libstdc++
istream
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1 // Input streams -*- C++ -*-
2 
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
4 // 2006, 2007, 2008, 2009, 2010, 2011
5 // Free Software Foundation, Inc.
6 //
7 // This file is part of the GNU ISO C++ Library. This library is free
8 // software; you can redistribute it and/or modify it under the
9 // terms of the GNU General Public License as published by the
10 // Free Software Foundation; either version 3, or (at your option)
11 // any later version.
12 
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17 
18 // Under Section 7 of GPL version 3, you are granted additional
19 // permissions described in the GCC Runtime Library Exception, version
20 // 3.1, as published by the Free Software Foundation.
21 
22 // You should have received a copy of the GNU General Public License and
23 // a copy of the GCC Runtime Library Exception along with this program;
24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 // <http://www.gnu.org/licenses/>.
26 
27 //
28 // ISO C++ 14882: 27.6.1 Input streams
29 //
30 
31 /** @file include/istream
32  * This is a Standard C++ Library header.
33  */
34 
35 #ifndef _GLIBCXX_ISTREAM
36 #define _GLIBCXX_ISTREAM 1
37 
38 #pragma GCC system_header
39 
40 #include <ios>
41 #include <ostream>
42 
43 namespace std _GLIBCXX_VISIBILITY(default)
44 {
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
46 
47  // [27.6.1.1] Template class basic_istream
48  /**
49  * @brief Controlling input.
50  * @ingroup io
51  *
52  * This is the base class for all input streams. It provides text
53  * formatting of all builtin types, and communicates with any class
54  * derived from basic_streambuf to do the actual input.
55  */
56  template<typename _CharT, typename _Traits>
57  class basic_istream : virtual public basic_ios<_CharT, _Traits>
58  {
59  public:
60  // Types (inherited from basic_ios (27.4.4)):
61  typedef _CharT char_type;
62  typedef typename _Traits::int_type int_type;
63  typedef typename _Traits::pos_type pos_type;
64  typedef typename _Traits::off_type off_type;
65  typedef _Traits traits_type;
66 
67  // Non-standard Types:
68  typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
69  typedef basic_ios<_CharT, _Traits> __ios_type;
70  typedef basic_istream<_CharT, _Traits> __istream_type;
71  typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
72  __num_get_type;
73  typedef ctype<_CharT> __ctype_type;
74 
75  protected:
76  // Data Members:
77  /**
78  * The number of characters extracted in the previous unformatted
79  * function; see gcount().
80  */
82 
83  public:
84  // [27.6.1.1.1] constructor/destructor
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
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
104  { _M_gcount = streamsize(0); }
105 
106  // [27.6.1.1.2] prefix/suffix
107  class sentry;
108  friend class sentry;
109 
110  // [27.6.1.2] formatted input
111  // [27.6.1.2.3] basic_istream::operator>>
112  //@{
113  /**
114  * @brief Interface for manipulators.
115  *
116  * Manipulators such as @c std::ws and @c std::dec use these
117  * functions in constructs like
118  * <code>std::cin >> std::ws</code>.
119  * For more information, see the iomanip header.
120  */
121  __istream_type&
123  { return __pf(*this); }
124 
125  __istream_type&
127  {
128  __pf(*this);
129  return *this;
130  }
131 
132  __istream_type&
134  {
135  __pf(*this);
136  return *this;
137  }
138  //@}
139 
140  // [27.6.1.2.2] arithmetic extractors
141  /**
142  * @name Arithmetic Extractors
143  *
144  * All the @c operator>> functions (aka <em>formatted input
145  * functions</em>) have some common behavior. Each starts by
146  * constructing a temporary object of type std::basic_istream::sentry
147  * with the second argument (noskipws) set to false. This has several
148  * effects, concluding with the setting of a status flag; see the
149  * sentry documentation for more.
150  *
151  * If the sentry status is good, the function tries to extract
152  * whatever data is appropriate for the type of the argument.
153  *
154  * If an exception is thrown during extraction, ios_base::badbit
155  * will be turned on in the stream's error state without causing an
156  * ios_base::failure to be thrown. The original exception will then
157  * be rethrown.
158  */
159  //@{
160  /**
161  * @brief Basic arithmetic extractors
162  * @param A variable of builtin type.
163  * @return @c *this if successful
164  *
165  * These functions use the stream's current locale (specifically, the
166  * @c num_get facet) to parse the input data.
167  */
168  __istream_type&
169  operator>>(bool& __n)
170  { return _M_extract(__n); }
171 
172  __istream_type&
173  operator>>(short& __n);
174 
175  __istream_type&
176  operator>>(unsigned short& __n)
177  { return _M_extract(__n); }
178 
179  __istream_type&
180  operator>>(int& __n);
181 
182  __istream_type&
183  operator>>(unsigned int& __n)
184  { return _M_extract(__n); }
185 
186  __istream_type&
187  operator>>(long& __n)
188  { return _M_extract(__n); }
189 
190  __istream_type&
191  operator>>(unsigned long& __n)
192  { return _M_extract(__n); }
193 
194 #ifdef _GLIBCXX_USE_LONG_LONG
195  __istream_type&
196  operator>>(long long& __n)
197  { return _M_extract(__n); }
198 
199  __istream_type&
200  operator>>(unsigned long long& __n)
201  { return _M_extract(__n); }
202 #endif
203 
204  __istream_type&
205  operator>>(float& __f)
206  { return _M_extract(__f); }
207 
208  __istream_type&
209  operator>>(double& __f)
210  { return _M_extract(__f); }
211 
212  __istream_type&
213  operator>>(long double& __f)
214  { return _M_extract(__f); }
215 
216  __istream_type&
217  operator>>(void*& __p)
218  { return _M_extract(__p); }
219 
220  /**
221  * @brief Extracting into another streambuf.
222  * @param sb A pointer to a streambuf
223  *
224  * This function behaves like one of the basic arithmetic extractors,
225  * in that it also constructs a sentry object and has the same error
226  * handling behavior.
227  *
228  * If @a sb is NULL, the stream will set failbit in its error state.
229  *
230  * Characters are extracted from this stream and inserted into the
231  * @a sb streambuf until one of the following occurs:
232  *
233  * - the input stream reaches end-of-file,
234  * - insertion into the output buffer fails (in this case, the
235  * character that would have been inserted is not extracted), or
236  * - an exception occurs (and in this case is caught)
237  *
238  * If the function inserts no characters, failbit is set.
239  */
240  __istream_type&
241  operator>>(__streambuf_type* __sb);
242  //@}
243 
244  // [27.6.1.3] unformatted input
245  /**
246  * @brief Character counting
247  * @return The number of characters extracted by the previous
248  * unformatted input function dispatched for this stream.
249  */
250  streamsize
251  gcount() const
252  { return _M_gcount; }
253 
254  /**
255  * @name Unformatted Input Functions
256  *
257  * All the unformatted input functions have some common behavior.
258  * Each starts by constructing a temporary object of type
259  * std::basic_istream::sentry with the second argument (noskipws)
260  * set to true. This has several effects, concluding with the
261  * setting of a status flag; see the sentry documentation for more.
262  *
263  * If the sentry status is good, the function tries to extract
264  * whatever data is appropriate for the type of the argument.
265  *
266  * The number of characters extracted is stored for later retrieval
267  * by gcount().
268  *
269  * If an exception is thrown during extraction, ios_base::badbit
270  * will be turned on in the stream's error state without causing an
271  * ios_base::failure to be thrown. The original exception will then
272  * be rethrown.
273  */
274  //@{
275  /**
276  * @brief Simple extraction.
277  * @return A character, or eof().
278  *
279  * Tries to extract a character. If none are available, sets failbit
280  * and returns traits::eof().
281  */
282  int_type
283  get();
284 
285  /**
286  * @brief Simple extraction.
287  * @param c The character in which to store data.
288  * @return *this
289  *
290  * Tries to extract a character and store it in @a c. If none are
291  * available, sets failbit and returns traits::eof().
292  *
293  * @note This function is not overloaded on signed char and
294  * unsigned char.
295  */
296  __istream_type&
297  get(char_type& __c);
298 
299  /**
300  * @brief Simple multiple-character extraction.
301  * @param s Pointer to an array.
302  * @param n Maximum number of characters to store in @a s.
303  * @param delim A "stop" character.
304  * @return *this
305  *
306  * Characters are extracted and stored into @a s until one of the
307  * following happens:
308  *
309  * - @c n-1 characters are stored
310  * - the input sequence reaches EOF
311  * - the next character equals @a delim, in which case the character
312  * is not extracted
313  *
314  * If no characters are stored, failbit is set in the stream's error
315  * state.
316  *
317  * In any case, a null character is stored into the next location in
318  * the array.
319  *
320  * @note This function is not overloaded on signed char and
321  * unsigned char.
322  */
323  __istream_type&
324  get(char_type* __s, streamsize __n, char_type __delim);
325 
326  /**
327  * @brief Simple multiple-character extraction.
328  * @param s Pointer to an array.
329  * @param n Maximum number of characters to store in @a s.
330  * @return *this
331  *
332  * Returns @c get(s,n,widen(&apos;\\n&apos;)).
333  */
334  __istream_type&
335  get(char_type* __s, streamsize __n)
336  { return this->get(__s, __n, this->widen('\n')); }
337 
338  /**
339  * @brief Extraction into another streambuf.
340  * @param sb A streambuf in which to store data.
341  * @param delim A "stop" character.
342  * @return *this
343  *
344  * Characters are extracted and inserted into @a sb until one of the
345  * following happens:
346  *
347  * - the input sequence reaches EOF
348  * - insertion into the output buffer fails (in this case, the
349  * character that would have been inserted is not extracted)
350  * - the next character equals @a delim (in this case, the character
351  * is not extracted)
352  * - an exception occurs (and in this case is caught)
353  *
354  * If no characters are stored, failbit is set in the stream's error
355  * state.
356  */
357  __istream_type&
358  get(__streambuf_type& __sb, char_type __delim);
359 
360  /**
361  * @brief Extraction into another streambuf.
362  * @param sb A streambuf in which to store data.
363  * @return *this
364  *
365  * Returns @c get(sb,widen(&apos;\\n&apos;)).
366  */
367  __istream_type&
368  get(__streambuf_type& __sb)
369  { return this->get(__sb, this->widen('\n')); }
370 
371  /**
372  * @brief String extraction.
373  * @param s A character array in which to store the data.
374  * @param n Maximum number of characters to extract.
375  * @param delim A "stop" character.
376  * @return *this
377  *
378  * Extracts and stores characters into @a s until one of the
379  * following happens. Note that these criteria are required to be
380  * tested in the order listed here, to allow an input line to exactly
381  * fill the @a s array without setting failbit.
382  *
383  * -# the input sequence reaches end-of-file, in which case eofbit
384  * is set in the stream error state
385  * -# the next character equals @c delim, in which case the character
386  * is extracted (and therefore counted in @c gcount()) but not stored
387  * -# @c n-1 characters are stored, in which case failbit is set
388  * in the stream error state
389  *
390  * If no characters are extracted, failbit is set. (An empty line of
391  * input should therefore not cause failbit to be set.)
392  *
393  * In any case, a null character is stored in the next location in
394  * the array.
395  */
396  __istream_type&
397  getline(char_type* __s, streamsize __n, char_type __delim);
398 
399  /**
400  * @brief String extraction.
401  * @param s A character array in which to store the data.
402  * @param n Maximum number of characters to extract.
403  * @return *this
404  *
405  * Returns @c getline(s,n,widen(&apos;\\n&apos;)).
406  */
407  __istream_type&
409  { return this->getline(__s, __n, this->widen('\n')); }
410 
411  /**
412  * @brief Discarding characters
413  * @param n Number of characters to discard.
414  * @param delim A "stop" character.
415  * @return *this
416  *
417  * Extracts characters and throws them away until one of the
418  * following happens:
419  * - if @a n @c != @c std::numeric_limits<int>::max(), @a n
420  * characters are extracted
421  * - the input sequence reaches end-of-file
422  * - the next character equals @a delim (in this case, the character
423  * is extracted); note that this condition will never occur if
424  * @a delim equals @c traits::eof().
425  *
426  * NB: Provide three overloads, instead of the single function
427  * (with defaults) mandated by the Standard: this leads to a
428  * better performing implementation, while still conforming to
429  * the Standard.
430  */
431  __istream_type&
432  ignore();
433 
434  __istream_type&
435  ignore(streamsize __n);
436 
437  __istream_type&
438  ignore(streamsize __n, int_type __delim);
439 
440  /**
441  * @brief Looking ahead in the stream
442  * @return The next character, or eof().
443  *
444  * If, after constructing the sentry object, @c good() is false,
445  * returns @c traits::eof(). Otherwise reads but does not extract
446  * the next input character.
447  */
448  int_type
449  peek();
450 
451  /**
452  * @brief Extraction without delimiters.
453  * @param s A character array.
454  * @param n Maximum number of characters to store.
455  * @return *this
456  *
457  * If the stream state is @c good(), extracts characters and stores
458  * them into @a s until one of the following happens:
459  * - @a n characters are stored
460  * - the input sequence reaches end-of-file, in which case the error
461  * state is set to @c failbit|eofbit.
462  *
463  * @note This function is not overloaded on signed char and
464  * unsigned char.
465  */
466  __istream_type&
467  read(char_type* __s, streamsize __n);
468 
469  /**
470  * @brief Extraction until the buffer is exhausted, but no more.
471  * @param s A character array.
472  * @param n Maximum number of characters to store.
473  * @return The number of characters extracted.
474  *
475  * Extracts characters and stores them into @a s depending on the
476  * number of characters remaining in the streambuf's buffer,
477  * @c rdbuf()->in_avail(), called @c A here:
478  * - if @c A @c == @c -1, sets eofbit and extracts no characters
479  * - if @c A @c == @c 0, extracts no characters
480  * - if @c A @c > @c 0, extracts @c min(A,n)
481  *
482  * The goal is to empty the current buffer, and to not request any
483  * more from the external input sequence controlled by the streambuf.
484  */
485  streamsize
486  readsome(char_type* __s, streamsize __n);
487 
488  /**
489  * @brief Unextracting a single character.
490  * @param c The character to push back into the input stream.
491  * @return *this
492  *
493  * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c).
494  *
495  * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in
496  * the error state.
497  *
498  * @note This function first clears eofbit. Since no characters
499  * are extracted, the next call to @c gcount() will return 0,
500  * as required by DR 60.
501  */
502  __istream_type&
503  putback(char_type __c);
504 
505  /**
506  * @brief Unextracting the previous character.
507  * @return *this
508  *
509  * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c).
510  *
511  * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in
512  * the error state.
513  *
514  * @note This function first clears eofbit. Since no characters
515  * are extracted, the next call to @c gcount() will return 0,
516  * as required by DR 60.
517  */
518  __istream_type&
519  unget();
520 
521  /**
522  * @brief Synchronizing the stream buffer.
523  * @return 0 on success, -1 on failure
524  *
525  * If @c rdbuf() is a null pointer, returns -1.
526  *
527  * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
528  * sets badbit and returns -1.
529  *
530  * Otherwise, returns 0.
531  *
532  * @note This function does not count the number of characters
533  * extracted, if any, and therefore does not affect the next
534  * call to @c gcount().
535  */
536  int
537  sync();
538 
539  /**
540  * @brief Getting the current read position.
541  * @return A file position object.
542  *
543  * If @c fail() is not false, returns @c pos_type(-1) to indicate
544  * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in).
545  *
546  * @note This function does not count the number of characters
547  * extracted, if any, and therefore does not affect the next
548  * call to @c gcount(). At variance with putback, unget and
549  * seekg, eofbit is not cleared first.
550  */
551  pos_type
552  tellg();
553 
554  /**
555  * @brief Changing the current read position.
556  * @param pos A file position object.
557  * @return *this
558  *
559  * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
560  * that function fails, sets failbit.
561  *
562  * @note This function first clears eofbit. It does not count the
563  * number of characters extracted, if any, and therefore does
564  * not affect the next call to @c gcount().
565  */
566  __istream_type&
567  seekg(pos_type);
568 
569  /**
570  * @brief Changing the current read position.
571  * @param off A file offset object.
572  * @param dir The direction in which to seek.
573  * @return *this
574  *
575  * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
576  * If that function fails, sets failbit.
577  *
578  * @note This function first clears eofbit. It does not count the
579  * number of characters extracted, if any, and therefore does
580  * not affect the next call to @c gcount().
581  */
582  __istream_type&
583  seekg(off_type, ios_base::seekdir);
584  //@}
585 
586  protected:
587  basic_istream()
588  : _M_gcount(streamsize(0))
589  { this->init(0); }
590 
591  template<typename _ValueT>
592  __istream_type&
593  _M_extract(_ValueT& __v);
594  };
595 
596  // Explicit specialization declarations, defined in src/istream.cc.
597  template<>
598  basic_istream<char>&
600  getline(char_type* __s, streamsize __n, char_type __delim);
601 
602  template<>
603  basic_istream<char>&
605  ignore(streamsize __n);
606 
607  template<>
608  basic_istream<char>&
610  ignore(streamsize __n, int_type __delim);
611 
612 #ifdef _GLIBCXX_USE_WCHAR_T
613  template<>
614  basic_istream<wchar_t>&
616  getline(char_type* __s, streamsize __n, char_type __delim);
617 
618  template<>
619  basic_istream<wchar_t>&
621  ignore(streamsize __n);
622 
623  template<>
624  basic_istream<wchar_t>&
626  ignore(streamsize __n, int_type __delim);
627 #endif
628 
629  /**
630  * @brief Performs setup work for input streams.
631  *
632  * Objects of this class are created before all of the standard
633  * extractors are run. It is responsible for <em>exception-safe
634  * prefix and suffix operations,</em> although only prefix actions
635  * are currently required by the standard.
636  */
637  template<typename _CharT, typename _Traits>
638  class basic_istream<_CharT, _Traits>::sentry
639  {
640  // Data Members.
641  bool _M_ok;
642 
643  public:
644  /// Easy access to dependant types.
645  typedef _Traits traits_type;
649  typedef typename _Traits::int_type __int_type;
650 
651  /**
652  * @brief The constructor performs all the work.
653  * @param is The input stream to guard.
654  * @param noskipws Whether to consume whitespace or not.
655  *
656  * If the stream state is good (@a is.good() is true), then the
657  * following actions are performed, otherwise the sentry state
658  * is false (<em>not okay</em>) and failbit is set in the
659  * stream state.
660  *
661  * The sentry's preparatory actions are:
662  *
663  * -# if the stream is tied to an output stream, @c is.tie()->flush()
664  * is called to synchronize the output sequence
665  * -# if @a noskipws is false, and @c ios_base::skipws is set in
666  * @c is.flags(), the sentry extracts and discards whitespace
667  * characters from the stream. The currently imbued locale is
668  * used to determine whether each character is whitespace.
669  *
670  * If the stream state is still good, then the sentry state becomes
671  * true (@a okay).
672  */
673  explicit
674  sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false);
675 
676  /**
677  * @brief Quick status checking.
678  * @return The sentry state.
679  *
680  * For ease of use, sentries may be converted to booleans. The
681  * return value is that of the sentry state (true == okay).
682  */
683 #ifdef __GXX_EXPERIMENTAL_CXX0X__
684  explicit
685 #endif
686  operator bool() const
687  { return _M_ok; }
688  };
689 
690  // [27.6.1.2.3] character extraction templates
691  //@{
692  /**
693  * @brief Character extractors
694  * @param in An input stream.
695  * @param c A character reference.
696  * @return in
697  *
698  * Behaves like one of the formatted arithmetic extractors described in
699  * std::basic_istream. After constructing a sentry object with good
700  * status, this function extracts a character (if one is available) and
701  * stores it in @a c. Otherwise, sets failbit in the input stream.
702  */
703  template<typename _CharT, typename _Traits>
705  operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c);
706 
707  template<class _Traits>
709  operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
710  { return (__in >> reinterpret_cast<char&>(__c)); }
711 
712  template<class _Traits>
713  inline basic_istream<char, _Traits>&
714  operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
715  { return (__in >> reinterpret_cast<char&>(__c)); }
716  //@}
717 
718  //@{
719  /**
720  * @brief Character string extractors
721  * @param in An input stream.
722  * @param s A pointer to a character array.
723  * @return in
724  *
725  * Behaves like one of the formatted arithmetic extractors described in
726  * std::basic_istream. After constructing a sentry object with good
727  * status, this function extracts up to @c n characters and stores them
728  * into the array starting at @a s. @c n is defined as:
729  *
730  * - if @c width() is greater than zero, @c n is width() otherwise
731  * - @c n is <em>the number of elements of the largest array of *
732  * - @c char_type that can store a terminating @c eos.</em>
733  * - [27.6.1.2.3]/6
734  *
735  * Characters are extracted and stored until one of the following happens:
736  * - @c n-1 characters are stored
737  * - EOF is reached
738  * - the next character is whitespace according to the current locale
739  * - the next character is a null byte (i.e., @c charT() )
740  *
741  * @c width(0) is then called for the input stream.
742  *
743  * If no characters are extracted, sets failbit.
744  */
745  template<typename _CharT, typename _Traits>
746  basic_istream<_CharT, _Traits>&
747  operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s);
748 
749  // Explicit specialization declaration, defined in src/istream.cc.
750  template<>
751  basic_istream<char>&
752  operator>>(basic_istream<char>& __in, char* __s);
753 
754  template<class _Traits>
755  inline basic_istream<char, _Traits>&
756  operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
757  { return (__in >> reinterpret_cast<char*>(__s)); }
758 
759  template<class _Traits>
760  inline basic_istream<char, _Traits>&
761  operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
762  { return (__in >> reinterpret_cast<char*>(__s)); }
763  //@}
764 
765  // 27.6.1.5 Template class basic_iostream
766  /**
767  * @brief Merging istream and ostream capabilities.
768  * @ingroup io
769  *
770  * This class multiply inherits from the input and output stream classes
771  * simply to provide a single interface.
772  */
773  template<typename _CharT, typename _Traits>
774  class basic_iostream
775  : public basic_istream<_CharT, _Traits>,
776  public basic_ostream<_CharT, _Traits>
777  {
778  public:
779  // _GLIBCXX_RESOLVE_LIB_DEFECTS
780  // 271. basic_iostream missing typedefs
781  // Types (inherited):
782  typedef _CharT char_type;
783  typedef typename _Traits::int_type int_type;
784  typedef typename _Traits::pos_type pos_type;
785  typedef typename _Traits::off_type off_type;
786  typedef _Traits traits_type;
787 
788  // Non-standard Types:
789  typedef basic_istream<_CharT, _Traits> __istream_type;
790  typedef basic_ostream<_CharT, _Traits> __ostream_type;
791 
792  /**
793  * @brief Constructor does nothing.
794  *
795  * Both of the parent classes are initialized with the same
796  * streambuf pointer passed to this constructor.
797  */
798  explicit
800  : __istream_type(__sb), __ostream_type(__sb) { }
801 
802  /**
803  * @brief Destructor does nothing.
804  */
805  virtual
807 
808  protected:
810  : __istream_type(), __ostream_type() { }
811  };
812 
813  // [27.6.1.4] standard basic_istream manipulators
814  /**
815  * @brief Quick and easy way to eat whitespace
816  *
817  * This manipulator extracts whitespace characters, stopping when the
818  * next character is non-whitespace, or when the input sequence is empty.
819  * If the sequence is empty, @c eofbit is set in the stream, but not
820  * @c failbit.
821  *
822  * The current locale is used to distinguish whitespace characters.
823  *
824  * Example:
825  * @code
826  * MyClass mc;
827  *
828  * std::cin >> std::ws >> mc;
829  * @endcode
830  * will skip leading whitespace before calling operator>> on cin and your
831  * object. Note that the same effect can be achieved by creating a
832  * std::basic_istream::sentry inside your definition of operator>>.
833  */
834  template<typename _CharT, typename _Traits>
835  basic_istream<_CharT, _Traits>&
836  ws(basic_istream<_CharT, _Traits>& __is);
837 
838 #ifdef __GXX_EXPERIMENTAL_CXX0X__
839  // [27.7.1.6] Rvalue stream extraction
840  /**
841  * @brief Generic extractor for rvalue stream
842  * @param is An input stream.
843  * @param x A reference to the extraction target.
844  * @return is
845  *
846  * This is just a forwarding function to allow extraction from
847  * rvalue streams since they won't bind to the extractor functions
848  * that take an lvalue reference.
849  */
850  template<typename _CharT, typename _Traits, typename _Tp>
851  inline basic_istream<_CharT, _Traits>&
853  { return (__is >> __x); }
854 #endif // __GXX_EXPERIMENTAL_CXX0X__
855 
856 _GLIBCXX_END_NAMESPACE_VERSION
857 } // namespace
858 
859 #include <bits/istream.tcc>
860 
861 #endif /* _GLIBCXX_ISTREAM */
The base of the I/O class hierarchy.This class defines everything that can be defined about I/O that ...
Definition: ios_base.h:201
__istream_type & operator>>(unsigned int &__n)
Basic arithmetic extractors.
Definition: istream:183
virtual ~basic_iostream()
Destructor does nothing.
Definition: istream:806
basic_iostream(basic_streambuf< _CharT, _Traits > *__sb)
Constructor does nothing.
Definition: istream:799
__istream_type & operator>>(void *&__p)
Basic arithmetic extractors.
Definition: istream:217
streamsize _M_gcount
Definition: istream:81
_Traits traits_type
Easy access to dependant types.
Definition: istream:645
__istream_type & operator>>(__ios_type &(*__pf)(__ios_type &))
Interface for manipulators.
Definition: istream:126
__istream_type & operator>>(unsigned short &__n)
Basic arithmetic extractors.
Definition: istream:176
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition: postypes.h:100
__istream_type & operator>>(double &__f)
Basic arithmetic extractors.
Definition: istream:209
int sync()
Synchronizing the stream buffer.
Definition: istream.tcc:783
__istream_type & getline(char_type *__s, streamsize __n, char_type __delim)
String extraction.
Definition: istream.tcc:402
Primary class template ctype facet.This template class defines classification and conversion function...
__istream_type & operator>>(unsigned long &__n)
Basic arithmetic extractors.
Definition: istream:191
__istream_type & getline(char_type *__s, streamsize __n)
String extraction.
Definition: istream:408
bitset< _Nb > operator>>(size_t __position) const
Self-explanatory.
Definition: bitset:1336
__istream_type & operator>>(long &__n)
Basic arithmetic extractors.
Definition: istream:187
streamsize gcount() const
Character counting.
Definition: istream:251
__istream_type & ignore()
Discarding characters.
Definition: istream.tcc:462
__istream_type & unget()
Unextracting the previous character.
Definition: istream.tcc:748
pos_type tellg()
Getting the current read position.
Definition: istream.tcc:819
basic_istream< _CharT, _Traits > & ws(basic_istream< _CharT, _Traits > &__is)
Quick and easy way to eat whitespace.
Definition: istream.tcc:1018
__istream_type & operator>>(float &__f)
Basic arithmetic extractors.
Definition: istream:205
__istream_type & operator>>(ios_base &(*__pf)(ios_base &))
Interface for manipulators.
Definition: istream:133
Merging istream and ostream capabilities.This class multiply inherits from the input and output strea...
Definition: iosfwd:91
streamsize readsome(char_type *__s, streamsize __n)
Extraction until the buffer is exhausted, but no more.
Definition: istream.tcc:681
int_type peek()
Looking ahead in the stream.
Definition: istream.tcc:622
__istream_type & operator>>(long double &__f)
Basic arithmetic extractors.
Definition: istream:213
__istream_type & operator>>(bool &__n)
Basic arithmetic extractors.
Definition: istream:169
void init(basic_streambuf< _CharT, _Traits > *__sb)
All setup is performed here.
Definition: basic_ios.tcc:127
__istream_type & operator>>(long long &__n)
Basic arithmetic extractors.
Definition: istream:196
__istream_type & putback(char_type __c)
Unextracting a single character.
Definition: istream.tcc:713
Performs setup work for input streams.
Definition: istream:638
virtual ~basic_istream()
Base destructor.
Definition: istream:103
__istream_type & operator>>(__istream_type &(*__pf)(__istream_type &))
Interface for manipulators.
Definition: istream:122
char_type widen(char __c) const
Widens characters.
Definition: basic_ios.h:441
__istream_type & seekg(pos_type)
Changing the current read position.
Definition: istream.tcc:847
basic_istream(__streambuf_type *__sb)
Base constructor.
Definition: istream:93
__istream_type & read(char_type *__s, streamsize __n)
Extraction without delimiters.
Definition: istream.tcc:652
__istream_type & operator>>(unsigned long long &__n)
Basic arithmetic extractors.
Definition: istream:200