Re: Conflicts between C standard and 754-2008
Not sent to 754, because I am not on it.
On Jan 19 2011, John Pryce wrote:
I am coming late to this discussion. It seems to me that an interval
standard will provide an incentive to clear up many of the ambiguities or
incompatibilities discussed in this thread. Provided, as Dan said, we
make things as clear as possible at the logical and mathematical level.
It will take time, but I recall a phrase in a book by E.M. Beale, one of
the gurus of linear & nonlinear programming. In his experience in
industry "often the first time anyone realises a constraint exists is
when one propounds a solution that violates it". It's analogous but a bit
the other way about here: there are many "solutions" -- e.g. current
language implementations -- out there. P1788 will comprise a constraint,
and it will be clear that the solutions violate it in various ways. And
they will be changed over time to conform. I hope.
No chance. Not in my lifetime, let alone in my working lifetime. Sorry.
Here are some of the reasons:
The basic 754 model is seriously flawed, and seriously incompatible
with the arithmetic models that have been used by mainstream programming
languages for the past 55 years. That is why it has been adopted only in
part by all of the languages that I know of that have adopted it. Many
people hoped that the revision would improve that, but it didn't; 1788 has
an opportunity to do so, certainly.
On this matter, but is there a draft of 1788? All I have seen is this
thread. If I have been told before, I apologise.
c99 has been rejected by much of the IT community, its 754 features
are unusable in portable OR robust programs, and WG14 has ceased to
operate effectively as an international standards body. Any attempt to
change the language to conform with anything that would provide portability
and robustness would be blocked by the current groups dominating WG14, and
almost all other communities have given up on it.
Regards,
Nick Maclaren.