(j3.2006) Question about pointer components of coindexed objects

[John Reid]

Clune, Thomas L. (GSFC-6101) wrote:
> It would be pretty useless to allow following pointers on other images
> if we cannot safely check their association.  As such, I?d be strongly
> in favor of the suggested note for C1542.    I?m more neutral on
> NULLIFY.   Modifying the state of a pointer on another image would seem
> to be a more complex thing than accessing elements of its target.

You have made me realize that in my earlier message, I discussed only 
NULLIFY.

In 16.9.1 [353:5-6], which is talking about the specifications of the 
intrinsic procedures, we have "The ?Argument(s)? paragraphs specify 
requirements on the actual arguments of the procedures." so I see no 
problem with Malcolm's note re C1542.

Clause 16 does not talk about dummy arguments of intrinsic procedures 
except in 16.9.1 [353:6], following the sentence I have just quoted: 
"The result characteristics are sometimes specified in terms of the 
characteristics of dummy arguments." I don't see this sentence as 
helpful. Could we delete it?

John.

>
>
>> On Jul 24, 2017, at 2:25 AM, Malcolm Cohen <malcolm at nag-j.co.jp
>> <mailto:malcolm at nag-j.co.jp>> wrote:
>>
>> Hi folks,
>>
>> Consider:
>>
>> Program n9a
>>   Type t
>>     Integer,Pointer :: p
>>   End Type
>>   Type(t) x[*]
>>   Nullify(x[1]%p)
>>   Print *,'ok if F?',Associated(x[1]%p)
>> End Program
>>
>> There are two questions:
>>
>> (1)  Is the NULLIFY conforming?  It certainly looks conforming to me.
>> However another compiler claims that it is not permitted.
>>
>> (2) If the ASSOCIATED conforming?  Since we?re allowed to follow
>> pointers on other images, e.g. ?x[1]%p = 3?, I don?t see why it should
>> be a problem.  However, one compiler thinks it falls foul of
>>                 C1542 The actual argument corresponding to a dummy
>> pointer shall not be a coindexed object.
>> It is not at all obvious that C1542 should apply to intrinsic
>> procedures?  A second compiler claimed that x[1]%p was not a pointer,
>> throwing further confusion onto the fire.  Anyway, I think that either
>> ASSOCIATED should say that you can?t use it on coindexed objects, or
>> C1542 should be followed by a Note saying it does not apply to the
>> ASSOCIATED intrinsic, to clarify the situation.
>>
>> Any comments about these cases would be welcome (especially from Bill!).
>>
>> Cheers,
>> --
>> ..............Malcolm Cohen, NAG Oxford/Tokyo.
>>
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