Set the Thread Priority

In Solaris threads, a thread created with a priority other than the priority of its parents is created in SUSPEND mode. While suspended, the thread's priority is modified using the thr_setprio(3C) function call. After thr_setprio() completes, the thread resumes execution.

A higher priority thread receives precedence over lower priority threads with respect to synchronization object contention.

thr_setprio Syntax

thr_setprio(3C) 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 Syntax.

#include <thread.h>

int thr_setprio(thread_t tid, int newprio)

The range of valid priorities for a thread depends on its scheduling policy.

thread_t tid;
int ret;
int newprio = 20;

/* suspended thread creation */
ret = thr_create(NULL, NULL, func, arg, THR_SUSPENDED, &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);

thr_setprio Return Values

thr_setprio() returns 0 if successful. When any of the following conditions is detected, thr_setprio() fails and returns the corresponding value.

ESRCH

Description:

The value specified by tid does not refer to an existing thread.

EINVAL

Description:

The value of priority is invalid for the scheduling policy of the specified thread.

EPERM

Description:

The caller does not have the appropriate permission to set the priority to the value specified.