What happened to module.__file__?

[MRAB]

On 12/12/2011 00:21, Steven D'Aprano wrote:
> I've just started using a Debian system, instead of the usual RedHat
> based systems I'm used to, and module.__file__ appears to have
> disappeared for some (but not all) modules.
>
> On Fedora:
>
> [steve at orac ~]$ python -E
> Python 2.6.2 (r262:71600, Aug 21 2009, 12:22:21)
> [GCC 4.4.1 20090818 (Red Hat 4.4.1-6)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import math
>>>> math.__file__
> '/usr/lib/python2.6/lib-dynload/mathmodule.so'
>
>
>
> and on Debian squeeze:
>
> steve at runes:~$ python -E
> Python 2.6.6 (r266:84292, Dec 27 2010, 00:02:40)
> [GCC 4.4.5] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import math
>>>> math.__file__
> Traceback (most recent call last):
>    File "<stdin>", line 1, in<module>
> AttributeError: 'module' object has no attribute '__file__'
>
>
> What's going on?
>
The documentation for __file__ says: """The __file__ attribute is not
present for C modules that are statically linked into the interpreter;
for extension modules loaded dynamically from a shared library, it is
the pathname of the shared library file."""

Interestingly, none of the versions on Windows that I've tried have
that attribute for the math module. Is it platform-dependent?