Portable code: identifier length

[Garry Wiegand]

I notice in Martin Minow's C-spec postings that the spec currently says
that external identifiers may - dependent on implementation - be significant 
in as few as the first 6 characters.

I have a System V - derived machine that only recognizes 16 characters. Big 
Blue only does 6, naturally. I like long and descriptive names, but I also
like to be somewhat portable. So:

Question 1: are there *other* C implementations which do less than 31? (If
	    so, what's their choice, please?)

Question 2: are there *any* pre-processor implementations which do not adhere
	    to the full 31?

thanks

garry wiegand   (garry%cadif-oak at cu-arpa.cs.cornell.edu)