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 thread(const thread&&) = delete; 00123 00124 thread(thread&& __t) noexcept 00125 { swap(__t); } 00126 00127 template<typename _Callable, typename... _Args> 00128 explicit 00129 thread(_Callable&& __f, _Args&&... __args) 00130 { 00131 #ifdef GTHR_ACTIVE_PROXY 00132 // Create a reference to pthread_create, not just the gthr weak symbol. 00133 auto __depend = reinterpret_cast<void(*)()>(&pthread_create); 00134 #else 00135 auto __depend = nullptr; 00136 #endif 00137 _M_start_thread(_S_make_state( 00138 std::__bind_simple(std::forward<_Callable>(__f), 00139 std::forward<_Args>(__args)...)), 00140 __depend); 00141 } 00142 00143 ~thread() 00144 { 00145 if (joinable()) 00146 std::terminate(); 00147 } 00148 00149 thread& operator=(const thread&) = delete; 00150 00151 thread& operator=(thread&& __t) noexcept 00152 { 00153 if (joinable()) 00154 std::terminate(); 00155 swap(__t); 00156 return *this; 00157 } 00158 00159 void 00160 swap(thread& __t) noexcept 00161 { std::swap(_M_id, __t._M_id); } 00162 00163 bool 00164 joinable() const noexcept 00165 { return !(_M_id == id()); } 00166 00167 void 00168 join(); 00169 00170 void 00171 detach(); 00172 00173 thread::id 00174 get_id() const noexcept 00175 { return _M_id; } 00176 00177 /** @pre thread is joinable 00178 */ 00179 native_handle_type 00180 native_handle() 00181 { return _M_id._M_thread; } 00182 00183 // Returns a value that hints at the number of hardware thread contexts. 00184 static unsigned int 00185 hardware_concurrency() noexcept; 00186 00187 private: 00188 template<typename _Callable> 00189 struct _State_impl : public _State 00190 { 00191 _Callable _M_func; 00192 00193 _State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f)) 00194 { } 00195 00196 void 00197 _M_run() { _M_func(); } 00198 }; 00199 00200 void 00201 _M_start_thread(_State_ptr, void (*)()); 00202 00203 template<typename _Callable> 00204 static _State_ptr 00205 _S_make_state(_Callable&& __f) 00206 { 00207 using _Impl = _State_impl<_Callable>; 00208 return _State_ptr{new _Impl{std::forward<_Callable>(__f)}}; 00209 } 00210 #if _GLIBCXX_THREAD_ABI_COMPAT 00211 public: 00212 struct _Impl_base; 00213 typedef shared_ptr<_Impl_base> __shared_base_type; 00214 struct _Impl_base 00215 { 00216 __shared_base_type _M_this_ptr; 00217 virtual ~_Impl_base() = default; 00218 virtual void _M_run() = 0; 00219 }; 00220 00221 private: 00222 void 00223 _M_start_thread(__shared_base_type, void (*)()); 00224 00225 void 00226 _M_start_thread(__shared_base_type); 00227 #endif 00228 }; 00229 00230 inline void 00231 swap(thread& __x, thread& __y) noexcept 00232 { __x.swap(__y); } 00233 00234 inline bool 00235 operator!=(thread::id __x, thread::id __y) noexcept 00236 { return !(__x == __y); } 00237 00238 inline bool 00239 operator<=(thread::id __x, thread::id __y) noexcept 00240 { return !(__y < __x); } 00241 00242 inline bool 00243 operator>(thread::id __x, thread::id __y) noexcept 00244 { return __y < __x; } 00245 00246 inline bool 00247 operator>=(thread::id __x, thread::id __y) noexcept 00248 { return !(__x < __y); } 00249 00250 // DR 889. 00251 /// std::hash specialization for thread::id. 00252 template<> 00253 struct hash<thread::id> 00254 : public __hash_base<size_t, thread::id> 00255 { 00256 size_t 00257 operator()(const thread::id& __id) const noexcept 00258 { return std::_Hash_impl::hash(__id._M_thread); } 00259 }; 00260 00261 template<class _CharT, class _Traits> 00262 inline basic_ostream<_CharT, _Traits>& 00263 operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id) 00264 { 00265 if (__id == thread::id()) 00266 return __out << "thread::id of a non-executing thread"; 00267 else 00268 return __out << __id._M_thread; 00269 } 00270 00271 _GLIBCXX_END_NAMESPACE_VERSION 00272 00273 /** @namespace std::this_thread 00274 * @brief ISO C++ 2011 entities sub-namespace for thread. 00275 * 30.3.2 Namespace this_thread. 00276 */ 00277 namespace this_thread 00278 { 00279 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00280 00281 /// get_id 00282 inline thread::id 00283 get_id() noexcept 00284 { 00285 #ifdef __GLIBC__ 00286 // For the GNU C library pthread_self() is usable without linking to 00287 // libpthread.so but returns 0, so we cannot use it in single-threaded 00288 // programs, because this_thread::get_id() != thread::id{} must be true. 00289 // We know that pthread_t is an integral type in the GNU C library. 00290 if (!__gthread_active_p()) 00291 return thread::id(1); 00292 #endif 00293 return thread::id(__gthread_self()); 00294 } 00295 00296 /// yield 00297 inline void 00298 yield() noexcept 00299 { 00300 #ifdef _GLIBCXX_USE_SCHED_YIELD 00301 __gthread_yield(); 00302 #endif 00303 } 00304 00305 void 00306 __sleep_for(chrono::seconds, chrono::nanoseconds); 00307 00308 /// sleep_for 00309 template<typename _Rep, typename _Period> 00310 inline void 00311 sleep_for(const chrono::duration<_Rep, _Period>& __rtime) 00312 { 00313 if (__rtime <= __rtime.zero()) 00314 return; 00315 auto __s = chrono::duration_cast<chrono::seconds>(__rtime); 00316 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s); 00317 #ifdef _GLIBCXX_USE_NANOSLEEP 00318 __gthread_time_t __ts = 00319 { 00320 static_cast<std::time_t>(__s.count()), 00321 static_cast<long>(__ns.count()) 00322 }; 00323 while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR) 00324 { } 00325 #else 00326 __sleep_for(__s, __ns); 00327 #endif 00328 } 00329 00330 /// sleep_until 00331 template<typename _Clock, typename _Duration> 00332 inline void 00333 sleep_until(const chrono::time_point<_Clock, _Duration>& __atime) 00334 { 00335 auto __now = _Clock::now(); 00336 if (_Clock::is_steady) 00337 { 00338 if (__now < __atime) 00339 sleep_for(__atime - __now); 00340 return; 00341 } 00342 while (__now < __atime) 00343 { 00344 sleep_for(__atime - __now); 00345 __now = _Clock::now(); 00346 } 00347 } 00348 00349 _GLIBCXX_END_NAMESPACE_VERSION 00350 } 00351 00352 // @} group threads 00353 00354 } // namespace 00355 00356 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00357 00358 #endif // C++11 00359 00360 #endif // _GLIBCXX_THREAD