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Undefined reference error despite linking the library [closed]

asked 2014-10-16 17:38:14 -0500

mhariharasudan gravatar image

updated 2014-10-16 17:39:16 -0500


I am using ROS Hydro on Ubuntu 12.04. I have a package named as libbarrett_ros. The declaration of the class arm_interface is in include/barrett_arm.h and the definition is in src/barrett_arm.cpp. The executable node (src/libbarrett_ros.cpp) creates an instance of the class barrett_arm_interface in its main function.

However, catkin_make returns the following error for me,

Linking CXX executable /home/robot/catkin_ws/devel/lib/libbarrett_ros/libbarrett_ros
CMakeFiles/libbarrett_ros.dir/src/libbarrett_ros.cpp.o: In function `int wam_main<3u>(int, char**, barrett::ProductManager&, barrett::systems::Wam<3u>&)':
libbarrett_ros.cpp:(.text._Z8wam_mainILj3EEiiPPcRN7barrett14ProductManagerERNS2_7systems3WamIXT_EEE[int wam_main<3u>(int, char**, barrett::ProductManager&, barrett::systems::Wam<3u>&)]+0x14): undefined reference to `barrett_arm_interface<3u>::barrett_arm_interface()'
CMakeFiles/libbarrett_ros.dir/src/libbarrett_ros.cpp.o: In function `int wam_main<4u>(int, char**, barrett::ProductManager&, barrett::systems::Wam<4u>&)':
libbarrett_ros.cpp:(.text._Z8wam_mainILj4EEiiPPcRN7barrett14ProductManagerERNS2_7systems3WamIXT_EEE[int wam_main<4u>(int, char**, barrett::ProductManager&, barrett::systems::Wam<4u>&)]+0x14): undefined reference to `barrett_arm_interface<4u>::barrett_arm_interface()'
CMakeFiles/libbarrett_ros.dir/src/libbarrett_ros.cpp.o: In function `int wam_main<7u>(int, char**, barrett::ProductManager&, barrett::systems::Wam<7u>&)':
libbarrett_ros.cpp:(.text._Z8wam_mainILj7EEiiPPcRN7barrett14ProductManagerERNS2_7systems3WamIXT_EEE[int wam_main<7u>(int, char**, barrett::ProductManager&, barrett::systems::Wam<7u>&)]+0x14): undefined reference to `barrett_arm_interface<7u>::barrett_arm_interface()'
collect2: ld returned 1 exit status
make[2]: *** [/home/robot/catkin_ws/devel/lib/libbarrett_ros/libbarrett_ros] Error 1
make[1]: *** [libbarrett_ros/CMakeFiles/libbarrett_ros.dir/all] Error 2
make: *** [all] Error 2
Invoking "make" failed

I know that this is a problem with linking the barrett_arm with my executable node. I have added the barrett_arm.cpp and linked the target against my executable node. But that does not solve the problem either. Please let me know what I am missing here. Thanks in advance.

My CMakeLists.txt is as below

cmake_minimum_required(VERSION 2.8.3)

find_package(catkin REQUIRED COMPONENTS

find_package(Barrett REQUIRED)
find_package(Eigen REQUIRED)

  INCLUDE_DIRS include


add_library(barrett_arm src/barrett_arm.cpp)
target_link_libraries(barrett_arm ${catkin_LIBRARIES} ${BARRETT_LIBRARIES})

add_executable(${PROJECT_NAME} src/libbarrett_ros.cpp)
target_link_libraries(${PROJECT_NAME} barrett_arm ${catkin_LIBRARIES} ${BARRETT_LIBRARIES})

add_dependencies(${PROJECT_NAME} ${catkin_EXPORTED_TARGETS} wam_msgs_gencpp)
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Closed for the following reason the question is answered, right answer was accepted by mhariharasudan
close date 2014-10-17 09:18:13.459814


The barrett_arm_interface class looks like a template class, and it looks like you're failing to link against a specific instantiation of that template. Is that class part of your library or part of the barret library you're linking to?

ahendrix gravatar image ahendrix  ( 2014-10-16 17:48:38 -0500 )edit

Yes, the barrett_arm_interface class is a template class. This is part of my library. I have written my own template class that gets instantiated with the DOF value which is 3u, 4u and 7u passed from libbarrett_ros.cpp.

mhariharasudan gravatar image mhariharasudan  ( 2014-10-16 19:35:58 -0500 )edit

Initially, I had barrett_arm_interface template class defined and declared within libbarrett_ros.cpp. And in the main function I was creating an instance of it and initializing the class as now. It all worked fine. But now when I moved that class as a separate source file, I am facing this problem

mhariharasudan gravatar image mhariharasudan  ( 2014-10-16 19:38:15 -0500 )edit

Thank you so much. You saved my day, I didnt think anything beyond "catkin linking error".

mhariharasudan gravatar image mhariharasudan  ( 2014-10-17 09:17:58 -0500 )edit

1 Answer

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answered 2014-10-16 19:57:32 -0500

ahendrix gravatar image

updated 2014-10-17 11:46:02 -0500

Unless you're creating template specializations, your template class should be implemented completely in your header file. See:

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Asked: 2014-10-16 17:38:14 -0500

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Last updated: Oct 17 '14