.. index:: triple: module; search; path
-Importing this module will append site-specific paths to the module search path.
+Importing this module will append site-specific paths to the module search
+path, unless :option:`-S` was used. In that case, this module can be safely
+imported with no automatic modifications to the module search path. To
+explicitly trigger the usual site-specific additions, call this module's
pair: site-python; directory
.. envvar:: PYTHONUSERBASE
+ Adds all the standard site-specific directories to the module search
+ path. This function is called automatically when this module is imported,
+ unless the python interpreter was run with the :option:`-S` flag.
.. function:: addsitedir(sitedir, known_paths=None)
Adds a directory to sys.path and processes its pth files.