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 __ostream_type&
209 operator<<(long long __n)
210 { return _M_insert(__n); }
211
212 __ostream_type&
213 operator<<(unsigned long long __n)
214 { return _M_insert(__n); }
215#endif
216 ///@}
217
218 ///@{
219 /**
220 * @brief Floating point arithmetic inserters
221 * @param __f A variable of builtin floating point type.
222 * @return @c *this if successful
223 *
224 * These functions use the stream's current locale (specifically, the
225 * @c num_get facet) to perform numeric formatting.
226 */
227 __ostream_type&
228 operator<<(double __f)
229 { return _M_insert(__f); }
230
231 __ostream_type&
232 operator<<(float __f)
233 {
234 // _GLIBCXX_RESOLVE_LIB_DEFECTS
235 // 117. basic_ostream uses nonexistent num_put member functions.
236 return _M_insert(static_cast<double>(__f));
237 }
238
239 __ostream_type&
240 operator<<(long double __f)
241 { return _M_insert(__f); }
242 ///@}
243
244#if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
245 __attribute__((__always_inline__))
246 __ostream_type&
247 operator<<(_Float16 __f)
248 {
249 return _M_insert(static_cast<double>(__f));
250 }
251#endif
252
253#if defined(__STDCPP_FLOAT32_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
254 __attribute__((__always_inline__))
255 __ostream_type&
256 operator<<(_Float32 __f)
257 {
258 return _M_insert(static_cast<double>(__f));
259 }
260#endif
261
262#if defined(__STDCPP_FLOAT64_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
263 __attribute__((__always_inline__))
264 __ostream_type&
265 operator<<(_Float64 __f)
266 {
267 return _M_insert(static_cast<double>(__f));
268 }
269#endif
270
271#if defined(__STDCPP_FLOAT128_T__) && defined(_GLIBCXX_LDOUBLE_IS_IEEE_BINARY128)
272 __attribute__((__always_inline__))
273 __ostream_type&
274 operator<<(_Float128 __f)
275 {
276 return _M_insert(static_cast<long double>(__f));
277 }
278#endif
279
280#if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
281 __attribute__((__always_inline__))
282 __ostream_type&
283 operator<<(__gnu_cxx::__bfloat16_t __f)
284 {
285 return _M_insert(static_cast<double>(__f));
286 }
287#endif
288
289 /**
290 * @brief Pointer arithmetic inserters
291 * @param __p A variable of pointer type.
292 * @return @c *this if successful
293 *
294 * These functions use the stream's current locale (specifically, the
295 * @c num_get facet) to perform numeric formatting.
296 */
297 __ostream_type&
298 operator<<(const void* __p)
299 { return _M_insert(__p); }
300
301#if __cplusplus >= 201703L
302 __ostream_type&
303 operator<<(nullptr_t)
304 { return *this << "nullptr"; }
305#endif
306
307#if __cplusplus > 202002L
308 __attribute__((__always_inline__))
309 __ostream_type&
310 operator<<(const volatile void* __p)
311 { return _M_insert(const_cast<const void*>(__p)); }
312#endif
313
314 /**
315 * @brief Extracting from another streambuf.
316 * @param __sb A pointer to a streambuf
317 *
318 * This function behaves like one of the basic arithmetic extractors,
319 * in that it also constructs a sentry object and has the same error
320 * handling behavior.
321 *
322 * If @p __sb is NULL, the stream will set failbit in its error state.
323 *
324 * Characters are extracted from @p __sb and inserted into @c *this
325 * until one of the following occurs:
326 *
327 * - the input stream reaches end-of-file,
328 * - insertion into the output sequence fails (in this case, the
329 * character that would have been inserted is not extracted), or
330 * - an exception occurs while getting a character from @p __sb, which
331 * sets failbit in the error state
332 *
333 * If the function inserts no characters, failbit is set.
334 */
335 __ostream_type&
336 operator<<(__streambuf_type* __sb);
337 ///@}
338
339 ///@{
340 /**
341 * @name Unformatted Output Functions
342 *
343 * All the unformatted output functions have some common behavior.
344 * Each starts by constructing a temporary object of type
345 * std::basic_ostream::sentry. This has several effects, concluding
346 * with the setting of a status flag; see the sentry documentation
347 * for more.
348 *
349 * If the sentry status is good, the function tries to generate
350 * whatever data is appropriate for the type of the argument.
351 *
352 * If an exception is thrown during insertion, ios_base::badbit
353 * will be turned on in the stream's error state. If badbit is on in
354 * the stream's exceptions mask, the exception will be rethrown
355 * without completing its actions.
356 */
357
358 /**
359 * @brief Simple insertion.
360 * @param __c The character to insert.
361 * @return *this
362 *
363 * Tries to insert @p __c.
364 *
365 * @note This function is not overloaded on signed char and
366 * unsigned char.
367 */
368 __ostream_type&
369 put(char_type __c);
370
371 /**
372 * @brief Character string insertion.
373 * @param __s The array to insert.
374 * @param __n Maximum number of characters to insert.
375 * @return *this
376 *
377 * Characters are copied from @p __s and inserted into the stream until
378 * one of the following happens:
379 *
380 * - @p __n characters are inserted
381 * - inserting into the output sequence fails (in this case, badbit
382 * will be set in the stream's error state)
383 *
384 * @note This function is not overloaded on signed char and
385 * unsigned char.
386 */
387 __ostream_type&
388 write(const char_type* __s, streamsize __n);
389 ///@}
390
391 /**
392 * @brief Synchronizing the stream buffer.
393 * @return *this
394 *
395 * If @c rdbuf() is a null pointer, changes nothing.
396 *
397 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
398 * sets badbit.
399 */
400 __ostream_type&
401 flush();
402
403 /**
404 * @brief Getting the current write position.
405 * @return A file position object.
406 *
407 * If @c fail() is not false, returns @c pos_type(-1) to indicate
408 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
409 */
410 pos_type
411 tellp();
412
413 /**
414 * @brief Changing the current write position.
415 * @param __pos A file position object.
416 * @return *this
417 *
418 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
419 * that function fails, sets failbit.
420 */
421 __ostream_type&
422 seekp(pos_type);
423
424 /**
425 * @brief Changing the current write position.
426 * @param __off A file offset object.
427 * @param __dir The direction in which to seek.
428 * @return *this
429 *
430 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
431 * If that function fails, sets failbit.
432 */
433 __ostream_type&
434 seekp(off_type, ios_base::seekdir);
435
436 protected:
437 basic_ostream()
438 { this->init(0); }
439
440#if __cplusplus >= 201103L
441 // Non-standard constructor that does not call init()
442 basic_ostream(basic_iostream<_CharT, _Traits>&) { }
443
444 basic_ostream(const basic_ostream&) = delete;
445
446 basic_ostream(basic_ostream&& __rhs)
447 : __ios_type()
448 { __ios_type::move(__rhs); }
449
450 // 27.7.3.3 Assign/swap
451
452 basic_ostream& operator=(const basic_ostream&) = delete;
453
454 basic_ostream&
455 operator=(basic_ostream&& __rhs)
456 {
457 swap(__rhs);
458 return *this;
459 }
460
461 void
462 swap(basic_ostream& __rhs)
463 { __ios_type::swap(__rhs); }
464#endif
465
466 template<typename _ValueT>
467 __ostream_type&
468 _M_insert(_ValueT __v);
469
470 private:
471#if !_GLIBCXX_INLINE_VERSION
472 void
473 _M_write(const char_type* __s, streamsize __n)
474 { std::__ostream_insert(*this, __s, __n); }
475#endif
476 };
477
478 /**
479 * @brief Performs setup work for output streams.
480 *
481 * Objects of this class are created before all of the standard
482 * inserters are run. It is responsible for <em>exception-safe prefix and
483 * suffix operations</em>.
484 */
485 template <typename _CharT, typename _Traits>
486 class basic_ostream<_CharT, _Traits>::sentry
487 {
488 // Data Members.
489 bool _M_ok;
490 basic_ostream<_CharT, _Traits>& _M_os;
491
492 public:
493 /**
494 * @brief The constructor performs preparatory work.
495 * @param __os The output stream to guard.
496 *
497 * If the stream state is good (@a __os.good() is true), then if the
498 * stream is tied to another output stream, @c is.tie()->flush()
499 * is called to synchronize the output sequences.
500 *
501 * If the stream state is still good, then the sentry state becomes
502 * true (@a okay).
503 */
504 explicit
505 sentry(basic_ostream<_CharT, _Traits>& __os);
506
507#pragma GCC diagnostic push
508#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
509 /**
510 * @brief Possibly flushes the stream.
511 *
512 * If @c ios_base::unitbuf is set in @c os.flags(), and
513 * @c std::uncaught_exception() is true, the sentry destructor calls
514 * @c flush() on the output stream.
515 */
516 ~sentry()
517 {
518 // XXX MT
519 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception())
520 {
521 // Can't call flush directly or else will get into recursive lock.
522 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
523 _M_os.setstate(ios_base::badbit);
524 }
525 }
526#pragma GCC diagnostic pop
527
528 /**
529 * @brief Quick status checking.
530 * @return The sentry state.
531 *
532 * For ease of use, sentries may be converted to booleans. The
533 * return value is that of the sentry state (true == okay).
534 */
535#if __cplusplus >= 201103L
536 explicit
537#endif
538 operator bool() const
539 { return _M_ok; }
540 };
541
542 ///@{
543 /**
544 * @brief Character inserters
545 * @param __out An output stream.
546 * @param __c A character.
547 * @return out
548 *
549 * Behaves like one of the formatted arithmetic inserters described in
550 * std::basic_ostream. After constructing a sentry object with good
551 * status, this function inserts a single character and any required
552 * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then
553 * called.
554 *
555 * If @p __c is of type @c char and the character type of the stream is not
556 * @c char, the character is widened before insertion.
557 */
558 template<typename _CharT, typename _Traits>
559 inline basic_ostream<_CharT, _Traits>&
560 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
561 {
562 if (__out.width() != 0)
563 return __ostream_insert(__out, &__c, 1);
564 __out.put(__c);
565 return __out;
566 }
567
568 template<typename _CharT, typename _Traits>
569 inline basic_ostream<_CharT, _Traits>&
570 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
571 { return (__out << __out.widen(__c)); }
572
573 // Specialization
574 template<typename _Traits>
575 inline basic_ostream<char, _Traits>&
576 operator<<(basic_ostream<char, _Traits>& __out, char __c)
577 {
578 if (__out.width() != 0)
579 return __ostream_insert(__out, &__c, 1);
580 __out.put(__c);
581 return __out;
582 }
583
584 // Signed and unsigned
585 template<typename _Traits>
586 inline basic_ostream<char, _Traits>&
587 operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
588 { return (__out << static_cast<char>(__c)); }
589
590 template<typename _Traits>
591 inline basic_ostream<char, _Traits>&
592 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
593 { return (__out << static_cast<char>(__c)); }
594
595#if __cplusplus > 201703L
596 // The following deleted overloads prevent formatting character values as
597 // numeric values.
598
599 template<typename _Traits>
600 basic_ostream<char, _Traits>&
601 operator<<(basic_ostream<char, _Traits>&, wchar_t) = delete;
602
603#ifdef _GLIBCXX_USE_CHAR8_T
604 template<typename _Traits>
605 basic_ostream<char, _Traits>&
606 operator<<(basic_ostream<char, _Traits>&, char8_t) = delete;
607#endif
608
609 template<typename _Traits>
610 basic_ostream<char, _Traits>&
611 operator<<(basic_ostream<char, _Traits>&, char16_t) = delete;
612
613 template<typename _Traits>
614 basic_ostream<char, _Traits>&
615 operator<<(basic_ostream<char, _Traits>&, char32_t) = delete;
616
617#ifdef _GLIBCXX_USE_WCHAR_T
618#ifdef _GLIBCXX_USE_CHAR8_T
619 template<typename _Traits>
620 basic_ostream<wchar_t, _Traits>&
621 operator<<(basic_ostream<wchar_t, _Traits>&, char8_t) = delete;
622#endif // _GLIBCXX_USE_CHAR8_T
623
624 template<typename _Traits>
625 basic_ostream<wchar_t, _Traits>&
626 operator<<(basic_ostream<wchar_t, _Traits>&, char16_t) = delete;
627
628 template<typename _Traits>
629 basic_ostream<wchar_t, _Traits>&
630 operator<<(basic_ostream<wchar_t, _Traits>&, char32_t) = delete;
631#endif // _GLIBCXX_USE_WCHAR_T
632#endif // C++20
633 ///@}
634
635 ///@{
636 /**
637 * @brief String inserters
638 * @param __out An output stream.
639 * @param __s A character string.
640 * @return out
641 * @pre @p __s must be a non-NULL pointer
642 *
643 * Behaves like one of the formatted arithmetic inserters described in
644 * std::basic_ostream. After constructing a sentry object with good
645 * status, this function inserts @c traits::length(__s) characters starting
646 * at @p __s, widened if necessary, followed by any required padding (as
647 * determined by [22.2.2.2.2]). @c __out.width(0) is then called.
648 */
649 template<typename _CharT, typename _Traits>
650 inline basic_ostream<_CharT, _Traits>&
651 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
652 {
653 if (!__s)
654 __out.setstate(ios_base::badbit);
655 else
656 __ostream_insert(__out, __s,
657 static_cast<streamsize>(_Traits::length(__s)));
658 return __out;
659 }
660
661 template<typename _CharT, typename _Traits>
662 basic_ostream<_CharT, _Traits> &
663 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
664
665 // Partial specializations
666 template<typename _Traits>
667 inline basic_ostream<char, _Traits>&
668 operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
669 {
670 if (!__s)
671 __out.setstate(ios_base::badbit);
672 else
673 __ostream_insert(__out, __s,
674 static_cast<streamsize>(_Traits::length(__s)));
675 return __out;
676 }
677
678 // Signed and unsigned
679 template<typename _Traits>
680 inline basic_ostream<char, _Traits>&
681 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
682 { return (__out << reinterpret_cast<const char*>(__s)); }
683
684 template<typename _Traits>
685 inline basic_ostream<char, _Traits> &
686 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
687 { return (__out << reinterpret_cast<const char*>(__s)); }
688
689#if __cplusplus > 201703L
690 // The following deleted overloads prevent formatting strings as
691 // pointer values.
692
693 template<typename _Traits>
694 basic_ostream<char, _Traits>&
695 operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete;
696
697#ifdef _GLIBCXX_USE_CHAR8_T
698 template<typename _Traits>
699 basic_ostream<char, _Traits>&
700 operator<<(basic_ostream<char, _Traits>&, const char8_t*) = delete;
701#endif // _GLIBCXX_USE_CHAR8_T
702
703 template<typename _Traits>
704 basic_ostream<char, _Traits>&
705 operator<<(basic_ostream<char, _Traits>&, const char16_t*) = delete;
706
707 template<typename _Traits>
708 basic_ostream<char, _Traits>&
709 operator<<(basic_ostream<char, _Traits>&, const char32_t*) = delete;
710
711#ifdef _GLIBCXX_USE_WCHAR_T
712#ifdef _GLIBCXX_USE_CHAR8_T
713 template<typename _Traits>
714 basic_ostream<wchar_t, _Traits>&
715 operator<<(basic_ostream<wchar_t, _Traits>&, const char8_t*) = delete;
716#endif
717
718 template<typename _Traits>
719 basic_ostream<wchar_t, _Traits>&
720 operator<<(basic_ostream<wchar_t, _Traits>&, const char16_t*) = delete;
721
722 template<typename _Traits>
723 basic_ostream<wchar_t, _Traits>&
724 operator<<(basic_ostream<wchar_t, _Traits>&, const char32_t*) = delete;
725#endif // _GLIBCXX_USE_WCHAR_T
726#endif // C++20
727 ///@}
728
729 // Standard basic_ostream manipulators
730
731 /**
732 * @brief Write a newline and flush the stream.
733 *
734 * This manipulator is often mistakenly used when a simple newline is
735 * desired, leading to poor buffering performance. See
736 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
737 * for more on this subject.
738 */
739 template<typename _CharT, typename _Traits>
740 inline basic_ostream<_CharT, _Traits>&
741 endl(basic_ostream<_CharT, _Traits>& __os)
742 { return flush(__os.put(__os.widen('\n'))); }
743
744 /**
745 * @brief Write a null character into the output sequence.
746 *
747 * <em>Null character</em> is @c CharT() by definition. For CharT
748 * of @c char, this correctly writes the ASCII @c NUL character
749 * string terminator.
750 */
751 template<typename _CharT, typename _Traits>
752 inline basic_ostream<_CharT, _Traits>&
753 ends(basic_ostream<_CharT, _Traits>& __os)
754 { return __os.put(_CharT()); }
755
756 /**
757 * @brief Flushes the output stream.
758 *
759 * This manipulator simply calls the stream's @c flush() member function.
760 */
761 template<typename _CharT, typename _Traits>
762 inline basic_ostream<_CharT, _Traits>&
763 flush(basic_ostream<_CharT, _Traits>& __os)
764 { return __os.flush(); }
765
766#if __cplusplus >= 201103L
767 // C++11 27.7.3.9 Rvalue stream insertion [ostream.rvalue]
768 // _GLIBCXX_RESOLVE_LIB_DEFECTS
769 // 1203. More useful rvalue stream insertion
770
771#if __cpp_concepts >= 201907L
772 // Use concepts if possible because they're cheaper to evaluate.
773 template<typename _Tp>
774 concept __derived_from_ios_base = is_class_v<_Tp>
775 && (!is_same_v<_Tp, ios_base>)
776 && requires (_Tp* __t, ios_base* __b) { __b = __t; };
777
778 template<typename _Os, typename _Tp>
779 requires __derived_from_ios_base<_Os>
780 && requires (_Os& __os, const _Tp& __t) { __os << __t; }
781 using __rvalue_stream_insertion_t = _Os&&;
782#else
783 template<typename _Tp>
784 using _Require_derived_from_ios_base
785 = _Require<is_class<_Tp>, __not_<is_same<_Tp, ios_base>>,
786 is_convertible<typename add_pointer<_Tp>::type, ios_base*>>;
787
788 template<typename _Os, typename _Tp,
789 typename = _Require_derived_from_ios_base<_Os>,
790 typename
791 = decltype(std::declval<_Os&>() << std::declval<const _Tp&>())>
792 using __rvalue_stream_insertion_t = _Os&&;
793#endif
794
795 /**
796 * @brief Generic inserter for rvalue stream
797 * @param __os An input stream.
798 * @param __x A reference to the object being inserted.
799 * @return __os
800 *
801 * This is just a forwarding function to allow insertion to
802 * rvalue streams since they won't bind to the inserter functions
803 * that take an lvalue reference.
804 */
805 template<typename _Ostream, typename _Tp>
806 inline __rvalue_stream_insertion_t<_Ostream, _Tp>
807 operator<<(_Ostream&& __os, const _Tp& __x)
808 {
809 __os << __x;
810 return std::move(__os);
811 }
812
813#ifdef __glibcxx_syncbuf // C++ >= 20 && HOSTED && CXX11ABI
814 template<typename _CharT, typename _Traits>
815 class __syncbuf_base : public basic_streambuf<_CharT, _Traits>
816 {
817 public:
818 static bool*
819 _S_get(basic_streambuf<_CharT, _Traits>* __buf [[maybe_unused]]) noexcept
820 {
821#if __cpp_rtti
822 if (auto __p = dynamic_cast<__syncbuf_base*>(__buf))
823 return &__p->_M_emit_on_sync;
824#endif
825 return nullptr;
826 }
827
828 protected:
829 __syncbuf_base(basic_streambuf<_CharT, _Traits>* __w = nullptr)
830 : _M_wrapped(__w)
831 { }
832
833 basic_streambuf<_CharT, _Traits>* _M_wrapped = nullptr;
834 bool _M_emit_on_sync = false;
835 bool _M_needs_sync = false;
836 };
837
838 template<typename _CharT, typename _Traits>
839 inline basic_ostream<_CharT, _Traits>&
840 emit_on_flush(basic_ostream<_CharT, _Traits>& __os)
841 {
842 if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
843 *__flag = true;
844 return __os;
845 }
846
847 template<typename _CharT, typename _Traits>
848 inline basic_ostream<_CharT, _Traits>&
849 noemit_on_flush(basic_ostream<_CharT, _Traits>& __os)
850 {
851 if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
852 *__flag = false;
853 return __os;
854 }
855
856 template<typename _CharT, typename _Traits>
857 inline basic_ostream<_CharT, _Traits>&
858 flush_emit(basic_ostream<_CharT, _Traits>& __os)
859 {
860 struct _Restore
861 {
862 ~_Restore() { *_M_flag = _M_prev; }
863
864 bool _M_prev = false;
865 bool* _M_flag = &_M_prev;
866 } __restore;
867
868 if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
869 {
870 __restore._M_prev = *__flag;
871 __restore._M_flag = __flag;
872 *__flag = true;
873 }
874
875 __os.flush();
876 return __os;
877 }
878#endif // __glibcxx_syncbuf
879
880#if __cpp_lib_print // C++ >= 23
881
882 inline void
883 vprint_nonunicode(ostream& __os, string_view __fmt, format_args __args)
884 {
885 ostream::sentry __cerb(__os);
886 if (__cerb)
887 {
888 __format::_Str_sink<char> __buf;
889 std::vformat_to(__buf.out(), __os.getloc(), __fmt, __args);
890 auto __out = __buf.view();
891
892 __try
893 {
894 std::__ostream_write(__os, __out.data(), __out.size());
895 }
896 __catch(const __cxxabiv1::__forced_unwind&)
897 {
898 __os._M_setstate(ios_base::badbit);
899 __throw_exception_again;
900 }
901 __catch(...)
902 { __os._M_setstate(ios_base::badbit); }
903 }
904 }
905
906 inline void
907 vprint_unicode(ostream& __os, string_view __fmt, format_args __args)
908 {
909#if !defined(_WIN32) || defined(__CYGWIN__)
910 // For most targets we don't need to do anything special to write
911 // Unicode to a terminal.
912 std::vprint_nonunicode(__os, __fmt, __args);
913#else
914 ostream::sentry __cerb(__os);
915 if (__cerb)
916 {
917 __format::_Str_sink<char> __buf;
918 std::vformat_to(__buf.out(), __os.getloc(), __fmt, __args);
919 auto __out = __buf.view();
920
921 void* __open_terminal(streambuf*);
922 error_code __write_to_terminal(void*, span<char>);
923 // If stream refers to a terminal, write a Unicode string to it.
924 if (auto __term = __open_terminal(__os.rdbuf()))
925 {
926#if !defined(_WIN32) || defined(__CYGWIN__)
927 // For POSIX, __open_terminal(streambuf*) uses fdopen to open a
928 // new file, so we would need to close it here. This code is not
929 // actually compiled because it's inside an #ifdef _WIN32 group,
930 // but just in case that changes in future ...
931 struct _Guard
932 {
933 _Guard(void* __p) : _M_f((FILE*)__p) { }
934 ~_Guard() { std::fclose(_M_f); }
935 _Guard(_Guard&&) = delete;
936 _Guard& operator=(_Guard&&) = delete;
937 FILE* _M_f;
938 };
939 _Guard __g(__term);
940#endif
941
942 ios_base::iostate __err = ios_base::goodbit;
943 __try
944 {
945 if (__os.rdbuf()->pubsync() == -1)
946 __err = ios::badbit;
947 else if (auto __e = __write_to_terminal(__term, __out))
948 if (__e != std::make_error_code(errc::illegal_byte_sequence))
949 __err = ios::badbit;
950 }
951 __catch(const __cxxabiv1::__forced_unwind&)
952 {
953 __os._M_setstate(ios_base::badbit);
954 __throw_exception_again;
955 }
956 __catch(...)
957 { __os._M_setstate(ios_base::badbit); }
958
959 if (__err)
960 __os.setstate(__err);
961 return;
962 }
963
964 // Otherwise just insert the string as vprint_nonunicode does.
965 __try
966 {
967 std::__ostream_write(__os, __out.data(), __out.size());
968 }
969 __catch(const __cxxabiv1::__forced_unwind&)
970 {
971 __os._M_setstate(ios_base::badbit);
972 __throw_exception_again;
973 }
974 __catch(...)
975 { __os._M_setstate(ios_base::badbit); }
976 }
977#endif // _WIN32
978 }
979
980 template<typename... _Args>
981 inline void
982 print(ostream& __os, format_string<_Args...> __fmt, _Args&&... __args)
983 {
984 auto __fmtargs = std::make_format_args(__args...);
985 if constexpr (__unicode::__literal_encoding_is_utf8())
986 std::vprint_unicode(__os, __fmt.get(), __fmtargs);
987 else
988 std::vprint_nonunicode(__os, __fmt.get(), __fmtargs);
989 }
990
991 template<typename... _Args>
992 inline void
993 println(ostream& __os, format_string<_Args...> __fmt, _Args&&... __args)
994 {
995 std::print(__os, "{}\n",
996 std::format(__fmt, std::forward<_Args>(__args)...));
997 }
998
999 // Defined for C++26, supported as an extension to C++23.
1000 inline void println(ostream& __os)
1001 {
1002#if defined(_WIN32) && !defined(__CYGWIN__)
1003 if constexpr (__unicode::__literal_encoding_is_utf8())
1004 std::vprint_unicode(__os, "\n", std::make_format_args());
1005 else
1006#endif
1007 __os.put('\n');
1008 }
1009
1010#endif // __cpp_lib_print
1011
1012#endif // C++11
1013
1014_GLIBCXX_END_NAMESPACE_VERSION
1015} // namespace std
1016
1017#include <bits/ostream.tcc>
1018
1019#endif /* _GLIBCXX_OSTREAM */
1020