boost/libs/thread/test/test_8674.cpp

// Copyright (C) 2013 Vicente Botet
//
//  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)

#include <iostream>

#define USE_STD 0
#define USE_BOOST 1

#define USED_THREAD_API USE_BOOST
//#define USED_THREAD_API USE_STD

#if USED_THREAD_API == USE_BOOST

# define BOOST_THREAD_VERSION 4
# include <boost/thread/future.hpp>

  using boost::future;
  using boost::async;

#endif
#if USED_THREAD_API == USE_STD
# include <future>
  using std::future;
  using std::async;
#endif



future<void> do_something()
{
  auto result = async( []{ std::cout<< "A\n"; } );
  std::cout << "B\n";
  return result; // error here
}

int main()
{
  do_something().wait();
  std::cout << "Hello, World!" << std::endl;
  return 0;
}