libstdc++
chrono.h
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1 // chrono::duration and chrono::time_point -*- C++ -*-
2 
3 // Copyright (C) 2008-2023 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
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22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file include/bits/chrono.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{chrono}
28  */
29 
30 #ifndef _GLIBCXX_CHRONO_H
31 #define _GLIBCXX_CHRONO_H 1
32 
33 #pragma GCC system_header
34 
35 #if __cplusplus >= 201103L
36 
37 #include <ratio>
38 #include <type_traits>
39 #include <limits>
40 #include <ctime>
41 #include <bits/parse_numbers.h> // for literals support.
42 #if __cplusplus >= 202002L
43 # include <concepts>
44 # include <compare>
45 #endif
46 
47 namespace std _GLIBCXX_VISIBILITY(default)
48 {
49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 
51 #if __cplusplus >= 201703L
52  namespace filesystem { struct __file_clock; };
53 #endif
54 
55  namespace chrono
56  {
57  /// @addtogroup chrono
58  /// @{
59 
60  /// `chrono::duration` represents a distance between two points in time
61  template<typename _Rep, typename _Period = ratio<1>>
62  class duration;
63 
64  /// `chrono::time_point` represents a point in time as measured by a clock
65  template<typename _Clock, typename _Dur = typename _Clock::duration>
66  class time_point;
67  /// @}
68  }
69 
70  /// @addtogroup chrono
71  /// @{
72 
73  // 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
74 
75  /// @cond undocumented
76 
77  template<typename _CT, typename _Period1, typename _Period2, typename = void>
78  struct __duration_common_type
79  { };
80 
81  template<typename _CT, typename _Period1, typename _Period2>
82  struct __duration_common_type<_CT, _Period1, _Period2,
83  __void_t<typename _CT::type>>
84  {
85  private:
86  using __gcd_num = __static_gcd<_Period1::num, _Period2::num>;
87  using __gcd_den = __static_gcd<_Period1::den, _Period2::den>;
88  using __cr = typename _CT::type;
89  using __r = ratio<__gcd_num::value,
90  (_Period1::den / __gcd_den::value) * _Period2::den>;
91 
92  public:
94  };
95 
96  /// @endcond
97 
98  /// @{
99  /// @relates chrono::duration
100 
101  /// Specialization of common_type for chrono::duration types.
102  template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
103  struct common_type<chrono::duration<_Rep1, _Period1>,
104  chrono::duration<_Rep2, _Period2>>
105  : __duration_common_type<common_type<_Rep1, _Rep2>,
106  typename _Period1::type,
107  typename _Period2::type>
108  { };
109 
110  /// Specialization of common_type for two identical chrono::duration types.
111  template<typename _Rep, typename _Period>
112  struct common_type<chrono::duration<_Rep, _Period>,
113  chrono::duration<_Rep, _Period>>
114  {
116  typename _Period::type>;
117  };
118 
119  /// Specialization of common_type for one chrono::duration type.
120  template<typename _Rep, typename _Period>
121  struct common_type<chrono::duration<_Rep, _Period>>
122  {
124  typename _Period::type>;
125  };
126  /// @}
127 
128  // 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
129 
130  /// @cond undocumented
131 
132  template<typename _CT, typename _Clock, typename = void>
133  struct __timepoint_common_type
134  { };
135 
136  template<typename _CT, typename _Clock>
137  struct __timepoint_common_type<_CT, _Clock, __void_t<typename _CT::type>>
138  {
139  using type = chrono::time_point<_Clock, typename _CT::type>;
140  };
141 
142  /// @endcond
143 
144  /// @{
145  /// @relates chrono::time_point
146 
147  /// Specialization of common_type for chrono::time_point types.
148  template<typename _Clock, typename _Duration1, typename _Duration2>
149  struct common_type<chrono::time_point<_Clock, _Duration1>,
150  chrono::time_point<_Clock, _Duration2>>
151  : __timepoint_common_type<common_type<_Duration1, _Duration2>, _Clock>
152  { };
153 
154  /// Specialization of common_type for two identical chrono::time_point types.
155  template<typename _Clock, typename _Duration>
156  struct common_type<chrono::time_point<_Clock, _Duration>,
157  chrono::time_point<_Clock, _Duration>>
159 
160  /// Specialization of common_type for one chrono::time_point type.
161  template<typename _Clock, typename _Duration>
162  struct common_type<chrono::time_point<_Clock, _Duration>>
164  /// @}
165 
166  /// @} group chrono
167 
168  namespace chrono
169  {
170  /// @addtogroup chrono
171  /// @{
172 
173  /// @cond undocumented
174 
175  // Primary template for duration_cast impl.
176  template<typename _ToDur, typename _CF, typename _CR,
177  bool _NumIsOne = false, bool _DenIsOne = false>
178  struct __duration_cast_impl
179  {
180  template<typename _Rep, typename _Period>
181  static constexpr _ToDur
182  __cast(const duration<_Rep, _Period>& __d)
183  {
184  typedef typename _ToDur::rep __to_rep;
185  return _ToDur(static_cast<__to_rep>(static_cast<_CR>(__d.count())
186  * static_cast<_CR>(_CF::num)
187  / static_cast<_CR>(_CF::den)));
188  }
189  };
190 
191  template<typename _ToDur, typename _CF, typename _CR>
192  struct __duration_cast_impl<_ToDur, _CF, _CR, true, true>
193  {
194  template<typename _Rep, typename _Period>
195  static constexpr _ToDur
196  __cast(const duration<_Rep, _Period>& __d)
197  {
198  typedef typename _ToDur::rep __to_rep;
199  return _ToDur(static_cast<__to_rep>(__d.count()));
200  }
201  };
202 
203  template<typename _ToDur, typename _CF, typename _CR>
204  struct __duration_cast_impl<_ToDur, _CF, _CR, true, false>
205  {
206  template<typename _Rep, typename _Period>
207  static constexpr _ToDur
208  __cast(const duration<_Rep, _Period>& __d)
209  {
210  typedef typename _ToDur::rep __to_rep;
211  return _ToDur(static_cast<__to_rep>(
212  static_cast<_CR>(__d.count()) / static_cast<_CR>(_CF::den)));
213  }
214  };
215 
216  template<typename _ToDur, typename _CF, typename _CR>
217  struct __duration_cast_impl<_ToDur, _CF, _CR, false, true>
218  {
219  template<typename _Rep, typename _Period>
220  static constexpr _ToDur
221  __cast(const duration<_Rep, _Period>& __d)
222  {
223  typedef typename _ToDur::rep __to_rep;
224  return _ToDur(static_cast<__to_rep>(
225  static_cast<_CR>(__d.count()) * static_cast<_CR>(_CF::num)));
226  }
227  };
228 
229  template<typename _Tp>
230  struct __is_duration
232  { };
233 
234  template<typename _Rep, typename _Period>
235  struct __is_duration<duration<_Rep, _Period>>
237  { };
238 
239  template<typename _Tp>
240  using __enable_if_is_duration
241  = typename enable_if<__is_duration<_Tp>::value, _Tp>::type;
242 
243  template<typename _Tp>
244  using __disable_if_is_duration
245  = typename enable_if<!__is_duration<_Tp>::value, _Tp>::type;
246 
247 #if __cplusplus >= 201703L
248  template<typename _Tp>
249  inline constexpr bool __is_duration_v = false;
250  template<typename _Rep, typename _Period>
251  inline constexpr bool __is_duration_v<duration<_Rep, _Period>> = true;
252  template<typename _Tp>
253  inline constexpr bool __is_time_point_v = false;
254  template<typename _Clock, typename _Dur>
255  inline constexpr bool __is_time_point_v<time_point<_Clock, _Dur>> = true;
256 #endif
257 
258  /// @endcond
259 
260  /** Convert a `duration` to type `ToDur`.
261  *
262  * If the duration cannot be represented accurately in the result type,
263  * returns the result of integer truncation (i.e., rounded towards zero).
264  *
265  * @tparam _ToDur The result type must be a `duration`.
266  * @param __d A duration.
267  * @return The value of `__d` converted to type `_ToDur`.
268  * @since C++11
269  */
270  template<typename _ToDur, typename _Rep, typename _Period>
271  _GLIBCXX_NODISCARD
272  constexpr __enable_if_is_duration<_ToDur>
274  {
275 #if __cpp_inline_variables && __cpp_if_constexpr
276  if constexpr (is_same_v<_ToDur, duration<_Rep, _Period>>)
277  return __d;
278  else
279  {
280 #endif
281  using __to_period = typename _ToDur::period;
282  using __to_rep = typename _ToDur::rep;
284  using __cr = typename common_type<__to_rep, _Rep, intmax_t>::type;
285  using __dc = __duration_cast_impl<_ToDur, __cf, __cr,
286  __cf::num == 1, __cf::den == 1>;
287  return __dc::__cast(__d);
288 #if __cpp_inline_variables && __cpp_if_constexpr
289  }
290 #endif
291  }
292 
293  /** Trait indicating whether to treat a type as a floating-point type.
294  *
295  * The chrono library uses this trait to tell whether a `duration` can
296  * represent fractional values of the given precision, or only integral
297  * values.
298  *
299  * You should specialize this trait for your own numeric types that are
300  * used with `duration` and can represent non-integral values.
301  *
302  * @since C++11
303  */
304  template<typename _Rep>
306  : is_floating_point<_Rep>
307  { };
308 
309 #if __cplusplus > 201402L
310  template <typename _Rep>
311  inline constexpr bool treat_as_floating_point_v =
313 
314  template<>
315  inline constexpr bool treat_as_floating_point_v<int> = false;
316  template<>
317  inline constexpr bool treat_as_floating_point_v<long> = false;
318  template<>
319  inline constexpr bool treat_as_floating_point_v<long long> = false;
320  template<>
321  inline constexpr bool treat_as_floating_point_v<float> = true;
322  template<>
323  inline constexpr bool treat_as_floating_point_v<double> = true;
324  template<>
325  inline constexpr bool treat_as_floating_point_v<long double> = true;
326 #endif // C++17
327 
328 #if __cplusplus > 201703L
329 #if __cpp_lib_concepts
330  template<typename _Tp>
331  inline constexpr bool is_clock_v = false;
332 
333  template<typename _Tp>
334  requires requires {
335  typename _Tp::rep;
336  typename _Tp::period;
337  typename _Tp::duration;
338  typename _Tp::time_point::clock;
339  typename _Tp::time_point::duration;
340  { &_Tp::is_steady } -> same_as<const bool*>;
341  { _Tp::now() } -> same_as<typename _Tp::time_point>;
342  requires same_as<typename _Tp::duration,
343  duration<typename _Tp::rep, typename _Tp::period>>;
344  requires same_as<typename _Tp::time_point::duration,
345  typename _Tp::duration>;
346  }
347  inline constexpr bool is_clock_v<_Tp> = true;
348 #else
349  template<typename _Tp, typename = void>
350  inline constexpr bool is_clock_v = false;
351 
352  template<typename _Tp>
353  inline constexpr bool
354  is_clock_v<_Tp, void_t<typename _Tp::rep, typename _Tp::period,
355  typename _Tp::duration,
356  typename _Tp::time_point::duration,
357  decltype(_Tp::is_steady),
358  decltype(_Tp::now())>>
359  = __and_v<is_same<typename _Tp::duration,
360  duration<typename _Tp::rep, typename _Tp::period>>,
361  is_same<typename _Tp::time_point::duration,
362  typename _Tp::duration>,
363  is_same<decltype(&_Tp::is_steady), const bool*>,
364  is_same<decltype(_Tp::now()), typename _Tp::time_point>>;
365 #endif
366 
367  template<typename _Tp>
368  struct is_clock
369  : bool_constant<is_clock_v<_Tp>>
370  { };
371 #endif // C++20
372 
373 #if __cplusplus >= 201703L
374 # define __cpp_lib_chrono 201611L
375 
376  /** Convert a `duration` to type `ToDur` and round down.
377  *
378  * If the duration cannot be represented exactly in the result type,
379  * returns the closest value that is less than the argument.
380  *
381  * @tparam _ToDur The result type must be a `duration`.
382  * @param __d A duration.
383  * @return The value of `__d` converted to type `_ToDur`.
384  * @since C++17
385  */
386  template<typename _ToDur, typename _Rep, typename _Period>
387  [[nodiscard]] constexpr __enable_if_is_duration<_ToDur>
389  {
390  auto __to = chrono::duration_cast<_ToDur>(__d);
391  if (__to > __d)
392  return __to - _ToDur{1};
393  return __to;
394  }
395 
396  /** Convert a `duration` to type `ToDur` and round up.
397  *
398  * If the duration cannot be represented exactly in the result type,
399  * returns the closest value that is greater than the argument.
400  *
401  * @tparam _ToDur The result type must be a `duration`.
402  * @param __d A duration.
403  * @return The value of `__d` converted to type `_ToDur`.
404  * @since C++17
405  */
406  template<typename _ToDur, typename _Rep, typename _Period>
407  [[nodiscard]] constexpr __enable_if_is_duration<_ToDur>
409  {
410  auto __to = chrono::duration_cast<_ToDur>(__d);
411  if (__to < __d)
412  return __to + _ToDur{1};
413  return __to;
414  }
415 
416  /** Convert a `duration` to type `ToDur` and round to the closest value.
417  *
418  * If the duration cannot be represented exactly in the result type,
419  * returns the closest value, rounding ties to even.
420  *
421  * @tparam _ToDur The result type must be a `duration` with a
422  * non-floating-point `rep` type.
423  * @param __d A duration.
424  * @return The value of `__d` converted to type `_ToDur`.
425  * @since C++17
426  */
427  template <typename _ToDur, typename _Rep, typename _Period>
428  [[nodiscard]] constexpr
429  enable_if_t<
430  __and_<__is_duration<_ToDur>,
431  __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
432  _ToDur>
434  {
435  _ToDur __t0 = chrono::floor<_ToDur>(__d);
436  _ToDur __t1 = __t0 + _ToDur{1};
437  auto __diff0 = __d - __t0;
438  auto __diff1 = __t1 - __d;
439  if (__diff0 == __diff1)
440  {
441  if (__t0.count() & 1)
442  return __t1;
443  return __t0;
444  }
445  else if (__diff0 < __diff1)
446  return __t0;
447  return __t1;
448  }
449 
450  /** The absolute (non-negative) value of a duration.
451  *
452  * @param __d A duration with a signed `rep` type.
453  * @return A duration of the same type as the argument, with value |d|.
454  * @since C++17
455  */
456  template<typename _Rep, typename _Period>
457  [[nodiscard]] constexpr
458  enable_if_t<numeric_limits<_Rep>::is_signed, duration<_Rep, _Period>>
460  {
461  if (__d >= __d.zero())
462  return __d;
463  return -__d;
464  }
465 
466  // Make chrono::ceil<D> also usable as chrono::__detail::ceil<D>.
467  namespace __detail { using chrono::ceil; }
468 
469 #else // ! C++17
470 
471  // We want to use ceil even when compiling for earlier standards versions.
472  // C++11 only allows a single statement in a constexpr function, so we
473  // need to move the comparison into a separate function, __ceil_impl.
474  namespace __detail
475  {
476  template<typename _Tp, typename _Up>
477  constexpr _Tp
478  __ceil_impl(const _Tp& __t, const _Up& __u)
479  {
480  return (__t < __u) ? (__t + _Tp{1}) : __t;
481  }
482 
483  // C++11-friendly version of std::chrono::ceil<D> for internal use.
484  template<typename _ToDur, typename _Rep, typename _Period>
485  constexpr _ToDur
486  ceil(const duration<_Rep, _Period>& __d)
487  {
488  return __detail::__ceil_impl(chrono::duration_cast<_ToDur>(__d), __d);
489  }
490  }
491 #endif // C++17
492 
493  /// duration_values
494  template<typename _Rep>
496  {
497  static constexpr _Rep
498  zero() noexcept
499  { return _Rep(0); }
500 
501  static constexpr _Rep
502  max() noexcept
503  { return numeric_limits<_Rep>::max(); }
504 
505  static constexpr _Rep
506  min() noexcept
507  { return numeric_limits<_Rep>::lowest(); }
508  };
509 
510  template<typename _Rep, typename _Period>
511  class duration
512  {
513  static_assert(!__is_duration<_Rep>::value,
514  "rep cannot be a std::chrono::duration");
515  static_assert(__is_ratio<_Period>::value,
516  "period must be a specialization of std::ratio");
517  static_assert(_Period::num > 0, "period must be positive");
518 
519  template<typename _Rep2>
520  using __is_float = treat_as_floating_point<_Rep2>;
521 
522  static constexpr intmax_t
523  _S_gcd(intmax_t __m, intmax_t __n) noexcept
524  {
525  // Duration only allows positive periods so we don't need to
526  // handle negative values here (unlike __static_gcd and std::gcd).
527 #if __cplusplus >= 201402L
528  do
529  {
530  intmax_t __rem = __m % __n;
531  __m = __n;
532  __n = __rem;
533  }
534  while (__n != 0);
535  return __m;
536 #else
537  // C++11 doesn't allow loops in constexpr functions, but this
538  // recursive version can be more expensive to evaluate.
539  return (__n == 0) ? __m : _S_gcd(__n, __m % __n);
540 #endif
541  }
542 
543  // _GLIBCXX_RESOLVE_LIB_DEFECTS
544  // 2094. overflow shouldn't participate in overload resolution
545  // 3090. What is [2094] intended to mean?
546  // This only produces a valid type if no overflow occurs.
547  template<typename _R1, typename _R2,
548  intmax_t __gcd1 = _S_gcd(_R1::num, _R2::num),
549  intmax_t __gcd2 = _S_gcd(_R1::den, _R2::den)>
550  using __divide = ratio<(_R1::num / __gcd1) * (_R2::den / __gcd2),
551  (_R1::den / __gcd2) * (_R2::num / __gcd1)>;
552 
553  // _Period2 is an exact multiple of _Period
554  template<typename _Period2>
555  using __is_harmonic
556  = __bool_constant<__divide<_Period2, _Period>::den == 1>;
557 
558  public:
559 
560  using rep = _Rep;
561  using period = typename _Period::type;
562 
563  // 20.11.5.1 construction / copy / destroy
564  constexpr duration() = default;
565 
566  duration(const duration&) = default;
567 
568  // _GLIBCXX_RESOLVE_LIB_DEFECTS
569  // 3050. Conversion specification problem in chrono::duration
570  template<typename _Rep2, typename = _Require<
571  is_convertible<const _Rep2&, rep>,
572  __or_<__is_float<rep>, __not_<__is_float<_Rep2>>>>>
573  constexpr explicit duration(const _Rep2& __rep)
574  : __r(static_cast<rep>(__rep)) { }
575 
576  template<typename _Rep2, typename _Period2, typename = _Require<
577  is_convertible<const _Rep2&, rep>,
578  __or_<__is_float<rep>,
579  __and_<__is_harmonic<_Period2>,
580  __not_<__is_float<_Rep2>>>>>>
581  constexpr duration(const duration<_Rep2, _Period2>& __d)
582  : __r(duration_cast<duration>(__d).count()) { }
583 
584  ~duration() = default;
585  duration& operator=(const duration&) = default;
586 
587  // 20.11.5.2 observer
588  constexpr rep
589  count() const
590  { return __r; }
591 
592  // 20.11.5.3 arithmetic
593 
594  constexpr duration<typename common_type<rep>::type, period>
595  operator+() const
596  { return duration<typename common_type<rep>::type, period>(__r); }
597 
598  constexpr duration<typename common_type<rep>::type, period>
599  operator-() const
600  { return duration<typename common_type<rep>::type, period>(-__r); }
601 
602  _GLIBCXX17_CONSTEXPR duration&
603  operator++()
604  {
605  ++__r;
606  return *this;
607  }
608 
609  _GLIBCXX17_CONSTEXPR duration
610  operator++(int)
611  { return duration(__r++); }
612 
613  _GLIBCXX17_CONSTEXPR duration&
614  operator--()
615  {
616  --__r;
617  return *this;
618  }
619 
620  _GLIBCXX17_CONSTEXPR duration
621  operator--(int)
622  { return duration(__r--); }
623 
624  _GLIBCXX17_CONSTEXPR duration&
625  operator+=(const duration& __d)
626  {
627  __r += __d.count();
628  return *this;
629  }
630 
631  _GLIBCXX17_CONSTEXPR duration&
632  operator-=(const duration& __d)
633  {
634  __r -= __d.count();
635  return *this;
636  }
637 
638  _GLIBCXX17_CONSTEXPR duration&
639  operator*=(const rep& __rhs)
640  {
641  __r *= __rhs;
642  return *this;
643  }
644 
645  _GLIBCXX17_CONSTEXPR duration&
646  operator/=(const rep& __rhs)
647  {
648  __r /= __rhs;
649  return *this;
650  }
651 
652  // DR 934.
653  template<typename _Rep2 = rep>
654  _GLIBCXX17_CONSTEXPR
655  __enable_if_t<!treat_as_floating_point<_Rep2>::value, duration&>
656  operator%=(const rep& __rhs)
657  {
658  __r %= __rhs;
659  return *this;
660  }
661 
662  template<typename _Rep2 = rep>
663  _GLIBCXX17_CONSTEXPR
664  __enable_if_t<!treat_as_floating_point<_Rep2>::value, duration&>
665  operator%=(const duration& __d)
666  {
667  __r %= __d.count();
668  return *this;
669  }
670 
671  // 20.11.5.4 special values
672  static constexpr duration
673  zero() noexcept
674  { return duration(duration_values<rep>::zero()); }
675 
676  static constexpr duration
677  min() noexcept
678  { return duration(duration_values<rep>::min()); }
679 
680  static constexpr duration
681  max() noexcept
682  { return duration(duration_values<rep>::max()); }
683 
684  private:
685  rep __r;
686  };
687 
688  /// @{
689  /// @relates std::chrono::duration
690 
691  /// The sum of two durations.
692  template<typename _Rep1, typename _Period1,
693  typename _Rep2, typename _Period2>
694  constexpr typename common_type<duration<_Rep1, _Period1>,
695  duration<_Rep2, _Period2>>::type
697  const duration<_Rep2, _Period2>& __rhs)
698  {
699  typedef duration<_Rep1, _Period1> __dur1;
700  typedef duration<_Rep2, _Period2> __dur2;
701  typedef typename common_type<__dur1,__dur2>::type __cd;
702  return __cd(__cd(__lhs).count() + __cd(__rhs).count());
703  }
704 
705  /// The difference between two durations.
706  template<typename _Rep1, typename _Period1,
707  typename _Rep2, typename _Period2>
708  constexpr typename common_type<duration<_Rep1, _Period1>,
711  const duration<_Rep2, _Period2>& __rhs)
712  {
713  typedef duration<_Rep1, _Period1> __dur1;
714  typedef duration<_Rep2, _Period2> __dur2;
715  typedef typename common_type<__dur1,__dur2>::type __cd;
716  return __cd(__cd(__lhs).count() - __cd(__rhs).count());
717  }
718 
719  /// @}
720 
721  /// @cond undocumented
722 
723  // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
724  // is implicitly convertible to it.
725  // _GLIBCXX_RESOLVE_LIB_DEFECTS
726  // 3050. Conversion specification problem in chrono::duration constructor
727  template<typename _Rep1, typename _Rep2,
728  typename _CRep = typename common_type<_Rep1, _Rep2>::type>
729  using __common_rep_t = typename
731 
732  /// @endcond
733 
734  /** @{
735  * Arithmetic operators for chrono::duration
736  * @relates std::chrono::duration
737  */
738 
739  template<typename _Rep1, typename _Period, typename _Rep2>
740  constexpr duration<__common_rep_t<_Rep1, _Rep2>, _Period>
741  operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
742  {
744  __cd;
745  return __cd(__cd(__d).count() * __s);
746  }
747 
748  template<typename _Rep1, typename _Rep2, typename _Period>
749  constexpr duration<__common_rep_t<_Rep2, _Rep1>, _Period>
750  operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
751  { return __d * __s; }
752 
753  template<typename _Rep1, typename _Period, typename _Rep2>
754  constexpr
755  duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
756  operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
757  {
759  __cd;
760  return __cd(__cd(__d).count() / __s);
761  }
762 
763  template<typename _Rep1, typename _Period1,
764  typename _Rep2, typename _Period2>
765  constexpr typename common_type<_Rep1, _Rep2>::type
767  const duration<_Rep2, _Period2>& __rhs)
768  {
769  typedef duration<_Rep1, _Period1> __dur1;
770  typedef duration<_Rep2, _Period2> __dur2;
771  typedef typename common_type<__dur1,__dur2>::type __cd;
772  return __cd(__lhs).count() / __cd(__rhs).count();
773  }
774 
775  // DR 934.
776  template<typename _Rep1, typename _Period, typename _Rep2>
777  constexpr
778  duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
779  operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
780  {
782  __cd;
783  return __cd(__cd(__d).count() % __s);
784  }
785 
786  template<typename _Rep1, typename _Period1,
787  typename _Rep2, typename _Period2>
788  constexpr typename common_type<duration<_Rep1, _Period1>,
789  duration<_Rep2, _Period2>>::type
791  const duration<_Rep2, _Period2>& __rhs)
792  {
793  typedef duration<_Rep1, _Period1> __dur1;
794  typedef duration<_Rep2, _Period2> __dur2;
795  typedef typename common_type<__dur1,__dur2>::type __cd;
796  return __cd(__cd(__lhs).count() % __cd(__rhs).count());
797  }
798  /// @}
799 
800  // comparisons
801 
802  /** @{
803  * Comparisons for chrono::duration
804  * @relates std::chrono::duration
805  */
806 
807  template<typename _Rep1, typename _Period1,
808  typename _Rep2, typename _Period2>
809  constexpr bool
811  const duration<_Rep2, _Period2>& __rhs)
812  {
813  typedef duration<_Rep1, _Period1> __dur1;
814  typedef duration<_Rep2, _Period2> __dur2;
815  typedef typename common_type<__dur1,__dur2>::type __ct;
816  return __ct(__lhs).count() == __ct(__rhs).count();
817  }
818 
819  template<typename _Rep1, typename _Period1,
820  typename _Rep2, typename _Period2>
821  constexpr bool
822  operator<(const duration<_Rep1, _Period1>& __lhs,
823  const duration<_Rep2, _Period2>& __rhs)
824  {
825  typedef duration<_Rep1, _Period1> __dur1;
826  typedef duration<_Rep2, _Period2> __dur2;
827  typedef typename common_type<__dur1,__dur2>::type __ct;
828  return __ct(__lhs).count() < __ct(__rhs).count();
829  }
830 
831 #if __cpp_lib_three_way_comparison
832  template<typename _Rep1, typename _Period1,
833  typename _Rep2, typename _Period2>
834  requires three_way_comparable<common_type_t<_Rep1, _Rep2>>
835  constexpr auto
836  operator<=>(const duration<_Rep1, _Period1>& __lhs,
837  const duration<_Rep2, _Period2>& __rhs)
838  {
840  duration<_Rep2, _Period2>>;
841  return __ct(__lhs).count() <=> __ct(__rhs).count();
842  }
843 #else
844  template<typename _Rep1, typename _Period1,
845  typename _Rep2, typename _Period2>
846  constexpr bool
848  const duration<_Rep2, _Period2>& __rhs)
849  { return !(__lhs == __rhs); }
850 #endif
851 
852  template<typename _Rep1, typename _Period1,
853  typename _Rep2, typename _Period2>
854  constexpr bool
855  operator<=(const duration<_Rep1, _Period1>& __lhs,
856  const duration<_Rep2, _Period2>& __rhs)
857  { return !(__rhs < __lhs); }
858 
859  template<typename _Rep1, typename _Period1,
860  typename _Rep2, typename _Period2>
861  constexpr bool
863  const duration<_Rep2, _Period2>& __rhs)
864  { return __rhs < __lhs; }
865 
866  template<typename _Rep1, typename _Period1,
867  typename _Rep2, typename _Period2>
868  constexpr bool
870  const duration<_Rep2, _Period2>& __rhs)
871  { return !(__lhs < __rhs); }
872 
873  /// @}
874 
875  /// @cond undocumented
876 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
877 # define _GLIBCXX_CHRONO_INT64_T int64_t
878 #elif defined __INT64_TYPE__
879 # define _GLIBCXX_CHRONO_INT64_T __INT64_TYPE__
880 #else
882  "Representation type for nanoseconds must have at least 64 bits");
883 # define _GLIBCXX_CHRONO_INT64_T long long
884 #endif
885  /// @endcond
886 
887  /// nanoseconds
889 
890  /// microseconds
892 
893  /// milliseconds
895 
896  /// seconds
898 
899  /// minutes
901 
902  /// hours
904 
905 #if __cplusplus > 201703L
906  /// days
908 
909  /// weeks
911 
912  /// years
914 
915  /// months
917 #endif // C++20
918 
919 #undef _GLIBCXX_CHRONO_INT64_T
920 
921  template<typename _Clock, typename _Dur>
922  class time_point
923  {
924  static_assert(__is_duration<_Dur>::value,
925  "duration must be a specialization of std::chrono::duration");
926 
927  public:
928  typedef _Clock clock;
929  typedef _Dur duration;
930  typedef typename duration::rep rep;
931  typedef typename duration::period period;
932 
933  constexpr time_point() : __d(duration::zero())
934  { }
935 
936  constexpr explicit time_point(const duration& __dur)
937  : __d(__dur)
938  { }
939 
940  // conversions
941  template<typename _Dur2,
942  typename = _Require<is_convertible<_Dur2, _Dur>>>
943  constexpr time_point(const time_point<clock, _Dur2>& __t)
944  : __d(__t.time_since_epoch())
945  { }
946 
947  // observer
948  constexpr duration
949  time_since_epoch() const
950  { return __d; }
951 
952 #if __cplusplus > 201703L
953  constexpr time_point&
954  operator++()
955  {
956  ++__d;
957  return *this;
958  }
959 
960  constexpr time_point
961  operator++(int)
962  { return time_point{__d++}; }
963 
964  constexpr time_point&
965  operator--()
966  {
967  --__d;
968  return *this;
969  }
970 
971  constexpr time_point
972  operator--(int)
973  { return time_point{__d--}; }
974 #endif
975 
976  // arithmetic
977  _GLIBCXX17_CONSTEXPR time_point&
978  operator+=(const duration& __dur)
979  {
980  __d += __dur;
981  return *this;
982  }
983 
984  _GLIBCXX17_CONSTEXPR time_point&
985  operator-=(const duration& __dur)
986  {
987  __d -= __dur;
988  return *this;
989  }
990 
991  // special values
992  static constexpr time_point
993  min() noexcept
994  { return time_point(duration::min()); }
995 
996  static constexpr time_point
997  max() noexcept
998  { return time_point(duration::max()); }
999 
1000  private:
1001  duration __d;
1002  };
1003 
1004  /** Convert a `time_point` to use `duration` type `ToDur`.
1005  *
1006  * The result is the same time point as measured by the same clock, but
1007  * using the specified `duration` to represent the time.
1008  * If the time point cannot be represented accurately in the result type,
1009  * returns the result of integer truncation (i.e., rounded towards zero).
1010  *
1011  * @tparam _ToDur The `duration` type to use for the result.
1012  * @param __t A time point.
1013  * @return The value of `__t` converted to use type `_ToDur`.
1014  * @since C++11
1015  */
1016  template<typename _ToDur, typename _Clock, typename _Dur>
1017  _GLIBCXX_NODISCARD constexpr
1018  __enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
1020  {
1021  typedef time_point<_Clock, _ToDur> __time_point;
1022  return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
1023  }
1024 
1025 #if __cplusplus > 201402L
1026  /** Convert a `time_point` to type `ToDur` and round down.
1027  *
1028  * The result is the same time point as measured by the same clock, but
1029  * using the specified `duration` to represent the time.
1030  * If the time point cannot be represented exactly in the result type,
1031  * returns the closest value that is less than the argument.
1032  *
1033  * @tparam _ToDur The `duration` type to use for the result.
1034  * @param __t A time point.
1035  * @return The value of `__d` converted to type `_ToDur`.
1036  * @since C++17
1037  */
1038  template<typename _ToDur, typename _Clock, typename _Dur>
1039  [[nodiscard]] constexpr
1040  enable_if_t<__is_duration_v<_ToDur>, time_point<_Clock, _ToDur>>
1042  {
1044  chrono::floor<_ToDur>(__tp.time_since_epoch())};
1045  }
1046 
1047  /** Convert a `time_point` to type `ToDur` and round up.
1048  *
1049  * The result is the same time point as measured by the same clock, but
1050  * using the specified `duration` to represent the time.
1051  * If the time point cannot be represented exactly in the result type,
1052  * returns the closest value that is greater than the argument.
1053  *
1054  * @tparam _ToDur The `duration` type to use for the result.
1055  * @param __t A time point.
1056  * @return The value of `__d` converted to type `_ToDur`.
1057  * @since C++17
1058  */
1059  template<typename _ToDur, typename _Clock, typename _Dur>
1060  [[nodiscard]] constexpr
1061  enable_if_t<__is_duration_v<_ToDur>, time_point<_Clock, _ToDur>>
1063  {
1065  chrono::ceil<_ToDur>(__tp.time_since_epoch())};
1066  }
1067 
1068  /** Convert a `time_point` to type `ToDur` and round to the closest value.
1069  *
1070  * The result is the same time point as measured by the same clock, but
1071  * using the specified `duration` to represent the time.
1072  * If the time point cannot be represented exactly in the result type,
1073  * returns the closest value, rounding ties to even.
1074  *
1075  * @tparam _ToDur The `duration` type to use for the result,
1076  * which must have a non-floating-point `rep` type.
1077  * @param __t A time point.
1078  * @return The value of `__d` converted to type `_ToDur`.
1079  * @since C++17
1080  */
1081  template<typename _ToDur, typename _Clock, typename _Dur>
1082  [[nodiscard]] constexpr
1084  && !treat_as_floating_point_v<typename _ToDur::rep>,
1085  time_point<_Clock, _ToDur>>
1087  {
1089  chrono::round<_ToDur>(__tp.time_since_epoch())};
1090  }
1091 #endif // C++17
1092 
1093  /// @{
1094  /// @relates time_point
1095 
1096  /// Adjust a time point forwards by the given duration.
1097  template<typename _Clock, typename _Dur1,
1098  typename _Rep2, typename _Period2>
1099  constexpr time_point<_Clock,
1102  const duration<_Rep2, _Period2>& __rhs)
1103  {
1104  typedef duration<_Rep2, _Period2> __dur2;
1105  typedef typename common_type<_Dur1,__dur2>::type __ct;
1106  typedef time_point<_Clock, __ct> __time_point;
1107  return __time_point(__lhs.time_since_epoch() + __rhs);
1108  }
1109 
1110  /// Adjust a time point forwards by the given duration.
1111  template<typename _Rep1, typename _Period1,
1112  typename _Clock, typename _Dur2>
1113  constexpr time_point<_Clock,
1114  typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
1116  const time_point<_Clock, _Dur2>& __rhs)
1117  {
1118  typedef duration<_Rep1, _Period1> __dur1;
1119  typedef typename common_type<__dur1,_Dur2>::type __ct;
1120  typedef time_point<_Clock, __ct> __time_point;
1121  return __time_point(__rhs.time_since_epoch() + __lhs);
1122  }
1123 
1124  /// Adjust a time point backwards by the given duration.
1125  template<typename _Clock, typename _Dur1,
1126  typename _Rep2, typename _Period2>
1127  constexpr time_point<_Clock,
1130  const duration<_Rep2, _Period2>& __rhs)
1131  {
1132  typedef duration<_Rep2, _Period2> __dur2;
1133  typedef typename common_type<_Dur1,__dur2>::type __ct;
1134  typedef time_point<_Clock, __ct> __time_point;
1135  return __time_point(__lhs.time_since_epoch() -__rhs);
1136  }
1137 
1138  /// The difference between two time points (as a duration)
1139  template<typename _Clock, typename _Dur1, typename _Dur2>
1140  constexpr typename common_type<_Dur1, _Dur2>::type
1142  const time_point<_Clock, _Dur2>& __rhs)
1143  { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
1144  /// @}
1145 
1146  /** @{
1147  * Comparisons for time_point
1148  * @relates chrono::time_point
1149  */
1150 
1151  template<typename _Clock, typename _Dur1, typename _Dur2>
1152  constexpr bool
1153  operator==(const time_point<_Clock, _Dur1>& __lhs,
1154  const time_point<_Clock, _Dur2>& __rhs)
1155  { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
1156 
1157 #if __cpp_lib_three_way_comparison
1158  template<typename _Clock, typename _Dur1,
1159  three_way_comparable_with<_Dur1> _Dur2>
1160  constexpr auto
1161  operator<=>(const time_point<_Clock, _Dur1>& __lhs,
1162  const time_point<_Clock, _Dur2>& __rhs)
1163  { return __lhs.time_since_epoch() <=> __rhs.time_since_epoch(); }
1164 #else
1165  template<typename _Clock, typename _Dur1, typename _Dur2>
1166  constexpr bool
1167  operator!=(const time_point<_Clock, _Dur1>& __lhs,
1168  const time_point<_Clock, _Dur2>& __rhs)
1169  { return !(__lhs == __rhs); }
1170 #endif
1171 
1172  template<typename _Clock, typename _Dur1, typename _Dur2>
1173  constexpr bool
1174  operator<(const time_point<_Clock, _Dur1>& __lhs,
1175  const time_point<_Clock, _Dur2>& __rhs)
1176  { return __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
1177 
1178  template<typename _Clock, typename _Dur1, typename _Dur2>
1179  constexpr bool
1180  operator<=(const time_point<_Clock, _Dur1>& __lhs,
1181  const time_point<_Clock, _Dur2>& __rhs)
1182  { return !(__rhs < __lhs); }
1183 
1184  template<typename _Clock, typename _Dur1, typename _Dur2>
1185  constexpr bool
1186  operator>(const time_point<_Clock, _Dur1>& __lhs,
1187  const time_point<_Clock, _Dur2>& __rhs)
1188  { return __rhs < __lhs; }
1189 
1190  template<typename _Clock, typename _Dur1, typename _Dur2>
1191  constexpr bool
1192  operator>=(const time_point<_Clock, _Dur1>& __lhs,
1193  const time_point<_Clock, _Dur2>& __rhs)
1194  { return !(__lhs < __rhs); }
1195 
1196  /// @}
1197  /// @} group chrono
1198 
1199  // Clocks.
1200 
1201  // Why nanosecond resolution as the default?
1202  // Why have std::system_clock always count in the highest
1203  // resolution (ie nanoseconds), even if on some OSes the low 3
1204  // or 9 decimal digits will be always zero? This allows later
1205  // implementations to change the system_clock::now()
1206  // implementation any time to provide better resolution without
1207  // changing function signature or units.
1208 
1209  // To support the (forward) evolution of the library's defined
1210  // clocks, wrap inside inline namespace so that the current
1211  // defintions of system_clock, steady_clock, and
1212  // high_resolution_clock types are uniquely mangled. This way, new
1213  // code can use the latests clocks, while the library can contain
1214  // compatibility definitions for previous versions. At some
1215  // point, when these clocks settle down, the inlined namespaces
1216  // can be removed. XXX GLIBCXX_ABI Deprecated
1217 _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2)
1218 
1219  /**
1220  * @brief System clock.
1221  *
1222  * Time returned represents wall time from the system-wide clock.
1223  * @ingroup chrono
1224  */
1226  {
1227  typedef chrono::nanoseconds duration;
1228  typedef duration::rep rep;
1229  typedef duration::period period;
1231 
1232  static_assert(system_clock::duration::min()
1233  < system_clock::duration::zero(),
1234  "a clock's minimum duration cannot be less than its epoch");
1235 
1236  static constexpr bool is_steady = false;
1237 
1238  static time_point
1239  now() noexcept;
1240 
1241  // Map to C API
1242  static std::time_t
1243  to_time_t(const time_point& __t) noexcept
1244  {
1245  return std::time_t(duration_cast<chrono::seconds>
1246  (__t.time_since_epoch()).count());
1247  }
1248 
1249  static time_point
1250  from_time_t(std::time_t __t) noexcept
1251  {
1254  (__from(chrono::seconds(__t)));
1255  }
1256  };
1257 
1258 
1259  /**
1260  * @brief Monotonic clock
1261  *
1262  * Time returned has the property of only increasing at a uniform rate.
1263  * @ingroup chrono
1264  */
1266  {
1267  typedef chrono::nanoseconds duration;
1268  typedef duration::rep rep;
1269  typedef duration::period period;
1271 
1272  static constexpr bool is_steady = true;
1273 
1274  static time_point
1275  now() noexcept;
1276  };
1277 
1278 
1279  /**
1280  * @brief Highest-resolution clock
1281  *
1282  * This is the clock "with the shortest tick period." Alias to
1283  * std::system_clock until higher-than-nanosecond definitions
1284  * become feasible.
1285  * @ingroup chrono
1286  */
1288 
1289 _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
1290 
1291 #if __cplusplus >= 202002L
1292  /// @addtogroup chrono
1293  /// @{
1294  template<typename _Duration>
1297  using sys_days = sys_time<days>;
1298 
1299  using file_clock = ::std::filesystem::__file_clock;
1300 
1301  template<typename _Duration>
1303 
1304  template<> struct is_clock<system_clock> : true_type { };
1305  template<> struct is_clock<steady_clock> : true_type { };
1306  template<> struct is_clock<file_clock> : true_type { };
1307 
1308  template<> inline constexpr bool is_clock_v<system_clock> = true;
1309  template<> inline constexpr bool is_clock_v<steady_clock> = true;
1310  template<> inline constexpr bool is_clock_v<file_clock> = true;
1311  /// @}
1312 #endif // C++20
1313  } // namespace chrono
1314 
1315 #if __cplusplus >= 201402L
1316 #define __cpp_lib_chrono_udls 201304L
1317 
1318  inline namespace literals
1319  {
1320  /** ISO C++ 2014 namespace for suffixes for duration literals.
1321  *
1322  * These suffixes can be used to create `chrono::duration` values with
1323  * tick periods of hours, minutes, seconds, milliseconds, microseconds
1324  * or nanoseconds. For example, `std::chrono::seconds(5)` can be written
1325  * as `5s` after making the suffix visible in the current scope.
1326  * The suffixes can be made visible by a using-directive or
1327  * using-declaration such as:
1328  * - `using namespace std::chrono_literals;`
1329  * - `using namespace std::literals;`
1330  * - `using namespace std::chrono;`
1331  * - `using namespace std;`
1332  * - `using std::chrono_literals::operator""s;`
1333  *
1334  * The result of these suffixes on an integer literal is one of the
1335  * standard typedefs such as `std::chrono::hours`.
1336  * The result on a floating-point literal is a duration type with the
1337  * specified tick period and an unspecified floating-point representation,
1338  * for example `1.5e2ms` might be equivalent to
1339  * `chrono::duration<long double, chrono::milli>(1.5e2)`.
1340  *
1341  * @since C+14
1342  * @ingroup chrono
1343  */
1344  inline namespace chrono_literals
1345  {
1346  /// @addtogroup chrono
1347  /// @{
1348 
1349 #pragma GCC diagnostic push
1350 #pragma GCC diagnostic ignored "-Wliteral-suffix"
1351  /// @cond undocumented
1352  template<typename _Dur, char... _Digits>
1353  constexpr _Dur __check_overflow()
1354  {
1355  using _Val = __parse_int::_Parse_int<_Digits...>;
1356  constexpr typename _Dur::rep __repval = _Val::value;
1357  static_assert(__repval >= 0 && __repval == _Val::value,
1358  "literal value cannot be represented by duration type");
1359  return _Dur(__repval);
1360  }
1361  /// @endcond
1362 
1363  /// Literal suffix for durations representing non-integer hours
1364  constexpr chrono::duration<long double, ratio<3600,1>>
1365  operator""h(long double __hours)
1366  { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
1367 
1368  /// Literal suffix for durations of type `std::chrono::hours`
1369  template <char... _Digits>
1370  constexpr chrono::hours
1371  operator""h()
1372  { return __check_overflow<chrono::hours, _Digits...>(); }
1373 
1374  /// Literal suffix for durations representing non-integer minutes
1376  operator""min(long double __mins)
1377  { return chrono::duration<long double, ratio<60,1>>{__mins}; }
1378 
1379  /// Literal suffix for durations of type `std::chrono::minutes`
1380  template <char... _Digits>
1381  constexpr chrono::minutes
1382  operator""min()
1383  { return __check_overflow<chrono::minutes, _Digits...>(); }
1384 
1385  /// Literal suffix for durations representing non-integer seconds
1387  operator""s(long double __secs)
1388  { return chrono::duration<long double>{__secs}; }
1389 
1390  /// Literal suffix for durations of type `std::chrono::seconds`
1391  template <char... _Digits>
1392  constexpr chrono::seconds
1393  operator""s()
1394  { return __check_overflow<chrono::seconds, _Digits...>(); }
1395 
1396  /// Literal suffix for durations representing non-integer milliseconds
1398  operator""ms(long double __msecs)
1399  { return chrono::duration<long double, milli>{__msecs}; }
1400 
1401  /// Literal suffix for durations of type `std::chrono::milliseconds`
1402  template <char... _Digits>
1403  constexpr chrono::milliseconds
1404  operator""ms()
1405  { return __check_overflow<chrono::milliseconds, _Digits...>(); }
1406 
1407  /// Literal suffix for durations representing non-integer microseconds
1409  operator""us(long double __usecs)
1410  { return chrono::duration<long double, micro>{__usecs}; }
1411 
1412  /// Literal suffix for durations of type `std::chrono::microseconds`
1413  template <char... _Digits>
1414  constexpr chrono::microseconds
1415  operator""us()
1416  { return __check_overflow<chrono::microseconds, _Digits...>(); }
1417 
1418  /// Literal suffix for durations representing non-integer nanoseconds
1420  operator""ns(long double __nsecs)
1421  { return chrono::duration<long double, nano>{__nsecs}; }
1422 
1423  /// Literal suffix for durations of type `std::chrono::nanoseconds`
1424  template <char... _Digits>
1425  constexpr chrono::nanoseconds
1426  operator""ns()
1427  { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
1428 
1429 #pragma GCC diagnostic pop
1430  /// @}
1431  } // inline namespace chrono_literals
1432  } // inline namespace literals
1433 
1434  namespace chrono
1435  {
1436  using namespace literals::chrono_literals;
1437  } // namespace chrono
1438 #endif // C++14
1439 
1440 #if __cplusplus >= 201703L
1441  namespace filesystem
1442  {
1443  struct __file_clock
1444  {
1445  using duration = chrono::nanoseconds;
1446  using rep = duration::rep;
1447  using period = duration::period;
1448  using time_point = chrono::time_point<__file_clock>;
1449  static constexpr bool is_steady = false;
1450 
1451  static time_point
1452  now() noexcept
1453  { return _S_from_sys(chrono::system_clock::now()); }
1454 
1455 #if __cplusplus > 201703L
1456  template<typename _Dur>
1457  static
1458  chrono::file_time<common_type_t<_Dur, chrono::seconds>>
1459  from_sys(const chrono::sys_time<_Dur>& __t) noexcept
1460  { return _S_from_sys(__t); }
1461 
1462  // For internal use only
1463  template<typename _Dur>
1464  static
1465  chrono::sys_time<common_type_t<_Dur, chrono::seconds>>
1466  to_sys(const chrono::file_time<_Dur>& __t) noexcept
1467  { return _S_to_sys(__t); }
1468 #endif // C++20
1469 
1470  private:
1471  using __sys_clock = chrono::system_clock;
1472 
1473  // This clock's (unspecified) epoch is 2174-01-01 00:00:00 UTC.
1474  // A signed 64-bit duration with nanosecond resolution gives roughly
1475  // +/- 292 years, which covers the 1901-2446 date range for ext4.
1476  static constexpr chrono::seconds _S_epoch_diff{6437664000};
1477 
1478  protected:
1479  // For internal use only
1480  template<typename _Dur>
1481  static
1482  chrono::time_point<__file_clock, common_type_t<_Dur, chrono::seconds>>
1483  _S_from_sys(const chrono::time_point<__sys_clock, _Dur>& __t) noexcept
1484  {
1485  using _CDur = common_type_t<_Dur, chrono::seconds>;
1486  using __file_time = chrono::time_point<__file_clock, _CDur>;
1487  return __file_time{__t.time_since_epoch()} - _S_epoch_diff;
1488  }
1489 
1490  // For internal use only
1491  template<typename _Dur>
1492  static
1493  chrono::time_point<__sys_clock, common_type_t<_Dur, chrono::seconds>>
1494  _S_to_sys(const chrono::time_point<__file_clock, _Dur>& __t) noexcept
1495  {
1496  using _CDur = common_type_t<_Dur, chrono::seconds>;
1497  using __sys_time = chrono::time_point<__sys_clock, _CDur>;
1498  return __sys_time{__t.time_since_epoch()} + _S_epoch_diff;
1499  }
1500  };
1501  } // namespace filesystem
1502 #endif // C++17
1503 
1504 _GLIBCXX_END_NAMESPACE_VERSION
1505 } // namespace std
1506 
1507 #endif // C++11
1508 
1509 #endif //_GLIBCXX_CHRONO_H
integral_constant
Definition: type_traits:62
duration< int64_t > seconds
seconds
Definition: chrono.h:897
constexpr __enable_if_is_duration< _ToDur > floor(const duration< _Rep, _Period > &__d)
Definition: chrono.h:388
Monotonic clock.
Definition: chrono.h:1265
integral_constant< bool, __v > bool_constant
Alias template for compile-time boolean constant types.
Definition: type_traits:98
constexpr time_point< _Clock, typename common_type< _Dur1, duration< _Rep2, _Period2 > >::type > operator+(const time_point< _Clock, _Dur1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:1101
Definition: simd.h:286
static constexpr _Tp max() noexcept
Definition: limits:321
typename common_type< _Tp... >::type common_type_t
Alias template for common_type.
Definition: type_traits:2618
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:106
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:233
constexpr time_point< _Clock, typename common_type< duration< _Rep1, _Period1 >, _Dur2 >::type > operator+(const duration< _Rep1, _Period1 > &__lhs, const time_point< _Clock, _Dur2 > &__rhs)
Adjust a time point forwards by the given duration.
Definition: chrono.h:1115
constexpr duration< __common_rep_t< _Rep1, __disable_if_is_duration< _Rep2 > >, _Period > operator/(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition: chrono.h:756
constexpr duration< __common_rep_t< _Rep1, __disable_if_is_duration< _Rep2 > >, _Period > operator%(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition: chrono.h:779
constexpr __enable_if_t< __is_duration< _ToDur >::value, time_point< _Clock, _ToDur > > time_point_cast(const time_point< _Clock, _Dur > &__t)
Definition: chrono.h:1019
void void_t
A metafunction that always yields void, used for detecting valid types.
Definition: type_traits:2632
System clock.
Definition: chrono.h:1225
duration< int64_t, micro > microseconds
microseconds
Definition: chrono.h:891
constexpr bool operator>=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:869
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:82
constexpr enable_if_t< __and_< __is_duration< _ToDur >, __not_< treat_as_floating_point< typename _ToDur::rep > > >::value, _ToDur > round(const duration< _Rep, _Period > &__d)
Definition: chrono.h:433
duration_values
Definition: chrono.h:495
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition: type_traits:2610
common_type
Definition: type_traits:2245
typename __ratio_divide< _R1, _R2 >::type ratio_divide
ratio_divide
Definition: ratio:387
ISO C++ entities toplevel namespace is std.
Properties of fundamental types.
Definition: limits:312
constexpr duration< __common_rep_t< _Rep2, _Rep1 >, _Period > operator*(const _Rep1 &__s, const duration< _Rep2, _Period > &__d)
Definition: chrono.h:750
chrono::time_point represents a point in time as measured by a clock
Definition: chrono.h:66
constexpr common_type< duration< _Rep1, _Period1 >, duration< _Rep2, _Period2 > >::type operator-(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
The difference between two durations.
Definition: chrono.h:710
chrono::duration represents a distance between two points in time
Definition: chrono.h:62
constexpr __enable_if_is_duration< _ToDur > ceil(const duration< _Rep, _Period > &__d)
Definition: chrono.h:408
duration< int64_t, nano > nanoseconds
nanoseconds
Definition: chrono.h:888
duration< int64_t, milli > milliseconds
milliseconds
Definition: chrono.h:894
constexpr __enable_if_is_duration< _ToDur > duration_cast(const duration< _Rep, _Period > &__d)
Definition: chrono.h:273
duration< int64_t, ratio< 60 > > minutes
minutes
Definition: chrono.h:900
constexpr bool operator>(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:862
constexpr duration< __common_rep_t< _Rep1, _Rep2 >, _Period > operator*(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition: chrono.h:741
is_floating_point
Definition: type_traits:501
duration< int64_t, ratio< 3600 > > hours
hours
Definition: chrono.h:903
constexpr bool operator!=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:847
Provides compile-time rational arithmetic.
Definition: ratio:266
concept same_as
[concept.same], concept same_as
Definition: concepts:63
static constexpr _Tp lowest() noexcept
Definition: limits:327
constexpr bool operator==(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:810
constexpr enable_if_t< numeric_limits< _Rep >::is_signed, duration< _Rep, _Period > > abs(duration< _Rep, _Period > __d)
Definition: chrono.h:459
constexpr common_type< duration< _Rep1, _Period1 >, duration< _Rep2, _Period2 > >::type operator+(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:696