# Specifying build dependencies of other OOT modules in my OOT module

**URL:** <https://www.ruby-forum.com/t/specifying-build-dependencies-of-other-oot-modules-in-my-oot-module/234758>\
**Category:** GNU Radio\
**Created:** [March 27, 2015, 4:06pm UTC](https://www.ruby-forum.com/t/specifying-build-dependencies-of-other-oot-modules-in-my-oot-module/234758 "2015-03-27T16:06:10Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [March 27, 2015, 4:06pm UTC](https://www.ruby-forum.com/t/specifying-build-dependencies-of-other-oot-modules-in-my-oot-module/234758/1 "2015-03-27T16:06:10Z")

</div>

I am writing my own module.  
In the module, I am using gr-dvbt ([GitHub - BogdanDIA/gr-dvbt: DVB-T implementation in gnuradio](https://github.com/BogdanDIA/gr-dvbt))  
to  
perform Reed-Solomon en/decoding.

In this situation, how to tell ‘I am using gr-dvbt’ to cmake and make?

I’ve found some clues in other OOT modules:  
set(GR\_REQUIRED\_COMPONENTS RUNTIME FILTER FFT PMT DIGITAL)  
Keywords FFT, DIGITAL seems to indicate gr-fft, gr-digital,  
respectively.

However, I have no idea where the keywords FFT and DIGITAL come from  
which  
part of gr-fft and gr-digital.  
I am suspecting that two files, include/api.h and swig/XXXX\_swig.i. (But  
I  
might be wrong.)  
XXXX is either FFT or DIGITAL

In include/api.h: #define XXXX\_API  
In XXXX\_swig.i: #define XXXX\_API

According to my guess, I put:  
set(GR\_REQUIRED\_COMPONENTS … omitted … DVBT)

But after building and installing, I got an error in the following step:

```
$ python
>>> import myOOTmodule
ImportError: /usr/local/lib/libgnuradio-myOOTmodule.so: undefined

```

symbol: \_ZN2gr4dvbt12reed\_solomonC1Eiiiiiiii

Am I guessing wrong? Or, gr-dvbt are not available to be used by other  
OOT  
modules?

Can it be solved by modifying 1) my code or 2) gr-dvbt?

Regards,  
Jeon.