J3/14-141
To:        J3
Subject:   FAILED_IMAGES intrinsic in TS 18508
From:      Van Snyder
Date: 2014 April 16
Reference: 14-130

1. Introduction
===============

The FAILED_IMAGES intrinsic function in subclause 7.4.12 of TS 18508
reports an array of failed image indices.  If one wants to inquire
whether a particular image has failed, one would need to use

  if ( any ( the_interesting_image == failed_images() ) ) ....

It would be convenient if one could also test whether one particular
image (or set of images) had failed (or stopped).

2. Proposal
===========

An intrinsic function that reports the status of one image or several
images would be more useful.

Instead of FAILED_IMAGES, provide a function IMAGE_STATUS that returns
an array of STAT_FAILED_IMAGE, STAT_STOPPED_IMAGE, some other
processor-dependent value, or zero, for a specified set of images, or an
array of positive stopped image numbers and negative failed image
numbers (almost like FAILED_IMAGES is presently specified to do) if no
image set is specified.

3. Edits to 14-130
==================

[24:3-19 7.4.12] Delete the subclause

[25:20+] Insert a subclause

7.4.13a IMAGE_STATUS ( IMAGES, [TEAM], [KIND] ) or
        IMAGE_STATUS ( [TEAM], [KIND] )

Description: Status of images.

Class: Transformational function.

Arguments.

IMAGES  shall be a scalar or array of type integer.

TEAM ... {same as [24:7-8]}

KIND ... {same as [24:9-11]}

Result Characteristics.  Integer.  If KIND is present, the kind type
parameter is that specified by the value of KIND; otherwise, the kind
type parameter is KIND(0).

Case (i) IMAGES appears
  The result has the same rank and shape as IMAGES.

Case (ii) IMAGES does not appear
  The result is a rank one array whose extent is equal to the number of
  images that have stopped, failed, or are reporting a system-dependent
  status.

Result Value.  If TEAM is present, its value specifies the team;
otherwise the team specified is the current team.

Case (i) IMAGES appears
  If IMAGES is a scalar, the result value is STAT_FAILED_IMAGE if the
  specified image has failed, STAT_STOPPED_IMAGE if that image has
  stopped, a nonzero processor-dependent value different from
  STAT_FAILED_IMAGE or STAT_STOPPED_IMAGE if some other error has
  occurred for that image, and zero otherwise.  If IMAGES is an array,
  each element of the result is as if IMAGE_STATUS had been invoked
  for the corresponding element of IMAGES.

Case (ii) IMAGES does not appear
  The value of each element is a positive image number if an image has
  stopped, or a negative image number if an image has failed.

{Alternatively, describe IMAGE_STATUS ( IMAGES, [TEAM], [KIND] ) as an
elemental function, IMAGES "shall be of type integer", don't describe
the array case for IMAGES, and retain the scalar requirement for TEAM
and KIND.  Describe IMAGE_STATUS ( [TEAM], [KIND] ) as a
transformational function.}

Examples.  If image 3 is the only failed image in the current team and
no image of the current team has stopped, IMAGE_STATUS () has the value
-3.  If there are no stopped or failed images of the current team,
IMAGE_STATUS () is a zero-size array.  If image 3 of the current team
has failed, IMAGE_STATUS ( 3 ) has the value STAT_FAILED_IMAGE.

[40:23] Replace "failed_images" with "image_status".

[43:40-46] Replace with

  status = image_status ( i )
  if ( status == STAT_FAILED_IMAGE ) then
    confirm%available(i) = .false.
    cycle image
  end if
  if ( status /= 0 ) error stop
  call event_query ( confirm%event(i), count )