[Paul Dubois]

... I have been running into a number of odd errors caused by code like the following. The behavior seems to be machine dependent.

Which version(s) of Python? (Released, current CVS, all, ...?)

fooflag = 0 try: import foo except ImportError: fooflag = 1

I have had this result in a seg fault upon exit,

Does or does not "foo" exist? Or does it segfault both ways? Either way, run Python -vv to get a trace of what it's trying during the import attempt. The last line displayed before the segfault may be a useful clue. You may even discover you're really importing a compiled foo extension module with a hardcoded segfault in module init <wink>.

and also when something like this was in file xxx.py inside a package, and the __init__.py did

from xxx import fooflag

I've had it tell me xxx had no attribute fooflag. I added "print fooflag" at the bottom of the file and it fixed it. That was on a DEC. On Linux it worked.

I suppose I should be testing for the ability to import foo some other way but I don't know what it is.

That's "the usual" way to check imports; if it were a widespread problem under any version of Python, I expect we would have heard about it before. If you have useful followups, you should record them in a bug report on SourceForge (Python-Dev is a black hole for bug reports).