[P1800] IEEE 754-1985 no longer a standard?

Clause of 2 of the P1800-2009 draft refers to IEEE Std 754-1985, but according to Vincent Lefèvre below, "In the case of language standards linked to the IEEE 754-1985 standard: indeed they do not magically inherit the 754-2008 standard.  Equally, any sections that previously depended on the IEEE 754-1985 standard are now 'meaningless' as there is no such standard anymore."

The P1800 should consider updating Clause 2 to refer to IEEE Std 754-2008.

-- Brad

-----Original Message-----
From: stds-754@ieee.org [mailto:stds-754@ieee.org] On Behalf Of Mike Cowlishaw
Sent: Thursday, April 09, 2009 7:17 AM
To: Vincent Lefevre
Cc: STDS-754@LISTSERV.IEEE.ORG
Subject: Re: [STDS-754] Halfway cases for binary-to-decimal conversion in IEEE 754-1985

> No, this matters, because e.g. the language standards may remain
> linked to IEEE 754-1985. For instance, this is the case of the
> ISO C99 standard (with its annex F), which has not been revised
> yet. If IEEE 754-2008 has stricter requirements than the 1985
> version, a conforming C99 implementation will not magically
> become non-conforming just because IEEE 754-2008 has obsoleted
> the 1985 version.

As I understand it: if a part of standard (A) is dependent on standard (B)
then if standard (B) is no longer a standard for any reason (due to being
revoked or superseded, for example) then that part of standard (A) is also
no longer standard.

This has always been the case, and is one reason why standards minimize
their dependence on other standards as much as makes sense.  It is also
one reason why the committee revising IEEE 754 took so long, and debated
at great length, any additions and changes.

In the case of language standards linked to the IEEE 754-1985 standard:
indeed they do not magically inherit the 754-2008 standard.  Equally, any
sections that previously depended on the IEEE 754-1985 standard are now
'meaningless' as there is no such standard anymore.  I note that the C#
and CLI standards from ECMA have already started the process of updating
their standards to refer to IEEE 754-2008, and imagine other language
standards will do the same in due course.

Hope that helps -- Mike







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