1 // <thread> -*- C++ -*-
3 // Copyright (C) 2008-2016 Free Software Foundation, Inc.
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)
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.
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.
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/>.
25 /** @file include/thread
26 * This is a Standard C++ Library header.
29 #ifndef _GLIBCXX_THREAD
30 #define _GLIBCXX_THREAD 1
32 #pragma GCC system_header
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
42 #include <bits/functexcept.h>
43 #include <bits/functional_hash.h>
44 #include <bits/invoke.h>
45 #include <bits/gthr.h>
47 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
49 namespace std _GLIBCXX_VISIBILITY(default)
51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
54 * @defgroup threads Threads
55 * @ingroup concurrency
57 * Classes for thread support.
65 // Abstract base class for types that wrap arbitrary functors to be
66 // invoked in the new thread of execution.
70 virtual void _M_run() = 0;
72 using _State_ptr = unique_ptr<_State>;
74 typedef __gthread_t native_handle_type;
79 native_handle_type _M_thread;
82 id() noexcept : _M_thread() { }
85 id(native_handle_type __id) : _M_thread(__id) { }
89 friend class hash<thread::id>;
92 operator==(thread::id __x, thread::id __y) noexcept;
95 operator<(thread::id __x, thread::id __y) noexcept;
97 template<class _CharT, class _Traits>
98 friend basic_ostream<_CharT, _Traits>&
99 operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id);
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;
112 thread(thread&& __t) noexcept
115 template<typename _Callable, typename... _Args>
117 thread(_Callable&& __f, _Args&&... __args)
119 #ifdef GTHR_ACTIVE_PROXY
120 // Create a reference to pthread_create, not just the gthr weak symbol.
121 auto __depend = reinterpret_cast<void(*)()>(&pthread_create);
123 auto __depend = nullptr;
125 _M_start_thread(_S_make_state(
126 __make_invoker(std::forward<_Callable>(__f),
127 std::forward<_Args>(__args)...)),
137 thread& operator=(const thread&) = delete;
139 thread& operator=(thread&& __t) noexcept
148 swap(thread& __t) noexcept
149 { std::swap(_M_id, __t._M_id); }
152 joinable() const noexcept
153 { return !(_M_id == id()); }
162 get_id() const noexcept
165 /** @pre thread is joinable
169 { return _M_id._M_thread; }
171 // Returns a value that hints at the number of hardware thread contexts.
173 hardware_concurrency() noexcept;
176 template<typename _Callable>
177 struct _State_impl : public _State
181 _State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f))
185 _M_run() { _M_func(); }
189 _M_start_thread(_State_ptr, void (*)());
191 template<typename _Callable>
193 _S_make_state(_Callable&& __f)
195 using _Impl = _State_impl<_Callable>;
196 return _State_ptr{new _Impl{std::forward<_Callable>(__f)}};
198 #if _GLIBCXX_THREAD_ABI_COMPAT
201 typedef shared_ptr<_Impl_base> __shared_base_type;
204 __shared_base_type _M_this_ptr;
205 virtual ~_Impl_base() = default;
206 virtual void _M_run() = 0;
211 _M_start_thread(__shared_base_type, void (*)());
214 _M_start_thread(__shared_base_type);
218 // A call wrapper that does INVOKE(forwarded tuple elements...)
219 template<typename _Tuple>
224 template<size_t _Index>
225 static __tuple_element_t<_Index, _Tuple>&&
228 template<size_t... _Ind>
230 _M_invoke(_Index_tuple<_Ind...>)
231 noexcept(noexcept(std::__invoke(_S_declval<_Ind>()...)))
232 -> decltype(std::__invoke(_S_declval<_Ind>()...))
233 { return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
236 = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
240 noexcept(noexcept(std::declval<_Invoker&>()._M_invoke(_Indices())))
241 -> decltype(std::declval<_Invoker&>()._M_invoke(_Indices()))
242 { return _M_invoke(_Indices()); }
245 // Alias for _Invoker<tuple<DECAY_COPY(_Tp)...>>
246 template<typename... _Tp>
248 = _Invoker<decltype(std::make_tuple(std::declval<_Tp>()...))>;
251 // Returns a call wrapper that does
252 // INVOKE(DECAY_COPY(__callable), DECAY_COPY(__args)).
253 template<typename _Callable, typename... _Args>
254 static __invoker_type<_Callable, _Args...>
255 __make_invoker(_Callable&& __callable, _Args&&... __args)
258 std::make_tuple(std::forward<_Callable>(__callable),
259 std::forward<_Args>(__args)...)
265 swap(thread& __x, thread& __y) noexcept
269 operator==(thread::id __x, thread::id __y) noexcept
271 // pthread_equal is undefined if either thread ID is not valid, so we
272 // can't safely use __gthread_equal on default-constructed values (nor
273 // the non-zero value returned by this_thread::get_id() for
274 // single-threaded programs using GNU libc). Assume EqualityComparable.
275 return __x._M_thread == __y._M_thread;
279 operator!=(thread::id __x, thread::id __y) noexcept
280 { return !(__x == __y); }
283 operator<(thread::id __x, thread::id __y) noexcept
285 // Pthreads doesn't define any way to do this, so we just have to
286 // assume native_handle_type is LessThanComparable.
287 return __x._M_thread < __y._M_thread;
291 operator<=(thread::id __x, thread::id __y) noexcept
292 { return !(__y < __x); }
295 operator>(thread::id __x, thread::id __y) noexcept
296 { return __y < __x; }
299 operator>=(thread::id __x, thread::id __y) noexcept
300 { return !(__x < __y); }
303 /// std::hash specialization for thread::id.
305 struct hash<thread::id>
306 : public __hash_base<size_t, thread::id>
309 operator()(const thread::id& __id) const noexcept
310 { return std::_Hash_impl::hash(__id._M_thread); }
313 template<class _CharT, class _Traits>
314 inline basic_ostream<_CharT, _Traits>&
315 operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
317 if (__id == thread::id())
318 return __out << "thread::id of a non-executing thread";
320 return __out << __id._M_thread;
323 _GLIBCXX_END_NAMESPACE_VERSION
325 /** @namespace std::this_thread
326 * @brief ISO C++ 2011 entities sub-namespace for thread.
327 * 30.3.2 Namespace this_thread.
329 namespace this_thread
331 _GLIBCXX_BEGIN_NAMESPACE_VERSION
338 // For the GNU C library pthread_self() is usable without linking to
339 // libpthread.so but returns 0, so we cannot use it in single-threaded
340 // programs, because this_thread::get_id() != thread::id{} must be true.
341 // We know that pthread_t is an integral type in the GNU C library.
342 if (!__gthread_active_p())
343 return thread::id(1);
345 return thread::id(__gthread_self());
352 #ifdef _GLIBCXX_USE_SCHED_YIELD
358 __sleep_for(chrono::seconds, chrono::nanoseconds);
361 template<typename _Rep, typename _Period>
363 sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
365 if (__rtime <= __rtime.zero())
367 auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
368 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
369 #ifdef _GLIBCXX_USE_NANOSLEEP
370 __gthread_time_t __ts =
372 static_cast<std::time_t>(__s.count()),
373 static_cast<long>(__ns.count())
375 while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR)
378 __sleep_for(__s, __ns);
383 template<typename _Clock, typename _Duration>
385 sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
387 auto __now = _Clock::now();
388 if (_Clock::is_steady)
391 sleep_for(__atime - __now);
394 while (__now < __atime)
396 sleep_for(__atime - __now);
397 __now = _Clock::now();
401 _GLIBCXX_END_NAMESPACE_VERSION
408 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
412 #endif // _GLIBCXX_THREAD