(j3.2006) Interop observation

Van Snyder Van.Snyder
Mon Feb 6 18:33:05 EST 2012

As was observed in an earlier discussion on this topic, we don't want to
add anything normative, or at least not imperatively normative, that
might result in essentially all vendors needing to revise their
processors just to try to outwit people who are trying to break the

One possibility (if anything is done at all) is simply to advise that a
binding name for a Fortran procedure ought to be in mixed case, in the
hope that most processors will produce their linker names in a single
case.  I've seen all upper case, all lower case, with and without
various numbers of underscores, both before and after the Fortran name,
but never a mixed-case linker name.

Less desirable, but perhaps more helpful, would be to augment that note
with a recommendation (not a requirement) that processors do not use
mixed case in their linker names for non-BIND procedures or common

On Mon, 2012-02-06 at 15:15 -0800, Keith Bierman wrote:
> Obviously highly platform dependent. But unix flavored environments
> are common enough that a note wouldn't be unreasonable (IMNSO )
> Sent from my iPad
> On Feb 6, 2012, at 4:07 PM, Van Snyder <Van.Snyder at jpl.nasa.gov> wrote:
> > A colleague has observed that it's not terribly difficult to construct a
> > duplicate definition using interop features.
> > 
> > The example was
> > 
> >    SUBROUTINE AnyNamesubf(i)BIND(C,NAME="csubf_")
> >    USE, INTRINSIC :: iso_c_binding, ONLY: c_int
> > 
> >      INTEGER(c_int) :: i
> >      CALL Csubf(i)
> >    END SUBROUTINE AnyNamesubf
> > 
> > where Csubf was a non-interoperable Fortran external subroutine.
> > 
> > I don't think this is a normative issue for the standard, but should we
> > put a note somewhere that might help people not create these?  Maybe
> > something like advising not to give binding names to Fortran procedures
> > that are all lower case (or all upper case) and are sufficiently similar
> > to the external names of non-interoperable Fortran external procedures
> > that the linker might be sent the same name for both of them.
> > 
> > 
> > _______________________________________________
> > J3 mailing list
> > J3 at j3-fortran.org
> > http://j3-fortran.org/mailman/listinfo/j3IMNS

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