CALLOUT_ACTIVE
atomic_clear_int(&cc->flags, CALLOUT_ACTIVE);
return ((cc->flags & CALLOUT_ACTIVE) ? 1 : 0);
atomic_set_int(&cc->flags, CALLOUT_ACTIVE);
atomic_set_int(&cc->flags, CALLOUT_ACTIVE);
atomic_clear_int(&cc->flags, CALLOUT_ACTIVE);