libstdc++: chrono.h Source File

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chrono.h
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1// chrono::duration and chrono::time_point -*- C++ -*-
2
3// Copyright (C) 2008-2026 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#ifdef _GLIBCXX_SYSHDR
34#pragma GCC system_header
35#endif
36
37#if __cplusplus >= 201103L
38
39#include <ratio>
40#include <type_traits>
41#include <limits>
42#if _GLIBCXX_HOSTED
43# include <ctime>
44#endif
45#include <bits/parse_numbers.h> // for literals support.
46#if __cplusplus >= 202002L
47# include <concepts>
48# include <compare>
49#endif
50
51#include <bits/version.h>
52
53namespace std _GLIBCXX_VISIBILITY(default)
54{
55_GLIBCXX_BEGIN_NAMESPACE_VERSION
56
57#if __cplusplus >= 201703L && _GLIBCXX_HOSTED
58 namespace filesystem { struct __file_clock; };
59#endif
60
61 namespace chrono
62 {
63 /// @addtogroup chrono
64 /// @{
65
66 /// `chrono::duration` represents a distance between two points in time
67 template<typename _Rep, typename _Period = ratio<1>>
68 class duration;
69
70 /// `chrono::time_point` represents a point in time as measured by a clock
71 template<typename _Clock, typename _Dur = typename _Clock::duration>
72 class time_point;
73 /// @}
74 }
75
76 /// @addtogroup chrono
77 /// @{
78
79 // 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
80
81 /// @cond undocumented
82
83 template<typename _CT, typename _Period1, typename _Period2, typename = void>
84 struct __duration_common_type
85 { };
86
87 template<typename _CT, typename _Period1, typename _Period2>
88 struct __duration_common_type<_CT, _Period1, _Period2,
89 __void_t<typename _CT::type>>
90 {
91 private:
92 using __gcd_num = __static_gcd<_Period1::num, _Period2::num>;
93 using __gcd_den = __static_gcd<_Period1::den, _Period2::den>;
94 using __cr = typename _CT::type;
95 using __r = ratio<__gcd_num::value,
96 (_Period1::den / __gcd_den::value) * _Period2::den>;
97
98 public:
99 using type = chrono::duration<__cr, typename __r::type>;
100 };
101
102 /// @endcond
103
104 /// @{
105 /// @relates chrono::duration
106
107 /// Specialization of common_type for chrono::duration types.
108 template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
109 struct common_type<chrono::duration<_Rep1, _Period1>,
110 chrono::duration<_Rep2, _Period2>>
111 : __duration_common_type<common_type<_Rep1, _Rep2>,
112 typename _Period1::type,
113 typename _Period2::type>
114 { };
115
116 /// Specialization of common_type for two identical chrono::duration types.
117 template<typename _Rep, typename _Period>
118 struct common_type<chrono::duration<_Rep, _Period>,
119 chrono::duration<_Rep, _Period>>
120 {
121 using type = chrono::duration<typename common_type<_Rep>::type,
122 typename _Period::type>;
123 };
124
125 /// Specialization of common_type for one chrono::duration type.
126 template<typename _Rep, typename _Period>
127 struct common_type<chrono::duration<_Rep, _Period>>
128 {
129 using type = chrono::duration<typename common_type<_Rep>::type,
130 typename _Period::type>;
131 };
132 /// @}
133
134 // 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
135
136 /// @cond undocumented
137
138 template<typename _CT, typename _Clock, typename = void>
139 struct __timepoint_common_type
140 { };
141
142 template<typename _CT, typename _Clock>
143 struct __timepoint_common_type<_CT, _Clock, __void_t<typename _CT::type>>
144 {
145 using type = chrono::time_point<_Clock, typename _CT::type>;
146 };
147
148 /// @endcond
149
150 /// @{
151 /// @relates chrono::time_point
152
153 /// Specialization of common_type for chrono::time_point types.
154 template<typename _Clock, typename _Duration1, typename _Duration2>
155 struct common_type<chrono::time_point<_Clock, _Duration1>,
156 chrono::time_point<_Clock, _Duration2>>
157 : __timepoint_common_type<common_type<_Duration1, _Duration2>, _Clock>
158 { };
159
160 /// Specialization of common_type for two identical chrono::time_point types.
161 template<typename _Clock, typename _Duration>
162 struct common_type<chrono::time_point<_Clock, _Duration>,
163 chrono::time_point<_Clock, _Duration>>
164 { using type = chrono::time_point<_Clock, _Duration>; };
165
166 /// Specialization of common_type for one chrono::time_point type.
167 template<typename _Clock, typename _Duration>
168 struct common_type<chrono::time_point<_Clock, _Duration>>
169 { using type = chrono::time_point<_Clock, _Duration>; };
170 /// @}
171
172 /// @} group chrono
173
174 namespace chrono
175 {
176 /// @addtogroup chrono
177 /// @{
178
179 /// @cond undocumented
180
181 // Primary template for duration_cast impl.
182 template<typename _ToDur, typename _CF, typename _CR,
183 bool _NumIsOne = false, bool _DenIsOne = false>
184 struct __duration_cast_impl
185 {
186 template<typename _Rep, typename _Period>
187 static constexpr _ToDur
188 __cast(const duration<_Rep, _Period>& __d)
189 {
190 typedef typename _ToDur::rep __to_rep;
191 return _ToDur(static_cast<__to_rep>(static_cast<_CR>(__d.count())
192 * static_cast<_CR>(_CF::num)
193 / static_cast<_CR>(_CF::den)));
194 }
195 };
196
197 template<typename _ToDur, typename _CF, typename _CR>
198 struct __duration_cast_impl<_ToDur, _CF, _CR, true, true>
199 {
200 template<typename _Rep, typename _Period>
201 static constexpr _ToDur
202 __cast(const duration<_Rep, _Period>& __d)
203 {
204 typedef typename _ToDur::rep __to_rep;
205 return _ToDur(static_cast<__to_rep>(__d.count()));
206 }
207 };
208
209 template<typename _ToDur, typename _CF, typename _CR>
210 struct __duration_cast_impl<_ToDur, _CF, _CR, true, false>
211 {
212 template<typename _Rep, typename _Period>
213 static constexpr _ToDur
214 __cast(const duration<_Rep, _Period>& __d)
215 {
216 typedef typename _ToDur::rep __to_rep;
217 return _ToDur(static_cast<__to_rep>(
218 static_cast<_CR>(__d.count()) / static_cast<_CR>(_CF::den)));
219 }
220 };
221
222 template<typename _ToDur, typename _CF, typename _CR>
223 struct __duration_cast_impl<_ToDur, _CF, _CR, false, true>
224 {
225 template<typename _Rep, typename _Period>
226 static constexpr _ToDur
227 __cast(const duration<_Rep, _Period>& __d)
228 {
229 typedef typename _ToDur::rep __to_rep;
230 return _ToDur(static_cast<__to_rep>(
231 static_cast<_CR>(__d.count()) * static_cast<_CR>(_CF::num)));
232 }
233 };
234
235 template<typename _Tp>
236 struct __is_duration
237 : std::false_type
238 { };
239
240 template<typename _Rep, typename _Period>
241 struct __is_duration<duration<_Rep, _Period>>
242 : std::true_type
243 { };
244
245 template<typename _Tp>
246 using __enable_if_is_duration
247 = typename enable_if<__is_duration<_Tp>::value, _Tp>::type;
248
249 template<typename _Tp>
250 using __disable_if_is_duration
251 = typename enable_if<!__is_duration<_Tp>::value, _Tp>::type;
252
253#if __cplusplus >= 201703L
254 template<typename _Tp>
255 inline constexpr bool __is_duration_v = false;
256 template<typename _Rep, typename _Period>
257 inline constexpr bool __is_duration_v<duration<_Rep, _Period>> = true;
258 template<typename _Tp>
259 inline constexpr bool __is_time_point_v = false;
260 template<typename _Clock, typename _Dur>
261 inline constexpr bool __is_time_point_v<time_point<_Clock, _Dur>> = true;
262#endif
263
264 /// @endcond
265
266 /** Convert a `duration` to type `ToDur`.
267 *
268 * If the duration cannot be represented accurately in the result type,
269 * returns the result of integer truncation (i.e., rounded towards zero).
270 *
271 * @tparam _ToDur The result type must be a `duration`.
272 * @param __d A duration.
273 * @return The value of `__d` converted to type `_ToDur`.
274 * @since C++11
275 */
276 template<typename _ToDur, typename _Rep, typename _Period>
277 _GLIBCXX_NODISCARD
278 constexpr __enable_if_is_duration<_ToDur>
279 duration_cast(const duration<_Rep, _Period>& __d)
280 {
281#if __cpp_inline_variables && __cpp_if_constexpr
282 if constexpr (is_same_v<_ToDur, duration<_Rep, _Period>>)
283 return __d;
284 else
285 {
286#endif
287 using __to_period = typename _ToDur::period;
288 using __to_rep = typename _ToDur::rep;
289 using __cf = ratio_divide<_Period, __to_period>;
290 using __cr = typename common_type<__to_rep, _Rep, intmax_t>::type;
291 using __dc = __duration_cast_impl<_ToDur, __cf, __cr,
292 __cf::num == 1, __cf::den == 1>;
293 return __dc::__cast(__d);
294#if __cpp_inline_variables && __cpp_if_constexpr
295 }
296#endif
297 }
298
299 /** Trait indicating whether to treat a type as a floating-point type.
300 *
301 * The chrono library uses this trait to tell whether a `duration` can
302 * represent fractional values of the given precision, or only integral
303 * values.
304 *
305 * You should specialize this trait for your own numeric types that are
306 * used with `duration` and can represent non-integral values.
307 *
308 * @since C++11
309 */
310 template<typename _Rep>
311 struct treat_as_floating_point
312 : is_floating_point<_Rep>
313 { };
314
315#if __cplusplus > 201402L
316 template <typename _Rep>
317 inline constexpr bool treat_as_floating_point_v =
318 treat_as_floating_point<_Rep>::value;
319
320 template<>
321 inline constexpr bool treat_as_floating_point_v<int> = false;
322 template<>
323 inline constexpr bool treat_as_floating_point_v<long> = false;
324 template<>
325 inline constexpr bool treat_as_floating_point_v<long long> = false;
326 template<>
327 inline constexpr bool treat_as_floating_point_v<float> = true;
328 template<>
329 inline constexpr bool treat_as_floating_point_v<double> = true;
330 template<>
331 inline constexpr bool treat_as_floating_point_v<long double> = true;
332#endif // C++17
333
334#if __cplusplus > 201703L
335#if __cpp_lib_concepts
336 template<typename _Tp>
337 inline constexpr bool is_clock_v = false;
338
339 template<typename _Tp>
340 requires requires {
341 typename _Tp::rep;
342 typename _Tp::period;
343 typename _Tp::duration;
344 typename _Tp::time_point::clock;
345 typename _Tp::time_point::duration;
346 { &_Tp::is_steady } -> same_as<const bool*>;
347 { _Tp::now() } -> same_as<typename _Tp::time_point>;
348 requires same_as<typename _Tp::duration,
349 duration<typename _Tp::rep, typename _Tp::period>>;
350 requires same_as<typename _Tp::time_point::duration,
351 typename _Tp::duration>;
352 }
353 inline constexpr bool is_clock_v<_Tp> = true;
354#else
355 template<typename _Tp, typename = void>
356 inline constexpr bool is_clock_v = false;
357
358 template<typename _Tp>
359 inline constexpr bool
360 is_clock_v<_Tp, void_t<typename _Tp::rep, typename _Tp::period,
361 typename _Tp::duration,
362 typename _Tp::time_point::duration,
363 decltype(_Tp::is_steady),
364 decltype(_Tp::now())>>
365 = __and_v<is_same<typename _Tp::duration,
366 duration<typename _Tp::rep, typename _Tp::period>>,
367 is_same<typename _Tp::time_point::duration,
368 typename _Tp::duration>,
369 is_same<decltype(&_Tp::is_steady), const bool*>,
370 is_same<decltype(_Tp::now()), typename _Tp::time_point>>;
371#endif
372
373 template<typename _Tp>
374 struct is_clock
375 : bool_constant<is_clock_v<_Tp>>
376 { };
377#endif // C++20
378
379#if __cplusplus >= 201703L // C++ >= 17
380 /** Convert a `duration` to type `ToDur` and round down.
381 *
382 * If the duration cannot be represented exactly in the result type,
383 * returns the closest value that is less than the argument.
384 *
385 * @tparam _ToDur The result type must be a `duration`.
386 * @param __d A duration.
387 * @return The value of `__d` converted to type `_ToDur`.
388 * @since C++17
389 */
390 template<typename _ToDur, typename _Rep, typename _Period>
391 [[nodiscard]] constexpr __enable_if_is_duration<_ToDur>
392 floor(const duration<_Rep, _Period>& __d)
393 {
394 auto __to = chrono::duration_cast<_ToDur>(__d);
395 if (__to > __d)
396 return __to - _ToDur{1};
397 return __to;
398 }
399
400 /** Convert a `duration` to type `ToDur` and round up.
401 *
402 * If the duration cannot be represented exactly in the result type,
403 * returns the closest value that is greater than the argument.
404 *
405 * @tparam _ToDur The result type must be a `duration`.
406 * @param __d A duration.
407 * @return The value of `__d` converted to type `_ToDur`.
408 * @since C++17
409 */
410 template<typename _ToDur, typename _Rep, typename _Period>
411 [[nodiscard]] constexpr __enable_if_is_duration<_ToDur>
412 ceil(const duration<_Rep, _Period>& __d)
413 {
414 auto __to = chrono::duration_cast<_ToDur>(__d);
415 if (__to < __d)
416 return __to + _ToDur{1};
417 return __to;
418 }
419
420 /** Convert a `duration` to type `ToDur` and round to the closest value.
421 *
422 * If the duration cannot be represented exactly in the result type,
423 * returns the closest value, rounding ties to even.
424 *
425 * @tparam _ToDur The result type must be a `duration` with a
426 * non-floating-point `rep` type.
427 * @param __d A duration.
428 * @return The value of `__d` converted to type `_ToDur`.
429 * @since C++17
430 */
431 template <typename _ToDur, typename _Rep, typename _Period>
432 [[nodiscard]] constexpr
433 enable_if_t<
434 __and_<__is_duration<_ToDur>,
435 __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
436 _ToDur>
437 round(const duration<_Rep, _Period>& __d)
438 {
439 _ToDur __t0 = chrono::floor<_ToDur>(__d);
440 _ToDur __t1 = __t0 + _ToDur{1};
441 auto __diff0 = __d - __t0;
442 auto __diff1 = __t1 - __d;
443 if (__diff0 == __diff1)
444 {
445 if (__t0.count() & 1)
446 return __t1;
447 return __t0;
448 }
449 else if (__diff0 < __diff1)
450 return __t0;
451 return __t1;
452 }
453
454 /** The absolute (non-negative) value of a duration.
455 *
456 * @param __d A duration with a signed `rep` type.
457 * @return A duration of the same type as the argument, with value |d|.
458 * @since C++17
459 */
460 template<typename _Rep, typename _Period>
461 [[nodiscard]] constexpr
462 enable_if_t<numeric_limits<_Rep>::is_signed, duration<_Rep, _Period>>
463 abs(duration<_Rep, _Period> __d)
464 {
465 if (__d >= __d.zero())
466 return __d;
467 return -__d;
468 }
469
470 // Make chrono::ceil<D> also usable as chrono::__detail::ceil<D>.
471 namespace __detail { using chrono::ceil; }
472
473#else // ! __glibcxx_chrono
474
475 // We want to use ceil even when compiling for earlier standards versions.
476 // C++11 only allows a single statement in a constexpr function, so we
477 // need to move the comparison into a separate function, __ceil_impl.
478 namespace __detail
479 {
480 template<typename _Tp, typename _Up>
481 constexpr _Tp
482 __ceil_impl(const _Tp& __t, const _Up& __u)
483 {
484 return (__t < __u) ? (__t + _Tp{1}) : __t;
485 }
486
487 // C++11-friendly version of std::chrono::ceil<D> for internal use.
488 template<typename _ToDur, typename _Rep, typename _Period>
489 constexpr _ToDur
490 ceil(const duration<_Rep, _Period>& __d)
491 {
492 return __detail::__ceil_impl(chrono::duration_cast<_ToDur>(__d), __d);
493 }
494 }
495#endif // __glibcxx_chrono
496
497 /// duration_values
498 template<typename _Rep>
499 struct duration_values
500 {
501 static constexpr _Rep
502 zero() noexcept
503 { return _Rep(0); }
504
505 static constexpr _Rep
506 max() noexcept
507 { return numeric_limits<_Rep>::max(); }
508
509 static constexpr _Rep
510 min() noexcept
511 { return numeric_limits<_Rep>::lowest(); }
512 };
513
514 template<typename _Rep, typename _Period>
515 class duration
516 {
517 static_assert(!__is_duration<_Rep>::value,
518 "rep cannot be a std::chrono::duration");
519 static_assert(__is_ratio<_Period>::value,
520 "period must be a specialization of std::ratio");
521 static_assert(_Period::num > 0, "period must be positive");
522
523 template<typename _Rep2>
524 using __is_float = treat_as_floating_point<_Rep2>;
525
526 static constexpr intmax_t
527 _S_gcd(intmax_t __m, intmax_t __n) noexcept
528 {
529 // Duration only allows positive periods so we don't need to
530 // handle negative values here (unlike __static_gcd and std::gcd).
531#if __cplusplus >= 201402L
532 do
533 {
534 intmax_t __rem = __m % __n;
535 __m = __n;
536 __n = __rem;
537 }
538 while (__n != 0);
539 return __m;
540#else
541 // C++11 doesn't allow loops in constexpr functions, but this
542 // recursive version can be more expensive to evaluate.
543 return (__n == 0) ? __m : _S_gcd(__n, __m % __n);
544#endif
545 }
546
547 // _GLIBCXX_RESOLVE_LIB_DEFECTS
548 // 2094. overflow shouldn't participate in overload resolution
549 // 3090. What is [2094] intended to mean?
550 // This only produces a valid type if no overflow occurs.
551 template<typename _R1, typename _R2,
552 intmax_t __gcd1 = _S_gcd(_R1::num, _R2::num),
553 intmax_t __gcd2 = _S_gcd(_R1::den, _R2::den)>
554 using __divide = ratio<(_R1::num / __gcd1) * (_R2::den / __gcd2),
555 (_R1::den / __gcd2) * (_R2::num / __gcd1)>;
556
557 // _Period2 is an exact multiple of _Period
558 template<typename _Period2>
559 using __is_harmonic
560 = __bool_constant<__divide<_Period2, _Period>::den == 1>;
561
562 public:
563
564 using rep = _Rep;
565 using period = typename _Period::type;
566
567 // 20.11.5.1 construction / copy / destroy
568 constexpr duration() = default;
569
570 duration(const duration&) = default;
571
572 // _GLIBCXX_RESOLVE_LIB_DEFECTS
573 // 3050. Conversion specification problem in chrono::duration
574 template<typename _Rep2, typename = _Require<
575 is_convertible<const _Rep2&, rep>,
576 __or_<__is_float<rep>, __not_<__is_float<_Rep2>>>>>
577 constexpr explicit duration(const _Rep2& __rep)
578 : __r(static_cast<rep>(__rep)) { }
579
580 template<typename _Rep2, typename _Period2, typename = _Require<
581 is_convertible<const _Rep2&, rep>,
582 __or_<__is_float<rep>,
583 __and_<__is_harmonic<_Period2>,
584 __not_<__is_float<_Rep2>>>>>>
585 constexpr duration(const duration<_Rep2, _Period2>& __d)
586 : __r(duration_cast<duration>(__d).count()) { }
587
588 ~duration() = default;
589 duration& operator=(const duration&) = default;
590
591 // 20.11.5.2 observer
592 constexpr rep
593 count() const
594 { return __r; }
595
596 // 20.11.5.3 arithmetic
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 constexpr duration<typename common_type<rep>::type, period>
603 operator-() const
604 { return duration<typename common_type<rep>::type, period>(-__r); }
605
606 _GLIBCXX17_CONSTEXPR duration&
607 operator++()
608 {
609 ++__r;
610 return *this;
611 }
612
613 _GLIBCXX17_CONSTEXPR duration
614 operator++(int)
615 { return duration(__r++); }
616
617 _GLIBCXX17_CONSTEXPR duration&
618 operator--()
619 {
620 --__r;
621 return *this;
622 }
623
624 _GLIBCXX17_CONSTEXPR duration
625 operator--(int)
626 { return duration(__r--); }
627
628 _GLIBCXX17_CONSTEXPR duration&
629 operator+=(const duration& __d)
630 {
631 __r += __d.count();
632 return *this;
633 }
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 rep& __rhs)
644 {
645 __r *= __rhs;
646 return *this;
647 }
648
649 _GLIBCXX17_CONSTEXPR duration&
650 operator/=(const rep& __rhs)
651 {
652 __r /= __rhs;
653 return *this;
654 }
655
656 // DR 934.
657 template<typename _Rep2 = rep>
658 _GLIBCXX17_CONSTEXPR
659 __enable_if_t<!treat_as_floating_point<_Rep2>::value, duration&>
660 operator%=(const rep& __rhs)
661 {
662 __r %= __rhs;
663 return *this;
664 }
665
666 template<typename _Rep2 = rep>
667 _GLIBCXX17_CONSTEXPR
668 __enable_if_t<!treat_as_floating_point<_Rep2>::value, duration&>
669 operator%=(const duration& __d)
670 {
671 __r %= __d.count();
672 return *this;
673 }
674
675 // 20.11.5.4 special values
676 static constexpr duration
677 zero() noexcept
678 { return duration(duration_values<rep>::zero()); }
679
680 static constexpr duration
681 min() noexcept
682 { return duration(duration_values<rep>::min()); }
683
684 static constexpr duration
685 max() noexcept
686 { return duration(duration_values<rep>::max()); }
687
688 private:
689 rep __r;
690 };
691
692 /// @{
693 /// @relates std::chrono::duration
694
695 /// The sum of two durations.
696 template<typename _Rep1, typename _Period1,
697 typename _Rep2, typename _Period2>
698 constexpr typename common_type<duration<_Rep1, _Period1>,
699 duration<_Rep2, _Period2>>::type
700 operator+(const duration<_Rep1, _Period1>& __lhs,
701 const duration<_Rep2, _Period2>& __rhs)
702 {
703 typedef duration<_Rep1, _Period1> __dur1;
704 typedef duration<_Rep2, _Period2> __dur2;
705 typedef typename common_type<__dur1,__dur2>::type __cd;
706 return __cd(__cd(__lhs).count() + __cd(__rhs).count());
707 }
708
709 /// The difference between two durations.
710 template<typename _Rep1, typename _Period1,
711 typename _Rep2, typename _Period2>
712 constexpr typename common_type<duration<_Rep1, _Period1>,
713 duration<_Rep2, _Period2>>::type
714 operator-(const duration<_Rep1, _Period1>& __lhs,
715 const duration<_Rep2, _Period2>& __rhs)
716 {
717 typedef duration<_Rep1, _Period1> __dur1;
718 typedef duration<_Rep2, _Period2> __dur2;
719 typedef typename common_type<__dur1,__dur2>::type __cd;
720 return __cd(__cd(__lhs).count() - __cd(__rhs).count());
721 }
722
723 /// @}
724
725 /// @cond undocumented
726
727 // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
728 // is implicitly convertible to it.
729 // _GLIBCXX_RESOLVE_LIB_DEFECTS
730 // 3050. Conversion specification problem in chrono::duration constructor
731 template<typename _Rep1, typename _Rep2,
732 typename _CRep = typename common_type<_Rep1, _Rep2>::type>
733 using __common_rep_t = typename
734 enable_if<is_convertible<const _Rep2&, _CRep>::value, _CRep>::type;
735
736 /// @endcond
737
738 /** @{
739 * Arithmetic operators for chrono::duration
740 * @relates std::chrono::duration
741 */
742
743 template<typename _Rep1, typename _Period, typename _Rep2>
744 constexpr duration<__common_rep_t<_Rep1, _Rep2>, _Period>
745 operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
746 {
747 typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
748 __cd;
749 return __cd(__cd(__d).count() * __s);
750 }
751
752 template<typename _Rep1, typename _Rep2, typename _Period>
753 constexpr duration<__common_rep_t<_Rep2, _Rep1>, _Period>
754 operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
755 { return __d * __s; }
756
757 template<typename _Rep1, typename _Period, typename _Rep2>
758 constexpr
759 duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
760 operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
761 {
762 typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
763 __cd;
764 return __cd(__cd(__d).count() / __s);
765 }
766
767 template<typename _Rep1, typename _Period1,
768 typename _Rep2, typename _Period2>
769 constexpr typename common_type<_Rep1, _Rep2>::type
770 operator/(const duration<_Rep1, _Period1>& __lhs,
771 const duration<_Rep2, _Period2>& __rhs)
772 {
773 typedef duration<_Rep1, _Period1> __dur1;
774 typedef duration<_Rep2, _Period2> __dur2;
775 typedef typename common_type<__dur1,__dur2>::type __cd;
776 return __cd(__lhs).count() / __cd(__rhs).count();
777 }
778
779 // DR 934.
780 template<typename _Rep1, typename _Period, typename _Rep2>
781 constexpr
782 duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
783 operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
784 {
785 typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
786 __cd;
787 return __cd(__cd(__d).count() % __s);
788 }
789
790 template<typename _Rep1, typename _Period1,
791 typename _Rep2, typename _Period2>
792 constexpr typename common_type<duration<_Rep1, _Period1>,
793 duration<_Rep2, _Period2>>::type
794 operator%(const duration<_Rep1, _Period1>& __lhs,
795 const duration<_Rep2, _Period2>& __rhs)
796 {
797 typedef duration<_Rep1, _Period1> __dur1;
798 typedef duration<_Rep2, _Period2> __dur2;
799 typedef typename common_type<__dur1,__dur2>::type __cd;
800 return __cd(__cd(__lhs).count() % __cd(__rhs).count());
801 }
802 /// @}
803
804 // comparisons
805
806 /** @{
807 * Comparisons for chrono::duration
808 * @relates std::chrono::duration
809 */
810
811 template<typename _Rep1, typename _Period1,
812 typename _Rep2, typename _Period2>
813 constexpr bool
814 operator==(const duration<_Rep1, _Period1>& __lhs,
815 const duration<_Rep2, _Period2>& __rhs)
816 {
817 typedef duration<_Rep1, _Period1> __dur1;
818 typedef duration<_Rep2, _Period2> __dur2;
819 typedef typename common_type<__dur1,__dur2>::type __ct;
820 return __ct(__lhs).count() == __ct(__rhs).count();
821 }
822
823 template<typename _Rep1, typename _Period1,
824 typename _Rep2, typename _Period2>
825 constexpr bool
826 operator<(const duration<_Rep1, _Period1>& __lhs,
827 const duration<_Rep2, _Period2>& __rhs)
828 {
829 typedef duration<_Rep1, _Period1> __dur1;
830 typedef duration<_Rep2, _Period2> __dur2;
831 typedef typename common_type<__dur1,__dur2>::type __ct;
832 return __ct(__lhs).count() < __ct(__rhs).count();
833 }
834
835#if __cpp_lib_three_way_comparison
836 template<typename _Rep1, typename _Period1,
837 typename _Rep2, typename _Period2>
838 requires three_way_comparable<common_type_t<_Rep1, _Rep2>>
839 constexpr auto
840 operator<=>(const duration<_Rep1, _Period1>& __lhs,
841 const duration<_Rep2, _Period2>& __rhs)
842 {
843 using __ct = common_type_t<duration<_Rep1, _Period1>,
844 duration<_Rep2, _Period2>>;
845 return __ct(__lhs).count() <=> __ct(__rhs).count();
846 }
847#else
848 template<typename _Rep1, typename _Period1,
849 typename _Rep2, typename _Period2>
850 constexpr bool
851 operator!=(const duration<_Rep1, _Period1>& __lhs,
852 const duration<_Rep2, _Period2>& __rhs)
853 { return !(__lhs == __rhs); }
854#endif
855
856 template<typename _Rep1, typename _Period1,
857 typename _Rep2, typename _Period2>
858 constexpr bool
859 operator<=(const duration<_Rep1, _Period1>& __lhs,
860 const duration<_Rep2, _Period2>& __rhs)
861 { return !(__rhs < __lhs); }
862
863 template<typename _Rep1, typename _Period1,
864 typename _Rep2, typename _Period2>
865 constexpr bool
866 operator>(const duration<_Rep1, _Period1>& __lhs,
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
873 operator>=(const duration<_Rep1, _Period1>& __lhs,
874 const duration<_Rep2, _Period2>& __rhs)
875 { return !(__lhs < __rhs); }
876
877 /// @}
878
879 /// @cond undocumented
880#ifdef _GLIBCXX_USE_C99_STDINT
881# define _GLIBCXX_CHRONO_INT64_T int64_t
882#elif defined __INT64_TYPE__
883# define _GLIBCXX_CHRONO_INT64_T __INT64_TYPE__
884#else
885 static_assert(std::numeric_limits<unsigned long long>::digits >= 64,
886 "Representation type for nanoseconds must have at least 64 bits");
887# define _GLIBCXX_CHRONO_INT64_T long long
888#endif
889 /// @endcond
890
891 /// nanoseconds
892 using nanoseconds = duration<_GLIBCXX_CHRONO_INT64_T, nano>;
893
894 /// microseconds
895 using microseconds = duration<_GLIBCXX_CHRONO_INT64_T, micro>;
896
897 /// milliseconds
898 using milliseconds = duration<_GLIBCXX_CHRONO_INT64_T, milli>;
899
900 /// seconds
901 using seconds = duration<_GLIBCXX_CHRONO_INT64_T>;
902
903 /// minutes
904 using minutes = duration<_GLIBCXX_CHRONO_INT64_T, ratio< 60>>;
905
906 /// hours
907 using hours = duration<_GLIBCXX_CHRONO_INT64_T, ratio<3600>>;
908
909#if __cplusplus > 201703L
910 /// days
911 using days = duration<_GLIBCXX_CHRONO_INT64_T, ratio<86400>>;
912
913 /// weeks
914 using weeks = duration<_GLIBCXX_CHRONO_INT64_T, ratio<604800>>;
915
916 /// years
917 using years = duration<_GLIBCXX_CHRONO_INT64_T, ratio<31556952>>;
918
919 /// months
920 using months = duration<_GLIBCXX_CHRONO_INT64_T, ratio<2629746>>;
921#endif // C++20
922
923#undef _GLIBCXX_CHRONO_INT64_T
924
925 template<typename _Clock, typename _Dur>
926 class time_point
927 {
928 static_assert(__is_duration<_Dur>::value,
929 "duration must be a specialization of std::chrono::duration");
930
931 public:
932 typedef _Clock clock;
933 typedef _Dur duration;
934 typedef typename duration::rep rep;
935 typedef typename duration::period period;
936
937 constexpr time_point() : __d(duration::zero())
938 { }
939
940 constexpr explicit time_point(const duration& __dur)
941 : __d(__dur)
942 { }
943
944 // conversions
945 template<typename _Dur2,
946 typename = _Require<is_convertible<_Dur2, _Dur>>>
947 constexpr time_point(const time_point<clock, _Dur2>& __t)
948 : __d(__t.time_since_epoch())
949 { }
950
951 // observer
952 constexpr duration
953 time_since_epoch() const
954 { return __d; }
955
956#if __cplusplus > 201703L
957 constexpr time_point&
958 operator++()
959 {
960 ++__d;
961 return *this;
962 }
963
964 constexpr time_point
965 operator++(int)
966 { return time_point{__d++}; }
967
968 constexpr time_point&
969 operator--()
970 {
971 --__d;
972 return *this;
973 }
974
975 constexpr time_point
976 operator--(int)
977 { return time_point{__d--}; }
978#endif
979
980 // arithmetic
981 _GLIBCXX17_CONSTEXPR time_point&
982 operator+=(const duration& __dur)
983 {
984 __d += __dur;
985 return *this;
986 }
987
988 _GLIBCXX17_CONSTEXPR time_point&
989 operator-=(const duration& __dur)
990 {
991 __d -= __dur;
992 return *this;
993 }
994
995 // special values
996 static constexpr time_point
997 min() noexcept
998 { return time_point(duration::min()); }
999
1000 static constexpr time_point
1001 max() noexcept
1002 { return time_point(duration::max()); }
1003
1004 private:
1005 duration __d;
1006 };
1007
1008 /** Convert a `time_point` to use `duration` type `ToDur`.
1009 *
1010 * The result is the same time point as measured by the same clock, but
1011 * using the specified `duration` to represent the time.
1012 * If the time point cannot be represented accurately in the result type,
1013 * returns the result of integer truncation (i.e., rounded towards zero).
1014 *
1015 * @tparam _ToDur The `duration` type to use for the result.
1016 * @param __t A time point.
1017 * @return The value of `__t` converted to use type `_ToDur`.
1018 * @since C++11
1019 */
1020 template<typename _ToDur, typename _Clock, typename _Dur>
1021 _GLIBCXX_NODISCARD constexpr
1022 __enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
1023 time_point_cast(const time_point<_Clock, _Dur>& __t)
1024 {
1025 typedef time_point<_Clock, _ToDur> __time_point;
1026 return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
1027 }
1028
1029#if __cplusplus > 201402L
1030 /** Convert a `time_point` to type `ToDur` and round down.
1031 *
1032 * The result is the same time point as measured by the same clock, but
1033 * using the specified `duration` to represent the time.
1034 * If the time point cannot be represented exactly in the result type,
1035 * returns the closest value that is less than the argument.
1036 *
1037 * @tparam _ToDur The `duration` type to use for the result.
1038 * @param __tp A time point.
1039 * @return The value of `__tp` rounded down to the precision of `_ToDur`.
1040 * @since C++17
1041 */
1042 template<typename _ToDur, typename _Clock, typename _Dur>
1043 [[nodiscard]] constexpr
1044 enable_if_t<__is_duration_v<_ToDur>, time_point<_Clock, _ToDur>>
1045 floor(const time_point<_Clock, _Dur>& __tp)
1046 {
1047 return time_point<_Clock, _ToDur>{
1048 chrono::floor<_ToDur>(__tp.time_since_epoch())};
1049 }
1050
1051 /** Convert a `time_point` to type `ToDur` and round up.
1052 *
1053 * The result is the same time point as measured by the same clock, but
1054 * using the specified `duration` to represent the time.
1055 * If the time point cannot be represented exactly in the result type,
1056 * returns the closest value that is greater than the argument.
1057 *
1058 * @tparam _ToDur The `duration` type to use for the result.
1059 * @param __tp A time point.
1060 * @return The value of `__tp` rounded up to the precision of `_ToDur`.
1061 * @since C++17
1062 */
1063 template<typename _ToDur, typename _Clock, typename _Dur>
1064 [[nodiscard]] constexpr
1065 enable_if_t<__is_duration_v<_ToDur>, time_point<_Clock, _ToDur>>
1066 ceil(const time_point<_Clock, _Dur>& __tp)
1067 {
1068 return time_point<_Clock, _ToDur>{
1069 chrono::ceil<_ToDur>(__tp.time_since_epoch())};
1070 }
1071
1072 /** Convert a `time_point` to type `ToDur` and round to the closest value.
1073 *
1074 * The result is the same time point as measured by the same clock, but
1075 * using the specified `duration` to represent the time.
1076 * If the time point cannot be represented exactly in the result type,
1077 * returns the closest value, rounding ties to even.
1078 *
1079 * @tparam _ToDur The `duration` type to use for the result,
1080 * which must have a non-floating-point `rep` type.
1081 * @param __tp A time point.
1082 * @return The value of `__tp` rounded to the precision `_ToDur`.
1083 * @since C++17
1084 */
1085 template<typename _ToDur, typename _Clock, typename _Dur>
1086 [[nodiscard]] constexpr
1087 enable_if_t<__is_duration_v<_ToDur>
1088 && !treat_as_floating_point_v<typename _ToDur::rep>,
1089 time_point<_Clock, _ToDur>>
1090 round(const time_point<_Clock, _Dur>& __tp)
1091 {
1092 return time_point<_Clock, _ToDur>{
1093 chrono::round<_ToDur>(__tp.time_since_epoch())};
1094 }
1095#endif // C++17
1096
1097 /// @{
1098 /// @relates time_point
1099
1100 /// Adjust a time point forwards by the given duration.
1101 template<typename _Clock, typename _Dur1,
1102 typename _Rep2, typename _Period2>
1103 constexpr time_point<_Clock,
1104 typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
1105 operator+(const time_point<_Clock, _Dur1>& __lhs,
1106 const duration<_Rep2, _Period2>& __rhs)
1107 {
1108 typedef duration<_Rep2, _Period2> __dur2;
1109 typedef typename common_type<_Dur1,__dur2>::type __ct;
1110 typedef time_point<_Clock, __ct> __time_point;
1111 return __time_point(__lhs.time_since_epoch() + __rhs);
1112 }
1113
1114 /// Adjust a time point forwards by the given duration.
1115 template<typename _Rep1, typename _Period1,
1116 typename _Clock, typename _Dur2>
1117 constexpr time_point<_Clock,
1118 typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
1119 operator+(const duration<_Rep1, _Period1>& __lhs,
1120 const time_point<_Clock, _Dur2>& __rhs)
1121 {
1122 typedef duration<_Rep1, _Period1> __dur1;
1123 typedef typename common_type<__dur1,_Dur2>::type __ct;
1124 typedef time_point<_Clock, __ct> __time_point;
1125 return __time_point(__rhs.time_since_epoch() + __lhs);
1126 }
1127
1128 /// Adjust a time point backwards by the given duration.
1129 template<typename _Clock, typename _Dur1,
1130 typename _Rep2, typename _Period2>
1131 constexpr time_point<_Clock,
1132 typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
1133 operator-(const time_point<_Clock, _Dur1>& __lhs,
1134 const duration<_Rep2, _Period2>& __rhs)
1135 {
1136 typedef duration<_Rep2, _Period2> __dur2;
1137 typedef typename common_type<_Dur1,__dur2>::type __ct;
1138 typedef time_point<_Clock, __ct> __time_point;
1139 return __time_point(__lhs.time_since_epoch() -__rhs);
1140 }
1141
1142 /// The difference between two time points (as a duration)
1143 template<typename _Clock, typename _Dur1, typename _Dur2>
1144 constexpr typename common_type<_Dur1, _Dur2>::type
1145 operator-(const time_point<_Clock, _Dur1>& __lhs,
1146 const time_point<_Clock, _Dur2>& __rhs)
1147 { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
1148 /// @}
1149
1150 /** @{
1151 * Comparisons for time_point
1152 * @relates chrono::time_point
1153 */
1154
1155 template<typename _Clock, typename _Dur1, typename _Dur2>
1156 constexpr bool
1157 operator==(const time_point<_Clock, _Dur1>& __lhs,
1158 const time_point<_Clock, _Dur2>& __rhs)
1159 { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
1160
1161#if __cpp_lib_three_way_comparison
1162 template<typename _Clock, typename _Dur1,
1163 three_way_comparable_with<_Dur1> _Dur2>
1164 constexpr auto
1165 operator<=>(const time_point<_Clock, _Dur1>& __lhs,
1166 const time_point<_Clock, _Dur2>& __rhs)
1167 { return __lhs.time_since_epoch() <=> __rhs.time_since_epoch(); }
1168#else
1169 template<typename _Clock, typename _Dur1, typename _Dur2>
1170 constexpr bool
1171 operator!=(const time_point<_Clock, _Dur1>& __lhs,
1172 const time_point<_Clock, _Dur2>& __rhs)
1173 { return !(__lhs == __rhs); }
1174#endif
1175
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.time_since_epoch() < __rhs.time_since_epoch(); }
1181
1182 template<typename _Clock, typename _Dur1, typename _Dur2>
1183 constexpr bool
1184 operator<=(const time_point<_Clock, _Dur1>& __lhs,
1185 const time_point<_Clock, _Dur2>& __rhs)
1186 { return !(__rhs < __lhs); }
1187
1188 template<typename _Clock, typename _Dur1, typename _Dur2>
1189 constexpr bool
1190 operator>(const time_point<_Clock, _Dur1>& __lhs,
1191 const time_point<_Clock, _Dur2>& __rhs)
1192 { return __rhs < __lhs; }
1193
1194 template<typename _Clock, typename _Dur1, typename _Dur2>
1195 constexpr bool
1196 operator>=(const time_point<_Clock, _Dur1>& __lhs,
1197 const time_point<_Clock, _Dur2>& __rhs)
1198 { return !(__lhs < __rhs); }
1199
1200 /// @}
1201 /// @} group chrono
1202
1203#if _GLIBCXX_HOSTED
1204 // Clocks.
1205
1206 // Why nanosecond resolution as the default?
1207 // Why have std::system_clock always count in the highest
1208 // resolution (ie nanoseconds), even if on some OSes the low 3
1209 // or 9 decimal digits will be always zero? This allows later
1210 // implementations to change the system_clock::now()
1211 // implementation any time to provide better resolution without
1212 // changing function signature or units.
1213
1214 // To support the (forward) evolution of the library's defined
1215 // clocks, wrap inside inline namespace so that the current
1216 // defintions of system_clock, steady_clock, and
1217 // high_resolution_clock types are uniquely mangled. This way, new
1218 // code can use the latests clocks, while the library can contain
1219 // compatibility definitions for previous versions. At some
1220 // point, when these clocks settle down, the inlined namespaces
1221 // can be removed. XXX GLIBCXX_ABI Deprecated
1222_GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2)
1223
1224 /**
1225 * @brief System clock.
1226 *
1227 * Time returned represents wall time from the system-wide clock.
1228 * @ingroup chrono
1229 */
1230 struct system_clock
1231 {
1232 typedef chrono::nanoseconds duration;
1233 typedef duration::rep rep;
1234 typedef duration::period period;
1235 typedef chrono::time_point<system_clock, duration> time_point;
1236
1237 static_assert(system_clock::duration::min()
1238 < system_clock::duration::zero(),
1239 "a clock's minimum duration cannot be less than its epoch");
1240
1241 static constexpr bool is_steady = false;
1242
1243 static time_point
1244 now() noexcept;
1245
1246 // Map to C API
1247 [[__gnu__::__always_inline__]]
1248 static std::time_t
1249 to_time_t(const time_point& __t) noexcept
1250 {
1251 return std::time_t(duration_cast<chrono::seconds>
1252 (__t.time_since_epoch()).count());
1253 }
1254
1255 [[__gnu__::__always_inline__]]
1256 static time_point
1257 from_time_t(std::time_t __t) noexcept
1258 {
1259 typedef chrono::time_point<system_clock, seconds> __from;
1260 return time_point_cast<system_clock::duration>
1261 (__from(chrono::seconds(__t)));
1262 }
1263 };
1264
1265
1266 /**
1267 * @brief Monotonic clock
1268 *
1269 * Time returned has the property of only increasing at a uniform rate.
1270 * @ingroup chrono
1271 */
1272 struct steady_clock
1273 {
1274 typedef chrono::nanoseconds duration;
1275 typedef duration::rep rep;
1276 typedef duration::period period;
1277 typedef chrono::time_point<steady_clock, duration> time_point;
1278
1279 static constexpr bool is_steady = true;
1280
1281 static time_point
1282 now() noexcept;
1283 };
1284
1285
1286 /**
1287 * @brief Highest-resolution clock
1288 *
1289 * This is the clock "with the shortest tick period." Alias to
1290 * std::system_clock until higher-than-nanosecond definitions
1291 * become feasible.
1292 * @ingroup chrono
1293 */
1294 using high_resolution_clock = system_clock;
1295
1296_GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
1297
1298#if __cplusplus >= 202002L
1299 /// @addtogroup chrono
1300 /// @{
1301 template<typename _Duration>
1302 using sys_time = time_point<system_clock, _Duration>;
1303 using sys_seconds = sys_time<seconds>;
1304 using sys_days = sys_time<days>;
1305
1306 using file_clock = ::std::filesystem::__file_clock;
1307
1308 template<typename _Duration>
1309 using file_time = time_point<file_clock, _Duration>;
1310
1311 template<> struct is_clock<system_clock> : true_type { };
1312 template<> struct is_clock<steady_clock> : true_type { };
1313 template<> struct is_clock<file_clock> : true_type { };
1314
1315 template<> inline constexpr bool is_clock_v<system_clock> = true;
1316 template<> inline constexpr bool is_clock_v<steady_clock> = true;
1317 template<> inline constexpr bool is_clock_v<file_clock> = true;
1318 /// @}
1319#endif // C++20
1320#elif __cplusplus >= 202002L
1321 // Define a fake clock like chrono::local_t so that sys_time etc.
1322 // can be used for freestanding.
1323 struct __sys_t;
1324 template<typename _Duration>
1325 using sys_time = time_point<__sys_t, _Duration>;
1326 using sys_seconds = sys_time<seconds>;
1327 using sys_days = sys_time<days>;
1328#endif // _GLIBCXX_HOSTED
1329 } // namespace chrono
1330
1331#ifdef __glibcxx_chrono_udls // C++ >= 14
1332 inline namespace literals
1333 {
1334 /** ISO C++ 2014 namespace for suffixes for duration literals.
1335 *
1336 * These suffixes can be used to create `chrono::duration` values with
1337 * tick periods of hours, minutes, seconds, milliseconds, microseconds
1338 * or nanoseconds. For example, `std::chrono::seconds(5)` can be written
1339 * as `5s` after making the suffix visible in the current scope.
1340 * The suffixes can be made visible by a using-directive or
1341 * using-declaration such as:
1342 * - `using namespace std::chrono_literals;`
1343 * - `using namespace std::literals;`
1344 * - `using namespace std::chrono;`
1345 * - `using namespace std;`
1346 * - `using std::chrono_literals::operator""s;`
1347 *
1348 * The result of these suffixes on an integer literal is one of the
1349 * standard typedefs such as `std::chrono::hours`.
1350 * The result on a floating-point literal is a duration type with the
1351 * specified tick period and an unspecified floating-point representation,
1352 * for example `1.5e2ms` might be equivalent to
1353 * `chrono::duration<long double, chrono::milli>(1.5e2)`.
1354 *
1355 * @since C+14
1356 * @ingroup chrono
1357 */
1358 inline namespace chrono_literals
1359 {
1360 /// @addtogroup chrono
1361 /// @{
1362
1363#pragma GCC diagnostic push
1364#pragma GCC diagnostic ignored "-Wliteral-suffix"
1365 /// @cond undocumented
1366 template<typename _Dur, char... _Digits>
1367 constexpr _Dur __check_overflow()
1368 {
1369 using _Val = __parse_int::_Parse_int<_Digits...>;
1370 constexpr typename _Dur::rep __repval = _Val::value;
1371 static_assert(__repval >= 0 && __repval == _Val::value,
1372 "literal value cannot be represented by duration type");
1373 return _Dur(__repval);
1374 }
1375 /// @endcond
1376
1377 /// Literal suffix for durations representing non-integer hours
1378 constexpr chrono::duration<long double, ratio<3600,1>>
1379 operator""h(long double __hours)
1380 { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
1381
1382 /// Literal suffix for durations of type `std::chrono::hours`
1383 template <char... _Digits>
1384 constexpr chrono::hours
1385 operator""h()
1386 { return __check_overflow<chrono::hours, _Digits...>(); }
1387
1388 /// Literal suffix for durations representing non-integer minutes
1389 constexpr chrono::duration<long double, ratio<60,1>>
1390 operator""min(long double __mins)
1391 { return chrono::duration<long double, ratio<60,1>>{__mins}; }
1392
1393 /// Literal suffix for durations of type `std::chrono::minutes`
1394 template <char... _Digits>
1395 constexpr chrono::minutes
1396 operator""min()
1397 { return __check_overflow<chrono::minutes, _Digits...>(); }
1398
1399 /// Literal suffix for durations representing non-integer seconds
1400 constexpr chrono::duration<long double>
1401 operator""s(long double __secs)
1402 { return chrono::duration<long double>{__secs}; }
1403
1404 /// Literal suffix for durations of type `std::chrono::seconds`
1405 template <char... _Digits>
1406 constexpr chrono::seconds
1407 operator""s()
1408 { return __check_overflow<chrono::seconds, _Digits...>(); }
1409
1410 /// Literal suffix for durations representing non-integer milliseconds
1411 constexpr chrono::duration<long double, milli>
1412 operator""ms(long double __msecs)
1413 { return chrono::duration<long double, milli>{__msecs}; }
1414
1415 /// Literal suffix for durations of type `std::chrono::milliseconds`
1416 template <char... _Digits>
1417 constexpr chrono::milliseconds
1418 operator""ms()
1419 { return __check_overflow<chrono::milliseconds, _Digits...>(); }
1420
1421 /// Literal suffix for durations representing non-integer microseconds
1422 constexpr chrono::duration<long double, micro>
1423 operator""us(long double __usecs)
1424 { return chrono::duration<long double, micro>{__usecs}; }
1425
1426 /// Literal suffix for durations of type `std::chrono::microseconds`
1427 template <char... _Digits>
1428 constexpr chrono::microseconds
1429 operator""us()
1430 { return __check_overflow<chrono::microseconds, _Digits...>(); }
1431
1432 /// Literal suffix for durations representing non-integer nanoseconds
1433 constexpr chrono::duration<long double, nano>
1434 operator""ns(long double __nsecs)
1435 { return chrono::duration<long double, nano>{__nsecs}; }
1436
1437 /// Literal suffix for durations of type `std::chrono::nanoseconds`
1438 template <char... _Digits>
1439 constexpr chrono::nanoseconds
1440 operator""ns()
1441 { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
1442
1443#pragma GCC diagnostic pop
1444 /// @}
1445 } // inline namespace chrono_literals
1446 } // inline namespace literals
1447
1448 namespace chrono
1449 {
1450 using namespace literals::chrono_literals;
1451 } // namespace chrono
1452#endif // __glibcxx_chrono_udls
1453
1454#if __cplusplus >= 201703L && _GLIBCXX_HOSTED
1455 namespace filesystem
1456 {
1457 struct __file_clock
1458 {
1459 using duration = chrono::nanoseconds;
1460 using rep = duration::rep;
1461 using period = duration::period;
1462 using time_point = chrono::time_point<__file_clock>;
1463 static constexpr bool is_steady = false;
1464
1465 static time_point
1466 now() noexcept
1467 { return _S_from_sys(chrono::system_clock::now()); }
1468
1469#if __cplusplus > 201703L
1470 template<typename _Dur>
1471 static
1472 chrono::file_time<common_type_t<_Dur, chrono::seconds>>
1473 from_sys(const chrono::sys_time<_Dur>& __t) noexcept
1474 { return _S_from_sys(__t); }
1475
1476 // For internal use only
1477 template<typename _Dur>
1478 static
1479 chrono::sys_time<common_type_t<_Dur, chrono::seconds>>
1480 to_sys(const chrono::file_time<_Dur>& __t) noexcept
1481 { return _S_to_sys(__t); }
1482#endif // C++20
1483
1484 private:
1485 using __sys_clock = chrono::system_clock;
1486
1487 // This clock's (unspecified) epoch is 2174-01-01 00:00:00 UTC.
1488 // A signed 64-bit duration with nanosecond resolution gives roughly
1489 // +/- 292 years, which covers the 1901-2446 date range for ext4.
1490 static constexpr chrono::seconds _S_epoch_diff{6437664000};
1491
1492 protected:
1493 // For internal use only
1494 template<typename _Dur>
1495 static
1496 chrono::time_point<__file_clock, common_type_t<_Dur, chrono::seconds>>
1497 _S_from_sys(const chrono::time_point<__sys_clock, _Dur>& __t) noexcept
1498 {
1499 using _CDur = common_type_t<_Dur, chrono::seconds>;
1500 using __file_time = chrono::time_point<__file_clock, _CDur>;
1501 return __file_time{__t.time_since_epoch()} - _S_epoch_diff;
1502 }
1503
1504 // For internal use only
1505 template<typename _Dur>
1506 static
1507 chrono::time_point<__sys_clock, common_type_t<_Dur, chrono::seconds>>
1508 _S_to_sys(const chrono::time_point<__file_clock, _Dur>& __t) noexcept
1509 {
1510 using _CDur = common_type_t<_Dur, chrono::seconds>;
1511 using __sys_time = chrono::time_point<__sys_clock, _CDur>;
1512 return __sys_time{__t.time_since_epoch()} + _S_epoch_diff;
1513 }
1514 };
1515 } // namespace filesystem
1516#endif // C++17 && HOSTED
1517
1518#if _GLIBCXX_HOSTED
1519#if ! defined _GLIBCXX_NO_SLEEP || defined _GLIBCXX_HAS_GTHREADS \
1520 || _GLIBCXX_HAVE_LINUX_FUTEX
1521namespace chrono
1522{
1523/// @cond undocumented
1524
1525#pragma GCC diagnostic push
1526#pragma GCC diagnostic ignored "-Wc++17-extensions"
1527 // Convert a chrono::duration to a relative time represented as timespec
1528 // (e.g. for use with nanosleep).
1529 template<typename _Rep, typename _Period>
1530 [[__nodiscard__]] _GLIBCXX14_CONSTEXPR inline
1531 struct ::timespec
1532 __to_timeout_timespec(const duration<_Rep, _Period>& __d)
1533 {
1534 struct ::timespec __ts{};
1535
1536 if (__d < __d.zero()) // Negative timeouts don't make sense.
1537 return __ts;
1538
1539 if constexpr (ratio_greater<_Period, ratio<1>>::value
1540 || treat_as_floating_point<_Rep>::value)
1541 {
1542 // Converting from e.g. chrono::hours::max() to chrono::seconds
1543 // would evaluate LLONG_MAX * 3600 which would overflow.
1544 // Limit to chrono::seconds::max().
1545 chrono::duration<double> __fmax(chrono::seconds::max());
1546 if (__d > __fmax) [[__unlikely__]]
1547 return chrono::__to_timeout_timespec(chrono::seconds::max());
1548 }
1549
1550 auto __s = chrono::duration_cast<chrono::seconds>(__d);
1551
1552 if constexpr (is_integral<time_t>::value) // POSIX.1-2001 allows floating
1553 {
1554 // Also limit to time_t maximum (only relevant for 32-bit time_t).
1555 constexpr auto __tmax = numeric_limits<time_t>::max();
1556 if (__s.count() > __tmax) [[__unlikely__]]
1557 {
1558 __ts.tv_sec = __tmax;
1559 return __ts;
1560 }
1561 }
1562
1563 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__d - __s);
1564
1565 if constexpr (treat_as_floating_point<_Rep>::value)
1566 if (__ns.count() > 999999999) [[__unlikely__]]
1567 __ns = chrono::nanoseconds(999999999);
1568
1569 __ts.tv_sec = static_cast<time_t>(__s.count());
1570 __ts.tv_nsec = static_cast<long>(__ns.count());
1571 return __ts;
1572 }
1573#pragma GCC diagnostic pop
1574
1575 // Convert a chrono::time_point to an absolute time represented as timespec.
1576 // All times before the epoch get converted to the epoch, so this assumes
1577 // that we only use it for clocks where that's true.
1578 // It should be safe to use this for system_clock and steady_clock.
1579 template<typename _Clock, typename _Dur>
1580 [[__nodiscard__]] _GLIBCXX14_CONSTEXPR inline
1581 struct ::timespec
1582 __to_timeout_timespec(const time_point<_Clock, _Dur>& __t)
1583 {
1584 return chrono::__to_timeout_timespec(__t.time_since_epoch());
1585 }
1586
1587/// @endcond
1588} // namespace chrono
1589#endif // !NO_SLEEP || HAS_GTHREADS || HAVE_LINUX_FUTEX
1590#endif // HOSTED
1591
1592_GLIBCXX_END_NAMESPACE_VERSION
1593} // namespace std
1594
1595#endif // C++11
1596
1597#endif //_GLIBCXX_CHRONO_H
compare
concepts
limits
ratio
type_traits
ctime
parse_numbers.h
version.h
std::chrono::__detail::ceil
constexpr __enable_if_is_duration< _ToDur > ceil(const duration< _Rep, _Period > &__d)
Definition chrono.h:412
std::chrono::duration::operator==
constexpr bool operator==(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:814
std::chrono::weeks
duration< int64_t, ratio< 604800 > > weeks
weeks
Definition chrono.h:914
std::chrono::floor
constexpr __enable_if_is_duration< _ToDur > floor(const duration< _Rep, _Period > &__d)
Definition chrono.h:392
std::chrono::months
duration< int64_t, ratio< 2629746 > > months
months
Definition chrono.h:920
std::chrono::round
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:437
std::chrono::days
duration< int64_t, ratio< 86400 > > days
days
Definition chrono.h:911
std::chrono::years
duration< int64_t, ratio< 31556952 > > years
years
Definition chrono.h:917
std::chrono::operator<=
constexpr bool operator<=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:859
std::chrono::hours
duration< int64_t, ratio< 3600 > > hours
hours
Definition chrono.h:907
std::chrono::operator>=
constexpr bool operator>=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:873
std::chrono::high_resolution_clock
system_clock high_resolution_clock
Highest-resolution clock.
Definition chrono.h:1294
std::chrono::operator*
constexpr duration< __common_rep_t< _Rep2, _Rep1 >, _Period > operator*(const _Rep1 &__s, const duration< _Rep2, _Period > &__d)
Definition chrono.h:754
std::chrono::nanoseconds
duration< int64_t, nano > nanoseconds
nanoseconds
Definition chrono.h:892
std::chrono::abs
constexpr enable_if_t< numeric_limits< _Rep >::is_signed, duration< _Rep, _Period > > abs(duration< _Rep, _Period > __d)
Definition chrono.h:463
std::chrono::operator%
constexpr duration< __common_rep_t< _Rep1, __disable_if_is_duration< _Rep2 > >, _Period > operator%(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition chrono.h:783
std::chrono::time_point< local_t, _Duration >::operator+
constexpr time_point< local_t, typename common_type< _Dur1, duration< _Rep2, _Period2 > >::type > operator+(const time_point< local_t, _Dur1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:1105
std::chrono::minutes
duration< int64_t, ratio< 60 > > minutes
minutes
Definition chrono.h:904
std::chrono::time_point_cast
constexpr __enable_if_t< __is_duration< _ToDur >::value, time_point< _Clock, _ToDur > > time_point_cast(const time_point< _Clock, _Dur > &__t)
Definition chrono.h:1023
std::chrono::milliseconds
duration< int64_t, milli > milliseconds
milliseconds
Definition chrono.h:898
std::chrono::microseconds
duration< int64_t, micro > microseconds
microseconds
Definition chrono.h:895
std::chrono::operator+
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:1119
std::chrono::duration::operator+
constexpr common_type< duration< _Rep1, _Period1 >, duration< _Rep2, _Period2 > >::type operator+(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
The sum of two durations.
Definition chrono.h:700
std::chrono::operator<
constexpr bool operator<(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:826
std::chrono::seconds
duration< int64_t > seconds
seconds
Definition chrono.h:901
std::chrono::operator>
constexpr bool operator>(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:866
std::chrono::operator-
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:714
std::chrono::operator/
constexpr duration< __common_rep_t< _Rep1, __disable_if_is_duration< _Rep2 > >, _Period > operator/(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition chrono.h:760
std::chrono::duration::operator*
constexpr duration< __common_rep_t< _Rep1, _Rep2 >, _Period > operator*(const duration< _Rep1, _Period > &__d, const _Rep2 &__s)
Definition chrono.h:745
std::chrono::ceil
constexpr __enable_if_is_duration< _ToDur > ceil(const duration< _Rep, _Period > &__d)
Definition chrono.h:412
std::chrono::operator<=>
constexpr auto operator<=>(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
Definition chrono.h:840
std::chrono::duration_cast
constexpr __enable_if_is_duration< _ToDur > duration_cast(const duration< _Rep, _Period > &__d)
Definition chrono.h:279
std::ratio_divide
typename __ratio_divide< _R1, _R2 >::type ratio_divide
ratio_divide
Definition ratio:392
std::true_type
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:119
std::common_type_t
typename common_type< _Tp... >::type common_type_t
Alias template for common_type.
Definition type_traits:2948
std::enable_if_t
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition type_traits:2940
std::false_type
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:122
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition stl_algobase.h:232
std::experimental::fundamentals_v2::void_t
void void_t
A metafunction that always yields void, used for detecting valid types.
Definition experimental/type_traits:262
std
ISO C++ entities toplevel namespace is std.
std::literals
ISO C++ inline namespace for literal suffixes.
std::__detail
Implementation details not part of the namespace std interface.
std::chrono
ISO C++ 2011 namespace for date and time utilities.
std::literals::chrono_literals
Definition chrono:3669
std::filesystem
ISO C++ 2017 namespace for File System library.
Definition chrono.h:58
std::__numeric_limits_base::digits
static constexpr int digits
Definition limits:218
std::numeric_limits::max
static constexpr _Tp max() noexcept
Definition limits:328
std::numeric_limits::lowest
static constexpr _Tp lowest() noexcept
Definition limits:334
std::ratio
Provides compile-time rational arithmetic.
Definition ratio:272
std::enable_if
Define a member typedef type only if a boolean constant is true.
Definition type_traits:137
std::is_floating_point
is_floating_point
Definition type_traits:601
std::common_type
common_type
Definition type_traits:2573
std::chrono::duration
chrono::duration represents a distance between two points in time
Definition chrono.h:516
std::chrono::time_point
chrono::time_point represents a point in time as measured by a clock
Definition chrono.h:927
std::chrono::treat_as_floating_point
Definition chrono.h:313
std::chrono::duration_values
duration_values
Definition chrono.h:500
std::chrono::system_clock
System clock.
Definition chrono.h:1231
std::chrono::steady_clock
Monotonic clock.
Definition chrono.h:1273
std::same_as
[concept.same], concept same_as
Definition concepts:65