[rrd-developers] Re: Representation of NAN and INF

Alex van den Bogaerdt alex at slot.hollandcasino.nl
Thu Jul 26 16:52:46 MEST 2001


Dan McGinn-Combs wrote:

> Alex - you are correct. VB fails in those instances (1/0 and 0/0). And to
> think I used to enjoy mathematics! My goal is to simplify my life on a
> Windows platform.

If everything is implemented as it should, you should provide the
functions: isnan(), finite(), isinf()

isnan() should return 1 (true) when its parameter is not a number
isinf() should return -1 when its parameter is a negative
  infinite value, +1 when its parameter is a positive infinite
  value and 0 otherwise.

finite() should return 1 when both isnan() and isinf() return 0

If these functions are already available, use them.  If they're not,
you have to create them yourself.

Next thing to do is generate apropriate values that will never occur
otherwise.

If these conditions are met, it should be rather simple to port
RRDtool (with respect to the numbers anyway).

Note that RRDtool *should* be OK but maybe you find something wrong.
When you do, please let us know.

HTH
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