J3/15-148
To:        J3
From:      Van Snyder
Subject:   Interpretation concerning vector subscripts and arguments
Date: 2015 February 24

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NUMBER: F08/0135
TITLE: Vector subscripted actual makes VALUE dummy undefinable?
KEYWORDS: VALUE, definable, vector subscript
DEFECT TYPE: Interpretation
STATUS: J3 consideration in progress

QUESTION:

12.5.2.4p18 [295:3-4] says
  "If the actual argument is an array section having a vector
   subscript, the dummy argument is not definable and shall not have
   the ASYNCHRONOUS, INTENT (OUT), INTENT (INOUT), or VOLATILE
   attributes."

This would seem to be a strange requirement when the dummy argument
has the VALUE attribute (and so is not argument-associated with the
actual argument anyway).

Consider

  program P1
    real :: X(3)
    call S1 ( X ( [ 1, 3, 2 ] ) )
  contains
    subroutine S1 ( A )
      real, value :: A(:)
      A = 3
      print *, A
    end subroutine
  end program

and

  PROGRAM p2
    REAL :: x(3) = [ 10,20,30 ]
    OPEN(10,ASYNCHRONOUS='YES',FORM='UNFORMATTED')
    CALL s2( x( [ 1,2,2,1 ] ) )
  CONTAINS
    SUBROUTINE s2(a2)
      REAL,VALUE,ASYNCHRONOUS :: a2(:)
      READ(10,ASYNCHRONOUS='YES') a2
      PRINT *,'reading...'
      WAIT(10)
      PRINT *,a2
    END SUBROUTINE
  END PROGRAM

Are these two programs standard-conforming?  In particular, is the
assignment to A permitted in S1, and is the dummy argument a2
permitted to have the ASYNCHRONOUS attribute in s2.

ANSWER:

These two programs were intended to be standard-conforming.  Subclause
12.5.2.3 states that a VALUE dummy argument is associated with a
definable data object and not with the actual argument.  An edit is
supplied to correct this mistake.

EDITS:

[295:3] 12.5.2.4 Ordinary dummy variables, p18
  After "vector subscript"
  insert "and the dummy argument does not have the VALUE attribute".

HISTORY: 15-xxx    m206  F08/0135 submitted

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