SCHED_RR in Classic API?

Joel Sherrill joel.sherrill at
Fri May 30 13:10:16 UTC 2003

Kamen Penev wrote:
> Joel Sherrill wrote:
> > So you can call pthread_XXX on a task created using the Classic API.
> > This would be the easiest way to get this scheduling mode.
> >
> >
> After successfully creating a classic task with:
>    status = rtems_task_create(Task_name[MON_TASKNUM],
>                               200,
>                               RTEMS_MINIMUM_STACK_SIZE *
>                               RTEMS_PREEMPT|RTEMS_TIMESLICE,
>                               RTEMS_FLOATING_POINT,
>                               &Task_id[MON_TASKNUM]);
>    assert (RTEMS_SUCCESSFUL == status);
> The following fails:
>    pstatus = pthread_setschedparam(Task_id[MON_TASKNUM],
>                                     SCHED_RR,
>                                     &xSteperPosixParams);
> pstatus is ESRCH, which was the result of _Objects_Get searching for the
> classic Task_id in _POSIX_Threads_Information (via _POSIX_Threads_Get)..
> What am I missing?

Nothing. It looks to me that the Classic API got this right and there
is a minor bug in the POSIX API.  The Classic API calls _Thread_Get()
to translate a task ID into a (Thread_Control *).  The POSIX API
should NOT have a _POSIX_Threads_get().  It should be calling
And then it would work.

As a simple solution to verify the idea beind the fix, change the
body of _POSIX_Threads_Get to call _Thread_Get instead of _Objects_Get.

> Kamen

Joel Sherrill, Ph.D.             Director of Research & Development
joel at                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
Support Available                (256) 722-9985

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