libstdc++
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00001 // <thread> -*- C++ -*- 00002 00003 // Copyright (C) 2008-2016 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file include/thread 00026 * This is a Standard C++ Library header. 00027 */ 00028 00029 #ifndef _GLIBCXX_THREAD 00030 #define _GLIBCXX_THREAD 1 00031 00032 #pragma GCC system_header 00033 00034 #if __cplusplus < 201103L 00035 # include <bits/c++0x_warning.h> 00036 #else 00037 00038 #include <chrono> 00039 #include <functional> 00040 #include <memory> 00041 #include <cerrno> 00042 #include <bits/functexcept.h> 00043 #include <bits/functional_hash.h> 00044 #include <bits/gthr.h> 00045 00046 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 00047 00048 namespace std _GLIBCXX_VISIBILITY(default) 00049 { 00050 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00051 00052 /** 00053 * @defgroup threads Threads 00054 * @ingroup concurrency 00055 * 00056 * Classes for thread support. 00057 * @{ 00058 */ 00059 00060 /// thread 00061 class thread 00062 { 00063 public: 00064 // Abstract base class for types that wrap arbitrary functors to be 00065 // invoked in the new thread of execution. 00066 struct _State 00067 { 00068 virtual ~_State(); 00069 virtual void _M_run() = 0; 00070 }; 00071 using _State_ptr = unique_ptr<_State>; 00072 00073 typedef __gthread_t native_handle_type; 00074 00075 /// thread::id 00076 class id 00077 { 00078 native_handle_type _M_thread; 00079 00080 public: 00081 id() noexcept : _M_thread() { } 00082 00083 explicit 00084 id(native_handle_type __id) : _M_thread(__id) { } 00085 00086 private: 00087 friend class thread; 00088 friend class hash<thread::id>; 00089 00090 friend bool 00091 operator==(thread::id __x, thread::id __y) noexcept 00092 { 00093 // pthread_equal is undefined if either thread ID is not valid, so we 00094 // can't safely use __gthread_equal on default-constructed values (nor 00095 // the non-zero value returned by this_thread::get_id() for 00096 // single-threaded programs using GNU libc). Assume EqualityComparable. 00097 return __x._M_thread == __y._M_thread; 00098 } 00099 00100 friend bool 00101 operator<(thread::id __x, thread::id __y) noexcept 00102 { 00103 // Pthreads doesn't define any way to do this, so we just have to 00104 // assume native_handle_type is LessThanComparable. 00105 return __x._M_thread < __y._M_thread; 00106 } 00107 00108 template<class _CharT, class _Traits> 00109 friend basic_ostream<_CharT, _Traits>& 00110 operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id); 00111 }; 00112 00113 private: 00114 id _M_id; 00115 00116 public: 00117 thread() noexcept = default; 00118 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00119 // 2097. packaged_task constructors should be constrained 00120 thread(thread&) = delete; 00121 thread(const thread&) = delete; 00122 00123 thread(thread&& __t) noexcept 00124 { swap(__t); } 00125 00126 template<typename _Callable, typename... _Args> 00127 explicit 00128 thread(_Callable&& __f, _Args&&... __args) 00129 { 00130 #ifdef GTHR_ACTIVE_PROXY 00131 // Create a reference to pthread_create, not just the gthr weak symbol. 00132 auto __depend = reinterpret_cast<void(*)()>(&pthread_create); 00133 #else 00134 auto __depend = nullptr; 00135 #endif 00136 _M_start_thread(_S_make_state( 00137 std::__bind_simple(std::forward<_Callable>(__f), 00138 std::forward<_Args>(__args)...)), 00139 __depend); 00140 } 00141 00142 ~thread() 00143 { 00144 if (joinable()) 00145 std::terminate(); 00146 } 00147 00148 thread& operator=(const thread&) = delete; 00149 00150 thread& operator=(thread&& __t) noexcept 00151 { 00152 if (joinable()) 00153 std::terminate(); 00154 swap(__t); 00155 return *this; 00156 } 00157 00158 void 00159 swap(thread& __t) noexcept 00160 { std::swap(_M_id, __t._M_id); } 00161 00162 bool 00163 joinable() const noexcept 00164 { return !(_M_id == id()); } 00165 00166 void 00167 join(); 00168 00169 void 00170 detach(); 00171 00172 thread::id 00173 get_id() const noexcept 00174 { return _M_id; } 00175 00176 /** @pre thread is joinable 00177 */ 00178 native_handle_type 00179 native_handle() 00180 { return _M_id._M_thread; } 00181 00182 // Returns a value that hints at the number of hardware thread contexts. 00183 static unsigned int 00184 hardware_concurrency() noexcept; 00185 00186 private: 00187 template<typename _Callable> 00188 struct _State_impl : public _State 00189 { 00190 _Callable _M_func; 00191 00192 _State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f)) 00193 { } 00194 00195 void 00196 _M_run() { _M_func(); } 00197 }; 00198 00199 void 00200 _M_start_thread(_State_ptr, void (*)()); 00201 00202 template<typename _Callable> 00203 static _State_ptr 00204 _S_make_state(_Callable&& __f) 00205 { 00206 using _Impl = _State_impl<_Callable>; 00207 return _State_ptr{new _Impl{std::forward<_Callable>(__f)}}; 00208 } 00209 #if _GLIBCXX_THREAD_ABI_COMPAT 00210 public: 00211 struct _Impl_base; 00212 typedef shared_ptr<_Impl_base> __shared_base_type; 00213 struct _Impl_base 00214 { 00215 __shared_base_type _M_this_ptr; 00216 virtual ~_Impl_base() = default; 00217 virtual void _M_run() = 0; 00218 }; 00219 00220 private: 00221 void 00222 _M_start_thread(__shared_base_type, void (*)()); 00223 00224 void 00225 _M_start_thread(__shared_base_type); 00226 #endif 00227 }; 00228 00229 inline void 00230 swap(thread& __x, thread& __y) noexcept 00231 { __x.swap(__y); } 00232 00233 inline bool 00234 operator!=(thread::id __x, thread::id __y) noexcept 00235 { return !(__x == __y); } 00236 00237 inline bool 00238 operator<=(thread::id __x, thread::id __y) noexcept 00239 { return !(__y < __x); } 00240 00241 inline bool 00242 operator>(thread::id __x, thread::id __y) noexcept 00243 { return __y < __x; } 00244 00245 inline bool 00246 operator>=(thread::id __x, thread::id __y) noexcept 00247 { return !(__x < __y); } 00248 00249 // DR 889. 00250 /// std::hash specialization for thread::id. 00251 template<> 00252 struct hash<thread::id> 00253 : public __hash_base<size_t, thread::id> 00254 { 00255 size_t 00256 operator()(const thread::id& __id) const noexcept 00257 { return std::_Hash_impl::hash(__id._M_thread); } 00258 }; 00259 00260 template<class _CharT, class _Traits> 00261 inline basic_ostream<_CharT, _Traits>& 00262 operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id) 00263 { 00264 if (__id == thread::id()) 00265 return __out << "thread::id of a non-executing thread"; 00266 else 00267 return __out << __id._M_thread; 00268 } 00269 00270 _GLIBCXX_END_NAMESPACE_VERSION 00271 00272 /** @namespace std::this_thread 00273 * @brief ISO C++ 2011 entities sub-namespace for thread. 00274 * 30.3.2 Namespace this_thread. 00275 */ 00276 namespace this_thread 00277 { 00278 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00279 00280 /// get_id 00281 inline thread::id 00282 get_id() noexcept 00283 { 00284 #ifdef __GLIBC__ 00285 // For the GNU C library pthread_self() is usable without linking to 00286 // libpthread.so but returns 0, so we cannot use it in single-threaded 00287 // programs, because this_thread::get_id() != thread::id{} must be true. 00288 // We know that pthread_t is an integral type in the GNU C library. 00289 if (!__gthread_active_p()) 00290 return thread::id(1); 00291 #endif 00292 return thread::id(__gthread_self()); 00293 } 00294 00295 /// yield 00296 inline void 00297 yield() noexcept 00298 { 00299 #ifdef _GLIBCXX_USE_SCHED_YIELD 00300 __gthread_yield(); 00301 #endif 00302 } 00303 00304 void 00305 __sleep_for(chrono::seconds, chrono::nanoseconds); 00306 00307 /// sleep_for 00308 template<typename _Rep, typename _Period> 00309 inline void 00310 sleep_for(const chrono::duration<_Rep, _Period>& __rtime) 00311 { 00312 if (__rtime <= __rtime.zero()) 00313 return; 00314 auto __s = chrono::duration_cast<chrono::seconds>(__rtime); 00315 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s); 00316 #ifdef _GLIBCXX_USE_NANOSLEEP 00317 __gthread_time_t __ts = 00318 { 00319 static_cast<std::time_t>(__s.count()), 00320 static_cast<long>(__ns.count()) 00321 }; 00322 while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR) 00323 { } 00324 #else 00325 __sleep_for(__s, __ns); 00326 #endif 00327 } 00328 00329 /// sleep_until 00330 template<typename _Clock, typename _Duration> 00331 inline void 00332 sleep_until(const chrono::time_point<_Clock, _Duration>& __atime) 00333 { 00334 auto __now = _Clock::now(); 00335 if (_Clock::is_steady) 00336 { 00337 if (__now < __atime) 00338 sleep_for(__atime - __now); 00339 return; 00340 } 00341 while (__now < __atime) 00342 { 00343 sleep_for(__atime - __now); 00344 __now = _Clock::now(); 00345 } 00346 } 00347 00348 _GLIBCXX_END_NAMESPACE_VERSION 00349 } 00350 00351 // @} group threads 00352 00353 } // namespace 00354 00355 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00356 00357 #endif // C++11 00358 00359 #endif // _GLIBCXX_THREAD