(j3.2006) deallocating pointer function results

[Bill Long]

On Nov 4, 2015, at 12:31 AM, Malcolm Cohen <malcolm at nag-j.co.jp> wrote:

> I agree with that.  Moreover, the DEALLOCATE sets the pointer association 
> status of the dummy argument (and thus the actual) to disassociated, which 
> clearly cannot be done unless it is a "real" pointer variable.


The fact that deallocation of a pointer causes it to become disassociated is clearly stated in 16.5.2.4(2).  While entirely expected, I don?t see a corresponding statement in that subclause that a pointer that is argument, host, or use associated with a pointer that is deallocated also becomes disassociated.  Should there be a statement like that in 16.5.2.4 (Events that cause pointers to become disassociated) ?   It then becomes relevant how the statement is worded.  If ?A pointer becomes disassociated if it is argument, use, or host associated with a pointer that becomes disassociated.?, then the case of the argument in the caller being a function reference is not a problem, since there is no ?pointer? in the caller that is argument associated.  

If the ?pointer disassociation? for the actual argument is not relevant, I don?t see any reason to disallow deallocation of the corresponding dummy pointer.  The effect is to just deallocate the target of the dummy pointer, which is the same as the target of the pointer result of the function reference in the caller.   Certainly that?s analogous to what happens if the pointer dummy is defined or becomes undefined - operations that affect only the target of the pointer. 

Allowing the deallocation of the dummy argument does not seem to be a problem in terms of implementation,  And it is more consistent with our concept of a function reference that returns a data pointer being a ?variable?. 

Cheers,
Bill

Bill Long                                                                       longb at cray.com
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