1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___THREAD_THIS_THREAD_H 11 #define _LIBCPP___THREAD_THIS_THREAD_H 12 13 #include <__chrono/duration.h> 14 #include <__chrono/steady_clock.h> 15 #include <__chrono/time_point.h> 16 #include <__condition_variable/condition_variable.h> 17 #include <__config> 18 #include <__mutex/mutex.h> 19 #include <__mutex/unique_lock.h> 20 #include <__thread/support.h> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 # pragma GCC system_header 24 #endif 25 26 _LIBCPP_PUSH_MACROS 27 #include <__undef_macros> 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 namespace this_thread { 32 33 #if _LIBCPP_HAS_THREADS 34 35 _LIBCPP_EXPORTED_FROM_ABI void sleep_for(const chrono::nanoseconds& __ns); 36 37 template <class _Rep, class _Period> 38 _LIBCPP_HIDE_FROM_ABI void sleep_for(const chrono::duration<_Rep, _Period>& __d) { 39 if (__d > chrono::duration<_Rep, _Period>::zero()) { 40 // The standard guarantees a 64bit signed integer resolution for nanoseconds, 41 // so use INT64_MAX / 1e9 as cut-off point. Use a constant to avoid <climits> 42 // and issues with long double folding on PowerPC with GCC. 43 _LIBCPP_CONSTEXPR chrono::duration<long double> __max = chrono::duration<long double>(9223372036.0L); 44 chrono::nanoseconds __ns; 45 if (__d < __max) { 46 __ns = chrono::duration_cast<chrono::nanoseconds>(__d); 47 if (__ns < __d) 48 ++__ns; 49 } else 50 __ns = chrono::nanoseconds::max(); 51 this_thread::sleep_for(__ns); 52 } 53 } 54 55 template <class _Clock, class _Duration> 56 _LIBCPP_HIDE_FROM_ABI void sleep_until(const chrono::time_point<_Clock, _Duration>& __t) { 57 mutex __mut; 58 condition_variable __cv; 59 unique_lock<mutex> __lk(__mut); 60 while (_Clock::now() < __t) 61 __cv.wait_until(__lk, __t); 62 } 63 64 template <class _Duration> 65 inline _LIBCPP_HIDE_FROM_ABI void sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t) { 66 this_thread::sleep_for(__t - chrono::steady_clock::now()); 67 } 68 69 inline _LIBCPP_HIDE_FROM_ABI void yield() _NOEXCEPT { __libcpp_thread_yield(); } 70 71 #endif // _LIBCPP_HAS_THREADS 72 73 } // namespace this_thread 74 75 _LIBCPP_END_NAMESPACE_STD 76 77 _LIBCPP_POP_MACROS 78 79 #endif // _LIBCPP___THREAD_THIS_THREAD_H 80