The issue was the REAL program outputs to 3 decimal places. I.e. I was getting rounding of 1.890 instead of 1.889. As mentioned, I don't get this issue when using MinGW 4.7.2. There was obviously something going on with my 4.6 version I was using previously.

Sorry for posting unnecessarily.



On Mon, Feb 18, 2013 at 7:20 PM, Keith Marshall <keithmarshall@users.sourceforge.net> wrote:
On 18/02/13 07:48, Daniel Carrion wrote:
> Since when is 1.8895 exactly representable in double precision FP?

Nobody said that it is.  Let me ask a more pertinent question: since
when has a rounding difference of one, in a digit which lies beyond the
limit of representable floating point precision, been considered to be
a significant error?

> I'm guessing I missed some MSDN documentation that thinks so???

I'm guessing that there is no such documentation; it doesn't even seem
to be well understood that the maximum representable precision in a 64
bit floating point number, is 15 significant decimal digits.  A format
spec of "%.17f" is a programmer error.


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