1 // Input streams -*- C++ -*- 2 3 // Copyright (C) 1997-2014 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 // 26 // ISO C++ 14882: 27.6.1 Input streams 27 // 28 29 /** @file include/istream 30 * This is a Standard C++ Library header. 31 */ 32 33 #ifndef _GLIBCXX_ISTREAM 34 #define _GLIBCXX_ISTREAM 1 35 36 #pragma GCC system_header 37 38 #include <ios> 39 #include <ostream> 40 41 namespace std _GLIBCXX_VISIBILITY(default) 42 { 43 _GLIBCXX_BEGIN_NAMESPACE_VERSION 44 45 /** 46 * @brief Template class basic_istream. 47 * @ingroup io 48 * 49 * @tparam _CharT Type of character stream. 50 * @tparam _Traits Traits for character type, defaults to 51 * char_traits<_CharT>. 52 * 53 * This is the base class for all input streams. It provides text 54 * formatting of all builtin types, and communicates with any class 55 * derived from basic_streambuf to do the actual input. 56 */ 57 template<typename _CharT, typename _Traits> 58 class basic_istream : virtual public basic_ios<_CharT, _Traits> 59 { 60 public: 61 // Types (inherited from basic_ios (27.4.4)): 62 typedef _CharT char_type; 63 typedef typename _Traits::int_type int_type; 64 typedef typename _Traits::pos_type pos_type; 65 typedef typename _Traits::off_type off_type; 66 typedef _Traits traits_type; 67 68 // Non-standard Types: 69 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 70 typedef basic_ios<_CharT, _Traits> __ios_type; 71 typedef basic_istream<_CharT, _Traits> __istream_type; 72 typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > 73 __num_get_type; 74 typedef ctype<_CharT> __ctype_type; 75 76 protected: 77 // Data Members: 78 /** 79 * The number of characters extracted in the previous unformatted 80 * function; see gcount(). 81 */ 82 streamsize _M_gcount; 83 84 public: 85 /** 86 * @brief Base constructor. 87 * 88 * This ctor is almost never called by the user directly, rather from 89 * derived classes' initialization lists, which pass a pointer to 90 * their own stream buffer. 91 */ 92 explicit 93 basic_istream(__streambuf_type* __sb) 94 : _M_gcount(streamsize(0)) 95 { this->init(__sb); } 96 97 /** 98 * @brief Base destructor. 99 * 100 * This does very little apart from providing a virtual base dtor. 101 */ 102 virtual 103 ~basic_istream() 104 { _M_gcount = streamsize(0); } 105 106 /// Safe prefix/suffix operations. 107 class sentry; 108 friend class sentry; 109 110 //@{ 111 /** 112 * @brief Interface for manipulators. 113 * 114 * Manipulators such as @c std::ws and @c std::dec use these 115 * functions in constructs like 116 * <code>std::cin >> std::ws</code>. 117 * For more information, see the iomanip header. 118 */ 119 __istream_type& 120 operator>>(__istream_type& (*__pf)(__istream_type&)) 121 { return __pf(*this); } 122 123 __istream_type& 124 operator>>(__ios_type& (*__pf)(__ios_type&)) 125 { 126 __pf(*this); 127 return *this; 128 } 129 130 __istream_type& 131 operator>>(ios_base& (*__pf)(ios_base&)) 132 { 133 __pf(*this); 134 return *this; 135 } 136 //@} 137 138 //@{ 139 /** 140 * @name Extractors 141 * 142 * All the @c operator>> functions (aka <em>formatted input 143 * functions</em>) have some common behavior. Each starts by 144 * constructing a temporary object of type std::basic_istream::sentry 145 * with the second argument (noskipws) set to false. This has several 146 * effects, concluding with the setting of a status flag; see the 147 * sentry documentation for more. 148 * 149 * If the sentry status is good, the function tries to extract 150 * whatever data is appropriate for the type of the argument. 151 * 152 * If an exception is thrown during extraction, ios_base::badbit 153 * will be turned on in the stream's error state without causing an 154 * ios_base::failure to be thrown. The original exception will then 155 * be rethrown. 156 */ 157 158 //@{ 159 /** 160 * @brief Integer arithmetic extractors 161 * @param __n A variable of builtin integral type. 162 * @return @c *this if successful 163 * 164 * These functions use the stream's current locale (specifically, the 165 * @c num_get facet) to parse the input data. 166 */ 167 __istream_type& 168 operator>>(bool& __n) 169 { return _M_extract(__n); } 170 171 __istream_type& 172 operator>>(short& __n); 173 174 __istream_type& 175 operator>>(unsigned short& __n) 176 { return _M_extract(__n); } 177 178 __istream_type& 179 operator>>(int& __n); 180 181 __istream_type& 182 operator>>(unsigned int& __n) 183 { return _M_extract(__n); } 184 185 __istream_type& 186 operator>>(long& __n) 187 { return _M_extract(__n); } 188 189 __istream_type& 190 operator>>(unsigned long& __n) 191 { return _M_extract(__n); } 192 193 #ifdef _GLIBCXX_USE_LONG_LONG 194 __istream_type& 195 operator>>(long long& __n) 196 { return _M_extract(__n); } 197 198 __istream_type& 199 operator>>(unsigned long long& __n) 200 { return _M_extract(__n); } 201 #endif 202 //@} 203 204 //@{ 205 /** 206 * @brief Floating point arithmetic extractors 207 * @param __f A variable of builtin floating point type. 208 * @return @c *this if successful 209 * 210 * These functions use the stream's current locale (specifically, the 211 * @c num_get facet) to parse the input data. 212 */ 213 __istream_type& 214 operator>>(float& __f) 215 { return _M_extract(__f); } 216 217 __istream_type& 218 operator>>(double& __f) 219 { return _M_extract(__f); } 220 221 __istream_type& 222 operator>>(long double& __f) 223 { return _M_extract(__f); } 224 //@} 225 226 /** 227 * @brief Basic arithmetic extractors 228 * @param __p A variable of pointer type. 229 * @return @c *this if successful 230 * 231 * These functions use the stream's current locale (specifically, the 232 * @c num_get facet) to parse the input data. 233 */ 234 __istream_type& 235 operator>>(void*& __p) 236 { return _M_extract(__p); } 237 238 /** 239 * @brief Extracting into another streambuf. 240 * @param __sb A pointer to a streambuf 241 * 242 * This function behaves like one of the basic arithmetic extractors, 243 * in that it also constructs a sentry object and has the same error 244 * handling behavior. 245 * 246 * If @p __sb is NULL, the stream will set failbit in its error state. 247 * 248 * Characters are extracted from this stream and inserted into the 249 * @p __sb streambuf until one of the following occurs: 250 * 251 * - the input stream reaches end-of-file, 252 * - insertion into the output buffer fails (in this case, the 253 * character that would have been inserted is not extracted), or 254 * - an exception occurs (and in this case is caught) 255 * 256 * If the function inserts no characters, failbit is set. 257 */ 258 __istream_type& 259 operator>>(__streambuf_type* __sb); 260 //@} 261 262 // [27.6.1.3] unformatted input 263 /** 264 * @brief Character counting 265 * @return The number of characters extracted by the previous 266 * unformatted input function dispatched for this stream. 267 */ 268 streamsize 269 gcount() const 270 { return _M_gcount; } 271 272 //@{ 273 /** 274 * @name Unformatted Input Functions 275 * 276 * All the unformatted input functions have some common behavior. 277 * Each starts by constructing a temporary object of type 278 * std::basic_istream::sentry with the second argument (noskipws) 279 * set to true. This has several effects, concluding with the 280 * setting of a status flag; see the sentry documentation for more. 281 * 282 * If the sentry status is good, the function tries to extract 283 * whatever data is appropriate for the type of the argument. 284 * 285 * The number of characters extracted is stored for later retrieval 286 * by gcount(). 287 * 288 * If an exception is thrown during extraction, ios_base::badbit 289 * will be turned on in the stream's error state without causing an 290 * ios_base::failure to be thrown. The original exception will then 291 * be rethrown. 292 */ 293 294 /** 295 * @brief Simple extraction. 296 * @return A character, or eof(). 297 * 298 * Tries to extract a character. If none are available, sets failbit 299 * and returns traits::eof(). 300 */ 301 int_type 302 get(); 303 304 /** 305 * @brief Simple extraction. 306 * @param __c The character in which to store data. 307 * @return *this 308 * 309 * Tries to extract a character and store it in @a __c. If none are 310 * available, sets failbit and returns traits::eof(). 311 * 312 * @note This function is not overloaded on signed char and 313 * unsigned char. 314 */ 315 __istream_type& 316 get(char_type& __c); 317 318 /** 319 * @brief Simple multiple-character extraction. 320 * @param __s Pointer to an array. 321 * @param __n Maximum number of characters to store in @a __s. 322 * @param __delim A "stop" character. 323 * @return *this 324 * 325 * Characters are extracted and stored into @a __s until one of the 326 * following happens: 327 * 328 * - @c __n-1 characters are stored 329 * - the input sequence reaches EOF 330 * - the next character equals @a __delim, in which case the character 331 * is not extracted 332 * 333 * If no characters are stored, failbit is set in the stream's error 334 * state. 335 * 336 * In any case, a null character is stored into the next location in 337 * the array. 338 * 339 * @note This function is not overloaded on signed char and 340 * unsigned char. 341 */ 342 __istream_type& 343 get(char_type* __s, streamsize __n, char_type __delim); 344 345 /** 346 * @brief Simple multiple-character extraction. 347 * @param __s Pointer to an array. 348 * @param __n Maximum number of characters to store in @a s. 349 * @return *this 350 * 351 * Returns @c get(__s,__n,widen('\\n')). 352 */ 353 __istream_type& 354 get(char_type* __s, streamsize __n) 355 { return this->get(__s, __n, this->widen('\n')); } 356 357 /** 358 * @brief Extraction into another streambuf. 359 * @param __sb A streambuf in which to store data. 360 * @param __delim A "stop" character. 361 * @return *this 362 * 363 * Characters are extracted and inserted into @a __sb until one of the 364 * following happens: 365 * 366 * - the input sequence reaches EOF 367 * - insertion into the output buffer fails (in this case, the 368 * character that would have been inserted is not extracted) 369 * - the next character equals @a __delim (in this case, the character 370 * is not extracted) 371 * - an exception occurs (and in this case is caught) 372 * 373 * If no characters are stored, failbit is set in the stream's error 374 * state. 375 */ 376 __istream_type& 377 get(__streambuf_type& __sb, char_type __delim); 378 379 /** 380 * @brief Extraction into another streambuf. 381 * @param __sb A streambuf in which to store data. 382 * @return *this 383 * 384 * Returns @c get(__sb,widen('\\n')). 385 */ 386 __istream_type& 387 get(__streambuf_type& __sb) 388 { return this->get(__sb, this->widen('\n')); } 389 390 /** 391 * @brief String extraction. 392 * @param __s A character array in which to store the data. 393 * @param __n Maximum number of characters to extract. 394 * @param __delim A "stop" character. 395 * @return *this 396 * 397 * Extracts and stores characters into @a __s until one of the 398 * following happens. Note that these criteria are required to be 399 * tested in the order listed here, to allow an input line to exactly 400 * fill the @a __s array without setting failbit. 401 * 402 * -# the input sequence reaches end-of-file, in which case eofbit 403 * is set in the stream error state 404 * -# the next character equals @c __delim, in which case the character 405 * is extracted (and therefore counted in @c gcount()) but not stored 406 * -# @c __n-1 characters are stored, in which case failbit is set 407 * in the stream error state 408 * 409 * If no characters are extracted, failbit is set. (An empty line of 410 * input should therefore not cause failbit to be set.) 411 * 412 * In any case, a null character is stored in the next location in 413 * the array. 414 */ 415 __istream_type& 416 getline(char_type* __s, streamsize __n, char_type __delim); 417 418 /** 419 * @brief String extraction. 420 * @param __s A character array in which to store the data. 421 * @param __n Maximum number of characters to extract. 422 * @return *this 423 * 424 * Returns @c getline(__s,__n,widen('\\n')). 425 */ 426 __istream_type& 427 getline(char_type* __s, streamsize __n) 428 { return this->getline(__s, __n, this->widen('\n')); } 429 430 /** 431 * @brief Discarding characters 432 * @param __n Number of characters to discard. 433 * @param __delim A "stop" character. 434 * @return *this 435 * 436 * Extracts characters and throws them away until one of the 437 * following happens: 438 * - if @a __n @c != @c std::numeric_limits<int>::max(), @a __n 439 * characters are extracted 440 * - the input sequence reaches end-of-file 441 * - the next character equals @a __delim (in this case, the character 442 * is extracted); note that this condition will never occur if 443 * @a __delim equals @c traits::eof(). 444 * 445 * NB: Provide three overloads, instead of the single function 446 * (with defaults) mandated by the Standard: this leads to a 447 * better performing implementation, while still conforming to 448 * the Standard. 449 */ 450 __istream_type& 451 ignore(streamsize __n, int_type __delim); 452 453 __istream_type& 454 ignore(streamsize __n); 455 456 __istream_type& 457 ignore(); 458 459 /** 460 * @brief Looking ahead in the stream 461 * @return The next character, or eof(). 462 * 463 * If, after constructing the sentry object, @c good() is false, 464 * returns @c traits::eof(). Otherwise reads but does not extract 465 * the next input character. 466 */ 467 int_type 468 peek(); 469 470 /** 471 * @brief Extraction without delimiters. 472 * @param __s A character array. 473 * @param __n Maximum number of characters to store. 474 * @return *this 475 * 476 * If the stream state is @c good(), extracts characters and stores 477 * them into @a __s until one of the following happens: 478 * - @a __n characters are stored 479 * - the input sequence reaches end-of-file, in which case the error 480 * state is set to @c failbit|eofbit. 481 * 482 * @note This function is not overloaded on signed char and 483 * unsigned char. 484 */ 485 __istream_type& 486 read(char_type* __s, streamsize __n); 487 488 /** 489 * @brief Extraction until the buffer is exhausted, but no more. 490 * @param __s A character array. 491 * @param __n Maximum number of characters to store. 492 * @return The number of characters extracted. 493 * 494 * Extracts characters and stores them into @a __s depending on the 495 * number of characters remaining in the streambuf's buffer, 496 * @c rdbuf()->in_avail(), called @c A here: 497 * - if @c A @c == @c -1, sets eofbit and extracts no characters 498 * - if @c A @c == @c 0, extracts no characters 499 * - if @c A @c > @c 0, extracts @c min(A,n) 500 * 501 * The goal is to empty the current buffer, and to not request any 502 * more from the external input sequence controlled by the streambuf. 503 */ 504 streamsize 505 readsome(char_type* __s, streamsize __n); 506 507 /** 508 * @brief Unextracting a single character. 509 * @param __c The character to push back into the input stream. 510 * @return *this 511 * 512 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 513 * 514 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 515 * the error state. 516 * 517 * @note This function first clears eofbit. Since no characters 518 * are extracted, the next call to @c gcount() will return 0, 519 * as required by DR 60. 520 */ 521 __istream_type& 522 putback(char_type __c); 523 524 /** 525 * @brief Unextracting the previous character. 526 * @return *this 527 * 528 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 529 * 530 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 531 * the error state. 532 * 533 * @note This function first clears eofbit. Since no characters 534 * are extracted, the next call to @c gcount() will return 0, 535 * as required by DR 60. 536 */ 537 __istream_type& 538 unget(); 539 540 /** 541 * @brief Synchronizing the stream buffer. 542 * @return 0 on success, -1 on failure 543 * 544 * If @c rdbuf() is a null pointer, returns -1. 545 * 546 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 547 * sets badbit and returns -1. 548 * 549 * Otherwise, returns 0. 550 * 551 * @note This function does not count the number of characters 552 * extracted, if any, and therefore does not affect the next 553 * call to @c gcount(). 554 */ 555 int 556 sync(); 557 558 /** 559 * @brief Getting the current read position. 560 * @return A file position object. 561 * 562 * If @c fail() is not false, returns @c pos_type(-1) to indicate 563 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 564 * 565 * @note This function does not count the number of characters 566 * extracted, if any, and therefore does not affect the next 567 * call to @c gcount(). At variance with putback, unget and 568 * seekg, eofbit is not cleared first. 569 */ 570 pos_type 571 tellg(); 572 573 /** 574 * @brief Changing the current read position. 575 * @param __pos A file position object. 576 * @return *this 577 * 578 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(__pos). If 579 * that function fails, sets failbit. 580 * 581 * @note This function first clears eofbit. It does not count the 582 * number of characters extracted, if any, and therefore does 583 * not affect the next call to @c gcount(). 584 */ 585 __istream_type& 586 seekg(pos_type); 587 588 /** 589 * @brief Changing the current read position. 590 * @param __off A file offset object. 591 * @param __dir The direction in which to seek. 592 * @return *this 593 * 594 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(__off,__dir). 595 * If that function fails, sets failbit. 596 * 597 * @note This function first clears eofbit. It does not count the 598 * number of characters extracted, if any, and therefore does 599 * not affect the next call to @c gcount(). 600 */ 601 __istream_type& 602 seekg(off_type, ios_base::seekdir); 603 //@} 604 605 protected: 606 basic_istream() 607 : _M_gcount(streamsize(0)) 608 { this->init(0); } 609 610 template<typename _ValueT> 611 __istream_type& 612 _M_extract(_ValueT& __v); 613 }; 614 615 /// Explicit specialization declarations, defined in src/istream.cc. 616 template<> 617 basic_istream<char>& 618 basic_istream<char>:: 619 getline(char_type* __s, streamsize __n, char_type __delim); 620 621 template<> 622 basic_istream<char>& 623 basic_istream<char>:: 624 ignore(streamsize __n); 625 626 template<> 627 basic_istream<char>& 628 basic_istream<char>:: 629 ignore(streamsize __n, int_type __delim); 630 631 #ifdef _GLIBCXX_USE_WCHAR_T 632 template<> 633 basic_istream<wchar_t>& 634 basic_istream<wchar_t>:: 635 getline(char_type* __s, streamsize __n, char_type __delim); 636 637 template<> 638 basic_istream<wchar_t>& 639 basic_istream<wchar_t>:: 640 ignore(streamsize __n); 641 642 template<> 643 basic_istream<wchar_t>& 644 basic_istream<wchar_t>:: 645 ignore(streamsize __n, int_type __delim); 646 #endif 647 648 /** 649 * @brief Performs setup work for input streams. 650 * 651 * Objects of this class are created before all of the standard 652 * extractors are run. It is responsible for <em>exception-safe 653 * prefix and suffix operations,</em> although only prefix actions 654 * are currently required by the standard. 655 */ 656 template<typename _CharT, typename _Traits> 657 class basic_istream<_CharT, _Traits>::sentry 658 { 659 // Data Members. 660 bool _M_ok; 661 662 public: 663 /// Easy access to dependent types. 664 typedef _Traits traits_type; 665 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 666 typedef basic_istream<_CharT, _Traits> __istream_type; 667 typedef typename __istream_type::__ctype_type __ctype_type; 668 typedef typename _Traits::int_type __int_type; 669 670 /** 671 * @brief The constructor performs all the work. 672 * @param __is The input stream to guard. 673 * @param __noskipws Whether to consume whitespace or not. 674 * 675 * If the stream state is good (@a __is.good() is true), then the 676 * following actions are performed, otherwise the sentry state 677 * is false (<em>not okay</em>) and failbit is set in the 678 * stream state. 679 * 680 * The sentry's preparatory actions are: 681 * 682 * -# if the stream is tied to an output stream, @c is.tie()->flush() 683 * is called to synchronize the output sequence 684 * -# if @a __noskipws is false, and @c ios_base::skipws is set in 685 * @c is.flags(), the sentry extracts and discards whitespace 686 * characters from the stream. The currently imbued locale is 687 * used to determine whether each character is whitespace. 688 * 689 * If the stream state is still good, then the sentry state becomes 690 * true (@a okay). 691 */ 692 explicit 693 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 694 695 /** 696 * @brief Quick status checking. 697 * @return The sentry state. 698 * 699 * For ease of use, sentries may be converted to booleans. The 700 * return value is that of the sentry state (true == okay). 701 */ 702 #if __cplusplus >= 201103L 703 explicit 704 #endif 705 operator bool() const 706 { return _M_ok; } 707 }; 708 709 //@{ 710 /** 711 * @brief Character extractors 712 * @param __in An input stream. 713 * @param __c A character reference. 714 * @return in 715 * 716 * Behaves like one of the formatted arithmetic extractors described in 717 * std::basic_istream. After constructing a sentry object with good 718 * status, this function extracts a character (if one is available) and 719 * stores it in @a __c. Otherwise, sets failbit in the input stream. 720 */ 721 template<typename _CharT, typename _Traits> 722 basic_istream<_CharT, _Traits>& 723 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 724 725 template<class _Traits> 726 inline basic_istream<char, _Traits>& 727 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 728 { return (__in >> reinterpret_cast<char&>(__c)); } 729 730 template<class _Traits> 731 inline basic_istream<char, _Traits>& 732 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 733 { return (__in >> reinterpret_cast<char&>(__c)); } 734 //@} 735 736 //@{ 737 /** 738 * @brief Character string extractors 739 * @param __in An input stream. 740 * @param __s A pointer to a character array. 741 * @return __in 742 * 743 * Behaves like one of the formatted arithmetic extractors described in 744 * std::basic_istream. After constructing a sentry object with good 745 * status, this function extracts up to @c n characters and stores them 746 * into the array starting at @a __s. @c n is defined as: 747 * 748 * - if @c width() is greater than zero, @c n is width() otherwise 749 * - @c n is <em>the number of elements of the largest array of * 750 * - @c char_type that can store a terminating @c eos.</em> 751 * - [27.6.1.2.3]/6 752 * 753 * Characters are extracted and stored until one of the following happens: 754 * - @c n-1 characters are stored 755 * - EOF is reached 756 * - the next character is whitespace according to the current locale 757 * - the next character is a null byte (i.e., @c charT() ) 758 * 759 * @c width(0) is then called for the input stream. 760 * 761 * If no characters are extracted, sets failbit. 762 */ 763 template<typename _CharT, typename _Traits> 764 basic_istream<_CharT, _Traits>& 765 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 766 767 // Explicit specialization declaration, defined in src/istream.cc. 768 template<> 769 basic_istream<char>& 770 operator>>(basic_istream<char>& __in, char* __s); 771 772 template<class _Traits> 773 inline basic_istream<char, _Traits>& 774 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 775 { return (__in >> reinterpret_cast<char*>(__s)); } 776 777 template<class _Traits> 778 inline basic_istream<char, _Traits>& 779 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 780 { return (__in >> reinterpret_cast<char*>(__s)); } 781 //@} 782 783 /** 784 * @brief Template class basic_iostream 785 * @ingroup io 786 * 787 * @tparam _CharT Type of character stream. 788 * @tparam _Traits Traits for character type, defaults to 789 * char_traits<_CharT>. 790 * 791 * This class multiply inherits from the input and output stream classes 792 * simply to provide a single interface. 793 */ 794 template<typename _CharT, typename _Traits> 795 class basic_iostream 796 : public basic_istream<_CharT, _Traits>, 797 public basic_ostream<_CharT, _Traits> 798 { 799 public: 800 // _GLIBCXX_RESOLVE_LIB_DEFECTS 801 // 271. basic_iostream missing typedefs 802 // Types (inherited): 803 typedef _CharT char_type; 804 typedef typename _Traits::int_type int_type; 805 typedef typename _Traits::pos_type pos_type; 806 typedef typename _Traits::off_type off_type; 807 typedef _Traits traits_type; 808 809 // Non-standard Types: 810 typedef basic_istream<_CharT, _Traits> __istream_type; 811 typedef basic_ostream<_CharT, _Traits> __ostream_type; 812 813 /** 814 * @brief Constructor does nothing. 815 * 816 * Both of the parent classes are initialized with the same 817 * streambuf pointer passed to this constructor. 818 */ 819 explicit 820 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 821 : __istream_type(__sb), __ostream_type(__sb) { } 822 823 /** 824 * @brief Destructor does nothing. 825 */ 826 virtual 827 ~basic_iostream() { } 828 829 protected: 830 basic_iostream() 831 : __istream_type(), __ostream_type() { } 832 }; 833 834 /** 835 * @brief Quick and easy way to eat whitespace 836 * 837 * This manipulator extracts whitespace characters, stopping when the 838 * next character is non-whitespace, or when the input sequence is empty. 839 * If the sequence is empty, @c eofbit is set in the stream, but not 840 * @c failbit. 841 * 842 * The current locale is used to distinguish whitespace characters. 843 * 844 * Example: 845 * @code 846 * MyClass mc; 847 * 848 * std::cin >> std::ws >> mc; 849 * @endcode 850 * will skip leading whitespace before calling operator>> on cin and your 851 * object. Note that the same effect can be achieved by creating a 852 * std::basic_istream::sentry inside your definition of operator>>. 853 */ 854 template<typename _CharT, typename _Traits> 855 basic_istream<_CharT, _Traits>& 856 ws(basic_istream<_CharT, _Traits>& __is); 857 858 #if __cplusplus >= 201103L 859 // [27.7.1.6] Rvalue stream extraction 860 /** 861 * @brief Generic extractor for rvalue stream 862 * @param __is An input stream. 863 * @param __x A reference to the extraction target. 864 * @return is 865 * 866 * This is just a forwarding function to allow extraction from 867 * rvalue streams since they won't bind to the extractor functions 868 * that take an lvalue reference. 869 */ 870 template<typename _CharT, typename _Traits, typename _Tp> 871 inline basic_istream<_CharT, _Traits>& 872 operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) 873 { return (__is >> __x); } 874 #endif // C++11 875 876 _GLIBCXX_END_NAMESPACE_VERSION 877 } // namespace 878 879 #include <bits/istream.tcc> 880 881 #endif /* _GLIBCXX_ISTREAM */ 882
