See also :envvar:`PYTHONUNBUFFERED`.
-.. XXX should the -U option be documented?
Print a message each time a module is initialized, showing the place
.. note:: The line numbers in error messages will be off by one.
Warn about Python 3.x incompatibilities which cannot be fixed trivially by
+Options you shouldn't use
+ Reserved for use by Jython_.
+.. _Jython: http://jython.org
+ Turns all string literals into unicodes globally. Do not be tempted to use
+ this option as it will probably break your world. It also produces
+ ``.pyc`` files with a different magic number than normal. Instead, you can
+ enable unicode literals on a per-module basis by using::
+ from __future__ import unicode_literals
+ at the top of the file. See :mod:`__future__` for details.
+ Reserved for alternative implementations of Python to use for their own