Re: [Xenomai-help] Strange pipe behaviour

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

>>
>> 1- rt_pipe_receive returns with r >= 0.
>> 2- /* whatever */
>> 3- Message is freed using rt_pipe_free.
>> 4- Next call to rt_pipe_receive returns with r = -EINTR.
>>
>> The only explanation I could come up with is that when the pipe is
>> closed by the user mode process, the rt_pipe_receive tells the rt task
>> by returning -EINTR. Is this right?.
>
>
> Yes.
>
>  According to the docs, -EINTR is
>
>> only returned if rt_task_unblock() has been called...
>>
>
> Actually, this is what happened through the internal interface.
> driver::release(pipe) -> nucleus::unblock(sleepers_on_pipe)

Sure, but that behaviour is *extremely* confusing for a newbie (like
me). Should be described in the docs (this time I don't submit a patch
because I don't quite understand the pipe internals yet).

And anyway, I don't see the point in notifying the RT task that the
non-RT end has closed the pipe. Or, in other words, if we want to
provide such a notification, we should provide also opening notification.

By the way, where is the xnpipe_* API documentation? I could not find it
in the online docs (firefox downloads the file search.php when I try to
use the search feature).

>
>> Nacho.
>>
>>
>>
>>
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>
>