xref: /llvm-project-15.0.7/libcxx/include/thread (revision 7f01ac39)
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();
30    template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
31    ~thread();
32
33    thread(const thread&) = delete;
34    thread(thread&& t);
35
36    thread& operator=(const thread&) = delete;
37    thread& operator=(thread&& t);
38
39    void swap(thread& t);
40
41    bool joinable() const;
42    void join();
43    void detach();
44    id get_id() const;
45    native_handle_type native_handle();
46
47    static unsigned hardware_concurrency();
48};
49
50void swap(thread& x, thread& y);
51
52class thread::id
53{
54public:
55    id();
56};
57
58bool operator==(thread::id x, thread::id y);
59bool operator!=(thread::id x, thread::id y);
60bool operator< (thread::id x, thread::id y);
61bool operator<=(thread::id x, thread::id y);
62bool operator> (thread::id x, thread::id y);
63bool operator>=(thread::id x, thread::id y);
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();
73
74void yield();
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#pragma GCC system_header
104
105#define __STDCPP_THREADS__ __cplusplus
106
107_LIBCPP_BEGIN_NAMESPACE_STD
108
109template <class _Tp>
110class __thread_specific_ptr
111{
112    pthread_key_t __key_;
113
114    __thread_specific_ptr(const __thread_specific_ptr&);
115    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
116
117    static void __at_thread_exit(void*);
118public:
119    typedef _Tp* pointer;
120
121    __thread_specific_ptr();
122    ~__thread_specific_ptr();
123
124    _LIBCPP_INLINE_VISIBILITY
125    pointer get() const {return static_cast<_Tp*>(pthread_getspecific(__key_));}
126    _LIBCPP_INLINE_VISIBILITY
127    pointer operator*() const {return *get();}
128    _LIBCPP_INLINE_VISIBILITY
129    pointer operator->() const {return get();}
130    pointer release();
131    void reset(pointer __p = nullptr);
132};
133
134template <class _Tp>
135void
136__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
137{
138	delete static_cast<pointer>(__p);
139}
140
141template <class _Tp>
142__thread_specific_ptr<_Tp>::__thread_specific_ptr()
143{
144    int __ec = pthread_key_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
145	if (__ec)
146		throw system_error(error_code(__ec, system_category()),
147		                   "__thread_specific_ptr construction failed");
148}
149
150template <class _Tp>
151__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
152{
153	pthread_key_delete(__key_);
154}
155
156template <class _Tp>
157typename __thread_specific_ptr<_Tp>::pointer
158__thread_specific_ptr<_Tp>::release()
159{
160	pointer __p = get();
161	pthread_setspecific(__key_, 0);
162	return __p;
163}
164
165template <class _Tp>
166void
167__thread_specific_ptr<_Tp>::reset(pointer __p)
168{
169	pointer __p_old = get();
170	pthread_setspecific(__key_, __p);
171	delete __p_old;
172}
173
174class thread;
175class __thread_id;
176
177namespace this_thread
178{
179
180__thread_id get_id();
181
182}  // this_thread
183
184class _LIBCPP_VISIBLE __thread_id
185{
186    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
187    // NULL is the no-thread value on Darwin.  Someone needs to check
188    // on other platforms.  We assume 0 works everywhere for now.
189    pthread_t __id_;
190
191public:
192    _LIBCPP_INLINE_VISIBILITY
193    __thread_id() : __id_(0) {}
194
195    friend _LIBCPP_INLINE_VISIBILITY
196        bool operator==(__thread_id __x, __thread_id __y)
197        {return __x.__id_ == __y.__id_;}
198    friend _LIBCPP_INLINE_VISIBILITY
199        bool operator!=(__thread_id __x, __thread_id __y)
200        {return !(__x == __y);}
201    friend _LIBCPP_INLINE_VISIBILITY
202        bool operator< (__thread_id __x, __thread_id __y)
203        {return __x.__id_ < __y.__id_;}
204    friend _LIBCPP_INLINE_VISIBILITY
205        bool operator<=(__thread_id __x, __thread_id __y)
206        {return !(__y < __x);}
207    friend _LIBCPP_INLINE_VISIBILITY
208        bool operator> (__thread_id __x, __thread_id __y)
209        {return   __y < __x ;}
210    friend _LIBCPP_INLINE_VISIBILITY
211        bool operator>=(__thread_id __x, __thread_id __y)
212        {return !(__x < __y);}
213
214    template<class _CharT, class _Traits>
215    friend
216    _LIBCPP_INLINE_VISIBILITY
217    basic_ostream<_CharT, _Traits>&
218    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
219        {return __os << __id.__id_;}
220
221private:
222    _LIBCPP_INLINE_VISIBILITY
223    __thread_id(pthread_t __id) : __id_(__id) {}
224
225    friend __thread_id this_thread::get_id();
226    friend class _LIBCPP_VISIBLE thread;
227};
228
229template<class _Tp> struct hash;
230
231template<>
232struct _LIBCPP_VISIBLE hash<__thread_id>
233    : public unary_function<__thread_id, size_t>
234{
235    _LIBCPP_INLINE_VISIBILITY
236    size_t operator()(__thread_id __v) const
237    {
238        const size_t* const __p = reinterpret_cast<const size_t*>(&__v);
239        return *__p;
240    }
241};
242
243namespace this_thread
244{
245
246inline _LIBCPP_INLINE_VISIBILITY
247__thread_id
248get_id()
249{
250    return pthread_self();
251}
252
253}  // this_thread
254
255class _LIBCPP_VISIBLE thread
256{
257    pthread_t __t_;
258
259    thread(const thread&);
260    thread& operator=(const thread&);
261public:
262    typedef __thread_id id;
263    typedef pthread_t native_handle_type;
264
265    _LIBCPP_INLINE_VISIBILITY
266    thread() : __t_(0) {}
267#ifndef _LIBCPP_HAS_NO_VARIADICS
268    template <class _F, class ..._Args,
269              class = typename enable_if
270              <
271                   !is_same<typename decay<_F>::type, thread>::value
272              >::type
273             >
274        explicit thread(_F&& __f, _Args&&... __args);
275#else  // _LIBCPP_HAS_NO_VARIADICS
276    template <class _F> explicit thread(_F __f);
277#endif
278    ~thread();
279
280#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
281    _LIBCPP_INLINE_VISIBILITY
282    thread(thread&& __t) : __t_(__t.__t_) {__t.__t_ = 0;}
283    thread& operator=(thread&& __t);
284#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
285
286    _LIBCPP_INLINE_VISIBILITY
287    void swap(thread& __t) {_VSTD::swap(__t_, __t.__t_);}
288
289    _LIBCPP_INLINE_VISIBILITY
290    bool joinable() const {return __t_ != 0;}
291    void join();
292    void detach();
293    _LIBCPP_INLINE_VISIBILITY
294    id get_id() const {return __t_;}
295    _LIBCPP_INLINE_VISIBILITY
296    native_handle_type native_handle() {return __t_;}
297
298    static unsigned hardware_concurrency();
299};
300
301class __assoc_sub_state;
302
303class _LIBCPP_HIDDEN __thread_struct_imp;
304
305class __thread_struct
306{
307    __thread_struct_imp* __p_;
308
309    __thread_struct(const __thread_struct&);
310    __thread_struct& operator=(const __thread_struct&);
311public:
312    __thread_struct();
313    ~__thread_struct();
314
315    void notify_all_at_thread_exit(condition_variable*, mutex*);
316    void __make_ready_at_thread_exit(__assoc_sub_state*);
317};
318
319__thread_specific_ptr<__thread_struct>& __thread_local_data();
320
321#ifndef _LIBCPP_HAS_NO_VARIADICS
322
323template <class _F, class ..._Args, size_t ..._Indices>
324inline _LIBCPP_INLINE_VISIBILITY
325void
326__threaad_execute(tuple<_F, _Args...>& __t, __tuple_indices<_Indices...>)
327{
328    __invoke(_VSTD::move(_VSTD::get<0>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
329}
330
331template <class _F>
332void*
333__thread_proxy(void* __vp)
334{
335    __thread_local_data().reset(new __thread_struct);
336    std::unique_ptr<_F> __p(static_cast<_F*>(__vp));
337    typedef typename __make_tuple_indices<tuple_size<_F>::value, 1>::type _Index;
338    __threaad_execute(*__p, _Index());
339    return nullptr;
340}
341
342template <class _F, class ..._Args,
343          class
344         >
345thread::thread(_F&& __f, _Args&&... __args)
346{
347    typedef tuple<typename decay<_F>::type, typename decay<_Args>::type...> _G;
348    _VSTD::unique_ptr<_G> __p(new _G(__decay_copy(_VSTD::forward<_F>(__f)),
349                                __decay_copy(_VSTD::forward<_Args>(__args))...));
350    int __ec = pthread_create(&__t_, 0, &__thread_proxy<_G>, __p.get());
351    if (__ec == 0)
352        __p.release();
353    else
354        __throw_system_error(__ec, "thread constructor failed");
355}
356
357#else  // _LIBCPP_HAS_NO_VARIADICS
358
359template <class _F>
360void*
361__thread_proxy(void* __vp)
362{
363    __thread_local_data().reset(new __thread_struct);
364    std::unique_ptr<_F> __p(static_cast<_F*>(__vp));
365    (*__p)();
366    return nullptr;
367}
368
369template <class _F>
370thread::thread(_F __f)
371{
372    std::unique_ptr<_F> __p(new _F(__f));
373    int __ec = pthread_create(&__t_, 0, &__thread_proxy<_F>, __p.get());
374    if (__ec == 0)
375        __p.release();
376    else
377        __throw_system_error(__ec, "thread constructor failed");
378}
379
380#endif  // _LIBCPP_HAS_NO_VARIADICS
381
382#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
383
384inline _LIBCPP_INLINE_VISIBILITY
385thread&
386thread::operator=(thread&& __t)
387{
388    if (__t_ != 0)
389        terminate();
390    __t_ = __t.__t_;
391    __t.__t_ = 0;
392    return *this;
393}
394
395#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
396
397inline _LIBCPP_INLINE_VISIBILITY
398void swap(thread& __x, thread& __y) {__x.swap(__y);}
399
400namespace this_thread
401{
402
403void sleep_for(const chrono::nanoseconds& ns);
404
405template <class _Rep, class _Period>
406void
407sleep_for(const chrono::duration<_Rep, _Period>& __d)
408{
409    using namespace chrono;
410    nanoseconds __ns = duration_cast<nanoseconds>(__d);
411    if (__ns < __d)
412        ++__ns;
413    sleep_for(__ns);
414}
415
416template <class _Clock, class _Duration>
417void
418sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
419{
420    using namespace chrono;
421    mutex __mut;
422    condition_variable __cv;
423    unique_lock<mutex> __lk(__mut);
424    while (_Clock::now() < __t)
425        __cv.wait_until(__lk, __t);
426}
427
428template <class _Duration>
429inline _LIBCPP_INLINE_VISIBILITY
430void
431sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
432{
433    using namespace chrono;
434    sleep_for(__t - steady_clock::now());
435}
436
437inline _LIBCPP_INLINE_VISIBILITY
438void yield() {sched_yield();}
439
440}  // this_thread
441
442_LIBCPP_END_NAMESPACE_STD
443
444#endif  // _LIBCPP_THREAD
445