The "epicycle" screenhack will dump core when given the option
"-max_circles 2".

NOTE: This affects all versions of xscreensaver since 2.18.

The following patch fixes this:-




diff -u -r1.1 xscreensaver-3.22/hacks/epicycle.c
--- xscreensaver-3.22/hacks/epicycle.c  2000/01/26 22:36:21     1.1
+++ xscreensaver-3.22/hacks/epicycle.c  2000/01/26 22:39:58
@@ -266,7 +266,10 @@

   /* There are between minCircles and maxCircles in each figure.
    */
-  n = minCircles + random() % (maxCircles - minCircles);
+  if (maxCircles == minCircles)
+    n = minCircles;            /* Avoid division by zero. */
+  else
+    n = minCircles + random() % (maxCircles - minCircles);

   head = NULL;
   while (n--)