// yield the processor to other environments #include void umain(int argc, char **argv) { int i; cprintf("Hello, I am environment %08x.\n", thisenv->env_id); for (i = 0; i < 5; i++) { sys_yield(); cprintf("Back in environment %08x, iteration %d.\n", thisenv->env_id, i); } cprintf("All done in environment %08x.\n", thisenv->env_id); }