[FFmpeg-devel] [PATCH] Implement the function cmdutils.c:parse_int_or_die
Wed Feb 20 08:18:44 CET 2008
On Wed, Feb 20, 2008 at 02:01:36AM -0500, D. Hugh Redelmeier wrote:
> | From: Michael Niedermayer <michaelni at gmx.at>
> | If you dont want infinty, use DBL_MAX as limit.
> | Inclusivity/exclusivity distinction doesnt make sense in a finite set. Which
> | any practical implementation uses.
> I'm not sure what you mean. Are you saying that
> x <= DBL_MAX
> is the same as
> x < DBL_MAX ?
> I don't think that that is true.
No, rather x<=DBL_MAX is the same as x<INFINITY
> | That is while in math you cant neccessarily change a
> | x<5 to a x<=C (4.999... = 5) that problem cannot occur with floats or doubles.
> I'm not sure what you mean.
He was simply saying that floating point numbers (excluding nan) are a
finite fully ordered set and thus any subset has a maximal element.
> It is likely that strtod("5") == strtod("4.9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999")
> This isn't guaranteed as far as I know.
Not sure about C99, but posix specifies that whenever the exact result
is not representable and at least DECIMAL_DIG digits are provided, the
result of strtod must be one of the two adjacent values, with the
stipulation that the sign of the error must agree with the current
> Are you saying that it isn't easy to change a < to a <=? I agree.
No, he said that it's trivial to change them with floats, just like
with integers. a<b is the same as a<=nextafter(b,-INFINITY).
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