On Tue, Aug 21, 2018 at 9:32 PM Greg Gallagher <g...@embeddedgreg.com> wrote:
>
> HI,
> I"m not sure if I understand how you are using stream. Stream
> stores data in an internal buffer until the reciever wakes up and
> reads the data.
Yes I read this in the API description.
But how this is different from normal write.
I found the same behavior.
> Your telling read just to read one message, usually I
> loop through the messages until read blocks again.
Yes this way it works, but then what is the difference here with
normal read, if we keep reading the message at the same time.
> Are you trying to
> read all the messages you sent to the pipe using stream in a single
> read?
Yes, exactly.
I though that is the purpose of streaming a messages.
I just want to create a scenario in which rt_pipe_stream works but
rt_pipe_write cannot.
Hope to demonstrate this?
> -Greg
>
> On Tue, Aug 21, 2018 at 11:06 AM, Pintu Kumar <pintu.p...@gmail.com> wrote:
> > Hi,
> >
> > This is the technique I am using:
> >
> > struct pipe_message {
> > char value[32];
> > };
> >
> > volatile int terminate = 0;
> >
> > realtime_task()
> > {
> > ret = rt_pipe_bind(&mpipe, "pipe", TM_INFINITE);
> > while (!terminate) {
> > ret = rt_pipe_read(&mpipe, &msg, sizeof(msg), TM_INFINITE);
> > printf("%s: rt_pipe_read: value: %c\n", __func__, msg.value[i]);
> > ret = rt_pipe_stream(&mpipe, &msg, sizeof(msg));
> > i++;
> > }
> > rt_pipe_unbind(&mpipe);
> > pthread_cancel(t_reg);
> > }
> >
> > regular_thread(void *arg)
> > {
> > char string[] = "realtime";
> > sprintf(device, "/dev/rtp%d", minor);
> > fd = open(device, O_RDWR);
> > for (read char by char from a string) {
> > msg.value[i] = ch;
> > ret = write(fd, &msg, sizeof(msg));
> > usleep(SLEEP_INTERVAL * MILLI_SECOND);
> > i++;
> > }
> > terminate = 1;
> > ret = read(fd, &msg, sizeof(msg));
> > printf("%s: read: value: %s\n", __func__, msg.value);
> > }
> >
> > With this I want to read all the rt_pipe_stream message at once in regular
> > thread.
> > Is this the correct way to implement stream ?
> > Or, please suggest how to modify this code to make stream work, which
> > behavior should be different from normal rt_pipe_write.
> >
> > Currently, with this implement, only the first byte is getting printed after
> > the read, in regular thread.
> > I want the the whole stream of characters should be printed at once.
> >
> >
> > Thanks,
> > Pintu
> >
> > On Tue, Aug 21, 2018 at 1:39 PM Pintu Kumar <pintu.p...@gmail.com> wrote:
> >>
> >> Dear Greg,
> >>
> >> For your information, I already implemented sample application using
> >> message pipe read/write API over RTIPC.
> >> For the reference I saw lib/alchemy/testsuite/pipe-1.c
> >>
> >> But now I wanted to use rt_pipe_stream and understand how it work.
> >> Mainly what is the real difference between rt_pipe_write and
> >> rt_pipe_stream, and how to implement such difference.
> >> According to my experiment, both behaves almost the same for me.
> >>
> >> I have read the description about rt_pipe_stream in the documentation.
> >> I tried to implement the similar logic, but behavior is not same for me.
> >>
> >> My understanding is that:
> >> Regular thread keeps writing one by one char to rtipc, and the real-time
> >> task reads one char at a time. Then real-time task call rt_pipe_stream
> >> which keeps storing all the characters until read is called.
> >>
> >> Finally, when regular thread calls "read" then all the data from
> >> stream will be read by the regular thread at once.
> >>
> >> I implemented it in similar way, but in the end regular thread could
> >> read only one char (first char) in the end.
> >>
> >>
> >> Thanks,
> >> Pintu
> >> On Tue, Aug 21, 2018 at 12:12 AM Greg Gallagher <g...@embeddedgreg.com>
> >> wrote:
> >> >
> >> > On Mon, Aug 20, 2018 at 2:02 PM, Pintu Kumar <pintu.p...@gmail.com>
> >> > wrote:
> >> > > May be both.
> >> > > Specially I want to know how to use may use of rt_pipe_steam with a
> >> > > use case
> >> > > example.
> >> > >
> >> > >
> >> > > On Mon, 20 Aug 2018, 10:10 pm Greg Gallagher, <g...@embeddedgreg.com>
> >> > > wrote:
> >> > >>
> >> > >> On Mon, Aug 20, 2018 at 9:48 AM, Pintu Kumar <pintu.p...@gmail.com>
> >> > >> wrote:
> >> > >> > Dear Greg,
> >> > >> >
> >> > >> > If you have any idea can you please explain how rt_pipe_stream
> >> > >> > works
> >> > >> > with an example.
> >> > >> > I need to prepare a demo, to demonstrate the usefulness of
> >> > >> > rt_pipe_stream API.
> >> > >> >
> >> > >> >
> >> > >> > Thanks,
> >> > >> > Pintu
> >> > >> > On Fri, Aug 17, 2018 at 6:56 PM Pintu Kumar <pintu.p...@gmail.com>
> >> > >> > wrote:
> >> > >> >>
> >> > >> >> Hi,
> >> > >> >>
> >> > >> >> I wanted to understand how rt_pipe_stream works and how it can be
> >> > >> >> useful.
> >> > >> >> I wanted to create a demo application using it.
> >> > >> >> But currently I could not figure out how to make use of it.
> >> > >> >>
> >> > >> >> I saw a sample pipe application under:
> >> > >> >> lib/alchemy/testsuite/pipe-1.c.
> >> > >> >> Based on this I am trying to create a new application that uses
> >> > >> >> rt_pipe_stream.
> >> > >> >> The rt_pipe_stream is working fine, but I wanted to test the
> >> > >> >> scenario
> >> > >> >> based on its description.
> >> > >> >>
> >> > >> >> My understanding is that:
> >> > >> >> Regular thread keeps write one by one char to rtipc, and the
> >> > >> >> real-time
> >> > >> >> task reads one char at a time. Then real-time task call
> >> > >> >> rt_pipe_stream
> >> > >> >> which keeps storing the char.
> >> > >> >> Finally, when regular thread calls "read" then all the data from
> >> > >> >> stream will be read by the regular thread at once.
> >> > >> >>
> >> > >> >> Hope my understanding is correct.
> >> > >> >> I want to prepare a sample application for the same.
> >> > >> >>
> >> > >> >> If any reference for rt_pipe_stream is available please let me
> >> > >> >> know.
> >> > >> >>
> >> > >> >>
> >> > >> >> Thanks,
> >> > >> >> Pintu
> >> > >> >
> >> > >> > _______________________________________________
> >> > >> > Xenomai mailing list
> >> > >> > Xenomai@xenomai.org
> >> > >> > https://xenomai.org/mailman/listinfo/xenomai
> >> > >>
> >> > >> HI,
> >> > >> Do you want an explaination how they worked in cobalt or an
> >> > >> exaplaination of how to use them?
> >> > >>
> >> > >> Thanks
> >> > >>
> >> > >> Greg
> >> >
> >> > Start here:
> >> >
> >> >
> >> > https://xenomai.org/documentation/xenomai-3/html/xeno3prm/group__alchemy__pipe.html#ga29521cc898afa0069963964955167aa5
> >> >
> >> > I'll see what I can for an example.
> >> >
> >> > -Greg
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