NaN's (was Re: FLOATING NULL?)

[Geoff Clare]

henry at zoo.toronto.edu (Henry Spencer) writes:

>  If you are willing to constrain your code to run on machines using
>IEEE floating point, you could use a NaN value... but there is no standard
>way of generating such a value or testing for it.

I agree there is no standard way of generating NaN (although sqrt(-1.0)
is your best bet).  However, there is a standard way of testing for NaN.
If x is a floating point variable, then (x != x) will be TRUE if and
only if x has the value NaN.
-- 
Geoff Clare <gwc at root.co.uk>  (Dumb American mailers: ...!uunet!root.co.uk!gwc)
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