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 <[email protected]> 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.

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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 <*[email protected]*<[email protected]>> 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).

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On Tue, Jun 26, 2012 at 6:13 AM, Jeff Squyres <*[email protected]*<[email protected]>> 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. _______________________________________________ mpi-forum mailing list* **[email protected]* <[email protected]>* **http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum*<http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum>

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