1// Iostreams base classes -*- C++ -*- 
2 
3// Copyright (C) 1997-2021 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 
49namespace 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 inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags 
83 operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b) 
84 { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); } 
85 
86 inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags 
87 operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b) 
88 { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); } 
89 
90 inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags 
91 operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) 
92 { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); } 
93 
94 inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags 
95 operator~(_Ios_Fmtflags __a) 
96 { return _Ios_Fmtflags(~static_cast<int>(__a)); } 
97 
98 inline const _Ios_Fmtflags& 
99 operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) 
100 { return __a = __a | __b; } 
101 
102 inline const _Ios_Fmtflags& 
103 operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) 
104 { return __a = __a & __b; } 
105 
106 inline const _Ios_Fmtflags& 
107 operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) 
108 { return __a = __a ^ __b; } 
109 
110 
111 enum _Ios_Openmode  
112 {  
113 _S_app = 1L << 0, 
114 _S_ate = 1L << 1, 
115 _S_bin = 1L << 2, 
116 _S_in = 1L << 3, 
117 _S_out = 1L << 4, 
118 _S_trunc = 1L << 5, 
119 _S_ios_openmode_end = 1L << 16, 
120 _S_ios_openmode_max = __INT_MAX__, 
121 _S_ios_openmode_min = ~__INT_MAX__ 
122 }; 
123 
124 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 
125 operator&(_Ios_Openmode __a, _Ios_Openmode __b) 
126 { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); } 
127 
128 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 
129 operator|(_Ios_Openmode __a, _Ios_Openmode __b) 
130 { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); } 
131 
132 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 
133 operator^(_Ios_Openmode __a, _Ios_Openmode __b) 
134 { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); } 
135 
136 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 
137 operator~(_Ios_Openmode __a) 
138 { return _Ios_Openmode(~static_cast<int>(__a)); } 
139 
140 inline const _Ios_Openmode& 
141 operator|=(_Ios_Openmode& __a, _Ios_Openmode __b) 
142 { return __a = __a | __b; } 
143 
144 inline const _Ios_Openmode& 
145 operator&=(_Ios_Openmode& __a, _Ios_Openmode __b) 
146 { return __a = __a & __b; } 
147 
148 inline const _Ios_Openmode& 
149 operator^=(_Ios_Openmode& __a, _Ios_Openmode __b) 
150 { return __a = __a ^ __b; } 
151 
152 
153 enum _Ios_Iostate 
154 {  
155 _S_goodbit = 0, 
156 _S_badbit = 1L << 0, 
157 _S_eofbit = 1L << 1, 
158 _S_failbit = 1L << 2, 
159 _S_ios_iostate_end = 1L << 16, 
160 _S_ios_iostate_max = __INT_MAX__, 
161 _S_ios_iostate_min = ~__INT_MAX__ 
162 }; 
163 
164 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 
165 operator&(_Ios_Iostate __a, _Ios_Iostate __b) 
166 { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); } 
167 
168 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 
169 operator|(_Ios_Iostate __a, _Ios_Iostate __b) 
170 { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); } 
171 
172 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 
173 operator^(_Ios_Iostate __a, _Ios_Iostate __b) 
174 { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); } 
175 
176 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 
177 operator~(_Ios_Iostate __a) 
178 { return _Ios_Iostate(~static_cast<int>(__a)); } 
179 
180 inline const _Ios_Iostate& 
181 operator|=(_Ios_Iostate& __a, _Ios_Iostate __b) 
182 { return __a = __a | __b; } 
183 
184 inline const _Ios_Iostate& 
185 operator&=(_Ios_Iostate& __a, _Ios_Iostate __b) 
186 { return __a = __a & __b; } 
187 
188 inline const _Ios_Iostate& 
189 operator^=(_Ios_Iostate& __a, _Ios_Iostate __b) 
190 { return __a = __a ^ __b; } 
191 
192 
193 enum _Ios_Seekdir  
194 {  
195 _S_beg = 0, 
196 _S_cur = _GLIBCXX_STDIO_SEEK_CUR, 
197 _S_end = _GLIBCXX_STDIO_SEEK_END, 
198 _S_ios_seekdir_end = 1L << 16  
199 }; 
200 
201#if __cplusplus >= 201103L 
202 /// I/O error code 
203 enum class io_errc { stream = 1 }; 
204 
205 template <> struct is_error_code_enum<io_errc> : public true_type { }; 
206 
207 const error_category& iostream_category() noexcept; 
208 
209 inline error_code 
210 make_error_code(io_errc __e) noexcept 
211 { return error_code(static_cast<int>(__e), iostream_category()); } 
212 
213 inline error_condition 
214 make_error_condition(io_errc __e) noexcept 
215 { return error_condition(static_cast<int>(__e), iostream_category()); } 
216#endif 
217 
218 // 27.4.2 Class ios_base 
219 /** 
220 * @brief The base of the I/O class hierarchy. 
221 * @ingroup io 
222 * 
223 * This class defines everything that can be defined about I/O that does 
224 * not depend on the type of characters being input or output. Most 
225 * people will only see @c ios_base when they need to specify the full 
226 * name of the various I/O flags (e.g., the openmodes). 
227 */ 
228 class ios_base 
229 { 
230#if _GLIBCXX_USE_CXX11_ABI 
231#if __cplusplus < 201103L 
232 // Type that is layout-compatible with std::system_error 
233 struct system_error : std::runtime_error 
234 { 
235 // Type that is layout-compatible with std::error_code 
236 struct error_code 
237 { 
238 error_code() { } 
239 private: 
240 int _M_value; 
241 const void* _M_cat; 
242 } _M_code; 
243 }; 
244#endif 
245#endif 
246 public: 
247 
248 /**  
249 * @brief These are thrown to indicate problems with io. 
250 * @ingroup exceptions 
251 * 
252 * 27.4.2.1.1 Class ios_base::failure 
253 */ 
254#if _GLIBCXX_USE_CXX11_ABI 
255 class _GLIBCXX_ABI_TAG_CXX11 failure : public system_error 
256 { 
257 public: 
258 explicit 
259 failure(const string& __str); 
260 
261#if __cplusplus >= 201103L 
262 explicit 
263 failure(const string&, const error_code&); 
264 
265 explicit 
266 failure(const char*, const error_code& = io_errc::stream); 
267#endif 
268 
269 virtual 
270 ~failure() throw(); 
271 
272 virtual const char* 
273 what() const throw(); 
274 }; 
275#else 
276 class failure : public exception 
277 { 
278 public: 
279 // _GLIBCXX_RESOLVE_LIB_DEFECTS 
280 // 48. Use of non-existent exception constructor 
281 explicit 
282 failure(const string& __str) throw(); 
283 
284 // This declaration is not useless: 
285 // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html 
286 virtual 
287 ~failure() throw(); 
288 
289 virtual const char* 
290 what() const throw(); 
291 
292#if __cplusplus >= 201103L 
293 // Define the new members required by C++11, 
294 // even though the error_code cannot be stored. 
295 
296 explicit 
297 failure(const string& __s, const error_code&) noexcept 
298 : failure(__s) 
299 { } 
300 
301 explicit 
302 failure(const char* __s, const error_code& = error_code{}) 
303 : failure(string(__s)) 
304 { } 
305 
306 // Stand-in for system_error::code() but returning by value. 
307 error_code code() const noexcept { return error_code{}; } 
308#endif 
309 
310 private: 
311 string _M_msg; 
312 }; 
313#endif 
314 
315 // 27.4.2.1.2 Type ios_base::fmtflags 
316 /** 
317 * @brief This is a bitmask type. 
318 * 
319 * @c @a _Ios_Fmtflags is implementation-defined, but it is valid to 
320 * perform bitwise operations on these values and expect the Right 
321 * Thing to happen. Defined objects of type fmtflags are: 
322 * - boolalpha 
323 * - dec 
324 * - fixed 
325 * - hex 
326 * - internal 
327 * - left 
328 * - oct 
329 * - right 
330 * - scientific 
331 * - showbase 
332 * - showpoint 
333 * - showpos 
334 * - skipws 
335 * - unitbuf 
336 * - uppercase 
337 * - adjustfield 
338 * - basefield 
339 * - floatfield 
340 */ 
341 typedef _Ios_Fmtflags fmtflags; 
342 
343 /// Insert/extract @c bool in alphabetic rather than numeric format. 
344 static const fmtflags boolalpha = _S_boolalpha; 
345 
346 /// Converts integer input or generates integer output in decimal base. 
347 static const fmtflags dec = _S_dec; 
348 
349 /// Generate floating-point output in fixed-point notation. 
350 static const fmtflags fixed = _S_fixed; 
351 
352 /// Converts integer input or generates integer output in hexadecimal base. 
353 static const fmtflags hex = _S_hex; 
354 
355 /// Adds fill characters at a designated internal point in certain 
356 /// generated output, or identical to @c right if no such point is 
357 /// designated. 
358 static const fmtflags internal = _S_internal; 
359 
360 /// Adds fill characters on the right (final positions) of certain 
361 /// generated output. (I.e., the thing you print is flush left.) 
362 static const fmtflags left = _S_left; 
363 
364 /// Converts integer input or generates integer output in octal base. 
365 static const fmtflags oct = _S_oct; 
366 
367 /// Adds fill characters on the left (initial positions) of certain 
368 /// generated output. (I.e., the thing you print is flush right.) 
369 static const fmtflags right = _S_right; 
370 
371 /// Generates floating-point output in scientific notation. 
372 static const fmtflags scientific = _S_scientific; 
373 
374 /// Generates a prefix indicating the numeric base of generated integer 
375 /// output. 
376 static const fmtflags showbase = _S_showbase; 
377 
378 /// Generates a decimal-point character unconditionally in generated 
379 /// floating-point output. 
380 static const fmtflags showpoint = _S_showpoint; 
381 
382 /// Generates a + sign in non-negative generated numeric output. 
383 static const fmtflags showpos = _S_showpos; 
384 
385 /// Skips leading white space before certain input operations. 
386 static const fmtflags skipws = _S_skipws; 
387 
388 /// Flushes output after each output operation. 
389 static const fmtflags unitbuf = _S_unitbuf; 
390 
391 /// Replaces certain lowercase letters with their uppercase equivalents 
392 /// in generated output. 
393 static const fmtflags uppercase = _S_uppercase; 
394 
395 /// A mask of left|right|internal. Useful for the 2-arg form of @c setf. 
396 static const fmtflags adjustfield = _S_adjustfield; 
397 
398 /// A mask of dec|oct|hex. Useful for the 2-arg form of @c setf. 
399 static const fmtflags basefield = _S_basefield; 
400 
401 /// A mask of scientific|fixed. Useful for the 2-arg form of @c setf. 
402 static const fmtflags floatfield = _S_floatfield; 
403 
404 // 27.4.2.1.3 Type ios_base::iostate 
405 /** 
406 * @brief This is a bitmask type. 
407 * 
408 * @c @a _Ios_Iostate is implementation-defined, but it is valid to 
409 * perform bitwise operations on these values and expect the Right 
410 * Thing to happen. Defined objects of type iostate are: 
411 * - badbit 
412 * - eofbit 
413 * - failbit 
414 * - goodbit 
415 */ 
416 typedef _Ios_Iostate iostate; 
417 
418 /// Indicates a loss of integrity in an input or output sequence (such 
419 /// as an irrecoverable read error from a file). 
420 static const iostate badbit = _S_badbit; 
421 
422 /// Indicates that an input operation reached the end of an input sequence. 
423 static const iostate eofbit = _S_eofbit; 
424 
425 /// Indicates that an input operation failed to read the expected 
426 /// characters, or that an output operation failed to generate the 
427 /// desired characters. 
428 static const iostate failbit = _S_failbit; 
429 
430 /// Indicates all is well. 
431 static const iostate goodbit = _S_goodbit; 
432 
433 // 27.4.2.1.4 Type ios_base::openmode 
434 /** 
435 * @brief This is a bitmask type. 
436 * 
437 * @c @a _Ios_Openmode is implementation-defined, but it is valid to 
438 * perform bitwise operations on these values and expect the Right 
439 * Thing to happen. Defined objects of type openmode are: 
440 * - app 
441 * - ate 
442 * - binary 
443 * - in 
444 * - out 
445 * - trunc 
446 */ 
447 typedef _Ios_Openmode openmode; 
448 
449 /// Seek to end before each write. 
450 static const openmode app = _S_app; 
451 
452 /// Open and seek to end immediately after opening. 
453 static const openmode ate = _S_ate; 
454 
455 /// Perform input and output in binary mode (as opposed to text mode). 
456 /// This is probably not what you think it is; see 
457 /// https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 
458 static const openmode binary = _S_bin; 
459 
460 /// Open for input. Default for @c ifstream and fstream. 
461 static const openmode in = _S_in; 
462 
463 /// Open for output. Default for @c ofstream and fstream. 
464 static const openmode out = _S_out; 
465 
466 /// Truncate an existing stream when opening. Default for @c ofstream. 
467 static const openmode trunc = _S_trunc; 
468 
469 // 27.4.2.1.5 Type ios_base::seekdir 
470 /** 
471 * @brief This is an enumerated type. 
472 * 
473 * @c @a _Ios_Seekdir is implementation-defined. Defined values 
474 * of type seekdir are: 
475 * - beg 
476 * - cur, equivalent to @c SEEK_CUR in the C standard library. 
477 * - end, equivalent to @c SEEK_END in the C standard library. 
478 */ 
479 typedef _Ios_Seekdir seekdir; 
480 
481 /// Request a seek relative to the beginning of the stream. 
482 static const seekdir beg = _S_beg; 
483 
484 /// Request a seek relative to the current position within the sequence. 
485 static const seekdir cur = _S_cur; 
486 
487 /// Request a seek relative to the current end of the sequence. 
488 static const seekdir end = _S_end; 
489 
490#if __cplusplus <= 201402L 
491 // Annex D.6 (removed in C++17) 
492 typedef int io_state 
493 _GLIBCXX_DEPRECATED_SUGGEST("std::iostate"); 
494 typedef int open_mode 
495 _GLIBCXX_DEPRECATED_SUGGEST("std::openmode"); 
496 typedef int seek_dir 
497 _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir"); 
498 
499 typedef std::streampos streampos 
500 _GLIBCXX_DEPRECATED_SUGGEST("std::streampos"); 
501 typedef std::streamoff streamoff 
502 _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff"); 
503#endif 
504 
505 // Callbacks; 
506 /** 
507 * @brief The set of events that may be passed to an event callback. 
508 * 
509 * erase_event is used during ~ios() and copyfmt(). imbue_event is used 
510 * during imbue(). copyfmt_event is used during copyfmt(). 
511 */ 
512 enum event 
513 { 
514 erase_event, 
515 imbue_event, 
516 copyfmt_event 
517 }; 
518 
519 /** 
520 * @brief The type of an event callback function. 
521 * @param __e One of the members of the event enum. 
522 * @param __b Reference to the ios_base object. 
523 * @param __i The integer provided when the callback was registered. 
524 * 
525 * Event callbacks are user defined functions that get called during 
526 * several ios_base and basic_ios functions, specifically imbue(), 
527 * copyfmt(), and ~ios(). 
528 */ 
529 typedef void (*event_callback) (event __e, ios_base& __b, int __i); 
530 
531 /** 
532 * @brief Add the callback __fn with parameter __index. 
533 * @param __fn The function to add. 
534 * @param __index The integer to pass to the function when invoked. 
535 * 
536 * Registers a function as an event callback with an integer parameter to 
537 * be passed to the function when invoked. Multiple copies of the 
538 * function are allowed. If there are multiple callbacks, they are 
539 * invoked in the order they were registered. 
540 */ 
541 void 
542 register_callback(event_callback __fn, int __index); 
543 
544 protected: 
545 streamsize _M_precision; 
546 streamsize _M_width; 
547 fmtflags _M_flags; 
548 iostate _M_exception; 
549 iostate _M_streambuf_state; 
550 
551 // 27.4.2.6 Members for callbacks 
552 // 27.4.2.6 ios_base callbacks 
553 struct _Callback_list 
554 { 
555 // Data Members 
556 _Callback_list* _M_next; 
557 ios_base::event_callback _M_fn; 
558 int _M_index; 
559 _Atomic_word _M_refcount; // 0 means one reference. 
560 
561 _Callback_list(ios_base::event_callback __fn, int __index, 
562 _Callback_list* __cb) 
563 : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { } 
564 
565 void 
566 _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(mem: &_M_refcount, val: 1); } 
567 
568 // 0 => OK to delete. 
569 int 
570 _M_remove_reference()  
571 { 
572 // Be race-detector-friendly. For more info see bits/c++config. 
573 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount); 
574 int __res = __gnu_cxx::__exchange_and_add_dispatch(mem: &_M_refcount, val: -1); 
575 if (__res == 0) 
576 { 
577 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount); 
578 } 
579 return __res; 
580 } 
581 }; 
582 
583 _Callback_list* _M_callbacks; 
584 
585 void 
586 _M_call_callbacks(event __ev) throw(); 
587 
588 void 
589 _M_dispose_callbacks(void) throw(); 
590 
591 // 27.4.2.5 Members for iword/pword storage 
592 struct _Words 
593 { 
594 void* _M_pword; 
595 long _M_iword; 
596 _Words() : _M_pword(0), _M_iword(0) { } 
597 }; 
598 
599 // Only for failed iword/pword calls. 
600 _Words _M_word_zero; 
601 
602 // Guaranteed storage. 
603 // The first 5 iword and pword slots are reserved for internal use. 
604 enum { _S_local_word_size = 8 }; 
605 _Words _M_local_word[_S_local_word_size]; 
606 
607 // Allocated storage. 
608 int _M_word_size; 
609 _Words* _M_word; 
610 
611 _Words& 
612 _M_grow_words(int __index, bool __iword); 
613 
614 // Members for locale and locale caching. 
615 locale _M_ios_locale; 
616 
617 void 
618 _M_init() throw(); 
619 
620 public: 
621 
622 // 27.4.2.1.6 Class ios_base::Init 
623 // Used to initialize standard streams. In theory, g++ could use 
624 // -finit-priority to order this stuff correctly without going 
625 // through these machinations. 
626 class Init 
627 { 
628 friend class ios_base; 
629 public: 
630 Init(); 
631 ~Init(); 
632 
633#if __cplusplus >= 201103L 
634 Init(const Init&) = default; 
635 Init& operator=(const Init&) = default; 
636#endif 
637 
638 private: 
639 static _Atomic_word _S_refcount; 
640 static bool _S_synced_with_stdio; 
641 }; 
642 
643 // [27.4.2.2] fmtflags state functions 
644 /** 
645 * @brief Access to format flags. 
646 * @return The format control flags for both input and output. 
647 */ 
648 fmtflags 
649 flags() const 
650 { return _M_flags; } 
651 
652 /** 
653 * @brief Setting new format flags all at once. 
654 * @param __fmtfl The new flags to set. 
655 * @return The previous format control flags. 
656 * 
657 * This function overwrites all the format flags with @a __fmtfl. 
658 */ 
659 fmtflags 
660 flags(fmtflags __fmtfl) 
661 { 
662 fmtflags __old = _M_flags; 
663 _M_flags = __fmtfl; 
664 return __old; 
665 } 
666 
667 /** 
668 * @brief Setting new format flags. 
669 * @param __fmtfl Additional flags to set. 
670 * @return The previous format control flags. 
671 * 
672 * This function sets additional flags in format control. Flags that 
673 * were previously set remain set. 
674 */ 
675 fmtflags 
676 setf(fmtflags __fmtfl) 
677 { 
678 fmtflags __old = _M_flags; 
679 _M_flags |= __fmtfl; 
680 return __old; 
681 } 
682 
683 /** 
684 * @brief Setting new format flags. 
685 * @param __fmtfl Additional flags to set. 
686 * @param __mask The flags mask for @a fmtfl. 
687 * @return The previous format control flags. 
688 * 
689 * This function clears @a mask in the format flags, then sets 
690 * @a fmtfl @c & @a mask. An example mask is @c ios_base::adjustfield. 
691 */ 
692 fmtflags 
693 setf(fmtflags __fmtfl, fmtflags __mask) 
694 { 
695 fmtflags __old = _M_flags; 
696 _M_flags &= ~__mask; 
697 _M_flags |= (__fmtfl & __mask); 
698 return __old; 
699 } 
700 
701 /** 
702 * @brief Clearing format flags. 
703 * @param __mask The flags to unset. 
704 * 
705 * This function clears @a __mask in the format flags. 
706 */ 
707 void 
708 unsetf(fmtflags __mask) 
709 { _M_flags &= ~__mask; } 
710 
711 /** 
712 * @brief Flags access. 
713 * @return The precision to generate on certain output operations. 
714 * 
715 * Be careful if you try to give a definition of @a precision here; see 
716 * DR 189. 
717 */ 
718 streamsize 
719 precision() const 
720 { return _M_precision; } 
721 
722 /** 
723 * @brief Changing flags. 
724 * @param __prec The new precision value. 
725 * @return The previous value of precision(). 
726 */ 
727 streamsize 
728 precision(streamsize __prec) 
729 { 
730 streamsize __old = _M_precision; 
731 _M_precision = __prec; 
732 return __old; 
733 } 
734 
735 /** 
736 * @brief Flags access. 
737 * @return The minimum field width to generate on output operations. 
738 * 
739 * <em>Minimum field width</em> refers to the number of characters. 
740 */ 
741 streamsize 
742 width() const 
743 { return _M_width; } 
744 
745 /** 
746 * @brief Changing flags. 
747 * @param __wide The new width value. 
748 * @return The previous value of width(). 
749 */ 
750 streamsize 
751 width(streamsize __wide) 
752 { 
753 streamsize __old = _M_width; 
754 _M_width = __wide; 
755 return __old; 
756 } 
757 
758 // [27.4.2.4] ios_base static members 
759 /** 
760 * @brief Interaction with the standard C I/O objects. 
761 * @param __sync Whether to synchronize or not. 
762 * @return True if the standard streams were previously synchronized. 
763 * 
764 * The synchronization referred to is @e only that between the standard 
765 * C facilities (e.g., stdout) and the standard C++ objects (e.g., 
766 * cout). User-declared streams are unaffected. See 
767 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 
768 */ 
769 static bool 
770 sync_with_stdio(bool __sync = true); 
771 
772 // [27.4.2.3] ios_base locale functions 
773 /** 
774 * @brief Setting a new locale. 
775 * @param __loc The new locale. 
776 * @return The previous locale. 
777 * 
778 * Sets the new locale for this stream, and then invokes each callback 
779 * with imbue_event. 
780 */ 
781 locale 
782 imbue(const locale& __loc) throw(); 
783 
784 /** 
785 * @brief Locale access 
786 * @return A copy of the current locale. 
787 * 
788 * If @c imbue(loc) has previously been called, then this function 
789 * returns @c loc. Otherwise, it returns a copy of @c std::locale(), 
790 * the global C++ locale. 
791 */ 
792 locale 
793 getloc() const 
794 { return _M_ios_locale; } 
795 
796 /** 
797 * @brief Locale access 
798 * @return A reference to the current locale. 
799 * 
800 * Like getloc above, but returns a reference instead of 
801 * generating a copy. 
802 */ 
803 const locale& 
804 _M_getloc() const 
805 { return _M_ios_locale; } 
806 
807 // [27.4.2.5] ios_base storage functions 
808 /** 
809 * @brief Access to unique indices. 
810 * @return An integer different from all previous calls. 
811 * 
812 * This function returns a unique integer every time it is called. It 
813 * can be used for any purpose, but is primarily intended to be a unique 
814 * index for the iword and pword functions. The expectation is that an 
815 * application calls xalloc in order to obtain an index in the iword and 
816 * pword arrays that can be used without fear of conflict. 
817 * 
818 * The implementation maintains a static variable that is incremented and 
819 * returned on each invocation. xalloc is guaranteed to return an index 
820 * that is safe to use in the iword and pword arrays. 
821 */ 
822 static int 
823 xalloc() throw(); 
824 
825 /** 
826 * @brief Access to integer array. 
827 * @param __ix Index into the array. 
828 * @return A reference to an integer associated with the index. 
829 * 
830 * The iword function provides access to an array of integers that can be 
831 * used for any purpose. The array grows as required to hold the 
832 * supplied index. All integers in the array are initialized to 0. 
833 * 
834 * The implementation reserves several indices. You should use xalloc to 
835 * obtain an index that is safe to use. Also note that since the array 
836 * can grow dynamically, it is not safe to hold onto the reference. 
837 */ 
838 long& 
839 iword(int __ix) 
840 { 
841 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 
842 ? _M_word[__ix] : _M_grow_words(index: __ix, iword: true); 
843 return __word._M_iword; 
844 } 
845 
846 /** 
847 * @brief Access to void pointer array. 
848 * @param __ix Index into the array. 
849 * @return A reference to a void* associated with the index. 
850 * 
851 * The pword function provides access to an array of pointers that can be 
852 * used for any purpose. The array grows as required to hold the 
853 * supplied index. All pointers in the array are initialized to 0. 
854 * 
855 * The implementation reserves several indices. You should use xalloc to 
856 * obtain an index that is safe to use. Also note that since the array 
857 * can grow dynamically, it is not safe to hold onto the reference. 
858 */ 
859 void*& 
860 pword(int __ix) 
861 { 
862 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 
863 ? _M_word[__ix] : _M_grow_words(index: __ix, iword: false); 
864 return __word._M_pword; 
865 } 
866 
867 // Destructor 
868 /** 
869 * Invokes each callback with erase_event. Destroys local storage. 
870 * 
871 * Note that the ios_base object for the standard streams never gets 
872 * destroyed. As a result, any callbacks registered with the standard 
873 * streams will not get invoked with erase_event (unless copyfmt is 
874 * used). 
875 */ 
876 virtual ~ios_base(); 
877 
878 protected: 
879 ios_base() throw (); 
880 
881#if __cplusplus < 201103L 
882 // _GLIBCXX_RESOLVE_LIB_DEFECTS 
883 // 50. Copy constructor and assignment operator of ios_base 
884 private: 
885 ios_base(const ios_base&); 
886 
887 ios_base& 
888 operator=(const ios_base&); 
889#else 
890 public: 
891 ios_base(const ios_base&) = delete; 
892 
893 ios_base& 
894 operator=(const ios_base&) = delete; 
895 
896 protected: 
897 void 
898 _M_move(ios_base&) noexcept; 
899 
900 void 
901 _M_swap(ios_base& __rhs) noexcept; 
902#endif 
903 }; 
904 
905 // [27.4.5.1] fmtflags manipulators 
906 /// Calls base.setf(ios_base::boolalpha). 
907 inline ios_base& 
908 boolalpha(ios_base& __base) 
909 { 
910 __base.setf(ios_base::boolalpha); 
911 return __base; 
912 } 
913 
914 /// Calls base.unsetf(ios_base::boolalpha). 
915 inline ios_base& 
916 noboolalpha(ios_base& __base) 
917 { 
918 __base.unsetf(mask: ios_base::boolalpha); 
919 return __base; 
920 } 
921 
922 /// Calls base.setf(ios_base::showbase). 
923 inline ios_base& 
924 showbase(ios_base& __base) 
925 { 
926 __base.setf(ios_base::showbase); 
927 return __base; 
928 } 
929 
930 /// Calls base.unsetf(ios_base::showbase). 
931 inline ios_base& 
932 noshowbase(ios_base& __base) 
933 { 
934 __base.unsetf(mask: ios_base::showbase); 
935 return __base; 
936 } 
937 
938 /// Calls base.setf(ios_base::showpoint). 
939 inline ios_base& 
940 showpoint(ios_base& __base) 
941 { 
942 __base.setf(ios_base::showpoint); 
943 return __base; 
944 } 
945 
946 /// Calls base.unsetf(ios_base::showpoint). 
947 inline ios_base& 
948 noshowpoint(ios_base& __base) 
949 { 
950 __base.unsetf(mask: ios_base::showpoint); 
951 return __base; 
952 } 
953 
954 /// Calls base.setf(ios_base::showpos). 
955 inline ios_base& 
956 showpos(ios_base& __base) 
957 { 
958 __base.setf(ios_base::showpos); 
959 return __base; 
960 } 
961 
962 /// Calls base.unsetf(ios_base::showpos). 
963 inline ios_base& 
964 noshowpos(ios_base& __base) 
965 { 
966 __base.unsetf(mask: ios_base::showpos); 
967 return __base; 
968 } 
969 
970 /// Calls base.setf(ios_base::skipws). 
971 inline ios_base& 
972 skipws(ios_base& __base) 
973 { 
974 __base.setf(ios_base::skipws); 
975 return __base; 
976 } 
977 
978 /// Calls base.unsetf(ios_base::skipws). 
979 inline ios_base& 
980 noskipws(ios_base& __base) 
981 { 
982 __base.unsetf(mask: ios_base::skipws); 
983 return __base; 
984 } 
985 
986 /// Calls base.setf(ios_base::uppercase). 
987 inline ios_base& 
988 uppercase(ios_base& __base) 
989 { 
990 __base.setf(ios_base::uppercase); 
991 return __base; 
992 } 
993 
994 /// Calls base.unsetf(ios_base::uppercase). 
995 inline ios_base& 
996 nouppercase(ios_base& __base) 
997 { 
998 __base.unsetf(mask: ios_base::uppercase); 
999 return __base; 
1000 } 
1001 
1002 /// Calls base.setf(ios_base::unitbuf). 
1003 inline ios_base& 
1004 unitbuf(ios_base& __base) 
1005 { 
1006 __base.setf(ios_base::unitbuf); 
1007 return __base; 
1008 } 
1009 
1010 /// Calls base.unsetf(ios_base::unitbuf). 
1011 inline ios_base& 
1012 nounitbuf(ios_base& __base) 
1013 { 
1014 __base.unsetf(mask: ios_base::unitbuf); 
1015 return __base; 
1016 } 
1017 
1018 // [27.4.5.2] adjustfield manipulators 
1019 /// Calls base.setf(ios_base::internal, ios_base::adjustfield). 
1020 inline ios_base& 
1021 internal(ios_base& __base) 
1022 { 
1023 __base.setf(fmtfl: ios_base::internal, mask: ios_base::adjustfield); 
1024 return __base; 
1025 } 
1026 
1027 /// Calls base.setf(ios_base::left, ios_base::adjustfield). 
1028 inline ios_base& 
1029 left(ios_base& __base) 
1030 { 
1031 __base.setf(fmtfl: ios_base::left, mask: ios_base::adjustfield); 
1032 return __base; 
1033 } 
1034 
1035 /// Calls base.setf(ios_base::right, ios_base::adjustfield). 
1036 inline ios_base& 
1037 right(ios_base& __base) 
1038 { 
1039 __base.setf(fmtfl: ios_base::right, mask: ios_base::adjustfield); 
1040 return __base; 
1041 } 
1042 
1043 // [27.4.5.3] basefield manipulators 
1044 /// Calls base.setf(ios_base::dec, ios_base::basefield). 
1045 inline ios_base& 
1046 dec(ios_base& __base) 
1047 { 
1048 __base.setf(fmtfl: ios_base::dec, mask: ios_base::basefield); 
1049 return __base; 
1050 } 
1051 
1052 /// Calls base.setf(ios_base::hex, ios_base::basefield). 
1053 inline ios_base& 
1054 hex(ios_base& __base) 
1055 { 
1056 __base.setf(fmtfl: ios_base::hex, mask: ios_base::basefield); 
1057 return __base; 
1058 } 
1059 
1060 /// Calls base.setf(ios_base::oct, ios_base::basefield). 
1061 inline ios_base& 
1062 oct(ios_base& __base) 
1063 { 
1064 __base.setf(fmtfl: ios_base::oct, mask: ios_base::basefield); 
1065 return __base; 
1066 } 
1067 
1068 // [27.4.5.4] floatfield manipulators 
1069 /// Calls base.setf(ios_base::fixed, ios_base::floatfield). 
1070 inline ios_base& 
1071 fixed(ios_base& __base) 
1072 { 
1073 __base.setf(fmtfl: ios_base::fixed, mask: ios_base::floatfield); 
1074 return __base; 
1075 } 
1076 
1077 /// Calls base.setf(ios_base::scientific, ios_base::floatfield). 
1078 inline ios_base& 
1079 scientific(ios_base& __base) 
1080 { 
1081 __base.setf(fmtfl: ios_base::scientific, mask: ios_base::floatfield); 
1082 return __base; 
1083 } 
1084 
1085#if __cplusplus >= 201103L 
1086 // New C++11 floatfield manipulators 
1087 
1088 /// Calls 
1089 /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield) 
1090 inline ios_base& 
1091 hexfloat(ios_base& __base) 
1092 { 
1093 __base.setf(fmtfl: ios_base::fixed | ios_base::scientific, mask: ios_base::floatfield); 
1094 return __base; 
1095 } 
1096 
1097 /// Calls @c base.unsetf(ios_base::floatfield) 
1098 inline ios_base& 
1099 defaultfloat(ios_base& __base) 
1100 { 
1101 __base.unsetf(mask: ios_base::floatfield); 
1102 return __base; 
1103 } 
1104#endif 
1105 
1106_GLIBCXX_END_NAMESPACE_VERSION 
1107} // namespace 
1108 
1109#endif /* _IOS_BASE_H */ 
1110