Example on Windows Vista with ANSI=cp932:

>>> import codecs
>>> codecs.code_page_encode(1252, '\xe9')
(b'\xe9', 1)
>>> codecs.mbcs_encode('\xe9')
...
UnicodeEncodeError: 'mbcs' codec can't encode characters in position 0--1: invalid character
>>> codecs.code_page_encode(932, '\xe9')
...
UnicodeEncodeError: 'cp932' codec can't encode characters in position 0--1: invalid character
>>> codecs.code_page_encode(932, '\xe9', 'replace')
(b'e', 1)
>>> codecs.code_page_encode(932, '\xe9', 'ignore')
(b'', 8)
>>> codecs.code_page_encode(932, '\xe9', 'backslashreplace')
(b'\\xe9', 8)

You can use a code page different than the ANSI code page.

The encoding name is generated from the code page number: "cp%u" % code_page, or "mbcs" if code_page == CP_ACP.

(Oops, I forgot a printf() in mbcs2.patch)