Jeff Squyres wrote:

You're right, I was not checking 2.1 implementations.

While 2.1 changelog item 2 does specifically mention those constants in all 3 languages, what about the other datatypes? (e.g., MPI_INT vs. MPI_INTEGER, etc.?)

MPI-2.1 Section 16.3.6 MPI Opaque Objects, page 483, lines 46-47: "All predefined datatypes can be used in datatype constructors in any language." *