On Tue, Jun 26, 2012 at 10:43 AM, Douglas Miller
<dougmill@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?
Is there an informal expectation that implementations will continue to provide an mpicxx wrapper?
I see no reason for anyone to be attached to std::complex (actually, I think it's very frequently a bad choice), but having *some* way to use complex types with a predefined (because one-sided cripples non-predefined) MPI_Op still seems important.
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.
As mentioned earlier, implementations making MPI_C_COMPLEX available independent of C99 would be sufficient. Otherwise we are stuck defining our own types for complex, and then can't use one-sided.