Oh bugger, I did miss the obvious. The "old" code which I had ifdef'd out contained an actual construction of the list itself.
OBJ_CONSTRUCT(&opal_if_list, opal_list_t); If I make sure I do one of those, I now get a different set of messages but we are back to running again. mpirun -v -n 1 hello_f77 About to append interface wm0. Appended interface wm0. [europa.ecs.vuw.ac.nz:12741] opal_sockaddr2str failed:Temporary failure in name resolution (return code 4) [europa.ecs.vuw.ac.nz:12741] opal_sockaddr2str failed:Temporary failure in name resolution (return code 4) [europa.ecs.vuw.ac.nz:12741] opal_sockaddr2str failed:Temporary failure in name resolution (return code 4) [europa.ecs.vuw.ac.nz:12741] opal_sockaddr2str failed:Temporary failure in name resolution (return code 4) [europa.ecs.vuw.ac.nz:12741] oob_tcp_parse_uri: Could not resolve (null). [Error: No address associated with hostname] About to append interface wm0. Appended interface wm0. [europa.ecs.vuw.ac.nz:15348] oob_tcp_parse_uri: Could not resolve (null). [Error: No address associated with hostname] [europa.ecs.vuw.ac.nz:15348] opal_sockaddr2str failed:Success (return code 4) Hello, world, I am 0 of 1 [europa.ecs.vuw.ac.nz:15348] opal_sockaddr2str failed:Success (return code 4) We're getting there. -- Kevin M. Buckley Room: CO327 School of Engineering and Phone: +64 4 463 5971 Computer Science Victoria University of Wellington New Zealand