xref: /llvm-project-15.0.7/libcxx/include/thread (revision 9ad94aa2) 
1// -*- C++ -*-
2//===--------------------------- thread -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_THREAD
12#define _LIBCPP_THREAD
13
14/*
15
16    thread synopsis
17
18#define __STDCPP_THREADS__ __cplusplus
19
20namespace std
21{
22
23class thread
24{
25public:
26    class id;
27    typedef pthread_t native_handle_type;
28
29    thread() noexcept;
30    template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
31    ~thread();
32
33    thread(const thread&) = delete;
34    thread(thread&& t) noexcept;
35
36    thread& operator=(const thread&) = delete;
37    thread& operator=(thread&& t) noexcept;
38
39    void swap(thread& t) noexcept;
40
41    bool joinable() const noexcept;
42    void join();
43    void detach();
44    id get_id() const noexcept;
45    native_handle_type native_handle();
46
47    static unsigned hardware_concurrency() noexcept;
48};
49
50void swap(thread& x, thread& y) noexcept;
51
52class thread::id
53{
54public:
55    id() noexcept;
56};
57
58bool operator==(thread::id x, thread::id y) noexcept;
59bool operator!=(thread::id x, thread::id y) noexcept;
60bool operator< (thread::id x, thread::id y) noexcept;
61bool operator<=(thread::id x, thread::id y) noexcept;
62bool operator> (thread::id x, thread::id y) noexcept;
63bool operator>=(thread::id x, thread::id y) noexcept;
64
65template<class charT, class traits>
66basic_ostream<charT, traits>&
67operator<<(basic_ostream<charT, traits>& out, thread::id id);
68
69namespace this_thread
70{
71
72thread::id get_id() noexcept;
73
74void yield() noexcept;
75
76template <class Clock, class Duration>
77void sleep_until(const chrono::time_point<Clock, Duration>& abs_time);
78
79template <class Rep, class Period>
80void sleep_for(const chrono::duration<Rep, Period>& rel_time);
81
82}  // this_thread
83
84}  // std
85
86*/
87
88#include <__config>
89#include <iosfwd>
90#include <__functional_base>
91#include <type_traits>
92#include <cstddef>
93#include <functional>
94#include <memory>
95#include <system_error>
96#include <chrono>
97#include <__mutex_base>
98#ifndef _LIBCPP_HAS_NO_VARIADICS
99#include <tuple>
100#endif
101#include <pthread.h>
102
103#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
104#pragma GCC system_header
105#endif
106
107#define __STDCPP_THREADS__ __cplusplus
108
109#ifdef _LIBCPP_HAS_NO_THREADS
110#error <thread> is not supported on this single threaded system
111#else // !_LIBCPP_HAS_NO_THREADS
112
113_LIBCPP_BEGIN_NAMESPACE_STD
114
115template <class _Tp>
116class __thread_specific_ptr
117{
118    pthread_key_t __key_;
119
120    __thread_specific_ptr(const __thread_specific_ptr&);
121    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
122
123    static void __at_thread_exit(void*);
124public:
125    typedef _Tp* pointer;
126
127    __thread_specific_ptr();
128    ~__thread_specific_ptr();
129
130    _LIBCPP_INLINE_VISIBILITY
131    pointer get() const {return static_cast<_Tp*>(pthread_getspecific(__key_));}
132    _LIBCPP_INLINE_VISIBILITY
133    pointer operator*() const {return *get();}
134    _LIBCPP_INLINE_VISIBILITY
135    pointer operator->() const {return get();}
136    pointer release();
137    void reset(pointer __p = nullptr);
138};
139
140template <class _Tp>
141void
142__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
143{
144    delete static_cast<pointer>(__p);
145}
146
147template <class _Tp>
148__thread_specific_ptr<_Tp>::__thread_specific_ptr()
149{
150    int __ec = pthread_key_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
151#ifndef _LIBCPP_NO_EXCEPTIONS
152    if (__ec)
153        throw system_error(error_code(__ec, system_category()),
154                           "__thread_specific_ptr construction failed");
155#endif
156}
157
158template <class _Tp>
159__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
160{
161    pthread_key_delete(__key_);
162}
163
164template <class _Tp>
165typename __thread_specific_ptr<_Tp>::pointer
166__thread_specific_ptr<_Tp>::release()
167{
168    pointer __p = get();
169    pthread_setspecific(__key_, 0);
170    return __p;
171}
172
173template <class _Tp>
174void
175__thread_specific_ptr<_Tp>::reset(pointer __p)
176{
177    pointer __p_old = get();
178    pthread_setspecific(__key_, __p);
179    delete __p_old;
180}
181
182class _LIBCPP_TYPE_VIS thread;
183class _LIBCPP_TYPE_VIS __thread_id;
184
185namespace this_thread
186{
187
188_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
189
190}  // this_thread
191
192template<> struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;
193
194class _LIBCPP_TYPE_VIS_ONLY __thread_id
195{
196    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
197    // NULL is the no-thread value on Darwin.  Someone needs to check
198    // on other platforms.  We assume 0 works everywhere for now.
199    pthread_t __id_;
200
201public:
202    _LIBCPP_INLINE_VISIBILITY
203    __thread_id() _NOEXCEPT : __id_(0) {}
204
205    friend _LIBCPP_INLINE_VISIBILITY
206        bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
207        {return __x.__id_ == __y.__id_;}
208    friend _LIBCPP_INLINE_VISIBILITY
209        bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
210        {return !(__x == __y);}
211    friend _LIBCPP_INLINE_VISIBILITY
212        bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
213        {return __x.__id_ < __y.__id_;}
214    friend _LIBCPP_INLINE_VISIBILITY
215        bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
216        {return !(__y < __x);}
217    friend _LIBCPP_INLINE_VISIBILITY
218        bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
219        {return   __y < __x ;}
220    friend _LIBCPP_INLINE_VISIBILITY
221        bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
222        {return !(__x < __y);}
223
224    template<class _CharT, class _Traits>
225    friend
226    _LIBCPP_INLINE_VISIBILITY
227    basic_ostream<_CharT, _Traits>&
228    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
229        {return __os << __id.__id_;}
230
231private:
232    _LIBCPP_INLINE_VISIBILITY
233    __thread_id(pthread_t __id) : __id_(__id) {}
234
235    friend __thread_id this_thread::get_id() _NOEXCEPT;
236    friend class _LIBCPP_TYPE_VIS thread;
237    friend struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;
238};
239
240template<>
241struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>
242    : public unary_function<__thread_id, size_t>
243{
244    _LIBCPP_INLINE_VISIBILITY
245    size_t operator()(__thread_id __v) const
246    {
247        return hash<pthread_t>()(__v.__id_);
248    }
249};
250
251namespace this_thread
252{
253
254inline _LIBCPP_INLINE_VISIBILITY
255__thread_id
256get_id() _NOEXCEPT
257{
258    return pthread_self();
259}
260
261}  // this_thread
262
263class _LIBCPP_TYPE_VIS thread
264{
265    pthread_t __t_;
266
267    thread(const thread&);
268    thread& operator=(const thread&);
269public:
270    typedef __thread_id id;
271    typedef pthread_t native_handle_type;
272
273    _LIBCPP_INLINE_VISIBILITY
274    thread() _NOEXCEPT : __t_(0) {}
275#ifndef _LIBCPP_HAS_NO_VARIADICS
276    template <class _Fp, class ..._Args,
277              class = typename enable_if
278              <
279                   !is_same<typename decay<_Fp>::type, thread>::value
280              >::type
281             >
282        explicit thread(_Fp&& __f, _Args&&... __args);
283#else  // _LIBCPP_HAS_NO_VARIADICS
284    template <class _Fp> explicit thread(_Fp __f);
285#endif
286    ~thread();
287
288#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
289    _LIBCPP_INLINE_VISIBILITY
290    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = 0;}
291    thread& operator=(thread&& __t) _NOEXCEPT;
292#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
293
294    _LIBCPP_INLINE_VISIBILITY
295    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
296
297    _LIBCPP_INLINE_VISIBILITY
298    bool joinable() const _NOEXCEPT {return __t_ != 0;}
299    void join();
300    void detach();
301    _LIBCPP_INLINE_VISIBILITY
302    id get_id() const _NOEXCEPT {return __t_;}
303    _LIBCPP_INLINE_VISIBILITY
304    native_handle_type native_handle() _NOEXCEPT {return __t_;}
305
306    static unsigned hardware_concurrency() _NOEXCEPT;
307};
308
309class __assoc_sub_state;
310
311class _LIBCPP_HIDDEN __thread_struct_imp;
312
313class _LIBCPP_TYPE_VIS __thread_struct
314{
315    __thread_struct_imp* __p_;
316
317    __thread_struct(const __thread_struct&);
318    __thread_struct& operator=(const __thread_struct&);
319public:
320    __thread_struct();
321    ~__thread_struct();
322
323    void notify_all_at_thread_exit(condition_variable*, mutex*);
324    void __make_ready_at_thread_exit(__assoc_sub_state*);
325};
326
327_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
328
329#ifndef _LIBCPP_HAS_NO_VARIADICS
330
331template <class _Fp, class ..._Args, size_t ..._Indices>
332inline _LIBCPP_INLINE_VISIBILITY
333void
334__thread_execute(tuple<_Fp, _Args...>& __t, __tuple_indices<_Indices...>)
335{
336    __invoke(_VSTD::move(_VSTD::get<0>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
337}
338
339template <class _Fp>
340void*
341__thread_proxy(void* __vp)
342{
343    __thread_local_data().reset(new __thread_struct);
344    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
345    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
346    __thread_execute(*__p, _Index());
347    return nullptr;
348}
349
350template <class _Fp, class ..._Args,
351          class
352         >
353thread::thread(_Fp&& __f, _Args&&... __args)
354{
355    typedef tuple<typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
356    _VSTD::unique_ptr<_Gp> __p(new _Gp(__decay_copy(_VSTD::forward<_Fp>(__f)),
357                                __decay_copy(_VSTD::forward<_Args>(__args))...));
358    int __ec = pthread_create(&__t_, 0, &__thread_proxy<_Gp>, __p.get());
359    if (__ec == 0)
360        __p.release();
361    else
362        __throw_system_error(__ec, "thread constructor failed");
363}
364
365#else  // _LIBCPP_HAS_NO_VARIADICS
366
367template <class _Fp>
368void*
369__thread_proxy(void* __vp)
370{
371    __thread_local_data().reset(new __thread_struct);
372    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
373    (*__p)();
374    return nullptr;
375}
376
377template <class _Fp>
378thread::thread(_Fp __f)
379{
380    std::unique_ptr<_Fp> __p(new _Fp(__f));
381    int __ec = pthread_create(&__t_, 0, &__thread_proxy<_Fp>, __p.get());
382    if (__ec == 0)
383        __p.release();
384    else
385        __throw_system_error(__ec, "thread constructor failed");
386}
387
388#endif  // _LIBCPP_HAS_NO_VARIADICS
389
390#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
391
392inline _LIBCPP_INLINE_VISIBILITY
393thread&
394thread::operator=(thread&& __t) _NOEXCEPT
395{
396    if (__t_ != 0)
397        terminate();
398    __t_ = __t.__t_;
399    __t.__t_ = 0;
400    return *this;
401}
402
403#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
404
405inline _LIBCPP_INLINE_VISIBILITY
406void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
407
408namespace this_thread
409{
410
411_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& ns);
412
413template <class _Rep, class _Period>
414void
415sleep_for(const chrono::duration<_Rep, _Period>& __d)
416{
417    using namespace chrono;
418    if (__d > duration<_Rep, _Period>::zero())
419    {
420        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
421        nanoseconds __ns;
422        if (__d < _Max)
423        {
424            __ns = duration_cast<nanoseconds>(__d);
425            if (__ns < __d)
426                ++__ns;
427        }
428        else
429            __ns = nanoseconds::max();
430        sleep_for(__ns);
431    }
432}
433
434template <class _Clock, class _Duration>
435void
436sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
437{
438    using namespace chrono;
439    mutex __mut;
440    condition_variable __cv;
441    unique_lock<mutex> __lk(__mut);
442    while (_Clock::now() < __t)
443        __cv.wait_until(__lk, __t);
444}
445
446template <class _Duration>
447inline _LIBCPP_INLINE_VISIBILITY
448void
449sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
450{
451    using namespace chrono;
452    sleep_for(__t - steady_clock::now());
453}
454
455inline _LIBCPP_INLINE_VISIBILITY
456void yield() _NOEXCEPT {sched_yield();}
457
458}  // this_thread
459
460_LIBCPP_END_NAMESPACE_STD
461
462#endif // !_LIBCPP_HAS_NO_THREADS
463
464#endif  // _LIBCPP_THREAD
465