2 different versions of python compiling files.

TkNeo tarun.kap at gmail.com
Thu May 22 15:56:23 EDT 2008


On May 22, 2:44 pm, Hans Nowak <zephyrfalcon!NO_SP... at gmail.com>
wrote:
> TkNeo wrote:
> > I am trying to upgrade from python 2.3 to 2.4 but not all machines can
> > be upgraded. Can you guys tell me if this scenario is possible.
>
> > 1. Any machine that uses .py files that use libraries that require 2.4
> > will have 2.4 on it.
> > 2. rest of the machines will have 2.3
>
> > now there is a shared drive. lets say i write a new library called
> > testlib.py and put it on the shared drive .. when a script uses it
> > from a 2.4 based machine, it will generate a testlib.pyc and leave it
> > on the shared drive. going forward that .pyc is used until the
> > original lib is changed. now lets say a 2.3 based machine is trying to
> > use that lib. it will try to use that pyc file which was compiled by
> > py2.4. will it work or crash ?
>
> It should work, as long as the original .py file is still there.  Each Python
> version will check for a .pyc file *corresponding to that version* (e.g. Python
> 2.4 will look for a .pyc file compiled with 2.4), and create one if it doesn't
> exist, overwriting any existing .pyc file in the process.
>
> If the original .py file is *not* there, it will most likely not work.  If you
> try to import a .pyc file with the wrong version number, you get something like
> this:
>
>  >>> import foo
> Traceback (most recent call last):
>    File "<stdin>", line 1, in ?
> ImportError: Bad magic number in foo.pyc
>
> I'm not sure what would happen if multiple Pythons try to write a .pyc file at
> the same time, though...
>
> --
> Hans Nowak (zephyrfalcon at gmail dot org)http://4.flowsnake.org/

The original .py will always be there but you know what, multiple
python versions from different computers do access that one library at
the same time.

Anyone know a possible solution ?



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