--- ray/src/gen/mkillum2.c	1991/08/26 10:16:56	1.13
+++ ray/src/gen/mkillum2.c	1991/11/08 13:17:47	1.14
@@ -291,6 +291,7 @@ register struct rtproc  *rt;
 	if (rt->nrays <= 0)
 		return;
 	bzero(rt->buf+6*rt->nrays, 6*sizeof(float));
+	errno = 0;
 	if ( process(rt->pd, (char *)rt->buf, (char *)rt->buf,
 			3*sizeof(float)*rt->nrays,
 			6*sizeof(float)*(rt->nrays+1)) <