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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