xref: /llvm-project-15.0.7/libcxx/include/thread (revision a462f5cc)
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#include <pthread.h>
99
100#pragma GCC system_header
101
102#define __STDCPP_THREADS__ __cplusplus
103
104_LIBCPP_BEGIN_NAMESPACE_STD
105
106template <class _Tp>
107class __thread_specific_ptr
108{
109    pthread_key_t __key_;
110
111    __thread_specific_ptr(const __thread_specific_ptr&);
112    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
113
114    static void __at_thread_exit(void*);
115public:
116    typedef _Tp* pointer;
117
118    __thread_specific_ptr();
119    ~__thread_specific_ptr();
120
121    _LIBCPP_INLINE_VISIBILITY
122    pointer get() const {return static_cast<_Tp*>(pthread_getspecific(__key_));}
123    _LIBCPP_INLINE_VISIBILITY
124    pointer operator*() const {return *get();}
125    _LIBCPP_INLINE_VISIBILITY
126    pointer operator->() const {return get();}
127    pointer release();
128    void reset(pointer __p = nullptr);
129};
130
131template <class _Tp>
132void
133__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
134{
135	delete static_cast<pointer>(__p);
136}
137
138template <class _Tp>
139__thread_specific_ptr<_Tp>::__thread_specific_ptr()
140{
141    int __ec = pthread_key_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
142	if (__ec)
143		throw system_error(error_code(__ec, system_category()),
144		                   "__thread_specific_ptr construction failed");
145}
146
147template <class _Tp>
148__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
149{
150	pthread_key_delete(__key_);
151}
152
153template <class _Tp>
154typename __thread_specific_ptr<_Tp>::pointer
155__thread_specific_ptr<_Tp>::release()
156{
157	pointer __p = get();
158	pthread_setspecific(__key_, 0);
159	return __p;
160}
161
162template <class _Tp>
163void
164__thread_specific_ptr<_Tp>::reset(pointer __p)
165{
166	pointer __p_old = get();
167	pthread_setspecific(__key_, __p);
168	delete __p_old;
169}
170
171class thread;
172class __thread_id;
173
174namespace this_thread
175{
176
177__thread_id get_id();
178
179}  // this_thread
180
181class _LIBCPP_VISIBLE __thread_id
182{
183    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
184    // NULL is the no-thread value on Darwin.  Someone needs to check
185    // on other platforms.  We assume 0 works everywhere for now.
186    pthread_t __id_;
187
188public:
189    _LIBCPP_INLINE_VISIBILITY
190    __thread_id() : __id_(0) {}
191
192    friend _LIBCPP_INLINE_VISIBILITY
193        bool operator==(__thread_id __x, __thread_id __y)
194        {return __x.__id_ == __y.__id_;}
195    friend _LIBCPP_INLINE_VISIBILITY
196        bool operator!=(__thread_id __x, __thread_id __y)
197        {return !(__x == __y);}
198    friend _LIBCPP_INLINE_VISIBILITY
199        bool operator< (__thread_id __x, __thread_id __y)
200        {return __x.__id_ < __y.__id_;}
201    friend _LIBCPP_INLINE_VISIBILITY
202        bool operator<=(__thread_id __x, __thread_id __y)
203        {return !(__y < __x);}
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 !(__x < __y);}
210
211    template<class _CharT, class _Traits>
212    friend
213    _LIBCPP_INLINE_VISIBILITY
214    basic_ostream<_CharT, _Traits>&
215    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
216        {return __os << __id.__id_;}
217
218private:
219    _LIBCPP_INLINE_VISIBILITY
220    __thread_id(pthread_t __id) : __id_(__id) {}
221
222    friend __thread_id this_thread::get_id();
223    friend class _LIBCPP_VISIBLE thread;
224};
225
226template<class _Tp> struct hash;
227
228template<>
229struct _LIBCPP_VISIBLE hash<__thread_id>
230    : public unary_function<__thread_id, size_t>
231{
232    _LIBCPP_INLINE_VISIBILITY
233    size_t operator()(__thread_id __v) const
234    {
235        const size_t* const __p = reinterpret_cast<const size_t*>(&__v);
236        return *__p;
237    }
238};
239
240namespace this_thread
241{
242
243inline _LIBCPP_INLINE_VISIBILITY
244__thread_id
245get_id()
246{
247    return pthread_self();
248}
249
250}  // this_thread
251
252class _LIBCPP_VISIBLE thread
253{
254    pthread_t __t_;
255
256    thread(const thread&);
257    thread& operator=(const thread&);
258public:
259    typedef __thread_id id;
260    typedef pthread_t native_handle_type;
261
262    _LIBCPP_INLINE_VISIBILITY
263    thread() : __t_(0) {}
264#ifndef _LIBCPP_HAS_NO_VARIADICS
265    template <class _F, class ..._Args,
266              class = typename enable_if
267              <
268                   !is_same<typename decay<_F>::type, thread>::value
269              >::type
270             >
271        explicit thread(_F&& __f, _Args&&... __args);
272#else  // _LIBCPP_HAS_NO_VARIADICS
273    template <class _F> explicit thread(_F __f);
274#endif
275    ~thread();
276
277#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
278    _LIBCPP_INLINE_VISIBILITY
279    thread(thread&& __t) : __t_(__t.__t_) {__t.__t_ = 0;}
280    thread& operator=(thread&& __t);
281#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
282
283    _LIBCPP_INLINE_VISIBILITY
284    void swap(thread& __t) {_STD::swap(__t_, __t.__t_);}
285
286    _LIBCPP_INLINE_VISIBILITY
287    bool joinable() const {return __t_ != 0;}
288    void join();
289    void detach();
290    _LIBCPP_INLINE_VISIBILITY
291    id get_id() const {return __t_;}
292    _LIBCPP_INLINE_VISIBILITY
293    native_handle_type native_handle() {return __t_;}
294
295    static unsigned hardware_concurrency();
296};
297
298class __assoc_sub_state;
299
300class _LIBCPP_HIDDEN __thread_struct_imp;
301
302class __thread_struct
303{
304    __thread_struct_imp* __p_;
305
306    __thread_struct(const __thread_struct&);
307    __thread_struct& operator=(const __thread_struct&);
308public:
309    __thread_struct();
310    ~__thread_struct();
311
312    void notify_all_at_thread_exit(condition_variable*, mutex*);
313    void __make_ready_at_thread_exit(__assoc_sub_state*);
314};
315
316__thread_specific_ptr<__thread_struct>& __thread_local_data();
317
318template <class _F>
319void*
320__thread_proxy(void* __vp)
321{
322    __thread_local_data().reset(new __thread_struct);
323    std::unique_ptr<_F> __p(static_cast<_F*>(__vp));
324    (*__p)();
325    return nullptr;
326}
327
328#ifndef _LIBCPP_HAS_NO_VARIADICS
329
330template <class _F, class ..._Args,
331          class
332         >
333thread::thread(_F&& __f, _Args&&... __args)
334{
335    typedef decltype(bind(std::forward<_F>(__f), std::forward<_Args>(__args)...)) _G;
336    std::unique_ptr<_G> __p(new _G(bind(std::forward<_F>(__f),
337                              std::forward<_Args>(__args)...)));
338    int __ec = pthread_create(&__t_, 0, &__thread_proxy<_G>, __p.get());
339    if (__ec == 0)
340        __p.release();
341    else
342        __throw_system_error(__ec, "thread constructor failed");
343}
344
345#else  // _LIBCPP_HAS_NO_VARIADICS
346
347template <class _F>
348thread::thread(_F __f)
349{
350    std::unique_ptr<_F> __p(new _F(__f));
351    int __ec = pthread_create(&__t_, 0, &__thread_proxy<_F>, __p.get());
352    if (__ec == 0)
353        __p.release();
354    else
355        __throw_system_error(__ec, "thread constructor failed");
356}
357
358#endif  // _LIBCPP_HAS_NO_VARIADICS
359
360#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
361
362inline _LIBCPP_INLINE_VISIBILITY
363thread&
364thread::operator=(thread&& __t)
365{
366    if (__t_ != 0)
367        terminate();
368    __t_ = __t.__t_;
369    __t.__t_ = 0;
370    return *this;
371}
372
373#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
374
375inline _LIBCPP_INLINE_VISIBILITY
376void swap(thread& __x, thread& __y) {__x.swap(__y);}
377
378namespace this_thread
379{
380
381void sleep_for(const chrono::nanoseconds& ns);
382
383template <class _Rep, class _Period>
384void
385sleep_for(const chrono::duration<_Rep, _Period>& __d)
386{
387    using namespace chrono;
388    nanoseconds __ns = duration_cast<nanoseconds>(__d);
389    if (__ns < __d)
390        ++__ns;
391    sleep_for(__ns);
392}
393
394template <class _Clock, class _Duration>
395void
396sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
397{
398    using namespace chrono;
399    mutex __mut;
400    condition_variable __cv;
401    unique_lock<mutex> __lk(__mut);
402    while (_Clock::now() < __t)
403        __cv.wait_until(__lk, __t);
404}
405
406template <class _Duration>
407inline _LIBCPP_INLINE_VISIBILITY
408void
409sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
410{
411    using namespace chrono;
412    sleep_for(__t - steady_clock::now());
413}
414
415inline _LIBCPP_INLINE_VISIBILITY
416void yield() {sched_yield();}
417
418}  // this_thread
419
420_LIBCPP_END_NAMESPACE_STD
421
422#endif  // _LIBCPP_THREAD
423