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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: S'Is_nan or S'Is_inf?
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References: <Xns9DB6AD1651560WarrensBlatherings@81.169.183.62>
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Date: Fri, 16 Jul 2010 10:42:38 +0200
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Date: 2010-07-16T10:42:38+02:00
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On Thu, 15 Jul 2010 23:07:51 +0100, Simon Wright wrote:

> Warren <ve3wwg@gmail.com> writes:
> 
>> Is there any is not-a-number or is-infinity test support in Ada05+
>> (for floats)?  Is there any being planned?

with Ada.Text_IO;  use Ada.Text_IO;
procedure IEEE is -- Only if Float is IEEE!
   Zero : Float := 0.0;
   Inf  : Float := 1.0 / Zero;
   NaN  : Float := 0.0 / Zero;
begin
   Put_Line ("Valid    " & Boolean'Image (Inf'Valid));
   Put_Line ("In range " & Boolean'Image (Inf <= Float'Last));
   Put_Line ("Self NaN " & Boolean'Image (NaN = NaN));
end IEEE;

On an IEEE machine it could print 3x FALSE.

> With GNAT, using a subtype
> 
>    subtype Checked_Float is Float range Float'Range;
> 
> will give you a Constraint_Error for NaN or +/-Inf.

Yes, one of the reasons not to use built-in types is that the floating
point ones most likely are IEEE with all nasty consequences.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de