This issue has been automatically converted from the original issue lists and some formatting may not have been preserved.
Authors: Randall Meyers, WG14
Date: 1992-12-10
Reference document: X3J11/91-008
Submitted against: C90
Status: Fixed
Fixed in: C90 TC1
Converted from: dr.htm, dr_027.html
May a standard conforming implementation make characters in its character set that are not in the required source character set identifier characters? Can these additional identifier characters be used in preprocessor identifier tokens as well as post-processor identifier tokens?
Subclause G.5.2 states:
Characters other than the underscore
_, letters, and digits, that are not defined in the required source character set (such as the dollar sign$, or characters in national character sets) may appear in an identifier (subclause 6.1.2).
Comment from WG14 on 1997-09-23:
May a standard conforming implementation make characters in its character set that are not in the required source character set identifier characters?
Answer: Yes.
Can these additional identifier characters be used in preprocessor identifier tokens as well as post-processor identifier tokens?
Answer: Yes, but the C Standard is currently ambiguous about the parsing of a definition such as:
#define abc$ x
This could either define abc$ as x or abc as $x. The Correction that
follows resolves the ambiguity.
Add to subclause 6.8, page 86 (Constraints):
In the definition of an object-like macro, if the first character of a replacement list is not a character required by subclause 5.2.1, then there shall be white-space separation between the identifier and the replacement list.*
[Footnote *: This allows an implementation to choose to interpret the directive:
#define THIS$AND$THAT(a, b) ((a) + (b))
as defining a function-like macro THIS$AND$THAT, rather than an object-like
macro THIS. Whichever choice it makes, it must also issue a diagnostic.]