Message port connections in gr-blocks/examples/msg_passing

I’m trying to learn the message passing API by reviewing the examples in
gr-blocks/examples/msg_passing. Message ports are not connected upon
opening GRC (this seems to be a gnuradio-wide problem - same thing
happens with gr-ieee802-11). I know the workaround is to open each hier
block and build so that code gets put in ~/.grc_gnuradio. However, I’m
not sure how to hook up the ports as they were intended. Does anybody
have screen captures of strobe.grc, test_msg_hier.grc, and
test_msg_hier_topblock.grc with the ports connected correctly?

Thanks,
Sean

On Mon, Dec 16, 2013 at 4:02 PM, Nowlan, Sean
[email protected] wrote:

Thanks,
Sean

I wonder if the message connection problem is due to a fairly recent
change in how the message connections are displayed? We changed it
from a solid to a dashed line to make it easier to identify the
different types of connections. Hopefully, once the connections are
remade using the new code, it’ll stay that way. I’ll try to fix things
up on my end and push the changes.

Sebastian, do you have any comments on this?

Tom

Was offline this week…

I looked at the example in gr-blocks and this is not an issue with the
way connections are displayed. Sean, you should see some error messages
in the console detailing which connections (including their blocks and
ports) could not be made. That should help to reconstruct the original
connections.

In any case, the reason for these connections not been made is change of
the way message ports are identified within GRC. Up until recently a
numeric index (same as the stream ports) was used which caused problems
with using “nports” tags. Now, the message port name is used as key
because it is more consistent with the ‘connect’ method calls. This is
the root cause of what your experiencing.

I am a little surprised to hear that gr-ieee802-11 files are not working
either because it was Bastian who came up with the need to change
this…

Anyway, I will add a backward compatibility fix to resolve this.

Sebastian


Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Sebastian Koslowski
Research Associate

Kaiserstrae 12
Building 05.01
76131 Karlsruhe, Germany

Phone: +49 721 608-46275
Fax: +49 721 608-46071
Email: [email protected]
Web: http://www.cel.kit.edu/

KIT University of the State of Baden-Wuerttemberg and National
Research Center of the Helmholtz Association


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Hi,

On 19 Dec 2013, at 17:45, Koslowski, Sebastian (CEL)
[email protected] wrote:

I am a little surprised to hear that gr-ieee802-11 files are not working
either because it was Bastian who came up with the need to change this…

Im currently travelling and cant test it, but I updated my stuff and
tested it on several different PCs. So it should work.

The conversation with Sean about the broken connections was before the
changes to mainline. At that time I had a non-standard installation and
therefore my flow graphs did not work for out of the box. But that
should be fixed now.

Bastian

I created a patch to fix the issue of missing message connections. If
you want to help testing, see

https://github.com/gnuradio/gnuradio-wg-grc/tree/grc_fg_load_fix

Let me know, if this works for you. Also, the hier/ example in gr-blocks
had a minor bug. See:

https://github.com/gnuradio/gnuradio-wg-grc/tree/blocks_msg_example_fix

Sebastian


Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Sebastian Koslowski
Research Associate

Kaiserstrae 12
Building 05.01
76131 Karlsruhe, Germany

Phone: +49 721 608-46275
Fax: +49 721 608-46071
Email: [email protected]
Web: http://www.cel.kit.edu/

KIT University of the State of Baden-Wuerttemberg and National
Research Center of the Helmholtz Association