[Rock-dev] modbus library

[Sylvain Joyeux]

(Cross-posting the answer to rock-users, in the future please ask
these kind of questions there)

The undefined symbols happen because you did not link to the library.
Instead of calling rock_find_cmake and include_directories
explicitely, simply add

  DEPS_CMAKE modbus

to the rock_library call.

Moreover, unless the orogen component and/or the other packages are
actually using the linux-modbus library directly, the pkg-config file
should contain the information needed for them. If you've been using
the Rock library templates, the generated pkg-config file should
already be fine.

In other words:
   drivers/base_modbus: use custom cmake Find script and DEPS_CMAKE
   drivers/irdh_bender: just use DEPS_PKGCONFIG base_modbus
   drivers/orogen/irdh_bender: add "using_library 'irdh_bender'" in
the orogen file

Sylvain

On Mon, Apr 27, 2015 at 11:17 AM, fahrlich <fahrlich at marum.de> wrote:
> Hi
>
> i wrote  a modbus driver  that depends on linux-modbus library .
>
> The driver is called base_modbus  and  i added  a FindModbus.cmake file
> to the project
> and  following lines to the  CMakeList.txt in the src folder:
>
>     set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
> "${CMAKE_SOURCE_DIR}/cmake/Modules/")
>     rock_find_cmake(modbus)
>     include_directories(${modbus})
>
> So far , this works fine .
>
> Then i wrote another driver, called irdh_bender, that inherits from
> base_modbus.
> I did the same stuff  as described above: put the findModbus.cmake
> script into the the project folder and
> adapted the CMakeLists.txt
>
> This works fine, too
>
> Then i wrote a task, to run the irdh_bender lib. Again, i put the
> findmodbus.cmake file into project folder.
> Into CmakeLists.txt i added:
>
>
>     list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}")
>     message(STATUS "  cmake module path : ${CMAKE_MODULE_PATH}")
>
>     FIND_PACKAGE(Modbus REQUIRED)
>     list(APPEND EXTRA_LIBS modbus)
>
>     include_directories(${MODBUS_INCLUDE_DIR})
>     message(STATUS "cmake module path : ${MODBUS_INCLUDE_DIR}")
>
>
>
> But if i run amake  i get following linking  error
>
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_new_tcp_pi'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_read_input_registers'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_flush'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_close'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_set_debug'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_free'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_connect'
> /home/fahrlich/code/rock/install/lib/libbase_modbus.so: Nicht
> definierter Verweis auf `modbus_strerror'
>
>
>
> But in rock/install/log/drivers/orogen/irdh_bender-configure.log ui can
> see that the lib was found :
>
>
>  cmake module path :
> /home/fahrlich/code/rock/drivers/orogen/irdh_bender/.orogen/config;/home/fahrlich/code/rock/drivers/orogen/irdh_bender
> -- Found libmodbus: /usr/lib/x86_64-linux-gnu/libmodbus.so
> -- Found modbus include Dir: /usr/include/modbus
>
>
> How can i fix this ?
>
> thanks
> Frauke
> _______________________________________________
> Rock-dev mailing list
> Rock-dev at dfki.de
> http://www.dfki.de/mailman/cgi-bin/listinfo/rock-dev