#define VISERR(vv) ((vv)->err != 0) /* have we seen an error yet? */
#define ISERR() VISERR(v)
#define VERR(vv,e) (((vv)->err) ? (vv)->err : ((vv)->err = (e)))
-#define ERR(e) VERR(v, e) /* record an error */
+#define ERR(e) (void)VERR(v, e) /* record an error */
#define NOERR() {if (ISERR()) return v->err;} /* if error seen, return it */
#define OFF(p) ((p) - v->start)
#define LOFF(p) ((long)OFF(p))