Re: precise floats

["Corey Ashford" <corSPAMey@rational.com>]

Robert Dewar wrote in message ...
>C Green said
><<
>  In article <6q7vtb$jk$1@heliodor.xara.net>,
>  Bob Fletcher <bob@radge.nospam.globalnet.co.uk> wrote:
>    What is the best way to define a float type that has greater precision,
>    (like a lot greater), than the default one? Is there a simple way to do
>    this?
>
>      type my_very_precise_type is digits <N>;
>
>  where <N> is the number of digits of precision you need.  Be aware, however,
>  that few compilers support float types of precision greater than 15 digits.
>>>
>
>Surely better advice is
>
>     type my_very_precise_type is System.Max_Digits;
[snip]

I think this is bad advice.

You want to find out at compile time whether or not the compiler
supports the precision you need, not at runtime where the system may
start behaving in mysterious ways because of inadequate precision.

I suppose it's another story if you just want the maximum precision that
the hardware allows.  I think that'd be a rare case though.

- Corey