c90 doesn't allow additional character in identifier (over those in the basic characters set), c99 do (both with the universal character syntax -- uxxxx and uxxxxxxxx -- and an implementation defined set of other characters).
6.4.2.1/1 in c99:
identifier:
identifier-nondigit
identifier identifier-nondigit
identifier digit
identifier-nondigit:
nondigit
universal-character-name
other implementation-defined characters
nondigit: one of
_ a b c d e f g h i j k l m
n o p q r s t u v w x y z
a b c d e f g h i j k l m
n o p q r s t u v w x y z
digit: one of
0 1 2 3 4 5 6 7 8 9
i don't know how well it is supported by c implementations, i know that plan9 c compiler could handle other characters before it was standardized.
c90 doesn't allow additional character in identifier (over those in the basic characters set), c99 do (both with the universal character syntax -- uxxxx and uxxxxxxxx -- and an implementation defined set of other characters).
6.4.2.1/1 in c99:
i don't know how well it is supported by c implementations, i know that plan9 c compiler could handle other characters before it was standardized.