1// std::this_thread::sleep_for/until declarations -*- C++ -*-
2
3// Copyright (C) 2008-2024 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/this_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/chrono.h> // std::chrono::*
37
38#ifdef _GLIBCXX_USE_NANOSLEEP
39# include <cerrno> // errno, EINTR
40# include <time.h> // nanosleep
41#endif
42
43namespace std _GLIBCXX_VISIBILITY(default)
44{
45_GLIBCXX_BEGIN_NAMESPACE_VERSION
46
47 /** @addtogroup threads
48 * @{
49 */
50
51 /** @namespace std::this_thread
52 * @brief ISO C++ 2011 namespace for interacting with the current thread
53 *
54 * C++11 30.3.2 [thread.thread.this] Namespace this_thread.
55 */
56 namespace this_thread
57 {
58#ifndef _GLIBCXX_NO_SLEEP
59
60#ifndef _GLIBCXX_USE_NANOSLEEP
61 void
62 __sleep_for(chrono::seconds, chrono::nanoseconds);
63#endif
64
65 /// this_thread::sleep_for
66 template<typename _Rep, typename _Period>
67 inline void
68 sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
69 {
70 if (__rtime <= __rtime.zero())
71 return;
72 auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
73 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
74#ifdef _GLIBCXX_USE_NANOSLEEP
75 struct ::timespec __ts =
76 {
77 .tv_sec: static_cast<std::time_t>(__s.count()),
78 .tv_nsec: static_cast<long>(__ns.count())
79 };
80 while (::nanosleep(requested_time: &__ts, remaining: &__ts) == -1 && errno == EINTR)
81 { }
82#else
83 __sleep_for(__s, __ns);
84#endif
85 }
86
87 /// this_thread::sleep_until
88 template<typename _Clock, typename _Duration>
89 inline void
90 sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
91 {
92#if __cplusplus > 201703L
93 static_assert(chrono::is_clock_v<_Clock>);
94#endif
95 auto __now = _Clock::now();
96 if (_Clock::is_steady)
97 {
98 if (__now < __atime)
99 sleep_for(__atime - __now);
100 return;
101 }
102 while (__now < __atime)
103 {
104 sleep_for(__atime - __now);
105 __now = _Clock::now();
106 }
107 }
108#endif // ! NO_SLEEP
109 } // namespace this_thread
110
111 /// @}
112
113_GLIBCXX_END_NAMESPACE_VERSION
114} // namespace
115#endif // C++11
116
117#endif // _GLIBCXX_THIS_THREAD_SLEEP_H
118