diff --git a/sdk/lib/atl/atlcoll.h b/sdk/lib/atl/atlcoll.h
index 1068deeacc5..8351a3a6f56 100644
--- a/sdk/lib/atl/atlcoll.h
+++ b/sdk/lib/atl/atlcoll.h
@@ -480,6 +480,9 @@ public:
     POSITION AddHead(INARGTYPE element);
     POSITION AddTail(INARGTYPE element);
 
+    void AddHeadList(_In_ const CAtlList<E, ETraits>* plNew);
+    void AddTailList(_In_ const CAtlList<E, ETraits>* plNew);
+
     E RemoveHead();
     E RemoveTail();
 
@@ -639,6 +642,24 @@ POSITION CAtlList<E, ETraits>::AddTail(INARGTYPE element)
     return (POSITION)Node;
 }
 
+template <typename E, class ETraits>
+void CAtlList<E, ETraits>::AddHeadList(_In_ const CAtlList<E, ETraits>* plNew)
+{
+    ATLASSERT(plNew != NULL && plNew != this);
+    POSITION pos = plNew->GetTailPosition();
+    while (pos)
+        AddHead(plNew->GetPrev(pos));
+}
+
+template <typename E, class ETraits>
+void CAtlList<E, ETraits>::AddTailList(_In_ const CAtlList<E, ETraits>* plNew)
+{
+    ATLASSERT(plNew != NULL && plNew != this);
+    POSITION pos = plNew->GetHeadPosition();
+    while (pos)
+        AddTail(plNew->GetNext(pos));
+}
+
 template<typename E, class ETraits>
 E CAtlList<E, ETraits>::RemoveHead()
 {