libstdc++
ostream.h
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1 // Output streams -*- C++ -*-
2 
3 // Copyright (C) 1997-2024 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/ostream.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{ostream}
28  */
29 
30 //
31 // ISO C++ 14882: 27.6.2 Output streams
32 //
33 
34 #ifndef _GLIBCXX_OSTREAM_H
35 #define _GLIBCXX_OSTREAM_H 1
36 
37 #ifdef _GLIBCXX_SYSHDR
38 #pragma GCC system_header
39 #endif
40 
41 #include <bits/requires_hosted.h> // iostreams
42 
43 #include <ios>
44 #include <bits/ostream_insert.h>
45 
46 # define __glibcxx_want_print
47 #include <bits/version.h> // __glibcxx_syncbuf
48 
49 namespace std _GLIBCXX_VISIBILITY(default)
50 {
51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
52 
53  /**
54  * @brief Template class basic_ostream.
55  * @ingroup io
56  *
57  * @tparam _CharT Type of character stream.
58  * @tparam _Traits Traits for character type, defaults to
59  * char_traits<_CharT>.
60  *
61  * This is the base class for all output streams. It provides text
62  * formatting of all builtin types, and communicates with any class
63  * derived from basic_streambuf to do the actual output.
64  */
65  template<typename _CharT, typename _Traits>
66  class basic_ostream : virtual public basic_ios<_CharT, _Traits>
67  {
68  public:
69  // Types (inherited from basic_ios):
70  typedef _CharT char_type;
71  typedef typename _Traits::int_type int_type;
72  typedef typename _Traits::pos_type pos_type;
73  typedef typename _Traits::off_type off_type;
74  typedef _Traits traits_type;
75 
76  // Non-standard Types:
83 
84  /**
85  * @brief Base constructor.
86  *
87  * This ctor is almost never called by the user directly, rather from
88  * derived classes' initialization lists, which pass a pointer to
89  * their own stream buffer.
90  */
91  explicit
93  { this->init(__sb); }
94 
95  /**
96  * @brief Base destructor.
97  *
98  * This does very little apart from providing a virtual base dtor.
99  */
100  virtual
102 
103  /// Safe prefix/suffix operations.
104  class sentry;
105  friend class sentry;
106 
107  ///@{
108  /**
109  * @brief Interface for manipulators.
110  *
111  * Manipulators such as @c std::endl and @c std::hex use these
112  * functions in constructs like "std::cout << std::endl". For more
113  * information, see the iomanip header.
114  */
117  {
118  // _GLIBCXX_RESOLVE_LIB_DEFECTS
119  // DR 60. What is a formatted input function?
120  // The inserters for manipulators are *not* formatted output functions.
121  return __pf(*this);
122  }
123 
125  operator<<(__ios_type& (*__pf)(__ios_type&))
126  {
127  // _GLIBCXX_RESOLVE_LIB_DEFECTS
128  // DR 60. What is a formatted input function?
129  // The inserters for manipulators are *not* formatted output functions.
130  __pf(*this);
131  return *this;
132  }
133 
135  operator<<(ios_base& (*__pf) (ios_base&))
136  {
137  // _GLIBCXX_RESOLVE_LIB_DEFECTS
138  // DR 60. What is a formatted input function?
139  // The inserters for manipulators are *not* formatted output functions.
140  __pf(*this);
141  return *this;
142  }
143  ///@}
144 
145  ///@{
146  /**
147  * @name Inserters
148  *
149  * All the @c operator<< functions (aka <em>formatted output
150  * functions</em>) have some common behavior. Each starts by
151  * constructing a temporary object of type std::basic_ostream::sentry.
152  * This can have several effects, concluding with the setting of a
153  * status flag; see the sentry documentation for more.
154  *
155  * If the sentry status is good, the function tries to generate
156  * whatever data is appropriate for the type of the argument.
157  *
158  * If an exception is thrown during insertion, ios_base::badbit
159  * will be turned on in the stream's error state without causing an
160  * ios_base::failure to be thrown. The original exception will then
161  * be rethrown.
162  */
163 
164  ///@{
165  /**
166  * @brief Integer arithmetic inserters
167  * @param __n A variable of builtin integral type.
168  * @return @c *this if successful
169  *
170  * These functions use the stream's current locale (specifically, the
171  * @c num_get facet) to perform numeric formatting.
172  */
174  operator<<(long __n)
175  { return _M_insert(__n); }
176 
178  operator<<(unsigned long __n)
179  { return _M_insert(__n); }
180 
182  operator<<(bool __n)
183  { return _M_insert(__n); }
184 
185  __ostream_type&
186  operator<<(short __n);
187 
189  operator<<(unsigned short __n)
190  {
191  // _GLIBCXX_RESOLVE_LIB_DEFECTS
192  // 117. basic_ostream uses nonexistent num_put member functions.
193  return _M_insert(static_cast<unsigned long>(__n));
194  }
195 
196  __ostream_type&
197  operator<<(int __n);
198 
200  operator<<(unsigned int __n)
201  {
202  // _GLIBCXX_RESOLVE_LIB_DEFECTS
203  // 117. basic_ostream uses nonexistent num_put member functions.
204  return _M_insert(static_cast<unsigned long>(__n));
205  }
206 
207 #ifdef _GLIBCXX_USE_LONG_LONG
208 #pragma GCC diagnostic push
209 #pragma GCC diagnostic ignored "-Wlong-long"
211  operator<<(long long __n)
212  { return _M_insert(__n); }
213 
215  operator<<(unsigned long long __n)
216  { return _M_insert(__n); }
217 #pragma GCC diagnostic pop
218 #endif
219  ///@}
220 
221  ///@{
222  /**
223  * @brief Floating point arithmetic inserters
224  * @param __f A variable of builtin floating point type.
225  * @return @c *this if successful
226  *
227  * These functions use the stream's current locale (specifically, the
228  * @c num_get facet) to perform numeric formatting.
229  */
231  operator<<(double __f)
232  { return _M_insert(__f); }
233 
235  operator<<(float __f)
236  {
237  // _GLIBCXX_RESOLVE_LIB_DEFECTS
238  // 117. basic_ostream uses nonexistent num_put member functions.
239  return _M_insert(_S_cast_flt<double>(__f));
240  }
241 
243  operator<<(long double __f)
244  { return _M_insert(__f); }
245  ///@}
246 
247 #if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
248  __attribute__((__always_inline__))
249  __ostream_type&
250  operator<<(_Float16 __f)
251  {
252  return _M_insert(_S_cast_flt<double>(__f));
253  }
254 #endif
255 
256 #if defined(__STDCPP_FLOAT32_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
257  __attribute__((__always_inline__))
258  __ostream_type&
259  operator<<(_Float32 __f)
260  {
261  return _M_insert(_S_cast_flt<double>(__f));
262  }
263 #endif
264 
265 #if defined(__STDCPP_FLOAT64_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
266  __attribute__((__always_inline__))
267  __ostream_type&
268  operator<<(_Float64 __f)
269  {
270  return _M_insert(_S_cast_flt<double>(__f));
271  }
272 #endif
273 
274 #if defined(__STDCPP_FLOAT128_T__) && defined(_GLIBCXX_LDOUBLE_IS_IEEE_BINARY128)
275  __attribute__((__always_inline__))
276  __ostream_type&
277  operator<<(_Float128 __f)
278  {
279  return _M_insert(_S_cast_flt<long double>(__f));
280  }
281 #endif
282 
283 #if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
284  __attribute__((__always_inline__))
285  __ostream_type&
286  operator<<(__gnu_cxx::__bfloat16_t __f)
287  {
288  return _M_insert(_S_cast_flt<double>(__f));
289  }
290 #endif
291 
292  /**
293  * @brief Pointer arithmetic inserters
294  * @param __p A variable of pointer type.
295  * @return @c *this if successful
296  *
297  * These functions use the stream's current locale (specifically, the
298  * @c num_get facet) to perform numeric formatting.
299  */
301  operator<<(const void* __p)
302  { return _M_insert(__p); }
303 
304 #if __cplusplus >= 201703L
305  __ostream_type&
306  operator<<(nullptr_t)
307  { return *this << "nullptr"; }
308 #endif
309 
310 #if __cplusplus > 202002L
311  __attribute__((__always_inline__))
312  __ostream_type&
313  operator<<(const volatile void* __p)
314  { return _M_insert(const_cast<const void*>(__p)); }
315 #endif
316 
317  /**
318  * @brief Extracting from another streambuf.
319  * @param __sb A pointer to a streambuf
320  *
321  * This function behaves like one of the basic arithmetic extractors,
322  * in that it also constructs a sentry object and has the same error
323  * handling behavior.
324  *
325  * If @p __sb is NULL, the stream will set failbit in its error state.
326  *
327  * Characters are extracted from @p __sb and inserted into @c *this
328  * until one of the following occurs:
329  *
330  * - the input stream reaches end-of-file,
331  * - insertion into the output sequence fails (in this case, the
332  * character that would have been inserted is not extracted), or
333  * - an exception occurs while getting a character from @p __sb, which
334  * sets failbit in the error state
335  *
336  * If the function inserts no characters, failbit is set.
337  */
338  __ostream_type&
339  operator<<(__streambuf_type* __sb);
340  ///@}
341 
342  ///@{
343  /**
344  * @name Unformatted Output Functions
345  *
346  * All the unformatted output functions have some common behavior.
347  * Each starts by constructing a temporary object of type
348  * std::basic_ostream::sentry. This has several effects, concluding
349  * with the setting of a status flag; see the sentry documentation
350  * for more.
351  *
352  * If the sentry status is good, the function tries to generate
353  * whatever data is appropriate for the type of the argument.
354  *
355  * If an exception is thrown during insertion, ios_base::badbit
356  * will be turned on in the stream's error state. If badbit is on in
357  * the stream's exceptions mask, the exception will be rethrown
358  * without completing its actions.
359  */
360 
361  /**
362  * @brief Simple insertion.
363  * @param __c The character to insert.
364  * @return *this
365  *
366  * Tries to insert @p __c.
367  *
368  * @note This function is not overloaded on signed char and
369  * unsigned char.
370  */
371  __ostream_type&
372  put(char_type __c);
373 
374  /**
375  * @brief Character string insertion.
376  * @param __s The array to insert.
377  * @param __n Maximum number of characters to insert.
378  * @return *this
379  *
380  * Characters are copied from @p __s and inserted into the stream until
381  * one of the following happens:
382  *
383  * - @p __n characters are inserted
384  * - inserting into the output sequence fails (in this case, badbit
385  * will be set in the stream's error state)
386  *
387  * @note This function is not overloaded on signed char and
388  * unsigned char.
389  */
390  __ostream_type&
391  write(const char_type* __s, streamsize __n);
392  ///@}
393 
394  /**
395  * @brief Synchronizing the stream buffer.
396  * @return *this
397  *
398  * If @c rdbuf() is a null pointer, changes nothing.
399  *
400  * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
401  * sets badbit.
402  */
403  __ostream_type&
404  flush();
405 
406  /**
407  * @brief Getting the current write position.
408  * @return A file position object.
409  *
410  * If @c fail() is not false, returns @c pos_type(-1) to indicate
411  * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
412  */
413  pos_type
414  tellp();
415 
416  /**
417  * @brief Changing the current write position.
418  * @param __pos A file position object.
419  * @return *this
420  *
421  * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
422  * that function fails, sets failbit.
423  */
424  __ostream_type&
425  seekp(pos_type);
426 
427  /**
428  * @brief Changing the current write position.
429  * @param __off A file offset object.
430  * @param __dir The direction in which to seek.
431  * @return *this
432  *
433  * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
434  * If that function fails, sets failbit.
435  */
436  __ostream_type&
437  seekp(off_type, ios_base::seekdir);
438 
439  protected:
440  basic_ostream()
441  { this->init(0); }
442 
443 #if __cplusplus >= 201103L
444  // Non-standard constructor that does not call init()
445  basic_ostream(basic_iostream<_CharT, _Traits>&) { }
446 
447  basic_ostream(const basic_ostream&) = delete;
448 
449  basic_ostream(basic_ostream&& __rhs)
450  : __ios_type()
451  { __ios_type::move(__rhs); }
452 
453  // 27.7.3.3 Assign/swap
454 
455  basic_ostream& operator=(const basic_ostream&) = delete;
456 
458  operator=(basic_ostream&& __rhs)
459  {
460  swap(__rhs);
461  return *this;
462  }
463 
464  void
465  swap(basic_ostream& __rhs)
466  { __ios_type::swap(__rhs); }
467 #endif
468 
469  template<typename _ValueT>
470  __ostream_type&
471  _M_insert(_ValueT __v);
472 
473  private:
474 #if !_GLIBCXX_INLINE_VERSION
475  void
476  _M_write(const char_type* __s, streamsize __n)
477  { std::__ostream_insert(*this, __s, __n); }
478 #endif
479 
480 #pragma GCC diagnostic push
481 #pragma GCC diagnostic ignored "-Wc++17-extensions" // for if-constexpr
482  template<typename _To, typename _From>
483  static _To
484  _S_cast_flt(_From __f)
485  {
486  _To __d = static_cast<_To>(__f);
487  // _GLIBCXX_RESOLVE_LIB_DEFECTS
488  // 4101: LWG 117 loses the sign for negative NaN on some arches.
489 #if defined __riscv
490  _To __sign;
491 #if __cpp_constexpr && __has_builtin(__builtin_bit_cast)
492  if constexpr (sizeof(__f) == sizeof(short))
493  __sign = static_cast<_To>(__builtin_bit_cast(short, __f));
494  else if constexpr (sizeof(__f) == sizeof(int))
495  __sign = static_cast<_To>(__builtin_bit_cast(int, __f));
496  else if constexpr (sizeof(__f) == sizeof(long long))
497  __sign = static_cast<_To>(__builtin_bit_cast(long long, __f));
498  else
499 #endif
500  __sign = __builtin_signbit(__f) ? _To(-1.0) : _To(+1.0);
501 
502  if _GLIBCXX17_CONSTEXPR (__is_same(_To, double))
503  __d = __builtin_copysign(__d, __sign);
504  else if _GLIBCXX17_CONSTEXPR (__is_same(_To, long double))
505  __d = __builtin_copysignl(__d, __sign);
506 #endif
507  return __d;
508  }
509 #pragma GCC diagnostic pop
510 
511  // RAII type to clear and restore an ostream's exceptions mask.
512  struct _Disable_exceptions
513  {
514  _Disable_exceptions(basic_ostream& __os)
515  : _M_os(__os), _M_exception(_M_os._M_exception)
516  { _M_os._M_exception = ios_base::goodbit; }
517 
518  ~_Disable_exceptions()
519  { _M_os._M_exception = _M_exception; }
520 
521 #pragma GCC diagnostic push
522 #pragma GCC diagnostic ignored "-Wc++11-extensions" // deleted functions
523  _Disable_exceptions(const _Disable_exceptions&) = delete;
524  _Disable_exceptions& operator=(const _Disable_exceptions&) = delete;
525 #pragma GCC diagnostic pop
526 
527  private:
528  basic_ostream& _M_os;
529  const ios_base::iostate _M_exception;
530  };
531  };
532 
533  /**
534  * @brief Performs setup work for output streams.
535  *
536  * Objects of this class are created before all of the standard
537  * inserters are run. It is responsible for <em>exception-safe prefix and
538  * suffix operations</em>.
539  */
540  template <typename _CharT, typename _Traits>
541  class basic_ostream<_CharT, _Traits>::sentry
542  {
543  // Data Members.
544  bool _M_ok;
546 
547  public:
548  /**
549  * @brief The constructor performs preparatory work.
550  * @param __os The output stream to guard.
551  *
552  * If the stream state is good (@a __os.good() is true), then if the
553  * stream is tied to another output stream, @c is.tie()->flush()
554  * is called to synchronize the output sequences.
555  *
556  * If the stream state is still good, then the sentry state becomes
557  * true (@a okay).
558  */
559  explicit
561 
562 #pragma GCC diagnostic push
563 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
564  /**
565  * @brief Possibly flushes the stream.
566  *
567  * If `ios_base::unitbuf` is set in `os.flags()`, and
568  * `std::uncaught_exception()` is true, the sentry destructor flushes
569  * the output stream.
570  */
572  {
573  // _GLIBCXX_RESOLVE_LIB_DEFECTS
574  // 397. ostream::sentry dtor throws exceptions
575  // 835. Tying two streams together (correction to DR 581)
576  // 4188. ostream::sentry destructor should handle exceptions
577  if (bool(_M_os.flags() & ios_base::unitbuf) && _M_os.good()
578  && !uncaught_exception()) // XXX MT
579  {
580  _Disable_exceptions __noex(_M_os);
581  __try
582  {
583  // Can't call _M_os.flush() directly because that constructs
584  // another sentry.
585  if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
586  _M_os.setstate(ios_base::badbit);
587  }
588  __catch(...)
589  { _M_os.setstate(ios_base::badbit); }
590  }
591  }
592 #pragma GCC diagnostic pop
593 
594  /**
595  * @brief Quick status checking.
596  * @return The sentry state.
597  *
598  * For ease of use, sentries may be converted to booleans. The
599  * return value is that of the sentry state (true == okay).
600  */
601 #if __cplusplus >= 201103L
602  explicit
603 #endif
604  operator bool() const
605  { return _M_ok; }
606  };
607 
608  ///@{
609  /**
610  * @brief Character inserters
611  * @param __out An output stream.
612  * @param __c A character.
613  * @return out
614  *
615  * Behaves like one of the formatted arithmetic inserters described in
616  * std::basic_ostream. After constructing a sentry object with good
617  * status, this function inserts a single character and any required
618  * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then
619  * called.
620  *
621  * If @p __c is of type @c char and the character type of the stream is not
622  * @c char, the character is widened before insertion.
623  */
624  template<typename _CharT, typename _Traits>
626  operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
627  {
628  if (__out.width() != 0)
629  return __ostream_insert(__out, &__c, 1);
630  __out.put(__c);
631  return __out;
632  }
633 
634  template<typename _CharT, typename _Traits>
635  inline basic_ostream<_CharT, _Traits>&
636  operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
637  { return (__out << __out.widen(__c)); }
638 
639  // Specialization
640  template<typename _Traits>
641  inline basic_ostream<char, _Traits>&
642  operator<<(basic_ostream<char, _Traits>& __out, char __c)
643  {
644  if (__out.width() != 0)
645  return __ostream_insert(__out, &__c, 1);
646  __out.put(__c);
647  return __out;
648  }
649 
650  // Signed and unsigned
651  template<typename _Traits>
652  inline basic_ostream<char, _Traits>&
653  operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
654  { return (__out << static_cast<char>(__c)); }
655 
656  template<typename _Traits>
657  inline basic_ostream<char, _Traits>&
658  operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
659  { return (__out << static_cast<char>(__c)); }
660 
661 #if __cplusplus > 201703L
662  // The following deleted overloads prevent formatting character values as
663  // numeric values.
664 
665  template<typename _Traits>
666  basic_ostream<char, _Traits>&
667  operator<<(basic_ostream<char, _Traits>&, wchar_t) = delete;
668 
669 #ifdef _GLIBCXX_USE_CHAR8_T
670  template<typename _Traits>
671  basic_ostream<char, _Traits>&
672  operator<<(basic_ostream<char, _Traits>&, char8_t) = delete;
673 #endif
674 
675  template<typename _Traits>
676  basic_ostream<char, _Traits>&
677  operator<<(basic_ostream<char, _Traits>&, char16_t) = delete;
678 
679  template<typename _Traits>
680  basic_ostream<char, _Traits>&
681  operator<<(basic_ostream<char, _Traits>&, char32_t) = delete;
682 
683 #ifdef _GLIBCXX_USE_WCHAR_T
684 #ifdef _GLIBCXX_USE_CHAR8_T
685  template<typename _Traits>
686  basic_ostream<wchar_t, _Traits>&
687  operator<<(basic_ostream<wchar_t, _Traits>&, char8_t) = delete;
688 #endif // _GLIBCXX_USE_CHAR8_T
689 
690  template<typename _Traits>
691  basic_ostream<wchar_t, _Traits>&
692  operator<<(basic_ostream<wchar_t, _Traits>&, char16_t) = delete;
693 
694  template<typename _Traits>
695  basic_ostream<wchar_t, _Traits>&
696  operator<<(basic_ostream<wchar_t, _Traits>&, char32_t) = delete;
697 #endif // _GLIBCXX_USE_WCHAR_T
698 #endif // C++20
699  ///@}
700 
701  ///@{
702  /**
703  * @brief String inserters
704  * @param __out An output stream.
705  * @param __s A character string.
706  * @return out
707  * @pre @p __s must be a non-NULL pointer
708  *
709  * Behaves like one of the formatted arithmetic inserters described in
710  * std::basic_ostream. After constructing a sentry object with good
711  * status, this function inserts @c traits::length(__s) characters starting
712  * at @p __s, widened if necessary, followed by any required padding (as
713  * determined by [22.2.2.2.2]). @c __out.width(0) is then called.
714  */
715  template<typename _CharT, typename _Traits>
716  inline basic_ostream<_CharT, _Traits>&
717  operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
718  {
719  if (!__s)
720  __out.setstate(ios_base::badbit);
721  else
722  __ostream_insert(__out, __s,
723  static_cast<streamsize>(_Traits::length(__s)));
724  return __out;
725  }
726 
727  template<typename _CharT, typename _Traits>
728  basic_ostream<_CharT, _Traits> &
729  operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
730 
731  // Partial specializations
732  template<typename _Traits>
733  inline basic_ostream<char, _Traits>&
734  operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
735  {
736  if (!__s)
737  __out.setstate(ios_base::badbit);
738  else
739  __ostream_insert(__out, __s,
740  static_cast<streamsize>(_Traits::length(__s)));
741  return __out;
742  }
743 
744  // Signed and unsigned
745  template<typename _Traits>
746  inline basic_ostream<char, _Traits>&
747  operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
748  { return (__out << reinterpret_cast<const char*>(__s)); }
749 
750  template<typename _Traits>
751  inline basic_ostream<char, _Traits> &
752  operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
753  { return (__out << reinterpret_cast<const char*>(__s)); }
754 
755 #if __cplusplus > 201703L
756  // The following deleted overloads prevent formatting strings as
757  // pointer values.
758 
759  template<typename _Traits>
760  basic_ostream<char, _Traits>&
761  operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete;
762 
763 #ifdef _GLIBCXX_USE_CHAR8_T
764  template<typename _Traits>
765  basic_ostream<char, _Traits>&
766  operator<<(basic_ostream<char, _Traits>&, const char8_t*) = delete;
767 #endif // _GLIBCXX_USE_CHAR8_T
768 
769  template<typename _Traits>
770  basic_ostream<char, _Traits>&
771  operator<<(basic_ostream<char, _Traits>&, const char16_t*) = delete;
772 
773  template<typename _Traits>
774  basic_ostream<char, _Traits>&
775  operator<<(basic_ostream<char, _Traits>&, const char32_t*) = delete;
776 
777 #ifdef _GLIBCXX_USE_WCHAR_T
778 #ifdef _GLIBCXX_USE_CHAR8_T
779  template<typename _Traits>
780  basic_ostream<wchar_t, _Traits>&
781  operator<<(basic_ostream<wchar_t, _Traits>&, const char8_t*) = delete;
782 #endif
783 
784  template<typename _Traits>
785  basic_ostream<wchar_t, _Traits>&
786  operator<<(basic_ostream<wchar_t, _Traits>&, const char16_t*) = delete;
787 
788  template<typename _Traits>
789  basic_ostream<wchar_t, _Traits>&
790  operator<<(basic_ostream<wchar_t, _Traits>&, const char32_t*) = delete;
791 #endif // _GLIBCXX_USE_WCHAR_T
792 #endif // C++20
793  ///@}
794 
795 #if __cplusplus >= 201103L
796  // C++11 27.7.3.9 Rvalue stream insertion [ostream.rvalue]
797  // _GLIBCXX_RESOLVE_LIB_DEFECTS
798  // 1203. More useful rvalue stream insertion
799 
800 #if __cpp_concepts >= 201907L && __glibcxx_type_trait_variable_templates
801  // Use concepts if possible because they're cheaper to evaluate.
802  template<typename _Tp>
803  concept __derived_from_ios_base = is_class_v<_Tp>
804  && (!is_same_v<_Tp, ios_base>)
805  && requires (_Tp* __t, ios_base* __b) { __b = __t; };
806 
807  template<typename _Os, typename _Tp>
808  requires __derived_from_ios_base<_Os>
809  && requires (_Os& __os, const _Tp& __t) { __os << __t; }
810  using __rvalue_stream_insertion_t = _Os&&;
811 #else
812  template<typename _Tp>
813  using _Require_derived_from_ios_base
814  = _Require<is_class<_Tp>, __not_<is_same<_Tp, ios_base>>,
815  is_convertible<typename add_pointer<_Tp>::type, ios_base*>>;
816 
817  template<typename _Os, typename _Tp,
818  typename = _Require_derived_from_ios_base<_Os>,
819  typename
820  = decltype(std::declval<_Os&>() << std::declval<const _Tp&>())>
821  using __rvalue_stream_insertion_t = _Os&&;
822 #endif
823 
824  /**
825  * @brief Generic inserter for rvalue stream
826  * @param __os An input stream.
827  * @param __x A reference to the object being inserted.
828  * @return __os
829  *
830  * This is just a forwarding function to allow insertion to
831  * rvalue streams since they won't bind to the inserter functions
832  * that take an lvalue reference.
833  */
834  template<typename _Ostream, typename _Tp>
835  inline __rvalue_stream_insertion_t<_Ostream, _Tp>
836  operator<<(_Ostream&& __os, const _Tp& __x)
837  {
838  __os << __x;
839  return std::move(__os);
840  }
841 #endif // C++11
842 
843 _GLIBCXX_END_NAMESPACE_VERSION
844 } // namespace std
845 
846 #endif /* _GLIBCXX_OSTREAM_H */
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:138
bool uncaught_exception() noexcept
ISO C++ entities toplevel namespace is std.
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition: postypes.h:73
std::basic_ostream< _CharT, _Traits > & operator<<(std::basic_ostream< _CharT, _Traits > &__os, const bitset< _Nb > &__x)
Global I/O operators for bitsets.
Definition: bitset:1692
Template class basic_ios, virtual base class for all stream classes.
Definition: basic_ios.h:70
_Traits::pos_type pos_type
Definition: basic_ios.h:84
basic_streambuf< _CharT, _Traits > * rdbuf() const
Accessing the underlying buffer.
Definition: basic_ios.h:337
_Traits traits_type
Definition: basic_ios.h:86
void setstate(iostate __state)
Sets additional flags in the error state.
Definition: basic_ios.h:166
void init(basic_streambuf< _CharT, _Traits > *__sb)
All setup is performed here.
Definition: basic_ios.tcc:131
bool good() const
Fast error checking.
Definition: basic_ios.h:190
_Traits::off_type off_type
Definition: basic_ios.h:85
_CharT char_type
Definition: basic_ios.h:72
_Traits::int_type int_type
Definition: basic_ios.h:83
The actual work of input and output (interface).
Definition: streambuf:127
Template class basic_ostream.
Definition: ostream.h:67
__ostream_type & write(const char_type *__s, streamsize __n)
Character string insertion.
Definition: ostream.tcc:192
__ostream_type & operator<<(__ostream_type &(*__pf)(__ostream_type &))
Interface for manipulators.
Definition: ostream.h:116
pos_type tellp()
Getting the current write position.
Definition: ostream.tcc:261
__ostream_type & put(char_type __c)
Simple insertion.
Definition: ostream.tcc:158
basic_ostream(__streambuf_type *__sb)
Base constructor.
Definition: ostream.h:92
__ostream_type & flush()
Synchronizing the stream buffer.
Definition: ostream.tcc:226
__ostream_type & seekp(pos_type)
Changing the current write position.
Definition: ostream.tcc:273
virtual ~basic_ostream()
Base destructor.
Definition: ostream.h:101
The base of the I/O class hierarchy.
Definition: ios_base.h:266
_Ios_Iostate iostate
This is a bitmask type.
Definition: ios_base.h:453
fmtflags flags() const
Access to format flags.
Definition: ios_base.h:694
static const iostate goodbit
Indicates all is well.
Definition: ios_base.h:468
static const fmtflags unitbuf
Flushes output after each output operation.
Definition: ios_base.h:426
static const iostate badbit
Indicates a loss of integrity in an input or output sequence (such as an irrecoverable read error fro...
Definition: ios_base.h:457
streamsize width() const
Flags access.
Definition: ios_base.h:789
_Ios_Seekdir seekdir
This is an enumerated type.
Definition: ios_base.h:523
Primary class template ctype facet.
Primary class template num_put.
Performs setup work for output streams.
Definition: ostream.h:542
~sentry()
Possibly flushes the stream.
Definition: ostream.h:571