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ios_base.h
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1// Iostreams base classes -*- C++ -*-
2
3// Copyright (C) 1997-2026 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#ifdef _GLIBCXX_SYSHDR
38#pragma GCC system_header
39#endif
40
41#include <ext/atomicity.h>
42#include <bits/localefwd.h>
43#include <bits/locale_classes.h>
44
45#if __cplusplus < 201103L
46# include <stdexcept>
47#else
48# include <system_error>
49#endif
50
51namespace std _GLIBCXX_VISIBILITY(default)
52{
53_GLIBCXX_BEGIN_NAMESPACE_VERSION
54
55 // The following definitions of bitmask types are enums, not ints,
56 // as permitted (but not required) in the standard, in order to provide
57 // better type safety in iostream calls. A side effect is that in C++98
58 // expressions involving them are not compile-time constants.
59 enum __attribute__((__flag_enum__)) _Ios_Fmtflags
60 {
61 _S_boolalpha = 1L << 0,
62 _S_dec = 1L << 1,
63 _S_fixed = 1L << 2,
64 _S_hex = 1L << 3,
65 _S_internal = 1L << 4,
66 _S_left = 1L << 5,
67 _S_oct = 1L << 6,
68 _S_right = 1L << 7,
69 _S_scientific = 1L << 8,
70 _S_showbase = 1L << 9,
71 _S_showpoint = 1L << 10,
72 _S_showpos = 1L << 11,
73 _S_skipws = 1L << 12,
74 _S_unitbuf = 1L << 13,
75 _S_uppercase = 1L << 14,
76 _S_adjustfield = _S_left | _S_right | _S_internal,
77 _S_basefield = _S_dec | _S_oct | _S_hex,
78 _S_floatfield = _S_scientific | _S_fixed,
79 _S_ios_fmtflags_end __attribute__((__unused__)) = 1L << 16,
80 _S_ios_fmtflags_max __attribute__((__unused__)) = __INT_MAX__,
81 _S_ios_fmtflags_min __attribute__((__unused__)) = ~__INT_MAX__
82 };
83
84 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
85 inline _Ios_Fmtflags
86 operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
87 { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }
88
89 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
90 inline _Ios_Fmtflags
91 operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
92 { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }
93
94 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
95 inline _Ios_Fmtflags
96 operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
97 { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }
98
99 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
100 inline _Ios_Fmtflags
101 operator~(_Ios_Fmtflags __a) _GLIBCXX_NOTHROW
102 { return _Ios_Fmtflags(~static_cast<int>(__a)); }
103
104 _GLIBCXX14_CONSTEXPR
105 inline const _Ios_Fmtflags&
106 operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
107 { return __a = __a | __b; }
108
109 _GLIBCXX14_CONSTEXPR
110 inline const _Ios_Fmtflags&
111 operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
112 { return __a = __a & __b; }
113
114 _GLIBCXX14_CONSTEXPR
115 inline const _Ios_Fmtflags&
116 operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
117 { return __a = __a ^ __b; }
118
119 // If std::ios_base::noreplace isn't available, -Wswitch should ignore
120 // _S_noreplace.
121#ifdef __glibcxx_ios_noreplace
122#define _NOREPLACE_UNUSED
123#else
124#define _NOREPLACE_UNUSED __attribute__((__unused__))
125#endif
126
127 enum __attribute__((__flag_enum__)) _Ios_Openmode
128 {
129 _S_app = 1L << 0,
130 _S_ate = 1L << 1,
131 _S_bin = 1L << 2,
132 _S_in = 1L << 3,
133 _S_out = 1L << 4,
134 _S_trunc = 1L << 5,
135 _S_noreplace _NOREPLACE_UNUSED = 1L << 6,
136 _S_ios_openmode_end __attribute__((__unused__)) = 1L << 16,
137 _S_ios_openmode_max __attribute__((__unused__)) = __INT_MAX__,
138 _S_ios_openmode_min __attribute__((__unused__)) = ~__INT_MAX__
139 };
140
141#undef _NOREPLACE_UNUSED
142
143 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
144 inline _Ios_Openmode
145 operator&(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
146 { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }
147
148 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
149 inline _Ios_Openmode
150 operator|(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
151 { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }
152
153 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
154 inline _Ios_Openmode
155 operator^(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
156 { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }
157
158 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
159 inline _Ios_Openmode
160 operator~(_Ios_Openmode __a) _GLIBCXX_NOTHROW
161 { return _Ios_Openmode(~static_cast<int>(__a)); }
162
163 _GLIBCXX14_CONSTEXPR
164 inline const _Ios_Openmode&
165 operator|=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
166 { return __a = __a | __b; }
167
168 _GLIBCXX14_CONSTEXPR
169 inline const _Ios_Openmode&
170 operator&=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
171 { return __a = __a & __b; }
172
173 _GLIBCXX14_CONSTEXPR
174 inline const _Ios_Openmode&
175 operator^=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
176 { return __a = __a ^ __b; }
177
178
179 enum __attribute__((__flag_enum__)) _Ios_Iostate
180 {
181 _S_goodbit = 0,
182 _S_badbit = 1L << 0,
183 _S_eofbit = 1L << 1,
184 _S_failbit = 1L << 2,
185 _S_ios_iostate_end __attribute__((__unused__)) = 1L << 16,
186 _S_ios_iostate_max __attribute__((__unused__)) = __INT_MAX__,
187 _S_ios_iostate_min __attribute__((__unused__)) = ~__INT_MAX__
188 };
189
190 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
191 inline _Ios_Iostate
192 operator&(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
193 { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }
194
195 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
196 inline _Ios_Iostate
197 operator|(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
198 { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }
199
200 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
201 inline _Ios_Iostate
202 operator^(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
203 { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }
204
205 _GLIBCXX_NODISCARD _GLIBCXX_CONSTEXPR
206 inline _Ios_Iostate
207 operator~(_Ios_Iostate __a) _GLIBCXX_NOTHROW
208 { return _Ios_Iostate(~static_cast<int>(__a)); }
209
210 _GLIBCXX14_CONSTEXPR
211 inline const _Ios_Iostate&
212 operator|=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
213 { return __a = __a | __b; }
214
215 _GLIBCXX14_CONSTEXPR
216 inline const _Ios_Iostate&
217 operator&=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
218 { return __a = __a & __b; }
219
220 _GLIBCXX14_CONSTEXPR
221 inline const _Ios_Iostate&
222 operator^=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
223 { return __a = __a ^ __b; }
224
225
226 enum _Ios_Seekdir
227 {
228 _S_beg = 0,
229 _S_cur = _GLIBCXX_STDIO_SEEK_CUR,
230 _S_end = _GLIBCXX_STDIO_SEEK_END,
231 _S_ios_seekdir_end __attribute__((__unused__)) = 1L << 16
232 };
233
234#if __cplusplus >= 201103L
235 /// I/O error code
236 enum class io_errc { stream = 1 };
237
238 template <> struct is_error_code_enum<io_errc> : public true_type { };
239
240 [[__nodiscard__, __gnu__::__const__]]
241 const error_category&
242 iostream_category() noexcept;
243
244 [[__nodiscard__]]
245 inline error_code
246 make_error_code(io_errc __e) noexcept
247 { return error_code(static_cast<int>(__e), iostream_category()); }
248
249 [[__nodiscard__]]
250 inline error_condition
251 make_error_condition(io_errc __e) noexcept
252 { return error_condition(static_cast<int>(__e), iostream_category()); }
253#endif
254
255 // 27.4.2 Class ios_base
256 /**
257 * @brief The base of the I/O class hierarchy.
258 * @ingroup io
259 *
260 * This class defines everything that can be defined about I/O that does
261 * not depend on the type of characters being input or output. Most
262 * people will only see @c ios_base when they need to specify the full
263 * name of the various I/O flags (e.g., the openmodes).
264 */
265 class ios_base
266 {
267#if _GLIBCXX_USE_CXX11_ABI
268#if __cplusplus < 201103L
269 // Type that is layout-compatible with std::system_error
270 struct system_error : std::runtime_error
271 {
272 // Type that is layout-compatible with std::error_code
273 struct error_code
274 {
275 error_code() { }
276 private:
277 int _M_value;
278 const void* _M_cat;
279 } _M_code;
280 };
281#endif
282#endif
283 public:
284
285 /**
286 * @brief These are thrown to indicate problems with io.
287 * @ingroup exceptions
288 *
289 * 27.4.2.1.1 Class ios_base::failure
290 */
291#if _GLIBCXX_USE_CXX11_ABI
292 class _GLIBCXX_ABI_TAG_CXX11 failure : public system_error
293 {
294 public:
295 explicit
296 failure(const string& __str);
297
298#if __cplusplus >= 201103L
299 explicit
300 failure(const string&, const error_code&);
301
302 explicit
303 failure(const char*, const error_code& = io_errc::stream);
304#endif
305
306 virtual
307 ~failure() throw();
308
309 virtual const char*
310 what() const throw();
311 };
312#else
313 class failure : public exception
314 {
315 public:
316 // _GLIBCXX_RESOLVE_LIB_DEFECTS
317 // 48. Use of non-existent exception constructor
318 explicit
319 failure(const string& __str) throw();
320
321 // This declaration is not useless:
322 // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html
323 virtual
324 ~failure() throw();
325
326 virtual const char*
327 what() const throw();
328
329#if __cplusplus >= 201103L
330 // Define the new members required by C++11,
331 // even though the error_code cannot be stored.
332
333 explicit
334 failure(const string& __s, const error_code&) noexcept
335 : failure(__s)
336 { }
337
338 explicit
339 failure(const char* __s, const error_code& = error_code{})
340 : failure(string(__s))
341 { }
342
343 // Stand-in for system_error::code() but returning by value.
344 error_code code() const noexcept { return error_code{}; }
345#endif
346
347 private:
348 string _M_msg;
349 };
350#endif
351
352 // 27.4.2.1.2 Type ios_base::fmtflags
353 /**
354 * @brief This is a bitmask type.
355 *
356 * @c @a _Ios_Fmtflags is implementation-defined, but it is valid to
357 * perform bitwise operations on these values and expect the Right
358 * Thing to happen. Defined objects of type fmtflags are:
359 * - boolalpha
360 * - dec
361 * - fixed
362 * - hex
363 * - internal
364 * - left
365 * - oct
366 * - right
367 * - scientific
368 * - showbase
369 * - showpoint
370 * - showpos
371 * - skipws
372 * - unitbuf
373 * - uppercase
374 * - adjustfield
375 * - basefield
376 * - floatfield
377 */
378 typedef _Ios_Fmtflags fmtflags;
379
380 /// Insert/extract @c bool in alphabetic rather than numeric format.
381 static const fmtflags boolalpha = _S_boolalpha;
382
383 /// Converts integer input or generates integer output in decimal base.
384 static const fmtflags dec = _S_dec;
385
386 /// Generate floating-point output in fixed-point notation.
387 static const fmtflags fixed = _S_fixed;
388
389 /// Converts integer input or generates integer output in hexadecimal base.
390 static const fmtflags hex = _S_hex;
391
392 /// Adds fill characters at a designated internal point in certain
393 /// generated output, or identical to @c right if no such point is
394 /// designated.
395 static const fmtflags internal = _S_internal;
396
397 /// Adds fill characters on the right (final positions) of certain
398 /// generated output. (I.e., the thing you print is flush left.)
399 static const fmtflags left = _S_left;
400
401 /// Converts integer input or generates integer output in octal base.
402 static const fmtflags oct = _S_oct;
403
404 /// Adds fill characters on the left (initial positions) of certain
405 /// generated output. (I.e., the thing you print is flush right.)
406 static const fmtflags right = _S_right;
407
408 /// Generates floating-point output in scientific notation.
409 static const fmtflags scientific = _S_scientific;
410
411 /// Generates a prefix indicating the numeric base of generated integer
412 /// output.
413 static const fmtflags showbase = _S_showbase;
414
415 /// Generates a decimal-point character unconditionally in generated
416 /// floating-point output.
417 static const fmtflags showpoint = _S_showpoint;
418
419 /// Generates a + sign in non-negative generated numeric output.
420 static const fmtflags showpos = _S_showpos;
421
422 /// Skips leading white space before certain input operations.
423 static const fmtflags skipws = _S_skipws;
424
425 /// Flushes output after each output operation.
426 static const fmtflags unitbuf = _S_unitbuf;
427
428 /// Replaces certain lowercase letters with their uppercase equivalents
429 /// in generated output.
430 static const fmtflags uppercase = _S_uppercase;
431
432 /// A mask of left|right|internal. Useful for the 2-arg form of @c setf.
433 static const fmtflags adjustfield = _S_adjustfield;
434
435 /// A mask of dec|oct|hex. Useful for the 2-arg form of @c setf.
436 static const fmtflags basefield = _S_basefield;
437
438 /// A mask of scientific|fixed. Useful for the 2-arg form of @c setf.
439 static const fmtflags floatfield = _S_floatfield;
440
441 // 27.4.2.1.3 Type ios_base::iostate
442 /**
443 * @brief This is a bitmask type.
444 *
445 * @c @a _Ios_Iostate is implementation-defined, but it is valid to
446 * perform bitwise operations on these values and expect the Right
447 * Thing to happen. Defined objects of type iostate are:
448 * - badbit
449 * - eofbit
450 * - failbit
451 * - goodbit
452 */
453 typedef _Ios_Iostate iostate;
454
455 /// Indicates a loss of integrity in an input or output sequence (such
456 /// as an irrecoverable read error from a file).
457 static const iostate badbit = _S_badbit;
458
459 /// Indicates that an input operation reached the end of an input sequence.
460 static const iostate eofbit = _S_eofbit;
461
462 /// Indicates that an input operation failed to read the expected
463 /// characters, or that an output operation failed to generate the
464 /// desired characters.
465 static const iostate failbit = _S_failbit;
466
467 /// Indicates all is well.
468 static const iostate goodbit = _S_goodbit;
469
470 // 27.4.2.1.4 Type ios_base::openmode
471 /**
472 * @brief This is a bitmask type.
473 *
474 * @c @a _Ios_Openmode is implementation-defined, but it is valid to
475 * perform bitwise operations on these values and expect the Right
476 * Thing to happen. Defined objects of type openmode are:
477 * - app
478 * - ate
479 * - binary
480 * - in
481 * - out
482 * - trunc
483 */
484 typedef _Ios_Openmode openmode;
485
486 /// Seek to end before each write.
487 static const openmode app = _S_app;
488
489 /// Open and seek to end immediately after opening.
490 static const openmode ate = _S_ate;
491
492 /// Perform input and output in binary mode (as opposed to text mode).
493 /// This is probably not what you think it is; see
494 /// https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
495 static const openmode binary = _S_bin;
496
497 /// Open for input. Default for @c ifstream and fstream.
498 static const openmode in = _S_in;
499
500 /// Open for output. Default for @c ofstream and fstream.
501 static const openmode out = _S_out;
502
503 /// Truncate an existing stream when opening. Default for @c ofstream.
504 static const openmode trunc = _S_trunc;
505
506 static const openmode __noreplace = _S_noreplace;
507
508#ifdef __glibcxx_ios_noreplace // C++ >= 23 && HOSTED
509 /// Open a file in exclusive mode.
510 static const openmode noreplace = _S_noreplace;
511#endif
512
513 // 27.4.2.1.5 Type ios_base::seekdir
514 /**
515 * @brief This is an enumerated type.
516 *
517 * @c @a _Ios_Seekdir is implementation-defined. Defined values
518 * of type seekdir are:
519 * - beg
520 * - cur, equivalent to @c SEEK_CUR in the C standard library.
521 * - end, equivalent to @c SEEK_END in the C standard library.
522 */
523 typedef _Ios_Seekdir seekdir;
524
525 /// Request a seek relative to the beginning of the stream.
526 static const seekdir beg = _S_beg;
527
528 /// Request a seek relative to the current position within the sequence.
529 static const seekdir cur = _S_cur;
530
531 /// Request a seek relative to the current end of the sequence.
532 static const seekdir end = _S_end;
533
534#if __cplusplus <= 201402L
535 // Annex D.6 (removed in C++17)
536 typedef int io_state
537 _GLIBCXX_DEPRECATED_SUGGEST("std::iostate");
538 typedef int open_mode
539 _GLIBCXX_DEPRECATED_SUGGEST("std::openmode");
540 typedef int seek_dir
541 _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir");
542
543 typedef std::streampos streampos
544 _GLIBCXX_DEPRECATED_SUGGEST("std::streampos");
545 typedef std::streamoff streamoff
546 _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff");
547#endif
548
549 // Callbacks;
550 /**
551 * @brief The set of events that may be passed to an event callback.
552 *
553 * erase_event is used during ~ios() and copyfmt(). imbue_event is used
554 * during imbue(). copyfmt_event is used during copyfmt().
555 */
556 enum event
557 {
558 erase_event,
559 imbue_event,
560 copyfmt_event
561 };
562
563 /**
564 * @brief The type of an event callback function.
565 * @param __e One of the members of the event enum.
566 * @param __b Reference to the ios_base object.
567 * @param __i The integer provided when the callback was registered.
568 *
569 * Event callbacks are user defined functions that get called during
570 * several ios_base and basic_ios functions, specifically imbue(),
571 * copyfmt(), and ~ios().
572 */
573 typedef void (*event_callback) (event __e, ios_base& __b, int __i);
574
575 /**
576 * @brief Add the callback __fn with parameter __index.
577 * @param __fn The function to add.
578 * @param __index The integer to pass to the function when invoked.
579 *
580 * Registers a function as an event callback with an integer parameter to
581 * be passed to the function when invoked. Multiple copies of the
582 * function are allowed. If there are multiple callbacks, they are
583 * invoked in the order they were registered.
584 */
585 void
586 register_callback(event_callback __fn, int __index);
587
588 protected:
589 streamsize _M_precision;
590 streamsize _M_width;
591 fmtflags _M_flags;
592 iostate _M_exception;
593 iostate _M_streambuf_state;
594
595 // 27.4.2.6 Members for callbacks
596 // 27.4.2.6 ios_base callbacks
597 struct _Callback_list
598 {
599 // Data Members
600 _Callback_list* _M_next;
601 ios_base::event_callback _M_fn;
602 int _M_index;
603 _Atomic_word _M_refcount; // 0 means one reference.
604
605 _Callback_list(ios_base::event_callback __fn, int __index,
606 _Callback_list* __cb)
607 : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
608
609 void
610 _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
611
612 // 0 => OK to delete.
613 int
614 _M_remove_reference()
615 {
616 // Be race-detector-friendly. For more info see bits/c++config.
617 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
618 int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1);
619 if (__res == 0)
620 {
621 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
622 }
623 return __res;
624 }
625 };
626
627 _Callback_list* _M_callbacks;
628
629 void
630 _M_call_callbacks(event __ev) throw();
631
632 void
633 _M_dispose_callbacks(void) throw();
634
635 // 27.4.2.5 Members for iword/pword storage
636 struct _Words
637 {
638 void* _M_pword;
639 long _M_iword;
640 _Words() : _M_pword(0), _M_iword(0) { }
641 };
642
643 // Only for failed iword/pword calls.
644 _Words _M_word_zero;
645
646 // Guaranteed storage.
647 // The first 5 iword and pword slots are reserved for internal use.
648 enum { _S_local_word_size = 8 };
649 _Words _M_local_word[_S_local_word_size];
650
651 // Allocated storage.
652 int _M_word_size;
653 _Words* _M_word;
654
655 _Words&
656 _M_grow_words(int __index, bool __iword);
657
658 // Members for locale and locale caching.
659 locale _M_ios_locale;
660
661 void
662 _M_init() throw();
663
664 public:
665
666 // 27.4.2.1.6 Class ios_base::Init
667 // Used to initialize standard streams. In theory, g++ could use
668 // -finit-priority to order this stuff correctly without going
669 // through these machinations.
670 class Init
671 {
672 friend class ios_base;
673 public:
674 Init();
675 ~Init();
676
677#if __cplusplus >= 201103L
678 Init(const Init&) = default;
679 Init& operator=(const Init&) = default;
680#endif
681
682 private:
683 static _Atomic_word _S_refcount;
684 static bool _S_synced_with_stdio;
685 };
686
687 // [27.4.2.2] fmtflags state functions
688 /**
689 * @brief Access to format flags.
690 * @return The format control flags for both input and output.
691 */
692 _GLIBCXX_NODISCARD
693 fmtflags
694 flags() const
695 { return _M_flags; }
696
697 /**
698 * @brief Setting new format flags all at once.
699 * @param __fmtfl The new flags to set.
700 * @return The previous format control flags.
701 *
702 * This function overwrites all the format flags with @a __fmtfl.
703 */
704 fmtflags
705 flags(fmtflags __fmtfl)
706 {
707 fmtflags __old = _M_flags;
708 _M_flags = __fmtfl;
709 return __old;
710 }
711
712 /**
713 * @brief Setting new format flags.
714 * @param __fmtfl Additional flags to set.
715 * @return The previous format control flags.
716 *
717 * This function sets additional flags in format control. Flags that
718 * were previously set remain set.
719 */
720 fmtflags
721 setf(fmtflags __fmtfl)
722 {
723 fmtflags __old = _M_flags;
724 _M_flags |= __fmtfl;
725 return __old;
726 }
727
728 /**
729 * @brief Setting new format flags.
730 * @param __fmtfl Additional flags to set.
731 * @param __mask The flags mask for @a fmtfl.
732 * @return The previous format control flags.
733 *
734 * This function clears @a mask in the format flags, then sets
735 * @a fmtfl @c & @a mask. An example mask is @c ios_base::adjustfield.
736 */
737 fmtflags
738 setf(fmtflags __fmtfl, fmtflags __mask)
739 {
740 fmtflags __old = _M_flags;
741 _M_flags &= ~__mask;
742 _M_flags |= (__fmtfl & __mask);
743 return __old;
744 }
745
746 /**
747 * @brief Clearing format flags.
748 * @param __mask The flags to unset.
749 *
750 * This function clears @a __mask in the format flags.
751 */
752 void
753 unsetf(fmtflags __mask)
754 { _M_flags &= ~__mask; }
755
756 /**
757 * @brief Flags access.
758 * @return The precision to generate on certain output operations.
759 *
760 * Be careful if you try to give a definition of @a precision here; see
761 * DR 189.
762 */
763 _GLIBCXX_NODISCARD
764 streamsize
765 precision() const
766 { return _M_precision; }
767
768 /**
769 * @brief Changing flags.
770 * @param __prec The new precision value.
771 * @return The previous value of precision().
772 */
773 streamsize
774 precision(streamsize __prec)
775 {
776 streamsize __old = _M_precision;
777 _M_precision = __prec;
778 return __old;
779 }
780
781 /**
782 * @brief Flags access.
783 * @return The minimum field width to generate on output operations.
784 *
785 * <em>Minimum field width</em> refers to the number of characters.
786 */
787 _GLIBCXX_NODISCARD
788 streamsize
789 width() const
790 { return _M_width; }
791
792 /**
793 * @brief Changing flags.
794 * @param __wide The new width value.
795 * @return The previous value of width().
796 */
797 streamsize
798 width(streamsize __wide)
799 {
800 streamsize __old = _M_width;
801 _M_width = __wide;
802 return __old;
803 }
804
805 // [27.4.2.4] ios_base static members
806 /**
807 * @brief Interaction with the standard C I/O objects.
808 * @param __sync Whether to synchronize or not.
809 * @return True if the standard streams were previously synchronized.
810 *
811 * The synchronization referred to is @e only that between the standard
812 * C facilities (e.g., stdout) and the standard C++ objects (e.g.,
813 * cout). User-declared streams are unaffected. See
814 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
815 */
816 static bool
817 sync_with_stdio(bool __sync = true);
818
819 // [27.4.2.3] ios_base locale functions
820 /**
821 * @brief Setting a new locale.
822 * @param __loc The new locale.
823 * @return The previous locale.
824 *
825 * Sets the new locale for this stream, and then invokes each callback
826 * with imbue_event.
827 */
828 locale
829 imbue(const locale& __loc) throw();
830
831 /**
832 * @brief Locale access
833 * @return A copy of the current locale.
834 *
835 * If @c imbue(loc) has previously been called, then this function
836 * returns @c loc. Otherwise, it returns a copy of @c std::locale(),
837 * the global C++ locale.
838 */
839 _GLIBCXX_NODISCARD
840 locale
841 getloc() const
842 { return _M_ios_locale; }
843
844 /**
845 * @brief Locale access
846 * @return A reference to the current locale.
847 *
848 * Like getloc above, but returns a reference instead of
849 * generating a copy.
850 */
851 const locale&
852 _M_getloc() const
853 { return _M_ios_locale; }
854
855 // [27.4.2.5] ios_base storage functions
856 /**
857 * @brief Access to unique indices.
858 * @return An integer different from all previous calls.
859 *
860 * This function returns a unique integer every time it is called. It
861 * can be used for any purpose, but is primarily intended to be a unique
862 * index for the iword and pword functions. The expectation is that an
863 * application calls xalloc in order to obtain an index in the iword and
864 * pword arrays that can be used without fear of conflict.
865 *
866 * The implementation maintains a static variable that is incremented and
867 * returned on each invocation. xalloc is guaranteed to return an index
868 * that is safe to use in the iword and pword arrays.
869 */
870 static int
871 xalloc() throw();
872
873 /**
874 * @brief Access to integer array.
875 * @param __ix Index into the array.
876 * @return A reference to an integer associated with the index.
877 *
878 * The iword function provides access to an array of integers that can be
879 * used for any purpose. The array grows as required to hold the
880 * supplied index. All integers in the array are initialized to 0.
881 *
882 * The implementation reserves several indices. You should use xalloc to
883 * obtain an index that is safe to use. Also note that since the array
884 * can grow dynamically, it is not safe to hold onto the reference.
885 */
886 long&
887 iword(int __ix)
888 {
889 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size)
890 ? _M_word[__ix] : _M_grow_words(__ix, true);
891 return __word._M_iword;
892 }
893
894 /**
895 * @brief Access to void pointer array.
896 * @param __ix Index into the array.
897 * @return A reference to a void* associated with the index.
898 *
899 * The pword function provides access to an array of pointers that can be
900 * used for any purpose. The array grows as required to hold the
901 * supplied index. All pointers in the array are initialized to 0.
902 *
903 * The implementation reserves several indices. You should use xalloc to
904 * obtain an index that is safe to use. Also note that since the array
905 * can grow dynamically, it is not safe to hold onto the reference.
906 */
907 void*&
908 pword(int __ix)
909 {
910 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size)
911 ? _M_word[__ix] : _M_grow_words(__ix, false);
912 return __word._M_pword;
913 }
914
915 // Destructor
916 /**
917 * Invokes each callback with erase_event. Destroys local storage.
918 *
919 * Note that the ios_base object for the standard streams never gets
920 * destroyed. As a result, any callbacks registered with the standard
921 * streams will not get invoked with erase_event (unless copyfmt is
922 * used).
923 */
924 virtual ~ios_base();
925
926 protected:
927 ios_base() throw ();
928
929#if __cplusplus < 201103L
930 // _GLIBCXX_RESOLVE_LIB_DEFECTS
931 // 50. Copy constructor and assignment operator of ios_base
932 private:
933 ios_base(const ios_base&);
934
935 ios_base&
936 operator=(const ios_base&);
937#else
938 public:
939 ios_base(const ios_base&) = delete;
940
941 ios_base&
942 operator=(const ios_base&) = delete;
943
944 protected:
945 void
946 _M_move(ios_base&) noexcept;
947
948 void
949 _M_swap(ios_base& __rhs) noexcept;
950#endif
951 };
952
953 // [27.4.5.1] fmtflags manipulators
954 /// Calls base.setf(ios_base::boolalpha).
955 inline ios_base&
956 boolalpha(ios_base& __base)
957 {
958 __base.setf(ios_base::boolalpha);
959 return __base;
960 }
961
962 /// Calls base.unsetf(ios_base::boolalpha).
963 inline ios_base&
964 noboolalpha(ios_base& __base)
965 {
966 __base.unsetf(ios_base::boolalpha);
967 return __base;
968 }
969
970 /// Calls base.setf(ios_base::showbase).
971 inline ios_base&
972 showbase(ios_base& __base)
973 {
974 __base.setf(ios_base::showbase);
975 return __base;
976 }
977
978 /// Calls base.unsetf(ios_base::showbase).
979 inline ios_base&
980 noshowbase(ios_base& __base)
981 {
982 __base.unsetf(ios_base::showbase);
983 return __base;
984 }
985
986 /// Calls base.setf(ios_base::showpoint).
987 inline ios_base&
988 showpoint(ios_base& __base)
989 {
990 __base.setf(ios_base::showpoint);
991 return __base;
992 }
993
994 /// Calls base.unsetf(ios_base::showpoint).
995 inline ios_base&
996 noshowpoint(ios_base& __base)
997 {
998 __base.unsetf(ios_base::showpoint);
999 return __base;
1000 }
1001
1002 /// Calls base.setf(ios_base::showpos).
1003 inline ios_base&
1004 showpos(ios_base& __base)
1005 {
1006 __base.setf(ios_base::showpos);
1007 return __base;
1008 }
1009
1010 /// Calls base.unsetf(ios_base::showpos).
1011 inline ios_base&
1012 noshowpos(ios_base& __base)
1013 {
1014 __base.unsetf(ios_base::showpos);
1015 return __base;
1016 }
1017
1018 /// Calls base.setf(ios_base::skipws).
1019 inline ios_base&
1020 skipws(ios_base& __base)
1021 {
1022 __base.setf(ios_base::skipws);
1023 return __base;
1024 }
1025
1026 /// Calls base.unsetf(ios_base::skipws).
1027 inline ios_base&
1028 noskipws(ios_base& __base)
1029 {
1030 __base.unsetf(ios_base::skipws);
1031 return __base;
1032 }
1033
1034 /// Calls base.setf(ios_base::uppercase).
1035 inline ios_base&
1036 uppercase(ios_base& __base)
1037 {
1038 __base.setf(ios_base::uppercase);
1039 return __base;
1040 }
1041
1042 /// Calls base.unsetf(ios_base::uppercase).
1043 inline ios_base&
1044 nouppercase(ios_base& __base)
1045 {
1046 __base.unsetf(ios_base::uppercase);
1047 return __base;
1048 }
1049
1050 /// Calls base.setf(ios_base::unitbuf).
1051 inline ios_base&
1052 unitbuf(ios_base& __base)
1053 {
1054 __base.setf(ios_base::unitbuf);
1055 return __base;
1056 }
1057
1058 /// Calls base.unsetf(ios_base::unitbuf).
1059 inline ios_base&
1060 nounitbuf(ios_base& __base)
1061 {
1062 __base.unsetf(ios_base::unitbuf);
1063 return __base;
1064 }
1065
1066 // [27.4.5.2] adjustfield manipulators
1067 /// Calls base.setf(ios_base::internal, ios_base::adjustfield).
1068 inline ios_base&
1069 internal(ios_base& __base)
1070 {
1071 __base.setf(ios_base::internal, ios_base::adjustfield);
1072 return __base;
1073 }
1074
1075 /// Calls base.setf(ios_base::left, ios_base::adjustfield).
1076 inline ios_base&
1077 left(ios_base& __base)
1078 {
1079 __base.setf(ios_base::left, ios_base::adjustfield);
1080 return __base;
1081 }
1082
1083 /// Calls base.setf(ios_base::right, ios_base::adjustfield).
1084 inline ios_base&
1085 right(ios_base& __base)
1086 {
1087 __base.setf(ios_base::right, ios_base::adjustfield);
1088 return __base;
1089 }
1090
1091 // [27.4.5.3] basefield manipulators
1092 /// Calls base.setf(ios_base::dec, ios_base::basefield).
1093 inline ios_base&
1094 dec(ios_base& __base)
1095 {
1096 __base.setf(ios_base::dec, ios_base::basefield);
1097 return __base;
1098 }
1099
1100 /// Calls base.setf(ios_base::hex, ios_base::basefield).
1101 inline ios_base&
1102 hex(ios_base& __base)
1103 {
1104 __base.setf(ios_base::hex, ios_base::basefield);
1105 return __base;
1106 }
1107
1108 /// Calls base.setf(ios_base::oct, ios_base::basefield).
1109 inline ios_base&
1110 oct(ios_base& __base)
1111 {
1112 __base.setf(ios_base::oct, ios_base::basefield);
1113 return __base;
1114 }
1115
1116 // [27.4.5.4] floatfield manipulators
1117 /// Calls base.setf(ios_base::fixed, ios_base::floatfield).
1118 inline ios_base&
1119 fixed(ios_base& __base)
1120 {
1121 __base.setf(ios_base::fixed, ios_base::floatfield);
1122 return __base;
1123 }
1124
1125 /// Calls base.setf(ios_base::scientific, ios_base::floatfield).
1126 inline ios_base&
1127 scientific(ios_base& __base)
1128 {
1129 __base.setf(ios_base::scientific, ios_base::floatfield);
1130 return __base;
1131 }
1132
1133#if __cplusplus >= 201103L
1134 // New C++11 floatfield manipulators
1135
1136 /// Calls
1137 /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield)
1138 inline ios_base&
1139 hexfloat(ios_base& __base)
1140 {
1141 __base.setf(ios_base::fixed | ios_base::scientific, ios_base::floatfield);
1142 return __base;
1143 }
1144
1145 /// Calls @c base.unsetf(ios_base::floatfield)
1146 inline ios_base&
1147 defaultfloat(ios_base& __base)
1148 {
1149 __base.unsetf(ios_base::floatfield);
1150 return __base;
1151 }
1152#endif
1153
1154_GLIBCXX_END_NAMESPACE_VERSION
1155} // namespace
1156
1157#endif /* _IOS_BASE_H */
stdexcept
system_error
locale_classes.h
localefwd.h
atomicity.h
std::make_error_condition
error_condition make_error_condition(future_errc __errc) noexcept
Overload of make_error_condition for future_errc.
Definition future:103
std::make_error_code
error_code make_error_code(future_errc __errc) noexcept
Overload of make_error_code for future_errc.
Definition future:97
std
ISO C++ entities toplevel namespace is std.
std::noskipws
ios_base & noskipws(ios_base &__base)
Calls base.unsetf(ios_base::skipws).
Definition ios_base.h:1028
std::streamsize
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition postypes.h:73
std::noshowpoint
ios_base & noshowpoint(ios_base &__base)
Calls base.unsetf(ios_base::showpoint).
Definition ios_base.h:996
std::nounitbuf
ios_base & nounitbuf(ios_base &__base)
Calls base.unsetf(ios_base::unitbuf).
Definition ios_base.h:1060
std::streamoff
long long streamoff
Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
Definition postypes.h:68
std::streampos
fpos< mbstate_t > streampos
File position for char streams.
Definition postypes.h:209
std::io_errc
io_errc
I/O error code.
Definition ios_base.h:236
std::noshowpos
ios_base & noshowpos(ios_base &__base)
Calls base.unsetf(ios_base::showpos).
Definition ios_base.h:1012
std::nouppercase
ios_base & nouppercase(ios_base &__base)
Calls base.unsetf(ios_base::uppercase).
Definition ios_base.h:1044
std::noshowbase
ios_base & noshowbase(ios_base &__base)
Calls base.unsetf(ios_base::showbase).
Definition ios_base.h:980
std::operator^
constexpr bitset< _Nb > operator^(const bitset< _Nb > &__x, const bitset< _Nb > &__y) noexcept
Global bitwise operations on bitsets.
Definition bitset:1638
std::hexfloat
ios_base & hexfloat(ios_base &__base)
Calls base.setf(ios_base::fixed|ios_basescientific, ios_base::floatfield)
Definition ios_base.h:1139
std::defaultfloat
ios_base & defaultfloat(ios_base &__base)
Calls base.unsetf(ios_base::floatfield)
Definition ios_base.h:1147
std::operator|
constexpr bitset< _Nb > operator|(const bitset< _Nb > &__x, const bitset< _Nb > &__y) noexcept
Global bitwise operations on bitsets.
Definition bitset:1628
std::noboolalpha
ios_base & noboolalpha(ios_base &__base)
Calls base.unsetf(ios_base::boolalpha).
Definition ios_base.h:964
std::operator&
constexpr bitset< _Nb > operator&(const bitset< _Nb > &__x, const bitset< _Nb > &__y) noexcept
Global bitwise operations on bitsets.
Definition bitset:1618
std::error_category
Definition system_error:109
std::error_code
Definition system_error:226
std::error_condition
Definition system_error:357
std::system_error
An exception type that includes an error_code value.
Definition system_error:559
std::ios_base
The base of the I/O class hierarchy.
Definition ios_base.h:266
std::ios_base::setf
fmtflags setf(fmtflags __fmtfl)
Setting new format flags.
Definition ios_base.h:721
std::ios_base::skipws
static const fmtflags skipws
Skips leading white space before certain input operations.
Definition ios_base.h:423
std::ios_base::fmtflags
_Ios_Fmtflags fmtflags
This is a bitmask type.
Definition ios_base.h:378
std::ios_base::iostate
_Ios_Iostate iostate
This is a bitmask type.
Definition ios_base.h:453
std::ios_base::hex
static const fmtflags hex
Converts integer input or generates integer output in hexadecimal base.
Definition ios_base.h:390
std::ios_base::right
static const fmtflags right
Adds fill characters on the left (initial positions) of certain generated output. (I....
Definition ios_base.h:406
std::ios_base::cur
static const seekdir cur
Request a seek relative to the current position within the sequence.
Definition ios_base.h:529
std::ios_base::uppercase
static const fmtflags uppercase
Replaces certain lowercase letters with their uppercase equivalents in generated output.
Definition ios_base.h:430
std::ios_base::basefield
static const fmtflags basefield
A mask of dec|oct|hex. Useful for the 2-arg form of setf.
Definition ios_base.h:436
std::ios_base::pword
void *& pword(int __ix)
Access to void pointer array.
Definition ios_base.h:908
std::ios_base::beg
static const seekdir beg
Request a seek relative to the beginning of the stream.
Definition ios_base.h:526
std::ios_base::precision
streamsize precision() const
Flags access.
Definition ios_base.h:765
std::ios_base::imbue
locale imbue(const locale &__loc)
Setting a new locale.
std::ios_base::dec
static const fmtflags dec
Converts integer input or generates integer output in decimal base.
Definition ios_base.h:384
std::ios_base::xalloc
static int xalloc()
Access to unique indices.
std::ios_base::flags
fmtflags flags(fmtflags __fmtfl)
Setting new format flags all at once.
Definition ios_base.h:705
std::ios_base::unsetf
void unsetf(fmtflags __mask)
Clearing format flags.
Definition ios_base.h:753
std::ios_base::showpoint
static const fmtflags showpoint
Generates a decimal-point character unconditionally in generated floating-point output.
Definition ios_base.h:417
std::ios_base::end
static const seekdir end
Request a seek relative to the current end of the sequence.
Definition ios_base.h:532
std::ios_base::register_callback
void register_callback(event_callback __fn, int __index)
Add the callback __fn with parameter __index.
std::ios_base::in
static const openmode in
Open for input. Default for ifstream and fstream.
Definition ios_base.h:498
std::ios_base::showbase
static const fmtflags showbase
Generates a prefix indicating the numeric base of generated integer output.
Definition ios_base.h:413
std::ios_base::event_callback
void(* event_callback)(event __e, ios_base &__b, int __i)
The type of an event callback function.
Definition ios_base.h:573
std::ios_base::internal
static const fmtflags internal
Adds fill characters at a designated internal point in certain generated output, or identical to righ...
Definition ios_base.h:395
std::ios_base::iword
long & iword(int __ix)
Access to integer array.
Definition ios_base.h:887
std::ios_base::out
static const openmode out
Open for output. Default for ofstream and fstream.
Definition ios_base.h:501
std::ios_base::boolalpha
static const fmtflags boolalpha
Insert/extract bool in alphabetic rather than numeric format.
Definition ios_base.h:381
std::ios_base::~ios_base
virtual ~ios_base()
std::ios_base::flags
fmtflags flags() const
Access to format flags.
Definition ios_base.h:694
std::ios_base::eofbit
static const iostate eofbit
Indicates that an input operation reached the end of an input sequence.
Definition ios_base.h:460
std::ios_base::floatfield
static const fmtflags floatfield
A mask of scientific|fixed. Useful for the 2-arg form of setf.
Definition ios_base.h:439
std::ios_base::setf
fmtflags setf(fmtflags __fmtfl, fmtflags __mask)
Setting new format flags.
Definition ios_base.h:738
std::ios_base::binary
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:495
std::ios_base::goodbit
static const iostate goodbit
Indicates all is well.
Definition ios_base.h:468
std::ios_base::_M_getloc
const locale & _M_getloc() const
Locale access.
Definition ios_base.h:852
std::ios_base::unitbuf
static const fmtflags unitbuf
Flushes output after each output operation.
Definition ios_base.h:426
std::ios_base::badbit
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:457
std::ios_base::openmode
_Ios_Openmode openmode
This is a bitmask type.
Definition ios_base.h:484
std::ios_base::width
streamsize width() const
Flags access.
Definition ios_base.h:789
std::ios_base::sync_with_stdio
static bool sync_with_stdio(bool __sync=true)
Interaction with the standard C I/O objects.
std::ios_base::fixed
static const fmtflags fixed
Generate floating-point output in fixed-point notation.
Definition ios_base.h:387
std::ios_base::oct
static const fmtflags oct
Converts integer input or generates integer output in octal base.
Definition ios_base.h:402
std::ios_base::app
static const openmode app
Seek to end before each write.
Definition ios_base.h:487
std::ios_base::seekdir
_Ios_Seekdir seekdir
This is an enumerated type.
Definition ios_base.h:523
std::ios_base::width
streamsize width(streamsize __wide)
Changing flags.
Definition ios_base.h:798
std::ios_base::left
static const fmtflags left
Adds fill characters on the right (final positions) of certain generated output. (I....
Definition ios_base.h:399
std::ios_base::showpos
static const fmtflags showpos
Generates a + sign in non-negative generated numeric output.
Definition ios_base.h:420
std::ios_base::ate
static const openmode ate
Open and seek to end immediately after opening.
Definition ios_base.h:490
std::ios_base::getloc
locale getloc() const
Locale access.
Definition ios_base.h:841
std::ios_base::trunc
static const openmode trunc
Truncate an existing stream when opening. Default for ofstream.
Definition ios_base.h:504
std::ios_base::precision
streamsize precision(streamsize __prec)
Changing flags.
Definition ios_base.h:774
std::ios_base::failbit
static const iostate failbit
Indicates that an input operation failed to read the expected characters, or that an output operation...
Definition ios_base.h:465
std::ios_base::scientific
static const fmtflags scientific
Generates floating-point output in scientific notation.
Definition ios_base.h:409
std::ios_base::adjustfield
static const fmtflags adjustfield
A mask of left|right|internal. Useful for the 2-arg form of setf.
Definition ios_base.h:433
std::ios_base::failure::what
virtual const char * what() const
std::locale
Container class for localization functionality.
Definition locale_classes.h:70
std::runtime_error
One of two subclasses of exception.
Definition stdexcept_except.h:454