I will file a proposal about this if there is a problem, but I wanted to ask the group before I did so. In the changelog for MPI-2.1: 2. Section 3.2.2 on page 27, Section 16.1.6 on page 453, and Annex A.1 on page 491. MPI_LONG_LONG_INT, MPI_LONG_LONG (as synonym), MPI_UNSIGNED_LONG_LONG, MPI_SIGNED_CHAR, and MPI_WCHAR are moved from optional to official and they are therefore deï¬ned for all three language bindings. Note that it says that these C datatype names must be in all three language bindings. Are C MPI datatypes supposed to be available in Fortran? I looked in mpif.h for Open MPI, MPICH2, HP MPI, and Intel MPI, and I didn't see C MPI datatypes in there (e.g., MPI_INT and MPI_FLOAT). So: - is there language somewhere in MPI that says that C datatypes are not supposed to be in mpif.h? (and therefore the MPI-2.1 changelog is wrong) or - are all 4 of the above MPI's wrong for not including the C datatypes in mpif.h? -- Jeff Squyres Cisco Systems