[Debichem-devel] Bug#1075979: [Help] molds: FTBFS with mpich as default MPI provider: /usr/bin/ld: cannot find -lmpi_cxx: No such file or directory

[Andreas Tille]

Control: tags -1 - help
Control: tags -1 pending
Thanks

Am Fri, Nov 08, 2024 at 09:11:51PM +0100 schrieb Drew Parsons:
> We're in the middle of transitioning to OpenMPI 5.  OpenMPI 5 removed
> libmpi_cxx, which is why this bug happened.
> 
> Bill is certainly right, -lstdc++ -lmpi -lmpi_cxx should not be hardcoded in
> build rules.
> and just using mpicxx is the simplest method.

Thanks to you and Bill for the helpful hints.
 
> But Build-Depends: libopenmpi-dev is also wrong, unless the program is badly
> written and not conformant with the MPI standard.  openmpi 5 does not build
> on 32-bit arches, so we use mpich.
> 
> Build-Depends: mpi-default-dev is the correct dependency
> (alongside removing the hardcoded -lmpi -lmpi_cxx and using CXX=mpicxx)

Thank you for clarifying this.

Kind regards
   Andreas. 

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