[Xenomai-help] rt_printf and file writing

[Xenomai-help] rt_printf and file writing

[nourry]

Hi all,

maybe another silly question but where is written string passed to rt_printf ?
My program compiled fine but nothing appears on the screen, the issue is that
i'm doing data acquisition and i need to check during progression values i get
(anyway i've been asked to print these values on the screen).

Another thing, in order to keep these data even if the computer may come to
crash, we would appreciate to save them in a file, is there a way to do so in
realtime ?

Thanks again for your work,
Antoine

Re: [Xenomai-help] rt_printf and file writing

[Gilles Chanteperdrix]

nourry@domain.hid wrote:
> Hi all,
> 
> maybe another silly question but where is written string passed to rt_printf ?
> My program compiled fine but nothing appears on the screen, the issue is that
> i'm doing data acquisition and i need to check during progression values i get
> (anyway i've been asked to print these values on the screen).
> 
> Another thing, in order to keep these data even if the computer may come to
> crash, we would appreciate to save them in a file, is there a way to do so in
> realtime ?

Printing on the screen or to a file uses Linux drivers, so is not a
real-time operation, at least up to now with Xenomai. What you can do is
get real-time tasks to use a buffering IPC of some sort to let a non
real-time task do the actual writing to file or to the screen.

This is what rt_printf does. So, maybe you do not see anything because
your real-time task is running all the time and does not let linux run?

-- 
                                                 Gilles.

Re: [Xenomai-help] rt_printf and file writing

[Gilles Chanteperdrix]

Antoine Nourry wrote:
> Gilles Chanteperdrix a écrit :
>> This is what rt_printf does. So, maybe you do not see anything because
>> your real-time task is running all the time and does not let linux run?
>>
>>   
> Yes, i did not try but this is the case (concerning my RT task) and may 
> be the answer, thanks again.
> 

Well, don't do that, you have to let linux run from time to time,
otherwise you risk crashes or other problems.

P.S: do not forget to CC the mailing list when answering.

-- 
					    Gilles.