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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 #include <mutex>
  31
  32 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  33 #ifndef _GLIBCXX_HAVE_TLS
  34 namespace
  35 {
  36   std::mutex&
  37   get_once_mutex()
  38   {
  39     static std::mutex once_mutex;
  40     return once_mutex;
  41   }
  42 }
  43 #endif
  44
  45 namespace std
  46 {
  47   const defer_lock_t defer_lock = defer_lock_t();
  48   const try_to_lock_t try_to_lock = try_to_lock_t();
  49   const adopt_lock_t adopt_lock = adopt_lock_t();
  50
  51   const char*
  52   lock_error::what() const throw()
  53   { return "std::lock_error"; }
  54
  55 #ifdef _GLIBCXX_HAVE_TLS
  56   __thread void* __once_callable;
  57   __thread void (*__once_call)();
  58 #else
  59   // Explicit instantiation due to -fno-implicit-instantiation.
  60   template class function<void()>;
  61   function<void()> __once_functor;
  62
  63   unique_lock<mutex>&
  64   __get_once_functor_lock()
  65   {
  66     static unique_lock<mutex> once_functor_lock(get_once_mutex(), defer_lock);
  67     return once_functor_lock;
  68   }
  69 #endif
  70
  71   extern "C"
  72   {
  73     void __once_proxy()
  74     {
  75 #ifndef _GLIBCXX_HAVE_TLS
  76       function<void()> __once_call = std::move(__once_functor);
  77       __get_once_functor_lock().unlock();
  78 #endif
  79       __once_call();
  80     }
  81   }
  82 }
  83
  84 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1