// <thread> -*- 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 // <http://www.gnu.org/licenses/>. /** @file include/thread * This is a Standard C++ Library header. */ #ifndef _GLIBCXX_THREAD #define _GLIBCXX_THREAD 1 #pragma GCC system_header #if __cplusplus < 201103L # include <bits/c++0x_warning.h> #else #include <chrono> #include <memory> #include <tuple> #include <cerrno> #include <bits/functexcept.h> #include <bits/functional_hash.h> #include <bits/invoke.h> #include <bits/gthr.h> #if defined(_GLIBCXX_HAS_GTHREADS) && 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<_State>; 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<thread::id>; friend bool operator==(thread::id __x, thread::id __y) noexcept; friend bool operator<(thread::id __x, thread::id __y) noexcept; template<class _CharT, class _Traits> friend basic_ostream<_CharT, _Traits>& operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id); }; private: id _M_id; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2097. packaged_task constructors should be constrained template<typename _Tp> using __not_same = __not_<is_same< typename remove_cv<typename remove_reference<_Tp>::type>::type, thread>>; public: thread() noexcept = default; template<typename _Callable, typename... _Args, typename = _Require<__not_same<_Callable>>> explicit thread(_Callable&& __f, _Args&&... __args) { static_assert( __is_invocable<typename decay<_Callable>::type, typename decay<_Args>::type...>::value, "std::thread arguments must be invocable after conversion to rvalues" ); #ifdef GTHR_ACTIVE_PROXY // Create a reference to pthread_create, not just the gthr weak symbol. auto __depend = reinterpret_cast<void(*)()>(&pthread_create); #else auto __depend = nullptr; #endif _M_start_thread(_S_make_state( __make_invoker(std::forward<_Callable>(__f), std::forward<_Args>(__args)...)), __depend); } ~thread() { if (joinable()) std::terminate(); } thread(const thread&) = delete; thread(thread&& __t) noexcept { swap(__t); } thread& operator=(const thread&) = delete; thread& operator=(thread&& __t) noexcept { if (joinable()) std::terminate(); swap(__t); return *this; } void swap(thread& __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<typename _Callable> struct _State_impl : public _State { _Callable _M_func; _State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f)) { } void _M_run() { _M_func(); } }; void _M_start_thread(_State_ptr, void (*)()); template<typename _Callable> static _State_ptr _S_make_state(_Callable&& __f) { using _Impl = _State_impl<_Callable>; return _State_ptr{new _Impl{std::forward<_Callable>(__f)}}; } #if _GLIBCXX_THREAD_ABI_COMPAT public: struct _Impl_base; typedef shared_ptr<_Impl_base> __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<typename _Tuple> struct _Invoker { _Tuple _M_t; template<size_t _Index> static __tuple_element_t<_Index, _Tuple>&& _S_declval(); template<size_t... _Ind> auto _M_invoke(_Index_tuple<_Ind...>) noexcept(noexcept(std::__invoke(_S_declval<_Ind>()...))) -> decltype(std::__invoke(_S_declval<_Ind>()...)) { return std::__invoke(std::get<_Ind>(std::move(_M_t))...); } using _Indices = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type; auto operator()() noexcept(noexcept(std::declval<_Invoker&>()._M_invoke(_Indices()))) -> decltype(std::declval<_Invoker&>()._M_invoke(_Indices())) { return _M_invoke(_Indices()); } }; template<typename... _Tp> using __decayed_tuple = tuple<typename std::decay<_Tp>::type...>; public: // Returns a call wrapper that stores // tuple{DECAY_COPY(__callable), DECAY_COPY(__args)...}. template<typename _Callable, typename... _Args> static _Invoker<__decayed_tuple<_Callable, _Args...>> __make_invoker(_Callable&& __callable, _Args&&... __args) { return { __decayed_tuple<_Callable, _Args...>{ std::forward<_Callable>(__callable), std::forward<_Args>(__args)... } }; } }; inline void swap(thread& __x, thread& __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<(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 < __y._M_thread; } inline bool operator<=(thread::id __x, thread::id __y) noexcept { return !(__y < __x); } inline bool operator>(thread::id __x, thread::id __y) noexcept { return __y < __x; } inline bool operator>=(thread::id __x, thread::id __y) noexcept { return !(__x < __y); } // DR 889. /// std::hash specialization for thread::id. template<> struct hash<thread::id> : public __hash_base<size_t, thread::id> { size_t operator()(const thread::id& __id) const noexcept { return std::_Hash_impl::hash(__id._M_thread); } }; template<class _CharT, class _Traits> inline basic_ostream<_CharT, _Traits>& operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id) { if (__id == thread::id()) return __out << "thread::id of a non-executing thread"; else return __out << __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<typename _Rep, typename _Period> inline void sleep_for(const chrono::duration<_Rep, _Period>& __rtime) { if (__rtime <= __rtime.zero()) return; auto __s = chrono::duration_cast<chrono::seconds>(__rtime); auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s); #ifdef _GLIBCXX_USE_NANOSLEEP __gthread_time_t __ts = { static_cast<std::time_t>(__s.count()), static_cast<long>(__ns.count()) }; while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR) { } #else __sleep_for(__s, __ns); #endif } /// sleep_until template<typename _Clock, typename _Duration> inline void sleep_until(const chrono::time_point<_Clock, _Duration>& __atime) { auto __now = _Clock::now(); if (_Clock::is_steady) { if (__now < __atime) sleep_for(__atime - __now); return; } while (__now < __atime) { sleep_for(__atime - __now); __now = _Clock::now(); } } } // @} group threads _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 #endif // C++11 #endif // _GLIBCXX_THREAD