How to link C library in Cmake file?

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Ok. Means like this target_link_libraries(odom ${catkin_LIBRARIES} /usr/local/lib), Should I change include directory also? Same problem is it possible to do in launch file? What is env value? Is it same as target_link_libraries?

/usr/local/lib should be automatically added by cmake. You only have to add your special libraries, in your case ltd2xx I guess. A launch file has nothing to do with linking. The env value is documented here.

my library is ftd2xx and (-l) is option for library name. According to you it will search and path of that library automatically. is it?

target_link_libraries(odom ${catkin_LIBRARIES} ftd2xx) should work.

Yes it searches automatically.

I tried that one but it is showing error.

imu.cpp:(.text+0x5c3): undefined reference to 'FT_GetLibraryVersion'

imu.cpp:(.text+0x671): undefined reference to 'FT_Open'

imu.cpp:(.text+0x6d4): undefined reference to 'FT_SetBaudRate' How to write -rpath in CMakeLists.txt

You don't need -rpath Where did you put libftd2xx.so? Did you write target_link_libraries(odom <path to libftd2xx.so> ${catkin_LIBRARIES})

@BennyRe I tried

target_link_libraries(odom /usr/local/lib/libftd2xx.a ${catkin_LIBRARIES})
target_link_libraries(odom ${catkin_LIBRARIES} ftd2xx)

and another combination too, still it is showing error