# UHD: undefined symbol uhd\_time\_spec\_t

**URL:** <https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994>\
**Category:** GNU Radio\
**Created:** [May 19, 2015, 10:41am UTC](https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994 "2015-05-19T10:41:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [May 19, 2015, 10:41am UTC](https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994/1 "2015-05-19T10:41:36Z")

</div>

Hi all,

I’m having right now problems with a implementation of a time tag in a  
block that I’m writing. I’m basically writing a burst tagger with SOB,  
EOB  
and TX\_TIME tags. The first two are working, but the third (the one that  
uses a UHD function), is giving me problems.

I recognized that the part that is not properly working is when I write  
“uhd::time\_spec\_t”. I even tried to create an arbitrary variable by  
writing  
just “uhd::time\_spec\_t test;” in an arbitrary function and then ctest,  
and  
then I notice that there is problems with that, as the output says:

```
       " /$WORKING_DIR$/build/lib/libgnuradio-dyspan.so: undefined

```

symbol: \_ZN3uhd11time\_spec\_tC1Ed"

Make and make install of my block run without any issue.

I have in the headers and body the necessary includes, such as  
\<sys/time.h\>  
and \<uhd/types/time\_spec.hpp\>. I also added the UHD module in the  
CMakeList.txt file and it is found, as I can see this in the output:

– Build type not specified: defaulting to release.  
– Boost version: 1.54.0  
– Found the following Boost libraries:  
– filesystem  
– system  
– date\_time  
Checking for GNU Radio Module: RUNTIME

- INCLUDES=/usr/local/include
- 

LIBS=/usr/local/lib/libgnuradio-runtime.so;/usr/local/lib/libgnuradio-pmt.so  
GNURADIO\_RUNTIME\_FOUND = TRUE  
Checking for GNU Radio Module: UHD

- INCLUDES=/usr/local/include
- 

LIBS=/usr/local/lib/libgnuradio-uhd.so;/usr/local/lib/libgnuradio-runtime.so;/usr/local/lib/libgnuradio-pmt.so  
GNURADIO\_UHD\_FOUND = TRUE  
Checking for GNU Radio Module: PMT

- INCLUDES=/usr/local/include
- 

## LIBS=/usr/local/lib/libgnuradio-runtime.so;/usr/local/lib/libgnuradio-pmt.so GNURADIO\_PMT\_FOUND = TRUE

– Checking for module SWIG  
– Found SWIG version 2.0.11.  
– Configuring done  
– Generating done  
– Build files have been written to: /$WORKING\_DIR$/build

I sincerely don’t know what am I missing. Maybe I’m skipping some  
linking  
steps, but I don’t know right now how to trace this. Any type of help  
will  
be welcomed.

Thanks in advance for your opinions,

Nicolas

---

<div class="post-metadata">

**Author:** ![budu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/b5e925/32.png) [@budu](https://www.ruby-forum.com/u/budu)\
**Post date:** [May 19, 2015, 10:52am UTC](https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994/2 "2015-05-19T10:52:07Z")

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Hi Nicolas,

so the good news is that you’re doing things right:  
the CMake output contains this line:

> Checking for GNU Radio Module: UHD  
> which indicates that you did a  
> set(GR\_REQUIRED\_COMPONENTS RUNTIME UHD PMT)  
> (or even more), so the libraries that CMake _should_ link against are  
> being found.

You should check your gr-dyspan/lib/CMakeLists.txt; look for the lines  
starting with  
target\_link\_libraries(…  
These should also include ${GNURADIO\_ALL\_LIBRARIES}.

Best regards,  
Marcus

---

<div class="post-metadata">

**Author:** ![budu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/b5e925/32.png) [@budu](https://www.ruby-forum.com/u/budu)\
**Post date:** [May 19, 2015, 11:53am UTC](https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994/3 "2015-05-19T11:53:28Z")

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Hi Marcus,

You were right, I did the modifications on the CMakeList.txt file on the  
working folder, but I forgot to go into the CMakeList.txt on tue lib/  
folder. Now that I went thrhough the lib/CMakeList.txt and did the  
proper  
modificacions, the tests are passed and I can continue working.

Thank you very much for your time!

Best regards,  
Nicolas

On Tue, May 19, 2015 at 10:50 AM, Marcus Müller  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)