J3/00-287r2

Date:    20 Sep 2000
To:      J3
From:    Dan Nagle
Subject: Passing IO Mode to DTIO routines (Unresolved Issue #30)

The interaction of user specified DTIO routines and the modes
specified in format control and in I/O control lists is leftover
business from 153.  This paper addresses this issue.

Briefly, an intrinsic derived type is defined in the
ISO_FORTRAN_ENV module.  An argument
of this type is passed to the user specified DTIO routines.

The INTRINSIC derived type is named ISO_IO_MODE.  The
derived type specifies the current state of the following modes:
BLANK, DECIMAL, PAD, ROUND, SCALE, and SIGN.

Edits:

190:30+
                                   io_mode, &

190:31+
   USE, INTRINSIC :: ISO_FORTRAN_ENV

190: 37+
   TYPE( ISO_IO_MODE), OPTIONAL, INTENT( IN) :: io_mode

191:7+
                                   io_mode, &

191:8+
   USE, INTRINSIC :: ISO_FORTRAN_ENV

191: 14+
   TYPE( ISO_IO_MODE), OPTIONAL, INTENT( IN) :: io_mode

192:27+ add paragraph
The processor shall provide the current values of the input/output modes
in the argument io_mode (13.17.2.3).

194:7+ add to Note
INQUIRE returns the state of the input/output modes as established by the most recently
executed OPEN statement for this unit, or the default state for the modes
if no OPEN has been executed for the unit.  The current state of each
input/output mode is represented by the value of the
corresponding component of io_mode (13.17.2.3).

198:3 replace
"executed." with "executed, unless the INQUIRE statement specifies
a unit number that is the same unit specified in a currently
executing data transfer statement, in which case,
it returns values in effect prior to the initiation of that data transfer statement.

339:33 replace
"values." with "values and public named derived types defined by the standard."

340:22+
13.17.2.3 Input/output mode type
Variables of this derived type are used to pass
the current input/output mode to user-defined derived-type
input/output procedures (9.5.4.4.3).

TYPE :: ISO_IO_MODE
   INTEGER :: SCALE                                   ! scale factor
   CHARACTER( LEN= 2) :: BLANK           ! "BN" | "BZ"
   CHARACTER( LEN= 2) :: DECIMAL      ! "DC" | "DP"
   CHARACTER( LEN= 2) :: ROUND          ! "RU" | "RD" | "RZ" | "RN" | "RP" | "RC"
   CHARACTER( LEN= 2) :: SIGN               ! "SP" | "SS"
   CHARACTER( LEN= 3) :: PAD                ! "YES" | "NO"
END TYPE ISO_IO_MODE

When passed to a child data transfer procedure by the processor:
-The SCALE component indicates the
scale factor currently in effect.
-The BLANK component indicates
the blank interpretation mode currently in effect.  It has the value BN to indicate
NULL and BZ to indicate ZERO.
-The DECIMAL component indicates
the decimal mode currently in effect.  It has the value DC to indicate
COMMA and DP to indicate POINT.
-The ROUND component indicates the
rounding mode currently in effect.  It has the value RU to indicate
UP, RD to indicate DOWN, RZ to indicate ZERO, RN to indicate
NEAREST, RP to indicate PROCESSOR_DEPENDENT,
and RC to indicate COMPATIBLE.
-The SIGN component indicates
the sign mode currently in effect.  It has the value SP to indicate
printing plus signs and SS to indicate suppressing plus signs.
-The PAD component indicates
the pad mode currently in effect.  It has the value YES to indicate
padding is performed and NO to indicate padding is not performed.