Re: [Xenomai-help] Application broken 2.3.4 ---> 2.4.0

["Ignacio García Pérez" <iggarpe@domain.hid>]

>> 2.3.x: returns -ETIMEDOUT but schedules the task for immediate execution.
>>
>> 2.4.0: returns -ETIMEDOUT and *does not* schedule the task for immediate
>> execution.
>>
>> The more I think about it the mode I think this is a bug.
>>
>> I just can't think of a situation in which idate is in the past and it
>> makes sense *not scheduling* the task for immediate execution...
>>     
>
> Why not passing TM_NOW as an initial date if you want the task to be
> scheduled immediately instead of passing a date in the past ? It has
> always worked and still works with Xenomai 2.4.0.
>   
Let's suppose some event happens at time T0 which is recorded. Then, 
after some processing I'm reading to call rt_task_set_periodic, but a 
little delay has passed. If I use:

rt_task_set_periodic(&mytask, TM_NOW, period)

The periodic thread will be executed at:

T0+D    T0+D+period    T0+D+period*2    T0+D+period*3    ...

However, if I use rt_task_set_periodic(&mytask, recorded_time, period):

T0+D    T0+period    T0+period*2    T0+period*3

That is, only the first execution is affected by the delay D. I think 
this option is clearly superior.