Function sys_setpriority

components/lwp/lwp_syscall.c:1621–1649

* @brief Sets the priority of a process, process group, or user. * * This system call sets the priority of a process, process group, or user, depending * on the value of the `which` argument. The priority is used by the operating system * for scheduling processes. Lower numerical values represent higher priority in many * systems, and the priority range may be system-specific. * * @param wh

 * @see getpriority(), getpid(), getppid()
 */
sysret_t sys_setpriority(int which, id_t who, int prio)
{
    if (which == PRIO_PROCESS)
    {
        struct rt_lwp *lwp = RT_NULL;

        lwp_pid_lock_take();
        lwp = lwp_from_pid_locked(who);

        if (lwp && prio >= 0 && prio < RT_THREAD_PRIORITY_MAX)
        {
            rt_list_t *list;
            rt_thread_t thread;
            for (list = lwp->t_grp.next; list != &lwp->t_grp; list = list->next)
            {
                thread = rt_list_entry(list, struct rt_thread, sibling);
                rt_thread_control(thread, RT_THREAD_CTRL_RESET_PRIORITY, &prio);
            }
            lwp_pid_lock_release();
            return 0;
        }
        else
        {
            lwp_pid_lock_release();
        }
    }

    return -1;
}

/**
 * @brief Creates a semaphore.