Function async_getlines

example/cpp14/executors/async_2.cpp:40–62

// A function to asynchronously read multiple lines from an input stream.
template <class IoExecutor, class Handler>
void async_getlines(IoExecutor io_ex, std::istream& is, std::string init, Handler handler)
{
  // Track work for the I/O executor.
  auto io_work_ex = boost::asio::prefer(io_ex,
      execution::outstanding_work.tracked);

  // Track work for the handler's associated executor.
  auto handler_work_ex = boost::asio::prefer(
      get_associated_executor(handler, io_ex),
      execution::outstanding_work.tracked);

  // Use the associated executor for each operation in the composition.
  async_getline(io_work_ex, is,
      bind_executor(handler_work_ex,
        [io_work_ex, &is, lines=std::move(init), handler=std::move(handler)]
        (std::string line) mutable
        {
          if (line.empty())
            handler(lines);
          else
            async_getlines(io_work_ex, is, lines + line + "\n", std::move(handler));
        }));
}

int main()
{