Re: Generic Pointer Type

[pa.dec.com!jac.nuo.dec.com!digits.enet.dec.com!brett@decwrl.dec.com (Bev in R. Brett)]

In article <CD3DMI.JJA@crdnns.crd.ge.com>, groleau@e7sa.crd.ge.com (Wes Groleau
 x1240 C73-8) writes...
>In article <EMERY.93Sep8133649@goldfinger.mitre.org> emery@goldfinger.mitre.or
g (David Emery) writes:
>>There is no guarantee *within the language* that any unchecked
>>conversion will have any meaning.  In particular, there are systems
>>where you *cannot* convert between arbitrary access types in any
>>meaningful sense.  For instance, access to scalar may be the address
>>of the object, but access to array may be a structure holding the
>>first index, length and address of the first element.  .......
> 
>This reminds me of another mistake made by many:  doing an unchecked conversio
n
>between an access type for an object and the address of an object of the same
>type.  Even if access types are addresses (they USUALLY are...) the access to
>an array is often the address of a structure like the one David mentioned,
>while the address of the array is actually the address of the array.

The DEC Ada compilers issue warnings in such situations.

/Bevin

ps: All the rest of this message is designed to fool some stupid piece of s/w
into posting the above, even though it is mainly a quote
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