Can #define `token-string' be empty?

[B.Altman]

> Is
> 	#define	X
> valid, i.e., can the `token-string' mentioned on page 207 of K&R be empty?

According to AT&T cpp the answer is yes.
According to the latest ANSI C draft the answer is yes also.

				Boris Altman
				ATT Bell Labs Summit NJ
				{ucbvax,ihnp4,allegra}!attunix!boris