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/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/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
45namespace 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
64 __sleep_for(chrono::seconds, chrono::nanoseconds);
65#endif
66
67 /// this_thread::sleep_for
68 template<typename _Rep, typename _Period>
69 inline void
70 sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
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
92 sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
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
120