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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: S'Is_nan or S'Is_inf?
Date: Thu, 15 Jul 2010 23:03:39 +0100
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Rod Chapman <roderick.chapman@googlemail.com> writes:

> On Jul 15, 10:00 pm, Warren <ve3...@gmail.com> wrote:
>> Is there any is not-a-number or is-infinity test support in
>> Ada05+ (for floats)?  Is there any being planned?  
>
> What is S'Valid supposed to return for an S which is
> a floating-point NaN???

I thought it was supposed to produce False, but all the AARM seems to
say (13.9.2) is that the value needs to be normal and have a valid
representation for 'Valid to return True. It also lists the
circumstances under which invalid data can be created: they don't look
to me as though they include

   NaN : constant Float := 0.0 / 0.0;

GNAT certainly reports 'Valid as False for +/-Inf & NaN.