diff -r d5d6ab809ad3 -r deb0035635eb src/ucx/list.h
--- a/src/ucx/list.h	Wed May 09 20:15:10 2018 +0200
+++ b/src/ucx/list.h	Fri May 11 17:40:16 2018 +0200
@@ -232,8 +232,6 @@
  * Inserts an element at the end of the list, if it is not present in the list,
  * using a UcxAllocator.
  * 
- * See ucx_list_append() for details.
- * 
  * @param allocator the allocator to use
  * @param list the list where to append the data, or <code>NULL</code> to
  * create a new list
@@ -248,6 +246,38 @@
         UcxList *list, void *data, cmp_func cmpfnc, void *cmpdata);
 
 /**
+ * Inserts an element at the beginning of the list, if it is not present
+ * in the list.
+ * 
+ * 
+ * @param list the list where to prepend the data, or <code>NULL</code> to
+ * create a new list
+ * @param data the data to insert
+ * @param cmpfnc the compare function
+ * @param cmpdata additional data for the compare function
+ * @return a pointer to the new list head
+ * @see ucx_list_prepend()
+ */
+UcxList *ucx_list_prepend_once(UcxList *list, void *data,
+        cmp_func cmpfnc, void *cmpdata);
+
+/**
+ * Inserts an element at the beginning of the list, if it is not present in
+ * the list, using a UcxAllocator.
+ * 
+ * @param allocator the allocator to use
+ * @param list the list where to prepend the data, or <code>NULL</code> to
+ * create a new list
+ * @param data the data to insert
+ * @param cmpfnc the compare function
+ * @param cmpdata additional data for the compare function
+ * @return a pointer to the new list head
+ * @see ucx_list_prepend_a()
+ */
+UcxList *ucx_list_prepend_once_a(UcxAllocator *allocator,
+        UcxList *list, void *data, cmp_func cmpfnc, void *cmpdata);
+
+/**
  * Inserts an element at the beginning of the list.
  * 
  * You <i>should</i> overwrite the old list pointer by calling