'goto" gone from computer languages or is it!

[vrs]

From: "Dave Dunfield" <dave04a at dunfield.com>
> So, although unlikely that the compiler would defer two operations and not
> another, it is potentially possible that the "results" could also be 0 0
1,
> 0 0 2, 0 1 1 etc. (in any order).

Agreed.

> Officially this type of code (that which modifies an Lvalue multiple times
> within the same sequence interval) invokes "undefined behaviour", which
> means that the compiler can do "anything" - although highly unlikely, the
> compiler can happily return 6 6 6 in this case, and leave the value of i
at
> 31415 (or anything else) ... and be performing in a perfectly legal sense
> - undefined operation is exactly that. The function performed is not
defined
> by the standard.

I think the functions to be performed are defined, and only their order is
undefined.

> On other words, it's not valid 'C' (although it is syntactically correct,
and
> most compilers will accept it without a diagnostic).

Which would make this an overstatement.  I think it is perfectly valid C,
and the compiler has (after much deliberation) been allowed to generate the
most efficient code.

> I think the OP's point has been completely missed (that a valid program is
a
> inherently very definitive and detailed specification).

I thought the point was that, at the margins, the "valid program" is *not*
as detailed a specification as was claimed/expected.  (Though I still don't
know of anything more detailed.  In fact, I think most programs are
over-specifications of the desired behavior.  That is, they require a lot of
specific behavior that is actually unimportant to the correct result.)

    Vince