unknown_prefix    186 ompi/errhandler/errhandler_predefined.c     const char* const unknown_prefix = "[?:?]";
unknown_prefix    192 ompi/errhandler/errhandler_predefined.c     const char* usable_prefix = unknown_prefix;
unknown_prefix    222 ompi/errhandler/errhandler_predefined.c     usable_prefix  = (NULL == prefix)  ? unknown_prefix : prefix;