text: // future -*- C++ -*-
  
  // Copyright (C) 2009-2017 Free Software Foundation, Inc.
  //
  // This file is part of the GNU ISO C++ Library.  This library is free
  // software; you can redistribute it and/or modify it under the
  // terms of the GNU General Public License as published by the
  // Free Software Foundation; either version 3, or (at your option)
  // any later version.
  
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  // GNU General Public License for more details.
  
  // Under Section 7 of GPL version 3, you are granted additional
  // permissions described in the GCC Runtime Library Exception, version
  // 3.1, as published by the Free Software Foundation.
  
  // You should have received a copy of the GNU General Public License and
  // a copy of the GCC Runtime Library Exception along with this program;
  // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  // <http://www.gnu.org/licenses/>.
  
  #include <future>
  #include <bits/functexcept.h>
  
  namespace
  {
    struct future_error_category : public std::error_category
    {
      virtual const char*
      name() const noexcept
      { return "future"; }
  
      _GLIBCXX_DEFAULT_ABI_TAG
      virtual std::string message(int __ec) const
      {
        std::string __msg;
        switch (std::future_errc(__ec))
        {
        case std::future_errc::broken_promise:
            __msg = "Broken promise";
            break;
        case std::future_errc::future_already_retrieved:
            __msg = "Future already retrieved";
            break;
        case std::future_errc::promise_already_satisfied:
            __msg = "Promise already satisfied";
            break;
        case std::future_errc::no_state:
            __msg = "No associated state";
            break;
        default:
            __msg = "Unknown error";
            break;
        }
        return __msg;
      }
    };
  
    const future_error_category&
    __future_category_instance() noexcept
    {
      static const future_error_category __fec{};
      return __fec;
    }
  }
  
  namespace std _GLIBCXX_VISIBILITY(default)
  {
  _GLIBCXX_BEGIN_NAMESPACE_VERSION
  
    void
    __throw_future_error(int __i __attribute__((unused)))
    { _GLIBCXX_THROW_OR_ABORT(future_error(make_error_code(future_errc(__i)))); }
  
    const error_category& future_category() noexcept
    { return __future_category_instance(); }
  
    future_error::~future_error() noexcept { }
  
    const char*
    future_error::what() const noexcept { return logic_error::what(); }
  
  #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
    __future_base::_Result_base::_Result_base() = default;
  
    __future_base::_Result_base::~_Result_base() = default;
  
    void
    __future_base::_State_baseV2::_Make_ready::_S_run(void* p)
    {
      unique_ptr<_Make_ready> mr{static_cast<_Make_ready*>(p)};
      if (auto state = mr->_M_shared_state.lock())
        {
  	// Use release MO to synchronize with observers of the ready state.
  	state->_M_status._M_store_notify_all(_Status::__ready,
  	    memory_order_release);
        }
    }
  
    // defined in src/c++11/condition_variable.cc
    extern void
    __at_thread_exit(__at_thread_exit_elt* elt);
  
    void
    __future_base::_State_baseV2::_Make_ready::_M_set()
    {
      _M_cb = &_Make_ready::_S_run;
      __at_thread_exit(this);
    }
  #endif
  
  _GLIBCXX_END_NAMESPACE_VERSION
  } // namespace std
  