[Python-Dev] "can't unpack IEEE 754 special value on non-IEEE platform"

[Tim Peters]

[Fredrik Lundh]
> I just ran the PIL test suite using the current Python trunk, and the
> tests for a user-contributed plugin raised an interesting exception:
>
> ValueError: can't unpack IEEE 754 special value on non-IEEE platform
>
> fixing this is easy, but the error is somewhat confusing: since when is
> a modern Intel CPU not an IEEE platform?

Which OS and compiler were in use?  A possible cause is that the
platform didn't supply #defines for SIZEOF_DOUBLE and/or SIZEOF_FLOAT
when Python was compiled.  This was, e.g., true on Windows before rev
46065.

On an Intel box, you should see this:

>>> float.__getformat__('double')
'IEEE, little-endian'

If you get 'unknown' instead, see above.