Friday question: negative zero

The IEEE floating point standard allows for negative zero, but it's hard 
to know that you have one in R.  One reliable test is to take the 
reciprocal.  For example,

 > y <- 0
 > 1/y
[1] Inf
 > y <- -y
 > 1/y
[1] -Inf

The other day I came across one in complex numbers, and it took me a 
while to figure out that negative zero was what was happening:

  > x <- complex(real = -1)
  > x
[1] -1+0i
  > 1/x
[1] -1+0i
  > x^(1/3)
[1] 0.5+0.8660254i
  > (1/x)^(1/3)
[1] 0.5-0.8660254i

(The imaginary part of 1/x is negative zero.)

As a Friday question:  are there other ways to create and detect 
negative zero in R?

And another somewhat more serious question:  is the behaviour of 
negative zero consistent across platforms?  (The calculations above were 
done in Windows in R-devel.)

Duncan Murdoch