[Distutils] Windows Python sys.prefix
ianb at colorstudy.com
Wed Sep 19 00:51:57 CEST 2007
Mark Hammond wrote:
>> How does Python on Windows determine sys.prefix?
> By consulting the registry. The main use-case for that is when Python is
> embedded in another executable - often, but not always, via COM. When
> Python is hosted inside excel.exe, for example, its impossible to calculate
> sys.path or sys.prefix based on that executable. In that same example,
> Python's DLL will have been loaded from a directory on the global PATH,
> which generally means the \Windows\System32 directory - so that too is no
> help in calculating the path.
> [IIRC, Python actually tries to use the executable to locate its 'landmark'
> and only falls back to the registry when that fails - but that sounds
> exactly like what is happening in your example. The gory details are in
I can certainly create a landmark if at all reasonable. I'm looking at
getpathp.c, and it looks like it just looks for lib/os.py ... and I
think it walks up from the current directory until it finds it? So
right now I have:
But perhaps if I just change it to:
it will work? On windows, does it just leave out the "/python2.5/"
portion of the lib path?
>> Is there a way to effect that?
> Setting PYTHONHOME in the environment is the only way I'm aware of.
That's kind of what workingenv did, which I'm trying to avoid -- you
have to worry about, for instance, calling another Python subprocess if
you don't want that process to be in the same environment.
Ian Bicking : ianb at colorstudy.com : http://blog.ianbicking.org
: Write code, do good : http://topp.openplans.org/careers
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