Load Error: Failed to load Dynamic link library

I am having a problem runnin PYTHIA8 through ROOT.
To be more precise, I am trying to run one of the example files of PYTHIA8 through root (main05.cc), in compile mode. Meaning that I ask root to just take the program as it is, build it and run it.

The problem is that I get this error:

root [1] .x main05.cc++
Info in TUnixSystem::ACLiC: creating shared library /home/user02/pythia8108/examples/./main05_cc.so
dlopen error: /home/user02/pythia8108/examples/./main05_cc.so: undefined symbol: _ZN7Pythia85Event4listEbbRSo
Load Error: Failed to load Dynamic link library /home/user02/pythia8108/examples/./main05_cc.so

I have already included in the .cc file all the header files that are in the /pythia8108/include directory. I also executed the .include command to include the pythia/include directory.

I managed to find which part of the program causes the crash by slowly commenting out one by one all the other lines in the file. It’s the pythia constructor :

Pythia pythia;

Do you have any idea what could be the problem?

see example ofuse of Pythia8 in tutorial $ROOTSYS/tutorials/pythia/pythia8.C


That won’t do.

The ROOT classes for PYTHIA8 don’t have all the methods that PYTHIA has and I can’t seem to find how to use the CellJet class of PYTHIA8 through ROOT.

That’s why I have chose the compile and run method to work with.


load libPythia8 or whatever its name is, e.g. using gSystem->Load(“libPythia8”), before compiling anything that needs it.

Cheers, Axel.

Thank you, it worked like a charm