[Discuss-gnuradio] implementing message ports on an OOT module

[Jason Matusiak]

I had originally asked this question on the USRP site, but it was 
recommended by someone from Ettus to post over here since there is a 
chance it is more of a GNURadio issue than USRP.

I am attempting to create an RFNoC block for the X310 and it works 
fine.  I then wanted to add a message port to the block to pass variable 
into it.  The message port shows up in GRC and the flowgraph runs fine 
as long as I leave the message port disconnected.  Once I try to connect 
something to it, I see the following error:
Could not find port: msg in:
rfnoc
system

Traceback (most recent call last):
  File "/home/jmat/rfnoc-multiaperture/examples/CPremoval.py", line 
253, in <module>
    main()
  File "/home/jmat/rfnoc-multiaperture/examples/CPremoval.py", line 
241, in main
    tb = top_block_cls()
  File "/home/jmat/rfnoc-multiaperture/examples/CPremoval.py", line 
196, in __init__
    self.msg_connect((self.foo_periodic_msg_source_0, 'out'), 
(self.multiaperture_cpremoval_0, 'msg'))
  File 
"/home/jmat/rfnoc/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py", 
line 59, in wrapped
    func(self, src.to_basic_block(), srcport, dst.to_basic_block(), 
dstport)
  File 
"/home/jmat/rfnoc/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py", 
line 131, in msg_connect
    self.primitive_msg_connect(*args)
  File 
"/home/jmat/rfnoc/lib/python2.7/dist-packages/gnuradio/gr/runtime_swig.py", 
line 3489, in primitive_msg_connect
    return _runtime_swig.top_block_sptr_primitive_msg_connect(self, *args)
RuntimeError: invalid msg port in connect() or disconnect()

>>> Done


I can't for the life of me figure out what GR "could not find."  I see 
other people with similar posts in the past, but I never found a good 
resolution.