Character Encoding Detection

[Chris Maden]

[Chris Hubick]
> In the section on autodetection of character encodings the XML spec
> states "00 3C 00 3F: UTF-16, big-endian, no Byte Order Mark (and
> thus, strictly speaking, in error)"
> 
> 	My question is, why is this an error rather than a perfectly
> acceptable untransformed UCS-2 document?

The XML spec states, by fiat, in 4.3.3, that "Entities encoded in
UTF-16 must begin with the Byte Order Mark".  So the reason the
example is an error is because the spec says so.

UCS-2 is identical to UTF-16, and so it is subject (presumably) to the
same rule.

As a side note, I was unsure until just now whether they were
equivalent, but I finally found ISO 10646-1 clause 8:

   Plane 00 of Group 00 shall be the Basic Multilingual Plane (BMP).
   The BMP can be used as a two-octet coded character set in which
   case it shall be called UCS-2.

From:
   Linkname: ISO/IEC 10646-1 including AMD 1 thru 4
        URL: http://wwwold.dkuug.dk/JTC1/SC2/WG2/docs/N1396.doc

-Chris
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