lfs confusion

Andrew Dalke adalke at mindspring.com
Thu Sep 23 16:14:46 EDT 2004

Peter Hansen wrote:
> Wouldn't doing type(fd.tell()) be better than coupling
> the logic to what might be a changing representation of
> the data?

I suggested using repr instead of str because that
would make the smallest impact on the OP's code.

Using type(fd.tell()) == long) or rather
isinstance(fd.tell(), long) would be better,
but I can see a few possible problems.

  - What does tell() return on a 64 bit
machine?  A Python integer or long?

  - When unification is finished, will it be
that isinstance(0, long) and/or
isinstance(2**35, int) (on a 32 bit machine)?

Since the question is "can I seek to positions
 > 2**31" it seems easier to just try to seek
to something that high up.  The OP pointed out
that /dev/null supports seeks, making it the
easiest one to test on a Unix system.

I looked in the available configuration information
(distutils.sysconfig and grepping
/usr/local/lib/python2.4/config ) but didn't
see any mention of HAVE_LARGEFILE_SUPPORT so I
don't think it's possible for the runtime Python
to figure that information expect by testing
the function calls.

				dalke at dalkescientific.com

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