boost.spawn creates a new fiber and starts new stackful thread of execution. The spawn() function is a high-level wrapper over the boost.context library. This function enables programs to implement asynchronous logic in a synchronous manner. Suspending/resuming of the spawned fiber is controlled by boost.asio.
In contrast to boost.asio that uses the deprecated boost.coroutine library for its boost::asio::spawn() the implementation of boost.spawn is based only on boost.context.
boost.context requires C++11!