Hi ROOTers, I’m compiling a macro that uses Pythia8. It contains the line " #include “TPythia8.h” ", however this raises an issue when compiling the macro with the .L+ option: /path/to/root/build/include/TPythia8.h:69:10: fatal error: ‘Pythia8/Pythia.h’ file not found Pythia8 has been built with …

Does it help if you do gSystem->Load("libEGPythia8") before running .x pythia8.C+? That might inject the required -I.