<h2>Editing File: /usr/include/c++/8/thread</h2><form method='post'><textarea name='content' class='file-edit'>// &lt;thread&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/thread
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_THREAD
#define _GLIBCXX_THREAD 1

#pragma GCC system_header

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

#include &lt;chrono&gt;
#include &lt;memory&gt;
#include &lt;tuple&gt;
#include &lt;cerrno&gt;
#include &lt;bits/functexcept.h&gt;
#include &lt;bits/functional_hash.h&gt;
#include &lt;bits/invoke.h&gt;
#include &lt;bits/gthr.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 threads Threads
   * @ingroup concurrency
   *
   * Classes for thread support.
   * @{
   */

  /// thread
  class thread
  {
  public:
    // Abstract base class for types that wrap arbitrary functors to be
    // invoked in the new thread of execution.
    struct _State
    {
      virtual ~_State();
      virtual void _M_run() = 0;
    };
    using _State_ptr = unique_ptr&lt;_State&gt;;

    typedef __gthread_t			native_handle_type;

    /// thread::id
    class id
    {
      native_handle_type	_M_thread;

    public:
      id() noexcept : _M_thread() { }

      explicit
      id(native_handle_type __id) : _M_thread(__id) { }

    private:
      friend class thread;
      friend class hash&lt;thread::id&gt;;

      friend bool
      operator==(thread::id __x, thread::id __y) noexcept;

      friend bool
      operator&lt;(thread::id __x, thread::id __y) noexcept;

      template&lt;class _CharT, class _Traits&gt;
	friend basic_ostream&lt;_CharT, _Traits&gt;&amp;
	operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, thread::id __id);
    };

  private:
    id				_M_id;

    // _GLIBCXX_RESOLVE_LIB_DEFECTS
    // 2097.  packaged_task constructors should be constrained
    template&lt;typename _Tp&gt;
      using __not_same = __not_&lt;is_same&lt;
	typename remove_cv&lt;typename remove_reference&lt;_Tp&gt;::type&gt;::type,
	thread&gt;&gt;;

  public:
    thread() noexcept = default;

    template&lt;typename _Callable, typename... _Args,
	     typename = _Require&lt;__not_same&lt;_Callable&gt;&gt;&gt;
      explicit
      thread(_Callable&amp;&amp; __f, _Args&amp;&amp;... __args)
      {
	static_assert( __is_invocable&lt;typename decay&lt;_Callable&gt;::type,
				      typename decay&lt;_Args&gt;::type...&gt;::value,
	  &quot;std::thread arguments must be invocable after conversion to rvalues&quot;
	  );

#ifdef GTHR_ACTIVE_PROXY
	// Create a reference to pthread_create, not just the gthr weak symbol.
	auto __depend = reinterpret_cast&lt;void(*)()&gt;(&amp;pthread_create);
#else
	auto __depend = nullptr;
#endif
        _M_start_thread(_S_make_state(
	      __make_invoker(std::forward&lt;_Callable&gt;(__f),
			     std::forward&lt;_Args&gt;(__args)...)),
	    __depend);
      }

    ~thread()
    {
      if (joinable())
	std::terminate();
    }

    thread(const thread&amp;) = delete;

    thread(thread&amp;&amp; __t) noexcept
    { swap(__t); }

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

    thread&amp; operator=(thread&amp;&amp; __t) noexcept
    {
      if (joinable())
	std::terminate();
      swap(__t);
      return *this;
    }

    void
    swap(thread&amp; __t) noexcept
    { std::swap(_M_id, __t._M_id); }

    bool
    joinable() const noexcept
    { return !(_M_id == id()); }

    void
    join();

    void
    detach();

    thread::id
    get_id() const noexcept
    { return _M_id; }

    /** @pre thread is joinable
     */
    native_handle_type
    native_handle()
    { return _M_id._M_thread; }

    // Returns a value that hints at the number of hardware thread contexts.
    static unsigned int
    hardware_concurrency() noexcept;

  private:
    template&lt;typename _Callable&gt;
      struct _State_impl : public _State
      {
	_Callable		_M_func;

	_State_impl(_Callable&amp;&amp; __f) : _M_func(std::forward&lt;_Callable&gt;(__f))
	{ }

	void
	_M_run() { _M_func(); }
      };

    void
    _M_start_thread(_State_ptr, void (*)());

    template&lt;typename _Callable&gt;
      static _State_ptr
      _S_make_state(_Callable&amp;&amp; __f)
      {
	using _Impl = _State_impl&lt;_Callable&gt;;
	return _State_ptr{new _Impl{std::forward&lt;_Callable&gt;(__f)}};
      }
#if _GLIBCXX_THREAD_ABI_COMPAT
  public:
    struct _Impl_base;
    typedef shared_ptr&lt;_Impl_base&gt;	__shared_base_type;
    struct _Impl_base
    {
      __shared_base_type	_M_this_ptr;
      virtual ~_Impl_base() = default;
      virtual void _M_run() = 0;
    };

  private:
    void
    _M_start_thread(__shared_base_type, void (*)());

    void
    _M_start_thread(__shared_base_type);
#endif

  private:
    // A call wrapper that does INVOKE(forwarded tuple elements...)
    template&lt;typename _Tuple&gt;
      struct _Invoker
      {
	_Tuple _M_t;

	template&lt;size_t _Index&gt;
	  static __tuple_element_t&lt;_Index, _Tuple&gt;&amp;&amp;
	  _S_declval();

	template&lt;size_t... _Ind&gt;
	  auto
	  _M_invoke(_Index_tuple&lt;_Ind...&gt;)
	  noexcept(noexcept(std::__invoke(_S_declval&lt;_Ind&gt;()...)))
	  -&gt; decltype(std::__invoke(_S_declval&lt;_Ind&gt;()...))
	  { return std::__invoke(std::get&lt;_Ind&gt;(std::move(_M_t))...); }

	using _Indices
	  = typename _Build_index_tuple&lt;tuple_size&lt;_Tuple&gt;::value&gt;::__type;

	auto
	operator()()
	noexcept(noexcept(std::declval&lt;_Invoker&amp;&gt;()._M_invoke(_Indices())))
	-&gt; decltype(std::declval&lt;_Invoker&amp;&gt;()._M_invoke(_Indices()))
	{ return _M_invoke(_Indices()); }
      };

    template&lt;typename... _Tp&gt;
      using __decayed_tuple = tuple&lt;typename std::decay&lt;_Tp&gt;::type...&gt;;

  public:
    // Returns a call wrapper that stores
    // tuple{DECAY_COPY(__callable), DECAY_COPY(__args)...}.
    template&lt;typename _Callable, typename... _Args&gt;
      static _Invoker&lt;__decayed_tuple&lt;_Callable, _Args...&gt;&gt;
      __make_invoker(_Callable&amp;&amp; __callable, _Args&amp;&amp;... __args)
      {
	return { __decayed_tuple&lt;_Callable, _Args...&gt;{
	    std::forward&lt;_Callable&gt;(__callable), std::forward&lt;_Args&gt;(__args)...
	} };
      }
  };

  inline void
  swap(thread&amp; __x, thread&amp; __y) noexcept
  { __x.swap(__y); }

  inline bool
  operator==(thread::id __x, thread::id __y) noexcept
  {
    // pthread_equal is undefined if either thread ID is not valid, so we
    // can't safely use __gthread_equal on default-constructed values (nor
    // the non-zero value returned by this_thread::get_id() for
    // single-threaded programs using GNU libc). Assume EqualityComparable.
    return __x._M_thread == __y._M_thread;
  }

  inline bool
  operator!=(thread::id __x, thread::id __y) noexcept
  { return !(__x == __y); }

  inline bool
  operator&lt;(thread::id __x, thread::id __y) noexcept
  {
    // Pthreads doesn't define any way to do this, so we just have to
    // assume native_handle_type is LessThanComparable.
    return __x._M_thread &lt; __y._M_thread;
  }

  inline bool
  operator&lt;=(thread::id __x, thread::id __y) noexcept
  { return !(__y &lt; __x); }

  inline bool
  operator&gt;(thread::id __x, thread::id __y) noexcept
  { return __y &lt; __x; }

  inline bool
  operator&gt;=(thread::id __x, thread::id __y) noexcept
  { return !(__x &lt; __y); }

  // DR 889.
  /// std::hash specialization for thread::id.
  template&lt;&gt;
    struct hash&lt;thread::id&gt;
    : public __hash_base&lt;size_t, thread::id&gt;
    {
      size_t
      operator()(const thread::id&amp; __id) const noexcept
      { return std::_Hash_impl::hash(__id._M_thread); }
    };

  template&lt;class _CharT, class _Traits&gt;
    inline basic_ostream&lt;_CharT, _Traits&gt;&amp;
    operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, thread::id __id)
    {
      if (__id == thread::id())
	return __out &lt;&lt; &quot;thread::id of a non-executing thread&quot;;
      else
	return __out &lt;&lt; __id._M_thread;
    }

  /** @namespace std::this_thread
   *  @brief ISO C++ 2011 entities sub-namespace for thread.
   *  30.3.2 Namespace this_thread.
   */
  namespace this_thread
  {
    /// get_id
    inline thread::id
    get_id() noexcept
    {
#ifdef __GLIBC__
      // For the GNU C library pthread_self() is usable without linking to
      // libpthread.so but returns 0, so we cannot use it in single-threaded
      // programs, because this_thread::get_id() != thread::id{} must be true.
      // We know that pthread_t is an integral type in the GNU C library.
      if (!__gthread_active_p())
	return thread::id(1);
#endif
      return thread::id(__gthread_self());
    }

    /// yield
    inline void
    yield() noexcept
    {
#ifdef _GLIBCXX_USE_SCHED_YIELD
      __gthread_yield();
#endif
    }

    void
    __sleep_for(chrono::seconds, chrono::nanoseconds);

    /// sleep_for
    template&lt;typename _Rep, typename _Period&gt;
      inline void
      sleep_for(const chrono::duration&lt;_Rep, _Period&gt;&amp; __rtime)
      {
	if (__rtime &lt;= __rtime.zero())
	  return;
	auto __s = chrono::duration_cast&lt;chrono::seconds&gt;(__rtime);
	auto __ns = chrono::duration_cast&lt;chrono::nanoseconds&gt;(__rtime - __s);
#ifdef _GLIBCXX_USE_NANOSLEEP
	__gthread_time_t __ts =
	  {
	    static_cast&lt;std::time_t&gt;(__s.count()),
	    static_cast&lt;long&gt;(__ns.count())
	  };
	while (::nanosleep(&amp;__ts, &amp;__ts) == -1 &amp;&amp; errno == EINTR)
	  { }
#else
	__sleep_for(__s, __ns);
#endif
      }

    /// sleep_until
    template&lt;typename _Clock, typename _Duration&gt;
      inline void
      sleep_until(const chrono::time_point&lt;_Clock, _Duration&gt;&amp; __atime)
      {
	auto __now = _Clock::now();
	if (_Clock::is_steady)
	  {
	    if (__now &lt; __atime)
	      sleep_for(__atime - __now);
	    return;
	  }
	while (__now &lt; __atime)
	  {
	    sleep_for(__atime - __now);
	    __now = _Clock::now();
	  }
      }
  }

  // @} group threads

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

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

#endif // C++11

#endif // _GLIBCXX_THREAD
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