1 // Iostreams base classes -*- C++ -*- 2 3 // Copyright (C) 1997-2019 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 _GLIBCXX_VISIBILITY(default)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 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 private: 293 string _M_msg; 294 }; 295 #endif 296 297 // 27.4.2.1.2 Type ios_base::fmtflags 298 /** 299 * @brief This is a bitmask type. 300 * 301 * @c @a _Ios_Fmtflags is implementation-defined, but it is valid to 302 * perform bitwise operations on these values and expect the Right 303 * Thing to happen. Defined objects of type fmtflags are: 304 * - boolalpha 305 * - dec 306 * - fixed 307 * - hex 308 * - internal 309 * - left 310 * - oct 311 * - right 312 * - scientific 313 * - showbase 314 * - showpoint 315 * - showpos 316 * - skipws 317 * - unitbuf 318 * - uppercase 319 * - adjustfield 320 * - basefield 321 * - floatfield 322 */ 323 typedef _Ios_Fmtflags fmtflags; 324 325 /// Insert/extract @c bool in alphabetic rather than numeric format. 326 static const fmtflags boolalpha = _S_boolalpha; 327 328 /// Converts integer input or generates integer output in decimal base. 329 static const fmtflags dec = _S_dec; 330 331 /// Generate floating-point output in fixed-point notation. 332 static const fmtflags fixed = _S_fixed; 333 334 /// Converts integer input or generates integer output in hexadecimal base. 335 static const fmtflags hex = _S_hex; 336 337 /// Adds fill characters at a designated internal point in certain 338 /// generated output, or identical to @c right if no such point is 339 /// designated. 340 static const fmtflags internal = _S_internal; 341 342 /// Adds fill characters on the right (final positions) of certain 343 /// generated output. (I.e., the thing you print is flush left.) 344 static const fmtflags left = _S_left; 345 346 /// Converts integer input or generates integer output in octal base. 347 static const fmtflags oct = _S_oct; 348 349 /// Adds fill characters on the left (initial positions) of certain 350 /// generated output. (I.e., the thing you print is flush right.) 351 static const fmtflags right = _S_right; 352 353 /// Generates floating-point output in scientific notation. 354 static const fmtflags scientific = _S_scientific; 355 356 /// Generates a prefix indicating the numeric base of generated integer 357 /// output. 358 static const fmtflags showbase = _S_showbase; 359 360 /// Generates a decimal-point character unconditionally in generated 361 /// floating-point output. 362 static const fmtflags showpoint = _S_showpoint; 363 364 /// Generates a + sign in non-negative generated numeric output. 365 static const fmtflags showpos = _S_showpos; 366 367 /// Skips leading white space before certain input operations. 368 static const fmtflags skipws = _S_skipws; 369 370 /// Flushes output after each output operation. 371 static const fmtflags unitbuf = _S_unitbuf; 372 373 /// Replaces certain lowercase letters with their uppercase equivalents 374 /// in generated output. 375 static const fmtflags uppercase = _S_uppercase; 376 377 /// A mask of left|right|internal. Useful for the 2-arg form of @c setf. 378 static const fmtflags adjustfield = _S_adjustfield; 379 380 /// A mask of dec|oct|hex. Useful for the 2-arg form of @c setf. 381 static const fmtflags basefield = _S_basefield; 382 383 /// A mask of scientific|fixed. Useful for the 2-arg form of @c setf. 384 static const fmtflags floatfield = _S_floatfield; 385 386 // 27.4.2.1.3 Type ios_base::iostate 387 /** 388 * @brief This is a bitmask type. 389 * 390 * @c @a _Ios_Iostate is implementation-defined, but it is valid to 391 * perform bitwise operations on these values and expect the Right 392 * Thing to happen. Defined objects of type iostate are: 393 * - badbit 394 * - eofbit 395 * - failbit 396 * - goodbit 397 */ 398 typedef _Ios_Iostate iostate; 399 400 /// Indicates a loss of integrity in an input or output sequence (such 401 /// as an irrecoverable read error from a file). 402 static const iostate badbit = _S_badbit; 403 404 /// Indicates that an input operation reached the end of an input sequence. 405 static const iostate eofbit = _S_eofbit; 406 407 /// Indicates that an input operation failed to read the expected 408 /// characters, or that an output operation failed to generate the 409 /// desired characters. 410 static const iostate failbit = _S_failbit; 411 412 /// Indicates all is well. 413 static const iostate goodbit = _S_goodbit; 414 415 // 27.4.2.1.4 Type ios_base::openmode 416 /** 417 * @brief This is a bitmask type. 418 * 419 * @c @a _Ios_Openmode is implementation-defined, but it is valid to 420 * perform bitwise operations on these values and expect the Right 421 * Thing to happen. Defined objects of type openmode are: 422 * - app 423 * - ate 424 * - binary 425 * - in 426 * - out 427 * - trunc 428 */ 429 typedef _Ios_Openmode openmode; 430 431 /// Seek to end before each write. 432 static const openmode app = _S_app; 433 434 /// Open and seek to end immediately after opening. 435 static const openmode ate = _S_ate; 436 437 /// Perform input and output in binary mode (as opposed to text mode). 438 /// This is probably not what you think it is; see 439 /// https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 440 static const openmode binary = _S_bin; 441 442 /// Open for input. Default for @c ifstream and fstream. 443 static const openmode in = _S_in; 444 445 /// Open for output. Default for @c ofstream and fstream. 446 static const openmode out = _S_out; 447 448 /// Truncate an existing stream when opening. Default for @c ofstream. 449 static const openmode trunc = _S_trunc; 450 451 // 27.4.2.1.5 Type ios_base::seekdir 452 /** 453 * @brief This is an enumerated type. 454 * 455 * @c @a _Ios_Seekdir is implementation-defined. Defined values 456 * of type seekdir are: 457 * - beg 458 * - cur, equivalent to @c SEEK_CUR in the C standard library. 459 * - end, equivalent to @c SEEK_END in the C standard library. 460 */ 461 typedef _Ios_Seekdir seekdir; 462 463 /// Request a seek relative to the beginning of the stream. 464 static const seekdir beg = _S_beg; 465 466 /// Request a seek relative to the current position within the sequence. 467 static const seekdir cur = _S_cur; 468 469 /// Request a seek relative to the current end of the sequence. 470 static const seekdir end = _S_end; 471 472 #if __cplusplus <= 201402L 473 // Annex D.6 (removed in C++17) 474 typedef int io_state 475 _GLIBCXX_DEPRECATED_SUGGEST("std::iostate"); 476 typedef int open_mode 477 _GLIBCXX_DEPRECATED_SUGGEST("std::openmode"); 478 typedef int seek_dir 479 _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir"); 480 481 typedef std::streampos streampos 482 _GLIBCXX_DEPRECATED_SUGGEST("std::streampos"); 483 typedef std::streamoff streamoff 484 _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff"); 485 #endif 486 487 // Callbacks; 488 /** 489 * @brief The set of events that may be passed to an event callback. 490 * 491 * erase_event is used during ~ios() and copyfmt(). imbue_event is used 492 * during imbue(). copyfmt_event is used during copyfmt(). 493 */ 494 enum event 495 { 496 erase_event, 497 imbue_event, 498 copyfmt_event 499 }; 500 501 /** 502 * @brief The type of an event callback function. 503 * @param __e One of the members of the event enum. 504 * @param __b Reference to the ios_base object. 505 * @param __i The integer provided when the callback was registered. 506 * 507 * Event callbacks are user defined functions that get called during 508 * several ios_base and basic_ios functions, specifically imbue(), 509 * copyfmt(), and ~ios(). 510 */ 511 typedef void (*event_callback) (event __e, ios_base& __b, int __i); 512 513 /** 514 * @brief Add the callback __fn with parameter __index. 515 * @param __fn The function to add. 516 * @param __index The integer to pass to the function when invoked. 517 * 518 * Registers a function as an event callback with an integer parameter to 519 * be passed to the function when invoked. Multiple copies of the 520 * function are allowed. If there are multiple callbacks, they are 521 * invoked in the order they were registered. 522 */ 523 void 524 register_callback(event_callback __fn, int __index); 525 526 protected: 527 streamsize _M_precision; 528 streamsize _M_width; 529 fmtflags _M_flags; 530 iostate _M_exception; 531 iostate _M_streambuf_state; 532 533 // 27.4.2.6 Members for callbacks 534 // 27.4.2.6 ios_base callbacks 535 struct _Callback_list 536 { 537 // Data Members 538 _Callback_list* _M_next; 539 ios_base::event_callback _M_fn; 540 int _M_index; 541 _Atomic_word _M_refcount; // 0 means one reference. 542 543 _Callback_list(ios_base::event_callback __fn, int __index, 544 _Callback_list* __cb) 545 : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { } 546 547 void 548 _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); } 549 550 // 0 => OK to delete. 551 int 552 _M_remove_reference() 553 { 554 // Be race-detector-friendly. For more info see bits/c++config. 555 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount); 556 int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1); 557 if (__res == 0) 558 { 559 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount); 560 } 561 return __res; 562 } 563 }; 564 565 _Callback_list* _M_callbacks; 566 567 void 568 _M_call_callbacks(event __ev) throw(); 569 570 void 571 _M_dispose_callbacks(void) throw(); 572 573 // 27.4.2.5 Members for iword/pword storage 574 struct _Words 575 { 576 void* _M_pword; 577 long _M_iword; 578 _Words() : _M_pword(0), _M_iword(0) { } 579 }; 580 581 // Only for failed iword/pword calls. 582 _Words _M_word_zero; 583 584 // Guaranteed storage. 585 // The first 5 iword and pword slots are reserved for internal use. 586 enum { _S_local_word_size = 8 }; 587 _Words _M_local_word[_S_local_word_size]; 588 589 // Allocated storage. 590 int _M_word_size; 591 _Words* _M_word; 592 593 _Words& 594 _M_grow_words(int __index, bool __iword); 595 596 // Members for locale and locale caching. 597 locale _M_ios_locale; 598 599 void 600 _M_init() throw(); 601 602 public: 603 604 // 27.4.2.1.6 Class ios_base::Init 605 // Used to initialize standard streams. In theory, g++ could use 606 // -finit-priority to order this stuff correctly without going 607 // through these machinations. 608 class Init 609 { 610 friend class ios_base; 611 public: 612 Init(); 613 ~Init(); 614 615 #if __cplusplus >= 201103L 616 Init(const Init&) = default; 617 Init& operator=(const Init&) = default; 618 #endif 619 620 private: 621 static _Atomic_word _S_refcount; 622 static bool _S_synced_with_stdio; 623 }; 624 625 // [27.4.2.2] fmtflags state functions 626 /** 627 * @brief Access to format flags. 628 * @return The format control flags for both input and output. 629 */ 630 fmtflags 631 flags() const 632 { return _M_flags; } 633 634 /** 635 * @brief Setting new format flags all at once. 636 * @param __fmtfl The new flags to set. 637 * @return The previous format control flags. 638 * 639 * This function overwrites all the format flags with @a __fmtfl. 640 */ 641 fmtflags 642 flags(fmtflags __fmtfl) 643 { 644 fmtflags __old = _M_flags; 645 _M_flags = __fmtfl; 646 return __old; 647 } 648 649 /** 650 * @brief Setting new format flags. 651 * @param __fmtfl Additional flags to set. 652 * @return The previous format control flags. 653 * 654 * This function sets additional flags in format control. Flags that 655 * were previously set remain set. 656 */ 657 fmtflags 658 setf(fmtflags __fmtfl) 659 { 660 fmtflags __old = _M_flags; 661 _M_flags |= __fmtfl; 662 return __old; 663 } 664 665 /** 666 * @brief Setting new format flags. 667 * @param __fmtfl Additional flags to set. 668 * @param __mask The flags mask for @a fmtfl. 669 * @return The previous format control flags. 670 * 671 * This function clears @a mask in the format flags, then sets 672 * @a fmtfl @c & @a mask. An example mask is @c ios_base::adjustfield. 673 */ 674 fmtflags 675 setf(fmtflags __fmtfl, fmtflags __mask) 676 { 677 fmtflags __old = _M_flags; 678 _M_flags &= ~__mask; 679 _M_flags |= (__fmtfl & __mask); 680 return __old; 681 } 682 683 /** 684 * @brief Clearing format flags. 685 * @param __mask The flags to unset. 686 * 687 * This function clears @a __mask in the format flags. 688 */ 689 void 690 unsetf(fmtflags __mask) 691 { _M_flags &= ~__mask; } 692 693 /** 694 * @brief Flags access. 695 * @return The precision to generate on certain output operations. 696 * 697 * Be careful if you try to give a definition of @a precision here; see 698 * DR 189. 699 */ 700 streamsize 701 precision() const 702 { return _M_precision; } 703 704 /** 705 * @brief Changing flags. 706 * @param __prec The new precision value. 707 * @return The previous value of precision(). 708 */ 709 streamsize 710 precision(streamsize __prec) 711 { 712 streamsize __old = _M_precision; 713 _M_precision = __prec; 714 return __old; 715 } 716 717 /** 718 * @brief Flags access. 719 * @return The minimum field width to generate on output operations. 720 * 721 * <em>Minimum field width</em> refers to the number of characters. 722 */ 723 streamsize 724 width() const 725 { return _M_width; } 726 727 /** 728 * @brief Changing flags. 729 * @param __wide The new width value. 730 * @return The previous value of width(). 731 */ 732 streamsize 733 width(streamsize __wide) 734 { 735 streamsize __old = _M_width; 736 _M_width = __wide; 737 return __old; 738 } 739 740 // [27.4.2.4] ios_base static members 741 /** 742 * @brief Interaction with the standard C I/O objects. 743 * @param __sync Whether to synchronize or not. 744 * @return True if the standard streams were previously synchronized. 745 * 746 * The synchronization referred to is @e only that between the standard 747 * C facilities (e.g., stdout) and the standard C++ objects (e.g., 748 * cout). User-declared streams are unaffected. See 749 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 750 */ 751 static bool 752 sync_with_stdio(bool __sync = true); 753 754 // [27.4.2.3] ios_base locale functions 755 /** 756 * @brief Setting a new locale. 757 * @param __loc The new locale. 758 * @return The previous locale. 759 * 760 * Sets the new locale for this stream, and then invokes each callback 761 * with imbue_event. 762 */ 763 locale 764 imbue(const locale& __loc) throw(); 765 766 /** 767 * @brief Locale access 768 * @return A copy of the current locale. 769 * 770 * If @c imbue(loc) has previously been called, then this function 771 * returns @c loc. Otherwise, it returns a copy of @c std::locale(), 772 * the global C++ locale. 773 */ 774 locale 775 getloc() const 776 { return _M_ios_locale; } 777 778 /** 779 * @brief Locale access 780 * @return A reference to the current locale. 781 * 782 * Like getloc above, but returns a reference instead of 783 * generating a copy. 784 */ 785 const locale& 786 _M_getloc() const 787 { return _M_ios_locale; } 788 789 // [27.4.2.5] ios_base storage functions 790 /** 791 * @brief Access to unique indices. 792 * @return An integer different from all previous calls. 793 * 794 * This function returns a unique integer every time it is called. It 795 * can be used for any purpose, but is primarily intended to be a unique 796 * index for the iword and pword functions. The expectation is that an 797 * application calls xalloc in order to obtain an index in the iword and 798 * pword arrays that can be used without fear of conflict. 799 * 800 * The implementation maintains a static variable that is incremented and 801 * returned on each invocation. xalloc is guaranteed to return an index 802 * that is safe to use in the iword and pword arrays. 803 */ 804 static int 805 xalloc() throw(); 806 807 /** 808 * @brief Access to integer array. 809 * @param __ix Index into the array. 810 * @return A reference to an integer associated with the index. 811 * 812 * The iword function provides access to an array of integers that can be 813 * used for any purpose. The array grows as required to hold the 814 * supplied index. All integers in the array are initialized to 0. 815 * 816 * The implementation reserves several indices. You should use xalloc to 817 * obtain an index that is safe to use. Also note that since the array 818 * can grow dynamically, it is not safe to hold onto the reference. 819 */ 820 long& 821 iword(int __ix) 822 { 823 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 824 ? _M_word[__ix] : _M_grow_words(__ix, true); 825 return __word._M_iword; 826 } 827 828 /** 829 * @brief Access to void pointer array. 830 * @param __ix Index into the array. 831 * @return A reference to a void* associated with the index. 832 * 833 * The pword function provides access to an array of pointers that can be 834 * used for any purpose. The array grows as required to hold the 835 * supplied index. All pointers in the array are initialized to 0. 836 * 837 * The implementation reserves several indices. You should use xalloc to 838 * obtain an index that is safe to use. Also note that since the array 839 * can grow dynamically, it is not safe to hold onto the reference. 840 */ 841 void*& 842 pword(int __ix) 843 { 844 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 845 ? _M_word[__ix] : _M_grow_words(__ix, false); 846 return __word._M_pword; 847 } 848 849 // Destructor 850 /** 851 * Invokes each callback with erase_event. Destroys local storage. 852 * 853 * Note that the ios_base object for the standard streams never gets 854 * destroyed. As a result, any callbacks registered with the standard 855 * streams will not get invoked with erase_event (unless copyfmt is 856 * used). 857 */ 858 virtual ~ios_base(); 859 860 protected: 861 ios_base() throw (); 862 863 #if __cplusplus < 201103L 864 // _GLIBCXX_RESOLVE_LIB_DEFECTS 865 // 50. Copy constructor and assignment operator of ios_base 866 private: 867 ios_base(const ios_base&); 868 869 ios_base& 870 operator=(const ios_base&); 871 #else 872 public: 873 ios_base(const ios_base&) = delete; 874 875 ios_base& 876 operator=(const ios_base&) = delete; 877 878 protected: 879 void 880 _M_move(ios_base&) noexcept; 881 882 void 883 _M_swap(ios_base& __rhs) noexcept; 884 #endif 885 }; 886 887 // [27.4.5.1] fmtflags manipulators 888 /// Calls base.setf(ios_base::boolalpha). 889 inline ios_base& 890 boolalpha(ios_base& __base) 891 { 892 __base.setf(ios_base::boolalpha); 893 return __base; 894 } 895 896 /// Calls base.unsetf(ios_base::boolalpha). 897 inline ios_base& 898 noboolalpha(ios_base& __base) 899 { 900 __base.unsetf(ios_base::boolalpha); 901 return __base; 902 } 903 904 /// Calls base.setf(ios_base::showbase). 905 inline ios_base& 906 showbase(ios_base& __base) 907 { 908 __base.setf(ios_base::showbase); 909 return __base; 910 } 911 912 /// Calls base.unsetf(ios_base::showbase). 913 inline ios_base& 914 noshowbase(ios_base& __base) 915 { 916 __base.unsetf(ios_base::showbase); 917 return __base; 918 } 919 920 /// Calls base.setf(ios_base::showpoint). 921 inline ios_base& 922 showpoint(ios_base& __base) 923 { 924 __base.setf(ios_base::showpoint); 925 return __base; 926 } 927 928 /// Calls base.unsetf(ios_base::showpoint). 929 inline ios_base& 930 noshowpoint(ios_base& __base) 931 { 932 __base.unsetf(ios_base::showpoint); 933 return __base; 934 } 935 936 /// Calls base.setf(ios_base::showpos). 937 inline ios_base& 938 showpos(ios_base& __base) 939 { 940 __base.setf(ios_base::showpos); 941 return __base; 942 } 943 944 /// Calls base.unsetf(ios_base::showpos). 945 inline ios_base& 946 noshowpos(ios_base& __base) 947 { 948 __base.unsetf(ios_base::showpos); 949 return __base; 950 } 951 952 /// Calls base.setf(ios_base::skipws). 953 inline ios_base& 954 skipws(ios_base& __base) 955 { 956 __base.setf(ios_base::skipws); 957 return __base; 958 } 959 960 /// Calls base.unsetf(ios_base::skipws). 961 inline ios_base& 962 noskipws(ios_base& __base) 963 { 964 __base.unsetf(ios_base::skipws); 965 return __base; 966 } 967 968 /// Calls base.setf(ios_base::uppercase). 969 inline ios_base& 970 uppercase(ios_base& __base) 971 { 972 __base.setf(ios_base::uppercase); 973 return __base; 974 } 975 976 /// Calls base.unsetf(ios_base::uppercase). 977 inline ios_base& 978 nouppercase(ios_base& __base) 979 { 980 __base.unsetf(ios_base::uppercase); 981 return __base; 982 } 983 984 /// Calls base.setf(ios_base::unitbuf). 985 inline ios_base& 986 unitbuf(ios_base& __base) 987 { 988 __base.setf(ios_base::unitbuf); 989 return __base; 990 } 991 992 /// Calls base.unsetf(ios_base::unitbuf). 993 inline ios_base& 994 nounitbuf(ios_base& __base) 995 { 996 __base.unsetf(ios_base::unitbuf); 997 return __base; 998 } 999 1000 // [27.4.5.2] adjustfield manipulators 1001 /// Calls base.setf(ios_base::internal, ios_base::adjustfield). 1002 inline ios_base& 1003 internal(ios_base& __base) 1004 { 1005 __base.setf(ios_base::internal, ios_base::adjustfield); 1006 return __base; 1007 } 1008 1009 /// Calls base.setf(ios_base::left, ios_base::adjustfield). 1010 inline ios_base& 1011 left(ios_base& __base) 1012 { 1013 __base.setf(ios_base::left, ios_base::adjustfield); 1014 return __base; 1015 } 1016 1017 /// Calls base.setf(ios_base::right, ios_base::adjustfield). 1018 inline ios_base& 1019 right(ios_base& __base) 1020 { 1021 __base.setf(ios_base::right, ios_base::adjustfield); 1022 return __base; 1023 } 1024 1025 // [27.4.5.3] basefield manipulators 1026 /// Calls base.setf(ios_base::dec, ios_base::basefield). 1027 inline ios_base& 1028 dec(ios_base& __base) 1029 { 1030 __base.setf(ios_base::dec, ios_base::basefield); 1031 return __base; 1032 } 1033 1034 /// Calls base.setf(ios_base::hex, ios_base::basefield). 1035 inline ios_base& 1036 hex(ios_base& __base) 1037 { 1038 __base.setf(ios_base::hex, ios_base::basefield); 1039 return __base; 1040 } 1041 1042 /// Calls base.setf(ios_base::oct, ios_base::basefield). 1043 inline ios_base& 1044 oct(ios_base& __base) 1045 { 1046 __base.setf(ios_base::oct, ios_base::basefield); 1047 return __base; 1048 } 1049 1050 // [27.4.5.4] floatfield manipulators 1051 /// Calls base.setf(ios_base::fixed, ios_base::floatfield). 1052 inline ios_base& 1053 fixed(ios_base& __base) 1054 { 1055 __base.setf(ios_base::fixed, ios_base::floatfield); 1056 return __base; 1057 } 1058 1059 /// Calls base.setf(ios_base::scientific, ios_base::floatfield). 1060 inline ios_base& 1061 scientific(ios_base& __base) 1062 { 1063 __base.setf(ios_base::scientific, ios_base::floatfield); 1064 return __base; 1065 } 1066 1067 #if __cplusplus >= 201103L 1068 // New C++11 floatfield manipulators 1069 1070 /// Calls 1071 /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield) 1072 inline ios_base& 1073 hexfloat(ios_base& __base) 1074 { 1075 __base.setf(ios_base::fixed | ios_base::scientific, ios_base::floatfield); 1076 return __base; 1077 } 1078 1079 /// Calls @c base.unsetf(ios_base::floatfield) 1080 inline ios_base& 1081 defaultfloat(ios_base& __base) 1082 { 1083 __base.unsetf(ios_base::floatfield); 1084 return __base; 1085 } 1086 #endif 1087 1088 _GLIBCXX_END_NAMESPACE_VERSION 1089 } // namespace 1090 1091 #endif /* _IOS_BASE_H */ 1092