1// <thread> -*- C++ -*- 
2 
3// Copyright (C) 2008-2021 Free Software Foundation, Inc. 
4// 
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) 
9// any later version. 
10 
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. 
15 
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. 
19 
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/>. 
24 
25/** @file include/thread 
26 * This is a Standard C++ Library header. 
27 */ 
28 
29#ifndef _GLIBCXX_THREAD 
30#define _GLIBCXX_THREAD 1 
31 
32#pragma GCC system_header 
33 
34#if __cplusplus < 201103L 
35# include <bits/c++0x_warning.h> 
36#else 
37 
38#if __cplusplus > 201703L 
39# include <compare> // std::strong_ordering 
40# include <stop_token> // std::stop_source, std::stop_token, std::nostopstate 
41#endif 
42 
43#include <bits/std_thread.h> // std::thread, get_id, yield 
44#include <bits/this_thread_sleep.h> // std::this_thread::sleep_for, sleep_until 
45 
46namespace std _GLIBCXX_VISIBILITY(default) 
47{ 
48_GLIBCXX_BEGIN_NAMESPACE_VERSION 
49 
50 /** 
51 * @defgroup threads Threads 
52 * @ingroup concurrency 
53 * 
54 * Classes for thread support. 
55 * @{ 
56 */ 
57 
58 // std::thread is defined in <bits/std_thread.h> 
59 
60#if __cpp_lib_three_way_comparison 
61 inline strong_ordering 
62 operator<=>(thread::id __x, thread::id __y) noexcept 
63 { return __x._M_thread <=> __y._M_thread; } 
64#else 
65 inline bool 
66 operator!=(thread::id __x, thread::id __y) noexcept 
67 { return !(__x == __y); } 
68 
69 inline bool 
70 operator<(thread::id __x, thread::id __y) noexcept 
71 { 
72 // Pthreads doesn't define any way to do this, so we just have to 
73 // assume native_handle_type is LessThanComparable. 
74 return __x._M_thread < __y._M_thread; 
75 } 
76 
77 inline bool 
78 operator<=(thread::id __x, thread::id __y) noexcept 
79 { return !(__y < __x); } 
80 
81 inline bool 
82 operator>(thread::id __x, thread::id __y) noexcept 
83 { return __y < __x; } 
84 
85 inline bool 
86 operator>=(thread::id __x, thread::id __y) noexcept 
87 { return !(__x < __y); } 
88#endif // __cpp_lib_three_way_comparison 
89 
90 template<class _CharT, class _Traits> 
91 inline basic_ostream<_CharT, _Traits>& 
92 operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id) 
93 { 
94 if (__id == thread::id()) 
95 return __out << "thread::id of a non-executing thread"; 
96 else 
97 return __out << __id._M_thread; 
98 } 
99 
100#ifdef __cpp_lib_jthread 
101 
102 /// A thread that can be requested to stop and automatically joined. 
103 class jthread 
104 { 
105 public: 
106 using id = thread::id; 
107 using native_handle_type = thread::native_handle_type; 
108 
109 jthread() noexcept 
110 : _M_stop_source{nostopstate} 
111 { } 
112 
113 template<typename _Callable, typename... _Args, 
114 typename = enable_if_t<!is_same_v<remove_cvref_t<_Callable>, 
115 jthread>>> 
116 explicit 
117 jthread(_Callable&& __f, _Args&&... __args) 
118 : _M_thread{_S_create(_M_stop_source, std::forward<_Callable>(__f), 
119 std::forward<_Args>(__args)...)} 
120 { } 
121 
122 jthread(const jthread&) = delete; 
123 jthread(jthread&&) noexcept = default; 
124 
125 ~jthread() 
126 { 
127 if (joinable()) 
128 { 
129 request_stop(); 
130 join(); 
131 } 
132 } 
133 
134 jthread& 
135 operator=(const jthread&) = delete; 
136 
137 jthread& 
138 operator=(jthread&& __other) noexcept 
139 { 
140 std::jthread(std::move(__other)).swap(other&: *this); 
141 return *this; 
142 } 
143 
144 void 
145 swap(jthread& __other) noexcept 
146 { 
147 std::swap(a&: _M_stop_source, b&: __other._M_stop_source); 
148 std::swap(x&: _M_thread, y&: __other._M_thread); 
149 } 
150 
151 [[nodiscard]] bool 
152 joinable() const noexcept 
153 { 
154 return _M_thread.joinable(); 
155 } 
156 
157 void 
158 join() 
159 { 
160 _M_thread.join(); 
161 } 
162 
163 void 
164 detach() 
165 { 
166 _M_thread.detach(); 
167 } 
168 
169 [[nodiscard]] id 
170 get_id() const noexcept 
171 { 
172 return _M_thread.get_id(); 
173 } 
174 
175 [[nodiscard]] native_handle_type 
176 native_handle() 
177 { 
178 return _M_thread.native_handle(); 
179 } 
180 
181 [[nodiscard]] static unsigned 
182 hardware_concurrency() noexcept 
183 { 
184 return thread::hardware_concurrency(); 
185 } 
186 
187 [[nodiscard]] stop_source 
188 get_stop_source() noexcept 
189 { 
190 return _M_stop_source; 
191 } 
192 
193 [[nodiscard]] stop_token 
194 get_stop_token() const noexcept 
195 { 
196 return _M_stop_source.get_token(); 
197 } 
198 
199 bool request_stop() noexcept 
200 { 
201 return _M_stop_source.request_stop(); 
202 } 
203 
204 friend void swap(jthread& __lhs, jthread& __rhs) noexcept 
205 { 
206 __lhs.swap(other&: __rhs); 
207 } 
208 
209 private: 
210 template<typename _Callable, typename... _Args> 
211 static thread 
212 _S_create(stop_source& __ssrc, _Callable&& __f, _Args&&... __args) 
213 { 
214 if constexpr(is_invocable_v<decay_t<_Callable>, stop_token, 
215 decay_t<_Args>...>) 
216 return thread{std::forward<_Callable>(__f), __ssrc.get_token(), 
217 std::forward<_Args>(__args)...}; 
218 else 
219 { 
220 static_assert(is_invocable_v<decay_t<_Callable>, 
221 decay_t<_Args>...>, 
222 "std::thread arguments must be invocable after" 
223 " conversion to rvalues"); 
224 return thread{std::forward<_Callable>(__f), 
225 std::forward<_Args>(__args)...}; 
226 } 
227 } 
228 
229 stop_source _M_stop_source; 
230 thread _M_thread; 
231 }; 
232#endif // __cpp_lib_jthread 
233 
234 /// @} group threads 
235 
236_GLIBCXX_END_NAMESPACE_VERSION 
237} // namespace 
238#endif // C++11 
239#endif // _GLIBCXX_THREAD 
240