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Re: DBL_MAX,DBL_MIN defined as?

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David Mathog <dmathog@gmail.com> writes:

> What exactly do DBL_MAX and DBL_MIN define?  It looks like it is
> probably "biggest number that can be represented at a specified
> precision" and not "biggest number that can be represented".

C99 says that DBL_MAX is the maximum representable finite
floating-point number.

C99 says that DBL_MIN is the minimum normalized positive
floating-point number.  There may be smaller positive
floating-point numbers, but they are denormals.

> However the lower limit seems to be a bit squishy. The number of
> correct digits in the mantissa shrinks as the exponent becomes more
> negative until the conversion fails outright, but that's much smaller
> than DIG_MIN.

DBL_MIN, you mean.

Yes, those are denormals.

> Are we really supposed to have to do a
>   if(dtmp < DIG_MIN){ reject_it(); }

I'm not sure how to interpret the standard's wording in this
area, but if that's what your implementation does then I'd guess
that, yes, you have to.
-- 
"Programmers have the right to be ignorant of many details of your code
 and still make reasonable changes."
--Kernighan and Plauger, _Software Tools_

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Thread

DBL_MAX,DBL_MIN defined as? David Mathog <dmathog@gmail.com> - 2011-05-12 10:42 -0700
  Re: DBL_MAX,DBL_MIN defined as? blp@cs.stanford.edu (Ben Pfaff) - 2011-05-12 10:53 -0700
    Re: DBL_MAX,DBL_MIN defined as? David Mathog <dmathog@gmail.com> - 2011-05-12 11:19 -0700
    Re: DBL_MAX,DBL_MIN defined as? Tim Prince <tprince@computer.org> - 2011-05-12 14:55 -0400

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