[mpich-discuss] Q: Why doesn't "use mpi, only : mpi_bcast" (or similar) work in MPICH?

[Brian Dobbins]

Hi all,

  I figure this is one of those things in the standard, but I figured I'd
get a better explanation asking here than digging through that myself.

  Long story short, if I try the following code:

*program foo*
*  use mpi, only: mpi_bcast*
*end program foo*

  ... This fails to compile in MPICH (3.4.2, at least), IntelMPI and
MVAPICH, but *does* work on OpenMPI and SGI MPT, at least on systems I've
tried.  Replacing the 'use, only' with just a 'use' directive works fine.
And MPI_BCAST is just an example here; things like 'MPI_Finalize' and
'MPI_Integer' appear to be in the module, but MPI_Send also fails.  Is this
a scenario where the standard doesn't support this, but OpenMPI and MPT do
it as a matter of convenience vs strict adherence found in the MPICH-based
libraries?  Or am I missing some simple issue?

  Any insight would be greatly appreciated!

  Thanks,
  - Brian
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mpich.org/pipermail/discuss/attachments/20210601/af27b299/attachment.html>