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      1 // <thread> -*- C++ -*-
      2 
      3 // Copyright (C) 2008-2014 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 include/thread
     26  *  This is a Standard C++ Library header.
     27  */
     28 
     29 #ifndef _GLIBCXX_THREAD
     30 #define _GLIBCXX_THREAD 1
     31 
     32 #pragma GCC system_header
     33 
     34 #if __cplusplus < 201103L
     35 # include <bits/c++0x_warning.h>
     36 #else
     37 
     38 #include <chrono>
     39 #include <functional>
     40 #include <memory>
     41 #include <bits/functexcept.h>
     42 #include <bits/functional_hash.h>
     43 #include <bits/gthr.h>
     44 
     45 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
     46 
     47 namespace std _GLIBCXX_VISIBILITY(default)
     48 {
     49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     50 
     51   /**
     52    * @defgroup threads Threads
     53    * @ingroup concurrency
     54    *
     55    * Classes for thread support.
     56    * @{
     57    */
     58 
     59   /// thread
     60   class thread
     61   {
     62   public:
     63     typedef __gthread_t			native_handle_type;
     64     struct _Impl_base;
     65     typedef shared_ptr<_Impl_base>	__shared_base_type;
     66 
     67     /// thread::id
     68     class id
     69     {
     70       native_handle_type	_M_thread;
     71 
     72     public:
     73       id() noexcept : _M_thread() { }
     74 
     75       explicit
     76       id(native_handle_type __id) : _M_thread(__id) { }
     77 
     78     private:
     79       friend class thread;
     80       friend class hash<thread::id>;
     81 
     82       friend bool
     83       operator==(thread::id __x, thread::id __y) noexcept
     84       { return __gthread_equal(__x._M_thread, __y._M_thread); }
     85 
     86       friend bool
     87       operator<(thread::id __x, thread::id __y) noexcept
     88       { return __x._M_thread < __y._M_thread; }
     89 
     90       template<class _CharT, class _Traits>
     91 	friend basic_ostream<_CharT, _Traits>&
     92 	operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id);
     93     };
     94 
     95     // Simple base type that the templatized, derived class containing
     96     // an arbitrary functor can be converted to and called.
     97     struct _Impl_base
     98     {
     99       __shared_base_type	_M_this_ptr;
    100 
    101       inline virtual ~_Impl_base();
    102 
    103       virtual void _M_run() = 0;
    104     };
    105 
    106     template<typename _Callable>
    107       struct _Impl : public _Impl_base
    108       {
    109 	_Callable		_M_func;
    110 
    111 	_Impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f))
    112 	{ }
    113 
    114 	void
    115 	_M_run() { _M_func(); }
    116       };
    117 
    118   private:
    119     id				_M_id;
    120 
    121   public:
    122     thread() noexcept = default;
    123     // _GLIBCXX_RESOLVE_LIB_DEFECTS
    124     // 2097.  packaged_task constructors should be constrained
    125     thread(thread&) = delete;
    126     thread(const thread&) = delete;
    127 
    128     thread(thread&& __t) noexcept
    129     { swap(__t); }
    130 
    131     template<typename _Callable, typename... _Args>
    132       explicit 
    133       thread(_Callable&& __f, _Args&&... __args)
    134       {
    135         _M_start_thread(_M_make_routine(std::__bind_simple(
    136                 std::forward<_Callable>(__f),
    137                 std::forward<_Args>(__args)...)));
    138       }
    139 
    140     ~thread()
    141     {
    142       if (joinable())
    143 	std::terminate();
    144     }
    145 
    146     thread& operator=(const thread&) = delete;
    147 
    148     thread& operator=(thread&& __t) noexcept
    149     {
    150       if (joinable())
    151 	std::terminate();
    152       swap(__t);
    153       return *this;
    154     }
    155 
    156     void
    157     swap(thread& __t) noexcept
    158     { std::swap(_M_id, __t._M_id); }
    159 
    160     bool
    161     joinable() const noexcept
    162     { return !(_M_id == id()); }
    163 
    164     void
    165     join();
    166 
    167     void
    168     detach();
    169 
    170     thread::id
    171     get_id() const noexcept
    172     { return _M_id; }
    173 
    174     /** @pre thread is joinable
    175      */
    176     native_handle_type
    177     native_handle()
    178     { return _M_id._M_thread; }
    179 
    180     // Returns a value that hints at the number of hardware thread contexts.
    181     static unsigned int
    182     hardware_concurrency() noexcept;
    183 
    184   private:
    185     void
    186     _M_start_thread(__shared_base_type);
    187 
    188     template<typename _Callable>
    189       shared_ptr<_Impl<_Callable>>
    190       _M_make_routine(_Callable&& __f)
    191       {
    192 	// Create and allocate full data structure, not base.
    193 	return std::make_shared<_Impl<_Callable>>(std::forward<_Callable>(__f));
    194       }
    195   };
    196 
    197   inline thread::_Impl_base::~_Impl_base() = default;
    198 
    199   inline void
    200   swap(thread& __x, thread& __y) noexcept
    201   { __x.swap(__y); }
    202 
    203   inline bool
    204   operator!=(thread::id __x, thread::id __y) noexcept
    205   { return !(__x == __y); }
    206 
    207   inline bool
    208   operator<=(thread::id __x, thread::id __y) noexcept
    209   { return !(__y < __x); }
    210 
    211   inline bool
    212   operator>(thread::id __x, thread::id __y) noexcept
    213   { return __y < __x; }
    214 
    215   inline bool
    216   operator>=(thread::id __x, thread::id __y) noexcept
    217   { return !(__x < __y); }
    218 
    219   // DR 889.
    220   /// std::hash specialization for thread::id.
    221   template<>
    222     struct hash<thread::id>
    223     : public __hash_base<size_t, thread::id>
    224     {
    225       size_t
    226       operator()(const thread::id& __id) const noexcept
    227       { return std::_Hash_impl::hash(__id._M_thread); }
    228     };
    229 
    230   template<class _CharT, class _Traits>
    231     inline basic_ostream<_CharT, _Traits>&
    232     operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
    233     {
    234       if (__id == thread::id())
    235 	return __out << "thread::id of a non-executing thread";
    236       else
    237 	return __out << __id._M_thread;
    238     }
    239 
    240 _GLIBCXX_END_NAMESPACE_VERSION
    241 
    242   /** @namespace std::this_thread
    243    *  @brief ISO C++ 2011 entities sub-namespace for thread.
    244    *  30.3.2 Namespace this_thread.
    245    */
    246   namespace this_thread
    247   {
    248   _GLIBCXX_BEGIN_NAMESPACE_VERSION
    249 
    250     /// get_id
    251     inline thread::id
    252     get_id() noexcept { return thread::id(__gthread_self()); }
    253 
    254     /// yield
    255     inline void
    256     yield() noexcept
    257     {
    258 #ifdef _GLIBCXX_USE_SCHED_YIELD
    259       __gthread_yield();
    260 #endif
    261     }
    262 
    263     void
    264     __sleep_for(chrono::seconds, chrono::nanoseconds);
    265 
    266     /// sleep_for
    267     template<typename _Rep, typename _Period>
    268       inline void
    269       sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
    270       {
    271 	auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
    272 	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
    273 #ifdef _GLIBCXX_USE_NANOSLEEP
    274 	__gthread_time_t __ts =
    275 	  {
    276 	    static_cast<std::time_t>(__s.count()),
    277 	    static_cast<long>(__ns.count())
    278 	  };
    279 	::nanosleep(&__ts, 0);
    280 #else
    281 	__sleep_for(__s, __ns);
    282 #endif
    283       }
    284 
    285     /// sleep_until
    286     template<typename _Clock, typename _Duration>
    287       inline void
    288       sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
    289       { sleep_for(__atime - _Clock::now()); }
    290 
    291   _GLIBCXX_END_NAMESPACE_VERSION
    292   }
    293 
    294   // @} group threads
    295 
    296 } // namespace
    297 
    298 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
    299 
    300 #endif // C++11
    301 
    302 #endif // _GLIBCXX_THREAD
    303