diff -r aeaf7db26fac -r c094afcdfb27 src/ucx/cx/list.h
--- a/src/ucx/cx/list.h	Sun Jul 09 15:14:26 2023 +0200
+++ b/src/ucx/cx/list.h	Mon Jul 10 18:39:24 2023 +0200
@@ -70,11 +70,14 @@
 struct cx_list_class_s {
     /**
      * Destructor function.
+     *
+     * Implementations SHALL invoke the content destructor functions if provided
+     * and SHALL deallocate the list memory, if an allocator is provided.
      */
     void (*destructor)(struct cx_list_s *list);
 
     /**
-     * Member function for inserting a single elements.
+     * Member function for inserting a single element.
      * Implementors SHOULD see to performant implementations for corner cases.
      */
     int (*insert_element)(
@@ -142,7 +145,7 @@
     );
 
     /**
-     * Member function for sorting the list in place.
+     * Member function for sorting the list in-place.
      */
     void (*sort)(struct cx_list_s *list);
 
@@ -581,7 +584,7 @@
 }
 
 /**
- * Sorts the list in place.
+ * Sorts the list in-place.
  *
  * \remark The underlying sort algorithm is implementation defined.
  *
@@ -632,6 +635,14 @@
 __attribute__((__nonnull__))
 void cxListDestroy(CxList *list);
 
+/**
+ * A shared instance of an empty list.
+ *
+ * Writing to that list is undefined.
+ */
+extern CxList * const cxEmptyList;
+
+
 #ifdef __cplusplus
 } // extern "C"
 #endif