LCOV - code coverage report
Current view: top level - usr/include/c++/7 - thread (source / functions) Hit Total Coverage
Test: coverage.info Lines: 8 9 88.9 %
Date: 2020-10-15 20:26:03 Functions: 1 1 100.0 %

          Line data    Source code
       1             : // <thread> -*- C++ -*-
       2             : 
       3             : // Copyright (C) 2008-2017 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 <memory>
      40             : #include <tuple>
      41             : #include <cerrno>
      42             : #include <bits/functexcept.h>
      43             : #include <bits/functional_hash.h>
      44             : #include <bits/invoke.h>
      45             : #include <bits/gthr.h>
      46             : 
      47             : #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
      48             : 
      49             : namespace std _GLIBCXX_VISIBILITY(default)
      50             : {
      51             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      52             : 
      53             :   /**
      54             :    * @defgroup threads Threads
      55             :    * @ingroup concurrency
      56             :    *
      57             :    * Classes for thread support.
      58             :    * @{
      59             :    */
      60             : 
      61             :   /// thread
      62             :   class thread
      63             :   {
      64             :   public:
      65             :     // Abstract base class for types that wrap arbitrary functors to be
      66             :     // invoked in the new thread of execution.
      67             :     struct _State
      68             :     {
      69             :       virtual ~_State();
      70             :       virtual void _M_run() = 0;
      71             :     };
      72             :     using _State_ptr = unique_ptr<_State>;
      73             : 
      74             :     typedef __gthread_t                 native_handle_type;
      75             : 
      76             :     /// thread::id
      77             :     class id
      78             :     {
      79             :       native_handle_type        _M_thread;
      80             : 
      81             :     public:
      82             :       id() noexcept : _M_thread() { }
      83             : 
      84             :       explicit
      85             :       id(native_handle_type __id) : _M_thread(__id) { }
      86             : 
      87             :     private:
      88             :       friend class thread;
      89             :       friend class hash<thread::id>;
      90             : 
      91             :       friend bool
      92             :       operator==(thread::id __x, thread::id __y) noexcept;
      93             : 
      94             :       friend bool
      95             :       operator<(thread::id __x, thread::id __y) noexcept;
      96             : 
      97             :       template<class _CharT, class _Traits>
      98             :         friend basic_ostream<_CharT, _Traits>&
      99             :         operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id);
     100             :     };
     101             : 
     102             :   private:
     103             :     id                          _M_id;
     104             : 
     105             :   public:
     106             :     thread() noexcept = default;
     107             :     // _GLIBCXX_RESOLVE_LIB_DEFECTS
     108             :     // 2097.  packaged_task constructors should be constrained
     109             :     thread(thread&) = delete;
     110             :     thread(const thread&) = delete;
     111             :     thread(const thread&&) = delete;
     112             : 
     113             :     thread(thread&& __t) noexcept
     114             :     { swap(__t); }
     115             : 
     116             :     template<typename _Callable, typename... _Args>
     117             :       explicit
     118             :       thread(_Callable&& __f, _Args&&... __args)
     119             :       {
     120             : #ifdef GTHR_ACTIVE_PROXY
     121             :         // Create a reference to pthread_create, not just the gthr weak symbol.
     122             :         auto __depend = reinterpret_cast<void(*)()>(&pthread_create);
     123             : #else
     124             :         auto __depend = nullptr;
     125             : #endif
     126             :         _M_start_thread(_S_make_state(
     127             :               __make_invoker(std::forward<_Callable>(__f),
     128             :                              std::forward<_Args>(__args)...)),
     129             :             __depend);
     130             :       }
     131             : 
     132             :     ~thread()
     133             :     {
     134             :       if (joinable())
     135             :         std::terminate();
     136             :     }
     137             : 
     138             :     thread& operator=(const thread&) = delete;
     139             : 
     140             :     thread& operator=(thread&& __t) noexcept
     141             :     {
     142             :       if (joinable())
     143             :         std::terminate();
     144             :       swap(__t);
     145             :       return *this;
     146             :     }
     147             : 
     148             :     void
     149             :     swap(thread& __t) noexcept
     150             :     { std::swap(_M_id, __t._M_id); }
     151             : 
     152             :     bool
     153             :     joinable() const noexcept
     154             :     { return !(_M_id == id()); }
     155             : 
     156             :     void
     157             :     join();
     158             : 
     159             :     void
     160             :     detach();
     161             : 
     162             :     thread::id
     163             :     get_id() const noexcept
     164             :     { return _M_id; }
     165             : 
     166             :     /** @pre thread is joinable
     167             :      */
     168             :     native_handle_type
     169             :     native_handle()
     170             :     { return _M_id._M_thread; }
     171             : 
     172             :     // Returns a value that hints at the number of hardware thread contexts.
     173             :     static unsigned int
     174             :     hardware_concurrency() noexcept;
     175             : 
     176             :   private:
     177             :     template<typename _Callable>
     178             :       struct _State_impl : public _State
     179             :       {
     180             :         _Callable               _M_func;
     181             : 
     182             :         _State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f))
     183             :         { }
     184             : 
     185             :         void
     186             :         _M_run() { _M_func(); }
     187             :       };
     188             : 
     189             :     void
     190             :     _M_start_thread(_State_ptr, void (*)());
     191             : 
     192             :     template<typename _Callable>
     193             :       static _State_ptr
     194             :       _S_make_state(_Callable&& __f)
     195             :       {
     196             :         using _Impl = _State_impl<_Callable>;
     197             :         return _State_ptr{new _Impl{std::forward<_Callable>(__f)}};
     198             :       }
     199             : #if _GLIBCXX_THREAD_ABI_COMPAT
     200             :   public:
     201             :     struct _Impl_base;
     202             :     typedef shared_ptr<_Impl_base>        __shared_base_type;
     203             :     struct _Impl_base
     204             :     {
     205             :       __shared_base_type        _M_this_ptr;
     206             :       virtual ~_Impl_base() = default;
     207             :       virtual void _M_run() = 0;
     208             :     };
     209             : 
     210             :   private:
     211             :     void
     212             :     _M_start_thread(__shared_base_type, void (*)());
     213             : 
     214             :     void
     215             :     _M_start_thread(__shared_base_type);
     216             : #endif
     217             : 
     218             :   private:
     219             :     // A call wrapper that does INVOKE(forwarded tuple elements...)
     220             :     template<typename _Tuple>
     221             :       struct _Invoker
     222             :       {
     223             :         _Tuple _M_t;
     224             : 
     225             :         template<size_t _Index>
     226             :           static __tuple_element_t<_Index, _Tuple>&&
     227             :           _S_declval();
     228             : 
     229             :         template<size_t... _Ind>
     230             :           auto
     231             :           _M_invoke(_Index_tuple<_Ind...>)
     232             :           noexcept(noexcept(std::__invoke(_S_declval<_Ind>()...)))
     233             :           -> decltype(std::__invoke(_S_declval<_Ind>()...))
     234             :           { return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
     235             : 
     236             :         using _Indices
     237             :           = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
     238             : 
     239             :         auto
     240             :         operator()()
     241             :         noexcept(noexcept(std::declval<_Invoker&>()._M_invoke(_Indices())))
     242             :         -> decltype(std::declval<_Invoker&>()._M_invoke(_Indices()))
     243             :         { return _M_invoke(_Indices()); }
     244             :       };
     245             : 
     246             :     template<typename... _Tp>
     247             :       using __decayed_tuple = tuple<typename std::decay<_Tp>::type...>;
     248             : 
     249             :   public:
     250             :     // Returns a call wrapper that stores
     251             :     // tuple{DECAY_COPY(__callable), DECAY_COPY(__args)...}.
     252             :     template<typename _Callable, typename... _Args>
     253             :       static _Invoker<__decayed_tuple<_Callable, _Args...>>
     254             :       __make_invoker(_Callable&& __callable, _Args&&... __args)
     255             :       {
     256             :         return { __decayed_tuple<_Callable, _Args...>{
     257             :             std::forward<_Callable>(__callable), std::forward<_Args>(__args)...
     258             :         } };
     259             :       }
     260             :   };
     261             : 
     262             :   inline void
     263             :   swap(thread& __x, thread& __y) noexcept
     264             :   { __x.swap(__y); }
     265             : 
     266             :   inline bool
     267             :   operator==(thread::id __x, thread::id __y) noexcept
     268             :   {
     269             :     // pthread_equal is undefined if either thread ID is not valid, so we
     270             :     // can't safely use __gthread_equal on default-constructed values (nor
     271             :     // the non-zero value returned by this_thread::get_id() for
     272             :     // single-threaded programs using GNU libc). Assume EqualityComparable.
     273             :     return __x._M_thread == __y._M_thread;
     274             :   }
     275             : 
     276             :   inline bool
     277             :   operator!=(thread::id __x, thread::id __y) noexcept
     278             :   { return !(__x == __y); }
     279             : 
     280             :   inline bool
     281             :   operator<(thread::id __x, thread::id __y) noexcept
     282             :   {
     283             :     // Pthreads doesn't define any way to do this, so we just have to
     284             :     // assume native_handle_type is LessThanComparable.
     285             :     return __x._M_thread < __y._M_thread;
     286             :   }
     287             : 
     288             :   inline bool
     289             :   operator<=(thread::id __x, thread::id __y) noexcept
     290             :   { return !(__y < __x); }
     291             : 
     292             :   inline bool
     293             :   operator>(thread::id __x, thread::id __y) noexcept
     294             :   { return __y < __x; }
     295             : 
     296             :   inline bool
     297             :   operator>=(thread::id __x, thread::id __y) noexcept
     298             :   { return !(__x < __y); }
     299             : 
     300             :   // DR 889.
     301             :   /// std::hash specialization for thread::id.
     302             :   template<>
     303             :     struct hash<thread::id>
     304             :     : public __hash_base<size_t, thread::id>
     305             :     {
     306             :       size_t
     307             :       operator()(const thread::id& __id) const noexcept
     308             :       { return std::_Hash_impl::hash(__id._M_thread); }
     309             :     };
     310             : 
     311             :   template<class _CharT, class _Traits>
     312             :     inline basic_ostream<_CharT, _Traits>&
     313             :     operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
     314             :     {
     315             :       if (__id == thread::id())
     316             :         return __out << "thread::id of a non-executing thread";
     317             :       else
     318             :         return __out << __id._M_thread;
     319             :     }
     320             : 
     321             : _GLIBCXX_END_NAMESPACE_VERSION
     322             : 
     323             :   /** @namespace std::this_thread
     324             :    *  @brief ISO C++ 2011 entities sub-namespace for thread.
     325             :    *  30.3.2 Namespace this_thread.
     326             :    */
     327             :   namespace this_thread
     328             :   {
     329             :   _GLIBCXX_BEGIN_NAMESPACE_VERSION
     330             : 
     331             :     /// get_id
     332             :     inline thread::id
     333             :     get_id() noexcept
     334             :     {
     335             : #ifdef __GLIBC__
     336             :       // For the GNU C library pthread_self() is usable without linking to
     337             :       // libpthread.so but returns 0, so we cannot use it in single-threaded
     338             :       // programs, because this_thread::get_id() != thread::id{} must be true.
     339             :       // We know that pthread_t is an integral type in the GNU C library.
     340             :       if (!__gthread_active_p())
     341             :         return thread::id(1);
     342             : #endif
     343             :       return thread::id(__gthread_self());
     344             :     }
     345             : 
     346             :     /// yield
     347             :     inline void
     348             :     yield() noexcept
     349             :     {
     350             : #ifdef _GLIBCXX_USE_SCHED_YIELD
     351             :       __gthread_yield();
     352             : #endif
     353             :     }
     354             : 
     355             :     void
     356             :     __sleep_for(chrono::seconds, chrono::nanoseconds);
     357             : 
     358             :     /// sleep_for
     359             :     template<typename _Rep, typename _Period>
     360             :       inline void
     361           5 :       sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
     362             :       {
     363           5 :         if (__rtime <= __rtime.zero())
     364           0 :           return;
     365           5 :         auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
     366           5 :         auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
     367             : #ifdef _GLIBCXX_USE_NANOSLEEP
     368          10 :         __gthread_time_t __ts =
     369             :           {
     370           5 :             static_cast<std::time_t>(__s.count()),
     371           5 :             static_cast<long>(__ns.count())
     372             :           };
     373           5 :         while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR)
     374             :           { }
     375             : #else
     376             :         __sleep_for(__s, __ns);
     377             : #endif
     378             :       }
     379             : 
     380             :     /// sleep_until
     381             :     template<typename _Clock, typename _Duration>
     382             :       inline void
     383             :       sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
     384             :       {
     385             :         auto __now = _Clock::now();
     386             :         if (_Clock::is_steady)
     387             :           {
     388             :             if (__now < __atime)
     389             :               sleep_for(__atime - __now);
     390             :             return;
     391             :           }
     392             :         while (__now < __atime)
     393             :           {
     394             :             sleep_for(__atime - __now);
     395             :             __now = _Clock::now();
     396             :           }
     397             :       }
     398             : 
     399             :   _GLIBCXX_END_NAMESPACE_VERSION
     400             :   }
     401             : 
     402             :   // @} group threads
     403             : 
     404             : } // namespace
     405             : 
     406             : #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
     407             : 
     408             : #endif // C++11
     409             : 
     410             : #endif // _GLIBCXX_THREAD

Generated by: LCOV version 1.13