(j3.2006) Assignment, coarrays, and coindexed objects

[Van Snyder]

Bill Long wrote:
> On May 14, 2015, at 4:16 PM, Van Snyder <van.snyder at jpl.nasa.gov> wrote:
>
>   
>> In 7.2.1.2p1(1,3,8) a variable is not permitted to be allocatable if it 
>> is a coarray.
>>     
>
> Not so. Allocatable coarrays are common.  The point of that text is to exclude allocatable coarrays from the automatic reallocation on assignment feature.  Without that exclusion,  whole array assignments to a coarray could turn into global syncs, which would be a disaster. 
>   

Sure, allocatable coarrays are common, but I was referring to those 
specific cases in 7.2.1.2p1 where they are prohibited for exactly the 
reason you cite.  But what about assignments that reallocate allocatable 
subobjects of coarrays or coindexed objects?  Wouldn't those be global 
syncs too?  Or would only the one in 7.2.1.2p1(3) result in a global 
sync?  I don't understand why the other two don't exclude allocatable 
subobjects of coarrays or coindexed objects.

> Cheers,
> Bill
>
>
>   
>>  In In 7.2.1.2p1(3) it's also prohibited to be a coindexed 
>> object.  I presume the latter is to cover the case of an allocatable 
>> subobject of a coarray.  Why do we care about allocatable subobjects of 
>> coarrays in 7.2.1.2p1(3), but not in 7.2.1.2p1(1,8)?
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>>     
>
> Bill Long                                                                       longb at cray.com
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