Re: Meeting the Scope and Purpose of P754

[Nick Maclaren <nmm1@xxxxxxxxxxxxx>]

Vincent Lefevre <vincent@xxxxxxxxxx> wrote:
> It is reasonable to consider that Annex F takes the precedence
> (it can be seen as additional constraints, so that an undefined
> or implementation-defined behavior can become defined). This is
> more or less what the end of F.1 badly says.

It is.  It is, however, not the only possible (and not even the only
possible reasonable) interpretation.  I can assure you that SC22WG14
has claimed that it is obvious that such interpretations are the only
reasonable ones at the same time that a Tier 1 vendor's representative
on SC22WG14 was telling me that another interpretation was what was
meant.

> C99 says "semantic type". See also 6.3.1.8#2 and its note about cast
> and assignment operators.

And where does it define semantic type?  Remember that the C90 (and,
much more so, C99) introduced the concept of two types that are
syntactically different but semantically identical.  It is perfectly
reasonable to say that the semantic type has nothing to do with the
actual values of a datum.

Also, according to ISO rules, 6.3.1.8#2 is normative, but its footnote
is merely informative.  6.3.1.8#2 does not mention any exceptions,
and therefore a conforming implementation is permitted to do what it
says, ignoring the footnote.  Yes, I know that SC22WG14 improperly
has cases where informative text overrides normative, but the rules
say that implementors need not take any notice of that.


Regards,
Nick Maclaren,
University of Cambridge Computing Service,
New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
Email:  nmm1@xxxxxxxxx
Tel.:  +44 1223 334761    Fax:  +44 1223 334679