diff --git a/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.h b/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.h
index 03c384690ff2a082450b55da89eefaabd1092ba2..01bec029f011622b27710732e999a0f6482beec9 100644
--- a/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.h
+++ b/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.h
@@ -313,9 +313,11 @@ public:
    * @param ptr Payload for this element.
    * @param ctx Execution context.
    *
-   * Returns true if the new element was successfully inserted.
-   * Returns false if the range compared equal to an existing one. In that case,
+   * Returns SUCCESS if the new element was successfully inserted.
+   * Returns DUPLICATE if the range compared equal to an existing one. In that case,
    * no new element is inserted (and @c ptr gets deleted).
+   * Returns OVERLAP if the range of the new element overlaps
+   * an existing element (the new element is still inserted).
    */
   EmplaceResult emplace (const RANGE& range,
                          payload_unique_ptr ptr,
diff --git a/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.icc b/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.icc
index c88dd789cc2be0db5724e0b2be1cf910c0574a04..d9e999ebd10b0d3e97c3e7d4d47b7904bd617bff 100644
--- a/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.icc
+++ b/Control/CxxUtils/CxxUtils/ConcurrentRangeMap.icc
@@ -165,9 +165,11 @@ CONCURRENTRANGEMAP::find (const key_query_type& key) const
  * @param ptr Payload for this element.
  * @param ctx Execution context.
  *
- * Returns true if the new element was successfully inserted.
- * Returns false if the range compared equal to an existing one. In that case,
+ * Returns SUCCESS if the new element was successfully inserted.
+ * Returns DUPLICATE if the range compared equal to an existing one. In that case,
  * no new element is inserted (and @c ptr gets deleted).
+ * Returns OVERLAP if the range of the new element overlaps
+ * an existing element (the new element is still inserted).
  */
 T_CONCURRENTRANGEMAP
 typename CONCURRENTRANGEMAP::EmplaceResult