I begin to discover phpBB source code.
What I want to do :
After a successfull user login, and before session (or other internal variable) setting up the user is successfully authentified, I want to call a php script (which, based on its results, may affect theses variables saying user is or not logged).
Can you make me clear about which source code file, function, variable, may I modify? I don't know about phpbb software architecture and there are a lot of files...