Re: [Discuss-gnuradio] Question on how to derive a class in an out-of-tree module based on a gnuradio class

[Bastian Bloessl]

Hi,

I did that in gr-ieee802-11 and IIRC I had to define GR_API in the swig config

https://github.com/bastibl/gr-ieee802-11/blob/master/swig/ieee802_11_swig.i#L18

Hope that helps,
Bastian

On 07 Oct 2014, at 11:27, Marcus Müller <address@hidden> wrote:

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> .... I should pay closer attention; sorry!
> 
> On 07.10.2014 11:16, Martin Braun wrote:
>> On 10/07/2014 09:54 AM, Marcus Müller wrote:
>>> This looks like a linker error. In your main CMakeList.txt, you
>>> have to add DIGITAL to the line containing
>>> 
>>> set(GR_REQUIRED_COMPONENTS ...
>> 
>> The OP mentioned he'd already done that, but I still agree with
>> your suspicion. It's actually more likely some SWIG/linking issue.
>> 
>> Are you referencing the correct header files in your SWIG file?
>> 
>> M
>> 
>> 
>> 
>> 
>>> If you already have that, sometimes make clean helps, when for
>>> some reason linker/ccache/black magic involving CMake failed.
>>> 
>>> Greetings, Marcus
>>> 
>>> On 07.10.2014 03:58, Zhe Feng wrote:
>>>> Dear all,
>>>> 
>>>> I'm trying to derive a *packet_header2* class in my own OOT
>>>> module based on *gr::digital::packet_header_default*. I
>>>> followed the way in *packet_heade_ofdm*  of gr-digital and made
>>>> packet_header2.h and packet_header2.cc in my own OOT module.
>>>> 
>>>> But when I tried to import my_oot in python, it returned an
>>>> undefined symbol error like this:
>>>> 
>>>> Traceback (most recent call last): File "<stdin>", line 1, in
>>>> <module> File
>>>> "/usr/local/lib/python2.7/dist-packages/my_oot/__init__.py",
>>>> line 45, in <module> from my_oot_swig import * File
>>>> "/usr/local/lib/python2.7/dist-packages/my_oot/my_oot_cdma.py",
>>>> line 26, in <module> _my_oot_swig = swig_import_helper() File
>>>> "/usr/local/lib/python2.7/dist-packages/cdma/cdma_swig.py",
>>>> line 22, in swig_import_helper _mod =
>>>> imp.load_module('_my_oot_swig', fp, pathname, description) 
>>>> ImportError: /usr/local/lib/libgnuradio-my_oot.so: undefined
>>>> symbol: _ZTIN2gr7digital21packet_header_defaultE
>>>> 
>>>> I searched the list and found a previous answered question
>>>> below 
>>>> http://gnuradio.4.n7.nabble.com/so-undefined-symbol-ZN2gr6blocks12count-bits16E-td46270.html
>>>> 
>>>> 
>>>> 
> where Marcus suggested editing the CMakeList.txt files by adding the module
>>>> I needed. So I added
>>>> 
>>>> *set(GR_REQUIRED_COMPONENTS RUNTIME DIGITAL)*  in
>>>> CMakeLists.txt.
>>>> 
>>>> and then. This above error disappeared when I import my_oot
>>>> again in python. But this problem isn't solved. I tried to
>>>> access some functions of packet_header_default like formatter
>>>> and base, it returned me an AtrributeError like this:
>>>> 
>>>> AttributeError: 'packet_header2_sptr' object has no attribute
>>>> 'formatter', which means the packet_header2 wasn't really a
>>>> derived class of packet_header_default.
>>>> 
>>>> I confirmed my conjecture by checking the 
>>>> /usr/local/lib/python2.7/dist-packages/my_oot/my_oot_swig.py
>>>> where the classes are stored in python.  I found that the class
>>>> packet_header2 is defined as *class packet_header2(object)*. So
>>>> the packet_header2 *isn't* installed as a derived class of
>>>> *gr::digital::packet_header_default*.  what I expected was
>>>> *packet_header2(gr::digital::packet_header_default)*.
>>>> 
>>>> So I'm asking you that how to correctly derive my class (eg: 
>>>> packet_header2) in my own oot module based on a class (eg: 
>>>> packet_header_default) in an existing module (eg: gr-digital)?
>>>> 
>>>> My packet_header2.h and packet_header2.cc are attached for your
>>>> reference.
>>>> 
>>>> Thanks! Best, Zhe
>>>> 
>>>> 
>>>> 
> 

--
Dipl.-Inform. Bastian Bloessl
Distributed Embedded Systems Group
University of Paderborn, Germany
http://www.ccs-labs.org/~bloessl/