[...][...]
[ ... (INT_MAX+1)*0 ]
Furthermore, the expression above is obviously an integerI'm curious about that "violation"; a violation would require
constant expression as defined by sec 6.6 para 8. Section 6.6,
para 4, reads in part, "Each constant expression shall evaluate
to a constant that is in the range of representable values for
its type." The expression, `(INT_MAX+1)*0` violates this
constraint, and so therefore a diagnostic is mandated as per
sec 5.1.1.3 para 1. That it appears in code that is not
obviously called from `main` doesn't change that.
(at least) two sorts of logical preconditions. - The first is
that all *sequentially* (literally) evaluated sub-expression
values are representable as value - INT_MAX+1 certainly can't
be represented in generated code that conforms to the abstract
*mathematical* value - but is that necessary if _the whole_
expression is (mathematically) just 0 (because of the final
factor). And the second (related) is whether the order of the
sub-expression evaluation is relevant; if we'd assume the
expression evaluation to be considered from right to left then
it would be irrelevant what's inside the parenthesis.
From the standard quotes I cannot really recognize that these
preconditions, how to determine UB/errors/violations, would be
necessary.
I'm no native speaker and I fear my question as formulated was
hard to understand. It's basically the question of the standard
implying (INT_MAX+1)*0 to be analyzed sequentially as written
or whether it could as well analyze it from right to left and
thus recognizing no problem, since from the mathematical view -
but also practically - a concrete representable value of a here
irrelevant sub-expression isn't necessary. Or another try of a
(paraphrased) formulation; for the determination of constraint
violations does the expression have strict (sort of) sequencing
points _after each term_ (and each left-to-right sub-expression
has to be well-defined) or can it be valued/analyzed as a whole
not putting any preconditions about evaluation order etc. when
determining the overall value?
Janis
PS: One yet non-considered question that was part of my original
post was: "Is there any rationale from the _software designer_'s
perspective?"
[...]
Les messages affichés proviennent d'usenet.