[Xenomai-help] pthread_make_periodic_np initial start date

[Xenomai-help] pthread_make_periodic_np initial start date

[Steve Deiters]

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Is there a way to specify no initial delay when calling
pthread_make_periodic_np?  If I pass a value directly obtained from
clock_gettime, it will return a ETIMEDOUT error due to time passing
before I make the call.  I could add a small delay to the value obtained
from clock_gettime, but I would be concerned that due to other
happenings in the system, the absolute date may still have passed by the
time it gets around to calling pthread_make_periodic_np.

What I would be looking for I guess is what happens when I call
rt_task_set_periodic with an idate parameter of TM_NOW.  Is there any
way to simulate this behavior?

Thanks.


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Re: [Xenomai-help] pthread_make_periodic_np initial start date

[Gilles Chanteperdrix]

Steve Deiters wrote:
> Is there a way to specify no initial delay when calling
> pthread_make_periodic_np?  If I pass a value directly obtained from
> clock_gettime, it will return a ETIMEDOUT error due to time passing
> before I make the call.  I could add a small delay to the value obtained
> from clock_gettime, but I would be concerned that due to other
> happenings in the system, the absolute date may still have passed by the
> time it gets around to calling pthread_make_periodic_np.
> 
> What I would be looking for I guess is what happens when I call
> rt_task_set_periodic with an idate parameter of TM_NOW.  Is there any
> way to simulate this behavior?

pthread_make_periodic_np is a legacy from RTLinux. You should be using
clock_nanosleep instead.

That said, pthread_make_periodic_np internally uses the same service as
rt_task_set_periodic, and TM_NOW is just 0. So, you can probably pass a
timespec with tv_sec and tv_nsec both 0.


-- 
					    Gilles.