Funny issue with casting double to ulong

[H. S. Teoh via Digitalmars-d-learn]

On Mon, Jul 03, 2017 at 05:38:56AM +0000, Era Scarecrow via Digitalmars-d-learn wrote:
> On Monday, 3 July 2017 at 03:57:25 UTC, Basile B wrote:
> > 6.251 has no perfect double representation. It's real value is:
> 
>  I almost wonder if a BCD, fixed length or alternative for floating
>  point should be an option... Either library, or a hook to change how
>  the FPU works since doubles are suppose to do 16-18 digits of perfect
>  simple floatingpoint for the purposes of money and the like without
>  relying on such imperfect transitions.

>From what I've heard, word on the street is to avoid using
floating-point for money calculations, and use fixed-point arithmetic
instead (i.e., basically ints / longs, with a built-in decimal point in
a fixed position).  Inexact representations of certain fractions of tens
like the above are one reason for this.

I don't think there's a way to change how the FPU works -- the hardware
is coded that way and can't be changed.  You'd have to build your own
library or use an existing one for this purpose.


T

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