J3/14-209
To: J3
From: Malcolm Cohen
Subject: Interp re specifiers in image control statements
Date: 2014 June 26

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NUMBER: F08/0113
TITLE: Specifiers in image control statements
KEYWORDS: STAT=, ERRMSG=, ACQUIRED_LOCK=, image control
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress

QUESTION:

Consider

  CHARACTER(80) text(0:100),msg
  INTEGER stat,istat(2)
  REAL,ALLOCATABLE :: x(:)
  TYPE(LOCK_TYPE) :: lock[*], alock(0:80)[*]
  LOGICAL acq, aacq(0:80)
  ...
  SYNC ALL(STAT=stat,ERRMSG=text(stat))       ! A
  SYNC IMAGES (*,STAT=stat,ERRMSG=text(stat)) ! B
  SYNC MEMORY(STAT=stat,ERRMSG=text(stat))    ! C
  LOCK(lock,ACQUIRED_LOCK=acq, &
       STAT=istat(MERGE(1,2,acq)), &
       ERRMSG=text(istat(MERGE(1,2,acq))))    ! D
  UNLOCK(lock,STAT=stat,ERRMSG=text(stat))    ! E
  LOCK(alock(stat),STAT=stat)                 ! F
  msg = ''
  UNLOCK(alock(LEN_TRIM(msg)),STAT=stat, &
         ERRMSG=msg)                          ! G
  stat = 13
  SYNC IMAGES(stat,STAT=stat)                 ! H
  msg = 'oops'
  SYNC IMAGES(LEN_TRIM(msg),STAT=stat, &
              ERRMSG=msg)                     ! I

In each of the statements labelled A-F, there is a dependency between
the STAT= specifier and the ERRMSG= specifier.  There appears to be no
prohibition against this.

Additionally, in the LOCK statement (D), there is a dependency between
the ACQUIRED_LOCK= specifier and the STAT= specifier (there is no
dependency between ACQUIRED_LOCK= and ERRMSG= because the former is
only set on successful execution and the latter is only set on an
error condition).  There appears to be no restrictions at all on any
dependencies from ACQUIRED_LOCK=.

In the LOCK statement (F), there is a dependency between the STAT=
specifier and the lock variable.  Similarly for the UNLOCK (G), there
is a dependency between the lock variable and the ERRMSG= specifier.

In the SYNC IMAGES statement (H), there is a dependency between the
STAT= variable and the image set.  In the SYNC IMAGES statement (I),
there is a dependency between the ERRMSG= variable and the image set.

Are all these examples conforming, and if so, is the dependent
variable referenced with the value of the other variable at the
beginning of execution of the statement or at the end of execution of
the statement?

ANSWER:

No interpretation is established and therefore these are not
conforming.  An edit is provided to clarify this.

EDITS:

[190:16-] 8.5.4 SYNC IMAGES statement, insert new p1,
  "The value of <image-set> shall not depend on the value of
   <stat-variable> or <errmsg-variable>.".

[194:6-] 8.5.6 LOCK and UNLOCK statements, insert new p1,
  "The <lock-variable> shall not depend on the value of
   <stat-variable>, <errmsg-variable>, or the
   <scalar-logical-variable> in the ACQUIRED_LOCK= specifier.
   The <scalar-logical-variable> shall not depend on the
   <lock-variable>, <stat-variable>, or <errmsg-variable>.".

[195:2-] 8.5.7 STAT= and ERRMSG= specifiers..., insert new p1,
  "The <stat-variable> shall not depend on the value of the
   <errmsg-variable>, <lock-variable>, or the
   <scalar-logical-variable> in the ACQUIRED_LOCK= specifier.
   The <errmsg-variable> shall not depend on the value of the
   <stat-variable>, <lock-variable>, or the <scalar-logical-variable>
   in the ACQUIRED_LOCK= specifier.".

SUBMITTED BY: Malcolm Cohen

HISTORY: m204  14-mmm    Submitted

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