<h2>Editing File: /usr/include/c++/8/condition_variable</h2><form method='post'><textarea name='content' class='file-edit'>// &lt;condition_variable&gt; -*- C++ -*-

// Copyright (C) 2008-2018 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
// &lt;http://www.gnu.org/licenses/&gt;.

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

#ifndef _GLIBCXX_CONDITION_VARIABLE
#define _GLIBCXX_CONDITION_VARIABLE 1

#pragma GCC system_header

#if __cplusplus &lt; 201103L
# include &lt;bits/c++0x_warning.h&gt;
#else

#include &lt;chrono&gt;
#include &lt;bits/std_mutex.h&gt;
#include &lt;ext/concurrence.h&gt;
#include &lt;bits/alloc_traits.h&gt;
#include &lt;bits/allocator.h&gt;
#include &lt;bits/unique_ptr.h&gt;
#include &lt;bits/shared_ptr.h&gt;
#include &lt;bits/cxxabi_forced.h&gt;

#if defined(_GLIBCXX_HAS_GTHREADS) &amp;&amp; defined(_GLIBCXX_USE_C99_STDINT_TR1)

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
  {
    typedef chrono::system_clock	__clock_t;
    typedef __gthread_cond_t		__native_type;

#ifdef __GTHREAD_COND_INIT
    __native_type			_M_cond = __GTHREAD_COND_INIT;
#else
    __native_type			_M_cond;
#endif

  public:
    typedef __native_type* 		native_handle_type;

    condition_variable() noexcept;
    ~condition_variable() noexcept;

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

    void
    notify_one() noexcept;

    void
    notify_all() noexcept;

    void
    wait(unique_lock&lt;mutex&gt;&amp; __lock) noexcept;

    template&lt;typename _Predicate&gt;
      void
      wait(unique_lock&lt;mutex&gt;&amp; __lock, _Predicate __p)
      {
	while (!__p())
	  wait(__lock);
      }

    template&lt;typename _Duration&gt;
      cv_status
      wait_until(unique_lock&lt;mutex&gt;&amp; __lock,
		 const chrono::time_point&lt;__clock_t, _Duration&gt;&amp; __atime)
      { return __wait_until_impl(__lock, __atime); }

    template&lt;typename _Clock, typename _Duration&gt;
      cv_status
      wait_until(unique_lock&lt;mutex&gt;&amp; __lock,
		 const chrono::time_point&lt;_Clock, _Duration&gt;&amp; __atime)
      {
	// DR 887 - Sync unknown clock to known clock.
	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 + __delta;

	return __wait_until_impl(__lock, __s_atime);
      }

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

    template&lt;typename _Rep, typename _Period&gt;
      cv_status
      wait_for(unique_lock&lt;mutex&gt;&amp; __lock,
	       const chrono::duration&lt;_Rep, _Period&gt;&amp; __rtime)
      {
	using __dur = typename __clock_t::duration;
	auto __reltime = chrono::duration_cast&lt;__dur&gt;(__rtime);
	if (__reltime &lt; __rtime)
	  ++__reltime;
	return wait_until(__lock, __clock_t::now() + __reltime);
      }

    template&lt;typename _Rep, typename _Period, typename _Predicate&gt;
      bool
      wait_for(unique_lock&lt;mutex&gt;&amp; __lock,
	       const chrono::duration&lt;_Rep, _Period&gt;&amp; __rtime,
	       _Predicate __p)
      {
	using __dur = typename __clock_t::duration;
	auto __reltime = chrono::duration_cast&lt;__dur&gt;(__rtime);
	if (__reltime &lt; __rtime)
	  ++__reltime;
	return wait_until(__lock, __clock_t::now() + __reltime, std::move(__p));
      }

    native_handle_type
    native_handle()
    { return &amp;_M_cond; }

  private:
    template&lt;typename _Dur&gt;
      cv_status
      __wait_until_impl(unique_lock&lt;mutex&gt;&amp; __lock,
			const chrono::time_point&lt;__clock_t, _Dur&gt;&amp; __atime)
      {
	auto __s = chrono::time_point_cast&lt;chrono::seconds&gt;(__atime);
	auto __ns = chrono::duration_cast&lt;chrono::nanoseconds&gt;(__atime - __s);

	__gthread_time_t __ts =
	  {
	    static_cast&lt;std::time_t&gt;(__s.time_since_epoch().count()),
	    static_cast&lt;long&gt;(__ns.count())
	  };

	__gthread_cond_timedwait(&amp;_M_cond, __lock.mutex()-&gt;native_handle(),
				 &amp;__ts);

	return (__clock_t::now() &lt; __atime
		? cv_status::no_timeout : cv_status::timeout);
      }
  };

  void
  notify_all_at_thread_exit(condition_variable&amp;, unique_lock&lt;mutex&gt;);

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

  inline namespace _V2 {

  /// condition_variable_any
  // Like above, but mutex is not required to have try_lock.
  class condition_variable_any
  {
    typedef chrono::system_clock	__clock_t;
    condition_variable			_M_cond;
    shared_ptr&lt;mutex&gt;			_M_mutex;

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

	~_Unlock() noexcept(false)
	{
	  if (uncaught_exception())
	    {
	      __try
	      { _M_lock.lock(); }
	      __catch(const __cxxabiv1::__forced_unwind&amp;)
	      { __throw_exception_again; }
	      __catch(...)
	      { }
	    }
	  else
	    _M_lock.lock();
	}

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

	_Lock&amp; _M_lock;
      };

  public:
    condition_variable_any() : _M_mutex(std::make_shared&lt;mutex&gt;()) { }
    ~condition_variable_any() = default;

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

    void
    notify_one() noexcept
    {
      lock_guard&lt;mutex&gt; __lock(*_M_mutex);
      _M_cond.notify_one();
    }

    void
    notify_all() noexcept
    {
      lock_guard&lt;mutex&gt; __lock(*_M_mutex);
      _M_cond.notify_all();
    }

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


    template&lt;typename _Lock, typename _Predicate&gt;
      void
      wait(_Lock&amp; __lock, _Predicate __p)
      {
	while (!__p())
	  wait(__lock);
      }

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

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

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

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

  } // end inline namespace

  // @} group condition_variables
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif // _GLIBCXX_HAS_GTHREADS &amp;&amp; _GLIBCXX_USE_C99_STDINT_TR1

#endif // C++11

#endif // _GLIBCXX_CONDITION_VARIABLE
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