ISO/IEC 9,899:2011 clause 6.4.3--Universal character name

6.4.3 Universal Character Name

Grammar

1. Universal Character Name:

universal_character-name:

\u Hex-quad(four hexadecimal digits)

\u hex-quad Hex-quad

Hex-quad:

Hexadecimal-digit    Hexadecimal-digit    Hexadecimal-digit Hexadecimal-digit

Constraints

2, a universal character name should not specify a character, its short identifier is smaller than 00a0, in addition to 0024 ($), 0040 (@), 0060 ('), It should not be within the range of D800 to DFFFF (including both). [Note: Characters that are not allowed are characters in the base character set, as well as characters that are reserved for encoding locations in ISO/IEC 10646 to control characters, the delete character and the S area (reserved for use by UTF16). ］

Describe

3.

ISO/IEC 9,899:2011 clause 6.4.3--Universal character name