compatible with std::system_error
260  {
261  // Type that is layout-compatible with std::error_code
262  struct error_code
263  {
264  error_code() { }
265  private:
266  int _M_value;
267  const void* _M_cat;
268  } _M_code;
269  };
270 #endif
271 #endif
272  public:
273 
274  /**
275  * @brief These are thrown to indicate problems with io.
276  * @ingroup exceptions
277  *
278  * 27.4.2.1.1 Class ios_base::failure
279  */
280 #if _GLIBCXX_USE_CXX11_ABI
281  class _GLIBCXX_ABI_TAG_CXX11 failure : public system_error
282  {
283  public:
284  explicit
285  failure(const string& __str);
286 
287 #if __cplusplus >= 201103L
288  explicit
289  failure(const string&, const error_code&);
290 
291  explicit
292  failure(const char*, const error_code& = io_errc::stream);
293 #endif
294 
295  virtual
296  ~failure() throw();
297 
298  virtual const char*
299  what() const throw();
300  };
301 #else
302  class failure : public exception
303  {
304  public:
305  // _GLIBCXX_RESOLVE_LIB_DEFECTS
306  // 48. Use of non-existent exception constructor
307  explicit
308  failure(const string& __str) throw();
309 
310  // This declaration is not useless:
311  // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html
312  virtual
313  ~failure() throw();
314 
315  virtual const char*
316  what() const throw();
317 
318 #if __cplusplus >= 201103L
319  // Define the new members required by C++11,
320  // even though the error_code cannot be stored.
321 
322  explicit
323  failure(const string& __s, const error_code&) noexcept
324  : failure(__s)
325  { }
326 
327  explicit
328  failure(const char* __s, const error_code& = error_code{})
329  : failure(string(__s))
330  { }
331 
332  // Stand-in for system_error::code() but returning by value.
333  error_code code() const noexcept { return error_code{}; }
334 #endif
335 
336  private:
337  string _M_msg;
338  };
339 #endif
340 
341  // 27.4.2.1.2 Type ios_base::fmtflags
342  /**
343  * @brief This is a bitmask type.
344  *
345  * @c @a _Ios_Fmtflags is implementation-defined, but it is valid to
346  * perform bitwise operations on these values and expect the Right
347  * Thing to happen. Defined objects of type fmtflags are:
348  * - boolalpha
349  * - dec
350  * - fixed
351  * - hex
352  * - internal
353  * - left
354  * - oct
355  * - right
356  * - scientific
357  * - showbase
358  * - showpoint
359  * - showpos
360  * - skipws
361  * - unitbuf
362  * - uppercase
363  * - adjustfield
364  * - basefield
365  * - floatfield
366  */
367  typedef _Ios_Fmtflags fmtflags;
368 
369  /// Insert/extract @c bool in alphabetic rather than numeric format.
370  static const fmtflags boolalpha = _S_boolalpha;
371 
372  /// Converts integer input or generates integer output in decimal base.
373  static const fmtflags dec = _S_dec;
374 
375  /// Generate floating-point output in fixed-point notation.
376  static const fmtflags fixed = _S_fixed;
377 
378  /// Converts integer input or generates integer output in hexadecimal base.
379  static const fmtflags hex = _S_hex;
380 
381  /// Adds fill characters at a designated internal point in certain
382  /// generated output, or identical to @c right if no such point is
383  /// designated.
384  static const fmtflags internal = _S_internal;
385 
386  /// Adds fill characters on the right (final positions) of certain
387  /// generated output. (I.e., the thing you print is flush left.)
388  static const fmtflags left = _S_left;
389 
390  /// Converts integer input or generates integer output in octal base.
391  static const fmtflags oct = _S_oct;
392 
393  /// Adds fill characters on the left (initial positions) of certain
394  /// generated output. (I.e., the thing you print is flush right.)
395  static const fmtflags right = _S_right;
396 
397  /// Generates floating-point output in scientific notation.
398  static const fmtflags scientific = _S_scientific;
399 
400  /// Generates a prefix indicating the numeric base of generated integer
401  /// output.
402  static const fmtflags showbase = _S_showbase;
403 
404  /// Generates a decimal-point character unconditionally in generated
405  /// floating-point output.
406  static const fmtflags showpoint = _S_showpoint;
407 
408  /// Generates a + sign in non-negative generated numeric output.
409  static const fmtflags showpos = _S_showpos;
410 
411  /// Skips leading white space before certain input operations.
412  static const fmtflags skipws = _S_skipws;
413 
414  /// Flushes output after each output operation.
415  static const fmtflags unitbuf = _S_unitbuf;
416 
417  /// Replaces certain lowercase letters with their uppercase equivalents
418  /// in generated output.
419  static const fmtflags uppercase = _S_uppercase;
420 
421  /// A mask of left|right|internal. Useful for the 2-arg form of @c setf.
422  static const fmtflags adjustfield = _S_adjustfield;
423 
424  /// A mask of dec|oct|hex. Useful for the 2-arg form of @c setf.
425  static const fmtflags basefield = _S_basefield;
426 
427  /// A mask of scientific|fixed. Useful for the 2-arg form of @c setf.
428  static const fmtflags floatfield = _S_floatfield;
429 
430  // 27.4.2.1.3 Type ios_base::iostate
431  /**
432  * @brief This is a bitmask type.
433  *
434  * @c @a _Ios_Iostate is implementation-defined, but it is valid to
435  * perform bitwise operations on these values and expect the Right
436  * Thing to happen. Defined objects of type iostate are:
437  * - badbit
438  * - eofbit
439  * - failbit
440  * - goodbit
441  */
442  typedef _Ios_Iostate iostate;
443 
444  /// Indicates a loss of integrity in an input or output sequence (such
445  /// as an irrecoverable read error from a file).
446  static const iostate badbit = _S_badbit;
447 
448  /// Indicates that an input operation reached the end of an input sequence.
449  static const iostate eofbit = _S_eofbit;
450 
451  /// Indicates that an input operation failed to read the expected
452  /// characters, or that an output operation failed to generate the
453  /// desired characters.
454  static const iostate failbit = _S_failbit;
455 
456  /// Indicates all is well.
457  static const iostate goodbit = _S_goodbit;
458 
459  // 27.4.2.1.4 Type ios_base::openmode
460  /**
461  * @brief This is a bitmask type.
462  *
463  * @c @a _Ios_Openmode is implementation-defined, but it is valid to
464  * perform bitwise operations on these values and expect the Right
465  * Thing to happen. Defined objects of type openmode are:
466  * - app
467  * - ate
468  * - binary
469  * - in
470  * - out
471  * - trunc
472  */
473  typedef _Ios_Openmode openmode;
474 
475  /// Seek to end before each write.
476  static const openmode app = _S_app;
477 
478  /// Open and seek to end immediately after opening.
479  static const openmode ate = _S_ate;
480 
481  /// Perform input and output in binary mode (as opposed to text mode).
482  /// This is probably not what you think it is; see
483  /// https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
484  static const openmode binary = _S_bin;
485 
486  /// Open for input. Default for @c ifstream and fstream.
487  static const openmode in = _S_in;
488 
489  /// Open for output. Default for @c ofstream and fstream.
490  static const openmode out = _S_out;
491 
492  /// Truncate an existing stream when opening. Default for @c ofstream.
493  static const openmode trunc = _S_trunc;
494 
495  static const openmode __noreplace = _S_noreplace;
496 
497 #ifdef __glibcxx_ios_noreplace // C++ >= 23 && HOSTED
498  /// Open a file in exclusive mode.
499  static const openmode noreplace = _S_noreplace;
500 #endif
501 
502  // 27.4.2.1.5 Type ios_base::seekdir
503  /**
504  * @brief This is an enumerated type.
505  *
506  * @c @a _Ios_Seekdir is implementation-defined. Defined values
507  * of type seekdir are:
508  * - beg
509  * - cur, equivalent to @c SEEK_CUR in the C standard library.
510  * - end, equivalent to @c SEEK_END in the C standard library.
511  */
512  typedef _Ios_Seekdir seekdir;
513 
514  /// Request a seek relative to the beginning of the stream.
515  static const seekdir beg = _S_beg;
516 
517  /// Request a seek relative to the current position within the sequence.
518  static const seekdir cur = _S_cur;
519 
520  /// Request a seek relative to the current end of the sequence.
521  static const seekdir end = _S_end;
522 
523 #if __cplusplus <= 201402L
524  // Annex D.6 (removed in C++17)
525  typedef int io_state
526  _GLIBCXX_DEPRECATED_SUGGEST("std::iostate");
527  typedef int open_mode
528  _GLIBCXX_DEPRECATED_SUGGEST("std::openmode");
529  typedef int seek_dir
530  _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir");
531 
532  typedef std::streampos streampos
533  _GLIBCXX_DEPRECATED_SUGGEST("std::streampos");
534  typedef std::streamoff streamoff
535  _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff");
536 #endif
537 
538  // Callbacks;
539  /**
540  * @brief The set of events that may be passed to an event callback.
541  *
542  * erase_event is used during ~ios() and copyfmt(). imbue_event is used
543  * during imbue(). copyfmt_event is used during copyfmt().
544  */
545  enum event
546  {
547  erase_event,
548  imbue_event,
549  copyfmt_event
550  };
551 
552  /**
553  * @brief The type of an event callback function.
554  * @param __e One of the members of the event enum.
555  * @param __b Reference to the ios_base object.
556  * @param __i The integer provided when the callback was registered.
557  *
558  * Event callbacks are user defined functions that get called during
559  * several ios_base and basic_ios functions, specifically imbue(),
560  * copyfmt(), and ~ios().
561  */
562  typedef void (*event_callback) (event __e, ios_base& __b, int __i);
563 
564  /**
565  * @brief Add the callback __fn with parameter __index.
566  * @param __fn The function to add.
567  * @param __index The integer to pass to the function when invoked.
568  *
569  * Registers a function as an event callback with an integer parameter to
570  * be passed to the function when invoked. Multiple copies of the
571  * function are allowed. If there are multiple callbacks, they are
572  * invoked in the order they were registered.
573  */
574  void
575  register_callback(event_callback __fn, int __index);
576 
577  protected:
578  streamsize _M_precision;
579  streamsize _M_width;
580  fmtflags _M_flags;
581  iostate _M_exception;
582  iostate _M_streambuf_state;
583 
584  // 27.4.2.6 Members for callbacks
585  // 27.4.2.6 ios_base callbacks
586  struct _Callback_list
587  {
588  // Data Members
589  _Callback_list* _M_next;
591  int _M_index;
592  _Atomic_word _M_refcount; // 0 means one reference.
593 
594  _Callback_list(ios_base::event_callback __fn, int __index,
595  _Callback_list* __cb)
596  : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
597 
598  void
599  _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
600 
601  // 0 => OK to delete.
602  int
603  _M_remove_reference()
604  {
605  // Be race-detector-friendly. For more info see bits/c++config.
606  _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
607  int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1);
608  if (__res == 0)
609  {
610  _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
611  }
612  return __res;
613  }
614  };
615 
616  _Callback_list* _M_callbacks;
617 
618  void
619  _M_call_callbacks(event __ev) throw();
620 
621  void
622  _M_dispose_callbacks(void) throw();
623 
624  // 27.4.2.5 Members for iword/pword storage
625  struct _Words
626  {
627  void* _M_pword;
628  long _M_iword;
629  _Words() : _M_pword(0), _M_iword(0) { }
630  };
631 
632  // Only for failed iword/pword calls.
633  _Words _M_word_zero;
634 
635  // Guaranteed storage.
636  // The first 5 iword and pword slots are reserved for internal use.
637  enum { _S_local_word_size = 8 };
638  _Words _M_local_word[_S_local_word_size];
639 
640  // Allocated storage.
641  int _M_word_size;
642  _Words* _M_word;
643 
644  _Words&
645  _M_grow_words(int __index, bool __iword);
646 
647  // Members for locale and locale caching.
648  locale _M_ios_locale;
649 
650  void
651  _M_init() throw();
652 
653  public:
654 
655  // 27.4.2.1.6 Class ios_base::Init
656  // Used to initialize standard streams. In theory, g++ could use
657  // -finit-priority to order this stuff correctly without going
658  // through these machinations.
659  class Init
660  {
661  friend class ios_base;
662  public:
663  Init();
664  ~Init();
665 
666 #if __cplusplus >= 201103L
667  Init(const Init&) = default;
668  Init& operator=(const Init&) = default;
669 #endif
670 
671  private:
672  static _Atomic_word _S_refcount;
673  static bool _S_synced_with_stdio;
674  };
675 
676  // [27.4.2.2] fmtflags state functions
677  /**
678  * @brief Access to format flags.
679  * @return The format control flags for both input and output.
680  */
681  fmtflags
682  flags() const
683  { return _M_flags; }
684 
685  /**
686  * @brief Setting new format flags all at once.
687  * @param __fmtfl The new flags to set.
688  * @return The previous format control flags.
689  *
690  * This function overwrites all the format flags with @a __fmtfl.
691  */
692  fmtflags
693  flags(fmtflags __fmtfl)
694  {
695  fmtflags __old = _M_flags;
696  _M_flags = __fmtfl;
697  return __old;
698  }
699 
700  /**
701  * @brief Setting new format flags.
702  * @param __fmtfl Additional flags to set.
703  * @return The previous format control flags.
704  *
705  * This function sets additional flags in format control. Flags that
706  * were previously set remain set.
707  */
708  fmtflags
709  setf(fmtflags __fmtfl)
710  {
711  fmtflags __old = _M_flags;
712  _M_flags |= __fmtfl;
713  return __old;
714  }
715 
716  /**
717  * @brief Setting new format flags.
718  * @param __fmtfl Additional flags to set.
719  * @param __mask The flags mask for @a fmtfl.
720  * @return The previous format control flags.
721  *
722  * This function clears @a mask in the format flags, then sets
723  * @a fmtfl @c & @a mask. An example mask is @c ios_base::adjustfield.
724  */
725  fmtflags
726  setf(fmtflags __fmtfl, fmtflags __mask)
727  {
728  fmtflags __old = _M_flags;
729  _M_flags &= ~__mask;
730  _M_flags |= (__fmtfl & __mask);
731  return __old;
732  }
733 
734  /**
735  * @brief Clearing format flags.
736  * @param __mask The flags to unset.
737  *
738  * This function clears @a __mask in the format flags.
739  */
740  void
741  unsetf(fmtflags __mask)
742  { _M_flags &= ~__mask; }
743 
744  /**
745  * @brief Flags access.
746  * @return The precision to generate on certain output operations.
747  *
748  * Be careful if you try to give a definition of @a precision here; see
749  * DR 189.
750  */
751  streamsize
752  precision() const
753  { return _M_precision; }
754 
755  /**
756  * @brief Changing flags.
757  * @param __prec The new precision value.
758  * @return The previous value of precision().
759  */
760  streamsize
762  {
763  streamsize __old = _M_precision;
764  _M_precision = __prec;
765  return __old;
766  }
767 
768  /**
769  * @brief Flags access.
770  * @return The minimum field width to generate on output operations.
771  *
772  * <em>Minimum field width</em> refers to the number of characters.
773  */
774  streamsize
775  width() const
776  { return _M_width; }
777 
778  /**
779  * @brief Changing flags.
780  * @param __wide The new width value.
781  * @return The previous value of width().
782  */
783  streamsize
785  {
786  streamsize __old = _M_width;
787  _M_width = __wide;
788  return __old;
789  }
790 
791  // [27.4.2.4] ios_base static members
792  /**
793  * @brief Interaction with the standard C I/O objects.
794  * @param __sync Whether to synchronize or not.
795  * @return True if the standard streams were previously synchronized.
796  *
797  * The synchronization referred to is @e only that between the standard
798  * C facilities (e.g., stdout) and the standard C++ objects (e.g.,
799  * cout). User-declared streams are unaffected. See
800  * https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
801  */
802  static bool
803  sync_with_stdio(bool __sync = true);
804 
805  // [27.4.2.3] ios_base locale functions
806  /**
807  * @brief Setting a new locale.
808  * @param __loc The new locale.
809  * @return The previous locale.
810  *
811  * Sets the new locale for this stream, and then invokes each callback
812  * with imbue_event.
813  */
814  locale
815  imbue(const locale& __loc) throw();
816 
817  /**
818  * @brief Locale access
819  * @return A copy of the current locale.
820  *
821  * If @c imbue(loc) has previously been called, then this function
822  * returns @c loc. Otherwise, it returns a copy of @c std::locale(),
823  * the global C++ locale.
824  */
825  locale
826  getloc() const
827  { return _M_ios_locale; }
828 
829  /**
830  * @brief Locale access
831  * @return A reference to the current locale.
832  *
833  * Like getloc above, but returns a reference instead of
834  * generating a copy.
835  */
836  const locale&
837  _M_getloc() const
838  { return _M_ios_locale; }
839 
840  // [27.4.2.5] ios_base storage functions
841  /**
842  * @brief Access to unique indices.
843  * @return An integer different from all previous calls.
844  *
845  * This function returns a unique integer every time it is called. It
846  * can be used for any purpose, but is primarily intended to be a unique
847  * index for the iword and pword functions. The expectation is that an
848  * application calls xalloc in order to obtain an index in the iword and
849  * pword arrays that can be used without fear of conflict.
850  *
851  * The implementation maintains a static variable that is incremented and
852  * returned on each invocation. xalloc is guaranteed to return an index
853  * that is safe to use in the iword and pword arrays.
854  */
855  static int
856  xalloc() throw();
857 
858  /**
859  * @brief Access to integer array.
860  * @param __ix Index into the array.
861  * @return A reference to an integer associated with the index.
862  *
863  * The iword function provides access to an array of integers that can be
864  * used for any purpose. The array grows as required to hold the
865  * supplied index. All integers in the array are initialized to 0.
866  *
867  * The implementation reserves several indices. You should use xalloc to
868  * obtain an index that is safe to use. Also note that since the array
869  * can grow dynamically, it is not safe to hold onto the reference.
870  */
871  long&
872  iword(int __ix)
873  {
874  _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size)
875  ? _M_word[__ix] : _M_grow_words(__ix, true);
876  return __word._M_iword;
877  }
878 
879  /**
880  * @brief Access to void pointer array.
881  * @param __ix Index into the array.
882  * @return A reference to a void* associated with the index.
883  *
884  * The pword function provides access to an array of pointers that can be
885  * used for any purpose. The array grows as required to hold the
886  * supplied index. All pointers in the array are initialized to 0.
887  *
888  * The implementation reserves several indices. You should use xalloc to
889  * obtain an index that is safe to use. Also note that since the array
890  * can grow dynamically, it is not safe to hold onto the reference.
891  */
892  void*&
893  pword(int __ix)
894  {
895  _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size)
896  ? _M_word[__ix] : _M_grow_words(__ix, false);
897  return __word._M_pword;
898  }
899 
900  // Destructor
901  /**
902  * Invokes each callback with erase_event. Destroys local storage.
903  *
904  * Note that the ios_base object for the standard streams never gets
905  * destroyed. As a result, any callbacks registered with the standard
906  * streams will not get invoked with erase_event (unless copyfmt is
907  * used).
908  */
909  virtual ~ios_base();
910 
911  protected:
912  ios_base() throw ();
913 
914 #if __cplusplus < 201103L
915  // _GLIBCXX_RESOLVE_LIB_DEFECTS
916  // 50. Copy constructor and assignment operator of ios_base
917  private:
918  ios_base(const ios_base&);
919 
920  ios_base&
921  operator=(const ios_base&);
922 #else
923  public:
924  ios_base(const ios_base&) = delete;
925 
926  ios_base&
927  operator=(const ios_base&) = delete;
928 
929  protected:
930  void
931  _M_move(ios_base&) noexcept;
932 
933  void
934  _M_swap(ios_base& __rhs) noexcept;
935 #endif
936  };
937 
938  // [27.4.5.1] fmtflags manipulators
939  /// Calls base.setf(ios_base::boolalpha).
940  inline ios_base&
942  {
944  return __base;
945  }
946 
947  /// Calls base.unsetf(ios_base::boolalpha).
948  inline ios_base&
950  {
951  __base.unsetf(ios_base::boolalpha);
952  return __base;
953  }
954 
955  /// Calls base.setf(ios_base::showbase).
956  inline ios_base&
958  {
960  return __base;
961  }
962 
963  /// Calls base.unsetf(ios_base::showbase).
964  inline ios_base&
966  {
967  __base.unsetf(ios_base::showbase);
968  return __base;
969  }
970 
971  /// Calls base.setf(ios_base::showpoint).
972  inline ios_base&
974  {
976  return __base;
977  }
978 
979  /// Calls base.unsetf(ios_base::showpoint).
980  inline ios_base&
982  {
983  __base.unsetf(ios_base::showpoint);
984  return __base;
985  }
986 
987  /// Calls base.setf(ios_base::showpos).
988  inline ios_base&
990  {
992  return __base;
993  }
994 
995  /// Calls base.unsetf(ios_base::showpos).
996  inline ios_base&
998  {
999  __base.unsetf(ios_base::showpos);
1000  return __base;
1001  }
1002 
1003  /// Calls base.setf(ios_base::skipws).
1004  inline ios_base&
1006  {
1007  __base.setf(ios_base::skipws);
1008  return __base;
1009  }
1010 
1011  /// Calls base.unsetf(ios_base::skipws).
1012  inline ios_base&
1014  {
1015  __base.unsetf(ios_base::skipws);
1016  return __base;
1017  }
1018 
1019  /// Calls base.setf(ios_base::uppercase).
1020  inline ios_base&
1022  {
1024  return __base;
1025  }
1026 
1027  /// Calls base.unsetf(ios_base::uppercase).
1028  inline ios_base&
1030  {
1031  __base.unsetf(ios_base::uppercase);
1032  return __base;
1033  }
1034 
1035  /// Calls base.setf(ios_base::unitbuf).
1036  inline ios_base&
1038  {
1039  __base.setf(ios_base::unitbuf);
1040  return __base;
1041  }
1042 
1043  /// Calls base.unsetf(ios_base::unitbuf).
1044  inline ios_base&
1046  {
1047  __base.unsetf(ios_base::unitbuf);
1048  return __base;
1049  }
1050 
1051  // [27.4.5.2] adjustfield manipulators
1052  /// Calls base.setf(ios_base::internal, ios_base::adjustfield).
1053  inline ios_base&
1054  internal(ios_base& __base)
1055  {
1057  return __base;
1058  }
1059 
1060  /// Calls base.setf(ios_base::left, ios_base::adjustfield).
1061  inline ios_base&
1063  {
1065  return __base;
1066  }
1067 
1068  /// Calls base.setf(ios_base::right, ios_base::adjustfield).
1069  inline ios_base&
1071  {
1073  return __base;
1074  }
1075 
1076  // [27.4.5.3] basefield manipulators
1077  /// Calls base.setf(ios_base::dec, ios_base::basefield).
1078  inline ios_base&
1080  {
1082  return __base;
1083  }
1084 
1085  /// Calls base.setf(ios_base::hex, ios_base::basefield).
1086  inline ios_base&
1088  {
1090  return __base;
1091  }
1092 
1093  /// Calls base.setf(ios_base::oct, ios_base::basefield).
1094  inline ios_base&
1096  {
1098  return __base;
1099  }
1100 
1101  // [27.4.5.4] floatfield manipulators
1102  /// Calls base.setf(ios_base::fixed, ios_base::floatfield).
1103  inline ios_base&
1105  {
1107  return __base;
1108  }
1109 
1110  /// Calls base.setf(ios_base::scientific, ios_base::floatfield).
1111  inline ios_base&
1113  {
1115  return __base;
1116  }
1117 
1118 #if __cplusplus >= 201103L
1119  // New C++11 floatfield manipulators
1120 
1121  /// Calls
1122  /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield)
1123  inline ios_base&
1125  {
1127  return __base;
1128  }
1129 
1130  /// Calls @c base.unsetf(ios_base::floatfield)
1131  inline ios_base&
1133  {
1134  __base.unsetf(ios_base::floatfield);
1135  return __base;
1136  }
1137 #endif
1138 
1139 _GLIBCXX_END_NAMESPACE_VERSION
1140 } // namespace
1141 
1142 #endif /* _IOS_BASE_H */
ISO C++ entities toplevel namespace is std.
ios_base & noskipws(ios_base &__base)
Calls base.unsetf(ios_base::skipws).
Definition: ios_base.h:1013
long long streamoff
Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
Definition: postypes.h:64
virtual ~ios_base()
ios_base & showpos(ios_base &__base)
Calls base.setf(ios_base::showpos).
Definition: ios_base.h:989
static const fmtflags showpoint
Generates a decimal-point character unconditionally in generated floating-point output.
Definition: ios_base.h:406
ios_base & nounitbuf(ios_base &__base)
Calls base.unsetf(ios_base::unitbuf).
Definition: ios_base.h:1045
io_errc
I/O error code.
Definition: ios_base.h:225
ios_base & hexfloat(ios_base &__base)
Calls base.setf(ios_base::fixed|ios_basescientific, ios_base::floatfield)
Definition: ios_base.h:1124
ios_base & nouppercase(ios_base &__base)
Calls base.unsetf(ios_base::uppercase).
Definition: ios_base.h:1029
static const iostate badbit
Indicates a loss of integrity in an input or output sequence (such as an irrecoverable read error fro...
Definition: ios_base.h:446
static const openmode trunc
Truncate an existing stream when opening. Default for ofstream.
Definition: ios_base.h:493
ios_base & right(ios_base &__base)
Calls base.setf(ios_base::right, ios_base::adjustfield).
Definition: ios_base.h:1070
ios_base & noshowbase(ios_base &__base)
Calls base.unsetf(ios_base::showbase).
Definition: ios_base.h:965
static const fmtflags hex
Converts integer input or generates integer output in hexadecimal base.
Definition: ios_base.h:379
ios_base & uppercase(ios_base &__base)
Calls base.setf(ios_base::uppercase).
Definition: ios_base.h:1021
static const fmtflags boolalpha
Insert/extract bool in alphabetic rather than numeric format.
Definition: ios_base.h:370
An exception type that includes an error_code value.
Definition: system_error:556
static const fmtflags adjustfield
A mask of left|right|internal. Useful for the 2-arg form of setf.
Definition: ios_base.h:422
Class representing stream positions.
Definition: postypes.h:82
constexpr bitset< _Nb > operator &(const bitset< _Nb > &__x, const bitset< _Nb > &__y) noexcept
Global bitwise operations on bitsets.
Definition: bitset:1557
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition: postypes.h:68
constexpr _Iterator __base(_Iterator __it)
static const openmode binary
Perform input and output in binary mode (as opposed to text mode). This is probably not what you thin...
Definition: ios_base.h:484
ios_base & noboolalpha(ios_base &__base)
Calls base.unsetf(ios_base::boolalpha).
Definition: ios_base.h:949
static const fmtflags dec
Converts integer input or generates integer output in decimal base.
Definition: ios_base.h:373
static const openmode in
Open for input. Default for ifstream and fstream.
Definition: ios_base.h:487
static const openmode ate
Open and seek to end immediately after opening.
Definition: ios_base.h:479
static const iostate failbit
Indicates that an input operation failed to read the expected characters, or that an output operation...
Definition: ios_base.h:454
Container class for localization functionality.The locale class is first a class wrapper for C librar...
static bool sync_with_stdio(bool __sync=true)
Interaction with the standard C I/O objects.
streamsize precision(streamsize __prec)
Changing flags.
Definition: ios_base.h:761
void register_callback(event_callback __fn, int __index)
Add the callback __fn with parameter __index.
constexpr bitset< _Nb > operator^(const bitset< _Nb > &__x, const bitset< _Nb > &__y) noexcept
Global bitwise operations on bitsets.
Definition: bitset:1577
ios_base & dec(ios_base &__base)
Calls base.setf(ios_base::dec, ios_base::basefield).
Definition: ios_base.h:1079
error_code make_error_code(future_errc __errc) noexcept
Overload of make_error_code for future_errc.
Definition: future:94
static const openmode out
Open for output. Default for ofstream and fstream.
Definition: ios_base.h:490
ios_base & showbase(ios_base &__base)
Calls base.setf(ios_base::showbase).
Definition: ios_base.h:957
static const openmode app
Seek to end before each write.
Definition: ios_base.h:476
streamsize precision() const
Flags access.
Definition: ios_base.h:752
_Ios_Fmtflags fmtflags
This is a bitmask type.
Definition: ios_base.h:367
ios_base & noshowpoint(ios_base &__base)
Calls base.unsetf(ios_base::showpoint).
Definition: ios_base.h:981
fmtflags setf(fmtflags __fmtfl, fmtflags __mask)
Setting new format flags.
Definition: ios_base.h:726
ios_base & unitbuf(ios_base &__base)
Calls base.setf(ios_base::unitbuf).
Definition: ios_base.h:1037
static const fmtflags right
Adds fill characters on the left (initial positions) of certain generated output. (I...
Definition: ios_base.h:395
virtual const char * what() const
static const fmtflags skipws
Skips leading white space before certain input operations.
Definition: ios_base.h:412
ios_base & scientific(ios_base &__base)
Calls base.setf(ios_base::scientific, ios_base::floatfield).
Definition: ios_base.h:1112
fmtflags setf(fmtflags __fmtfl)
Setting new format flags.
Definition: ios_base.h:709
long & iword(int __ix)
Access to integer array.
Definition: ios_base.h:872
ios_base & boolalpha(ios_base &__base)
Calls base.setf(ios_base::boolalpha).
Definition: ios_base.h:941
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:111
static const fmtflags left
Adds fill characters on the right (final positions) of certain generated output. (I.e., the thing you print is flush left.)
Definition: ios_base.h:388
ios_base & hex(ios_base &__base)
Calls base.setf(ios_base::hex, ios_base::basefield).
Definition: ios_base.h:1087
The base of the I/O class hierarchy.This class defines everything that can be defined about I/O that ...
Definition: ios_base.h:254
void unsetf(fmtflags __mask)
Clearing format flags.
Definition: ios_base.h:741
static const fmtflags basefield
A mask of dec|oct|hex. Useful for the 2-arg form of setf.
Definition: ios_base.h:425
static const fmtflags showbase
Generates a prefix indicating the numeric base of generated integer output.
Definition: ios_base.h:402
void(* event_callback)(event __e, ios_base &__b, int __i)
The type of an event callback function.
Definition: ios_base.h:562
void *& pword(int __ix)
Access to void pointer array.
Definition: ios_base.h:893
fmtflags flags(fmtflags __fmtfl)
Setting new format flags all at once.
Definition: ios_base.h:693
static const fmtflags scientific
Generates floating-point output in scientific notation.
Definition: ios_base.h:398
static const fmtflags showpos
Generates a + sign in non-negative generated numeric output.
Definition: ios_base.h:409
static const iostate eofbit
Indicates that an input operation reached the end of an input sequence.
Definition: ios_base.h:449
const locale & _M_getloc() const
Locale access.
Definition: ios_base.h:837
streamsize width() const
Flags access.
Definition: ios_base.h:775
ios_base & oct(ios_base &__base)
Calls base.setf(ios_base::oct, ios_base::basefield).
Definition: ios_base.h:1095
_Ios_Iostate iostate
This is a bitmask type.
Definition: ios_base.h:442
static int xalloc()
Access to unique indices.
static const fmtflags uppercase
Replaces certain lowercase letters with their uppercase equivalents in generated output.
Definition: ios_base.h:419
ios_base & showpoint(ios_base &__base)
Calls base.setf(ios_base::showpoint).
Definition: ios_base.h:973
Base class for all library exceptions.
Definition: exception.h:59
locale imbue(const locale &__loc)
Setting a new locale.
constexpr bitset< _Nb > operator|(const bitset< _Nb > &__x, const bitset< _Nb > &__y) noexcept
Global bitwise operations on bitsets.
Definition: bitset:1567
ios_base & defaultfloat(ios_base &__base)
Calls base.unsetf(ios_base::floatfield)
Definition: ios_base.h:1132
static const iostate goodbit
Indicates all is well.
Definition: ios_base.h:457
static const seekdir end
Request a seek relative to the current end of the sequence.
Definition: ios_base.h:521
ios_base & noshowpos(ios_base &__base)
Calls base.unsetf(ios_base::showpos).
Definition: ios_base.h:997
static const fmtflags fixed
Generate floating-point output in fixed-point notation.
Definition: ios_base.h:376
static const fmtflags oct
Converts integer input or generates integer output in octal base.
Definition: ios_base.h:391
locale getloc() const
Locale access.
Definition: ios_base.h:826
static const fmtflags internal
Adds fill characters at a designated internal point in certain generated output, or identical to righ...
Definition: ios_base.h:384
static const fmtflags unitbuf
Flushes output after each output operation.
Definition: ios_base.h:415
static const fmtflags floatfield
A mask of scientific|fixed. Useful for the 2-arg form of setf.
Definition: ios_base.h:428
event
The set of events that may be passed to an event callback.
Definition: ios_base.h:545
One of two subclasses of exception.
Definition: stdexcept:219
error_condition make_error_condition(future_errc __errc) noexcept
Overload of make_error_condition for future_errc.
Definition: future:100
_Ios_Openmode openmode
This is a bitmask type.
Definition: ios_base.h:473
streamsize width(streamsize __wide)
Changing flags.
Definition: ios_base.h:784
static const seekdir cur
Request a seek relative to the current position within the sequence.
Definition: ios_base.h:518
static const seekdir beg
Request a seek relative to the beginning of the stream.
Definition: ios_base.h:515
ios_base & fixed(ios_base &__base)
Calls base.setf(ios_base::fixed, ios_base::floatfield).
Definition: ios_base.h:1104
ios_base & left(ios_base &__base)
Calls base.setf(ios_base::left, ios_base::adjustfield).
Definition: ios_base.h:1062
_Ios_Seekdir seekdir
This is an enumerated type.
Definition: ios_base.h:512
These are thrown to indicate problems with io.27.4.2.1.1 Class ios_base::failure. ...
Definition: ios_base.h:302
ios_base & skipws(ios_base &__base)
Calls base.setf(ios_base::skipws).
Definition: ios_base.h:1005
fmtflags flags() const
Access to format flags.
Definition: ios_base.h:682