1// Iostreams base classes -*- C++ -*- 2 3// Copyright (C) 1997-2022 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_noreplace = 1L << 6, 120 _S_ios_openmode_end = 1L << 16, 121 _S_ios_openmode_max = __INT_MAX__, 122 _S_ios_openmode_min = ~__INT_MAX__ 123 }; 124 125 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 126 operator&(_Ios_Openmode __a, _Ios_Openmode __b) 127 { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); } 128 129 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 130 operator|(_Ios_Openmode __a, _Ios_Openmode __b) 131 { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); } 132 133 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 134 operator^(_Ios_Openmode __a, _Ios_Openmode __b) 135 { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); } 136 137 inline _GLIBCXX_CONSTEXPR _Ios_Openmode 138 operator~(_Ios_Openmode __a) 139 { return _Ios_Openmode(~static_cast<int>(__a)); } 140 141 inline const _Ios_Openmode& 142 operator|=(_Ios_Openmode& __a, _Ios_Openmode __b) 143 { return __a = __a | __b; } 144 145 inline const _Ios_Openmode& 146 operator&=(_Ios_Openmode& __a, _Ios_Openmode __b) 147 { return __a = __a & __b; } 148 149 inline const _Ios_Openmode& 150 operator^=(_Ios_Openmode& __a, _Ios_Openmode __b) 151 { return __a = __a ^ __b; } 152 153 154 enum _Ios_Iostate 155 { 156 _S_goodbit = 0, 157 _S_badbit = 1L << 0, 158 _S_eofbit = 1L << 1, 159 _S_failbit = 1L << 2, 160 _S_ios_iostate_end = 1L << 16, 161 _S_ios_iostate_max = __INT_MAX__, 162 _S_ios_iostate_min = ~__INT_MAX__ 163 }; 164 165 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 166 operator&(_Ios_Iostate __a, _Ios_Iostate __b) 167 { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); } 168 169 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 170 operator|(_Ios_Iostate __a, _Ios_Iostate __b) 171 { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); } 172 173 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 174 operator^(_Ios_Iostate __a, _Ios_Iostate __b) 175 { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); } 176 177 inline _GLIBCXX_CONSTEXPR _Ios_Iostate 178 operator~(_Ios_Iostate __a) 179 { return _Ios_Iostate(~static_cast<int>(__a)); } 180 181 inline const _Ios_Iostate& 182 operator|=(_Ios_Iostate& __a, _Ios_Iostate __b) 183 { return __a = __a | __b; } 184 185 inline const _Ios_Iostate& 186 operator&=(_Ios_Iostate& __a, _Ios_Iostate __b) 187 { return __a = __a & __b; } 188 189 inline const _Ios_Iostate& 190 operator^=(_Ios_Iostate& __a, _Ios_Iostate __b) 191 { return __a = __a ^ __b; } 192 193 194 enum _Ios_Seekdir 195 { 196 _S_beg = 0, 197 _S_cur = _GLIBCXX_STDIO_SEEK_CUR, 198 _S_end = _GLIBCXX_STDIO_SEEK_END, 199 _S_ios_seekdir_end = 1L << 16 200 }; 201 202#if __cplusplus >= 201103L 203 /// I/O error code 204 enum class io_errc { stream = 1 }; 205 206 template <> struct is_error_code_enum<io_errc> : public true_type { }; 207 208 [[__nodiscard__, __gnu__::__const__]] 209 const error_category& 210 iostream_category() noexcept; 211 212 [[__nodiscard__]] 213 inline error_code 214 make_error_code(io_errc __e) noexcept 215 { return error_code(static_cast<int>(__e), iostream_category()); } 216 217 [[__nodiscard__]] 218 inline error_condition 219 make_error_condition(io_errc __e) noexcept 220 { return error_condition(static_cast<int>(__e), iostream_category()); } 221#endif 222 223 // 27.4.2 Class ios_base 224 /** 225 * @brief The base of the I/O class hierarchy. 226 * @ingroup io 227 * 228 * This class defines everything that can be defined about I/O that does 229 * not depend on the type of characters being input or output. Most 230 * people will only see @c ios_base when they need to specify the full 231 * name of the various I/O flags (e.g., the openmodes). 232 */ 233 class ios_base 234 { 235#if _GLIBCXX_USE_CXX11_ABI 236#if __cplusplus < 201103L 237 // Type that is layout-compatible with std::system_error 238 struct system_error : std::runtime_error 239 { 240 // Type that is layout-compatible with std::error_code 241 struct error_code 242 { 243 error_code() { } 244 private: 245 int _M_value; 246 const void* _M_cat; 247 } _M_code; 248 }; 249#endif 250#endif 251 public: 252 253 /** 254 * @brief These are thrown to indicate problems with io. 255 * @ingroup exceptions 256 * 257 * 27.4.2.1.1 Class ios_base::failure 258 */ 259#if _GLIBCXX_USE_CXX11_ABI 260 class _GLIBCXX_ABI_TAG_CXX11 failure : public system_error 261 { 262 public: 263 explicit 264 failure(const string& __str); 265 266#if __cplusplus >= 201103L 267 explicit 268 failure(const string&, const error_code&); 269 270 explicit 271 failure(const char*, const error_code& = io_errc::stream); 272#endif 273 274 virtual 275 ~failure() throw(); 276 277 virtual const char* 278 what() const throw(); 279 }; 280#else 281 class failure : public exception 282 { 283 public: 284 // _GLIBCXX_RESOLVE_LIB_DEFECTS 285 // 48. Use of non-existent exception constructor 286 explicit 287 failure(const string& __str) throw(); 288 289 // This declaration is not useless: 290 // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html 291 virtual 292 ~failure() throw(); 293 294 virtual const char* 295 what() const throw(); 296 297#if __cplusplus >= 201103L 298 // Define the new members required by C++11, 299 // even though the error_code cannot be stored. 300 301 explicit 302 failure(const string& __s, const error_code&) noexcept 303 : failure(__s) 304 { } 305 306 explicit 307 failure(const char* __s, const error_code& = error_code{}) 308 : failure(string(__s)) 309 { } 310 311 // Stand-in for system_error::code() but returning by value. 312 error_code code() const noexcept { return error_code{}; } 313#endif 314 315 private: 316 string _M_msg; 317 }; 318#endif 319 320 // 27.4.2.1.2 Type ios_base::fmtflags 321 /** 322 * @brief This is a bitmask type. 323 * 324 * @c @a _Ios_Fmtflags is implementation-defined, but it is valid to 325 * perform bitwise operations on these values and expect the Right 326 * Thing to happen. Defined objects of type fmtflags are: 327 * - boolalpha 328 * - dec 329 * - fixed 330 * - hex 331 * - internal 332 * - left 333 * - oct 334 * - right 335 * - scientific 336 * - showbase 337 * - showpoint 338 * - showpos 339 * - skipws 340 * - unitbuf 341 * - uppercase 342 * - adjustfield 343 * - basefield 344 * - floatfield 345 */ 346 typedef _Ios_Fmtflags fmtflags; 347 348 /// Insert/extract @c bool in alphabetic rather than numeric format. 349 static const fmtflags boolalpha = _S_boolalpha; 350 351 /// Converts integer input or generates integer output in decimal base. 352 static const fmtflags dec = _S_dec; 353 354 /// Generate floating-point output in fixed-point notation. 355 static const fmtflags fixed = _S_fixed; 356 357 /// Converts integer input or generates integer output in hexadecimal base. 358 static const fmtflags hex = _S_hex; 359 360 /// Adds fill characters at a designated internal point in certain 361 /// generated output, or identical to @c right if no such point is 362 /// designated. 363 static const fmtflags internal = _S_internal; 364 365 /// Adds fill characters on the right (final positions) of certain 366 /// generated output. (I.e., the thing you print is flush left.) 367 static const fmtflags left = _S_left; 368 369 /// Converts integer input or generates integer output in octal base. 370 static const fmtflags oct = _S_oct; 371 372 /// Adds fill characters on the left (initial positions) of certain 373 /// generated output. (I.e., the thing you print is flush right.) 374 static const fmtflags right = _S_right; 375 376 /// Generates floating-point output in scientific notation. 377 static const fmtflags scientific = _S_scientific; 378 379 /// Generates a prefix indicating the numeric base of generated integer 380 /// output. 381 static const fmtflags showbase = _S_showbase; 382 383 /// Generates a decimal-point character unconditionally in generated 384 /// floating-point output. 385 static const fmtflags showpoint = _S_showpoint; 386 387 /// Generates a + sign in non-negative generated numeric output. 388 static const fmtflags showpos = _S_showpos; 389 390 /// Skips leading white space before certain input operations. 391 static const fmtflags skipws = _S_skipws; 392 393 /// Flushes output after each output operation. 394 static const fmtflags unitbuf = _S_unitbuf; 395 396 /// Replaces certain lowercase letters with their uppercase equivalents 397 /// in generated output. 398 static const fmtflags uppercase = _S_uppercase; 399 400 /// A mask of left|right|internal. Useful for the 2-arg form of @c setf. 401 static const fmtflags adjustfield = _S_adjustfield; 402 403 /// A mask of dec|oct|hex. Useful for the 2-arg form of @c setf. 404 static const fmtflags basefield = _S_basefield; 405 406 /// A mask of scientific|fixed. Useful for the 2-arg form of @c setf. 407 static const fmtflags floatfield = _S_floatfield; 408 409 // 27.4.2.1.3 Type ios_base::iostate 410 /** 411 * @brief This is a bitmask type. 412 * 413 * @c @a _Ios_Iostate is implementation-defined, but it is valid to 414 * perform bitwise operations on these values and expect the Right 415 * Thing to happen. Defined objects of type iostate are: 416 * - badbit 417 * - eofbit 418 * - failbit 419 * - goodbit 420 */ 421 typedef _Ios_Iostate iostate; 422 423 /// Indicates a loss of integrity in an input or output sequence (such 424 /// as an irrecoverable read error from a file). 425 static const iostate badbit = _S_badbit; 426 427 /// Indicates that an input operation reached the end of an input sequence. 428 static const iostate eofbit = _S_eofbit; 429 430 /// Indicates that an input operation failed to read the expected 431 /// characters, or that an output operation failed to generate the 432 /// desired characters. 433 static const iostate failbit = _S_failbit; 434 435 /// Indicates all is well. 436 static const iostate goodbit = _S_goodbit; 437 438 // 27.4.2.1.4 Type ios_base::openmode 439 /** 440 * @brief This is a bitmask type. 441 * 442 * @c @a _Ios_Openmode is implementation-defined, but it is valid to 443 * perform bitwise operations on these values and expect the Right 444 * Thing to happen. Defined objects of type openmode are: 445 * - app 446 * - ate 447 * - binary 448 * - in 449 * - out 450 * - trunc 451 */ 452 typedef _Ios_Openmode openmode; 453 454 /// Seek to end before each write. 455 static const openmode app = _S_app; 456 457 /// Open and seek to end immediately after opening. 458 static const openmode ate = _S_ate; 459 460 /// Perform input and output in binary mode (as opposed to text mode). 461 /// This is probably not what you think it is; see 462 /// https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 463 static const openmode binary = _S_bin; 464 465 /// Open for input. Default for @c ifstream and fstream. 466 static const openmode in = _S_in; 467 468 /// Open for output. Default for @c ofstream and fstream. 469 static const openmode out = _S_out; 470 471 /// Truncate an existing stream when opening. Default for @c ofstream. 472 static const openmode trunc = _S_trunc; 473 474 static const openmode __noreplace = _S_noreplace; 475 476#if __cplusplus >= 202100L 477#define __cpp_lib_ios_noreplace 202207L 478 /// Open a file in exclusive mode. 479 static const openmode noreplace = _S_noreplace; 480#endif 481 482 // 27.4.2.1.5 Type ios_base::seekdir 483 /** 484 * @brief This is an enumerated type. 485 * 486 * @c @a _Ios_Seekdir is implementation-defined. Defined values 487 * of type seekdir are: 488 * - beg 489 * - cur, equivalent to @c SEEK_CUR in the C standard library. 490 * - end, equivalent to @c SEEK_END in the C standard library. 491 */ 492 typedef _Ios_Seekdir seekdir; 493 494 /// Request a seek relative to the beginning of the stream. 495 static const seekdir beg = _S_beg; 496 497 /// Request a seek relative to the current position within the sequence. 498 static const seekdir cur = _S_cur; 499 500 /// Request a seek relative to the current end of the sequence. 501 static const seekdir end = _S_end; 502 503#if __cplusplus <= 201402L 504 // Annex D.6 (removed in C++17) 505 typedef int io_state 506 _GLIBCXX_DEPRECATED_SUGGEST("std::iostate"); 507 typedef int open_mode 508 _GLIBCXX_DEPRECATED_SUGGEST("std::openmode"); 509 typedef int seek_dir 510 _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir"); 511 512 typedef std::streampos streampos 513 _GLIBCXX_DEPRECATED_SUGGEST("std::streampos"); 514 typedef std::streamoff streamoff 515 _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff"); 516#endif 517 518 // Callbacks; 519 /** 520 * @brief The set of events that may be passed to an event callback. 521 * 522 * erase_event is used during ~ios() and copyfmt(). imbue_event is used 523 * during imbue(). copyfmt_event is used during copyfmt(). 524 */ 525 enum event 526 { 527 erase_event, 528 imbue_event, 529 copyfmt_event 530 }; 531 532 /** 533 * @brief The type of an event callback function. 534 * @param __e One of the members of the event enum. 535 * @param __b Reference to the ios_base object. 536 * @param __i The integer provided when the callback was registered. 537 * 538 * Event callbacks are user defined functions that get called during 539 * several ios_base and basic_ios functions, specifically imbue(), 540 * copyfmt(), and ~ios(). 541 */ 542 typedef void (*event_callback) (event __e, ios_base& __b, int __i); 543 544 /** 545 * @brief Add the callback __fn with parameter __index. 546 * @param __fn The function to add. 547 * @param __index The integer to pass to the function when invoked. 548 * 549 * Registers a function as an event callback with an integer parameter to 550 * be passed to the function when invoked. Multiple copies of the 551 * function are allowed. If there are multiple callbacks, they are 552 * invoked in the order they were registered. 553 */ 554 void 555 register_callback(event_callback __fn, int __index); 556 557 protected: 558 streamsize _M_precision; 559 streamsize _M_width; 560 fmtflags _M_flags; 561 iostate _M_exception; 562 iostate _M_streambuf_state; 563 564 // 27.4.2.6 Members for callbacks 565 // 27.4.2.6 ios_base callbacks 566 struct _Callback_list 567 { 568 // Data Members 569 _Callback_list* _M_next; 570 ios_base::event_callback _M_fn; 571 int _M_index; 572 _Atomic_word _M_refcount; // 0 means one reference. 573 574 _Callback_list(ios_base::event_callback __fn, int __index, 575 _Callback_list* __cb) 576 : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { } 577 578 void 579 _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); } 580 581 // 0 => OK to delete. 582 int 583 _M_remove_reference() 584 { 585 // Be race-detector-friendly. For more info see bits/c++config. 586 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount); 587 int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1); 588 if (__res == 0) 589 { 590 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount); 591 } 592 return __res; 593 } 594 }; 595 596 _Callback_list* _M_callbacks; 597 598 void 599 _M_call_callbacks(event __ev) throw(); 600 601 void 602 _M_dispose_callbacks(void) throw(); 603 604 // 27.4.2.5 Members for iword/pword storage 605 struct _Words 606 { 607 void* _M_pword; 608 long _M_iword; 609 _Words() : _M_pword(0), _M_iword(0) { } 610 }; 611 612 // Only for failed iword/pword calls. 613 _Words _M_word_zero; 614 615 // Guaranteed storage. 616 // The first 5 iword and pword slots are reserved for internal use. 617 enum { _S_local_word_size = 8 }; 618 _Words _M_local_word[_S_local_word_size]; 619 620 // Allocated storage. 621 int _M_word_size; 622 _Words* _M_word; 623 624 _Words& 625 _M_grow_words(int __index, bool __iword); 626 627 // Members for locale and locale caching. 628 locale _M_ios_locale; 629 630 void 631 _M_init() throw(); 632 633 public: 634 635 // 27.4.2.1.6 Class ios_base::Init 636 // Used to initialize standard streams. In theory, g++ could use 637 // -finit-priority to order this stuff correctly without going 638 // through these machinations. 639 class Init 640 { 641 friend class ios_base; 642 public: 643 Init(); 644 ~Init(); 645 646#if __cplusplus >= 201103L 647 Init(const Init&) = default; 648 Init& operator=(const Init&) = default; 649#endif 650 651 private: 652 static _Atomic_word _S_refcount; 653 static bool _S_synced_with_stdio; 654 }; 655 656 // [27.4.2.2] fmtflags state functions 657 /** 658 * @brief Access to format flags. 659 * @return The format control flags for both input and output. 660 */ 661 fmtflags 662 flags() const 663 { return _M_flags; } 664 665 /** 666 * @brief Setting new format flags all at once. 667 * @param __fmtfl The new flags to set. 668 * @return The previous format control flags. 669 * 670 * This function overwrites all the format flags with @a __fmtfl. 671 */ 672 fmtflags 673 flags(fmtflags __fmtfl) 674 { 675 fmtflags __old = _M_flags; 676 _M_flags = __fmtfl; 677 return __old; 678 } 679 680 /** 681 * @brief Setting new format flags. 682 * @param __fmtfl Additional flags to set. 683 * @return The previous format control flags. 684 * 685 * This function sets additional flags in format control. Flags that 686 * were previously set remain set. 687 */ 688 fmtflags 689 setf(fmtflags __fmtfl) 690 { 691 fmtflags __old = _M_flags; 692 _M_flags |= __fmtfl; 693 return __old; 694 } 695 696 /** 697 * @brief Setting new format flags. 698 * @param __fmtfl Additional flags to set. 699 * @param __mask The flags mask for @a fmtfl. 700 * @return The previous format control flags. 701 * 702 * This function clears @a mask in the format flags, then sets 703 * @a fmtfl @c & @a mask. An example mask is @c ios_base::adjustfield. 704 */ 705 fmtflags 706 setf(fmtflags __fmtfl, fmtflags __mask) 707 { 708 fmtflags __old = _M_flags; 709 _M_flags &= ~__mask; 710 _M_flags |= (__fmtfl & __mask); 711 return __old; 712 } 713 714 /** 715 * @brief Clearing format flags. 716 * @param __mask The flags to unset. 717 * 718 * This function clears @a __mask in the format flags. 719 */ 720 void 721 unsetf(fmtflags __mask) 722 { _M_flags &= ~__mask; } 723 724 /** 725 * @brief Flags access. 726 * @return The precision to generate on certain output operations. 727 * 728 * Be careful if you try to give a definition of @a precision here; see 729 * DR 189. 730 */ 731 streamsize 732 precision() const 733 { return _M_precision; } 734 735 /** 736 * @brief Changing flags. 737 * @param __prec The new precision value. 738 * @return The previous value of precision(). 739 */ 740 streamsize 741 precision(streamsize __prec) 742 { 743 streamsize __old = _M_precision; 744 _M_precision = __prec; 745 return __old; 746 } 747 748 /** 749 * @brief Flags access. 750 * @return The minimum field width to generate on output operations. 751 * 752 * <em>Minimum field width</em> refers to the number of characters. 753 */ 754 streamsize 755 width() const 756 { return _M_width; } 757 758 /** 759 * @brief Changing flags. 760 * @param __wide The new width value. 761 * @return The previous value of width(). 762 */ 763 streamsize 764 width(streamsize __wide) 765 { 766 streamsize __old = _M_width; 767 _M_width = __wide; 768 return __old; 769 } 770 771 // [27.4.2.4] ios_base static members 772 /** 773 * @brief Interaction with the standard C I/O objects. 774 * @param __sync Whether to synchronize or not. 775 * @return True if the standard streams were previously synchronized. 776 * 777 * The synchronization referred to is @e only that between the standard 778 * C facilities (e.g., stdout) and the standard C++ objects (e.g., 779 * cout). User-declared streams are unaffected. See 780 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 781 */ 782 static bool 783 sync_with_stdio(bool __sync = true); 784 785 // [27.4.2.3] ios_base locale functions 786 /** 787 * @brief Setting a new locale. 788 * @param __loc The new locale. 789 * @return The previous locale. 790 * 791 * Sets the new locale for this stream, and then invokes each callback 792 * with imbue_event. 793 */ 794 locale 795 imbue(const locale& __loc) throw(); 796 797 /** 798 * @brief Locale access 799 * @return A copy of the current locale. 800 * 801 * If @c imbue(loc) has previously been called, then this function 802 * returns @c loc. Otherwise, it returns a copy of @c std::locale(), 803 * the global C++ locale. 804 */ 805 locale 806 getloc() const 807 { return _M_ios_locale; } 808 809 /** 810 * @brief Locale access 811 * @return A reference to the current locale. 812 * 813 * Like getloc above, but returns a reference instead of 814 * generating a copy. 815 */ 816 const locale& 817 _M_getloc() const 818 { return _M_ios_locale; } 819 820 // [27.4.2.5] ios_base storage functions 821 /** 822 * @brief Access to unique indices. 823 * @return An integer different from all previous calls. 824 * 825 * This function returns a unique integer every time it is called. It 826 * can be used for any purpose, but is primarily intended to be a unique 827 * index for the iword and pword functions. The expectation is that an 828 * application calls xalloc in order to obtain an index in the iword and 829 * pword arrays that can be used without fear of conflict. 830 * 831 * The implementation maintains a static variable that is incremented and 832 * returned on each invocation. xalloc is guaranteed to return an index 833 * that is safe to use in the iword and pword arrays. 834 */ 835 static int 836 xalloc() throw(); 837 838 /** 839 * @brief Access to integer array. 840 * @param __ix Index into the array. 841 * @return A reference to an integer associated with the index. 842 * 843 * The iword function provides access to an array of integers that can be 844 * used for any purpose. The array grows as required to hold the 845 * supplied index. All integers in the array are initialized to 0. 846 * 847 * The implementation reserves several indices. You should use xalloc to 848 * obtain an index that is safe to use. Also note that since the array 849 * can grow dynamically, it is not safe to hold onto the reference. 850 */ 851 long& 852 iword(int __ix) 853 { 854 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 855 ? _M_word[__ix] : _M_grow_words(__ix, true); 856 return __word._M_iword; 857 } 858 859 /** 860 * @brief Access to void pointer array. 861 * @param __ix Index into the array. 862 * @return A reference to a void* associated with the index. 863 * 864 * The pword function provides access to an array of pointers that can be 865 * used for any purpose. The array grows as required to hold the 866 * supplied index. All pointers in the array are initialized to 0. 867 * 868 * The implementation reserves several indices. You should use xalloc to 869 * obtain an index that is safe to use. Also note that since the array 870 * can grow dynamically, it is not safe to hold onto the reference. 871 */ 872 void*& 873 pword(int __ix) 874 { 875 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 876 ? _M_word[__ix] : _M_grow_words(__ix, false); 877 return __word._M_pword; 878 } 879 880 // Destructor 881 /** 882 * Invokes each callback with erase_event. Destroys local storage. 883 * 884 * Note that the ios_base object for the standard streams never gets 885 * destroyed. As a result, any callbacks registered with the standard 886 * streams will not get invoked with erase_event (unless copyfmt is 887 * used). 888 */ 889 virtual ~ios_base(); 890 891 protected: 892 ios_base() throw (); 893 894#if __cplusplus < 201103L 895 // _GLIBCXX_RESOLVE_LIB_DEFECTS 896 // 50. Copy constructor and assignment operator of ios_base 897 private: 898 ios_base(const ios_base&); 899 900 ios_base& 901 operator=(const ios_base&); 902#else 903 public: 904 ios_base(const ios_base&) = delete; 905 906 ios_base& 907 operator=(const ios_base&) = delete; 908 909 protected: 910 void 911 _M_move(ios_base&) noexcept; 912 913 void 914 _M_swap(ios_base& __rhs) noexcept; 915#endif 916 }; 917 918 // [27.4.5.1] fmtflags manipulators 919 /// Calls base.setf(ios_base::boolalpha). 920 inline ios_base& 921 boolalpha(ios_base& __base) 922 { 923 __base.setf(ios_base::boolalpha); 924 return __base; 925 } 926 927 /// Calls base.unsetf(ios_base::boolalpha). 928 inline ios_base& 929 noboolalpha(ios_base& __base) 930 { 931 __base.unsetf(ios_base::boolalpha); 932 return __base; 933 } 934 935 /// Calls base.setf(ios_base::showbase). 936 inline ios_base& 937 showbase(ios_base& __base) 938 { 939 __base.setf(ios_base::showbase); 940 return __base; 941 } 942 943 /// Calls base.unsetf(ios_base::showbase). 944 inline ios_base& 945 noshowbase(ios_base& __base) 946 { 947 __base.unsetf(ios_base::showbase); 948 return __base; 949 } 950 951 /// Calls base.setf(ios_base::showpoint). 952 inline ios_base& 953 showpoint(ios_base& __base) 954 { 955 __base.setf(ios_base::showpoint); 956 return __base; 957 } 958 959 /// Calls base.unsetf(ios_base::showpoint). 960 inline ios_base& 961 noshowpoint(ios_base& __base) 962 { 963 __base.unsetf(ios_base::showpoint); 964 return __base; 965 } 966 967 /// Calls base.setf(ios_base::showpos). 968 inline ios_base& 969 showpos(ios_base& __base) 970 { 971 __base.setf(ios_base::showpos); 972 return __base; 973 } 974 975 /// Calls base.unsetf(ios_base::showpos). 976 inline ios_base& 977 noshowpos(ios_base& __base) 978 { 979 __base.unsetf(ios_base::showpos); 980 return __base; 981 } 982 983 /// Calls base.setf(ios_base::skipws). 984 inline ios_base& 985 skipws(ios_base& __base) 986 { 987 __base.setf(ios_base::skipws); 988 return __base; 989 } 990 991 /// Calls base.unsetf(ios_base::skipws). 992 inline ios_base& 993 noskipws(ios_base& __base) 994 { 995 __base.unsetf(ios_base::skipws); 996 return __base; 997 } 998 999 /// Calls base.setf(ios_base::uppercase). 1000 inline ios_base& 1001 uppercase(ios_base& __base) 1002 { 1003 __base.setf(ios_base::uppercase); 1004 return __base; 1005 } 1006 1007 /// Calls base.unsetf(ios_base::uppercase). 1008 inline ios_base& 1009 nouppercase(ios_base& __base) 1010 { 1011 __base.unsetf(ios_base::uppercase); 1012 return __base; 1013 } 1014 1015 /// Calls base.setf(ios_base::unitbuf). 1016 inline ios_base& 1017 unitbuf(ios_base& __base) 1018 { 1019 __base.setf(ios_base::unitbuf); 1020 return __base; 1021 } 1022 1023 /// Calls base.unsetf(ios_base::unitbuf). 1024 inline ios_base& 1025 nounitbuf(ios_base& __base) 1026 { 1027 __base.unsetf(ios_base::unitbuf); 1028 return __base; 1029 } 1030 1031 // [27.4.5.2] adjustfield manipulators 1032 /// Calls base.setf(ios_base::internal, ios_base::adjustfield). 1033 inline ios_base& 1034 internal(ios_base& __base) 1035 { 1036 __base.setf(ios_base::internal, ios_base::adjustfield); 1037 return __base; 1038 } 1039 1040 /// Calls base.setf(ios_base::left, ios_base::adjustfield). 1041 inline ios_base& 1042 left(ios_base& __base) 1043 { 1044 __base.setf(ios_base::left, ios_base::adjustfield); 1045 return __base; 1046 } 1047 1048 /// Calls base.setf(ios_base::right, ios_base::adjustfield). 1049 inline ios_base& 1050 right(ios_base& __base) 1051 { 1052 __base.setf(ios_base::right, ios_base::adjustfield); 1053 return __base; 1054 } 1055 1056 // [27.4.5.3] basefield manipulators 1057 /// Calls base.setf(ios_base::dec, ios_base::basefield). 1058 inline ios_base& 1059 dec(ios_base& __base) 1060 { 1061 __base.setf(ios_base::dec, ios_base::basefield); 1062 return __base; 1063 } 1064 1065 /// Calls base.setf(ios_base::hex, ios_base::basefield). 1066 inline ios_base& 1067 hex(ios_base& __base) 1068 { 1069 __base.setf(ios_base::hex, ios_base::basefield); 1070 return __base; 1071 } 1072 1073 /// Calls base.setf(ios_base::oct, ios_base::basefield). 1074 inline ios_base& 1075 oct(ios_base& __base) 1076 { 1077 __base.setf(ios_base::oct, ios_base::basefield); 1078 return __base; 1079 } 1080 1081 // [27.4.5.4] floatfield manipulators 1082 /// Calls base.setf(ios_base::fixed, ios_base::floatfield). 1083 inline ios_base& 1084 fixed(ios_base& __base) 1085 { 1086 __base.setf(ios_base::fixed, ios_base::floatfield); 1087 return __base; 1088 } 1089 1090 /// Calls base.setf(ios_base::scientific, ios_base::floatfield). 1091 inline ios_base& 1092 scientific(ios_base& __base) 1093 { 1094 __base.setf(ios_base::scientific, ios_base::floatfield); 1095 return __base; 1096 } 1097 1098#if __cplusplus >= 201103L 1099 // New C++11 floatfield manipulators 1100 1101 /// Calls 1102 /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield) 1103 inline ios_base& 1104 hexfloat(ios_base& __base) 1105 { 1106 __base.setf(ios_base::fixed | ios_base::scientific, ios_base::floatfield); 1107 return __base; 1108 } 1109 1110 /// Calls @c base.unsetf(ios_base::floatfield) 1111 inline ios_base& 1112 defaultfloat(ios_base& __base) 1113 { 1114 __base.unsetf(ios_base::floatfield); 1115 return __base; 1116 } 1117#endif 1118 1119_GLIBCXX_END_NAMESPACE_VERSION 1120} // namespace 1121 1122#endif /* _IOS_BASE_H */ 1123