[Mpi-forum] C++ types inaccessible after #281

[Jeff Hammond]

Why do you want to make it so damn hard for anyone to use MPI in C++ codes?
 You don't even have to do anything to support C++ because BG-MPI is based
upon MPICH2.

Can't we just for once try to take user needs into consideration instead of
trying to reduce the workload of implementers as much as possible?

Users matter.  In IBM land, they are called customers.  I assure you that
some of your largest customers care a great deal about using MPI within
C++.

You're going out of your way to try and punish your customers for using
C++.  Can't you just leave them alone?  Maybe we - the customers - need to
leave IBM alone.

Jeff

On Tue, Jun 26, 2012 at 1:43 PM, Douglas Miller <dougmill at us.ibm.com> wrote:

> I think the issue is just that how can a standard that does not specify
> how C++ fits into things (after ticket 281) then go on to define a data
> type in terms of C++ types? If there is a need for a C (not C++) complex
> datatype, that should be a new proposal. But that datatype should not, in
> my opinion, be defined in terms of something like std::complex. If a
> platform does not support something like C99 complex types, then it will
> have to implement complex types and ops itself, or be incomplete.
>
>
>
> _______________________________________________
> Douglas Miller                  BlueGene Messaging Development
> IBM Corp., Rochester, MN USA                     Bldg 030-2 A401
> dougmill at us.ibm.com               Douglas Miller/Rochester/IBM
>
> [image: Inactive hide details for Jeff Hammond ---06/26/2012 12:31:52
> PM---Jeff Hammond <jhammond at alcf.anl.gov>]Jeff Hammond ---06/26/2012
> 12:31:52 PM---Jeff Hammond <jhammond at alcf.anl.gov>
>
>
>    *Jeff Hammond <jhammond at alcf.anl.gov>*
>    Sent by: mpi-forum-bounces at lists.mpi-forum.org
>
>    06/26/2012 12:21 PM
>     Please respond to
>    Main MPI Forum mailing list <mpi-forum at lists.mpi-forum.org>
>
>
>
> To
>
>
>    Main MPI Forum mailing list <mpi-forum at lists.mpi-forum.org>,
>
>
> cc
>
>
> Subject
>
>
>    Re: [Mpi-forum] C++ types inaccessible after #281
>
>
> as far as i'm concerned, these types are only valid with the C bindings
> when a C++ compiler is used.  does that solve it?
>
> jeff
>
> On Tue, Jun 26, 2012 at 11:41 AM, Douglas Miller <*dougmill at us.ibm.com*<dougmill at us.ibm.com>>
> wrote:
>
>    I've got to raise a concern here. If we start defining MPI datatypes
>    to be C++ types then how will an implementation support that with only a C
>    compiler? I thought the point of 281 was to eradicate C++ from the standard
>    (and start over later if C++ was to be defined in the standard).
>
>
>    _______________________________________________
>    Douglas Miller                  BlueGene Messaging Development
>    IBM Corp., Rochester, MN USA                     Bldg 030-2 A401*
>    **dougmill at us.ibm.com* <dougmill at us.ibm.com>               Douglas
>    Miller/Rochester/IBM
>
>    [image: Inactive hide details for Jed Brown ---06/26/2012 11:26:16
>    AM---Jed Brown <jedbrown at mcs.anl.gov>]Jed Brown ---06/26/2012 11:26:16
>    AM---Jed Brown <*jedbrown at mcs.anl.gov* <jedbrown at mcs.anl.gov>>
>
>
>
>    *Jed Brown <**jedbrown at mcs.anl.gov* <jedbrown at mcs.anl.gov>*>*
>    Sent by: *mpi-forum-bounces at lists.mpi-forum.org*<mpi-forum-bounces at lists.mpi-forum.org>
>
>
>    06/26/2012 11:14 AM
>
>
>
>  Please respond to
>
> Main MPI Forum mailing list <*mpi-forum at lists.mpi-forum.org*<mpi-forum at lists.mpi-forum.org>
> >
>   To
>
>    Main MPI Forum mailing list <*mpi-forum at lists.mpi-forum.org*<mpi-forum at lists.mpi-forum.org>>,
>
>
>  cc
>  Subject
>
>
>    Re: [Mpi-forum] C++ types inaccessible after #281
>
>
>
>    On Tue, Jun 26, 2012 at 6:13 AM, Jeff Squyres <*jsquyres at cisco.com*<jsquyres at cisco.com>>
>    wrote:
>       There are a few C++-specific datatypes for which it would be worth
>       introducing new C datatypes (e.g., MPI_CXX_COMPLEX).  It's too bad that no
>       one realized this until now, because this won't make the MPI-3 deadline.
>        But it could be part of MPI-3.1 or errata, or some such.
>
>    Two people in offline discussions have suggested that C bindings to
>    the std::complex types (I'm not aware of anything else that #281 will lose)
>    might qualify as ticket 0.
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>
> --
> Jeff Hammond
> Argonne Leadership Computing Facility
> University of Chicago Computation Institute*
> **jhammond at alcf.anl.gov* <jhammond at alcf.anl.gov> / (630) 252-5381*
> **http://www.linkedin.com/in/jeffhammond*<http://www.linkedin.com/in/jeffhammond>
> *
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> *https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond*<https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond>
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-- 
Jeff Hammond
Argonne Leadership Computing Facility
University of Chicago Computation Institute
jhammond at alcf.anl.gov / (630) 252-5381
http://www.linkedin.com/in/jeffhammond
https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond
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