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Subject: Re: [OMPI devel] opal / fortran / Flogical
From: Ralph Castain (rhc_at_[hidden])
Date: 2009-06-03 13:30:36

I'm not entirely sure what comment is being discussed. The comment in
opal/util/arch.c (written by me long ago) should not be taken seriously - it
was nothing more than a half-hearted attempt to appease the stormy
controversy (mostly objections from George and a little from Brian) created
by my moving this code to OPAL. It had no technical validity behind it at

Somewhat amusing to see that comment now used as justification for leaving
the code there by some of the same people. ;-)

The question of whether or not we accurately deal with Fortran variable
sizes was always present, even when this code was in the OMPI layer. It is a
tad troublesome as Fortran advocates -do- occasionally set the flags that
can cause the variables to differ from their C counterparts. Rather than
some obscure comment in the source code, we should probably generate a
warning and (hopefully) abort when someone uses those flags to avoid
creating hard-to-debug errors.

On Wed, Jun 3, 2009 at 10:58 AM, Iain Bason <Iain.Bason_at_[hidden]> wrote:

> On Jun 2, 2009, at 10:24 AM, Rainer Keller wrote:
> no, that's not an issue. The comment is correct: For any Fortran
>> integer*kind
>> we need to have _some_ C-representation as well, otherwise we disregard
>> the
>> type (tm), see e.g. the old and resolved ticket #1094.
>> The representation chosen is set in opal/util/arch.c and is conclusive as
>> far
>> as I can tell...
> Doesn't that mean that the comment is misleading? I interpret it as saying
> that a Fortran "default integer" is always the same as a C "int". I believe
> that you are saying that it really means that *any* kind of Fortran integer
> must be the same as one of C's integral types, or OpenMPI won't support it
> at all. Shouldn't the comment be clearer?
> Iain
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