libstdc++
chrono
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1 // <chrono> -*- C++ -*-
2 
3 // Copyright (C) 2008-2016 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/chrono
26  * This is a Standard C++ Library header.
27  */
28 
29 #ifndef _GLIBCXX_CHRONO
30 #define _GLIBCXX_CHRONO 1
31 
32 #pragma GCC system_header
33 
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
36 #else
37 
38 #include <ratio>
39 #include <type_traits>
40 #include <limits>
41 #include <ctime>
42 #include <bits/parse_numbers.h> // for literals support.
43 
44 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
45 
46 namespace std _GLIBCXX_VISIBILITY(default)
47 {
48  /**
49  * @defgroup chrono Time
50  * @ingroup utilities
51  *
52  * Classes and functions for time.
53  * @{
54  */
55 
56  /** @namespace std::chrono
57  * @brief ISO C++ 2011 entities sub-namespace for time and date.
58  */
59  namespace chrono
60  {
61  _GLIBCXX_BEGIN_NAMESPACE_VERSION
62 
63  template<typename _Rep, typename _Period = ratio<1>>
64  struct duration;
65 
66  template<typename _Clock, typename _Dur = typename _Clock::duration>
67  struct time_point;
68 
69  _GLIBCXX_END_NAMESPACE_VERSION
70  }
71 
72 _GLIBCXX_BEGIN_NAMESPACE_VERSION
73 
74  // 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
75 
76  template<typename _CT, typename _Period1, typename _Period2>
77  struct __duration_common_type_wrapper
78  {
79  private:
80  typedef __static_gcd<_Period1::num, _Period2::num> __gcd_num;
81  typedef __static_gcd<_Period1::den, _Period2::den> __gcd_den;
82  typedef typename _CT::type __cr;
83  typedef ratio<__gcd_num::value,
84  (_Period1::den / __gcd_den::value) * _Period2::den> __r;
85  public:
86  typedef __success_type<chrono::duration<__cr, __r>> type;
87  };
88 
89  template<typename _Period1, typename _Period2>
90  struct __duration_common_type_wrapper<__failure_type, _Period1, _Period2>
91  { typedef __failure_type type; };
92 
93  template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
94  struct common_type<chrono::duration<_Rep1, _Period1>,
95  chrono::duration<_Rep2, _Period2>>
96  : public __duration_common_type_wrapper<typename __member_type_wrapper<
97  common_type<_Rep1, _Rep2>>::type, _Period1, _Period2>::type
98  { };
99 
100  // 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
101 
102  template<typename _CT, typename _Clock>
103  struct __timepoint_common_type_wrapper
104  {
105  typedef __success_type<chrono::time_point<_Clock, typename _CT::type>>
106  type;
107  };
108 
109  template<typename _Clock>
110  struct __timepoint_common_type_wrapper<__failure_type, _Clock>
111  { typedef __failure_type type; };
112 
113  template<typename _Clock, typename _Duration1, typename _Duration2>
114  struct common_type<chrono::time_point<_Clock, _Duration1>,
115  chrono::time_point<_Clock, _Duration2>>
116  : public __timepoint_common_type_wrapper<typename __member_type_wrapper<
117  common_type<_Duration1, _Duration2>>::type, _Clock>::type
118  { };
119 
120 _GLIBCXX_END_NAMESPACE_VERSION
121 
122  namespace chrono
123  {
124  _GLIBCXX_BEGIN_NAMESPACE_VERSION
125 
126  // Primary template for duration_cast impl.
127  template<typename _ToDur, typename _CF, typename _CR,
128  bool _NumIsOne = false, bool _DenIsOne = false>
129  struct __duration_cast_impl
130  {
131  template<typename _Rep, typename _Period>
132  static constexpr _ToDur
133  __cast(const duration<_Rep, _Period>& __d)
134  {
135  typedef typename _ToDur::rep __to_rep;
136  return _ToDur(static_cast<__to_rep>(static_cast<_CR>(__d.count())
137  * static_cast<_CR>(_CF::num)
138  / static_cast<_CR>(_CF::den)));
139  }
140  };
141 
142  template<typename _ToDur, typename _CF, typename _CR>
143  struct __duration_cast_impl<_ToDur, _CF, _CR, true, true>
144  {
145  template<typename _Rep, typename _Period>
146  static constexpr _ToDur
147  __cast(const duration<_Rep, _Period>& __d)
148  {
149  typedef typename _ToDur::rep __to_rep;
150  return _ToDur(static_cast<__to_rep>(__d.count()));
151  }
152  };
153 
154  template<typename _ToDur, typename _CF, typename _CR>
155  struct __duration_cast_impl<_ToDur, _CF, _CR, true, false>
156  {
157  template<typename _Rep, typename _Period>
158  static constexpr _ToDur
159  __cast(const duration<_Rep, _Period>& __d)
160  {
161  typedef typename _ToDur::rep __to_rep;
162  return _ToDur(static_cast<__to_rep>(
163  static_cast<_CR>(__d.count()) / static_cast<_CR>(_CF::den)));
164  }
165  };
166 
167  template<typename _ToDur, typename _CF, typename _CR>
168  struct __duration_cast_impl<_ToDur, _CF, _CR, false, true>
169  {
170  template<typename _Rep, typename _Period>
171  static constexpr _ToDur
172  __cast(const duration<_Rep, _Period>& __d)
173  {
174  typedef typename _ToDur::rep __to_rep;
175  return _ToDur(static_cast<__to_rep>(
176  static_cast<_CR>(__d.count()) * static_cast<_CR>(_CF::num)));
177  }
178  };
179 
180  template<typename _Tp>
181  struct __is_duration
183  { };
184 
185  template<typename _Rep, typename _Period>
186  struct __is_duration<duration<_Rep, _Period>>
188  { };
189 
190  /// duration_cast
191  template<typename _ToDur, typename _Rep, typename _Period>
192  constexpr typename enable_if<__is_duration<_ToDur>::value,
193  _ToDur>::type
195  {
196  typedef typename _ToDur::period __to_period;
197  typedef typename _ToDur::rep __to_rep;
199  typedef typename common_type<__to_rep, _Rep, intmax_t>::type
200  __cr;
201  typedef __duration_cast_impl<_ToDur, __cf, __cr,
202  __cf::num == 1, __cf::den == 1> __dc;
203  return __dc::__cast(__d);
204  }
205 
206  /// treat_as_floating_point
207  template<typename _Rep>
209  : is_floating_point<_Rep>
210  { };
211 
212  /// duration_values
213  template<typename _Rep>
215  {
216  static constexpr _Rep
217  zero()
218  { return _Rep(0); }
219 
220  static constexpr _Rep
221  max()
222  { return numeric_limits<_Rep>::max(); }
223 
224  static constexpr _Rep
225  min()
226  { return numeric_limits<_Rep>::lowest(); }
227  };
228 
229  template<typename _Tp>
230  struct __is_ratio
232  { };
233 
234  template<intmax_t _Num, intmax_t _Den>
235  struct __is_ratio<ratio<_Num, _Den>>
237  { };
238 
239  /// duration
240  template<typename _Rep, typename _Period>
241  struct duration
242  {
243  typedef _Rep rep;
244  typedef _Period period;
245 
246  static_assert(!__is_duration<_Rep>::value, "rep cannot be a duration");
247  static_assert(__is_ratio<_Period>::value,
248  "period must be a specialization of ratio");
249  static_assert(_Period::num > 0, "period must be positive");
250 
251  // 20.11.5.1 construction / copy / destroy
252  constexpr duration() = default;
253 
254  // NB: Make constexpr implicit. This cannot be explicitly
255  // constexpr, as any UDT that is not a literal type with a
256  // constexpr copy constructor will be ill-formed.
257  duration(const duration&) = default;
258 
259  // _GLIBCXX_RESOLVE_LIB_DEFECTS
260  // 3050. Conversion specification problem in chrono::duration
261  template<typename _Rep2, typename = typename
262  enable_if<is_convertible<const _Rep2&, rep>::value
263  && (treat_as_floating_point<rep>::value
264  || !treat_as_floating_point<_Rep2>::value)>::type>
265  constexpr explicit duration(const _Rep2& __rep)
266  : __r(static_cast<rep>(__rep)) { }
267 
268  template<typename _Rep2, typename _Period2, typename = typename
269  enable_if<treat_as_floating_point<rep>::value
270  || (ratio_divide<_Period2, period>::den == 1
271  && !treat_as_floating_point<_Rep2>::value)>::type>
272  constexpr duration(const duration<_Rep2, _Period2>& __d)
273  : __r(duration_cast<duration>(__d).count()) { }
274 
275  ~duration() = default;
276  duration& operator=(const duration&) = default;
277 
278  // 20.11.5.2 observer
279  constexpr rep
280  count() const
281  { return __r; }
282 
283  // 20.11.5.3 arithmetic
284  constexpr duration
285  operator+() const
286  { return *this; }
287 
288  constexpr duration
289  operator-() const
290  { return duration(-__r); }
291 
292  duration&
293  operator++()
294  {
295  ++__r;
296  return *this;
297  }
298 
299  duration
300  operator++(int)
301  { return duration(__r++); }
302 
303  duration&
304  operator--()
305  {
306  --__r;
307  return *this;
308  }
309 
310  duration
311  operator--(int)
312  { return duration(__r--); }
313 
314  duration&
315  operator+=(const duration& __d)
316  {
317  __r += __d.count();
318  return *this;
319  }
320 
321  duration&
322  operator-=(const duration& __d)
323  {
324  __r -= __d.count();
325  return *this;
326  }
327 
328  duration&
329  operator*=(const rep& __rhs)
330  {
331  __r *= __rhs;
332  return *this;
333  }
334 
335  duration&
336  operator/=(const rep& __rhs)
337  {
338  __r /= __rhs;
339  return *this;
340  }
341 
342  // DR 934.
343  template<typename _Rep2 = rep>
344  typename enable_if<!treat_as_floating_point<_Rep2>::value,
345  duration&>::type
346  operator%=(const rep& __rhs)
347  {
348  __r %= __rhs;
349  return *this;
350  }
351 
352  template<typename _Rep2 = rep>
353  typename enable_if<!treat_as_floating_point<_Rep2>::value,
354  duration&>::type
355  operator%=(const duration& __d)
356  {
357  __r %= __d.count();
358  return *this;
359  }
360 
361  // 20.11.5.4 special values
362  static constexpr duration
363  zero()
364  { return duration(duration_values<rep>::zero()); }
365 
366  static constexpr duration
367  min()
368  { return duration(duration_values<rep>::min()); }
369 
370  static constexpr duration
371  max()
372  { return duration(duration_values<rep>::max()); }
373 
374  private:
375  rep __r;
376  };
377 
378  template<typename _Rep1, typename _Period1,
379  typename _Rep2, typename _Period2>
380  constexpr typename common_type<duration<_Rep1, _Period1>,
381  duration<_Rep2, _Period2>>::type
382  operator+(const duration<_Rep1, _Period1>& __lhs,
383  const duration<_Rep2, _Period2>& __rhs)
384  {
385  typedef duration<_Rep1, _Period1> __dur1;
386  typedef duration<_Rep2, _Period2> __dur2;
387  typedef typename common_type<__dur1,__dur2>::type __cd;
388  return __cd(__cd(__lhs).count() + __cd(__rhs).count());
389  }
390 
391  template<typename _Rep1, typename _Period1,
392  typename _Rep2, typename _Period2>
393  constexpr typename common_type<duration<_Rep1, _Period1>,
394  duration<_Rep2, _Period2>>::type
395  operator-(const duration<_Rep1, _Period1>& __lhs,
396  const duration<_Rep2, _Period2>& __rhs)
397  {
398  typedef duration<_Rep1, _Period1> __dur1;
399  typedef duration<_Rep2, _Period2> __dur2;
400  typedef typename common_type<__dur1,__dur2>::type __cd;
401  return __cd(__cd(__lhs).count() - __cd(__rhs).count());
402  }
403 
404  // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
405  // is implicitly convertible to it.
406  // _GLIBCXX_RESOLVE_LIB_DEFECTS
407  // 3050. Conversion specification problem in chrono::duration constructor
408  template<typename _Rep1, typename _Rep2, bool =
409  is_convertible<const _Rep2&,
410  typename common_type<_Rep1, _Rep2>::type>::value>
411  struct __common_rep_type { };
412 
413  template<typename _Rep1, typename _Rep2>
414  struct __common_rep_type<_Rep1, _Rep2, true>
415  { typedef typename common_type<_Rep1, _Rep2>::type type; };
416 
417  template<typename _Rep1, typename _Period, typename _Rep2>
418  constexpr
419  duration<typename __common_rep_type<_Rep1, _Rep2>::type, _Period>
420  operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
421  {
422  typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
423  __cd;
424  return __cd(__cd(__d).count() * __s);
425  }
426 
427  template<typename _Rep1, typename _Rep2, typename _Period>
428  constexpr
429  duration<typename __common_rep_type<_Rep2, _Rep1>::type, _Period>
430  operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
431  { return __d * __s; }
432 
433  template<typename _Rep1, typename _Period, typename _Rep2>
434  constexpr duration<typename __common_rep_type<_Rep1, typename
435  enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
436  operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
437  {
438  typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
439  __cd;
440  return __cd(__cd(__d).count() / __s);
441  }
442 
443  template<typename _Rep1, typename _Period1,
444  typename _Rep2, typename _Period2>
445  constexpr typename common_type<_Rep1, _Rep2>::type
446  operator/(const duration<_Rep1, _Period1>& __lhs,
447  const duration<_Rep2, _Period2>& __rhs)
448  {
449  typedef duration<_Rep1, _Period1> __dur1;
450  typedef duration<_Rep2, _Period2> __dur2;
451  typedef typename common_type<__dur1,__dur2>::type __cd;
452  return __cd(__lhs).count() / __cd(__rhs).count();
453  }
454 
455  // DR 934.
456  template<typename _Rep1, typename _Period, typename _Rep2>
457  constexpr duration<typename __common_rep_type<_Rep1, typename
458  enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
459  operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
460  {
461  typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
462  __cd;
463  return __cd(__cd(__d).count() % __s);
464  }
465 
466  template<typename _Rep1, typename _Period1,
467  typename _Rep2, typename _Period2>
468  constexpr typename common_type<duration<_Rep1, _Period1>,
469  duration<_Rep2, _Period2>>::type
470  operator%(const duration<_Rep1, _Period1>& __lhs,
471  const duration<_Rep2, _Period2>& __rhs)
472  {
473  typedef duration<_Rep1, _Period1> __dur1;
474  typedef duration<_Rep2, _Period2> __dur2;
475  typedef typename common_type<__dur1,__dur2>::type __cd;
476  return __cd(__cd(__lhs).count() % __cd(__rhs).count());
477  }
478 
479  // comparisons
480  template<typename _Rep1, typename _Period1,
481  typename _Rep2, typename _Period2>
482  constexpr bool
483  operator==(const duration<_Rep1, _Period1>& __lhs,
484  const duration<_Rep2, _Period2>& __rhs)
485  {
486  typedef duration<_Rep1, _Period1> __dur1;
487  typedef duration<_Rep2, _Period2> __dur2;
488  typedef typename common_type<__dur1,__dur2>::type __ct;
489  return __ct(__lhs).count() == __ct(__rhs).count();
490  }
491 
492  template<typename _Rep1, typename _Period1,
493  typename _Rep2, typename _Period2>
494  constexpr bool
495  operator<(const duration<_Rep1, _Period1>& __lhs,
496  const duration<_Rep2, _Period2>& __rhs)
497  {
498  typedef duration<_Rep1, _Period1> __dur1;
499  typedef duration<_Rep2, _Period2> __dur2;
500  typedef typename common_type<__dur1,__dur2>::type __ct;
501  return __ct(__lhs).count() < __ct(__rhs).count();
502  }
503 
504  template<typename _Rep1, typename _Period1,
505  typename _Rep2, typename _Period2>
506  constexpr bool
507  operator!=(const duration<_Rep1, _Period1>& __lhs,
508  const duration<_Rep2, _Period2>& __rhs)
509  { return !(__lhs == __rhs); }
510 
511  template<typename _Rep1, typename _Period1,
512  typename _Rep2, typename _Period2>
513  constexpr bool
514  operator<=(const duration<_Rep1, _Period1>& __lhs,
515  const duration<_Rep2, _Period2>& __rhs)
516  { return !(__rhs < __lhs); }
517 
518  template<typename _Rep1, typename _Period1,
519  typename _Rep2, typename _Period2>
520  constexpr bool
521  operator>(const duration<_Rep1, _Period1>& __lhs,
522  const duration<_Rep2, _Period2>& __rhs)
523  { return __rhs < __lhs; }
524 
525  template<typename _Rep1, typename _Period1,
526  typename _Rep2, typename _Period2>
527  constexpr bool
528  operator>=(const duration<_Rep1, _Period1>& __lhs,
529  const duration<_Rep2, _Period2>& __rhs)
530  { return !(__lhs < __rhs); }
531 
532  /// nanoseconds
534 
535  /// microseconds
537 
538  /// milliseconds
540 
541  /// seconds
543 
544  /// minutes
546 
547  /// hours
549 
550  /// time_point
551  template<typename _Clock, typename _Dur>
552  struct time_point
553  {
554  typedef _Clock clock;
555  typedef _Dur duration;
556  typedef typename duration::rep rep;
557  typedef typename duration::period period;
558 
559  constexpr time_point() : __d(duration::zero())
560  { }
561 
562  constexpr explicit time_point(const duration& __dur)
563  : __d(__dur)
564  { }
565 
566  // conversions
567  template<typename _Dur2,
568  typename = _Require<is_convertible<_Dur2, _Dur>>>
569  constexpr time_point(const time_point<clock, _Dur2>& __t)
570  : __d(__t.time_since_epoch())
571  { }
572 
573  // observer
574  constexpr duration
575  time_since_epoch() const
576  { return __d; }
577 
578  // arithmetic
579  time_point&
580  operator+=(const duration& __dur)
581  {
582  __d += __dur;
583  return *this;
584  }
585 
586  time_point&
587  operator-=(const duration& __dur)
588  {
589  __d -= __dur;
590  return *this;
591  }
592 
593  // special values
594  static constexpr time_point
595  min()
596  { return time_point(duration::min()); }
597 
598  static constexpr time_point
599  max()
600  { return time_point(duration::max()); }
601 
602  private:
603  duration __d;
604  };
605 
606  /// time_point_cast
607  template<typename _ToDur, typename _Clock, typename _Dur>
608  constexpr typename enable_if<__is_duration<_ToDur>::value,
609  time_point<_Clock, _ToDur>>::type
611  {
612  typedef time_point<_Clock, _ToDur> __time_point;
613  return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
614  }
615 
616  template<typename _Clock, typename _Dur1,
617  typename _Rep2, typename _Period2>
618  constexpr time_point<_Clock,
619  typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
620  operator+(const time_point<_Clock, _Dur1>& __lhs,
621  const duration<_Rep2, _Period2>& __rhs)
622  {
623  typedef duration<_Rep2, _Period2> __dur2;
624  typedef typename common_type<_Dur1,__dur2>::type __ct;
625  typedef time_point<_Clock, __ct> __time_point;
626  return __time_point(__lhs.time_since_epoch() + __rhs);
627  }
628 
629  template<typename _Rep1, typename _Period1,
630  typename _Clock, typename _Dur2>
631  constexpr time_point<_Clock,
632  typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
633  operator+(const duration<_Rep1, _Period1>& __lhs,
634  const time_point<_Clock, _Dur2>& __rhs)
635  {
636  typedef duration<_Rep1, _Period1> __dur1;
637  typedef typename common_type<__dur1,_Dur2>::type __ct;
638  typedef time_point<_Clock, __ct> __time_point;
639  return __time_point(__rhs.time_since_epoch() + __lhs);
640  }
641 
642  template<typename _Clock, typename _Dur1,
643  typename _Rep2, typename _Period2>
644  constexpr time_point<_Clock,
645  typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
646  operator-(const time_point<_Clock, _Dur1>& __lhs,
647  const duration<_Rep2, _Period2>& __rhs)
648  {
649  typedef duration<_Rep2, _Period2> __dur2;
650  typedef typename common_type<_Dur1,__dur2>::type __ct;
651  typedef time_point<_Clock, __ct> __time_point;
652  return __time_point(__lhs.time_since_epoch() -__rhs);
653  }
654 
655  template<typename _Clock, typename _Dur1, typename _Dur2>
656  constexpr typename common_type<_Dur1, _Dur2>::type
657  operator-(const time_point<_Clock, _Dur1>& __lhs,
658  const time_point<_Clock, _Dur2>& __rhs)
659  { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
660 
661  template<typename _Clock, typename _Dur1, typename _Dur2>
662  constexpr bool
663  operator==(const time_point<_Clock, _Dur1>& __lhs,
664  const time_point<_Clock, _Dur2>& __rhs)
665  { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
666 
667  template<typename _Clock, typename _Dur1, typename _Dur2>
668  constexpr bool
669  operator!=(const time_point<_Clock, _Dur1>& __lhs,
670  const time_point<_Clock, _Dur2>& __rhs)
671  { return !(__lhs == __rhs); }
672 
673  template<typename _Clock, typename _Dur1, typename _Dur2>
674  constexpr bool
675  operator<(const time_point<_Clock, _Dur1>& __lhs,
676  const time_point<_Clock, _Dur2>& __rhs)
677  { return __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
678 
679  template<typename _Clock, typename _Dur1, typename _Dur2>
680  constexpr bool
681  operator<=(const time_point<_Clock, _Dur1>& __lhs,
682  const time_point<_Clock, _Dur2>& __rhs)
683  { return !(__rhs < __lhs); }
684 
685  template<typename _Clock, typename _Dur1, typename _Dur2>
686  constexpr bool
687  operator>(const time_point<_Clock, _Dur1>& __lhs,
688  const time_point<_Clock, _Dur2>& __rhs)
689  { return __rhs < __lhs; }
690 
691  template<typename _Clock, typename _Dur1, typename _Dur2>
692  constexpr bool
693  operator>=(const time_point<_Clock, _Dur1>& __lhs,
694  const time_point<_Clock, _Dur2>& __rhs)
695  { return !(__lhs < __rhs); }
696 
697 
698  // Clocks.
699 
700  // Why nanosecond resolution as the default?
701  // Why have std::system_clock always count in the higest
702  // resolution (ie nanoseconds), even if on some OSes the low 3
703  // or 9 decimal digits will be always zero? This allows later
704  // implementations to change the system_clock::now()
705  // implementation any time to provide better resolution without
706  // changing function signature or units.
707 
708  // To support the (forward) evolution of the library's defined
709  // clocks, wrap inside inline namespace so that the current
710  // defintions of system_clock, steady_clock, and
711  // high_resolution_clock types are uniquely mangled. This way, new
712  // code can use the latests clocks, while the library can contain
713  // compatibility definitions for previous versions. At some
714  // point, when these clocks settle down, the inlined namespaces
715  // can be removed. XXX GLIBCXX_ABI Deprecated
716  inline namespace _V2 {
717 
718  /**
719  * @brief System clock.
720  *
721  * Time returned represents wall time from the system-wide clock.
722  */
724  {
726  typedef duration::rep rep;
727  typedef duration::period period;
729 
730  static_assert(system_clock::duration::min()
731  < system_clock::duration::zero(),
732  "a clock's minimum duration cannot be less than its epoch");
733 
734  static constexpr bool is_steady = false;
735 
736  static time_point
737  now() noexcept;
738 
739  // Map to C API
740  static std::time_t
741  to_time_t(const time_point& __t) noexcept
742  {
743  return std::time_t(duration_cast<chrono::seconds>
744  (__t.time_since_epoch()).count());
745  }
746 
747  static time_point
748  from_time_t(std::time_t __t) noexcept
749  {
752  (__from(chrono::seconds(__t)));
753  }
754  };
755 
756 
757  /**
758  * @brief Monotonic clock
759  *
760  * Time returned has the property of only increasing at a uniform rate.
761  */
763  {
765  typedef duration::rep rep;
766  typedef duration::period period;
768 
769  static constexpr bool is_steady = true;
770 
771  static time_point
772  now() noexcept;
773  };
774 
775 
776  /**
777  * @brief Highest-resolution clock
778  *
779  * This is the clock "with the shortest tick period." Alias to
780  * std::system_clock until higher-than-nanosecond definitions
781  * become feasible.
782  */
784 
785  } // end inline namespace _V2
786 
787  _GLIBCXX_END_NAMESPACE_VERSION
788  } // namespace chrono
789 
790 #if __cplusplus > 201103L
791 
792 #define __cpp_lib_chrono_udls 201304
793 
794  inline namespace literals
795  {
796  inline namespace chrono_literals
797  {
798  _GLIBCXX_BEGIN_NAMESPACE_VERSION
799 
800  template<typename _Rep, unsigned long long _Val>
801  struct _Checked_integral_constant
802  : integral_constant<_Rep, static_cast<_Rep>(_Val)>
803  {
804  static_assert(_Checked_integral_constant::value >= 0
805  && _Checked_integral_constant::value == _Val,
806  "literal value cannot be represented by duration type");
807  };
808 
809  template<typename _Dur, char... _Digits>
810  constexpr _Dur __check_overflow()
811  {
812  using _Val = __parse_int::_Parse_int<_Digits...>;
813  using _Rep = typename _Dur::rep;
814  // TODO: should be simply integral_constant<_Rep, _Val::value>
815  // but GCC doesn't reject narrowing conversions to _Rep.
816  using _CheckedVal = _Checked_integral_constant<_Rep, _Val::value>;
817  return _Dur{_CheckedVal::value};
818  }
819 
820  constexpr chrono::duration<long double, ratio<3600,1>>
821  operator""h(long double __hours)
822  { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
823 
824  template <char... _Digits>
825  constexpr chrono::hours
826  operator""h()
827  { return __check_overflow<chrono::hours, _Digits...>(); }
828 
829  constexpr chrono::duration<long double, ratio<60,1>>
830  operator""min(long double __mins)
831  { return chrono::duration<long double, ratio<60,1>>{__mins}; }
832 
833  template <char... _Digits>
834  constexpr chrono::minutes
835  operator""min()
836  { return __check_overflow<chrono::minutes, _Digits...>(); }
837 
838  constexpr chrono::duration<long double>
839  operator""s(long double __secs)
840  { return chrono::duration<long double>{__secs}; }
841 
842  template <char... _Digits>
843  constexpr chrono::seconds
844  operator""s()
845  { return __check_overflow<chrono::seconds, _Digits...>(); }
846 
847  constexpr chrono::duration<long double, milli>
848  operator""ms(long double __msecs)
849  { return chrono::duration<long double, milli>{__msecs}; }
850 
851  template <char... _Digits>
852  constexpr chrono::milliseconds
853  operator""ms()
854  { return __check_overflow<chrono::milliseconds, _Digits...>(); }
855 
856  constexpr chrono::duration<long double, micro>
857  operator""us(long double __usecs)
858  { return chrono::duration<long double, micro>{__usecs}; }
859 
860  template <char... _Digits>
861  constexpr chrono::microseconds
862  operator""us()
863  { return __check_overflow<chrono::microseconds, _Digits...>(); }
864 
865  constexpr chrono::duration<long double, nano>
866  operator""ns(long double __nsecs)
867  { return chrono::duration<long double, nano>{__nsecs}; }
868 
869  template <char... _Digits>
870  constexpr chrono::nanoseconds
871  operator""ns()
872  { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
873 
874  _GLIBCXX_END_NAMESPACE_VERSION
875  } // inline namespace chrono_literals
876  } // inline namespace literals
877 
878  namespace chrono
879  {
880  _GLIBCXX_BEGIN_NAMESPACE_VERSION
881 
882  using namespace literals::chrono_literals;
883 
884  _GLIBCXX_END_NAMESPACE_VERSION
885  } // namespace chrono
886 
887 #endif // __cplusplus > 201103L
888 
889  // @} group chrono
890 } // namespace std
891 
892 #endif //_GLIBCXX_USE_C99_STDINT_TR1
893 
894 #endif // C++11
895 
896 #endif //_GLIBCXX_CHRONO
_GLIBCXX14_CONSTEXPR const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:195
duration< int64_t > seconds
seconds
Definition: chrono:542
integral_constant
Definition: type_traits:69
complex< _Tp > operator/(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x divided by y.
Definition: complex:416
duration< int64_t, nano > nanoseconds
nanoseconds
Definition: chrono:533
duration< int64_t, ratio< 3600 > > hours
hours
Definition: chrono:548
constexpr enable_if< __is_duration< _ToDur >::value, _ToDur >::type duration_cast(const duration< _Rep, _Period > &__d)
duration_cast
Definition: chrono:194
complex< _Tp > operator+(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x plus y.
Definition: complex:326
duration_values
Definition: chrono:214
duration< int64_t, milli > milliseconds
milliseconds
Definition: chrono:539
duration< int64_t, ratio< 60 > > minutes
minutes
Definition: chrono:545
constexpr enable_if< __is_duration< _ToDur >::value, time_point< _Clock, _ToDur > >::type time_point_cast(const time_point< _Clock, _Dur > &__t)
time_point_cast
Definition: chrono:610
duration< int64_t, micro > microseconds
microseconds
Definition: chrono:536
duration
Definition: chrono:64
Monotonic clock.
Definition: chrono:762
_GLIBCXX14_CONSTEXPR const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:219
treat_as_floating_point
Definition: chrono:208
static constexpr _Tp lowest() noexcept
Definition: limits:330
typename __ratio_divide< _R1, _R2 >::type ratio_divide
ratio_divide
Definition: ratio:336
complex< _Tp > operator*(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x times y.
Definition: complex:386
is_floating_point
Definition: type_traits:350
time_point
Definition: chrono:67
Provides compile-time rational arithmetic.
Definition: ratio:263
complex< _Tp > operator-(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x minus y.
Definition: complex:356
static constexpr _Tp max() noexcept
Definition: limits:324