Output not showing in GRC

GNU Radio
1

Hello guys,

As my first gnuradio block, I have built a block to multiply two complex
numbers using MATLAB library. I compiled my block and wrote a python
programme to test it and everything went very nicely. I used this c++
statement in the general_work method to see the output of the block:
std::cout << out[i]<< std::endl;
and indeed I can see the complex product for my inputs. However, when I
install my block in GRC, I connect the output to a file sink that stores
nothing! I also tried to plot the magnitude of the complex output and
nothing shows. The surprising part is that the output values of the
above
c++ statement are printed in the output area in GRC and this means that
my
c++ code is actually invoked.

I wonder if this has to do with library linking or not. Any
suggestions??

Thanks a lot!

Sam

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2

the file sink is probably not flushing to disk (common issue).

Try using a head block and the run to completion option and see what
happens. Upon completion, the file sink destructor will flush.

-Josh

3

hi josh,

Unfortunately, the solution didnt work. I also want to reiterate that I
used the graphical scope that failed as well.

Thanks

Sam

4

I’m afraid yes. These are the last two line in the general_work ()

consume_each(noutput_items);
return noutput_items;

I am actually suspicious about the makefile.am and library integration
stuff, can anybody check this for me please?

libgnuradio_mypackage_la_LDFLAGS =
$(NO_UNDEFINED)
-L$(MATLAB_ROOT)/runtime/glnx86

libgnuradio_arraycomms_la_LIBADD =
$(GNURADIO_CORE_LA)
-L/usr/lib -lmyfirstblock

where myfirstblock is a library generated in MATLAB

Cheers,

Sam

Johnathan C.-2 wrote:

Johnathan

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5

On Mon, May 31, 2010 at 14:57, Sammour [email protected] wrote:

However, when I
install my block in GRC, I connect the output to a file sink that stores
nothing! I also tried to plot the magnitude of the complex output and
nothing shows.

Are you returning the number of samples produced by your work function?

Johnathan