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 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 typedef int open_mode; 476 typedef int seek_dir; 477 478 typedef std::streampos streampos; 479 typedef std::streamoff streamoff; 480 #endif 481 482 // Callbacks; 483 /** 484 * @brief The set of events that may be passed to an event callback. 485 * 486 * erase_event is used during ~ios() and copyfmt(). imbue_event is used 487 * during imbue(). copyfmt_event is used during copyfmt(). 488 */ 489 enum event 490 { 491 erase_event, 492 imbue_event, 493 copyfmt_event 494 }; 495 496 /** 497 * @brief The type of an event callback function. 498 * @param __e One of the members of the event enum. 499 * @param __b Reference to the ios_base object. 500 * @param __i The integer provided when the callback was registered. 501 * 502 * Event callbacks are user defined functions that get called during 503 * several ios_base and basic_ios functions, specifically imbue(), 504 * copyfmt(), and ~ios(). 505 */ 506 typedef void (*event_callback) (event __e, ios_base& __b, int __i); 507 508 /** 509 * @brief Add the callback __fn with parameter __index. 510 * @param __fn The function to add. 511 * @param __index The integer to pass to the function when invoked. 512 * 513 * Registers a function as an event callback with an integer parameter to 514 * be passed to the function when invoked. Multiple copies of the 515 * function are allowed. If there are multiple callbacks, they are 516 * invoked in the order they were registered. 517 */ 518 void 519 register_callback(event_callback __fn, int __index); 520 521 protected: 522 streamsize _M_precision; 523 streamsize _M_width; 524 fmtflags _M_flags; 525 iostate _M_exception; 526 iostate _M_streambuf_state; 527 528 // 27.4.2.6 Members for callbacks 529 // 27.4.2.6 ios_base callbacks 530 struct _Callback_list 531 { 532 // Data Members 533 _Callback_list* _M_next; 534 ios_base::event_callback _M_fn; 535 int _M_index; 536 _Atomic_word _M_refcount; // 0 means one reference. 537 538 _Callback_list(ios_base::event_callback __fn, int __index, 539 _Callback_list* __cb) 540 : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { } 541 542 void 543 _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); } 544 545 // 0 => OK to delete. 546 int 547 _M_remove_reference() 548 { 549 // Be race-detector-friendly. For more info see bits/c++config. 550 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount); 551 int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1); 552 if (__res == 0) 553 { 554 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount); 555 } 556 return __res; 557 } 558 }; 559 560 _Callback_list* _M_callbacks; 561 562 void 563 _M_call_callbacks(event __ev) throw(); 564 565 void 566 _M_dispose_callbacks(void) throw(); 567 568 // 27.4.2.5 Members for iword/pword storage 569 struct _Words 570 { 571 void* _M_pword; 572 long _M_iword; 573 _Words() : _M_pword(0), _M_iword(0) { } 574 }; 575 576 // Only for failed iword/pword calls. 577 _Words _M_word_zero; 578 579 // Guaranteed storage. 580 // The first 5 iword and pword slots are reserved for internal use. 581 enum { _S_local_word_size = 8 }; 582 _Words _M_local_word[_S_local_word_size]; 583 584 // Allocated storage. 585 int _M_word_size; 586 _Words* _M_word; 587 588 _Words& 589 _M_grow_words(int __index, bool __iword); 590 591 // Members for locale and locale caching. 592 locale _M_ios_locale; 593 594 void 595 _M_init() throw(); 596 597 public: 598 599 // 27.4.2.1.6 Class ios_base::Init 600 // Used to initialize standard streams. In theory, g++ could use 601 // -finit-priority to order this stuff correctly without going 602 // through these machinations. 603 class Init 604 { 605 friend class ios_base; 606 public: 607 Init(); 608 ~Init(); 609 610 #if __cplusplus >= 201103L 611 Init(const Init&) = default; 612 Init& operator=(const Init&) = default; 613 #endif 614 615 private: 616 static _Atomic_word _S_refcount; 617 static bool _S_synced_with_stdio; 618 }; 619 620 // [27.4.2.2] fmtflags state functions 621 /** 622 * @brief Access to format flags. 623 * @return The format control flags for both input and output. 624 */ 625 fmtflags 626 flags() const 627 { return _M_flags; } 628 629 /** 630 * @brief Setting new format flags all at once. 631 * @param __fmtfl The new flags to set. 632 * @return The previous format control flags. 633 * 634 * This function overwrites all the format flags with @a __fmtfl. 635 */ 636 fmtflags 637 flags(fmtflags __fmtfl) 638 { 639 fmtflags __old = _M_flags; 640 _M_flags = __fmtfl; 641 return __old; 642 } 643 644 /** 645 * @brief Setting new format flags. 646 * @param __fmtfl Additional flags to set. 647 * @return The previous format control flags. 648 * 649 * This function sets additional flags in format control. Flags that 650 * were previously set remain set. 651 */ 652 fmtflags 653 setf(fmtflags __fmtfl) 654 { 655 fmtflags __old = _M_flags; 656 _M_flags |= __fmtfl; 657 return __old; 658 } 659 660 /** 661 * @brief Setting new format flags. 662 * @param __fmtfl Additional flags to set. 663 * @param __mask The flags mask for @a fmtfl. 664 * @return The previous format control flags. 665 * 666 * This function clears @a mask in the format flags, then sets 667 * @a fmtfl @c & @a mask. An example mask is @c ios_base::adjustfield. 668 */ 669 fmtflags 670 setf(fmtflags __fmtfl, fmtflags __mask) 671 { 672 fmtflags __old = _M_flags; 673 _M_flags &= ~__mask; 674 _M_flags |= (__fmtfl & __mask); 675 return __old; 676 } 677 678 /** 679 * @brief Clearing format flags. 680 * @param __mask The flags to unset. 681 * 682 * This function clears @a __mask in the format flags. 683 */ 684 void 685 unsetf(fmtflags __mask) 686 { _M_flags &= ~__mask; } 687 688 /** 689 * @brief Flags access. 690 * @return The precision to generate on certain output operations. 691 * 692 * Be careful if you try to give a definition of @a precision here; see 693 * DR 189. 694 */ 695 streamsize 696 precision() const 697 { return _M_precision; } 698 699 /** 700 * @brief Changing flags. 701 * @param __prec The new precision value. 702 * @return The previous value of precision(). 703 */ 704 streamsize 705 precision(streamsize __prec) 706 { 707 streamsize __old = _M_precision; 708 _M_precision = __prec; 709 return __old; 710 } 711 712 /** 713 * @brief Flags access. 714 * @return The minimum field width to generate on output operations. 715 * 716 * <em>Minimum field width</em> refers to the number of characters. 717 */ 718 streamsize 719 width() const 720 { return _M_width; } 721 722 /** 723 * @brief Changing flags. 724 * @param __wide The new width value. 725 * @return The previous value of width(). 726 */ 727 streamsize 728 width(streamsize __wide) 729 { 730 streamsize __old = _M_width; 731 _M_width = __wide; 732 return __old; 733 } 734 735 // [27.4.2.4] ios_base static members 736 /** 737 * @brief Interaction with the standard C I/O objects. 738 * @param __sync Whether to synchronize or not. 739 * @return True if the standard streams were previously synchronized. 740 * 741 * The synchronization referred to is @e only that between the standard 742 * C facilities (e.g., stdout) and the standard C++ objects (e.g., 743 * cout). User-declared streams are unaffected. See 744 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 745 */ 746 static bool 747 sync_with_stdio(bool __sync = true); 748 749 // [27.4.2.3] ios_base locale functions 750 /** 751 * @brief Setting a new locale. 752 * @param __loc The new locale. 753 * @return The previous locale. 754 * 755 * Sets the new locale for this stream, and then invokes each callback 756 * with imbue_event. 757 */ 758 locale 759 imbue(const locale& __loc) throw(); 760 761 /** 762 * @brief Locale access 763 * @return A copy of the current locale. 764 * 765 * If @c imbue(loc) has previously been called, then this function 766 * returns @c loc. Otherwise, it returns a copy of @c std::locale(), 767 * the global C++ locale. 768 */ 769 locale 770 getloc() const 771 { return _M_ios_locale; } 772 773 /** 774 * @brief Locale access 775 * @return A reference to the current locale. 776 * 777 * Like getloc above, but returns a reference instead of 778 * generating a copy. 779 */ 780 const locale& 781 _M_getloc() const 782 { return _M_ios_locale; } 783 784 // [27.4.2.5] ios_base storage functions 785 /** 786 * @brief Access to unique indices. 787 * @return An integer different from all previous calls. 788 * 789 * This function returns a unique integer every time it is called. It 790 * can be used for any purpose, but is primarily intended to be a unique 791 * index for the iword and pword functions. The expectation is that an 792 * application calls xalloc in order to obtain an index in the iword and 793 * pword arrays that can be used without fear of conflict. 794 * 795 * The implementation maintains a static variable that is incremented and 796 * returned on each invocation. xalloc is guaranteed to return an index 797 * that is safe to use in the iword and pword arrays. 798 */ 799 static int 800 xalloc() throw(); 801 802 /** 803 * @brief Access to integer array. 804 * @param __ix Index into the array. 805 * @return A reference to an integer associated with the index. 806 * 807 * The iword function provides access to an array of integers that can be 808 * used for any purpose. The array grows as required to hold the 809 * supplied index. All integers in the array are initialized to 0. 810 * 811 * The implementation reserves several indices. You should use xalloc to 812 * obtain an index that is safe to use. Also note that since the array 813 * can grow dynamically, it is not safe to hold onto the reference. 814 */ 815 long& 816 iword(int __ix) 817 { 818 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 819 ? _M_word[__ix] : _M_grow_words(__ix, true); 820 return __word._M_iword; 821 } 822 823 /** 824 * @brief Access to void pointer array. 825 * @param __ix Index into the array. 826 * @return A reference to a void* associated with the index. 827 * 828 * The pword function provides access to an array of pointers that can be 829 * used for any purpose. The array grows as required to hold the 830 * supplied index. All pointers in the array are initialized to 0. 831 * 832 * The implementation reserves several indices. You should use xalloc to 833 * obtain an index that is safe to use. Also note that since the array 834 * can grow dynamically, it is not safe to hold onto the reference. 835 */ 836 void*& 837 pword(int __ix) 838 { 839 _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size) 840 ? _M_word[__ix] : _M_grow_words(__ix, false); 841 return __word._M_pword; 842 } 843 844 // Destructor 845 /** 846 * Invokes each callback with erase_event. Destroys local storage. 847 * 848 * Note that the ios_base object for the standard streams never gets 849 * destroyed. As a result, any callbacks registered with the standard 850 * streams will not get invoked with erase_event (unless copyfmt is 851 * used). 852 */ 853 virtual ~ios_base(); 854 855 protected: 856 ios_base() throw (); 857 858 #if __cplusplus < 201103L 859 // _GLIBCXX_RESOLVE_LIB_DEFECTS 860 // 50. Copy constructor and assignment operator of ios_base 861 private: 862 ios_base(const ios_base&); 863 864 ios_base& 865 operator=(const ios_base&); 866 #else 867 public: 868 ios_base(const ios_base&) = delete; 869 870 ios_base& 871 operator=(const ios_base&) = delete; 872 873 protected: 874 void 875 _M_move(ios_base&) noexcept; 876 877 void 878 _M_swap(ios_base& __rhs) noexcept; 879 #endif 880 }; 881 882 // [27.4.5.1] fmtflags manipulators 883 /// Calls base.setf(ios_base::boolalpha). 884 inline ios_base& 885 boolalpha(ios_base& __base) 886 { 887 __base.setf(ios_base::boolalpha); 888 return __base; 889 } 890 891 /// Calls base.unsetf(ios_base::boolalpha). 892 inline ios_base& 893 noboolalpha(ios_base& __base) 894 { 895 __base.unsetf(ios_base::boolalpha); 896 return __base; 897 } 898 899 /// Calls base.setf(ios_base::showbase). 900 inline ios_base& 901 showbase(ios_base& __base) 902 { 903 __base.setf(ios_base::showbase); 904 return __base; 905 } 906 907 /// Calls base.unsetf(ios_base::showbase). 908 inline ios_base& 909 noshowbase(ios_base& __base) 910 { 911 __base.unsetf(ios_base::showbase); 912 return __base; 913 } 914 915 /// Calls base.setf(ios_base::showpoint). 916 inline ios_base& 917 showpoint(ios_base& __base) 918 { 919 __base.setf(ios_base::showpoint); 920 return __base; 921 } 922 923 /// Calls base.unsetf(ios_base::showpoint). 924 inline ios_base& 925 noshowpoint(ios_base& __base) 926 { 927 __base.unsetf(ios_base::showpoint); 928 return __base; 929 } 930 931 /// Calls base.setf(ios_base::showpos). 932 inline ios_base& 933 showpos(ios_base& __base) 934 { 935 __base.setf(ios_base::showpos); 936 return __base; 937 } 938 939 /// Calls base.unsetf(ios_base::showpos). 940 inline ios_base& 941 noshowpos(ios_base& __base) 942 { 943 __base.unsetf(ios_base::showpos); 944 return __base; 945 } 946 947 /// Calls base.setf(ios_base::skipws). 948 inline ios_base& 949 skipws(ios_base& __base) 950 { 951 __base.setf(ios_base::skipws); 952 return __base; 953 } 954 955 /// Calls base.unsetf(ios_base::skipws). 956 inline ios_base& 957 noskipws(ios_base& __base) 958 { 959 __base.unsetf(ios_base::skipws); 960 return __base; 961 } 962 963 /// Calls base.setf(ios_base::uppercase). 964 inline ios_base& 965 uppercase(ios_base& __base) 966 { 967 __base.setf(ios_base::uppercase); 968 return __base; 969 } 970 971 /// Calls base.unsetf(ios_base::uppercase). 972 inline ios_base& 973 nouppercase(ios_base& __base) 974 { 975 __base.unsetf(ios_base::uppercase); 976 return __base; 977 } 978 979 /// Calls base.setf(ios_base::unitbuf). 980 inline ios_base& 981 unitbuf(ios_base& __base) 982 { 983 __base.setf(ios_base::unitbuf); 984 return __base; 985 } 986 987 /// Calls base.unsetf(ios_base::unitbuf). 988 inline ios_base& 989 nounitbuf(ios_base& __base) 990 { 991 __base.unsetf(ios_base::unitbuf); 992 return __base; 993 } 994 995 // [27.4.5.2] adjustfield manipulators 996 /// Calls base.setf(ios_base::internal, ios_base::adjustfield). 997 inline ios_base& 998 internal(ios_base& __base) 999 { 1000 __base.setf(ios_base::internal, ios_base::adjustfield); 1001 return __base; 1002 } 1003 1004 /// Calls base.setf(ios_base::left, ios_base::adjustfield). 1005 inline ios_base& 1006 left(ios_base& __base) 1007 { 1008 __base.setf(ios_base::left, ios_base::adjustfield); 1009 return __base; 1010 } 1011 1012 /// Calls base.setf(ios_base::right, ios_base::adjustfield). 1013 inline ios_base& 1014 right(ios_base& __base) 1015 { 1016 __base.setf(ios_base::right, ios_base::adjustfield); 1017 return __base; 1018 } 1019 1020 // [27.4.5.3] basefield manipulators 1021 /// Calls base.setf(ios_base::dec, ios_base::basefield). 1022 inline ios_base& 1023 dec(ios_base& __base) 1024 { 1025 __base.setf(ios_base::dec, ios_base::basefield); 1026 return __base; 1027 } 1028 1029 /// Calls base.setf(ios_base::hex, ios_base::basefield). 1030 inline ios_base& 1031 hex(ios_base& __base) 1032 { 1033 __base.setf(ios_base::hex, ios_base::basefield); 1034 return __base; 1035 } 1036 1037 /// Calls base.setf(ios_base::oct, ios_base::basefield). 1038 inline ios_base& 1039 oct(ios_base& __base) 1040 { 1041 __base.setf(ios_base::oct, ios_base::basefield); 1042 return __base; 1043 } 1044 1045 // [27.4.5.4] floatfield manipulators 1046 /// Calls base.setf(ios_base::fixed, ios_base::floatfield). 1047 inline ios_base& 1048 fixed(ios_base& __base) 1049 { 1050 __base.setf(ios_base::fixed, ios_base::floatfield); 1051 return __base; 1052 } 1053 1054 /// Calls base.setf(ios_base::scientific, ios_base::floatfield). 1055 inline ios_base& 1056 scientific(ios_base& __base) 1057 { 1058 __base.setf(ios_base::scientific, ios_base::floatfield); 1059 return __base; 1060 } 1061 1062 #if __cplusplus >= 201103L 1063 // New C++11 floatfield manipulators 1064 1065 /// Calls 1066 /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield) 1067 inline ios_base& 1068 hexfloat(ios_base& __base) 1069 { 1070 __base.setf(ios_base::fixed | ios_base::scientific, ios_base::floatfield); 1071 return __base; 1072 } 1073 1074 /// Calls @c base.unsetf(ios_base::floatfield) 1075 inline ios_base& 1076 defaultfloat(ios_base& __base) 1077 { 1078 __base.unsetf(ios_base::floatfield); 1079 return __base; 1080 } 1081 #endif 1082 1083 _GLIBCXX_END_NAMESPACE_VERSION 1084 } // namespace 1085 1086 #endif /* _IOS_BASE_H */ 1087