On Tue, Jan 28, 2014 at 12:05 PM, Tom Rondeau <[email protected]> wrote:

> On Tue, Jan 28, 2014 at 11:10 AM, Jose Rodriguez
> <[email protected]> wrote:
> >
> > Hi,
> >
> > I am a beginner at Gnuradio and I am working on writing some simple
> graphs.
> > I am having a problem w. the block "Message Source".
> >
> > I got the block "Message Strobe" connected to "Message Source" (the goal
> is
> > to extract the data bytes and feed them to a "Packet Encoder" block).
> >
> > The graph builds OK but when run I get:
> >
> > Using Volk machine: avx_64_mmx_orc
> > Traceback (most recent call last):
> >   File "/home/joser/Desktop/xx/top_block.py", line 120, in <module>
> >     tb = top_block()
> >   File "/home/joser/Desktop/xx/top_block.py", line 72, in __init__
> >     self.blocks_message_source_0 =
> blocks.message_source(gr.sizeof_char*1,
> > blocks_message_source_0_msgq_in)
> > NameError: global name 'blocks_message_source_0_msgq_in' is not defined
> >
> >>>> Done
> >
> > Any idea what the problem could be?
>
> It's certainly not obvious from that error message, but what's going
> on is that you are using the two different message systems in GNU
> Radio. The message_source is designed to work with a special msg_queue
> concept while the message strobe block is part of the newer
> asynchronous message passing architecture. Notice how they are
> different colors and so don't belong together.
>
>
OK, yes they are different colors (light grey vs. dark grey), my mistake.
Quick question, what block can/should be used to extract the data in the
message generated by Message Strobe?


We should add some language to the message passing page in the manual
> to better explain this distinction.
>
> > I checked: http://gnuradio.org/doc/doxygen/page_msg_passing.html and at
> the
> > bottom is says to look at the examples in gr-blocks/examples/msg_passing
> but
> > I get missing link errors when I load these files in my setup.
> >
> > My setup is gnuradio 3.7.2.1 running in Ubuntu 12.04.4 LTS.
> >
> > thanks for any help,
> >
> > Jose Rodriguez
> > [email protected]
>
> What exactly do you mean by link errors? Are you talking about missing
> blocks in the GRC graph or when you run it, you are getting linking
> errors in the library? Neither of which should be happening on that
> release.
>
> Tom
>

By "missing link errors" I meant that when the grc file is loaded, some
blocks are not connected. For example, when I load
gr-blocks/examples/msg_passing/strobe.grc in the screen there are two
Message Strobe blocks whose output are not connected. Also I get the
following output:

Loading:
"/home/joser/gnuradio/gnuradio/gr-blocks/examples/msg_passing/strobe.grc"
>>> Error: Connection between blocks_message_strobe_0(0) and
blocks_message_debug_0(0) could not be made.
    source key "0" not in source block keys
>>> Error: Connection between blocks_message_strobe_0_0(0) and
blocks_pdu_to_tagged_stream_0(0) could not be made.
    source key "0" not in source block keys
>>> Error: Connection between blocks_tagged_stream_to_pdu_0(0) and
blocks_message_debug_0(2) could not be made.
    source key "0" not in source block keys
>>> Done

It could be my setup (I have reloaded Gnuradio several times, I have found
that there are many example grc files out there which is great, but often
they are based on 3.6. I tried to have both releases 3.6 and 3.7 installed
with no success). Anyway, thanks for the quick response.

Jose
[email protected]
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