multithreading-exception-signal.cxx

#include <stdexcept>
#include <thread>
#include <future>
#include <iostream>
#include <boost/asio.hpp>

int main()
try
{
  auto future = std::async
  ( std::launch::async
  , [&]
    {
      try
      {
        throw std::runtime_error("answer is 42.");
      }
      catch(...)
      {
        std::cerr << "exception on an async thread, raise SIGINT.\n";
        raise(SIGINT);
        std::rethrow_exception(std::current_exception());
      }
    }
  );

  boost::asio::io_service aios;
  boost::asio::signal_set ss(aios, SIGINT, SIGTERM);
  ss.async_wait
  ( [&]
    ( const boost::system::error_code & e
    , int n
    )
    {
      if ( !e )
      {
        switch(n)
        {
          case SIGINT : std::cerr << "SIGINT"; break;
          case SIGTERM: std::cerr << "SIGTERM"; break;
          default: std::cerr << "SIG( " << n << ")";
        }
        std::cerr << "\n";
      }
      else
        std::cerr << "error_code is " << e << "\n";
    }
  );
  
  aios.run();

  future.get();
}
catch (const std::exception& e)
{
  std::cerr << "caught an std::exception, what: " << e.what() << "\n";
  return -1;
}
catch (...)
{
  std::cerr << "caught unknown exception.\n";
  return -2;
}

run result:

exception on an async thread, raise SIGINT.
SIGINT
caught an std::exception, what: answer is 42.