text: //
  // detail/event.hpp
  // ~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #ifndef ASIO_DETAIL_EVENT_HPP
  #define ASIO_DETAIL_EVENT_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include "asio/detail/config.hpp"
  
  #if !defined(ASIO_HAS_THREADS)
  # include "asio/detail/null_event.hpp"
  #elif defined(ASIO_WINDOWS)
  # include "asio/detail/win_event.hpp"
  #elif defined(ASIO_HAS_PTHREADS)
  # include "asio/detail/posix_event.hpp"
  #elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
  # include "asio/detail/std_event.hpp"
  #else
  # error Only Windows, POSIX and std::condition_variable are supported!
  #endif
  
  namespace asio {
  namespace detail {
  
  #if !defined(ASIO_HAS_THREADS)
  typedef null_event event;
  #elif defined(ASIO_WINDOWS)
  typedef win_event event;
  #elif defined(ASIO_HAS_PTHREADS)
  typedef posix_event event;
  #elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
  typedef std_event event;
  #endif
  
  } // namespace detail
  } // namespace asio
  
  #endif // ASIO_DETAIL_EVENT_HPP
  