🚀 go-pugleaf

Jim Adcock (jimad@microsoft.com) wrote:
: In article <5367@miramon.lulea.trab.se> jbn@lulea.trab.se (Johan Bengtsson) writes:
: |Jim Adcock (jimad@microsoft.com) wrote:
: |[ Questionable C example involving compiler-generated conversion
: |  to void* deleted ]

: On the contrary, unquestionably conforming C example involving conversions
: to char*.

I thought ANSI C specifies void* to be the generic pointer type
instead of the previous char*.  Am I (and K&R2, 2nd Ed.) mistaken?

I still would call your example a degenerate case.  I still agree with you
that it would be gross to require pointer distinctness for generic pointers.

: |The fact that applying the adress operator (&) to a reference yields
: |a pointer to the referred-to object is irrelevant, since a reference
: |is just an alias for the referred-to object.  You cannot obtain
: |a pointer to a reference (as you already know).  This should not cause
: |any trouble.

We have been talking about _pointer_ distinctness (at least I hope we have),
not the result of applying the address operator (although they coincide,
except for references and perhaps arrays).  That is how I think we had
not been clear enough.

You were applying the address operator (&) to a reference-to-X (I don't
have your example available).  The result of that is not of type
pointer-to-reference-to-X, it is simply pointer-to-X, and is a pointer to
the referred-to object, not to the reference.

If pointer-distinctness is blessed, then it should be clarified that
taking the address of a reference is not regarded as a pointer to the
reference, but a pointer to the referred-to object (to me this is
already crystal clear, as defined in the ARM).

: |Perhaps with this clarification you can finally agree with us?

: I guess I don't understand what you are asking me to agree to?

That your examples need not be relevant to the discussion, or
even more preferably:

That two non-generic pointers of the same type (possibly converted from
pointer-to-derived) to different objects or data members should be
guaranteed to compare unequal.

Please? (:-)

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| Johan Bengtsson, Telia Research AB, Aurorum 6, S-951 75 Lulea, Sweden  |
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