On Sun, Dec 30, 2012 at 8:39 AM, nick.coghlan firstname.lastname@example.org:
[SNIP] The ``-E`` command line option allows all environment variables to be -ignored when initialising the Python interpreter. An embedding application +ignored when initializing the Python interpreter. An embedding application can enable this behaviour by setting ``Py_IgnoreEnvironmentFlag`` before calling ``Py_Initialize()``.
In the CPython source code, the ``Py_GETENV`` macro implicitly checks this flag, and always produces ``NULL`` if it is set.
+<TBD: I believe PYTHONCASEOK is checked regardless of this setting > <TBD: Does -E also ignore Windows registry keys? >
That is true and that is a bug. =)