J3/15-113r3
To:        J3
Subject:   UTI 005
From:      Dan Nagle & Steve Lionel & Daniel Chen & Malcolm Cohen
Date: 2015 February 26
Reference: 15-011, 15-007


1. Introduction

This paper addresses UTI 005, which complains about a statement that
an effective arguments might be an address of a C descriptor.


2. Edits to 15-007

[454:1-6] 15.3.7 Interoperability of procedures and procedure
          interfaces, p5, replace paragraph with the following
          paragraph(s).

  "When an interoperable Fortran procedure with a simply contiguous
   dummy argument is invoked from C and the actual argument is the
   address of a C descriptor for a discontiguous object, the Fortran
   processor shall handle the difference in contiguity.

   When an interoperable C procedure whose Fortran interface has a
   simply contiguous dummy argument is invoked from Fortran and the
   effective argument is discontiguous, the Fortran processor shall
   ensure that the C procedure receives a descriptor for a contiguous
   object.

   When an interoperable C procedure whose Fortran interface has a
   simply contiguous dummy argument is invoked from C, and the actual
   argument is the address of a C descriptor for a discontiguous
   object, the C code within the procedure shall be prepared to handle
   the discontiguous argument.".
{Set out the rules.  Note we don't need the Fortran calling Fortran
 case as that is already covered by clause 12 (the rules there apply
 both to interoperable and non-interoperable procedures).}

[454:6+1-7] Delete UTI 005 if this resolves the issues.

[455:1-] At the end of that subclause (immediately before 15.4 C
         descriptors) insert the following note:
"NOTE 15.22a
 The requirements on the Fortran processor when a discontiguous actual
 argument is being passed to a simply contiguous dummy argument are
 such that the C programmer has the same functionality (and safety) as
 the Fortran programmer, when either the calling or called procedure
 are Fortran procedures.  The requirements on the C procedure, in the
 case when both the called and calling procedure are C procedures,
 effectively require that the C procedure not access memory through
 the descriptor that is not described by the descriptor; otherwise the
 program will not conform to the Fortran standard.  A dummy argument
 is simply contiguous if it has the CONTIGUOUS attribute or is an
 array that is not assumed-shape, assumed-rank, or a pointer.".

===END===