(j3.2006) deallocating pointer function results

Van Snyder Van.Snyder
Mon Nov 9 15:18:22 EST 2015

On Mon, 2015-11-09 at 19:47 +0000, Bill Long wrote:
> On Nov 9, 2015, at 1:11 AM, Cohen Malcolm <malcolm at nag-j.co.jp> wrote:
> > No it does not make sense.  The dummy argument (which *is* a name, thus 
> > "name association") is associated with the effective argument, which is a 
> > pointer, being the result of a function reference.
> > 
> > Thus "changes accordingly" would mean the result of the function reference 
> > changes accordingly!  Obviously nonsense, just the same as the nonpointer 
> > case of assigning a value to a dummy associated with an actual argument of 
> > "X+1?.
> So, the effective argument is a pointer.  You seem to be saying that
> pointer cannot become disassociated.  That seems like obvious nonsense
> to me. Pointers with the INTENT(IN) attribute have that restriction,
> but that is not the case here.   Sure, when the procedure completes,
> that pointer will disappear, but that is not relevant.   The effect of
> deallocating the dummy argument is to deallocate the target of the
> pointer that is the effective argument, and to mark both the dummy
> pointer and the effective argument pointer to disassociated.  Simple.
> I don?t see how that has anything to do with the ?X+1? non-anology.

No matter what we think we believe the standard says, I'm coming around
to agree with this desire.  Otherwise, using the result of a function
that returns a pointer result would result in a leak if that pointer was
allocated by the function and there is not another pointer associated
with the same target.

> I?m coming around to believe that the point of the inconsistency in
> the original program example was that the statement
>    deallocate (pointer_valued_func_ref( ) )
> should be allowed, and the current text in the standard is too restrictive.
> Cheers,
> Bill
> Bill Long                                                                       longb at cray.com
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