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
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/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:
93  using type = chrono::duration<__cr, typename __r::type>;
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 #endif
280  {
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  }
289  }
290 
291  /** Trait indicating whether to treat a type as a floating-point type.
292  *
293  * The chrono library uses this trait to tell whether a `duration` can
294  * represent fractional values of the given precision, or only integral
295  * values.
296  *
297  * You should specialize this trait for your own numeric types that are
298  * used with `duration` and can represent non-integral values.
299  *
300  * @since C++11
301  */
302  template<typename _Rep>
304  : is_floating_point<_Rep>
305  { };
306 
307 #if __cplusplus > 201402L
308  template <typename _Rep>
309  inline constexpr bool treat_as_floating_point_v =
311 
312  template<>
313  inline constexpr bool treat_as_floating_point_v<int> = false;
314  template<>
315  inline constexpr bool treat_as_floating_point_v<long> = false;
316  template<>
317  inline constexpr bool treat_as_floating_point_v<long long> = false;
318  template<>
319  inline constexpr bool treat_as_floating_point_v<float> = true;
320  template<>
321  inline constexpr bool treat_as_floating_point_v<double> = true;
322  template<>
323  inline constexpr bool treat_as_floating_point_v<long double> = true;
324 #endif // C++17
325 
326 #if __cplusplus > 201703L
327 #if __cpp_lib_concepts
328  template<typename _Tp>
329  inline constexpr bool is_clock_v = false;
330 
331  template<typename _Tp>
332  requires requires {
333  typename _Tp::rep;
334  typename _Tp::period;
335  typename _Tp::duration;
336  typename _Tp::time_point::clock;
337  typename _Tp::time_point::duration;
338  { &_Tp::is_steady } -> same_as<const bool*>;
339  { _Tp::now() } -> same_as<typename _Tp::time_point>;
340  requires same_as<typename _Tp::duration,
341  duration<typename _Tp::rep, typename _Tp::period>>;
342  requires same_as<typename _Tp::time_point::duration,
343  typename _Tp::duration>;
344  }
345  inline constexpr bool is_clock_v<_Tp> = true;
346 #else
347  template<typename _Tp, typename = void>
348  inline constexpr bool is_clock_v = false;
349 
350  template<typename _Tp>
351  inline constexpr bool
352  is_clock_v<_Tp, void_t<typename _Tp::rep, typename _Tp::period,
353  typename _Tp::duration,
354  typename _Tp::time_point::duration,
355  decltype(_Tp::is_steady),
356  decltype(_Tp::now())>>
357  = __and_v<is_same<typename _Tp::duration,
358  duration<typename _Tp::rep, typename _Tp::period>>,
359  is_same<typename _Tp::time_point::duration,
360  typename _Tp::duration>,
361  is_same<decltype(&_Tp::is_steady), const bool*>,
362  is_same<decltype(_Tp::now()), typename _Tp::time_point>>;
363 #endif
364 
365  template<typename _Tp>
366  struct is_clock
367  : bool_constant<is_clock_v<_Tp>>
368  { };
369 #endif // C++20
370 
371 #if __cplusplus >= 201703L
372 # define __cpp_lib_chrono 201611L
373 
374  /** Convert a `duration` to type `ToDur` and round down.
375  *
376  * If the duration cannot be represented exactly in the result type,
377  * returns the closest value that is less than the argument.
378  *
379  * @tparam _ToDur The result type must be a `duration`.
380  * @param __d A duration.
381  * @return The value of `__d` converted to type `_ToDur`.
382  * @since C++17
383  */
384  template<typename _ToDur, typename _Rep, typename _Period>
385  [[nodiscard]] constexpr __enable_if_is_duration<_ToDur>
387  {
388  auto __to = chrono::duration_cast<_ToDur>(__d);
389  if (__to > __d)
390  return __to - _ToDur{1};
391  return __to;
392  }
393 
394  /** Convert a `duration` to type `ToDur` and round up.
395  *
396  * If the duration cannot be represented exactly in the result type,
397  * returns the closest value that is greater than the argument.
398  *
399  * @tparam _ToDur The result type must be a `duration`.
400  * @param __d A duration.
401  * @return The value of `__d` converted to type `_ToDur`.
402  * @since C++17
403  */
404  template<typename _ToDur, typename _Rep, typename _Period>
405  [[nodiscard]] constexpr __enable_if_is_duration<_ToDur>
407  {
408  auto __to = chrono::duration_cast<_ToDur>(__d);
409  if (__to < __d)
410  return __to + _ToDur{1};
411  return __to;
412  }
413 
414  /** Convert a `duration` to type `ToDur` and round to the closest value.
415  *
416  * If the duration cannot be represented exactly in the result type,
417  * returns the closest value, rounding ties to even.
418  *
419  * @tparam _ToDur The result type must be a `duration` with a
420  * non-floating-point `rep` type.
421  * @param __d A duration.
422  * @return The value of `__d` converted to type `_ToDur`.
423  * @since C++17
424  */
425  template <typename _ToDur, typename _Rep, typename _Period>
426  [[nodiscard]] constexpr
427  enable_if_t<
428  __and_<__is_duration<_ToDur>,
429  __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
430  _ToDur>
432  {
433  _ToDur __t0 = chrono::floor<_ToDur>(__d);
434  _ToDur __t1 = __t0 + _ToDur{1};
435  auto __diff0 = __d - __t0;
436  auto __diff1 = __t1 - __d;
437  if (__diff0 == __diff1)
438  {
439  if (__t0.count() & 1)
440  return __t1;
441  return __t0;
442  }
443  else if (__diff0 < __diff1)
444  return __t0;
445  return __t1;
446  }
447 
448  /** The absolute (non-negative) value of a duration.
449  *
450  * @param __d A duration with a signed `rep` type.
451  * @return A duration of the same type as the argument, with value |d|.
452  * @since C++17
453  */
454  template<typename _Rep, typename _Period>
455  [[nodiscard]] constexpr
456  enable_if_t<numeric_limits<_Rep>::is_signed, duration<_Rep, _Period>>
458  {
459  if (__d >= __d.zero())
460  return __d;
461  return -__d;
462  }
463 
464  // Make chrono::ceil<D> also usable as chrono::__detail::ceil<D>.
465  namespace __detail { using chrono::ceil; }
466 
467 #else // ! C++17
468 
469  // We want to use ceil even when compiling for earlier standards versions.
470  // C++11 only allows a single statement in a constexpr function, so we
471  // need to move the comparison into a separate function, __ceil_impl.
472  namespace __detail
473  {
474  template<typename _Tp, typename _Up>
475  constexpr _Tp
476  __ceil_impl(const _Tp& __t, const _Up& __u)
477  {
478  return (__t < __u) ? (__t + _Tp{1}) : __t;
479  }
480 
481  // C++11-friendly version of std::chrono::ceil<D> for internal use.
482  template<typename _ToDur, typename _Rep, typename _Period>
483  constexpr _ToDur
484  ceil(const duration<_Rep, _Period>& __d)
485  {
486  return __detail::__ceil_impl(chrono::duration_cast<_ToDur>(__d), __d);
487  }
488  }
489 #endif // C++17
490 
491  /// duration_values
492  template<typename _Rep>
494  {
495  static constexpr _Rep
496  zero() noexcept
497  { return _Rep(0); }
498 
499  static constexpr _Rep
500  max() noexcept
501  { return numeric_limits<_Rep>::max(); }
502 
503  static constexpr _Rep
504  min() noexcept
505  { return numeric_limits<_Rep>::lowest(); }
506  };
507 
508  /// @cond undocumented
509 
510  template<typename _Tp>
511  struct __is_ratio
513  { };
514 
515  template<intmax_t _Num, intmax_t _Den>
516  struct __is_ratio<ratio<_Num, _Den>>
518  { };
519 
520  /// @endcond
521 
522  template<typename _Rep, typename _Period>
523  class duration
524  {
525  static_assert(!__is_duration<_Rep>::value, "rep cannot be a duration");
526  static_assert(__is_ratio<_Period>::value,
527  "period must be a specialization of ratio");
528  static_assert(_Period::num > 0, "period must be positive");
529 
530  template<typename _Rep2>
532 
533  static constexpr intmax_t
534  _S_gcd(intmax_t __m, intmax_t __n) noexcept
535  {
536  // Duration only allows positive periods so we don't need to
537  // handle negative values here (unlike __static_gcd and std::gcd).
538 #if __cplusplus >= 201402L
539  do
540  {
541  intmax_t __rem = __m % __n;
542  __m = __n;
543  __n = __rem;
544  }
545  while (__n != 0);
546  return __m;
547 #else
548  // C++11 doesn't allow loops in constexpr functions, but this
549  // recursive version can be more expensive to evaluate.
550  return (__n == 0) ? __m : _S_gcd(__n, __m % __n);
551 #endif
552  }
553 
554  // _GLIBCXX_RESOLVE_LIB_DEFECTS
555  // 2094. overflow shouldn't participate in overload resolution
556  // 3090. What is [2094] intended to mean?
557  // This only produces a valid type if no overflow occurs.
558  template<typename _R1, typename _R2,
559  intmax_t __gcd1 = _S_gcd(_R1::num, _R2::num),
560  intmax_t __gcd2 = _S_gcd(_R1::den, _R2::den)>
561  using __divide = ratio<(_R1::num / __gcd1) * (_R2::den / __gcd2),
562  (_R1::den / __gcd2) * (_R2::num / __gcd1)>;
563 
564  // _Period2 is an exact multiple of _Period
565  template<typename _Period2>
566  using __is_harmonic
567  = __bool_constant<__divide<_Period2, _Period>::den == 1>;
568 
569  public:
570 
571  using rep = _Rep;
572  using period = typename _Period::type;
573 
574  // 20.11.5.1 construction / copy / destroy
575  constexpr duration() = default;
576 
577  duration(const duration&) = default;
578 
579  // _GLIBCXX_RESOLVE_LIB_DEFECTS
580  // 3050. Conversion specification problem in chrono::duration
581  template<typename _Rep2, typename = _Require<
582  is_convertible<const _Rep2&, rep>,
583  __or_<__is_float<rep>, __not_<__is_float<_Rep2>>>>>
584  constexpr explicit duration(const _Rep2& __rep)
585  : __r(static_cast<rep>(__rep)) { }
586 
587  template<typename _Rep2, typename _Period2, typename = _Require<
588  is_convertible<const _Rep2&, rep>,
589  __or_<__is_float<rep>,
590  __and_<__is_harmonic<_Period2>,
591  __not_<__is_float<_Rep2>>>>>>
592  constexpr duration(const duration<_Rep2, _Period2>& __d)
593  : __r(duration_cast<duration>(__d).count()) { }
594 
595  ~duration() = default;
596  duration& operator=(const duration&) = default;
597 
598  // 20.11.5.2 observer
599  constexpr rep
600  count() const
601  { return __r; }
602 
603  // 20.11.5.3 arithmetic
604 
606  operator+() const
607  { return duration<typename common_type<rep>::type, period>(__r); }
608 
610  operator-() const
611  { return duration<typename common_type<rep>::type, period>(-__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--()
626  {
627  --__r;
628  return *this;
629  }
630 
631  _GLIBCXX17_CONSTEXPR duration
632  operator--(int)
633  { return duration(__r--); }
634 
635  _GLIBCXX17_CONSTEXPR duration&
636  operator+=(const duration& __d)
637  {
638  __r += __d.count();
639  return *this;
640  }
641 
642  _GLIBCXX17_CONSTEXPR duration&
643  operator-=(const duration& __d)
644  {
645  __r -= __d.count();
646  return *this;
647  }
648 
649  _GLIBCXX17_CONSTEXPR duration&
650  operator*=(const rep& __rhs)
651  {
652  __r *= __rhs;
653  return *this;
654  }
655 
656  _GLIBCXX17_CONSTEXPR duration&
657  operator/=(const rep& __rhs)
658  {
659  __r /= __rhs;
660  return *this;
661  }
662 
663  // DR 934.
664  template<typename _Rep2 = rep>
665  _GLIBCXX17_CONSTEXPR
666  __enable_if_t<!treat_as_floating_point<_Rep2>::value, duration&>
667  operator%=(const rep& __rhs)
668  {
669  __r %= __rhs;
670  return *this;
671  }
672 
673  template<typename _Rep2 = rep>
674  _GLIBCXX17_CONSTEXPR
675  __enable_if_t<!treat_as_floating_point<_Rep2>::value, duration&>
676  operator%=(const duration& __d)
677  {
678  __r %= __d.count();
679  return *this;
680  }
681 
682  // 20.11.5.4 special values
683  static constexpr duration
684  zero() noexcept
685  { return duration(duration_values<rep>::zero()); }
686 
687  static constexpr duration
688  min() noexcept
689  { return duration(duration_values<rep>::min()); }
690 
691  static constexpr duration
692  max() noexcept
693  { return duration(duration_values<rep>::max()); }
694 
695  private:
696  rep __r;
697  };
698 
699  /// @{
700  /// @relates std::chrono::duration
701 
702  /// The sum of two durations.
703  template<typename _Rep1, typename _Period1,
704  typename _Rep2, typename _Period2>
705  constexpr typename common_type<duration<_Rep1, _Period1>,
708  const duration<_Rep2, _Period2>& __rhs)
709  {
710  typedef duration<_Rep1, _Period1> __dur1;
711  typedef duration<_Rep2, _Period2> __dur2;
712  typedef typename common_type<__dur1,__dur2>::type __cd;
713  return __cd(__cd(__lhs).count() + __cd(__rhs).count());
714  }
715 
716  /// The difference between two durations.
717  template<typename _Rep1, typename _Period1,
718  typename _Rep2, typename _Period2>
719  constexpr typename common_type<duration<_Rep1, _Period1>,
722  const duration<_Rep2, _Period2>& __rhs)
723  {
724  typedef duration<_Rep1, _Period1> __dur1;
725  typedef duration<_Rep2, _Period2> __dur2;
726  typedef typename common_type<__dur1,__dur2>::type __cd;
727  return __cd(__cd(__lhs).count() - __cd(__rhs).count());
728  }
729 
730  /// @}
731 
732  /// @cond undocumented
733 
734  // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
735  // is implicitly convertible to it.
736  // _GLIBCXX_RESOLVE_LIB_DEFECTS
737  // 3050. Conversion specification problem in chrono::duration constructor
738  template<typename _Rep1, typename _Rep2,
739  typename _CRep = typename common_type<_Rep1, _Rep2>::type>
740  using __common_rep_t = typename
742 
743  /// @endcond
744 
745  /** @{
746  * Arithmetic operators for chrono::duration
747  * @relates std::chrono::duration
748  */
749 
750  template<typename _Rep1, typename _Period, typename _Rep2>
751  constexpr duration<__common_rep_t<_Rep1, _Rep2>, _Period>
752  operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
753  {
755  __cd;
756  return __cd(__cd(__d).count() * __s);
757  }
758 
759  template<typename _Rep1, typename _Rep2, typename _Period>
760  constexpr duration<__common_rep_t<_Rep2, _Rep1>, _Period>
761  operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
762  { return __d * __s; }
763 
764  template<typename _Rep1, typename _Period, typename _Rep2>
765  constexpr
766  duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
767  operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
768  {
770  __cd;
771  return __cd(__cd(__d).count() / __s);
772  }
773 
774  template<typename _Rep1, typename _Period1,
775  typename _Rep2, typename _Period2>
776  constexpr typename common_type<_Rep1, _Rep2>::type
778  const duration<_Rep2, _Period2>& __rhs)
779  {
780  typedef duration<_Rep1, _Period1> __dur1;
781  typedef duration<_Rep2, _Period2> __dur2;
782  typedef typename common_type<__dur1,__dur2>::type __cd;
783  return __cd(__lhs).count() / __cd(__rhs).count();
784  }
785 
786  // DR 934.
787  template<typename _Rep1, typename _Period, typename _Rep2>
788  constexpr
789  duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
790  operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
791  {
793  __cd;
794  return __cd(__cd(__d).count() % __s);
795  }
796 
797  template<typename _Rep1, typename _Period1,
798  typename _Rep2, typename _Period2>
799  constexpr typename common_type<duration<_Rep1, _Period1>,
800  duration<_Rep2, _Period2>>::type
802  const duration<_Rep2, _Period2>& __rhs)
803  {
804  typedef duration<_Rep1, _Period1> __dur1;
805  typedef duration<_Rep2, _Period2> __dur2;
806  typedef typename common_type<__dur1,__dur2>::type __cd;
807  return __cd(__cd(__lhs).count() % __cd(__rhs).count());
808  }
809  /// @}
810 
811  // comparisons
812 
813  /** @{
814  * Comparisons for chrono::duration
815  * @relates std::chrono::duration
816  */
817 
818  template<typename _Rep1, typename _Period1,
819  typename _Rep2, typename _Period2>
820  constexpr bool
822  const duration<_Rep2, _Period2>& __rhs)
823  {
824  typedef duration<_Rep1, _Period1> __dur1;
825  typedef duration<_Rep2, _Period2> __dur2;
826  typedef typename common_type<__dur1,__dur2>::type __ct;
827  return __ct(__lhs).count() == __ct(__rhs).count();
828  }
829 
830  template<typename _Rep1, typename _Period1,
831  typename _Rep2, typename _Period2>
832  constexpr bool
834  const duration<_Rep2, _Period2>& __rhs)
835  {
836  typedef duration<_Rep1, _Period1> __dur1;
837  typedef duration<_Rep2, _Period2> __dur2;
838  typedef typename common_type<__dur1,__dur2>::type __ct;
839  return __ct(__lhs).count() < __ct(__rhs).count();
840  }
841 
842 #if __cpp_lib_three_way_comparison
843  template<typename _Rep1, typename _Period1,
844  typename _Rep2, typename _Period2>
845  requires three_way_comparable<common_type_t<_Rep1, _Rep2>>
846  constexpr auto
847  operator<=>(const duration<_Rep1, _Period1>& __lhs,
848  const duration<_Rep2, _Period2>& __rhs)
849  {
851  duration<_Rep2, _Period2>>;
852  return __ct(__lhs).count() <=> __ct(__rhs).count();
853  }
854 #else
855  template<typename _Rep1, typename _Period1,
856  typename _Rep2, typename _Period2>
857  constexpr bool
859  const duration<_Rep2, _Period2>& __rhs)
860  { return !(__lhs == __rhs); }
861 #endif
862 
863  template<typename _Rep1, typename _Period1,
864  typename _Rep2, typename _Period2>
865  constexpr bool
867  const duration<_Rep2, _Period2>& __rhs)
868  { return !(__rhs < __lhs); }
869 
870  template<typename _Rep1, typename _Period1,
871  typename _Rep2, typename _Period2>
872  constexpr bool
874  const duration<_Rep2, _Period2>& __rhs)
875  { return __rhs < __lhs; }
876 
877  template<typename _Rep1, typename _Period1,
878  typename _Rep2, typename _Period2>
879  constexpr bool
881  const duration<_Rep2, _Period2>& __rhs)
882  { return !(__lhs < __rhs); }
883 
884  /// @}
885 
886  /// @cond undocumented
887 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
888 # define _GLIBCXX_CHRONO_INT64_T int64_t
889 #elif defined __INT64_TYPE__
890 # define _GLIBCXX_CHRONO_INT64_T __INT64_TYPE__
891 #else
893  "Representation type for nanoseconds must have at least 64 bits");
894 # define _GLIBCXX_CHRONO_INT64_T long long
895 #endif
896  /// @endcond
897 
898  /// nanoseconds
900 
901  /// microseconds
903 
904  /// milliseconds
906 
907  /// seconds
909 
910  /// minutes
912 
913  /// hours
915 
916 #if __cplusplus > 201703L
917  /// days
919 
920  /// weeks
922 
923  /// years
925 
926  /// months
928 #endif // C++20
929 
930 #undef _GLIBCXX_CHRONO_INT64_T
931 
932  template<typename _Clock, typename _Dur>
934  {
935  static_assert(__is_duration<_Dur>::value,
936  "duration must be a specialization of std::chrono::duration");
937 
938  public:
939  typedef _Clock clock;
940  typedef _Dur duration;
941  typedef typename duration::rep rep;
942  typedef typename duration::period period;
943 
944  constexpr time_point() : __d(duration::zero())
945  { }
946 
947  constexpr explicit time_point(const duration& __dur)
948  : __d(__dur)
949  { }
950 
951  // conversions
952  template<typename _Dur2,
953  typename = _Require<is_convertible<_Dur2, _Dur>>>
954  constexpr time_point(const time_point<clock, _Dur2>& __t)
955  : __d(__t.time_since_epoch())
956  { }
957 
958  // observer
959  constexpr duration
960  time_since_epoch() const
961  { return __d; }
962 
963 #if __cplusplus > 201703L
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 
975  constexpr time_point&
976  operator--()
977  {
978  --__d;
979  return *this;
980  }
981 
982  constexpr time_point
983  operator--(int)
984  { return time_point{__d--}; }
985 #endif
986 
987  // arithmetic
988  _GLIBCXX17_CONSTEXPR time_point&
989  operator+=(const duration& __dur)
990  {
991  __d += __dur;
992  return *this;
993  }
994 
995  _GLIBCXX17_CONSTEXPR time_point&
996  operator-=(const duration& __dur)
997  {
998  __d -= __dur;
999  return *this;
1000  }
1001 
1002  // special values
1003  static constexpr time_point
1004  min() noexcept
1005  { return time_point(duration::min()); }
1006 
1007  static constexpr time_point
1008  max() noexcept
1009  { return time_point(duration::max()); }
1010 
1011  private:
1012  duration __d;
1013  };
1014 
1015  /** Convert a `time_point` to use `duration` type `ToDur`.
1016  *
1017  * The result is the same time point as measured by the same clock, but
1018  * using the specified `duration` to represent the time.
1019  * If the time point cannot be represented accurately in the result type,
1020  * returns the result of integer truncation (i.e., rounded towards zero).
1021  *
1022  * @tparam _ToDur The `duration` type to use for the result.
1023  * @param __t A time point.
1024  * @return The value of `__t` converted to use type `_ToDur`.
1025  * @since C++11
1026  */
1027  template<typename _ToDur, typename _Clock, typename _Dur>
1028  _GLIBCXX_NODISCARD constexpr
1029  __enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
1031  {
1032  typedef time_point<_Clock, _ToDur> __time_point;
1033  return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
1034  }
1035 
1036 #if __cplusplus > 201402L
1037  /** Convert a `time_point` to type `ToDur` and round down.
1038  *
1039  * The result is the same time point as measured by the same clock, but
1040  * using the specified `duration` to represent the time.
1041  * If the time point cannot be represented exactly in the result type,
1042  * returns the closest value that is less than the argument.
1043  *
1044  * @tparam _ToDur The `duration` type to use for the result.
1045  * @param __t A time point.
1046  * @return The value of `__d` converted to type `_ToDur`.
1047  * @since C++17
1048  */
1049  template<typename _ToDur, typename _Clock, typename _Dur>
1050  [[nodiscard]] constexpr
1051  enable_if_t<__is_duration_v<_ToDur>, time_point<_Clock, _ToDur>>
1053  {
1055  chrono::floor<_ToDur>(__tp.time_since_epoch())};
1056  }
1057 
1058  /** Convert a `time_point` to type `ToDur` and round up.
1059  *
1060  * The result is the same time point as measured by the same clock, but
1061  * using the specified `duration` to represent the time.
1062  * If the time point cannot be represented exactly in the result type,
1063  * returns the closest value that is greater than the argument.
1064  *
1065  * @tparam _ToDur The `duration` type to use for the result.
1066  * @param __t A time point.
1067  * @return The value of `__d` converted to type `_ToDur`.
1068  * @since C++17
1069  */
1070  template<typename _ToDur, typename _Clock, typename _Dur>
1071  [[nodiscard]] constexpr
1072  enable_if_t<__is_duration_v<_ToDur>, time_point<_Clock, _ToDur>>
1074  {
1076  chrono::ceil<_ToDur>(__tp.time_since_epoch())};
1077  }
1078 
1079  /** Convert a `time_point` to type `ToDur` and round to the closest value.
1080  *
1081  * The result is the same time point as measured by the same clock, but
1082  * using the specified `duration` to represent the time.
1083  * If the time point cannot be represented exactly in the result type,
1084  * returns the closest value, rounding ties to even.
1085  *
1086  * @tparam _ToDur The `duration` type to use for the result,
1087  * which must have a non-floating-point `rep` type.
1088  * @param __t A time point.
1089  * @return The value of `__d` converted to type `_ToDur`.
1090  * @since C++17
1091  */
1092  template<typename _ToDur, typename _Clock, typename _Dur>
1093  [[nodiscard]] constexpr
1095  && !treat_as_floating_point_v<typename _ToDur::rep>,
1096  time_point<_Clock, _ToDur>>
1098  {
1100  chrono::round<_ToDur>(__tp.time_since_epoch())};
1101  }
1102 #endif // C++17
1103 
1104  /// @{
1105  /// @relates time_point
1106 
1107  /// Adjust a time point forwards by the given duration.
1108  template<typename _Clock, typename _Dur1,
1109  typename _Rep2, typename _Period2>
1110  constexpr time_point<_Clock,
1113  const duration<_Rep2, _Period2>& __rhs)
1114  {
1115  typedef duration<_Rep2, _Period2> __dur2;
1116  typedef typename common_type<_Dur1,__dur2>::type __ct;
1117  typedef time_point<_Clock, __ct> __time_point;
1118  return __time_point(__lhs.time_since_epoch() + __rhs);
1119  }
1120 
1121  /// Adjust a time point forwards by the given duration.
1122  template<typename _Rep1, typename _Period1,
1123  typename _Clock, typename _Dur2>
1124  constexpr time_point<_Clock,
1125  typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
1127  const time_point<_Clock, _Dur2>& __rhs)
1128  {
1129  typedef duration<_Rep1, _Period1> __dur1;
1130  typedef typename common_type<__dur1,_Dur2>::type __ct;
1131  typedef time_point<_Clock, __ct> __time_point;
1132  return __time_point(__rhs.time_since_epoch() + __lhs);
1133  }
1134 
1135  /// Adjust a time point backwards by the given duration.
1136  template<typename _Clock, typename _Dur1,
1137  typename _Rep2, typename _Period2>
1138  constexpr time_point<_Clock,
1141  const duration<_Rep2, _Period2>& __rhs)
1142  {
1143  typedef duration<_Rep2, _Period2> __dur2;
1144  typedef typename common_type<_Dur1,__dur2>::type __ct;
1145  typedef time_point<_Clock, __ct> __time_point;
1146  return __time_point(__lhs.time_since_epoch() -__rhs);
1147  }
1148 
1149  /// The difference between two time points (as a duration)
1150  template<typename _Clock, typename _Dur1, typename _Dur2>
1151  constexpr typename common_type<_Dur1, _Dur2>::type
1153  const time_point<_Clock, _Dur2>& __rhs)
1154  { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
1155  /// @}
1156 
1157  /** @{
1158  * Comparisons for time_point
1159  * @relates chrono::time_point
1160  */
1161 
1162  template<typename _Clock, typename _Dur1, typename _Dur2>
1163  constexpr bool
1164  operator==(const time_point<_Clock, _Dur1>& __lhs,
1165  const time_point<_Clock, _Dur2>& __rhs)
1166  { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
1167 
1168 #if __cpp_lib_three_way_comparison
1169  template<typename _Clock, typename _Dur1,
1170  three_way_comparable_with<_Dur1> _Dur2>
1171  constexpr auto
1172  operator<=>(const time_point<_Clock, _Dur1>& __lhs,
1173  const time_point<_Clock, _Dur2>& __rhs)
1174  { return __lhs.time_since_epoch() <=> __rhs.time_since_epoch(); }
1175 #else
1176  template<typename _Clock, typename _Dur1, typename _Dur2>
1177  constexpr bool
1178  operator!=(const time_point<_Clock, _Dur1>& __lhs,
1179  const time_point<_Clock, _Dur2>& __rhs)
1180  { return !(__lhs == __rhs); }
1181 #endif
1182 
1183  template<typename _Clock, typename _Dur1, typename _Dur2>
1184  constexpr bool
1185  operator<(const time_point<_Clock, _Dur1>& __lhs,
1186  const time_point<_Clock, _Dur2>& __rhs)
1187  { return __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
1188 
1189  template<typename _Clock, typename _Dur1, typename _Dur2>
1190  constexpr bool
1191  operator<=(const time_point<_Clock, _Dur1>& __lhs,
1192  const time_point<_Clock, _Dur2>& __rhs)
1193  { return !(__rhs < __lhs); }
1194 
1195  template<typename _Clock, typename _Dur1, typename _Dur2>
1196  constexpr bool
1197  operator>(const time_point<_Clock, _Dur1>& __lhs,
1198  const time_point<_Clock, _Dur2>& __rhs)
1199  { return __rhs < __lhs; }
1200 
1201  template<typename _Clock, typename _Dur1, typename _Dur2>
1202  constexpr bool
1203  operator>=(const time_point<_Clock, _Dur1>& __lhs,
1204  const time_point<_Clock, _Dur2>& __rhs)
1205  { return !(__lhs < __rhs); }
1206 
1207  /// @}
1208  /// @} group chrono
1209 
1210  // Clocks.
1211 
1212  // Why nanosecond resolution as the default?
1213  // Why have std::system_clock always count in the highest
1214  // resolution (ie nanoseconds), even if on some OSes the low 3
1215  // or 9 decimal digits will be always zero? This allows later
1216  // implementations to change the system_clock::now()
1217  // implementation any time to provide better resolution without
1218  // changing function signature or units.
1219 
1220  // To support the (forward) evolution of the library's defined
1221  // clocks, wrap inside inline namespace so that the current
1222  // defintions of system_clock, steady_clock, and
1223  // high_resolution_clock types are uniquely mangled. This way, new
1224  // code can use the latests clocks, while the library can contain
1225  // compatibility definitions for previous versions. At some
1226  // point, when these clocks settle down, the inlined namespaces
1227  // can be removed. XXX GLIBCXX_ABI Deprecated
1228 _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2)
1229 
1230  /**
1231  * @brief System clock.
1232  *
1233  * Time returned represents wall time from the system-wide clock.
1234  * @ingroup chrono
1235  */
1237  {
1238  typedef chrono::nanoseconds duration;
1239  typedef duration::rep rep;
1240  typedef duration::period period;
1242 
1243  static_assert(system_clock::duration::min()
1244  < system_clock::duration::zero(),
1245  "a clock's minimum duration cannot be less than its epoch");
1246 
1247  static constexpr bool is_steady = false;
1248 
1249  static time_point
1250  now() noexcept;
1251 
1252  // Map to C API
1253  static std::time_t
1254  to_time_t(const time_point& __t) noexcept
1255  {
1256  return std::time_t(duration_cast<chrono::seconds>
1257  (__t.time_since_epoch()).count());
1258  }
1259 
1260  static time_point
1261  from_time_t(std::time_t __t) noexcept
1262  {
1264  return time_point_cast<system_clock::duration>
1265  (__from(chrono::seconds(__t)));
1266  }
1267  };
1268 
1269 
1270  /**
1271  * @brief Monotonic clock
1272  *
1273  * Time returned has the property of only increasing at a uniform rate.
1274  * @ingroup chrono
1275  */
1277  {
1278  typedef chrono::nanoseconds duration;
1279  typedef duration::rep rep;
1280  typedef duration::period period;
1282 
1283  static constexpr bool is_steady = true;
1284 
1285  static time_point
1286  now() noexcept;
1287  };
1288 
1289 
1290  /**
1291  * @brief Highest-resolution clock
1292  *
1293  * This is the clock "with the shortest tick period." Alias to
1294  * std::system_clock until higher-than-nanosecond definitions
1295  * become feasible.
1296  * @ingroup chrono
1297  */
1299 
1300 _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
1301 
1302 #if __cplusplus >= 202002L
1303  /// @addtogroup chrono
1304  /// @{
1305  template<typename _Duration>
1308  using sys_days = sys_time<days>;
1309 
1310  using file_clock = ::std::filesystem::__file_clock;
1311 
1312  template<typename _Duration>
1314 
1315  template<> struct is_clock<system_clock> : true_type { };
1316  template<> struct is_clock<steady_clock> : true_type { };
1317  template<> struct is_clock<file_clock> : true_type { };
1318 
1319  template<> inline constexpr bool is_clock_v<system_clock> = true;
1320  template<> inline constexpr bool is_clock_v<steady_clock> = true;
1321  template<> inline constexpr bool is_clock_v<file_clock> = true;
1322  /// @}
1323 #endif // C++20
1324  } // namespace chrono
1325 
1326 #if __cplusplus >= 201402L
1327 #define __cpp_lib_chrono_udls 201304L
1328 
1329  inline namespace literals
1330  {
1331  /** ISO C++ 2014 namespace for suffixes for duration literals.
1332  *
1333  * These suffixes can be used to create `chrono::duration` values with
1334  * tick periods of hours, minutes, seconds, milliseconds, microseconds
1335  * or nanoseconds. For example, `std::chrono::seconds(5)` can be written
1336  * as `5s` after making the suffix visible in the current scope.
1337  * The suffixes can be made visible by a using-directive or
1338  * using-declaration such as:
1339  * - `using namespace std::chrono_literals;`
1340  * - `using namespace std::literals;`
1341  * - `using namespace std::chrono;`
1342  * - `using namespace std;`
1343  * - `using std::chrono_literals::operator""s;`
1344  *
1345  * The result of these suffixes on an integer literal is one of the
1346  * standard typedefs such as `std::chrono::hours`.
1347  * The result on a floating-point literal is a duration type with the
1348  * specified tick period and an unspecified floating-point representation,
1349  * for example `1.5e2ms` might be equivalent to
1350  * `chrono::duration<long double, chrono::milli>(1.5e2)`.
1351  *
1352  * @since C+14
1353  * @ingroup chrono
1354  */
1355  inline namespace chrono_literals
1356  {
1357  /// @addtogroup chrono
1358  /// @{
1359 
1360 #pragma GCC diagnostic push
1361 #pragma GCC diagnostic ignored "-Wliteral-suffix"
1362  /// @cond undocumented
1363  template<typename _Dur, char... _Digits>
1364  constexpr _Dur __check_overflow()
1365  {
1366  using _Val = __parse_int::_Parse_int<_Digits...>;
1367  constexpr typename _Dur::rep __repval = _Val::value;
1368  static_assert(__repval >= 0 && __repval == _Val::value,
1369  "literal value cannot be represented by duration type");
1370  return _Dur(__repval);
1371  }
1372  /// @endcond
1373 
1374  /// Literal suffix for durations representing non-integer hours
1375  constexpr chrono::duration<long double, ratio<3600,1>>
1376  operator""h(long double __hours)
1377  { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
1378 
1379  /// Literal suffix for durations of type `std::chrono::hours`
1380  template <char... _Digits>
1381  constexpr chrono::hours
1382  operator""h()
1383  { return __check_overflow<chrono::hours, _Digits...>(); }
1384 
1385  /// Literal suffix for durations representing non-integer minutes
1387  operator""min(long double __mins)
1388  { return chrono::duration<long double, ratio<60,1>>{__mins}; }
1389 
1390  /// Literal suffix for durations of type `std::chrono::minutes`
1391  template <char... _Digits>
1392  constexpr chrono::minutes
1393  operator""min()
1394  { return __check_overflow<chrono::minutes, _Digits...>(); }
1395 
1396  /// Literal suffix for durations representing non-integer seconds
1398  operator""s(long double __secs)
1399  { return chrono::duration<long double>{__secs}; }
1400 
1401  /// Literal suffix for durations of type `std::chrono::seconds`
1402  template <char... _Digits>
1403  constexpr chrono::seconds
1404  operator""s()
1405  { return __check_overflow<chrono::seconds, _Digits...>(); }
1406 
1407  /// Literal suffix for durations representing non-integer milliseconds
1409  operator""ms(long double __msecs)
1410  { return chrono::duration<long double, milli>{__msecs}; }
1411 
1412  /// Literal suffix for durations of type `std::chrono::milliseconds`
1413  template <char... _Digits>
1414  constexpr chrono::milliseconds
1415  operator""ms()
1416  { return __check_overflow<chrono::milliseconds, _Digits...>(); }
1417 
1418  /// Literal suffix for durations representing non-integer microseconds
1420  operator""us(long double __usecs)
1421  { return chrono::duration<long double, micro>{__usecs}; }
1422 
1423  /// Literal suffix for durations of type `std::chrono::microseconds`
1424  template <char... _Digits>
1425  constexpr chrono::microseconds
1426  operator""us()
1427  { return __check_overflow<chrono::microseconds, _Digits...>(); }
1428 
1429  /// Literal suffix for durations representing non-integer nanoseconds
1431  operator""ns(long double __nsecs)
1432  { return chrono::duration<long double, nano>{__nsecs}; }
1433 
1434  /// Literal suffix for durations of type `std::chrono::nanoseconds`
1435  template <char... _Digits>
1436  constexpr chrono::nanoseconds
1437  operator""ns()
1438  { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
1439 
1440 #pragma GCC diagnostic pop
1441  /// @}
1442  } // inline namespace chrono_literals
1443  } // inline namespace literals
1444 
1445  namespace chrono
1446  {
1447  using namespace literals::chrono_literals;
1448  } // namespace chrono
1449 #endif // C++14
1450 
1451 #if __cplusplus >= 201703L
1452  namespace filesystem
1453  {
1454  struct __file_clock
1455  {
1456  using duration = chrono::nanoseconds;
1457  using rep = duration::rep;
1458  using period = duration::period;
1459  using time_point = chrono::time_point<__file_clock>;
1460  static constexpr bool is_steady = false;
1461 
1462  static time_point
1463  now() noexcept
1464  { return _S_from_sys(chrono::system_clock::now()); }
1465 
1466 #if __cplusplus > 201703L
1467  template<typename _Dur>
1468  static
1469  chrono::file_time<_Dur>
1470  from_sys(const chrono::sys_time<_Dur>& __t) noexcept
1471  { return _S_from_sys(__t); }
1472 
1473  // For internal use only
1474  template<typename _Dur>
1475  static
1476  chrono::sys_time<_Dur>
1477  to_sys(const chrono::file_time<_Dur>& __t) noexcept
1478  { return _S_to_sys(__t); }
1479 #endif // C++20
1480 
1481  private:
1482  using __sys_clock = chrono::system_clock;
1483 
1484  // This clock's (unspecified) epoch is 2174-01-01 00:00:00 UTC.
1485  // A signed 64-bit duration with nanosecond resolution gives roughly
1486  // +/- 292 years, which covers the 1901-2446 date range for ext4.
1487  static constexpr chrono::seconds _S_epoch_diff{6437664000};
1488 
1489  protected:
1490  // For internal use only
1491  template<typename _Dur>
1492  static
1493  chrono::time_point<__file_clock, _Dur>
1494  _S_from_sys(const chrono::time_point<__sys_clock, _Dur>& __t) noexcept
1495  {
1496  using __file_time = chrono::time_point<__file_clock, _Dur>;
1497  return __file_time{__t.time_since_epoch()} - _S_epoch_diff;
1498  }
1499 
1500  // For internal use only
1501  template<typename _Dur>
1502  static
1503  chrono::time_point<__sys_clock, _Dur>
1504  _S_to_sys(const chrono::time_point<__file_clock, _Dur>& __t) noexcept
1505  {
1506  using __sys_time = chrono::time_point<__sys_clock, _Dur>;
1507  return __sys_time{__t.time_since_epoch()} + _S_epoch_diff;
1508  }
1509  };
1510  } // namespace filesystem
1511 #endif // C++17
1512 
1513 _GLIBCXX_END_NAMESPACE_VERSION
1514 } // namespace std
1515 
1516 #endif // C++11
1517 
1518 #endif //_GLIBCXX_CHRONO_H
constexpr duration< __common_rep_t< _Rep1, __disable_if_is_duration< _Rep2 > >, _Period > operator%(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition: chrono.h:790
constexpr bool operator==(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:821
duration< int64_t > seconds
seconds
Definition: chrono.h:908
constexpr enable_if_t< numeric_limits< _Rep >::is_signed, duration< _Rep, _Period > > abs(duration< _Rep, _Period > __d)
Definition: chrono.h:457
constexpr bool operator<=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:866
duration< int64_t, ratio< 3600 > > hours
hours
Definition: chrono.h:914
duration< int64_t, milli > milliseconds
milliseconds
Definition: chrono.h:905
constexpr __enable_if_is_duration< _ToDur > duration_cast(const duration< _Rep, _Period > &__d)
Definition: chrono.h:273
duration< int64_t, micro > microseconds
microseconds
Definition: chrono.h:902
constexpr bool operator>=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:880
constexpr bool operator!=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:858
duration< int64_t, nano > nanoseconds
nanoseconds
Definition: chrono.h:899
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:1126
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:1112
constexpr duration< __common_rep_t< _Rep2, _Rep1 >, _Period > operator*(const _Rep1 &__s, const duration< _Rep2, _Period > &__d)
Definition: chrono.h:761
constexpr __enable_if_is_duration< _ToDur > floor(const duration< _Rep, _Period > &__d)
Definition: chrono.h:386
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:721
duration< int64_t, ratio< 60 > > minutes
minutes
Definition: chrono.h:911
constexpr __enable_if_is_duration< _ToDur > ceil(const duration< _Rep, _Period > &__d)
Definition: chrono.h:406
constexpr common_type< duration< _Rep1, _Period1 >, duration< _Rep2, _Period2 > >::type operator+(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:707
constexpr bool operator<(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:833
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:431
constexpr duration< __common_rep_t< _Rep1, __disable_if_is_duration< _Rep2 > >, _Period > operator/(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition: chrono.h:767
constexpr bool operator>(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition: chrono.h:873
constexpr duration< __common_rep_t< _Rep1, _Rep2 >, _Period > operator*(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition: chrono.h:752
constexpr __enable_if_t< __is_duration< _ToDur >::value, time_point< _Clock, _ToDur > > time_point_cast(const time_point< _Clock, _Dur > &__t)
Definition: chrono.h:1030
typename __ratio_divide< _R1, _R2 >::type ratio_divide
ratio_divide
Definition: ratio:353
integral_constant< bool, __v > bool_constant
Alias template for compile-time boolean constant types.
Definition: type_traits:98
void void_t
A metafunction that always yields void, used for detecting valid types.
Definition: type_traits:2632
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:82
typename common_type< _Tp... >::type common_type_t
Alias template for common_type.
Definition: type_traits:2618
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition: type_traits:2610
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:233
ISO C++ entities toplevel namespace is std.
concept same_as
[concept.same], concept same_as
Definition: concepts:63
Properties of fundamental types.
Definition: limits:313
static constexpr _Tp max() noexcept
Definition: limits:321
static constexpr _Tp lowest() noexcept
Definition: limits:327
Provides compile-time rational arithmetic.
Definition: ratio:267
integral_constant
Definition: type_traits:63
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:107
is_floating_point
Definition: type_traits:503
common_type
Definition: type_traits:2245
chrono::duration represents a distance between two points in time
Definition: chrono.h:524
chrono::time_point represents a point in time as measured by a clock
Definition: chrono.h:934
duration_values
Definition: chrono.h:494
Monotonic clock.
Definition: chrono.h:1277