Problem with frozen app: compatibility between Unixware and SCO Unix

[Mike Kent]

I need to deploy a Python app on both SCO Unixware and old SCO Unix
boxes.  We freeze the app under Unixware, and set the compatibility
flag ('elfmark -t udk') on the resulting executable.  We successfully
did this using Python 1.5.2.  Recently, we decided to upgrade the app
to use Python 2.3.2.

Unfortunately, we've just discovered a nasty surprise.  Under 2.3.2,
os.path.isdir() returns True on Unixware for an existing directory
(/tmp, for example), but returns False under SCO Unix.  Ouch.

Note that this has been verified using a test program that is frozen
under Unixware, then run on Unixware and SCO Unix.  We don't currently
have a python interpreter on the SCO Unix box.

Because of the way a frozen app is involved, I'm thinking that this is
a binary compatibility problem, and will investigate further.  We do
the same 'compile under Unixware, deploy under SCO Unix' thing for
many other apps that are written in C, without encountering this
problem.

Does anyone have any suggestions on how I can best proceed?  Have you
heard of this kind of problem before?  What additional information
would you like to read?

Thanks