Funny issue with casting double to ulong

[Era Scarecrow via Digitalmars-d-learn]

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.