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The C and C++ Include Header Files

/usr/include/c++/11/bits/this_thread_sleep.h


$ cat -n /usr/include/c++/11/bits/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/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	      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	#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