#define CTRL(x) followup

Arthur David Olson ado at elsie.UUCP
Sun Nov 2 03:43:51 AEST 1986


Thanks to everyone who replied to my question on whether an emulation of
Reiser cpp's handling of

	#define CTRL(x) ('x' & 037)

could be done in tentative proposed draft ANSI C.
The consensus is that the closest one came come is

	#define CTRL(x) (#x[0] & 037)

with, perhaps, a "const" cast of appropriate type thrown in to allow for uses
such as

		...
		switch (input_char) {
			case CTRL(z):	stop();
		...

And an idea for consideration:  "lint" now reports on function arguments that
are not used; if it were extended to report on macro arguments that were not
used, then old, Reiser-style constructs such as

	#define CTRL(x) ('x' & 037)

would result in "lint" warnings.
--
ANSI may be a trademark of ANSI.
Lint is a trademark of Oscar Madison.
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