libstdc++
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00001 // <mutex> -*- C++ -*- 00002 00003 // Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 00004 // Free Software Foundation, Inc. 00005 // 00006 // This file is part of the GNU ISO C++ Library. This library is free 00007 // software; you can redistribute it and/or modify it under the 00008 // terms of the GNU General Public License as published by the 00009 // Free Software Foundation; either version 3, or (at your option) 00010 // any later version. 00011 00012 // This library is distributed in the hope that it will be useful, 00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 // GNU General Public License for more details. 00016 00017 // Under Section 7 of GPL version 3, you are granted additional 00018 // permissions described in the GCC Runtime Library Exception, version 00019 // 3.1, as published by the Free Software Foundation. 00020 00021 // You should have received a copy of the GNU General Public License and 00022 // a copy of the GCC Runtime Library Exception along with this program; 00023 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00024 // <http://www.gnu.org/licenses/>. 00025 00026 /** @file include/mutex 00027 * This is a Standard C++ Library header. 00028 */ 00029 00030 #ifndef _GLIBCXX_MUTEX 00031 #define _GLIBCXX_MUTEX 1 00032 00033 #pragma GCC system_header 00034 00035 #ifndef __GXX_EXPERIMENTAL_CXX0X__ 00036 # include <bits/c++0x_warning.h> 00037 #else 00038 00039 #include <tuple> 00040 #include <chrono> 00041 #include <exception> 00042 #include <type_traits> 00043 #include <functional> 00044 #include <system_error> 00045 #include <bits/functexcept.h> 00046 #include <bits/gthr.h> 00047 #include <bits/move.h> // for std::swap 00048 00049 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 00050 00051 namespace std _GLIBCXX_VISIBILITY(default) 00052 { 00053 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00054 00055 // Common base class for std::mutex and std::timed_mutex 00056 class __mutex_base 00057 { 00058 protected: 00059 typedef __gthread_mutex_t __native_type; 00060 00061 #ifdef __GTHREAD_MUTEX_INIT 00062 __native_type _M_mutex = __GTHREAD_MUTEX_INIT; 00063 00064 constexpr __mutex_base() noexcept = default; 00065 #else 00066 __native_type _M_mutex; 00067 00068 __mutex_base() noexcept 00069 { 00070 // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may) 00071 __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex); 00072 } 00073 00074 ~__mutex_base() noexcept { __gthread_mutex_destroy(&_M_mutex); } 00075 #endif 00076 00077 __mutex_base(const __mutex_base&) = delete; 00078 __mutex_base& operator=(const __mutex_base&) = delete; 00079 }; 00080 00081 // Common base class for std::recursive_mutex and std::timed_recursive_mutex 00082 class __recursive_mutex_base 00083 { 00084 protected: 00085 typedef __gthread_recursive_mutex_t __native_type; 00086 00087 __recursive_mutex_base(const __recursive_mutex_base&) = delete; 00088 __recursive_mutex_base& operator=(const __recursive_mutex_base&) = delete; 00089 00090 #ifdef __GTHREAD_RECURSIVE_MUTEX_INIT 00091 __native_type _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT; 00092 00093 __recursive_mutex_base() = default; 00094 #else 00095 __native_type _M_mutex; 00096 00097 __recursive_mutex_base() 00098 { 00099 // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may) 00100 __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex); 00101 } 00102 00103 ~__recursive_mutex_base() 00104 { _S_destroy(&_M_mutex); } 00105 00106 private: 00107 // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy 00108 // so we need to obtain a __gthread_mutex_t to destroy 00109 00110 // matches when there's only one mutex type 00111 template<typename _Rm> 00112 static 00113 typename enable_if<is_same<_Rm, __gthread_mutex_t>::value, void>::type 00114 _S_destroy(_Rm* __mx) 00115 { __gthread_mutex_destroy(__mx); } 00116 00117 // matches a recursive mutex with a member 'actual' 00118 template<typename _Rm> 00119 static typename enable_if<sizeof(&_Rm::actual), void>::type 00120 _S_destroy(_Rm* __mx) 00121 { __gthread_mutex_destroy(&__mx->actual); } 00122 00123 // matches a gthr-win32.h recursive mutex 00124 template<typename _Rm> 00125 static typename enable_if<sizeof(&_Rm::sema), void>::type 00126 _S_destroy(_Rm* __mx) 00127 { 00128 __gthread_mutex_t __tmp; 00129 _S_destroy_win32(&__tmp, __mx); 00130 } 00131 00132 template<typename _Mx, typename _Rm> 00133 static void 00134 _S_destroy_win32(_Mx* __mx, _Rm const* __rmx) 00135 { 00136 __mx->counter = __rmx->counter; 00137 __mx->sema = __rmx->sema; 00138 __gthread_mutex_destroy(__mx); 00139 } 00140 #endif 00141 }; 00142 00143 /** 00144 * @defgroup mutexes Mutexes 00145 * @ingroup concurrency 00146 * 00147 * Classes for mutex support. 00148 * @{ 00149 */ 00150 00151 /// mutex 00152 class mutex : private __mutex_base 00153 { 00154 public: 00155 typedef __native_type* native_handle_type; 00156 00157 #ifdef __GTHREAD_MUTEX_INIT 00158 constexpr 00159 #endif 00160 mutex() noexcept = default; 00161 ~mutex() = default; 00162 00163 mutex(const mutex&) = delete; 00164 mutex& operator=(const mutex&) = delete; 00165 00166 void 00167 lock() 00168 { 00169 int __e = __gthread_mutex_lock(&_M_mutex); 00170 00171 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 00172 if (__e) 00173 __throw_system_error(__e); 00174 } 00175 00176 bool 00177 try_lock() noexcept 00178 { 00179 // XXX EINVAL, EAGAIN, EBUSY 00180 return !__gthread_mutex_trylock(&_M_mutex); 00181 } 00182 00183 void 00184 unlock() 00185 { 00186 // XXX EINVAL, EAGAIN, EPERM 00187 __gthread_mutex_unlock(&_M_mutex); 00188 } 00189 00190 native_handle_type 00191 native_handle() 00192 { return &_M_mutex; } 00193 }; 00194 00195 /// recursive_mutex 00196 class recursive_mutex : private __recursive_mutex_base 00197 { 00198 public: 00199 typedef __native_type* native_handle_type; 00200 00201 recursive_mutex() = default; 00202 ~recursive_mutex() = default; 00203 00204 recursive_mutex(const recursive_mutex&) = delete; 00205 recursive_mutex& operator=(const recursive_mutex&) = delete; 00206 00207 void 00208 lock() 00209 { 00210 int __e = __gthread_recursive_mutex_lock(&_M_mutex); 00211 00212 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 00213 if (__e) 00214 __throw_system_error(__e); 00215 } 00216 00217 bool 00218 try_lock() noexcept 00219 { 00220 // XXX EINVAL, EAGAIN, EBUSY 00221 return !__gthread_recursive_mutex_trylock(&_M_mutex); 00222 } 00223 00224 void 00225 unlock() 00226 { 00227 // XXX EINVAL, EAGAIN, EBUSY 00228 __gthread_recursive_mutex_unlock(&_M_mutex); 00229 } 00230 00231 native_handle_type 00232 native_handle() 00233 { return &_M_mutex; } 00234 }; 00235 00236 #if _GTHREAD_USE_MUTEX_TIMEDLOCK 00237 /// timed_mutex 00238 class timed_mutex : private __mutex_base 00239 { 00240 #ifdef _GLIBCXX_USE_CLOCK_MONOTONIC 00241 typedef chrono::steady_clock __clock_t; 00242 #else 00243 typedef chrono::high_resolution_clock __clock_t; 00244 #endif 00245 00246 public: 00247 typedef __native_type* native_handle_type; 00248 00249 timed_mutex() = default; 00250 ~timed_mutex() = default; 00251 00252 timed_mutex(const timed_mutex&) = delete; 00253 timed_mutex& operator=(const timed_mutex&) = delete; 00254 00255 void 00256 lock() 00257 { 00258 int __e = __gthread_mutex_lock(&_M_mutex); 00259 00260 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 00261 if (__e) 00262 __throw_system_error(__e); 00263 } 00264 00265 bool 00266 try_lock() noexcept 00267 { 00268 // XXX EINVAL, EAGAIN, EBUSY 00269 return !__gthread_mutex_trylock(&_M_mutex); 00270 } 00271 00272 template <class _Rep, class _Period> 00273 bool 00274 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 00275 { return __try_lock_for_impl(__rtime); } 00276 00277 template <class _Clock, class _Duration> 00278 bool 00279 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 00280 { 00281 chrono::time_point<_Clock, chrono::seconds> __s = 00282 chrono::time_point_cast<chrono::seconds>(__atime); 00283 00284 chrono::nanoseconds __ns = 00285 chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 00286 00287 __gthread_time_t __ts = { 00288 static_cast<std::time_t>(__s.time_since_epoch().count()), 00289 static_cast<long>(__ns.count()) 00290 }; 00291 00292 return !__gthread_mutex_timedlock(&_M_mutex, &__ts); 00293 } 00294 00295 void 00296 unlock() 00297 { 00298 // XXX EINVAL, EAGAIN, EBUSY 00299 __gthread_mutex_unlock(&_M_mutex); 00300 } 00301 00302 native_handle_type 00303 native_handle() 00304 { return &_M_mutex; } 00305 00306 private: 00307 template<typename _Rep, typename _Period> 00308 typename enable_if< 00309 ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 00310 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 00311 { 00312 __clock_t::time_point __atime = __clock_t::now() 00313 + chrono::duration_cast<__clock_t::duration>(__rtime); 00314 00315 return try_lock_until(__atime); 00316 } 00317 00318 template <typename _Rep, typename _Period> 00319 typename enable_if< 00320 !ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 00321 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 00322 { 00323 __clock_t::time_point __atime = __clock_t::now() 00324 + ++chrono::duration_cast<__clock_t::duration>(__rtime); 00325 00326 return try_lock_until(__atime); 00327 } 00328 }; 00329 00330 /// recursive_timed_mutex 00331 class recursive_timed_mutex : private __recursive_mutex_base 00332 { 00333 #ifdef _GLIBCXX_USE_CLOCK_MONOTONIC 00334 typedef chrono::steady_clock __clock_t; 00335 #else 00336 typedef chrono::high_resolution_clock __clock_t; 00337 #endif 00338 00339 public: 00340 typedef __native_type* native_handle_type; 00341 00342 recursive_timed_mutex() = default; 00343 ~recursive_timed_mutex() = default; 00344 00345 recursive_timed_mutex(const recursive_timed_mutex&) = delete; 00346 recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete; 00347 00348 void 00349 lock() 00350 { 00351 int __e = __gthread_recursive_mutex_lock(&_M_mutex); 00352 00353 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 00354 if (__e) 00355 __throw_system_error(__e); 00356 } 00357 00358 bool 00359 try_lock() noexcept 00360 { 00361 // XXX EINVAL, EAGAIN, EBUSY 00362 return !__gthread_recursive_mutex_trylock(&_M_mutex); 00363 } 00364 00365 template <class _Rep, class _Period> 00366 bool 00367 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 00368 { return __try_lock_for_impl(__rtime); } 00369 00370 template <class _Clock, class _Duration> 00371 bool 00372 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 00373 { 00374 chrono::time_point<_Clock, chrono::seconds> __s = 00375 chrono::time_point_cast<chrono::seconds>(__atime); 00376 00377 chrono::nanoseconds __ns = 00378 chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 00379 00380 __gthread_time_t __ts = { 00381 static_cast<std::time_t>(__s.time_since_epoch().count()), 00382 static_cast<long>(__ns.count()) 00383 }; 00384 00385 return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts); 00386 } 00387 00388 void 00389 unlock() 00390 { 00391 // XXX EINVAL, EAGAIN, EBUSY 00392 __gthread_recursive_mutex_unlock(&_M_mutex); 00393 } 00394 00395 native_handle_type 00396 native_handle() 00397 { return &_M_mutex; } 00398 00399 private: 00400 template<typename _Rep, typename _Period> 00401 typename enable_if< 00402 ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 00403 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 00404 { 00405 __clock_t::time_point __atime = __clock_t::now() 00406 + chrono::duration_cast<__clock_t::duration>(__rtime); 00407 00408 return try_lock_until(__atime); 00409 } 00410 00411 template <typename _Rep, typename _Period> 00412 typename enable_if< 00413 !ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 00414 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 00415 { 00416 __clock_t::time_point __atime = __clock_t::now() 00417 + ++chrono::duration_cast<__clock_t::duration>(__rtime); 00418 00419 return try_lock_until(__atime); 00420 } 00421 }; 00422 #endif 00423 00424 /// Do not acquire ownership of the mutex. 00425 struct defer_lock_t { }; 00426 00427 /// Try to acquire ownership of the mutex without blocking. 00428 struct try_to_lock_t { }; 00429 00430 /// Assume the calling thread has already obtained mutex ownership 00431 /// and manage it. 00432 struct adopt_lock_t { }; 00433 00434 constexpr defer_lock_t defer_lock { }; 00435 constexpr try_to_lock_t try_to_lock { }; 00436 constexpr adopt_lock_t adopt_lock { }; 00437 00438 /// @brief Scoped lock idiom. 00439 // Acquire the mutex here with a constructor call, then release with 00440 // the destructor call in accordance with RAII style. 00441 template<typename _Mutex> 00442 class lock_guard 00443 { 00444 public: 00445 typedef _Mutex mutex_type; 00446 00447 explicit lock_guard(mutex_type& __m) : _M_device(__m) 00448 { _M_device.lock(); } 00449 00450 lock_guard(mutex_type& __m, adopt_lock_t) : _M_device(__m) 00451 { } // calling thread owns mutex 00452 00453 ~lock_guard() 00454 { _M_device.unlock(); } 00455 00456 lock_guard(const lock_guard&) = delete; 00457 lock_guard& operator=(const lock_guard&) = delete; 00458 00459 private: 00460 mutex_type& _M_device; 00461 }; 00462 00463 /// unique_lock 00464 template<typename _Mutex> 00465 class unique_lock 00466 { 00467 public: 00468 typedef _Mutex mutex_type; 00469 00470 unique_lock() noexcept 00471 : _M_device(0), _M_owns(false) 00472 { } 00473 00474 explicit unique_lock(mutex_type& __m) 00475 : _M_device(&__m), _M_owns(false) 00476 { 00477 lock(); 00478 _M_owns = true; 00479 } 00480 00481 unique_lock(mutex_type& __m, defer_lock_t) noexcept 00482 : _M_device(&__m), _M_owns(false) 00483 { } 00484 00485 unique_lock(mutex_type& __m, try_to_lock_t) 00486 : _M_device(&__m), _M_owns(_M_device->try_lock()) 00487 { } 00488 00489 unique_lock(mutex_type& __m, adopt_lock_t) 00490 : _M_device(&__m), _M_owns(true) 00491 { 00492 // XXX calling thread owns mutex 00493 } 00494 00495 template<typename _Clock, typename _Duration> 00496 unique_lock(mutex_type& __m, 00497 const chrono::time_point<_Clock, _Duration>& __atime) 00498 : _M_device(&__m), _M_owns(_M_device->try_lock_until(__atime)) 00499 { } 00500 00501 template<typename _Rep, typename _Period> 00502 unique_lock(mutex_type& __m, 00503 const chrono::duration<_Rep, _Period>& __rtime) 00504 : _M_device(&__m), _M_owns(_M_device->try_lock_for(__rtime)) 00505 { } 00506 00507 ~unique_lock() 00508 { 00509 if (_M_owns) 00510 unlock(); 00511 } 00512 00513 unique_lock(const unique_lock&) = delete; 00514 unique_lock& operator=(const unique_lock&) = delete; 00515 00516 unique_lock(unique_lock&& __u) noexcept 00517 : _M_device(__u._M_device), _M_owns(__u._M_owns) 00518 { 00519 __u._M_device = 0; 00520 __u._M_owns = false; 00521 } 00522 00523 unique_lock& operator=(unique_lock&& __u) noexcept 00524 { 00525 if(_M_owns) 00526 unlock(); 00527 00528 unique_lock(std::move(__u)).swap(*this); 00529 00530 __u._M_device = 0; 00531 __u._M_owns = false; 00532 00533 return *this; 00534 } 00535 00536 void 00537 lock() 00538 { 00539 if (!_M_device) 00540 __throw_system_error(int(errc::operation_not_permitted)); 00541 else if (_M_owns) 00542 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00543 else 00544 { 00545 _M_device->lock(); 00546 _M_owns = true; 00547 } 00548 } 00549 00550 bool 00551 try_lock() 00552 { 00553 if (!_M_device) 00554 __throw_system_error(int(errc::operation_not_permitted)); 00555 else if (_M_owns) 00556 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00557 else 00558 { 00559 _M_owns = _M_device->try_lock(); 00560 return _M_owns; 00561 } 00562 } 00563 00564 template<typename _Clock, typename _Duration> 00565 bool 00566 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 00567 { 00568 if (!_M_device) 00569 __throw_system_error(int(errc::operation_not_permitted)); 00570 else if (_M_owns) 00571 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00572 else 00573 { 00574 _M_owns = _M_device->try_lock_until(__atime); 00575 return _M_owns; 00576 } 00577 } 00578 00579 template<typename _Rep, typename _Period> 00580 bool 00581 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 00582 { 00583 if (!_M_device) 00584 __throw_system_error(int(errc::operation_not_permitted)); 00585 else if (_M_owns) 00586 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00587 else 00588 { 00589 _M_owns = _M_device->try_lock_for(__rtime); 00590 return _M_owns; 00591 } 00592 } 00593 00594 void 00595 unlock() 00596 { 00597 if (!_M_owns) 00598 __throw_system_error(int(errc::operation_not_permitted)); 00599 else if (_M_device) 00600 { 00601 _M_device->unlock(); 00602 _M_owns = false; 00603 } 00604 } 00605 00606 void 00607 swap(unique_lock& __u) noexcept 00608 { 00609 std::swap(_M_device, __u._M_device); 00610 std::swap(_M_owns, __u._M_owns); 00611 } 00612 00613 mutex_type* 00614 release() noexcept 00615 { 00616 mutex_type* __ret = _M_device; 00617 _M_device = 0; 00618 _M_owns = false; 00619 return __ret; 00620 } 00621 00622 bool 00623 owns_lock() const noexcept 00624 { return _M_owns; } 00625 00626 explicit operator bool() const noexcept 00627 { return owns_lock(); } 00628 00629 mutex_type* 00630 mutex() const noexcept 00631 { return _M_device; } 00632 00633 private: 00634 mutex_type* _M_device; 00635 bool _M_owns; // XXX use atomic_bool 00636 }; 00637 00638 /// Partial specialization for unique_lock objects. 00639 template<typename _Mutex> 00640 inline void 00641 swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept 00642 { __x.swap(__y); } 00643 00644 template<int _Idx> 00645 struct __unlock_impl 00646 { 00647 template<typename... _Lock> 00648 static void 00649 __do_unlock(tuple<_Lock&...>& __locks) 00650 { 00651 std::get<_Idx>(__locks).unlock(); 00652 __unlock_impl<_Idx - 1>::__do_unlock(__locks); 00653 } 00654 }; 00655 00656 template<> 00657 struct __unlock_impl<-1> 00658 { 00659 template<typename... _Lock> 00660 static void 00661 __do_unlock(tuple<_Lock&...>&) 00662 { } 00663 }; 00664 00665 template<typename _Lock> 00666 unique_lock<_Lock> 00667 __try_to_lock(_Lock& __l) 00668 { return unique_lock<_Lock>(__l, try_to_lock); } 00669 00670 template<int _Idx, bool _Continue = true> 00671 struct __try_lock_impl 00672 { 00673 template<typename... _Lock> 00674 static void 00675 __do_try_lock(tuple<_Lock&...>& __locks, int& __idx) 00676 { 00677 __idx = _Idx; 00678 auto __lock = __try_to_lock(std::get<_Idx>(__locks)); 00679 if (__lock.owns_lock()) 00680 { 00681 __try_lock_impl<_Idx + 1, _Idx + 2 < sizeof...(_Lock)>:: 00682 __do_try_lock(__locks, __idx); 00683 if (__idx == -1) 00684 __lock.release(); 00685 } 00686 } 00687 }; 00688 00689 template<int _Idx> 00690 struct __try_lock_impl<_Idx, false> 00691 { 00692 template<typename... _Lock> 00693 static void 00694 __do_try_lock(tuple<_Lock&...>& __locks, int& __idx) 00695 { 00696 __idx = _Idx; 00697 auto __lock = __try_to_lock(std::get<_Idx>(__locks)); 00698 if (__lock.owns_lock()) 00699 { 00700 __idx = -1; 00701 __lock.release(); 00702 } 00703 } 00704 }; 00705 00706 /** @brief Generic try_lock. 00707 * @param __l1 Meets Mutex requirements (try_lock() may throw). 00708 * @param __l2 Meets Mutex requirements (try_lock() may throw). 00709 * @param __l3 Meets Mutex requirements (try_lock() may throw). 00710 * @return Returns -1 if all try_lock() calls return true. Otherwise returns 00711 * a 0-based index corresponding to the argument that returned false. 00712 * @post Either all arguments are locked, or none will be. 00713 * 00714 * Sequentially calls try_lock() on each argument. 00715 */ 00716 template<typename _Lock1, typename _Lock2, typename... _Lock3> 00717 int 00718 try_lock(_Lock1& __l1, _Lock2& __l2, _Lock3&... __l3) 00719 { 00720 int __idx; 00721 auto __locks = std::tie(__l1, __l2, __l3...); 00722 __try 00723 { __try_lock_impl<0>::__do_try_lock(__locks, __idx); } 00724 __catch(...) 00725 { } 00726 return __idx; 00727 } 00728 00729 /** @brief Generic lock. 00730 * @param __l1 Meets Mutex requirements (try_lock() may throw). 00731 * @param __l2 Meets Mutex requirements (try_lock() may throw). 00732 * @param __l3 Meets Mutex requirements (try_lock() may throw). 00733 * @throw An exception thrown by an argument's lock() or try_lock() member. 00734 * @post All arguments are locked. 00735 * 00736 * All arguments are locked via a sequence of calls to lock(), try_lock() 00737 * and unlock(). If the call exits via an exception any locks that were 00738 * obtained will be released. 00739 */ 00740 template<typename _L1, typename _L2, typename ..._L3> 00741 void 00742 lock(_L1& __l1, _L2& __l2, _L3&... __l3) 00743 { 00744 while (true) 00745 { 00746 unique_lock<_L1> __first(__l1); 00747 int __idx; 00748 auto __locks = std::tie(__l2, __l3...); 00749 __try_lock_impl<0, sizeof...(_L3)>::__do_try_lock(__locks, __idx); 00750 if (__idx == -1) 00751 { 00752 __first.release(); 00753 return; 00754 } 00755 } 00756 } 00757 00758 /// once_flag 00759 struct once_flag 00760 { 00761 private: 00762 typedef __gthread_once_t __native_type; 00763 __native_type _M_once = __GTHREAD_ONCE_INIT; 00764 00765 public: 00766 /// Constructor 00767 constexpr once_flag() noexcept = default; 00768 00769 /// Deleted copy constructor 00770 once_flag(const once_flag&) = delete; 00771 /// Deleted assignment operator 00772 once_flag& operator=(const once_flag&) = delete; 00773 00774 template<typename _Callable, typename... _Args> 00775 friend void 00776 call_once(once_flag& __once, _Callable&& __f, _Args&&... __args); 00777 }; 00778 00779 #ifdef _GLIBCXX_HAVE_TLS 00780 extern __thread void* __once_callable; 00781 extern __thread void (*__once_call)(); 00782 00783 template<typename _Callable> 00784 inline void 00785 __once_call_impl() 00786 { 00787 (*(_Callable*)__once_callable)(); 00788 } 00789 #else 00790 extern function<void()> __once_functor; 00791 00792 extern void 00793 __set_once_functor_lock_ptr(unique_lock<mutex>*); 00794 00795 extern mutex& 00796 __get_once_mutex(); 00797 #endif 00798 00799 extern "C" void __once_proxy(void); 00800 00801 /// call_once 00802 template<typename _Callable, typename... _Args> 00803 void 00804 call_once(once_flag& __once, _Callable&& __f, _Args&&... __args) 00805 { 00806 #ifdef _GLIBCXX_HAVE_TLS 00807 auto __bound_functor = std::__bind_simple(std::forward<_Callable>(__f), 00808 std::forward<_Args>(__args)...); 00809 __once_callable = &__bound_functor; 00810 __once_call = &__once_call_impl<decltype(__bound_functor)>; 00811 #else 00812 unique_lock<mutex> __functor_lock(__get_once_mutex()); 00813 auto __callable = std::__bind_simple(std::forward<_Callable>(__f), 00814 std::forward<_Args>(__args)...); 00815 __once_functor = [&]() { __callable(); }; 00816 __set_once_functor_lock_ptr(&__functor_lock); 00817 #endif 00818 00819 int __e = __gthread_once(&(__once._M_once), &__once_proxy); 00820 00821 #ifndef _GLIBCXX_HAVE_TLS 00822 if (__functor_lock) 00823 __set_once_functor_lock_ptr(0); 00824 #endif 00825 00826 if (__e) 00827 __throw_system_error(__e); 00828 } 00829 00830 // @} group mutexes 00831 _GLIBCXX_END_NAMESPACE_VERSION 00832 } // namespace 00833 00834 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00835 00836 #endif // __GXX_EXPERIMENTAL_CXX0X__ 00837 00838 #endif // _GLIBCXX_MUTEX