Starting with SWI-Prolog 8.1.15, the locations for finding personal configuration files and storing extensions (packs) has changed to statisfy the free desktop standards (XDG) and reach at a common structure for all platforms.

Now, everything except for packs is installed in a directory swi-prolog below a base directory for configuration files depending on the OS. Packs are install in a directory swi-prolog below a base directory for data files. The base directories are:

• Config
  • Windows: CSIDL directory CSIDL_APPDATA (see win_folder/2)
  • Otherwise:
  • $XDG_CONFIG_HOME, defaulting to $HOME/.config
• Data
  • Windows: CSIDL directory CSIDL_LOCAL_APPDATA (see win_folder/2)
  • Otherwise:
  • $XDG_DATA_HOME, defaulting to $HOME/.local/share

In the config directory we find:

• init.pl (previously .swiplrc or swipl.ini (Windows)
  Personal initialization file
• lib (previously ~/lib/prolog)
  Personal library
• xpce (previously ~/.xpce)
  Directory holding xpce application data

In the data directory we find:

• pack (previously ~/lib/swipl/pack)
  Installed add-ons.

The system prints a warning on startup if the old init file (~/.swiplrc or `<appdata>\swipl.ini`) was found and there is no init.pl in the new location, pointing at this page.

If you use multiple versions we suggest to create the new hierarchy and make symbolic links from the old locations. Windows users should either make copies or create a file at the old location that loads the data from the new location.

See also

- https://swi-prolog.discourse.group/t/new-config-file-structure/1360/1