What's implementation defined? (was Re: are enums integers in ANSI?)

[T. William Wells]

In article <1988Nov28.215053.3129 at utzoo.uucp> henry at utzoo.uucp (Henry Spencer) writes:
: In article <219 at twwells.uucp> bill at twwells.UUCP (T. William Wells) writes:
: >But it does!  The standard says that which one it is compatible with
: >is "implementation defined". That implies that it has to be
: >documented.
:
: Yes, but this is not entirely inconsistent with Dennis's suggestion.

Oh, I agree; I was only quibbling about the "announce in advance"
part.

: No; what we have here is a situation in which the legality of such a
: program is implementation-defined.  It is not improper to fail to translate
: an illegal program.

"Implementation defined" is kind of wierd here. Implementation
defined behavior applies to "a correct program construct...", yet we
have the logical contradiction of "implementation defined" being used
to determine what a correct program construct *is*.

Since this kind of thing occurs throughout the standard, I'm forced
to conclude that they intended that some things can be implementation
defined to be incorrect, regardless of the stated definition of
"implementation defined".

---
Bill
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