Actually, I thought about this more. There is a way to not break ABI, but still adhere to MPI-3.
Let me go work up a patch and see if it's horrible; I think it will be a matter of reverting *some* of the code, but not *all* of it. On Jan 28, 2014, at 5:35 PM, Jeff Squyres <jsquy...@cisco.com> wrote: > It looks like Past Jeff was wrong: the removal of the choice buffers from the > non-ignore-TKR version of the Fortran mpi module (which is only used for > gfortran <=v4.8) *does* cause ABI breakage between 1.7.3 and 1.7.4. > > Per discussion on the telconf today, we decided that we're going to do this > anyway, because it's an MPI-3.0 conformance issue. > > I've added the following to the README in the ABI section: > > * A second bug was discovered after v1.7.3 was released that causes > ABI to be broken for gfortran users who are using the "mpi" Fortran > module. In short, for versions of gfortran that do not support > "ignore TKR" functionality (i.e., gfortran <=v4.8), Open MPI was > providing interfaces for MPI subroutines with choice buffers (e.g., > MPI_Send) in the Fortran mpi module. The MPI-3.0 specification > expressly states not to do this. To be consistent with MPI-3, Open > MPI v1.7.4 therefore removed all MPI interfaces with choice buffers > from the no-ignore-TKR version of the Fortran mpi module, even > though this breaks ABI between v1.7.3 and v1.7.4. Affected users > should be able to recompile their MPI applications with v1.7.4 with > no changes. > > Other Fortran compilers that provide "ignore TKR" functionality are > not affected by this change. > > -- > Jeff Squyres > jsquy...@cisco.com > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
