Problem with CMake configuration for XercesC

[jhrdinka]

When I am trying to build against DD4hep included in the new lcg release: _/afs/cern.ch/sw/lcg/releases/LCG87/DD4hep/ (which is built with XercesC flag ON) I get the following error message:

-- INCLUDING DD4hepBuild.... c++11:OFF c++14:ON
CMake Error at /afs/cern.ch/sw/lcg/releases/CMake/3.5.2-a9b03/x86_64-slc6-gcc62-opt/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  Could NOT find XercesC (missing: XERCESC_LIBRARY XERCESC_INCLUDE_DIR)
Call Stack (most recent call first):
  /afs/cern.ch/sw/lcg/releases/CMake/3.5.2-a9b03/x86_64-slc6-gcc62-opt/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  /afs/cern.ch/sw/lcg/releases/LCG_87/DD4hep/00-17/x86_64-slc6-gcc62-opt/cmake/FindXercesC.cmake:60 (find_package_handle_standard_args)
  /afs/cern.ch/sw/lcg/releases/LCG_87/DD4hep/00-17/x86_64-slc6-gcc62-opt/cmake/DD4hep_XML_setup.cmake:2 (find_package)
  /afs/cern.ch/sw/lcg/releases/LCG_87/DD4hep/00-17/x86_64-slc6-gcc62-opt/cmake/DD4hep.cmake:42 (include)
  /afs/cern.ch/sw/lcg/releases/LCG_87/DD4hep/00-17/x86_64-slc6-gcc62-opt/DD4hepConfig.cmake:32 (include)
  Plugins/DD4hepPlugins/CMakeLists.txt:9 (find_package)

-- Configuring incomplete, errors occurred!

I do not want to make my project depend on XercesC. Therefore could you please change you CMake configuration?

[jlingema]

Hi Julia,

XercesC is part of the LCG stack and you can simply take it from there. The recommendation was to use XercesC rather than TinyXML for performance, if I remember correctly. All you need to change is to setup the environment variable as instructed (or use the LCG view):

export XERCESC_DIR=/afs/cern.ch/sw/lcg/releases/LCG_87/XercesC/3.1.3/x86_64-slc6-gcc62-opt/

or

export CMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH:/afs/cern.ch/sw/lcg/views/LCG_87

Cheers, Joschka

[jlingema]

This is not adding a new dependency, it just requires additional setup if you want to use the LCG build. Users of DD4hep+ACTS can still use TinyXML if they prefer (they just need to build the stack themselves).

[cgumpert]

Hi Joschka,

it is great to have the DD4HEP build available from the LCG stack, but I think that the cmake configuration of the installed DD4hep package should be self-contained, in the sense that one can simply use

find_package (DD4hep)

in ones own software package. In my opinion, no further configuration should be necessary (apart from pointing the CMAKE_PREFIX_PATH to the DD4hep installation directory). If you require the user to setup all the environment variables for all DD4hep dependencies, this is asking for incompatibilities (how would I even know against which XercesC release the build was done).

[jlingema]

Yes, I agree. From the LCG side you can get this to work by simply sourcing the setup script of the view, e.g.:

source /afs/cern.ch/sw/lcg/views/LCG_87/x86_64-slc6-gcc62-opt/setup.sh

Regarding the cmake / setup structure of DD4hep, I let the DD4hep experts respond. I was under the impression that source thisdd4hep.sh + find_package(DD4hep) is enough, but I may be wrong.

[petricm]

Hi, our DD4hep dependent software is configure with just source thisdd4hep.sh plus find_package(DD4hep REQUIRED COMPONENTS DDSegmentation DDRec DDG4)

[petricm]

So is there an issue?

[jhrdinka]

Hi, I checked now once again to be sure but I get this error although I sourced thisdd4hep.sh

[jlingema]

I'm guessing, but could it be it's because in this line it is setting XERECESCINSTALL not XERCESCINSTALL?

[petricm]

Thank you for spotting the typo, I just fixed it.

[petricm]

@jhrdinka can you please verify if this was the issue for you?

[jhrdinka]

Yesterday I was setting the path manually (export XERCESCINSTALL=/afs/cern.ch/sw/lcg/releases/XercesC/3.1.3-f6432/x86_64-slc6-gcc62-opt) but I got the same error as before. I can also install the current branch and try it

[jhrdinka]

I could now install the new branch with the configuration used for the lcg release and the Problem is solved now!