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       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             : 
      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
      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       62109 :       sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
      71             :       {
      72       62109 :         if (__rtime <= __rtime.zero())
      73           0 :           return;
      74       62109 :         auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
      75       62109 :         auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
      76             : #ifdef _GLIBCXX_USE_NANOSLEEP
      77      124218 :         struct ::timespec __ts =
      78             :           {
      79       62109 :             static_cast<std::time_t>(__s.count()),
      80       62109 :             static_cast<long>(__ns.count())
      81             :           };
      82       62109 :         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       46999 :       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       46999 :         auto __now = _Clock::now();
      98             :         if (_Clock::is_steady)
      99             :           {
     100       46998 :             if (__now < __atime)
     101       46988 :               sleep_for(__atime - __now);
     102       46998 :             return;
     103             :           }
     104           2 :         while (__now < __atime)
     105             :           {
     106           1 :             sleep_for(__atime - __now);
     107           1 :             __now = _Clock::now();
     108             :           }
     109             :       }
     110             : #endif // ! NO_SLEEP
     111             :   } // namespace this_thread
     112             : 
     113             :   /// @}
     114             : 
     115             : _GLIBCXX_END_NAMESPACE_VERSION
     116             : } // namespace
     117             : #endif // C++11
     118             : 
     119             : #endif // _GLIBCXX_THIS_THREAD_SLEEP_H