Zero size in argument to gdh_RefObjectInfo caused segfault

src/lib/rt/src/rt_gdh.c

 /* 
- * Proview   $Id: rt_gdh.c,v 1.20 2005-10-12 12:59:35 claes Exp $
+ * Proview   $Id: rt_gdh.c,v 1.21 2005-11-03 12:29:39 claes Exp $
  * Copyright (C) 2005 SSAB Oxelsund AB.
  *
  * This program is free software; you can redistribute it and/or 
@@ -2806,6 +2806,8 @@ gdh_RefObjectInfoList (
     /* Associate buffers and return pwr_tSubid if requested.  */
 
     for (i=0; i<nsub; i++) {
+      if ( objrefp->bufsize == 0)
+	return GDH__BADARG;
       objrefp = &objref[xrefarr[i]];
       gdh_SubAssociateBuffer(subidarr[i], &objrefp->adrs, objrefp->bufsize);
       if (sid != NULL) sid[xrefarr[i]] = subidarr[i];