To: J3                                                     J3/22-107
From: John Reid
Subject: Interp. re a coarray component of a dummy argument
Date: 2022-January-15
References: 18-007r1

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NUMBER: F18/035
TITLE: Defining or referencing a coarray component of a dummy argument
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress

QUESTION 1:

On page 311 of 18-007r1, in 15.5.2.13, we have
"While an entity is associated with a dummy argument, the following
restrictions hold.
      ...
(3) Action that affects the value of the entity or any subobject of it
    shall be taken only through the dummy argument unless
     ...
   (d) the dummy argument is a coarray and the action is a coindexed
       definition of the corresponding ultimate argument coarray by a
       different image."

Should there be a similar exception for a coarray that is an ultimate
component of a dummy argument?

QUESTION 2:

On page 312 of 18-007r1, in 15.5.2.13, we have
"While an entity is associated with a dummy argument, the following
restrictions hold.
      ...
(4) If the value of the entity or any subobject of it is affected
    through the dummy argument, then at any time during the invocation
    and execution of the procedure, either before or after the
    definition, it shall be referenced only through that dummy argument
    unless
     ...
   (d) the dummy argument is a coarray and the reference is a coindexed
       reference of its corresponding ultimate argument coarray by a
       different image.

Should there be a similar exception for a coarray that is an ultimate
component of a dummy argument?

ANSWERS:

For both questions, the answer is "yes". It was intended that a
subobject of a coarray that is an ultimate component of a dummy
argument may be referenced or defined on another image by coindexing
the corresponding coarray subobject of the actual argument.

Edits are provided.

EDITS to 18-007r1:

[xiv] Introduction, Program units and procedures, last sentence,
      Insert ", or a coarray ultimate component of a dummy argument,"
      After "argument", making that sentence read
  "A coarray dummy argument, or a coarray ultimate component of a
   dummy argument, can be referenced or defined by another image."
{Add to new feature list since Fortran 2008.}

[311:44-46] In 15.5.2.13 Restrictions on entities associated with dummy
arguments, para 1,
at the end of (3)(c) delete "or", and
at the end of (3)(d) replace "image." by
"image, or
(e) the dummy argument has a coarray ultimate component and the action
    is a coindexed definition of the corresponding coarray by a
    different image."

[312:9-11] In 15.5.2.13 Restrictions on entities associated with dummy
arguments, para 1,
at the end of (4)(c) delete "or", and
at the end of (4)(d) replace "image." by
"image, or
(e) the dummy argument has a coarray ultimate component and the
    reference is a coindexed reference of the corresponding coarray
    by a different image."

[314:1-]. At the end of 15.5.2.13 Restrictions on entities associated
with dummy arguments, NOTE 5, sentence 1, replace "exception" by
"exceptions" and "coarrays enables" by "arguments that are coarrays or
have coarray components enable" so that the sentence reads
"The exceptions to the aliasing restrictions for dummy arguments that
are coarrays or have coarray components enable cross-image access while
the procedure is executing."


SUBMITTED BY: John Reid

HISTORY: 22-xxx   m226 Submitted

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