libstdc++
this_thread_sleep.h
1 // std::this_thread::sleep_for/until declarations -*- C++ -*-
2 
3 // Copyright (C) 2008-2021 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 bits/std_thread_sleep.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{thread}
28  */
29 
30 #ifndef _GLIBCXX_THIS_THREAD_SLEEP_H
31 #define _GLIBCXX_THIS_THREAD_SLEEP_H 1
32 
33 #pragma GCC system_header
34 
35 #if __cplusplus >= 201103L
36 #include <bits/c++config.h>
37 
38 #include <chrono> // std::chrono::*
39 
40 #ifdef _GLIBCXX_USE_NANOSLEEP
41 # include <cerrno> // errno, EINTR
42 # include <time.h> // nanosleep
43 #endif
44 
45 namespace std _GLIBCXX_VISIBILITY(default)
46 {
47 _GLIBCXX_BEGIN_NAMESPACE_VERSION
48 
49  /** @addtogroup threads
50  * @{
51  */
52 
53  /** @namespace std::this_thread
54  * @brief ISO C++ 2011 namespace for interacting with the current thread
55  *
56  * C++11 30.3.2 [thread.thread.this] Namespace this_thread.
57  */
58  namespace this_thread
59  {
60 #ifndef _GLIBCXX_NO_SLEEP
61 
62 #ifndef _GLIBCXX_USE_NANOSLEEP
63  void
65 #endif
66 
67  /// this_thread::sleep_for
68  template<typename _Rep, typename _Period>
69  inline void
71  {
72  if (__rtime <= __rtime.zero())
73  return;
74  auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
75  auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
76 #ifdef _GLIBCXX_USE_NANOSLEEP
77  struct ::timespec __ts =
78  {
79  static_cast<std::time_t>(__s.count()),
80  static_cast<long>(__ns.count())
81  };
82  while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR)
83  { }
84 #else
85  __sleep_for(__s, __ns);
86 #endif
87  }
88 
89  /// this_thread::sleep_until
90  template<typename _Clock, typename _Duration>
91  inline void
93  {
94 #if __cplusplus > 201703L
95  static_assert(chrono::is_clock_v<_Clock>);
96 #endif
97  auto __now = _Clock::now();
98  if (_Clock::is_steady)
99  {
100  if (__now < __atime)
101  sleep_for(__atime - __now);
102  return;
103  }
104  while (__now < __atime)
105  {
106  sleep_for(__atime - __now);
107  __now = _Clock::now();
108  }
109  }
110  } // namespace this_thread
111 #endif // ! NO_SLEEP
112 
113  /// @}
114 
115 _GLIBCXX_END_NAMESPACE_VERSION
116 } // namespace
117 #endif // C++11
118 
119 #endif // _GLIBCXX_THIS_THREAD_SLEEP_H
void sleep_until(const chrono::time_point< _Clock, _Duration > &__atime)
this_thread::sleep_until
duration
Definition: chrono:71
void sleep_for(const chrono::duration< _Rep, _Period > &__rtime)
this_thread::sleep_for
time_point
Definition: chrono:74
duration< int64_t > seconds
seconds
Definition: chrono:825
duration< int64_t, nano > nanoseconds
nanoseconds
Definition: chrono:816
ISO C++ entities toplevel namespace is std.
constexpr __enable_if_is_duration< _ToDur > duration_cast(const duration< _Rep, _Period > &__d)
duration_cast
Definition: chrono:254