Re: Import Error "undefined symbol"

[Philipp Niedermayer]

It might be as simple as adding "gnuradio::gnuradio-digital" to the "target_link_libraries" in your mymodule/lib/CMakeList.txt.

Maybe you also have to adjust the "find_package" in your mymodule/CMakeList.txt to something like "find_package(Gnuradio "3.10" REQUIRED COMPONENTS digital)".

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From: Brandon Smith [mailto:blsmit5728@gmail.com]

Sent: Monday, March 20, 2023 at 11:37 UTC+1

Subject: Import Error "undefined symbol"

You may have not linked a library in your cmake. Looks like you wanted digital packet header but have not provided a library for it. Perform ldd on /usr/local/lib/x86_64-linux-gnu/libgnuradio-mymodule.so.1.0.0 and see if the missing library is shown. 

On Mon, Mar 20, 2023 at 4:59 AM Beckmann, Niklas <niklas.beckmann1@rwth-aachen.de> wrote:

Hi everybody, 

in a Flowchart, I am using an Import Block.

Gnuradio shows me the following:

Param - Import(imports):

Import "import mymodule" failed.

The module "mymodule" is installed properly and without any error. The blocks of this module are working (except of the one that i need the import for) and showed on the sidebar where all the blocks are found. 

To get more information about the error, I opened a pyhton termial with the following result:

niklas@niklas:~$ python

Python 3.8.10 (default, Nov 14 2022, 12:59:47) 

[GCC 9.4.0] on linux

Type "help", "copyright", "credits" or "license" for more information.

>>> import mymodule

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/usr/local/lib/python3.8/dist-packages/gnuradio/mymodule/__init__.py", line 18, in <module>

    from .mymodule_python import *

ImportError: /usr/local/lib/x86_64-linux-gnu/libgnuradio-mymodule.so.1.0.0: undefined symbol: _ZTIN2gr7digital21packet_header_defaultE

I wasnt able to solve this problem now for a few days already, and therefore, I was wondering, if anyone has an idea, how to solve that, since also google did not really help. If I need to provide any further information, I will of course do so (I just did not know, what else could be important for this). 

Thank you very much for your help. 😊

Kind regards,

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