[CMake] linking libraries at many levels

[John Drescher]

On Tue, Aug 25, 2009 at 9:06 AM, Pol Monsó IRI<pmonso at iri.upc.edu> wrote:
> Hello cmake users!
>
> I'm quite new to cmake as well as makefiles, and i've bumped the same
> trouble twice. I'm trying to break a source code into several libraries and
> a main program. The scenario has one main executable called calClient which
> uses functions from three libraries, let's say 1A 1B and 2C. Everybody uses
> library 2C, that is calClient, 1A and 1B. I've stored the source codes of 1A
> 1C and 2C in a subdirectory called lib/ toghether with a CMakeLists.txt :
>
>> FIND_PACKAGE(YARP REQUIRED)
>>
>> SET(PROJECT_LIBS
>>     2C.cpp
>>     2C.h
>>     1B.cpp
>>     1B.h
>>     1A.cpp
>>     1A.hpp
>> )
>>
>> add_library(callibs ${PROJECT_LIBS})
>
> In the upper directory, toghether with the source code of the main program,
> I have:
>
>> project(calibration)
>>
>> cmake_minimum_required(VERSION 2.6)
>>
>> set(CMAKE_CXX_FLAGS "-g -Wall")
>>
>> set(PROJECT_SRC
>>     calClient.cpp
>>     calClient.hpp
>>     chaser.cpp
>>     chaser.hpp
>> )
>>
>> FIND_PACKAGE(YARP REQUIRED)
>> FIND_PACKAGE(OpenCV REQUIRED)
>>
>> add_subdirectory(lib)
>>
>> INCLUDE_DIRECTORIES(${PROJECT_SOURCE_DIR}/lib)
>> link_directories(lib)
>>
>> INCLUDE_DIRECTORIES(${OPENCV_INCLUDE_DIR})
>>
>> ADD_EXECUTABLE(calClient ${PROJECT_SRC})
>> TARGET_LINK_LIBRARIES( calClient ${OPENCV_LIBRARIES} )
>> TARGET_LINK_LIBRARIES( calClient callibs )
>
> Every header includes the headers of the files which contains the functions
> that it needs. So, calClient.hpp actually includes 1A, 1B and 2C.
>
> The output of the make command is then:
>>
>> [ 60%] Built target callibs
>> Linking CXX executable calClient
>> CMakeFiles/calClient.dir/calClient.cpp.o: In function
>> `incrementalCalibrate(yarp::dev::IPositionControl*, yarp::dev::IEncoders*)':
>> /home/pmonso/YARP/Calclient/calClient.cpp:276: undefined reference to
>> `print_double_array(double const*, int)'
>> /home/pmonso/YARP/Calclient/calClient.cpp:277: undefined reference to
>> `print_double_array(double const*, int)'
>> /home/pmonso/YARP/Calclient/calClient.cpp:295: undefined reference to
>> `print_double_array(double const*, int)'
>> CMakeFiles/calClient.dir/calClient.cpp.o: In function
>> `calibrate(yarp::dev::IPositionControl*, yarp::dev::IEncoders*)':
>> /home/pmonso/YARP/Calclient/calClient.cpp:155: undefined reference to
>> `print_double_array(double const*, int)'
>> CMakeFiles/calClient.dir/calClient.cpp.o: In function
>> `randomCalibrate(yarp::dev::IPositionControl*, yarp::dev::IEncoders*)':
>> /home/pmonso/YARP/Calclient/calClient.cpp:207: undefined reference to
>> `print_double_array(double const*, int)'
>>
>> CMakeFiles/calClient.dir/calClient.cpp.o:/home/pmonso/YARP/Calclient/calClient.cpp:208:
>> more undefined references to `print_double_array(double const*, int)' follow
>> collect2: ld returned 1 exit status
>> make[2]: *** [calClient] Error 1
>> make[1]: *** [CMakeFiles/calClient.dir/all] Error 2
>> make: *** [all] Error 2
>
>
> The function print_double_array is located in the 2C source and header files
> which, as I said, is included in calClient header as well as in headers of
> 1A and 1B.
>
> Does somebody know why linking fails? What I am doing wrong? It's driving me
> nuts!
>

I do not see you linking to yarp (whatever that is).

John