- for a universal character name is less than 0x20 or in the range
- 0x7F-0x9F (inclusive), or if the universal character name
- designates a character in the basic source character set, then the
- program is ill-formed.
+ for a universal character name corresponds to a surrogate code point
+ (in the range 0xD800-0xDFFF, inclusive), the program is ill-formed.
+ Additionally, if the hexadecimal value for a universal-character-name
+ outside a character or string literal corresponds to a control character
+ (in either of the ranges 0x00-0x1F or 0x7F-0x9F, both inclusive) or to a
+ character in the basic source character set, the program is ill-formed.
+
+ C99 6.4.3: A universal character name shall not specify a character
+ whose short identifier is less than 00A0 other than 0024 ($), 0040 (@),
+ or 0060 (`), nor one in the range D800 through DFFF inclusive.