Packing and unpacking floating point data,
i.e. Packer.pack_float, Packer.pack_double,
Unpacker.unpack_float, and Unpacker.unpack_double, are
only supported with the helper built-in _xdr module, which
relies on your operating system having the appropriate XDR library
routines.
If you have built the Python interpeter with the _xdr module,
or have built the _xdr module as a shared library,
xdrlib will use these to pack and unpack floating point
numbers. Otherwise, using these routines will raise a
ConversionError exception.
See the Python installation instructions for details on building the
_xdr module.