[MPIWG Fortran] Question about an argument of MPI_Testall

Junchao Zhang jczhang at mcs.anl.gov
Wed Mar 12 10:43:14 CDT 2014


That makes sense.
I found MPI_STATUS_IGNORE and MPI_STATUSES_IGNORE are a subtle issue in
binding.
Thanks, Jeff.

--Junchao Zhang


On Wed, Mar 12, 2014 at 10:30 AM, Jeff Squyres (jsquyres) <
jsquyres at cisco.com> wrote:

> Rolf R. just reminded me off-list what the real reason is:
> MPI_STATUSES_IGNORE.
>
> We can't know what the (count) will be, but you still must be able to pass
> MPI_STATUSES_IGNORE through that dummy argument.  Hence, it must be (*),
> not (count).
>
> Keep in mind that the spec prohibits you from having a special type for
> MPI_STATUSES_IGNORE.  I.e., it must be Type(MPI_Status) so that tools can
> know how to intercept it properly.
>
> Make sense?
>
>
> On Mar 12, 2014, at 5:25 AM, N.M. Maclaren <nmm1 at cam.ac.uk> wrote:
>
> > On Mar 12 2014, Malcolm Cohen wrote:
> >>
> >> That reason is bogus, if the dummy argument is declared to have "count"
> elements the actual argument is required to have at least "count" elements,
> but this need not be exact. The Fortran standard states
> >>
> >> "The rank and shape of the actual argument need not agree with the rank
> and shape of the dummy argument, but the number of elements in the dummy
> argument shall not exceed the number of elements in the element sequence of
> the actual argument."
> >>
> >> (F2008 12.5.1.11)
> >
> > And that has been true since Fortran II - I have just checked that it
> > was explicitly stated there, too.
> >
> >
> > Regards,
> > Nick Maclaren.
> >
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>
>
> --
> Jeff Squyres
> jsquyres at cisco.com
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>
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