J3/01-288

Subject: Proposed answer for Interp 9
From:    Malcolm Cohen
To:      J3
Date:    6th August 2001

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NUMBER: 000009
TITLE: INTENT of MOLD argument to TRANSFER
KEYWORDS: intrinsic function, TRANSFER, MOLD
DEFECT TYPE: Interpretation
STATUS: J3 consideration in progress

QUESTION:
In 13.3 [page 218:2], Fortran 95 states:

  The nonpointer dummy arguments of the generic intrinsic procedures in
13.14
  have INTENT(IN) if the intent is not stated explicitly.

In general, an actual argument that corresponds to a dummy argument that
does
not have the INTENT(IN) attribute does not need to be defined; you need to
look
at the particulars of the invoked procedure to decide if an actual argument
needs to be defined before the invocation.

It is likely that the only intrinsic procedure argument affected by this
change
in wording is the MOLD argument to the TRANSFER function.  The value of the
MOLD argument is never needed so there is no reason to define it before
invoking TRANSFER in a Fortran 90 program.  But, apparently it needs to be
defined in a Fortran 95 program.

This could break a program that uses a local name in a subroutine as the
MOLD
argument and doesn't always define the name with a value, or didn't save it.

In this case, MOLD is like the arguments to the numeric inquiry functions,
the
"attribute" is a compile time characteristic, not a run-time "value" and
should
have the same exception as for the inquiry functions.

(1) Was general statement about INTENT(IN) quoted above intentionally added
to
    the Fortran 95 standard (how did it get into the standard)?

(2) Is it the intent of the standard to apply this general statement to the
    MOLD argument of the TRANSFER intrinsic function?

ANSWER:
(1) Yes.

(2) Yes, but this should not imply that the MOLD argument needs to be
defined.
    An edit is supplied to clarify this situation.

EDIT:

[219:28+] Add new sentence to end of paragraph:
"If the MOLD argument to this function is a variable, it need not be
defined."

SUBMITTED BY:  Larry Rolison / Dick Hendrickson
HISTORY:  J3/97-246 m143 submitted
          WG5/N1452 Suggested revision
          J3/158-mjc-004 Revised.

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