diff -r 6367456bf2d9 -r 558ed4c6abd0 src/cx/tree.h
--- a/src/cx/tree.h	Wed Jul 03 22:07:42 2024 +0200
+++ b/src/cx/tree.h	Sun Jul 07 12:21:58 2024 +0200
@@ -404,6 +404,49 @@
         ptrdiff_t loc_next
 );
 
+/**
+ * Describes a function that creates a tree node from the specified data.
+ */
+typedef void (*cx_tree_node_create_fun)(void const*);
+
+__attribute__((__nonnull__))
+size_t cx_tree_add_iter(
+        struct cx_iterator_base_s *iter,
+        cx_tree_search_func sfunc,
+        cx_tree_node_create_fun cfunc,
+        void **root,
+        ptrdiff_t loc_parent,
+        ptrdiff_t loc_children,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next
+);
+
+__attribute__((__nonnull__))
+size_t cx_tree_add_array(
+        void const *src,
+        size_t num,
+        size_t elem_size,
+        cx_tree_search_func sfunc,
+        cx_tree_node_create_fun cfunc,
+        void **root,
+        ptrdiff_t loc_parent,
+        ptrdiff_t loc_children,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next
+);
+
+__attribute__((__nonnull__))
+void *cx_tree_add(
+        void const *src,
+        cx_tree_search_func sfunc,
+        cx_tree_node_create_fun cfunc,
+        void **root,
+        ptrdiff_t loc_parent,
+        ptrdiff_t loc_children,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next
+);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif