std::numeric_limits::is_iec559

[Geoff Keating]

On 04/02/2006, at 6:51 AM, Gabriel Dos Reis wrote:

> Geoffrey Keating <geoffk@geoffk.org> writes:
>
> | Gabriel Dos Reis <gdr@integrable-solutions.net> writes:
> |
> | > Roberto Bagnara <bagnara@cs.unipr.it> writes:
> | >
> | > | I have always used std::numeric_limits::is_iec559 thinking that,
> | > | as per the C++ standard, it yielded "[t]rue if and only if  
> the type
> | > | adheres to IEC 559 standard."
> | > |
> | > | On a Mac OS X 10.4 machine with GCC 4.0.1, however, I get the  
> value
> | > | true for long doubles but, as far as I can tell, the layout of
> | > | long doubles there does not conform to the 128-bit format  
> specified
> | > | by IEC 559.
> | >
> | > I don't follow.  Exactly in what aspect do you believe the Mac  
> OS X
> | > 10.4 representation is not conformant to IEC 559?
> |
> | It isn't conformant because the basic arithmetic is different.
>
> I'm intending to look further into this non-conformance issue.  I
> would appreciate if you could point me to its spec.

 From my previous message:

> see gcc/config/rs6000/darwin-ldouble-format


-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 2410 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20060204/27dc4eca/attachment.p7s>