[Python-Dev] The C API and wide unicode support

[M.-A. Lemburg]

Michael Hudson wrote:
>>Shouldn't only functions whose signature uses PY_UNICODE_TYPE be
>>>name-mangled?  What am I missing?
 >
>>What about the functions that use the C macros (PyUnicode_AS_UNICODE
>>etc.) directly or indirectly? Those functions will rely on the
>>internal lay-out.
> 
> 
> They're verboten in extension modules anyway, so I don't care.

They are not disallowed in extensions... don't know where you
have that idea from.

Note that the name mangling is done to prevent an extension
which uses Unicode in some way from loading if the interpreter
and extension Unicode "width" doesn't match.

If we would allow this, extensions using the macros would cause
memory corruption since they'd index differently. That's not only
a potential cause for a seg fault, it's also a security risk.

The name mangling does not provide a 100% bullet proof way
of preventing this (an extension might use Py_UNICODE and
the Unicode macros without touching any of the other C APIs),
but it goes a long way in that direction.

-- 
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
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