libstdc++-v3/src/c++11/future.cc

   1 // future -*- C++ -*-
   2
   3 // Copyright (C) 2009-2017 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 <future>
  26
  27 namespace
  28 {
  29   struct future_error_category : public std::error_category
  30   {
  31     virtual const char*
  32     name() const noexcept
  33     { return "future"; }
  34
  35     _GLIBCXX_DEFAULT_ABI_TAG
  36     virtual std::string message(int __ec) const
  37     {
  38       std::string __msg;
  39       switch (std::future_errc(__ec))
  40       {
  41       case std::future_errc::broken_promise:
  42           __msg = "Broken promise";
  43           break;
  44       case std::future_errc::future_already_retrieved:
  45           __msg = "Future already retrieved";
  46           break;
  47       case std::future_errc::promise_already_satisfied:
  48           __msg = "Promise already satisfied";
  49           break;
  50       case std::future_errc::no_state:
  51           __msg = "No associated state";
  52           break;
  53       default:
  54           __msg = "Unknown error";
  55           break;
  56       }
  57       return __msg;
  58     }
  59   };
  60
  61   const future_error_category&
  62   __future_category_instance() noexcept
  63   {
  64     static const future_error_category __fec{};
  65     return __fec;
  66   }
  67 }
  68
  69 namespace std _GLIBCXX_VISIBILITY(default)
  70 {
  71 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  72
  73   const error_category& future_category() noexcept
  74   { return __future_category_instance(); }
  75
  76   future_error::~future_error() noexcept { }
  77
  78   const char*
  79   future_error::what() const noexcept { return logic_error::what(); }
  80
  81 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  82   __future_base::_Result_base::_Result_base() = default;
  83
  84   __future_base::_Result_base::~_Result_base() = default;
  85
  86   void
  87   __future_base::_State_baseV2::_Make_ready::_S_run(void* p)
  88   {
  89     unique_ptr<_Make_ready> mr{static_cast<_Make_ready*>(p)};
  90     if (auto state = mr->_M_shared_state.lock())
  91       {
  92         // Use release MO to synchronize with observers of the ready state.
  93         state->_M_status._M_store_notify_all(_Status::__ready,
  94             memory_order_release);
  95       }
  96   }
  97
  98   // defined in src/c++11/condition_variable.cc
  99   extern void
 100   __at_thread_exit(__at_thread_exit_elt* elt);
 101
 102   void
 103   __future_base::_State_baseV2::_Make_ready::_M_set()
 104   {
 105     _M_cb = &_Make_ready::_S_run;
 106     __at_thread_exit(this);
 107   }
 108 #endif
 109
 110 _GLIBCXX_END_NAMESPACE_VERSION
 111 } // namespace std