D.1.4 Universal Character Names (UCN)

6.4.3 Universal character names

UCN allows the use of any character in a C source, not just English characters. A UCN has the format:

• \u 4_hex_digits_value

• \U 8_hex_digits_value

A UCN must not specify a value less than 00A0 other than 0024 ($), 0040 (@), or 0060 (?), nor a value in the range D800 through DFFF inclusive.

UCN may be used in identifiers, character constants, and string literals to designate characters that are not in the C basic character set.

The UCN \unnnnnnnn designates the character whose eight-digit short identifier (as specified by ISO/IEC 10646) is nnnnnnnn. Similarly, the universal character name ¯nnnn designates the character whose four-digit short identifier is nnnn (and whose eight-digit short identifier is 0000nnnn).