In order to keep discussions separated (I apparently did something
stupid which mixed up 2 threads), I start a new thread here.
Summarizing: when writing my own out of tree block in C++ using FFTs
(including the ‘fft/fft.h’ header) and following the tutorial
“Out-of-tree modules”, I get an error when I want to use the block in
GNU Radio Companion:
ImportError /usr/local/libgnuradio-MY_MODULE.so: undefined symbol:
According to Tom R. the FFT-library is not included in the link
process, and he suggested the following tutorial:
I started following that tutorial, setting some environment variables
first, and I found out that I am using version 3.6.5git (on an Ettus
Research USB stick) while I suspect that the suggested tutorial only
covers versions >= 3.7.
Even when I only changed the following (as suggested by the tutorial):
set(GR_REQUIRED_COMPONENTS CORE) find_package(Gnuradio "3.6.5" REQUIRED)
I get the following error when I run “cmake …/” from the
– Build type not specified: defaulting to release.
– Boost version: 1.49.0
– Found the following Boost libraries:
CMake Error at CMakeLists.txt:92 (find_package):
By not providing “FindGnuradio.cmake” in CMAKE_MODULE_PATH this
asked CMake to find a package configuration file provided by
but CMake did not find one.
Could not find a package configuration file provided by “Gnuradio”
(requested version 3.6.5) with any of the following names:
Add the installation prefix of “Gnuradio” to CMAKE_PREFIX_PATH or set
“Gnuradio_DIR” to a directory containing one of the above files. If
“Gnuradio” provides a separate development package or SDK, be sure it
So I tried (as suggested by the error message):
1) set CMAKE_MODULE_PATH to the path where
2) add the installation prefix of “Gnuradio” to CMAKE_PREFIX_PATH
The two mentioned config .cmake files are not even present on the
environment I am working on (not found by a search at the GNU radio
installation prefix which is usr/local).
So I am pretty stuck here. My goal is to get this working in my current
environment before trying to port my blocks to the latest version > 3.7.
Any help is greatly appreciated.