Rob Latham <[email protected]> writes:

i imagine one day (once again?) the c int type will be 64 bits on a platform, right?

or will c ints be 32 bits for ever?

2^64 is quite a lot of memory. The popular 64-bit systems use LP64 or LLP64, both of which have 32-bit ints. I don't foresee any major player having incentive to promote int to 64-bits. I think it's worth fixing this interface problem _and_ fixing the MPI_Op support so that libraries can build robust abstractions. (I have example use cases in PETSc that caused a bit of discussion including the creation of ticket #338, and now Jeff has another.)