Unfortunately I found code snippets like this:
``` static int child_init(int rank) { int i, j; int len; xhttp_rpc_mod_cmds_t *cmds; /* rpc_export_t *rpc_e; */
if(rank==PROC_MAIN || rank==PROC_TCP_MAIN) return 0; /* do nothing for the main process */ ```
So some modules are "aware" of which ranks refer to the main process.