reb@nbires.UUCP (06/03/83)
In the internal documentation for Gosling's EMACS, it mentions that EMACS' use of '\' in character strings follows that of C, but then goes on to give an example for control-X as the **three** char sequence \^X ! K&R makes no mention of this notation and our C compiler (4.1BSD) does not accept it, as the two character sequence ^X is produced. Does anybody know if this is a new/future extension to C, available only in some implementations of C, an error in the EMACS documentation, an EMACS extension, or what? BTW, it seems to me that this is a much more reasonable way to represent infrequently used control characters than \nnn! Thanks, Roy Binz ucbvax!nbires!reb allegra!nbires!reb hao!nbires!reb
mark@cbosgd.UUCP (06/06/83)
The ^X notation is very useful in ASCII, but meaningless in some
other character set. C does not assume ASCII (although it does
assume a newline character, which is a pretty significant assumption).
There is an EBCDIC implementation of C. Thus, the octal escape seems
like a more appropriate mechanism, although it is a pain for us programmers.
You could always use
#define CTRL(x) ('x' & 037)
As to the EMACS documentation, why do you assume that \^X is a 3
character sequence? I would interpret that as the two character
sequence backslash control-X (since, for typographical reasons,
it's hard to print a control X character on a piece of paper).