To: J3                                                     J3/23-228
From: Jeff Hammond
Subject: MPI Liason Report
Date: 2023-October-16

We are doing final reviews of MPI 4.1.  Most feature development
is on hold while we finish this release of the standard.

There was a vigorous debate about the new API functions [1] that
are less pleasant to use from Fortran because of the differences
in integer type promotion between C and Fortran.
Only the large-count signature was added, which is fine for C
users but means that one cannot pass an integer literal like
"1" to the count argument.  Rather, it must be explicitly cast
to something equivalent to INT(1,KIND=MPI_COUNT_KIND).
The MPI Forum recognized that this is an annoyance for Fortran
users and will fix it in MPI 4.2.

I have made progress on the Fortran aspects of the MPI ABI
specification that is targeting MPI 4.2.

1. https://github.com/mpi-forum/mpi-issues/issues/765