%u Wrote: > I agree with a), but not b), Can't find anything in unicode standard says > you can use the low surrogate like that
According to: http://www.cl.cam.ac.uk/~mgk25/ According to ISO 10646-1:2000, sections D.7 and 2.3c, a device receiving UTF-8 shall interpret a "malformed sequence in the same way that it interprets a character that is outside the adopted subset" and "characters that are not within the adopted subset shall be indicated to the user" by a receiving device. A quite commonly used approach in UTF-8 decoders is to replace any malformed UTF-8 sequence by a replacement character (U+FFFD), which looks a bit like an inverted question mark, or a similar symbol. Refer to this file for the above quote: http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt