[Mpi-forum] MPI Count proposal from today's meeting

[Fab Tillier]

Hello everyone,

Yesterday, we discussed the direction we want to take to support large counts.

We reviewed the various plans that were presented since ticket #14 was originally introduced in September 2008.  We then put up for a straw vote the following plan:

Define MPI_Count in all existing APIs that use an int count.  Implementations will decide whether to define MPI_Count as a C int, or something larger.  Defining MPI_Count as a C int provides for backward compatibility with MPI 2.2 applications.  Defining it as a 64-bit integer lets an implementation support large counts.  Demand can drive which modes implementers will support.

Results of the straw vote were 19 for, 2 abstain, 0 against.

I'll be creating a ticket for this, hopefully have something by October.

Cheers,
-Fab