thr_setprio(3THR) changes the priority of the thread, specified by tid, within the current process to the priority specified by newprio. (For POSIX threads, see "pthread_setschedparam(3THR)".)
#include <thread.h> int thr_setprio(thread_t tid, int newprio)
By default, threads are scheduled based on fixed priorities that range from zero, the least significant, to the largest integer. The tid will preempt lower-priority threads, and will yield to higher-priority threads.
thread_t tid; int ret; int newprio = 20; /* suspended thread creation */ ret = thr_create(NULL, NULL, func, arg, THR_SUSPEND, &tid); /* set the new priority of suspended child thread */ ret = thr_setprio(tid, newprio); /* suspended child thread starts executing with new priority */ ret = thr_continue(tid);