contrib/gcc-4.4/libstdc++-v3/src/mutex.cc

   1 // mutex -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009 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 #include <mutex>
  26
  27 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  28 #ifndef _GLIBCXX_HAVE_TLS
  29 namespace
  30 {
  31   inline std::unique_lock<std::mutex>*&
  32   __get_once_functor_lock_ptr()
  33   {
  34     static std::unique_lock<std::mutex>* __once_functor_lock_ptr = 0;
  35     return __once_functor_lock_ptr;
  36   }
  37 }
  38 #endif
  39
  40 namespace std
  41 {
  42   const defer_lock_t defer_lock = defer_lock_t();
  43   const try_to_lock_t try_to_lock = try_to_lock_t();
  44   const adopt_lock_t adopt_lock = adopt_lock_t();
  45
  46   const char*
  47   lock_error::what() const throw()
  48   { return "std::lock_error"; }
  49
  50 #ifdef _GLIBCXX_HAVE_TLS
  51   __thread void* __once_callable;
  52   __thread void (*__once_call)();
  53 #else
  54   // Explicit instantiation due to -fno-implicit-instantiation.
  55   template class function<void()>;
  56   function<void()> __once_functor;
  57
  58   mutex&
  59   __get_once_mutex()
  60   {
  61     static mutex once_mutex;
  62     return once_mutex;
  63   }
  64
  65   // code linked against ABI 3.4.12 and later uses this
  66   void
  67   __set_once_functor_lock_ptr(unique_lock<mutex>* __ptr)
  68   {
  69     __get_once_functor_lock_ptr() = __ptr;
  70   }
  71
  72   // unsafe - retained for compatibility with ABI 3.4.11
  73   unique_lock<mutex>&
  74   __get_once_functor_lock()
  75   {
  76     static unique_lock<mutex> once_functor_lock(__get_once_mutex(), defer_lock);
  77     return once_functor_lock;
  78   }
  79 #endif
  80
  81   extern "C"
  82   {
  83     void __once_proxy()
  84     {
  85 #ifndef _GLIBCXX_HAVE_TLS
  86       function<void()> __once_call = std::move(__once_functor);
  87       if (unique_lock<mutex>* __lock = __get_once_functor_lock_ptr())
  88       {
  89         // caller is using new ABI and provided lock ptr
  90         __get_once_functor_lock_ptr() = 0;
  91         __lock->unlock();
  92       }
  93       else
  94         __get_once_functor_lock().unlock();  // global lock
  95 #endif
  96       __once_call();
  97     }
  98   }
  99 }
 100
 101 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1