1// <mutex> -*- C++ -*- 2 3// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 4// Free Software Foundation, Inc. 5// 6// This file is part of the GNU ISO C++ Library. This library is free 7// software; you can redistribute it and/or modify it under the 8// terms of the GNU General Public License as published by the 9// Free Software Foundation; either version 3, or (at your option) 10// any later version. 11 12// This library is distributed in the hope that it will be useful, 13// but WITHOUT ANY WARRANTY; without even the implied warranty of 14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15// GNU General Public License for more details. 16 17// Under Section 7 of GPL version 3, you are granted additional 18// permissions described in the GCC Runtime Library Exception, version 19// 3.1, as published by the Free Software Foundation. 20 21// You should have received a copy of the GNU General Public License and 22// a copy of the GCC Runtime Library Exception along with this program; 23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24// <http://www.gnu.org/licenses/>. 25 26/** @file include/mutex 27 * This is a Standard C++ Library header. 28 */ 29 30#ifndef _GLIBCXX_MUTEX 31#define _GLIBCXX_MUTEX 1 32 33#pragma GCC system_header 34 35#ifndef __GXX_EXPERIMENTAL_CXX0X__ 36# include <bits/c++0x_warning.h> 37#else 38 39#include <tuple> 40#include <chrono> 41#include <exception> 42#include <type_traits> 43#include <functional> 44#include <system_error> 45#include <bits/functexcept.h> 46#include <bits/gthr.h> 47#include <bits/move.h> // for std::swap 48 49#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 50 51namespace std _GLIBCXX_VISIBILITY(default) 52{ 53_GLIBCXX_BEGIN_NAMESPACE_VERSION 54 55 // Common base class for std::mutex and std::timed_mutex 56 class __mutex_base 57 { 58 protected: 59 typedef __gthread_mutex_t __native_type; 60 61#ifdef __GTHREAD_MUTEX_INIT 62 __native_type _M_mutex = __GTHREAD_MUTEX_INIT; 63 64 constexpr __mutex_base() noexcept = default; 65#else 66 __native_type _M_mutex; 67 68 __mutex_base() noexcept 69 { 70 // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may) 71 __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex); 72 } 73 74 ~__mutex_base() noexcept { __gthread_mutex_destroy(&_M_mutex); } 75#endif 76 77 __mutex_base(const __mutex_base&) = delete; 78 __mutex_base& operator=(const __mutex_base&) = delete; 79 }; 80 81 // Common base class for std::recursive_mutex and std::timed_recursive_mutex 82 class __recursive_mutex_base 83 { 84 protected: 85 typedef __gthread_recursive_mutex_t __native_type; 86 87 __recursive_mutex_base(const __recursive_mutex_base&) = delete; 88 __recursive_mutex_base& operator=(const __recursive_mutex_base&) = delete; 89 90#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT 91 __native_type _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT; 92 93 __recursive_mutex_base() = default; 94#else 95 __native_type _M_mutex; 96 97 __recursive_mutex_base() 98 { 99 // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may) 100 __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex); 101 } 102 103 ~__recursive_mutex_base() 104 { _S_destroy(&_M_mutex); } 105 106 private: 107 // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy 108 // so we need to obtain a __gthread_mutex_t to destroy 109 110 // matches when there's only one mutex type 111 template<typename _Rm> 112 static 113 typename enable_if<is_same<_Rm, __gthread_mutex_t>::value, void>::type 114 _S_destroy(_Rm* __mx) 115 { __gthread_mutex_destroy(__mx); } 116 117 // matches a recursive mutex with a member 'actual' 118 template<typename _Rm> 119 static typename enable_if<(bool)sizeof(&_Rm::actual), void>::type 120 _S_destroy(_Rm* __mx) 121 { __gthread_mutex_destroy(&__mx->actual); } 122 123 // matches a gthr-win32.h recursive mutex 124 template<typename _Rm> 125 static typename enable_if<(bool)sizeof(&_Rm::sema), void>::type 126 _S_destroy(_Rm* __mx) 127 { 128 __gthread_mutex_t __tmp; 129 _S_destroy_win32(&__tmp, __mx); 130 } 131 132 template<typename _Mx, typename _Rm> 133 static void 134 _S_destroy_win32(_Mx* __mx, _Rm const* __rmx) 135 { 136 __mx->counter = __rmx->counter; 137 __mx->sema = __rmx->sema; 138 __gthread_mutex_destroy(__mx); 139 } 140#endif 141 }; 142 143 /** 144 * @defgroup mutexes Mutexes 145 * @ingroup concurrency 146 * 147 * Classes for mutex support. 148 * @{ 149 */ 150 151 /// mutex 152 class mutex : private __mutex_base 153 { 154 public: 155 typedef __native_type* native_handle_type; 156 157#ifdef __GTHREAD_MUTEX_INIT 158 constexpr 159#endif 160 mutex() noexcept = default; 161 ~mutex() = default; 162 163 mutex(const mutex&) = delete; 164 mutex& operator=(const mutex&) = delete; 165 166 void 167 lock() 168 { 169 int __e = __gthread_mutex_lock(&_M_mutex); 170 171 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 172 if (__e) 173 __throw_system_error(__e); 174 } 175 176 bool 177 try_lock() noexcept 178 { 179 // XXX EINVAL, EAGAIN, EBUSY 180 return !__gthread_mutex_trylock(&_M_mutex); 181 } 182 183 void 184 unlock() 185 { 186 // XXX EINVAL, EAGAIN, EPERM 187 __gthread_mutex_unlock(&_M_mutex); 188 } 189 190 native_handle_type 191 native_handle() 192 { return &_M_mutex; } 193 }; 194 195 /// recursive_mutex 196 class recursive_mutex : private __recursive_mutex_base 197 { 198 public: 199 typedef __native_type* native_handle_type; 200 201 recursive_mutex() = default; 202 ~recursive_mutex() = default; 203 204 recursive_mutex(const recursive_mutex&) = delete; 205 recursive_mutex& operator=(const recursive_mutex&) = delete; 206 207 void 208 lock() 209 { 210 int __e = __gthread_recursive_mutex_lock(&_M_mutex); 211 212 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 213 if (__e) 214 __throw_system_error(__e); 215 } 216 217 bool 218 try_lock() noexcept 219 { 220 // XXX EINVAL, EAGAIN, EBUSY 221 return !__gthread_recursive_mutex_trylock(&_M_mutex); 222 } 223 224 void 225 unlock() 226 { 227 // XXX EINVAL, EAGAIN, EBUSY 228 __gthread_recursive_mutex_unlock(&_M_mutex); 229 } 230 231 native_handle_type 232 native_handle() 233 { return &_M_mutex; } 234 }; 235 236#if _GTHREAD_USE_MUTEX_TIMEDLOCK 237 /// timed_mutex 238 class timed_mutex : private __mutex_base 239 { 240#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC 241 typedef chrono::steady_clock __clock_t; 242#else 243 typedef chrono::high_resolution_clock __clock_t; 244#endif 245 246 public: 247 typedef __native_type* native_handle_type; 248 249 timed_mutex() = default; 250 ~timed_mutex() = default; 251 252 timed_mutex(const timed_mutex&) = delete; 253 timed_mutex& operator=(const timed_mutex&) = delete; 254 255 void 256 lock() 257 { 258 int __e = __gthread_mutex_lock(&_M_mutex); 259 260 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 261 if (__e) 262 __throw_system_error(__e); 263 } 264 265 bool 266 try_lock() noexcept 267 { 268 // XXX EINVAL, EAGAIN, EBUSY 269 return !__gthread_mutex_trylock(&_M_mutex); 270 } 271 272 template <class _Rep, class _Period> 273 bool 274 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 275 { return __try_lock_for_impl(__rtime); } 276 277 template <class _Clock, class _Duration> 278 bool 279 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 280 { 281 chrono::time_point<_Clock, chrono::seconds> __s = 282 chrono::time_point_cast<chrono::seconds>(__atime); 283 284 chrono::nanoseconds __ns = 285 chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 286 287 __gthread_time_t __ts = { 288 static_cast<std::time_t>(__s.time_since_epoch().count()), 289 static_cast<long>(__ns.count()) 290 }; 291 292 return !__gthread_mutex_timedlock(&_M_mutex, &__ts); 293 } 294 295 void 296 unlock() 297 { 298 // XXX EINVAL, EAGAIN, EBUSY 299 __gthread_mutex_unlock(&_M_mutex); 300 } 301 302 native_handle_type 303 native_handle() 304 { return &_M_mutex; } 305 306 private: 307 template<typename _Rep, typename _Period> 308 typename enable_if< 309 ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 310 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 311 { 312 __clock_t::time_point __atime = __clock_t::now() 313 + chrono::duration_cast<__clock_t::duration>(__rtime); 314 315 return try_lock_until(__atime); 316 } 317 318 template <typename _Rep, typename _Period> 319 typename enable_if< 320 !ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 321 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 322 { 323 __clock_t::time_point __atime = __clock_t::now() 324 + ++chrono::duration_cast<__clock_t::duration>(__rtime); 325 326 return try_lock_until(__atime); 327 } 328 }; 329 330 /// recursive_timed_mutex 331 class recursive_timed_mutex : private __recursive_mutex_base 332 { 333#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC 334 typedef chrono::steady_clock __clock_t; 335#else 336 typedef chrono::high_resolution_clock __clock_t; 337#endif 338 339 public: 340 typedef __native_type* native_handle_type; 341 342 recursive_timed_mutex() = default; 343 ~recursive_timed_mutex() = default; 344 345 recursive_timed_mutex(const recursive_timed_mutex&) = delete; 346 recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete; 347 348 void 349 lock() 350 { 351 int __e = __gthread_recursive_mutex_lock(&_M_mutex); 352 353 // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may) 354 if (__e) 355 __throw_system_error(__e); 356 } 357 358 bool 359 try_lock() noexcept 360 { 361 // XXX EINVAL, EAGAIN, EBUSY 362 return !__gthread_recursive_mutex_trylock(&_M_mutex); 363 } 364 365 template <class _Rep, class _Period> 366 bool 367 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 368 { return __try_lock_for_impl(__rtime); } 369 370 template <class _Clock, class _Duration> 371 bool 372 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 373 { 374 chrono::time_point<_Clock, chrono::seconds> __s = 375 chrono::time_point_cast<chrono::seconds>(__atime); 376 377 chrono::nanoseconds __ns = 378 chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 379 380 __gthread_time_t __ts = { 381 static_cast<std::time_t>(__s.time_since_epoch().count()), 382 static_cast<long>(__ns.count()) 383 }; 384 385 return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts); 386 } 387 388 void 389 unlock() 390 { 391 // XXX EINVAL, EAGAIN, EBUSY 392 __gthread_recursive_mutex_unlock(&_M_mutex); 393 } 394 395 native_handle_type 396 native_handle() 397 { return &_M_mutex; } 398 399 private: 400 template<typename _Rep, typename _Period> 401 typename enable_if< 402 ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 403 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 404 { 405 __clock_t::time_point __atime = __clock_t::now() 406 + chrono::duration_cast<__clock_t::duration>(__rtime); 407 408 return try_lock_until(__atime); 409 } 410 411 template <typename _Rep, typename _Period> 412 typename enable_if< 413 !ratio_less_equal<__clock_t::period, _Period>::value, bool>::type 414 __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime) 415 { 416 __clock_t::time_point __atime = __clock_t::now() 417 + ++chrono::duration_cast<__clock_t::duration>(__rtime); 418 419 return try_lock_until(__atime); 420 } 421 }; 422#endif 423 424 /// Do not acquire ownership of the mutex. 425 struct defer_lock_t { }; 426 427 /// Try to acquire ownership of the mutex without blocking. 428 struct try_to_lock_t { }; 429 430 /// Assume the calling thread has already obtained mutex ownership 431 /// and manage it. 432 struct adopt_lock_t { }; 433 434 constexpr defer_lock_t defer_lock { }; 435 constexpr try_to_lock_t try_to_lock { }; 436 constexpr adopt_lock_t adopt_lock { }; 437 438 /// @brief Scoped lock idiom. 439 // Acquire the mutex here with a constructor call, then release with 440 // the destructor call in accordance with RAII style. 441 template<typename _Mutex> 442 class lock_guard 443 { 444 public: 445 typedef _Mutex mutex_type; 446 447 explicit lock_guard(mutex_type& __m) : _M_device(__m) 448 { _M_device.lock(); } 449 450 lock_guard(mutex_type& __m, adopt_lock_t) : _M_device(__m) 451 { } // calling thread owns mutex 452 453 ~lock_guard() 454 { _M_device.unlock(); } 455 456 lock_guard(const lock_guard&) = delete; 457 lock_guard& operator=(const lock_guard&) = delete; 458 459 private: 460 mutex_type& _M_device; 461 }; 462 463 /// unique_lock 464 template<typename _Mutex> 465 class unique_lock 466 { 467 public: 468 typedef _Mutex mutex_type; 469 470 unique_lock() noexcept 471 : _M_device(0), _M_owns(false) 472 { } 473 474 explicit unique_lock(mutex_type& __m) 475 : _M_device(&__m), _M_owns(false) 476 { 477 lock(); 478 _M_owns = true; 479 } 480 481 unique_lock(mutex_type& __m, defer_lock_t) noexcept 482 : _M_device(&__m), _M_owns(false) 483 { } 484 485 unique_lock(mutex_type& __m, try_to_lock_t) 486 : _M_device(&__m), _M_owns(_M_device->try_lock()) 487 { } 488 489 unique_lock(mutex_type& __m, adopt_lock_t) 490 : _M_device(&__m), _M_owns(true) 491 { 492 // XXX calling thread owns mutex 493 } 494 495 template<typename _Clock, typename _Duration> 496 unique_lock(mutex_type& __m, 497 const chrono::time_point<_Clock, _Duration>& __atime) 498 : _M_device(&__m), _M_owns(_M_device->try_lock_until(__atime)) 499 { } 500 501 template<typename _Rep, typename _Period> 502 unique_lock(mutex_type& __m, 503 const chrono::duration<_Rep, _Period>& __rtime) 504 : _M_device(&__m), _M_owns(_M_device->try_lock_for(__rtime)) 505 { } 506 507 ~unique_lock() 508 { 509 if (_M_owns) 510 unlock(); 511 } 512 513 unique_lock(const unique_lock&) = delete; 514 unique_lock& operator=(const unique_lock&) = delete; 515 516 unique_lock(unique_lock&& __u) noexcept 517 : _M_device(__u._M_device), _M_owns(__u._M_owns) 518 { 519 __u._M_device = 0; 520 __u._M_owns = false; 521 } 522 523 unique_lock& operator=(unique_lock&& __u) noexcept 524 { 525 if(_M_owns) 526 unlock(); 527 528 unique_lock(std::move(__u)).swap(*this); 529 530 __u._M_device = 0; 531 __u._M_owns = false; 532 533 return *this; 534 } 535 536 void 537 lock() 538 { 539 if (!_M_device) 540 __throw_system_error(int(errc::operation_not_permitted)); 541 else if (_M_owns) 542 __throw_system_error(int(errc::resource_deadlock_would_occur)); 543 else 544 { 545 _M_device->lock(); 546 _M_owns = true; 547 } 548 } 549 550 bool 551 try_lock() 552 { 553 if (!_M_device) 554 __throw_system_error(int(errc::operation_not_permitted)); 555 else if (_M_owns) 556 __throw_system_error(int(errc::resource_deadlock_would_occur)); 557 else 558 { 559 _M_owns = _M_device->try_lock(); 560 return _M_owns; 561 } 562 } 563 564 template<typename _Clock, typename _Duration> 565 bool 566 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 567 { 568 if (!_M_device) 569 __throw_system_error(int(errc::operation_not_permitted)); 570 else if (_M_owns) 571 __throw_system_error(int(errc::resource_deadlock_would_occur)); 572 else 573 { 574 _M_owns = _M_device->try_lock_until(__atime); 575 return _M_owns; 576 } 577 } 578 579 template<typename _Rep, typename _Period> 580 bool 581 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 582 { 583 if (!_M_device) 584 __throw_system_error(int(errc::operation_not_permitted)); 585 else if (_M_owns) 586 __throw_system_error(int(errc::resource_deadlock_would_occur)); 587 else 588 { 589 _M_owns = _M_device->try_lock_for(__rtime); 590 return _M_owns; 591 } 592 } 593 594 void 595 unlock() 596 { 597 if (!_M_owns) 598 __throw_system_error(int(errc::operation_not_permitted)); 599 else if (_M_device) 600 { 601 _M_device->unlock(); 602 _M_owns = false; 603 } 604 } 605 606 void 607 swap(unique_lock& __u) noexcept 608 { 609 std::swap(_M_device, __u._M_device); 610 std::swap(_M_owns, __u._M_owns); 611 } 612 613 mutex_type* 614 release() noexcept 615 { 616 mutex_type* __ret = _M_device; 617 _M_device = 0; 618 _M_owns = false; 619 return __ret; 620 } 621 622 bool 623 owns_lock() const noexcept 624 { return _M_owns; } 625 626 explicit operator bool() const noexcept 627 { return owns_lock(); } 628 629 mutex_type* 630 mutex() const noexcept 631 { return _M_device; } 632 633 private: 634 mutex_type* _M_device; 635 bool _M_owns; // XXX use atomic_bool 636 }; 637 638 /// Partial specialization for unique_lock objects. 639 template<typename _Mutex> 640 inline void 641 swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept 642 { __x.swap(__y); } 643 644 template<int _Idx> 645 struct __unlock_impl 646 { 647 template<typename... _Lock> 648 static void 649 __do_unlock(tuple<_Lock&...>& __locks) 650 { 651 std::get<_Idx>(__locks).unlock(); 652 __unlock_impl<_Idx - 1>::__do_unlock(__locks); 653 } 654 }; 655 656 template<> 657 struct __unlock_impl<-1> 658 { 659 template<typename... _Lock> 660 static void 661 __do_unlock(tuple<_Lock&...>&) 662 { } 663 }; 664 665 template<typename _Lock> 666 unique_lock<_Lock> 667 __try_to_lock(_Lock& __l) 668 { return unique_lock<_Lock>(__l, try_to_lock); } 669 670 template<int _Idx, bool _Continue = true> 671 struct __try_lock_impl 672 { 673 template<typename... _Lock> 674 static void 675 __do_try_lock(tuple<_Lock&...>& __locks, int& __idx) 676 { 677 __idx = _Idx; 678 auto __lock = __try_to_lock(std::get<_Idx>(__locks)); 679 if (__lock.owns_lock()) 680 { 681 __try_lock_impl<_Idx + 1, _Idx + 2 < sizeof...(_Lock)>:: 682 __do_try_lock(__locks, __idx); 683 if (__idx == -1) 684 __lock.release(); 685 } 686 } 687 }; 688 689 template<int _Idx> 690 struct __try_lock_impl<_Idx, false> 691 { 692 template<typename... _Lock> 693 static void 694 __do_try_lock(tuple<_Lock&...>& __locks, int& __idx) 695 { 696 __idx = _Idx; 697 auto __lock = __try_to_lock(std::get<_Idx>(__locks)); 698 if (__lock.owns_lock()) 699 { 700 __idx = -1; 701 __lock.release(); 702 } 703 } 704 }; 705 706 /** @brief Generic try_lock. 707 * @param __l1 Meets Mutex requirements (try_lock() may throw). 708 * @param __l2 Meets Mutex requirements (try_lock() may throw). 709 * @param __l3 Meets Mutex requirements (try_lock() may throw). 710 * @return Returns -1 if all try_lock() calls return true. Otherwise returns 711 * a 0-based index corresponding to the argument that returned false. 712 * @post Either all arguments are locked, or none will be. 713 * 714 * Sequentially calls try_lock() on each argument. 715 */ 716 template<typename _Lock1, typename _Lock2, typename... _Lock3> 717 int 718 try_lock(_Lock1& __l1, _Lock2& __l2, _Lock3&... __l3) 719 { 720 int __idx; 721 auto __locks = std::tie(__l1, __l2, __l3...); 722 __try 723 { __try_lock_impl<0>::__do_try_lock(__locks, __idx); } 724 __catch(...) 725 { } 726 return __idx; 727 } 728 729 /** @brief Generic lock. 730 * @param __l1 Meets Mutex requirements (try_lock() may throw). 731 * @param __l2 Meets Mutex requirements (try_lock() may throw). 732 * @param __l3 Meets Mutex requirements (try_lock() may throw). 733 * @throw An exception thrown by an argument's lock() or try_lock() member. 734 * @post All arguments are locked. 735 * 736 * All arguments are locked via a sequence of calls to lock(), try_lock() 737 * and unlock(). If the call exits via an exception any locks that were 738 * obtained will be released. 739 */ 740 template<typename _L1, typename _L2, typename ..._L3> 741 void 742 lock(_L1& __l1, _L2& __l2, _L3&... __l3) 743 { 744 while (true) 745 { 746 unique_lock<_L1> __first(__l1); 747 int __idx; 748 auto __locks = std::tie(__l2, __l3...); 749 __try_lock_impl<0, sizeof...(_L3)>::__do_try_lock(__locks, __idx); 750 if (__idx == -1) 751 { 752 __first.release(); 753 return; 754 } 755 } 756 } 757 758 /// once_flag 759 struct once_flag 760 { 761 private: 762 typedef __gthread_once_t __native_type; 763 __native_type _M_once = __GTHREAD_ONCE_INIT; 764 765 public: 766 /// Constructor 767 constexpr once_flag() noexcept = default; 768 769 /// Deleted copy constructor 770 once_flag(const once_flag&) = delete; 771 /// Deleted assignment operator 772 once_flag& operator=(const once_flag&) = delete; 773 774 template<typename _Callable, typename... _Args> 775 friend void 776 call_once(once_flag& __once, _Callable&& __f, _Args&&... __args); 777 }; 778 779#ifdef _GLIBCXX_HAVE_TLS 780 extern __thread void* __once_callable; 781 extern __thread void (*__once_call)(); 782 783 template<typename _Callable> 784 inline void 785 __once_call_impl() 786 { 787 (*(_Callable*)__once_callable)(); 788 } 789#else 790 extern function<void()> __once_functor; 791 792 extern void 793 __set_once_functor_lock_ptr(unique_lock<mutex>*); 794 795 extern mutex& 796 __get_once_mutex(); 797#endif 798 799 extern "C" void __once_proxy(void); 800 801 /// call_once 802 template<typename _Callable, typename... _Args> 803 void 804 call_once(once_flag& __once, _Callable&& __f, _Args&&... __args) 805 { 806#ifdef _GLIBCXX_HAVE_TLS 807 auto __bound_functor = std::__bind_simple(std::forward<_Callable>(__f), 808 std::forward<_Args>(__args)...); 809 __once_callable = &__bound_functor; 810 __once_call = &__once_call_impl<decltype(__bound_functor)>; 811#else 812 unique_lock<mutex> __functor_lock(__get_once_mutex()); 813 auto __callable = std::__bind_simple(std::forward<_Callable>(__f), 814 std::forward<_Args>(__args)...); 815 __once_functor = [&]() { __callable(); }; 816 __set_once_functor_lock_ptr(&__functor_lock); 817#endif 818 819 int __e = __gthread_once(&(__once._M_once), &__once_proxy); 820 821#ifndef _GLIBCXX_HAVE_TLS 822 if (__functor_lock) 823 __set_once_functor_lock_ptr(0); 824#endif 825 826 if (__e) 827 __throw_system_error(__e); 828 } 829 830 // @} group mutexes 831_GLIBCXX_END_NAMESPACE_VERSION 832} // namespace 833 834#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 835 836#endif // __GXX_EXPERIMENTAL_CXX0X__ 837 838#endif // _GLIBCXX_MUTEX 839