[Rock-dev] modbus library

[fahrlich]

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