--- a/src/parallel_execution/SingleLinkedQueue.cbc	Wed Jan 27 16:52:11 2021 +0900
+++ b/src/parallel_execution/SingleLinkedQueue.cbc	Wed Jan 27 17:06:14 2021 +0900
@@ -103,17 +103,17 @@
 } TaskIterator, *TaskIteratorPtr;
 
 
-TaskIteratorPtr createQueueIterator(struct SingleLinkedQueue* queue, struct Element* prev) {
+TaskIteratorPtr createQueueIterator(struct SingleLinkedQueue* queue, StateDB s, struct Element* prev) {
     TaskIteratorPtr new = (TaskIteratorPtr)calloc(1, sizeof(TaskIterator));
     if (!new) exit(1);
     new->prev  = prev;
-    new->state = NULL;
+    new->state = s; //
     new->list  = queue->top;
     new->last  = queue->last;
     return new;
 }
 
-TaskIteratorPtr takeNextIterator(struct SingleLinkedQueue* queue, TaskIteratorPtr iterator) {
+Element* takeNextIterator(struct SingleLinkedQueue* queue, TaskIteratorPtr iterator) {
   struct Element* elem = iterator->list;
   if (!elem) {
     return NULL;
@@ -128,7 +128,6 @@
     return NULL;
   }
 
-  iterator->prev = elem;
   iterator->list = next;
-  return iterator;
+  return next;
 }