To: J3                                                     J3/21-167
From: Malcolm Cohen
Subject: CO_BROADCAST and pointer components
Date: 2021-June-30

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NUMBER: F18/032
TITLE: CO_BROADCAST and pointer components
DEFECT TYPE: Schrodinger's Erratum
STATUS: J3 consideration in progress

QUESTION:

Consider the following program fragment:

    TYPE t
        CHARACTER(100) name
        REAL location(3)
        TYPE(t),POINTER :: antecedent
    END TYPE
    TYPE(t) x
    INTEGER src_image
    ...
    CALL co_broadcast(x,src_image)

On every image other than src_image itself, this will leave x with its
antecedent component having an undefined pointer association status.
This would seem to be not useful and likely to lead to further errors.

Was it intended to permit the A argument of CO_BROADCAST to have an
ultimate pointer component?

ANSWER:

No, this was not intended. For safety, pointer ultimate components
should be prohibited here.

An edit is provided to correct this oversight.

ALTERNATE ANSWER:

Yes, this was intended. Otherwise, individual CO_BROADCAST executions
would be required for every other component; this would be very
inconvenient.

EDIT to 18-007r1:

[355:20] 16.9.46 CO_BROADCAST, p3 Arguments, argument A,
   At the end of the second sentence add
       "or have a pointer ultimate component"
   so that the sentence becomes
       "It shall not be a coindexed object or have a pointer ultimate
        component".

ALTERNATE EDIT to 18-007r1:

None.

SUBMITTED BY: Malcolm Cohen

HISTORY: 21-167   m224  Submitted

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