- fixed problems deallocation sicsobjects

SCinter.c

@@ -450,12 +450,11 @@ void DeleteInterp(SicsInterp * self)
   if (tail) {
     pCurrent = tail;
     while (pCurrent) {
-      /* the line below fixes problems with kill functions 
-       * traversing the command list
-       */
-      pCurrent->pNext = NULL;
+      pCurrent->pNext = NULL; /* inhibit access to killed commands by FindCommandData */
       if (pCurrent->KFunc) {
-        pCurrent->KFunc(pCurrent->pData);
+        void *data = pCurrent->pData;
+        pCurrent->pData = NULL; /* make data unreachable by FindCommandData before killing */
+        pCurrent->KFunc(data);
       }
       if (pCurrent->pName) {
         /* printf("Deleting %s\n",pCurrent->pName); */