diff -r 0923c036b913 -r f819fe5e20f5 src/list.c
--- a/src/list.c	Tue Jan 23 19:23:34 2018 +0100
+++ b/src/list.c	Wed May 02 16:14:40 2018 +0200
@@ -77,6 +77,7 @@
 }
 
 void ucx_list_free_content(UcxList* list, ucx_destructor destr) {
+    if (!destr) destr = free;
     while (list != NULL) {
         destr(list->data);
         list = list->next;