Re: [Discuss-gnuradio] Problem feeding garbage to GNU Radio

[Philip Balister]

On Sat, Oct 11, 2008 at 11:14 PM, Eric Blossom <address@hidden> wrote:
> On Sat, Oct 11, 2008 at 01:04:55PM -0400, Philip Balister wrote:
>> On Sat, Oct 11, 2008 at 12:06 PM, Eric Blossom <address@hidden> wrote:
>> > On Fri, Oct 10, 2008 at 02:59:33PM -0400, Philip Balister wrote:
>> >> I'm working on a flow graph that reads samples from a file and feeds
>> >> them to the wfm demod block. I managed to get this working, but along
>> >> the way I ran across a problem ....
>> >>
>> >> My data file is 16bit complex shorts in big-endian format. It looks
>> >> like the file source block reads data from the file and sends it to
>> >> the fm demod which is expecting a complex float data. I attempted a
>> >> quick test by using the original data file (wrong format) which caused
>> >> the flow graph to crash with a seg fault. After converting the data to
>> >> a complex float representation the flowgraph works.
>> >>
>> >> Do people view this as a problem? It seems like the file source block
>> >> should attempt  some form of sanity checking on incoming data. If you
>> >> aren't expecting a problem, I could see this being hard for people new
>> >> to GNU Radio to debug.
>> >>
>> >> Philip
>> >
>> > It shouldn't segfault regardless of the input.
>> >
>> > Can you send or post a link to the flow graph and the test data that
>> > reproduces the problem?
>> >
>> > A gdb stack trace would let us know where it's blowing up.
>> > From there the bug should be easy to find and fix.
>>
>> I've attached the flow graph.
>>
>> The data file is here:
>>
>> http://ossie.wireless.vt.edu/~balister/capture/npr_iq_sample.dat
>>
>> Right now I'm working through figuring out how many python modules are
>> needed to run the flow graph, if I have a chance I'll try and get a
>> stack trace. I'm assuming you gsb python and run the flow graph? Arg,
>
> You only need to make a two line change in your code to hookup gdb to
> the running python image.  See:
> http://www.gnu.org/software/gnuradio/doc/howto-write-a-block.html#debugging
>
>> how do I get the python interpreter to load and run top_block.py .....

Should this move to the gnuradio.org wiki so people searching for gdb
can find this information?

Philip