catkin_simple: Implicitly linking of yaml-cpp library fails when building in install space

asked 2020-03-12 09:42:23 -0500

prex
151 ●13 ●16 ●24

I'm using the yaml-cpp system dependency in my package.xml when building with catkin_simple:

<depend>yaml-cpp</depend>

However, this doesn't work when using catkin config --install. I need to explicitly link the yaml-cpp library in my CMakeLists to make it build:

target_link_libraries(${PROJECT_NAME} yaml-cpp)

Otherwise, I'm getting undefined reference errors. Can someone explain this to me since catkin_simple implicitly links other system dependencies just fine.

answered 2020-03-12 09:57:12 -0500

gvdhoorn
86574 ●283 ●1432 ●1054 http://cor.tudelft.nl/

updated 2020-03-12 10:38:38 -0500

I recently ran into this while fixing some catkin_lint problems.

See fkie/catkin_lint#78.

In short: yaml-cpp does not play nice with CMake's conventions. The name of the find-script uses yaml-cpp as the name, but the variables defined by it use YAML_CPP as the prefix.

catkin_simple (and actually regular Catkin as well, so I'm not sure this is a problem of catkin_simple per se), rightly assume if a find-script is called FindSomething.cmake, all variables defined by/in it are prefixed by Something (note capitalisation).

yaml-cpp does not follow this convention and this causes your linking problems (ie: CMake/Catkin generates code to link against yaml-cpp_LIBRARIES, but the variable is actually called YAML_CPP_LIBRARIES).