01-172

    Interpretation 92
    Values of the PAD= Specifier in the INQUIRE Statement

To:         J3
From:       Craig Dedo
Date:       March 21, 2001
Subject:    Interpretation 000092 - Values of the PAD= Specifier in the INQUIRE
Statement

NUMBER:         000092
TITLE:          Values of the PAD= Specifier in the INQUIRE Statement
KEYWORDS:       PAD=, INQUIRE
DEFECT TYPE:    Erratum
STATUS:         J3 Consideration in Progress

QUESTION:
    The normative text of the Fortran 90 and Fortran 95 standards ([1] 9.6.1.22;
    [2] 9.6.1.22) specifies that the PAD= specifier in the INQUIRE statement
    returns the value YES if there is no connection or if the connection is for
    unformatted input/output.

    This behavior is different from the results of almost every other specifier
    for the INQUIRE statement if the property being inquired about is unknown or
    undefined.  For those specifiers, the value returned in the specifier's
    variable is either UNKNOWN or UNDEFINED.

    Is the specified behavior of the PAD= specifier for an unformatted file or
    an unconnected unit intentional?

ANSWER:
    No, this specification is in error.  Edits are supplied to correct this
    defect.

DISCUSSION:
    The concept of padding input records does not make any sense if the unit is
    connected for unformatted input/output or if the unit is not connected.  A
    return value of YES does not reflect what is really going on.  A return
    value of UNDEFINED is more appropriate in these situations.

    The normative text for this section in Fortran 95 is unchanged from Fortran
    90, so correcting this defect is an incompatibility with Fortran 90.

EDITS:
    The following edits are with respect to the Fortran 95 standard.

[3:32+]         Add the following list item to the list in section 1.5.1,
"Fortran 90 compatibility".
(3) The PAD= specifier in the INQUIRE statement in this standard returns the
value UNDEFINED instead of YES if there is no connection or the connection is
for unformatted input/output.

[159:40-41] Replace the second sentence of the paragraph in section 9.6.1.22
with the following.
The <scalar-default-char-variable> in the PAD= specifier is assigned the value
YES if the connection of the file to the unit included the PAD= specifier and
its value was YES or if there was no PAD= specifier.  If there is no connection
or if the connection is not for formatted input/output, the <scalar-default-
char-variable> is assigned the value UNDEFINED.

[325:30]    Change the entry in the table to:
+--------+-----------+------------------------+-----------+
| PAD=   | UNDEFINED | YES, NO, or UNDEFINED  | UNDEFINED |
+--------+-----------+------------------------+-----------+

SUBMITTED BY:   Craig T. Dedo
HISTORY:
    01-172      m156    Submitted with proposed response.

References
[1] ISO/IEC 1539:1991, International Standard Fortran 90
[2] ISO/IEC 1539-1:1997(E) International Standard Fortran 95, Part 1, Base
language
[3] 01-007, Fortran 2000 Draft
[4] 01-111r3, Issue 308 - Oddities for PAD= in INQUIRE
[End of J3 / 01-172]