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 include/ostream
26 * This is a Standard C++ Library header.
27 */
28
29//
30// ISO C++ 14882: 27.6.2 Output streams
31//
32
33#ifndef _GLIBCXX_OSTREAM
34#define _GLIBCXX_OSTREAM 1
35
36#pragma GCC system_header
37
38#include <bits/requires_hosted.h> // iostreams
39
40#include <ios>
41#include <bits/ostream_insert.h>
42#if __cplusplus > 202002L
43# include <format>
44#endif
45
46# define __glibcxx_want_print
47#include <bits/version.h> // __glibcxx_syncbuf
48
49namespace 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:
77 typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
78 typedef basic_ios<_CharT, _Traits> __ios_type;
79 typedef basic_ostream<_CharT, _Traits> __ostream_type;
80 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
81 __num_put_type;
82 typedef ctype<_CharT> __ctype_type;
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
92 basic_ostream(__streambuf_type* __sb)
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
101 ~basic_ostream() { }
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 */
115 __ostream_type&
116 operator<<(__ostream_type& (*__pf)(__ostream_type&))
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
124 __ostream_type&
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
134 __ostream_type&
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 */
173 __ostream_type&
174 operator<<(long __n)
175 { return _M_insert(__n); }
176
177 __ostream_type&
178 operator<<(unsigned long __n)
179 { return _M_insert(__n); }
180
181 __ostream_type&
182 operator<<(bool __n)
183 { return _M_insert(__n); }
184
185 __ostream_type&
186 operator<<(short __n);
187
188 __ostream_type&
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
199 __ostream_type&
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"
210 __ostream_type&
211 operator<<(long long __n)
212 { return _M_insert(__n); }
213
214 __ostream_type&
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 */
230 __ostream_type&
231 operator<<(double __f)
232 { return _M_insert(__f); }
233
234 __ostream_type&
235 operator<<(float __f)
236 {
237 // _GLIBCXX_RESOLVE_LIB_DEFECTS
238 // 117. basic_ostream uses nonexistent num_put member functions.
239 return _M_insert(static_cast<double>(__f));
240 }
241
242 __ostream_type&
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(static_cast<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(static_cast<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(static_cast<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(static_cast<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(static_cast<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 */
300 __ostream_type&
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
457 basic_ostream&
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
481 /**
482 * @brief Performs setup work for output streams.
483 *
484 * Objects of this class are created before all of the standard
485 * inserters are run. It is responsible for <em>exception-safe prefix and
486 * suffix operations</em>.
487 */
488 template <typename _CharT, typename _Traits>
489 class basic_ostream<_CharT, _Traits>::sentry
490 {
491 // Data Members.
492 bool _M_ok;
493 basic_ostream<_CharT, _Traits>& _M_os;
494
495 public:
496 /**
497 * @brief The constructor performs preparatory work.
498 * @param __os The output stream to guard.
499 *
500 * If the stream state is good (@a __os.good() is true), then if the
501 * stream is tied to another output stream, @c is.tie()->flush()
502 * is called to synchronize the output sequences.
503 *
504 * If the stream state is still good, then the sentry state becomes
505 * true (@a okay).
506 */
507 explicit
508 sentry(basic_ostream<_CharT, _Traits>& __os);
509
510#pragma GCC diagnostic push
511#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
512 /**
513 * @brief Possibly flushes the stream.
514 *
515 * If @c ios_base::unitbuf is set in @c os.flags(), and
516 * @c std::uncaught_exception() is true, the sentry destructor calls
517 * @c flush() on the output stream.
518 */
519 ~sentry()
520 {
521 // XXX MT
522 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception())
523 {
524 // Can't call flush directly or else will get into recursive lock.
525 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
526 _M_os.setstate(ios_base::badbit);
527 }
528 }
529#pragma GCC diagnostic pop
530
531 /**
532 * @brief Quick status checking.
533 * @return The sentry state.
534 *
535 * For ease of use, sentries may be converted to booleans. The
536 * return value is that of the sentry state (true == okay).
537 */
538#if __cplusplus >= 201103L
539 explicit
540#endif
541 operator bool() const
542 { return _M_ok; }
543 };
544
545 ///@{
546 /**
547 * @brief Character inserters
548 * @param __out An output stream.
549 * @param __c A character.
550 * @return out
551 *
552 * Behaves like one of the formatted arithmetic inserters described in
553 * std::basic_ostream. After constructing a sentry object with good
554 * status, this function inserts a single character and any required
555 * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then
556 * called.
557 *
558 * If @p __c is of type @c char and the character type of the stream is not
559 * @c char, the character is widened before insertion.
560 */
561 template<typename _CharT, typename _Traits>
562 inline basic_ostream<_CharT, _Traits>&
563 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
564 {
565 if (__out.width() != 0)
566 return __ostream_insert(__out, &__c, 1);
567 __out.put(__c);
568 return __out;
569 }
570
571 template<typename _CharT, typename _Traits>
572 inline basic_ostream<_CharT, _Traits>&
573 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
574 { return (__out << __out.widen(__c)); }
575
576 // Specialization
577 template<typename _Traits>
578 inline basic_ostream<char, _Traits>&
579 operator<<(basic_ostream<char, _Traits>& __out, char __c)
580 {
581 if (__out.width() != 0)
582 return __ostream_insert(__out, &__c, 1);
583 __out.put(__c);
584 return __out;
585 }
586
587 // Signed and unsigned
588 template<typename _Traits>
589 inline basic_ostream<char, _Traits>&
590 operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
591 { return (__out << static_cast<char>(__c)); }
592
593 template<typename _Traits>
594 inline basic_ostream<char, _Traits>&
595 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
596 { return (__out << static_cast<char>(__c)); }
597
598#if __cplusplus > 201703L
599 // The following deleted overloads prevent formatting character values as
600 // numeric values.
601
602 template<typename _Traits>
603 basic_ostream<char, _Traits>&
604 operator<<(basic_ostream<char, _Traits>&, wchar_t) = delete;
605
606#ifdef _GLIBCXX_USE_CHAR8_T
607 template<typename _Traits>
608 basic_ostream<char, _Traits>&
609 operator<<(basic_ostream<char, _Traits>&, char8_t) = delete;
610#endif
611
612 template<typename _Traits>
613 basic_ostream<char, _Traits>&
614 operator<<(basic_ostream<char, _Traits>&, char16_t) = delete;
615
616 template<typename _Traits>
617 basic_ostream<char, _Traits>&
618 operator<<(basic_ostream<char, _Traits>&, char32_t) = delete;
619
620#ifdef _GLIBCXX_USE_WCHAR_T
621#ifdef _GLIBCXX_USE_CHAR8_T
622 template<typename _Traits>
623 basic_ostream<wchar_t, _Traits>&
624 operator<<(basic_ostream<wchar_t, _Traits>&, char8_t) = delete;
625#endif // _GLIBCXX_USE_CHAR8_T
626
627 template<typename _Traits>
628 basic_ostream<wchar_t, _Traits>&
629 operator<<(basic_ostream<wchar_t, _Traits>&, char16_t) = delete;
630
631 template<typename _Traits>
632 basic_ostream<wchar_t, _Traits>&
633 operator<<(basic_ostream<wchar_t, _Traits>&, char32_t) = delete;
634#endif // _GLIBCXX_USE_WCHAR_T
635#endif // C++20
636 ///@}
637
638 ///@{
639 /**
640 * @brief String inserters
641 * @param __out An output stream.
642 * @param __s A character string.
643 * @return out
644 * @pre @p __s must be a non-NULL pointer
645 *
646 * Behaves like one of the formatted arithmetic inserters described in
647 * std::basic_ostream. After constructing a sentry object with good
648 * status, this function inserts @c traits::length(__s) characters starting
649 * at @p __s, widened if necessary, followed by any required padding (as
650 * determined by [22.2.2.2.2]). @c __out.width(0) is then called.
651 */
652 template<typename _CharT, typename _Traits>
653 inline basic_ostream<_CharT, _Traits>&
654 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
655 {
656 if (!__s)
657 __out.setstate(ios_base::badbit);
658 else
659 __ostream_insert(__out, __s,
660 static_cast<streamsize>(_Traits::length(__s)));
661 return __out;
662 }
663
664 template<typename _CharT, typename _Traits>
665 basic_ostream<_CharT, _Traits> &
666 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
667
668 // Partial specializations
669 template<typename _Traits>
670 inline basic_ostream<char, _Traits>&
671 operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
672 {
673 if (!__s)
674 __out.setstate(ios_base::badbit);
675 else
676 __ostream_insert(__out, __s,
677 static_cast<streamsize>(_Traits::length(__s)));
678 return __out;
679 }
680
681 // Signed and unsigned
682 template<typename _Traits>
683 inline basic_ostream<char, _Traits>&
684 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
685 { return (__out << reinterpret_cast<const char*>(__s)); }
686
687 template<typename _Traits>
688 inline basic_ostream<char, _Traits> &
689 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
690 { return (__out << reinterpret_cast<const char*>(__s)); }
691
692#if __cplusplus > 201703L
693 // The following deleted overloads prevent formatting strings as
694 // pointer values.
695
696 template<typename _Traits>
697 basic_ostream<char, _Traits>&
698 operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete;
699
700#ifdef _GLIBCXX_USE_CHAR8_T
701 template<typename _Traits>
702 basic_ostream<char, _Traits>&
703 operator<<(basic_ostream<char, _Traits>&, const char8_t*) = delete;
704#endif // _GLIBCXX_USE_CHAR8_T
705
706 template<typename _Traits>
707 basic_ostream<char, _Traits>&
708 operator<<(basic_ostream<char, _Traits>&, const char16_t*) = delete;
709
710 template<typename _Traits>
711 basic_ostream<char, _Traits>&
712 operator<<(basic_ostream<char, _Traits>&, const char32_t*) = delete;
713
714#ifdef _GLIBCXX_USE_WCHAR_T
715#ifdef _GLIBCXX_USE_CHAR8_T
716 template<typename _Traits>
717 basic_ostream<wchar_t, _Traits>&
718 operator<<(basic_ostream<wchar_t, _Traits>&, const char8_t*) = delete;
719#endif
720
721 template<typename _Traits>
722 basic_ostream<wchar_t, _Traits>&
723 operator<<(basic_ostream<wchar_t, _Traits>&, const char16_t*) = delete;
724
725 template<typename _Traits>
726 basic_ostream<wchar_t, _Traits>&
727 operator<<(basic_ostream<wchar_t, _Traits>&, const char32_t*) = delete;
728#endif // _GLIBCXX_USE_WCHAR_T
729#endif // C++20
730 ///@}
731
732 // Standard basic_ostream manipulators
733
734 /**
735 * @brief Write a newline and flush the stream.
736 *
737 * This manipulator is often mistakenly used when a simple newline is
738 * desired, leading to poor buffering performance. See
739 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
740 * for more on this subject.
741 */
742 template<typename _CharT, typename _Traits>
743 inline basic_ostream<_CharT, _Traits>&
744 endl(basic_ostream<_CharT, _Traits>& __os)
745 { return flush(__os.put(__os.widen('\n'))); }
746
747 /**
748 * @brief Write a null character into the output sequence.
749 *
750 * <em>Null character</em> is @c CharT() by definition. For CharT
751 * of @c char, this correctly writes the ASCII @c NUL character
752 * string terminator.
753 */
754 template<typename _CharT, typename _Traits>
755 inline basic_ostream<_CharT, _Traits>&
756 ends(basic_ostream<_CharT, _Traits>& __os)
757 { return __os.put(_CharT()); }
758
759 /**
760 * @brief Flushes the output stream.
761 *
762 * This manipulator simply calls the stream's @c flush() member function.
763 */
764 template<typename _CharT, typename _Traits>
765 inline basic_ostream<_CharT, _Traits>&
766 flush(basic_ostream<_CharT, _Traits>& __os)
767 { return __os.flush(); }
768
769#if __cplusplus >= 201103L
770 // C++11 27.7.3.9 Rvalue stream insertion [ostream.rvalue]
771 // _GLIBCXX_RESOLVE_LIB_DEFECTS
772 // 1203. More useful rvalue stream insertion
773
774#if __cpp_concepts >= 201907L && __glibcxx_type_trait_variable_templates
775 // Use concepts if possible because they're cheaper to evaluate.
776 template<typename _Tp>
777 concept __derived_from_ios_base = is_class_v<_Tp>
778 && (!is_same_v<_Tp, ios_base>)
779 && requires (_Tp* __t, ios_base* __b) { __b = __t; };
780
781 template<typename _Os, typename _Tp>
782 requires __derived_from_ios_base<_Os>
783 && requires (_Os& __os, const _Tp& __t) { __os << __t; }
784 using __rvalue_stream_insertion_t = _Os&&;
785#else
786 template<typename _Tp>
787 using _Require_derived_from_ios_base
788 = _Require<is_class<_Tp>, __not_<is_same<_Tp, ios_base>>,
789 is_convertible<typename add_pointer<_Tp>::type, ios_base*>>;
790
791 template<typename _Os, typename _Tp,
792 typename = _Require_derived_from_ios_base<_Os>,
793 typename
794 = decltype(std::declval<_Os&>() << std::declval<const _Tp&>())>
795 using __rvalue_stream_insertion_t = _Os&&;
796#endif
797
798 /**
799 * @brief Generic inserter for rvalue stream
800 * @param __os An input stream.
801 * @param __x A reference to the object being inserted.
802 * @return __os
803 *
804 * This is just a forwarding function to allow insertion to
805 * rvalue streams since they won't bind to the inserter functions
806 * that take an lvalue reference.
807 */
808 template<typename _Ostream, typename _Tp>
809 inline __rvalue_stream_insertion_t<_Ostream, _Tp>
810 operator<<(_Ostream&& __os, const _Tp& __x)
811 {
812 __os << __x;
813 return std::move(__os);
814 }
815
816#ifdef __glibcxx_syncbuf // C++ >= 20 && HOSTED && CXX11ABI
817 template<typename _CharT, typename _Traits>
818 class __syncbuf_base : public basic_streambuf<_CharT, _Traits>
819 {
820 public:
821 static bool*
822 _S_get(basic_streambuf<_CharT, _Traits>* __buf [[maybe_unused]]) noexcept
823 {
824#if __cpp_rtti
825 if (auto __p = dynamic_cast<__syncbuf_base*>(__buf))
826 return &__p->_M_emit_on_sync;
827#endif
828 return nullptr;
829 }
830
831 protected:
832 __syncbuf_base(basic_streambuf<_CharT, _Traits>* __w = nullptr)
833 : _M_wrapped(__w)
834 { }
835
836 basic_streambuf<_CharT, _Traits>* _M_wrapped = nullptr;
837 bool _M_emit_on_sync = false;
838 bool _M_needs_sync = false;
839 };
840
841 template<typename _CharT, typename _Traits>
842 inline basic_ostream<_CharT, _Traits>&
843 emit_on_flush(basic_ostream<_CharT, _Traits>& __os)
844 {
845 if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
846 *__flag = true;
847 return __os;
848 }
849
850 template<typename _CharT, typename _Traits>
851 inline basic_ostream<_CharT, _Traits>&
852 noemit_on_flush(basic_ostream<_CharT, _Traits>& __os)
853 {
854 if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
855 *__flag = false;
856 return __os;
857 }
858
859 template<typename _CharT, typename _Traits>
860 inline basic_ostream<_CharT, _Traits>&
861 flush_emit(basic_ostream<_CharT, _Traits>& __os)
862 {
863 struct _Restore
864 {
865 ~_Restore() { *_M_flag = _M_prev; }
866
867 bool _M_prev = false;
868 bool* _M_flag = &_M_prev;
869 } __restore;
870
871 if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
872 {
873 __restore._M_prev = *__flag;
874 __restore._M_flag = __flag;
875 *__flag = true;
876 }
877
878 __os.flush();
879 return __os;
880 }
881#endif // __glibcxx_syncbuf
882
883#if __cpp_lib_print // C++ >= 23
884
885 inline void
886 vprint_nonunicode(ostream& __os, string_view __fmt, format_args __args)
887 {
888 ostream::sentry __cerb(__os);
889 if (__cerb)
890 {
891 __format::_Str_sink<char> __buf;
892 std::vformat_to(__buf.out(), __os.getloc(), __fmt, __args);
893 auto __out = __buf.view();
894
895 __try
896 {
897 std::__ostream_write(__os, __out.data(), __out.size());
898 }
899 __catch(const __cxxabiv1::__forced_unwind&)
900 {
901 __os._M_setstate(ios_base::badbit);
902 __throw_exception_again;
903 }
904 __catch(...)
905 { __os._M_setstate(ios_base::badbit); }
906 }
907 }
908
909 inline void
910 vprint_unicode(ostream& __os, string_view __fmt, format_args __args)
911 {
912#if !defined(_WIN32) || defined(__CYGWIN__)
913 // For most targets we don't need to do anything special to write
914 // Unicode to a terminal.
915 std::vprint_nonunicode(__os, __fmt, __args);
916#else
917 ostream::sentry __cerb(__os);
918 if (__cerb)
919 {
920 __format::_Str_sink<char> __buf;
921 std::vformat_to(__buf.out(), __os.getloc(), __fmt, __args);
922 auto __out = __buf.view();
923
924 void* __open_terminal(streambuf*);
925 error_code __write_to_terminal(void*, span<char>);
926 // If stream refers to a terminal, write a Unicode string to it.
927 if (auto __term = __open_terminal(__os.rdbuf()))
928 {
929#if !defined(_WIN32) || defined(__CYGWIN__)
930 // For POSIX, __open_terminal(streambuf*) uses fdopen to open a
931 // new file, so we would need to close it here. This code is not
932 // actually compiled because it's inside an #ifdef _WIN32 group,
933 // but just in case that changes in future ...
934 struct _Guard
935 {
936 _Guard(void* __p) : _M_f((FILE*)__p) { }
937 ~_Guard() { std::fclose(_M_f); }
938 _Guard(_Guard&&) = delete;
939 _Guard& operator=(_Guard&&) = delete;
940 FILE* _M_f;
941 };
942 _Guard __g(__term);
943#endif
944
945 ios_base::iostate __err = ios_base::goodbit;
946 __try
947 {
948 if (__os.rdbuf()->pubsync() == -1)
949 __err = ios::badbit;
950 else if (auto __e = __write_to_terminal(__term, __out))
951 if (__e != std::make_error_code(errc::illegal_byte_sequence))
952 __err = ios::badbit;
953 }
954 __catch(const __cxxabiv1::__forced_unwind&)
955 {
956 __os._M_setstate(ios_base::badbit);
957 __throw_exception_again;
958 }
959 __catch(...)
960 { __os._M_setstate(ios_base::badbit); }
961
962 if (__err)
963 __os.setstate(__err);
964 return;
965 }
966
967 // Otherwise just insert the string as vprint_nonunicode does.
968 __try
969 {
970 std::__ostream_write(__os, __out.data(), __out.size());
971 }
972 __catch(const __cxxabiv1::__forced_unwind&)
973 {
974 __os._M_setstate(ios_base::badbit);
975 __throw_exception_again;
976 }
977 __catch(...)
978 { __os._M_setstate(ios_base::badbit); }
979 }
980#endif // _WIN32
981 }
982
983 template<typename... _Args>
984 inline void
985 print(ostream& __os, format_string<_Args...> __fmt, _Args&&... __args)
986 {
987 auto __fmtargs = std::make_format_args(__args...);
988 if constexpr (__unicode::__literal_encoding_is_utf8())
989 std::vprint_unicode(__os, __fmt.get(), __fmtargs);
990 else
991 std::vprint_nonunicode(__os, __fmt.get(), __fmtargs);
992 }
993
994 template<typename... _Args>
995 inline void
996 println(ostream& __os, format_string<_Args...> __fmt, _Args&&... __args)
997 {
998 // _GLIBCXX_RESOLVE_LIB_DEFECTS
999 // 4088. println ignores the locale imbued in std::ostream
1000 std::print(__os, "{}\n", std::format(__os.getloc(), __fmt,
1001 std::forward<_Args>(__args)...));
1002 }
1003
1004 // Defined for C++26, supported as an extension to C++23.
1005 inline void println(ostream& __os)
1006 {
1007#if defined(_WIN32) && !defined(__CYGWIN__)
1008 if constexpr (__unicode::__literal_encoding_is_utf8())
1009 std::vprint_unicode(__os, "\n", std::make_format_args());
1010 else
1011#endif
1012 __os.put('\n');
1013 }
1014
1015#endif // __cpp_lib_print
1016
1017#endif // C++11
1018
1019_GLIBCXX_END_NAMESPACE_VERSION
1020} // namespace std
1021
1022#include <bits/ostream.tcc>
1023
1024#endif /* _GLIBCXX_OSTREAM */
1025