libstdc++-v3/include/std/condition_variable - gcc - Git at Google

 // <condition_variable> -*- C++ -*-

 // Copyright (C) 2008-2025 Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
 // terms of the GNU General Public License as published by the
 // Free Software Foundation; either version 3, or (at your option)
 // any later version.

 // This library is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 // GNU General Public License for more details.

 // Under Section 7 of GPL version 3, you are granted additional
 // permissions described in the GCC Runtime Library Exception, version
 // 3.1, as published by the Free Software Foundation.

 // You should have received a copy of the GNU General Public License and
 // a copy of the GCC Runtime Library Exception along with this program;
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.

 /** @file include/condition_variable
  *  This is a Standard C++ Library header.
  */

 #ifndef _GLIBCXX_CONDITION_VARIABLE
 #define _GLIBCXX_CONDITION_VARIABLE 1

 #ifdef _GLIBCXX_SYSHDR
 #pragma GCC system_header
 #endif

 #include <bits/requires_hosted.h> // threading primitive

 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else

 #include <bits/chrono.h>
 #include <bits/error_constants.h>
 #include <bits/std_mutex.h>
 #include <bits/unique_lock.h>
 #include <bits/alloc_traits.h>
 #include <bits/shared_ptr.h>
 #include <bits/cxxabi_forced.h>

 #if __cplusplus > 201703L
 # include <stop_token>
 #endif

 #if defined(_GLIBCXX_HAS_GTHREADS)

 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION

   /**
    * @defgroup condition_variables Condition Variables
    * @ingroup concurrency
    *
    * Classes for condition_variable support.
    * @{
    */

   /// cv_status
   enum class cv_status { no_timeout, timeout };

   /// condition_variable
   class condition_variable
   {
     using steady_clock = chrono::steady_clock;
     using system_clock = chrono::system_clock;
 #ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
     using __clock_t = steady_clock;
 #else
     using __clock_t = system_clock;
 #endif

     __condvar _M_cond;

   public:
     typedef __gthread_cond_t* 		native_handle_type;

     condition_variable() noexcept;
     ~condition_variable() noexcept;

     condition_variable(const condition_variable&) = delete;
     condition_variable& operator=(const condition_variable&) = delete;

     void
     notify_one() noexcept;

     void
     notify_all() noexcept;

     void
     wait(unique_lock<mutex>& __lock);

     template<typename _Predicate>
       void
       wait(unique_lock<mutex>& __lock, _Predicate __p)
       {
 	while (!__p())
 	  wait(__lock);
       }

 #ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
     template<typename _Duration>
       cv_status
       wait_until(unique_lock<mutex>& __lock,
 		 const chrono::time_point<steady_clock, _Duration>& __atime)
       { return __wait_until_impl(__lock, __atime); }
 #endif

     template<typename _Duration>
       cv_status
       wait_until(unique_lock<mutex>& __lock,
 		 const chrono::time_point<system_clock, _Duration>& __atime)
       { return __wait_until_impl(__lock, __atime); }

     template<typename _Clock, typename _Duration>
       cv_status
       wait_until(unique_lock<mutex>& __lock,
 		 const chrono::time_point<_Clock, _Duration>& __atime)
       {
 #if __cplusplus > 201703L
 	static_assert(chrono::is_clock_v<_Clock>);
 #endif
 	using __s_dur = typename __clock_t::duration;
 	const typename _Clock::time_point __c_entry = _Clock::now();
 	const __clock_t::time_point __s_entry = __clock_t::now();
 	const auto __delta = __atime - __c_entry;
 	const auto __s_atime = __s_entry +
 	  chrono::__detail::ceil<__s_dur>(__delta);

 	if (__wait_until_impl(__lock, __s_atime) == cv_status::no_timeout)
 	  return cv_status::no_timeout;
 	// We got a timeout when measured against __clock_t but
 	// we need to check against the caller-supplied clock
 	// to tell whether we should return a timeout.
 	if (_Clock::now() < __atime)
 	  return cv_status::no_timeout;
 	return cv_status::timeout;
       }

     template<typename _Clock, typename _Duration, typename _Predicate>
       bool
       wait_until(unique_lock<mutex>& __lock,
 		 const chrono::time_point<_Clock, _Duration>& __atime,
 		 _Predicate __p)
       {
 	while (!__p())
 	  if (wait_until(__lock, __atime) == cv_status::timeout)
 	    return __p();
 	return true;
       }

     template<typename _Rep, typename _Period>
       cv_status
       wait_for(unique_lock<mutex>& __lock,
 	       const chrono::duration<_Rep, _Period>& __rtime)
       {
 	using __dur = typename steady_clock::duration;
 	return wait_until(__lock,
 			  steady_clock::now() +
 			  chrono::__detail::ceil<__dur>(__rtime));
       }

     template<typename _Rep, typename _Period, typename _Predicate>
       bool
       wait_for(unique_lock<mutex>& __lock,
 	       const chrono::duration<_Rep, _Period>& __rtime,
 	       _Predicate __p)
       {
 	using __dur = typename steady_clock::duration;
 	return wait_until(__lock,
 			  steady_clock::now() +
 			  chrono::__detail::ceil<__dur>(__rtime),
 			  std::move(__p));
       }

     native_handle_type
     native_handle()
     { return _M_cond.native_handle(); }

   private:
 #ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
     template<typename _Dur>
       cv_status
       __wait_until_impl(unique_lock<mutex>& __lock,
 			const chrono::time_point<steady_clock, _Dur>& __atime)
       {
 	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
 	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

 	__gthread_time_t __ts =
 	  {
 	    static_cast<std::time_t>(__s.time_since_epoch().count()),
 	    static_cast<long>(__ns.count())
 	  };

 	_M_cond.wait_until(*__lock.mutex(), CLOCK_MONOTONIC, __ts);

 	return (steady_clock::now() < __atime
 		? cv_status::no_timeout : cv_status::timeout);
       }
 #endif

     template<typename _Dur>
       cv_status
       __wait_until_impl(unique_lock<mutex>& __lock,
 			const chrono::time_point<system_clock, _Dur>& __atime)
       {
 	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
 	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

 	__gthread_time_t __ts =
 	  {
 	    static_cast<std::time_t>(__s.time_since_epoch().count()),
 	    static_cast<long>(__ns.count())
 	  };

 	_M_cond.wait_until(*__lock.mutex(), __ts);

 	return (system_clock::now() < __atime
 		? cv_status::no_timeout : cv_status::timeout);
       }
   };

   void
   notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);

   struct __at_thread_exit_elt
   {
     __at_thread_exit_elt* _M_next;
     void (*_M_cb)(void*);
   };

 _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2)

   /// condition_variable_any
   // Like above, but mutex is not required to have try_lock.
   class condition_variable_any
   {
 #ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
     using __clock_t = chrono::steady_clock;
 #else
     using __clock_t = chrono::system_clock;
 #endif
     condition_variable			_M_cond;
     shared_ptr<mutex>			_M_mutex;

     // scoped unlock - unlocks in ctor, re-locks in dtor
     template<typename _Lock>
       struct _Unlock
       {
 	explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }

 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 	~_Unlock() noexcept(false)
 	{
 	  if (uncaught_exception())
 	    {
 	      __try
 	      { _M_lock.lock(); }
 	      __catch(const __cxxabiv1::__forced_unwind&)
 	      { __throw_exception_again; }
 	      __catch(...)
 	      { }
 	    }
 	  else
 	    _M_lock.lock();
 	}
 #pragma GCC diagnostic pop

 	_Unlock(const _Unlock&) = delete;
 	_Unlock& operator=(const _Unlock&) = delete;

 	_Lock& _M_lock;
       };

   public:
     condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { }
     ~condition_variable_any() = default;

     condition_variable_any(const condition_variable_any&) = delete;
     condition_variable_any& operator=(const condition_variable_any&) = delete;

     void
     notify_one() noexcept
     {
       lock_guard<mutex> __lock(*_M_mutex);
       _M_cond.notify_one();
     }

     void
     notify_all() noexcept
     {
       lock_guard<mutex> __lock(*_M_mutex);
       _M_cond.notify_all();
     }

     template<typename _Lock>
       void
       wait(_Lock& __lock)
       {
 	shared_ptr<mutex> __mutex = _M_mutex;
 	unique_lock<mutex> __my_lock(*__mutex);
 	_Unlock<_Lock> __unlock(__lock);
 	// *__mutex must be unlocked before re-locking __lock so move
 	// ownership of *__mutex lock to an object with shorter lifetime.
 	unique_lock<mutex> __my_lock2(std::move(__my_lock));
 	_M_cond.wait(__my_lock2);
       }


     template<typename _Lock, typename _Predicate>
       void
       wait(_Lock& __lock, _Predicate __p)
       {
 	while (!__p())
 	  wait(__lock);
       }

     template<typename _Lock, typename _Clock, typename _Duration>
       cv_status
       wait_until(_Lock& __lock,
 		 const chrono::time_point<_Clock, _Duration>& __atime)
       {
 	shared_ptr<mutex> __mutex = _M_mutex;
 	unique_lock<mutex> __my_lock(*__mutex);
 	_Unlock<_Lock> __unlock(__lock);
 	// *__mutex must be unlocked before re-locking __lock so move
 	// ownership of *__mutex lock to an object with shorter lifetime.
 	unique_lock<mutex> __my_lock2(std::move(__my_lock));
 	return _M_cond.wait_until(__my_lock2, __atime);
       }

     template<typename _Lock, typename _Clock,
 	     typename _Duration, typename _Predicate>
       bool
       wait_until(_Lock& __lock,
 		 const chrono::time_point<_Clock, _Duration>& __atime,
 		 _Predicate __p)
       {
 	while (!__p())
 	  if (wait_until(__lock, __atime) == cv_status::timeout)
 	    return __p();
 	return true;
       }

     template<typename _Lock, typename _Rep, typename _Period>
       cv_status
       wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
       { return wait_until(__lock, __clock_t::now() + __rtime); }

     template<typename _Lock, typename _Rep,
 	     typename _Period, typename _Predicate>
       bool
       wait_for(_Lock& __lock,
 	       const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }

 #ifdef __glibcxx_jthread
     template <class _Lock, class _Predicate>
     bool wait(_Lock& __lock,
               stop_token __stoken,
               _Predicate __p)
     {
       if (__stoken.stop_requested())
         {
           return __p();
         }

       std::stop_callback __cb(__stoken, [this] { notify_all(); });
       shared_ptr<mutex> __mutex = _M_mutex;
       while (!__p())
         {
           unique_lock<mutex> __my_lock(*__mutex);
           if (__stoken.stop_requested())
             {
               return false;
             }
           // *__mutex must be unlocked before re-locking __lock so move
           // ownership of *__mutex lock to an object with shorter lifetime.
           _Unlock<_Lock> __unlock(__lock);
           unique_lock<mutex> __my_lock2(std::move(__my_lock));
           _M_cond.wait(__my_lock2);
         }
       return true;
     }

     template <class _Lock, class _Clock, class _Duration, class _Predicate>
     bool wait_until(_Lock& __lock,
                     stop_token __stoken,
                     const chrono::time_point<_Clock, _Duration>& __abs_time,
                     _Predicate __p)
     {
       if (__stoken.stop_requested())
         {
           return __p();
         }

       std::stop_callback __cb(__stoken, [this] { notify_all(); });
       shared_ptr<mutex> __mutex = _M_mutex;
       while (!__p())
         {
           bool __stop;
           {
             unique_lock<mutex> __my_lock(*__mutex);
             if (__stoken.stop_requested())
               {
                 return false;
               }
             _Unlock<_Lock> __u(__lock);
             unique_lock<mutex> __my_lock2(std::move(__my_lock));
             const auto __status = _M_cond.wait_until(__my_lock2, __abs_time);
             __stop = (__status == std::cv_status::timeout) || __stoken.stop_requested();
           }
           if (__stop)
             {
               return __p();
             }
         }
       return true;
     }

     template <class _Lock, class _Rep, class _Period, class _Predicate>
     bool wait_for(_Lock& __lock,
                   stop_token __stoken,
                   const chrono::duration<_Rep, _Period>& __rel_time,
                   _Predicate __p)
     {
       auto __abst = std::chrono::steady_clock::now() + __rel_time;
       return wait_until(__lock,
                         std::move(__stoken),
                         __abst,
                         std::move(__p));
     }
 #endif
   };

 _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)

   /// @} group condition_variables
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace

 #endif // _GLIBCXX_HAS_GTHREADS
 #endif // C++11
 #endif // _GLIBCXX_CONDITION_VARIABLE
	// <condition_variable> -- C++ --

	// Copyright (C) 2008-2025 Free Software Foundation, Inc.
	//
	// This file is part of the GNU ISO C++ Library. This library is free
	// software; you can redistribute it and/or modify it under the
	// terms of the GNU General Public License as published by the
	// Free Software Foundation; either version 3, or (at your option)
	// any later version.

	// This library is distributed in the hope that it will be useful,
	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	// GNU General Public License for more details.

	// Under Section 7 of GPL version 3, you are granted additional
	// permissions described in the GCC Runtime Library Exception, version
	// 3.1, as published by the Free Software Foundation.

	// You should have received a copy of the GNU General Public License and
	// a copy of the GCC Runtime Library Exception along with this program;
	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
	// <http://www.gnu.org/licenses/>.

	/** @file include/condition_variable
	* This is a Standard C++ Library header.
	*/

	#ifndef _GLIBCXX_CONDITION_VARIABLE
	#define _GLIBCXX_CONDITION_VARIABLE 1

	#ifdef _GLIBCXX_SYSHDR
	#pragma GCC system_header
	#endif

	#include <bits/requires_hosted.h> // threading primitive

	#if __cplusplus < 201103L
	# include <bits/c++0x_warning.h>
	#else

	#include <bits/chrono.h>
	#include <bits/error_constants.h>
	#include <bits/std_mutex.h>
	#include <bits/unique_lock.h>
	#include <bits/alloc_traits.h>
	#include <bits/shared_ptr.h>
	#include <bits/cxxabi_forced.h>

	#if __cplusplus > 201703L
	# include <stop_token>
	#endif

	#if defined(_GLIBCXX_HAS_GTHREADS)

	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION

	/**
	* @defgroup condition_variables Condition Variables
	* @ingroup concurrency
	*
	* Classes for condition_variable support.
	* @{
	*/

	/// cv_status
	enum class cv_status { no_timeout, timeout };

	/// condition_variable
	class condition_variable
	{
	using steady_clock = chrono::steady_clock;
	using system_clock = chrono::system_clock;
	#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
	using __clock_t = steady_clock;
	#else
	using __clock_t = system_clock;
	#endif

	__condvar _M_cond;

	public:
	typedef __gthread_cond_t* native_handle_type;

	condition_variable() noexcept;
	~condition_variable() noexcept;

	condition_variable(const condition_variable&) = delete;
	condition_variable& operator=(const condition_variable&) = delete;

	void
	notify_one() noexcept;

	void
	notify_all() noexcept;

	void
	wait(unique_lock<mutex>& __lock);

	template<typename _Predicate>
	void
	wait(unique_lock<mutex>& __lock, _Predicate __p)
	{
	while (!__p())
	wait(__lock);
	}

	#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
	template<typename _Duration>
	cv_status
	wait_until(unique_lock<mutex>& __lock,
	const chrono::time_point<steady_clock, _Duration>& __atime)
	{ return __wait_until_impl(__lock, __atime); }
	#endif

	template<typename _Duration>
	cv_status
	wait_until(unique_lock<mutex>& __lock,
	const chrono::time_point<system_clock, _Duration>& __atime)
	{ return __wait_until_impl(__lock, __atime); }

	template<typename _Clock, typename _Duration>
	cv_status
	wait_until(unique_lock<mutex>& __lock,
	const chrono::time_point<_Clock, _Duration>& __atime)
	{
	#if __cplusplus > 201703L
	static_assert(chrono::is_clock_v<_Clock>);
	#endif
	using __s_dur = typename __clock_t::duration;
	const typename _Clock::time_point __c_entry = _Clock::now();
	const __clock_t::time_point __s_entry = __clock_t::now();
	const auto __delta = __atime - __c_entry;
	const auto __s_atime = __s_entry +
	chrono::__detail::ceil<__s_dur>(__delta);

	if (__wait_until_impl(__lock, __s_atime) == cv_status::no_timeout)
	return cv_status::no_timeout;
	// We got a timeout when measured against __clock_t but
	// we need to check against the caller-supplied clock
	// to tell whether we should return a timeout.
	if (_Clock::now() < __atime)
	return cv_status::no_timeout;
	return cv_status::timeout;
	}

	template<typename _Clock, typename _Duration, typename _Predicate>
	bool
	wait_until(unique_lock<mutex>& __lock,
	const chrono::time_point<_Clock, _Duration>& __atime,
	_Predicate __p)
	{
	while (!__p())
	if (wait_until(__lock, __atime) == cv_status::timeout)
	return __p();
	return true;
	}

	template<typename _Rep, typename _Period>
	cv_status
	wait_for(unique_lock<mutex>& __lock,
	const chrono::duration<_Rep, _Period>& __rtime)
	{
	using __dur = typename steady_clock::duration;
	return wait_until(__lock,
	steady_clock::now() +
	chrono::__detail::ceil<__dur>(__rtime));
	}

	template<typename _Rep, typename _Period, typename _Predicate>
	bool
	wait_for(unique_lock<mutex>& __lock,
	const chrono::duration<_Rep, _Period>& __rtime,
	_Predicate __p)
	{
	using __dur = typename steady_clock::duration;
	return wait_until(__lock,
	steady_clock::now() +
	chrono::__detail::ceil<__dur>(__rtime),
	std::move(__p));
	}

	native_handle_type
	native_handle()
	{ return _M_cond.native_handle(); }

	private:
	#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
	template<typename _Dur>
	cv_status
	__wait_until_impl(unique_lock<mutex>& __lock,
	const chrono::time_point<steady_clock, _Dur>& __atime)
	{
	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

	__gthread_time_t __ts =
	{
	static_cast<std::time_t>(__s.time_since_epoch().count()),
	static_cast<long>(__ns.count())
	};

	_M_cond.wait_until(*__lock.mutex(), CLOCK_MONOTONIC, __ts);

	return (steady_clock::now() < __atime
	? cv_status::no_timeout : cv_status::timeout);
	}
	#endif

	template<typename _Dur>
	cv_status
	__wait_until_impl(unique_lock<mutex>& __lock,
	const chrono::time_point<system_clock, _Dur>& __atime)
	{
	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

	__gthread_time_t __ts =
	{
	static_cast<std::time_t>(__s.time_since_epoch().count()),
	static_cast<long>(__ns.count())
	};

	_M_cond.wait_until(*__lock.mutex(), __ts);

	return (system_clock::now() < __atime
	? cv_status::no_timeout : cv_status::timeout);
	}
	};

	void
	notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);

	struct __at_thread_exit_elt
	{
	__at_thread_exit_elt* _M_next;
	void (_M_cb)(void);
	};

	_GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2)

	/// condition_variable_any
	// Like above, but mutex is not required to have try_lock.
	class condition_variable_any
	{
	#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
	using __clock_t = chrono::steady_clock;
	#else
	using __clock_t = chrono::system_clock;
	#endif
	condition_variable _M_cond;
	shared_ptr<mutex> _M_mutex;

	// scoped unlock - unlocks in ctor, re-locks in dtor
	template<typename _Lock>
	struct _Unlock
	{
	explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }

	#pragma GCC diagnostic push
	#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
	~_Unlock() noexcept(false)
	{
	if (uncaught_exception())
	{
	__try
	{ _M_lock.lock(); }
	__catch(const __cxxabiv1::__forced_unwind&)
	{ __throw_exception_again; }
	__catch(...)
	{ }
	}
	else
	_M_lock.lock();
	}
	#pragma GCC diagnostic pop

	_Unlock(const _Unlock&) = delete;
	_Unlock& operator=(const _Unlock&) = delete;

	_Lock& _M_lock;
	};

	public:
	condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { }
	~condition_variable_any() = default;

	condition_variable_any(const condition_variable_any&) = delete;
	condition_variable_any& operator=(const condition_variable_any&) = delete;

	void
	notify_one() noexcept
	{
	lock_guard<mutex> __lock(*_M_mutex);
	_M_cond.notify_one();
	}

	void
	notify_all() noexcept
	{
	lock_guard<mutex> __lock(*_M_mutex);
	_M_cond.notify_all();
	}

	template<typename _Lock>
	void
	wait(_Lock& __lock)
	{
	shared_ptr<mutex> __mutex = _M_mutex;
	unique_lock<mutex> __my_lock(*__mutex);
	_Unlock<_Lock> __unlock(__lock);
	// *__mutex must be unlocked before re-locking __lock so move
	// ownership of *__mutex lock to an object with shorter lifetime.
	unique_lock<mutex> __my_lock2(std::move(__my_lock));
	_M_cond.wait(__my_lock2);
	}


	template<typename _Lock, typename _Predicate>
	void
	wait(_Lock& __lock, _Predicate __p)
	{
	while (!__p())
	wait(__lock);
	}

	template<typename _Lock, typename _Clock, typename _Duration>
	cv_status
	wait_until(_Lock& __lock,
	const chrono::time_point<_Clock, _Duration>& __atime)
	{
	shared_ptr<mutex> __mutex = _M_mutex;
	unique_lock<mutex> __my_lock(*__mutex);
	_Unlock<_Lock> __unlock(__lock);
	// *__mutex must be unlocked before re-locking __lock so move
	// ownership of *__mutex lock to an object with shorter lifetime.
	unique_lock<mutex> __my_lock2(std::move(__my_lock));
	return _M_cond.wait_until(__my_lock2, __atime);
	}

	template<typename _Lock, typename _Clock,
	typename _Duration, typename _Predicate>
	bool
	wait_until(_Lock& __lock,
	const chrono::time_point<_Clock, _Duration>& __atime,
	_Predicate __p)
	{
	while (!__p())
	if (wait_until(__lock, __atime) == cv_status::timeout)
	return __p();
	return true;
	}

	template<typename _Lock, typename _Rep, typename _Period>
	cv_status
	wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
	{ return wait_until(__lock, __clock_t::now() + __rtime); }

	template<typename _Lock, typename _Rep,
	typename _Period, typename _Predicate>
	bool
	wait_for(_Lock& __lock,
	const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
	{ return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }

	#ifdef __glibcxx_jthread
	template <class _Lock, class _Predicate>
	bool wait(_Lock& __lock,
	stop_token __stoken,
	_Predicate __p)
	{
	if (__stoken.stop_requested())
	{
	return __p();
	}

	std::stop_callback __cb(__stoken, [this] { notify_all(); });
	shared_ptr<mutex> __mutex = _M_mutex;
	while (!__p())
	{
	unique_lock<mutex> __my_lock(*__mutex);
	if (__stoken.stop_requested())
	{
	return false;
	}
	// *__mutex must be unlocked before re-locking __lock so move
	// ownership of *__mutex lock to an object with shorter lifetime.
	_Unlock<_Lock> __unlock(__lock);
	unique_lock<mutex> __my_lock2(std::move(__my_lock));
	_M_cond.wait(__my_lock2);
	}
	return true;
	}

	template <class _Lock, class _Clock, class _Duration, class _Predicate>
	bool wait_until(_Lock& __lock,
	stop_token __stoken,
	const chrono::time_point<_Clock, _Duration>& __abs_time,
	_Predicate __p)
	{
	if (__stoken.stop_requested())
	{
	return __p();
	}

	std::stop_callback __cb(__stoken, [this] { notify_all(); });
	shared_ptr<mutex> __mutex = _M_mutex;
	while (!__p())
	{
	bool __stop;
	{
	unique_lock<mutex> __my_lock(*__mutex);
	if (__stoken.stop_requested())
	{
	return false;
	}
	_Unlock<_Lock> __u(__lock);
	unique_lock<mutex> __my_lock2(std::move(__my_lock));
	const auto __status = _M_cond.wait_until(__my_lock2, __abs_time);
	__stop = (__status == std::cv_status::timeout) \|\| __stoken.stop_requested();
	}
	if (__stop)
	{
	return __p();
	}
	}
	return true;
	}

	template <class _Lock, class _Rep, class _Period, class _Predicate>
	bool wait_for(_Lock& __lock,
	stop_token __stoken,
	const chrono::duration<_Rep, _Period>& __rel_time,
	_Predicate __p)
	{
	auto __abst = std::chrono::steady_clock::now() + __rel_time;
	return wait_until(__lock,
	std::move(__stoken),
	__abst,
	std::move(__p));
	}
	#endif
	};

	_GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)

	/// @} group condition_variables
	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace

	#endif // _GLIBCXX_HAS_GTHREADS
	#endif // C++11
	#endif // _GLIBCXX_CONDITION_VARIABLE