J3/10-247
To: J3
From: Stan Whitlock
Subject: F03/0105 SIZE= specifier and UDDTIO
Date: 2010 October 13

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NUMBER: F03/0105
TITLE: SIZE= specifier and UDDTIO
KEYWORDS: SIZE=, UDDTIO
DEFECT TYPE: Interpretation
STATUS: J3 consideration in progress

DISCUSSION:

9.5.1.14 [191:21-26] says that when SIZE= specifier is used in a
formatted input statement with explicit format specifications, the
variable specified in the SIZE= specifier is determined by the data
edit descriptors during the input statement.  These rules, however,
did not take into account the following situation where a parent READ
statement with a DT edit descriptor invokes a user-defined DTIO
formatted read subroutine that reads input data using list-directed or
namelist READ statement.

Consider the following example:

module example
    type A
        integer x(10)

        contains

        procedure :: readArray
        generic :: read(formatted) => readArray
    end type

    contains

    subroutine readArray (dtv, unit, iotype, v_list, iostat, iomsg)
        class(A), intent(inout) :: dtv
        integer, intent(in) :: unit
        character(*), intent(in) :: iotype
        integer, intent(in) :: v_list(:)
        integer, intent(out) :: iostat
        character(*), intent(inout) :: iomsg

        read (unit, fmt=*, iostat=iostat, iomsg=iomsg) dtv%x
    end subroutine
end module

program test
use example
    type(A) :: v
    integer countChar

    open (1, file='example.input', form='formatted')

    read (1, fmt='(DT)', advance='no', size=countChar) v
end program test


Note that there is no data edit descriptor in the UDDTIO subroutine,
readArray, to count the total number of characters transferred during
the child read.


QUESTION:

Is this example intended to be standard conforming?

ANSWER:

Yes, the example is standard-conforming.  The definition of SIZE= in
[10-007 216:31] section 9.6.2.15 does not restrict SIZE= if a child
I/O is present.  The description of how SIZE= works in [219:25]
section 9.6.4.1p22 item (9) clearly indicates that SIZE= shoudl be
set even if child I/O occurs (items (5) and (6)).

EDITS:

None

SUBMITTED BY: Jim Xia

HISTORY: 07-302    m182  F03/0105 submitted
         07-302r1  m182  Passed by J3 meeting
         08-133r2  m183  Failed J3 letter ballot #15 08-101
         10-xxx    m193  Draft answer for F2008