std_istream.h revision 132720
180709Sjake// Input streams -*- C++ -*- 280709Sjake 380709Sjake// Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003 480709Sjake// Free Software Foundation, Inc. 580709Sjake// 680709Sjake// This file is part of the GNU ISO C++ Library. This library is free 780709Sjake// software; you can redistribute it and/or modify it under the 880709Sjake// terms of the GNU General Public License as published by the 980709Sjake// Free Software Foundation; either version 2, or (at your option) 1080709Sjake// any later version. 1180709Sjake 1280709Sjake// This library is distributed in the hope that it will be useful, 1380709Sjake// but WITHOUT ANY WARRANTY; without even the implied warranty of 1481337Sobrien// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 1580709Sjake// GNU General Public License for more details. 1680709Sjake 1781337Sobrien// You should have received a copy of the GNU General Public License along 1880709Sjake// with this library; see the file COPYING. If not, write to the Free 1980709Sjake// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 2080709Sjake// USA. 2180709Sjake 2280709Sjake// As a special exception, you may use this file as part of a free software 2380709Sjake// library without restriction. Specifically, if other files instantiate 2480709Sjake// templates or use macros or inline functions from this file, or you compile 2580709Sjake// this file and link it with other files to produce an executable, this 2680709Sjake// file does not by itself cause the resulting executable to be covered by 2780709Sjake// the GNU General Public License. This exception does not however 2880709Sjake// invalidate any other reasons why the executable file might be covered by 2980709Sjake// the GNU General Public License. 3080709Sjake 3180709Sjake// 3280709Sjake// ISO C++ 14882: 27.6.1 Input streams 3382910Sjake// 3480709Sjake 3580709Sjake/** @file istream 3680709Sjake * This is a Standard C++ Library header. You should @c #include this header 3784186Sjake * in your programs, rather than any of the "st[dl]_*.h" implementation files. 3880709Sjake */ 3980709Sjake 4081381Sjake#ifndef _GLIBCXX_ISTREAM 4181381Sjake#define _GLIBCXX_ISTREAM 1 4281381Sjake 4381381Sjake#pragma GCC system_header 4480709Sjake 4580709Sjake#include <ios> 4680709Sjake#include <limits> // For numeric_limits 4780709Sjake 4881135Stmmnamespace std 4980709Sjake{ 5080709Sjake // [27.6.1.1] Template class basic_istream 5181614Sjake /** 5280709Sjake * @brief Controlling input. 5380709Sjake * 5480709Sjake * This is the base class for all input streams. It provides text 5582910Sjake * formatting of all builtin types, and communicates with any class 5680709Sjake * derived from basic_streambuf to do the actual input. 5780709Sjake */ 5880709Sjake template<typename _CharT, typename _Traits> 5980709Sjake class basic_istream : virtual public basic_ios<_CharT, _Traits> 6082010Sjake { 6180709Sjake public: 6283756Sjake // Types (inherited from basic_ios (27.4.4)): 6383756Sjake typedef _CharT char_type; 6480709Sjake typedef typename _Traits::int_type int_type; 6580709Sjake typedef typename _Traits::pos_type pos_type; 6680709Sjake typedef typename _Traits::off_type off_type; 6783366Sjulian typedef _Traits traits_type; 6884186Sjake 6983366Sjulian // Non-standard Types: 7080709Sjake typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 7180709Sjake typedef basic_ios<_CharT, _Traits> __ios_type; 7282910Sjake typedef basic_istream<_CharT, _Traits> __istream_type; 7380709Sjake typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > 7481135Stmm __num_get_type; 7581135Stmm typedef ctype<_CharT> __ctype_type; 7681135Stmm 7781135Stmm template<typename _CharT2, typename _Traits2> 7881381Sjake friend basic_istream<_CharT2, _Traits2>& 7981381Sjake operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2&); 8081381Sjake 8181381Sjake template<typename _CharT2, typename _Traits2> 8280709Sjake friend basic_istream<_CharT2, _Traits2>& 8381381Sjake operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*); 8481381Sjake 8581381Sjake protected: 8680709Sjake // Data Members: 8785244Sjake /** 8880709Sjake * @if maint 8980709Sjake * The number of characters extracted in the previous unformatted 9080709Sjake * function; see gcount(). 9180709Sjake * @endif 9282910Sjake */ 9385244Sjake streamsize _M_gcount; 9484186Sjake 9584186Sjake public: 9684186Sjake // [27.6.1.1.1] constructor/destructor 9782910Sjake /** 9885244Sjake * @brief Base constructor. 9985244Sjake * 10085244Sjake * This ctor is almost never called by the user directly, rather from 10182910Sjake * derived classes' initialization lists, which pass a pointer to 10282910Sjake * their own stream buffer. 10382910Sjake */ 10482910Sjake explicit 10582910Sjake basic_istream(__streambuf_type* __sb): _M_gcount(streamsize(0)) 10682910Sjake { this->init(__sb); } 10782910Sjake 10882910Sjake /** 10982910Sjake * @brief Base destructor. 11080709Sjake * 11180709Sjake * This does very little apart from providing a virtual base dtor. 11281381Sjake */ 11380709Sjake virtual 11481381Sjake ~basic_istream() 11580709Sjake { _M_gcount = streamsize(0); } 11680709Sjake 11780709Sjake // [27.6.1.1.2] prefix/suffix 11880709Sjake class sentry; 11981614Sjake friend class sentry; 12081381Sjake 12180709Sjake // [27.6.1.2] formatted input 12280709Sjake // [27.6.1.2.3] basic_istream::operator>> 12380709Sjake //@{ 12480709Sjake /** 12580709Sjake * @brief Interface for manipulators. 12680709Sjake * 12780709Sjake * Manuipulators such as @c std::ws and @c std::dec use these 12884186Sjake * functions in constructs like "std::cin >> std::ws". For more 12984186Sjake * information, see the iomanip header. 13083366Sjulian */ 13180709Sjake inline __istream_type& 13282910Sjake operator>>(__istream_type& (*__pf)(__istream_type&)); 13380709Sjake 13484186Sjake inline __istream_type& 13584186Sjake operator>>(__ios_type& (*__pf)(__ios_type&)); 13684186Sjake 13781614Sjake inline __istream_type& 13881614Sjake operator>>(ios_base& (*__pf)(ios_base&)); 13981614Sjake //@} 14081614Sjake 14181614Sjake // [27.6.1.2.2] arithmetic extractors 14281614Sjake /** 14381614Sjake * @name Arithmetic Extractors 14481614Sjake * 14581614Sjake * All the @c operator>> functions (aka <em>formatted input 14681614Sjake * functions</em>) have some common behavior. Each starts by 14781614Sjake * constructing a temporary object of type std::basic_istream::sentry 14881614Sjake * with the second argument (noskipws) set to false. This has several 14981614Sjake * effects, concluding with the setting of a status flag; see the 15081614Sjake * sentry documentation for more. 15181614Sjake * 15281614Sjake * If the sentry status is good, the function tries to extract 15385244Sjake * whatever data is appropriate for the type of the argument. 15485244Sjake * 15580709Sjake * If an exception is thrown during extraction, ios_base::badbit 15680709Sjake * will be turned on in the stream's error state without causing an 15780709Sjake * ios_base::failure to be thrown. The original exception will then 15880709Sjake * be rethrown. 15983366Sjulian */ 16083366Sjulian //@{ 16182910Sjake /** 16282910Sjake * @brief Basic arithmetic extractors 16382910Sjake * @param A variable of builtin type. 16480709Sjake * @return @c *this if successful 16580709Sjake * 16683366Sjulian * These functions use the stream's current locale (specifically, the 16783366Sjulian * @c num_get facet) to parse the input data. 16883366Sjulian */ 16983366Sjulian __istream_type& 17083366Sjulian operator>>(bool& __n); 17183366Sjulian 17283366Sjulian __istream_type& 17383366Sjulian operator>>(short& __n); 17484186Sjake 17581135Stmm __istream_type& 17680709Sjake operator>>(unsigned short& __n); 17780709Sjake 17882010Sjake __istream_type& 17980709Sjake operator>>(int& __n); 18082010Sjake 18182910Sjake __istream_type& 18282910Sjake operator>>(unsigned int& __n); 18382910Sjake 18480709Sjake __istream_type& 18581381Sjake operator>>(long& __n); 18681381Sjake 18781381Sjake __istream_type& 18881381Sjake operator>>(unsigned long& __n); 18981135Stmm 19081135Stmm#ifdef _GLIBCXX_USE_LONG_LONG 19181135Stmm __istream_type& 19281135Stmm operator>>(long long& __n); 19381135Stmm 19481135Stmm __istream_type& 19581135Stmm operator>>(unsigned long long& __n); 19680709Sjake#endif 19780709Sjake 19880709Sjake __istream_type& 19982910Sjake operator>>(float& __f); 20082010Sjake 20180709Sjake __istream_type& 20280709Sjake operator>>(double& __f); 20380709Sjake 20480709Sjake __istream_type& 20580709Sjake operator>>(long double& __f); 20680709Sjake 20780709Sjake __istream_type& 20880709Sjake operator>>(void*& __p); 20980709Sjake 21080709Sjake /** 21180709Sjake * @brief Extracting into another streambuf. 21280709Sjake * @param sb A pointer to a streambuf 21380709Sjake * 21480709Sjake * This function behaves like one of the basic arithmetic extractors, 21580709Sjake * in that it also constructs a sentry object and has the same error 21680709Sjake * handling behavior. 21780709Sjake * 21880709Sjake * If @a sb is NULL, the stream will set failbit in its error state. 21980709Sjake * 22080709Sjake * Characters are extracted from this stream and inserted into the 22180709Sjake * @a sb streambuf until one of the following occurs: 22280709Sjake * 22380709Sjake * - the input stream reaches end-of-file, 22480709Sjake * - insertion into the output buffer fails (in this case, the 22582910Sjake * character that would have been inserted is not extracted), or 22681614Sjake * - an exception occurs (and in this case is caught) 22780709Sjake * 22880709Sjake * If the function inserts no characters, failbit is set. 22980709Sjake */ 23080709Sjake __istream_type& 23182910Sjake operator>>(__streambuf_type* __sb); 23280709Sjake //@} 23380709Sjake 234 // [27.6.1.3] unformatted input 235 /** 236 * @brief Character counting 237 * @return The number of characters extracted by the previous 238 * unformatted input function dispatched for this stream. 239 */ 240 inline streamsize 241 gcount() const 242 { return _M_gcount; } 243 244 /** 245 * @name Unformatted Input Functions 246 * 247 * All the unformatted input functions have some common behavior. 248 * Each starts by constructing a temporary object of type 249 * std::basic_istream::sentry with the second argument (noskipws) 250 * set to true. This has several effects, concluding with the 251 * setting of a status flag; see the sentry documentation for more. 252 * 253 * If the sentry status is good, the function tries to extract 254 * whatever data is appropriate for the type of the argument. 255 * 256 * The number of characters extracted is stored for later retrieval 257 * by gcount(). 258 * 259 * If an exception is thrown during extraction, ios_base::badbit 260 * will be turned on in the stream's error state without causing an 261 * ios_base::failure to be thrown. The original exception will then 262 * be rethrown. 263 */ 264 //@{ 265 /** 266 * @brief Simple extraction. 267 * @return A character, or eof(). 268 * 269 * Tries to extract a character. If none are available, sets failbit 270 * and returns traits::eof(). 271 */ 272 int_type 273 get(); 274 275 /** 276 * @brief Simple extraction. 277 * @param c The character in which to store data. 278 * @return *this 279 * 280 * Tries to extract a character and store it in @a c. If none are 281 * available, sets failbit and returns traits::eof(). 282 * 283 * @note This function is not overloaded on signed char and 284 * unsigned char. 285 */ 286 __istream_type& 287 get(char_type& __c); 288 289 /** 290 * @brief Simple multiple-character extraction. 291 * @param s Pointer to an array. 292 * @param n Maximum number of characters to store in @a s. 293 * @param delim A "stop" character. 294 * @return *this 295 * 296 * Characters are extracted and stored into @a s until one of the 297 * following happens: 298 * 299 * - @c n-1 characters are stored 300 * - the input sequence reaches EOF 301 * - the next character equals @a delim, in which case the character 302 * is not extracted 303 * 304 * If no characters are stored, failbit is set in the stream's error 305 * state. 306 * 307 * In any case, a null character is stored into the next location in 308 * the array. 309 * 310 * @note This function is not overloaded on signed char and 311 * unsigned char. 312 */ 313 __istream_type& 314 get(char_type* __s, streamsize __n, char_type __delim); 315 316 /** 317 * @brief Simple multiple-character extraction. 318 * @param s Pointer to an array. 319 * @param n Maximum number of characters to store in @a s. 320 * @return *this 321 * 322 * Returns @c get(s,n,widen('\n')). 323 */ 324 inline __istream_type& 325 get(char_type* __s, streamsize __n) 326 { return this->get(__s, __n, this->widen('\n')); } 327 328 /** 329 * @brief Extraction into another streambuf. 330 * @param sb A streambuf in which to store data. 331 * @param delim A "stop" character. 332 * @return *this 333 * 334 * Characters are extracted and inserted into @a sb until one of the 335 * following happens: 336 * 337 * - the input sequence reaches EOF 338 * - insertion into the output buffer fails (in this case, the 339 * character that would have been inserted is not extracted) 340 * - the next character equals @a delim (in this case, the character 341 * is not extracted) 342 * - an exception occurs (and in this case is caught) 343 * 344 * If no characters are stored, failbit is set in the stream's error 345 * state. 346 */ 347 __istream_type& 348 get(__streambuf_type& __sb, char_type __delim); 349 350 /** 351 * @brief Extraction into another streambuf. 352 * @param sb A streambuf in which to store data. 353 * @return *this 354 * 355 * Returns @c get(sb,widen('\n')). 356 */ 357 inline __istream_type& 358 get(__streambuf_type& __sb) 359 { return this->get(__sb, this->widen('\n')); } 360 361 /** 362 * @brief String extraction. 363 * @param s A character array in which to store the data. 364 * @param n Maximum number of characters to extract. 365 * @param delim A "stop" character. 366 * @return *this 367 * 368 * Extracts and stores characters into @a s until one of the 369 * following happens. Note that these criteria are required to be 370 * tested in the order listed here, to allow an input line to exactly 371 * fill the @a s array without setting failbit. 372 * 373 * -# the input sequence reaches end-of-file, in which case eofbit 374 * is set in the stream error state 375 * -# the next character equals @c delim, in which case the character 376 * is extracted (and therefore counted in @c gcount()) but not stored 377 * -# @c n-1 characters are stored, in which case failbit is set 378 * in the stream error state 379 * 380 * If no characters are extracted, failbit is set. (An empty line of 381 * input should therefore not cause failbit to be set.) 382 * 383 * In any case, a null character is stored in the next location in 384 * the array. 385 */ 386 __istream_type& 387 getline(char_type* __s, streamsize __n, char_type __delim); 388 389 /** 390 * @brief String extraction. 391 * @param s A character array in which to store the data. 392 * @param n Maximum number of characters to extract. 393 * @return *this 394 * 395 * Returns @c getline(s,n,widen('\n')). 396 */ 397 inline __istream_type& 398 getline(char_type* __s, streamsize __n) 399 { return this->getline(__s, __n, this->widen('\n')); } 400 401 /** 402 * @brief Discarding characters 403 * @param n Number of characters to discard. 404 * @param delim A "stop" character. 405 * @return *this 406 * 407 * Extracts characters and throws them away until one of the 408 * following happens: 409 * - if @a n @c != @c std::numeric_limits<int>::max(), @a n 410 * characters are extracted 411 * - the input sequence reaches end-of-file 412 * - the next character equals @a delim (in this case, the character 413 * is extracted); note that this condition will never occur if 414 * @a delim equals @c traits::eof(). 415 */ 416 __istream_type& 417 ignore(streamsize __n = 1, int_type __delim = traits_type::eof()); 418 419 /** 420 * @brief Looking ahead in the stream 421 * @return The next character, or eof(). 422 * 423 * If, after constructing the sentry object, @c good() is false, 424 * returns @c traits::eof(). Otherwise reads but does not extract 425 * the next input character. 426 */ 427 int_type 428 peek(); 429 430 /** 431 * @brief Extraction without delimiters. 432 * @param s A character array. 433 * @param n Maximum number of characters to store. 434 * @return *this 435 * 436 * If the stream state is @c good(), extracts characters and stores 437 * them into @a s until one of the following happens: 438 * - @a n characters are stored 439 * - the input sequence reaches end-of-file, in which case the error 440 * state is set to @c failbit|eofbit. 441 * 442 * @note This function is not overloaded on signed char and 443 * unsigned char. 444 */ 445 __istream_type& 446 read(char_type* __s, streamsize __n); 447 448 /** 449 * @brief Extraction until the buffer is exhausted, but no more. 450 * @param s A character array. 451 * @param n Maximum number of characters to store. 452 * @return The number of characters extracted. 453 * 454 * Extracts characters and stores them into @a s depending on the 455 * number of characters remaining in the streambuf's buffer, 456 * @c rdbuf()->in_avail(), called @c A here: 457 * - if @c A @c == @c -1, sets eofbit and extracts no characters 458 * - if @c A @c == @c 0, extracts no characters 459 * - if @c A @c > @c 0, extracts @c min(A,n) 460 * 461 * The goal is to empty the current buffer, and to not request any 462 * more from the external input sequence controlled by the streambuf. 463 */ 464 streamsize 465 readsome(char_type* __s, streamsize __n); 466 467 /** 468 * @brief Unextracting a single character. 469 * @param c The character to push back into the input stream. 470 * @return *this 471 * 472 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 473 * 474 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 475 * the error state. 476 * 477 * @note Since no characters are extracted, the next call to 478 * @c gcount() will return 0, as required by DR 60. 479 */ 480 __istream_type& 481 putback(char_type __c); 482 483 /** 484 * @brief Unextracting the previous character. 485 * @return *this 486 * 487 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 488 * 489 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 490 * the error state. 491 * 492 * @note Since no characters are extracted, the next call to 493 * @c gcount() will return 0, as required by DR 60. 494 */ 495 __istream_type& 496 unget(); 497 498 /** 499 * @brief Synchronizing the stream buffer. 500 * @return 0 on success, -1 on failure 501 * 502 * If @c rdbuf() is a null pointer, returns -1. 503 * 504 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 505 * sets badbit and returns -1. 506 * 507 * Otherwise, returns 0. 508 * 509 * @note This function does not count the number of characters 510 * extracted, if any, and therefore does not affect the next 511 * call to @c gcount(). 512 */ 513 int 514 sync(); 515 516 /** 517 * @brief Getting the current read position. 518 * @return A file position object. 519 * 520 * If @c fail() is not false, returns @c pos_type(-1) to indicate 521 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 522 * 523 * @note This function does not count the number of characters 524 * extracted, if any, and therefore does not affect the next 525 * call to @c gcount(). 526 */ 527 pos_type 528 tellg(); 529 530 /** 531 * @brief Changing the current read position. 532 * @param pos A file position object. 533 * @return *this 534 * 535 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 536 * that function fails, sets failbit. 537 * 538 * @note This function does not count the number of characters 539 * extracted, if any, and therefore does not affect the next 540 * call to @c gcount(). 541 */ 542 __istream_type& 543 seekg(pos_type); 544 545 /** 546 * @brief Changing the current read position. 547 * @param off A file offset object. 548 * @param dir The direction in which to seek. 549 * @return *this 550 * 551 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 552 * If that function fails, sets failbit. 553 * 554 * @note This function does not count the number of characters 555 * extracted, if any, and therefore does not affect the next 556 * call to @c gcount(). 557 */ 558 __istream_type& 559 seekg(off_type, ios_base::seekdir); 560 //@} 561 562 protected: 563 explicit 564 basic_istream(): _M_gcount(streamsize(0)) { } 565 }; 566 567 /** 568 * @brief Performs setup work for input streams. 569 * 570 * Objects of this class are created before all of the standard 571 * extractors are run. It is responsible for "exception-safe prefix and 572 * suffix operations," although only prefix actions are currently required 573 * by the standard. Additional actions may be added by the 574 * implementation, and we list them in 575 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 576 * under [27.6] notes. 577 */ 578 template<typename _CharT, typename _Traits> 579 class basic_istream<_CharT, _Traits>::sentry 580 { 581 public: 582 /// Easy access to dependant types. 583 typedef _Traits traits_type; 584 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 585 typedef basic_istream<_CharT, _Traits> __istream_type; 586 typedef typename __istream_type::__ctype_type __ctype_type; 587 typedef typename _Traits::int_type __int_type; 588 589 /** 590 * @brief The constructor performs all the work. 591 * @param is The input stream to guard. 592 * @param noskipws Whether to consume whitespace or not. 593 * 594 * If the stream state is good (@a is.good() is true), then the 595 * following actions are performed, otherwise the sentry state is 596 * false ("not okay") and failbit is set in the stream state. 597 * 598 * The sentry's preparatory actions are: 599 * 600 * -# if the stream is tied to an output stream, @c is.tie()->flush() 601 * is called to synchronize the output sequence 602 * -# if @a noskipws is false, and @c ios_base::skipws is set in 603 * @c is.flags(), the sentry extracts and discards whitespace 604 * characters from the stream. The currently imbued locale is 605 * used to determine whether each character is whitespace. 606 * 607 * If the stream state is still good, then the sentry state becomes 608 * true ("okay"). 609 */ 610 explicit 611 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 612 613 /** 614 * @brief Quick status checking. 615 * @return The sentry state. 616 * 617 * For ease of use, sentries may be converted to booleans. The 618 * return value is that of the sentry state (true == okay). 619 */ 620 operator bool() const { return _M_ok; } 621 622 private: 623 bool _M_ok; 624 }; 625 626 // [27.6.1.2.3] character extraction templates 627 //@{ 628 /** 629 * @brief Character extractors 630 * @param in An input stream. 631 * @param c A character reference. 632 * @return in 633 * 634 * Behaves like one of the formatted arithmetic extractors described in 635 * std::basic_istream. After constructing a sentry object with good 636 * status, this function extracts a character (if one is available) and 637 * stores it in @a c. Otherwise, sets failbit in the input stream. 638 */ 639 template<typename _CharT, typename _Traits> 640 basic_istream<_CharT, _Traits>& 641 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 642 643 template<class _Traits> 644 basic_istream<char, _Traits>& 645 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 646 { return (__in >> reinterpret_cast<char&>(__c)); } 647 648 template<class _Traits> 649 basic_istream<char, _Traits>& 650 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 651 { return (__in >> reinterpret_cast<char&>(__c)); } 652 //@} 653 654 //@{ 655 /** 656 * @brief Character string extractors 657 * @param in An input stream. 658 * @param s A pointer to a character array. 659 * @return in 660 * 661 * Behaves like one of the formatted arithmetic extractors described in 662 * std::basic_istream. After constructing a sentry object with good 663 * status, this function extracts up to @c n characters and stores them 664 * into the array starting at @a s. @c n is defined as: 665 * 666 * - if @c width() is greater than zero, @c n is width() 667 * - otherwise @c n is "the number of elements of the largest array of 668 * @c char_type that can store a terminating @c eos." [27.6.1.2.3]/6 669 * 670 * Characters are extracted and stored until one of the following happens: 671 * - @c n-1 characters are stored 672 * - EOF is reached 673 * - the next character is whitespace according to the current locale 674 * - the next character is a null byte (i.e., @c charT() ) 675 * 676 * @c width(0) is then called for the input stream. 677 * 678 * If no characters are extracted, sets failbit. 679 */ 680 template<typename _CharT, typename _Traits> 681 basic_istream<_CharT, _Traits>& 682 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 683 684 template<class _Traits> 685 basic_istream<char,_Traits>& 686 operator>>(basic_istream<char,_Traits>& __in, unsigned char* __s) 687 { return (__in >> reinterpret_cast<char*>(__s)); } 688 689 template<class _Traits> 690 basic_istream<char,_Traits>& 691 operator>>(basic_istream<char,_Traits>& __in, signed char* __s) 692 { return (__in >> reinterpret_cast<char*>(__s)); } 693 //@} 694 695 // 27.6.1.5 Template class basic_iostream 696 /** 697 * @brief Merging istream and ostream capabilities. 698 * 699 * This class multiply inherits from the input and output stream classes 700 * simply to provide a single interface. 701 */ 702 template<typename _CharT, typename _Traits> 703 class basic_iostream 704 : public basic_istream<_CharT, _Traits>, 705 public basic_ostream<_CharT, _Traits> 706 { 707 public: 708 // _GLIBCXX_RESOLVE_LIB_DEFECTS 709 // 271. basic_iostream missing typedefs 710 // Types (inherited): 711 typedef _CharT char_type; 712 typedef typename _Traits::int_type int_type; 713 typedef typename _Traits::pos_type pos_type; 714 typedef typename _Traits::off_type off_type; 715 typedef _Traits traits_type; 716 717 // Non-standard Types: 718 typedef basic_istream<_CharT, _Traits> __istream_type; 719 typedef basic_ostream<_CharT, _Traits> __ostream_type; 720 721 /** 722 * @brief Constructor does nothing. 723 * 724 * Both of the parent classes are initialized with the same 725 * streambuf pointer passed to this constructor. 726 */ 727 explicit 728 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 729 : __istream_type(), __ostream_type() 730 { this->init(__sb); } 731 732 /** 733 * @brief Destructor does nothing. 734 */ 735 virtual 736 ~basic_iostream() { } 737 738 protected: 739 explicit 740 basic_iostream() : __istream_type(), __ostream_type() 741 { } 742 }; 743 744 // [27.6.1.4] standard basic_istream manipulators 745 /** 746 * @brief Quick and easy way to eat whitespace 747 * 748 * This manipulator extracts whitespace characters, stopping when the 749 * next character is non-whitespace, or when the input sequence is empty. 750 * If the sequence is empty, @c eofbit is set in the stream, but not 751 * @c failbit. 752 * 753 * The current locale is used to distinguish whitespace characters. 754 * 755 * Example: 756 * @code 757 * MyClass mc; 758 * 759 * std::cin >> std::ws >> mc; 760 * @endcode 761 * will skip leading whitespace before calling operator>> on cin and your 762 * object. Note that the same effect can be achieved by creating a 763 * std::basic_istream::sentry inside your definition of operator>>. 764 */ 765 template<typename _CharT, typename _Traits> 766 basic_istream<_CharT, _Traits>& 767 ws(basic_istream<_CharT, _Traits>& __is); 768} // namespace std 769 770#ifndef _GLIBCXX_EXPORT_TEMPLATE 771# include <bits/istream.tcc> 772#endif 773 774#endif /* _GLIBCXX_ISTREAM */ 775