Boost.Fiber allows to customize the scheduling algorithm by a user-defined implementation. A fiber-scheduler must implement interface sched_algorithm. Boost.Fiber provides scheduler round_robin.

void thread_fn() {
    my_fiber_scheduler mfs;
    boost::fibers::set_scheduling_algorithm( & mfs);
    ...
}

fiber_context

The fiber_context class is mostly supposed to be opaque. However, certain members are available for use by a custom scheduling algorithm.