Where Online Learning is simpler!

The C and C++ Include Header Files

/usr/include/c++/13/bits/this_thread_sleep.h


$ cat -n /usr/include/c++/13/bits/this_thread_sleep.h

     1	// std::this_thread::sleep_for/until declarations -*- C++ -*-
     2	
     3	// Copyright (C) 2008-2023 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	
    43	namespace 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		    static_cast<std::time_t>(__s.count()),
    78		    static_cast<long>(__ns.count())
    79		  };
    80		while (::nanosleep(&__ts, &__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