diff -r 0923c036b913 -r f819fe5e20f5 src/ucx/map.h
--- a/src/ucx/map.h	Tue Jan 23 19:23:34 2018 +0100
+++ b/src/ucx/map.h	Wed May 02 16:14:40 2018 +0200
@@ -158,7 +158,10 @@
  * Frees the contents of a hash map.
  * 
  * This is a convenience function that iterates over the map and passes all
- * values to the specified destructor function (e.g. stdlib free()).
+ * values to the specified destructor function.
+ * 
+ * If no destructor is specified (<code>NULL</code>), the free() function of
+ * the map's own allocator is used.
  * 
  * You must ensure, that it is valid to pass each value in the map to the same
  * destructor function.
@@ -166,7 +169,7 @@
  * You should free or clear the map afterwards, as the contents will be invalid.
  * 
  * @param map for which the contents shall be freed
- * @param destr pointer to the destructor function
+ * @param destr optional pointer to a destructor function
  * @see ucx_map_free()
  * @see ucx_map_clear()
  */