I just filed ticket 55, about example 16.17 in MPI-2.1 p487: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/55 The last line of the second sub-example is wrong, but I think the examples themselves are extremely subtle and are worth both making more explicit and adding some comments. More details are available on the ticket. I've asked several people for reviews already. Enjoy. -- Jeff Squyres Cisco Systems