CGAL::CGAL on CMakiLists.txt

Question

I am a user at a CentOS 6 server, and the admin was kind enough to install CGAL on it. First I will describe the CMakeLists.txt on my local machine, for which everything works, and then my question would be why the same does not work on the server. On my laptop, I have a project that uses the EMST example https://doc.cgal.org/latest/BGL/BGL_triangulation_2_2emst_8cpp-example.html. The "outermost" CMakeLists.txt has find_package(CGAL) and the specific CMakeLists.txt has this:

add_executable(emst emst.cpp)
target_compile_options(emst BEFORE PUBLIC -mcmodel=large PRIVATE -pg -g -O2)
target_link_libraries(emst CGAL::CGAL)

The entire thing "works on my machine"(c). Usually, in the build directory of the project, I would issue cmake ../ and then in the emst-specific subdirectory make emst (of course, all this is done by an appropriate click inside CLion). Now, this very setup does not work on the server. I get the errors such as these:

/emst.cpp:99:44: error: no matching function for call to ‘source(edge_descriptor&, Triangulation&)’
         vertex_descriptor svd = source(ed,t);
                                            ^
In file included from /usr/include/CGAL/boost/graph/graph_traits_Delaunay_triangulation_2.h:25:0,

The Admin told me this:

libraries can be found in /usr/lib64 and the header files in /usr/include/CGAL.

At some point, during the cmake ../-phase on the server, I get a message such as this:

CMake Warning (dev) at utils/CMakeLists.txt:31 (add_executable):
Policy CMP0028 is not set: Double colon in target name means ALIAS or IMPORTED target. Run "cmake --help-policy CMP0028" for policy details. Use the cmake_policy command to set the policy and suppress this warning.

Target "emst" links to target "CGAL::CGAL" but the target was not found. Perhaps a find_package() call is missing for an IMPORTED target, or an ALIAS target is missing? This warning is for project developers. Use -Wno-dev to suppress it.

I tried find_package(CGAL REQUIRED) in order for it to throw an error, if not found. It appears that the package is found. What could go wrong here?

What is the version of CGAL on the server ? before 4.12 you need to use the use_file as described by Developer Paul. — mgimeno

Developer Paul Developer Paul · Accepted Answer · 2019-04-07T15:33:30

From my experience with CGAL, you need to include the use file: include(${CGAL_USE_FILE}) and then you can use the targets as needed. Based on the output message it seems that CGAL is not found since the target CGAL::CGAL doesn't exist.

So basically you need:


find_package(CGAL)

# .. other code

include(${CGAL_USE_FILE})

add_executable(myexe ...)

target_link_libraries(myexe 
    PUBLIC
        CGAL::CGAL
        CGAL::CGAL_Core # and so on...
)

CGAL::CGAL on CMakiLists.txt

1 Answers