1// Iostreams base classes -*- C++ -*- 2 3// Copyright (C) 1997-2020 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(&_M_refcount, 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(&_M_refcount, -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(__ix, 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(__ix, 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(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(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(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(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(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(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(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(ios_base::internal, 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(ios_base::left, 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(ios_base::right, 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(ios_base::dec, 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(ios_base::hex, 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(ios_base::oct, 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(ios_base::fixed, 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(ios_base::scientific, 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(ios_base::fixed | ios_base::scientific, 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(ios_base::floatfield); 1102 return __base; 1103 } 1104#endif 1105 1106_GLIBCXX_END_NAMESPACE_VERSION 1107} // namespace 1108 1109#endif /* _IOS_BASE_H */ 1110