Standardized predefined CPP symbols, down with folklore

[Andrew Klossner]

[]

	"Actually, it wouldn't matter if the implementors had had the
	sense to have cpp implcitly "#define unix unix", instead of
	"#define unix 1".  The first would still permit all "#ifdef
	unix" work, while the actual implementation caused me grief one
	day when I tried to create a function called unix()"

Nope.  "#define unix unix" followed by a use of "unix" will put the
preprocessor into a loop, scanning "unix" over and over, until the
recursion depth is hit and it punts with a fatal error message.

Here's what it does under 4.2BSD:

	% cat >unix.c
	#define unix unix
	unix() {}
	% cc unix.c
	unix.c: 1: unix redefined
	unix.c: 2: unix: macro recursion
	% 

  -- Andrew Klossner   (decvax!tektronix!orca!andrew)      [UUCP]
                       (orca!andrew.tektronix at rand-relay)  [ARPA]