Link FFTW3 in OOT module

GNU Radio
1

Dear all

I try to link the FFTW3 lib to my OOT module but always get the error:

Linking CXX executable test-mymodule
libgnuradio-mymodule.so: undefined reference to fftw_plan_dft_1d' libgnuradio-mymodule.so: undefined reference tofftw_destroy_plan’
libgnuradio-mymodule.so: undefined reference to `fftw_malloc’

How can I add FFTW3 to cmake? I found a solution of older days where
./configure was used, but with the cmake version I can’t find a
solution. Is it possible to use gr_modtool do link a library?

Thanks for the help.
Best Regards
Mischa

2

Hi Mischa,

we need to make an FAQ of this :slight_smile:
actually, to use the fftw, you need to directly link to the fftw.
Depending on whether you need the single precision floating point
version (“fftwf_" which GNU Radio uses) or the double precision one
("fftw_”), you can use the FindFFTW3(f).cmake script from the GNU Radio
source tree,
or use my modified version.
Put the .cmake modules under cmake/Modules, and add the
find_package(FFTW3(f)) directive to your master CMakeLists.txt; also,
add the link and include directories (look at the occurences of “FFT” in
my CMakeLists.txt):

Greetings,
Marcus