J3/13-248
To: J3
From: Van Snyder
Subject: Interp F03/0051
Date: 2013 February 14


1. Introduction

Interp F03/0051 failed with a NO vote from Jim Xia.  It should have
failed for an entirely different reason.

The subroutine that defines formatted input excutes an INQUIRE
statement for the internal unit.  This is explicitly prohibited by
9.2.10.1p2.

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NUMBER: F03/0051
TITLE: Repeat specifiers and UDDTIO
KEYWORDS: repeat specifier, POS=, UDDTIO
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress

QUESTION:

Consider the following program:

MODULE m

  TYPE t
    INTEGER :: i
    INTEGER :: j
  END TYPE

  INTEGER :: ipos

  INTERFACE READ(FORMATTED)
    MODULE PROCEDURE formattedReadT
  END INTERFACE

CONTAINS

  SUBROUTINE formattedReadT (dtv, unit, iotype, vlist, iostat, iomsg)
    CLASS(T), INTENT(INOUT) :: dtv
    INTEGER, INTENT(IN) :: unit
    CHARACTER(*), INTENT(IN) :: iotype
    INTEGER, INTENT(IN) :: vlist(:)
    INTEGER, INTENT(OUT) :: iostat
    CHARACTER(*), INTENT(INOUT) :: iomsg

    READ(unit, *) dtv%i
    INQUIRE(unit, POS=ipos)
    READ(unit, *) dtv%j
  END SUBROUTINE

END MODULE

PROGRAM foo
  USE m
  TYPE(t) :: a
  OPEN(10, FILE='file.txt', ACCESS='stream', FORM='formatted')
  WRITE(10, '(A)') '2*3 5'
  REWIND(10)
  READ(10, *) a
  PRINT *, a%i, a%j, ipos
END PROGRAM

10.9 of Fortran 2003 states that the r*c form of list-directed input
is equivalent to r occurrences of c.  So, when the read is performed,
it is as if the input record contains two occurrences of the number 3.

The first child read statement reads the first 3, and does not advance
the file position to the next record (because it is a child data
transfer statement).  It appears that the second read statement should
read the second 3.  But the file position between the child read
statements is unclear.

What does the above program print?

ANSWER:

The standard does specify the behavior of a processor when a list
directed input record contains a r*c constant, but that is irrelevant
to the question at hand.  Executing an INQUIRE statement using an
internal unit is prohibited by 9.2.10.1p2.  The program does not
conform.

EDITS:

None.

SUBMITTED BY: Rob James

HISTORY: 05-142        m171  F03/0051 submitted
         05-142r2      m171  Passed by J3 meeting
         05-167/170    m172  Failed J3 letter ballot #11
         06-369r1      m178  Passed by J3 meeting
         07-250r1/272  m181  Failed J3 letter ballot #13
         13-nnn        m200  Revised

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