Re: What happened to module.file?

From	Robert Kern <robert.kern@gmail.com>
Subject	Re: What happened to module.__file__?
Date	2011-12-12 16:38 +0000
References	<4ee54918$0$11091$c3e8da3@news.astraweb.com> <4EE557F6.5040900@mrabarnett.plus.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.3558.1323707893.27778.python-list@python.org> (permalink)

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On 12/12/11 1:25 AM, MRAB wrote:
> 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@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@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?

It is build-dependent. Windows builds typically have math and several other 
stdlib "extension" modules built into the PythonXY.dll . Unix builds typically, 
but apparently not always, leave mathmodule.so and others as separate extension 
modules.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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What happened to module.__file__? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-12 00:21 +0000
  Re: What happened to module.__file__? MRAB <python@mrabarnett.plus.com> - 2011-12-12 01:25 +0000
  Re: What happened to module.__file__? Robert Kern <robert.kern@gmail.com> - 2011-12-12 16:38 +0000

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