undiag_2reason_str
static char *undiag_2reason_str(int ud, char *arg);
reason = undiag_2reason_str(Undiag_reason, NULL);
char *reason = undiag_2reason_str(Undiag_reason, arg);
char *reason = undiag_2reason_str(Undiag_reason, NULL);
reason = undiag_2reason_str(Undiag_reason, NULL);