Non-ASCII characters in C

Question

I was looking at google go's runtime source code (at https://go.googlecode.com/hg/src/pkg/runtime/ ), and it seems they use a special character for their function names, · . (Look for example at https://go.googlecode.com/hg/src/pkg/runtime/cgocall.c ). Is this accepted across major compilers? It's not ANSI C, is it? Or is it just some macro magic?

Thank you!

Answer 1

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.

Answer 2

Do you mean the dot? It's character code 183 from ISO 8859-1 (ISO Latin-1) - it's an extended ASCII code corresponding (apparently) to the Georgian comma, aka "middle dot". It is actually a legal character.