diff -r 11f3bb408051 -r 62921b370c60 ucx/ucx.h
--- a/ucx/ucx.h	Wed Nov 22 12:59:13 2017 +0100
+++ b/ucx/ucx.h	Sun Jan 21 12:13:09 2018 +0100
@@ -1,7 +1,7 @@
 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
- * Copyright 2015 Olaf Wintermann. All rights reserved.
+ * Copyright 2016 Olaf Wintermann. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -40,12 +40,10 @@
 #define UCX_VERSION_MAJOR   0
 
 /** Minor UCX version as integer constant. */
-#define UCX_VERSION_MINOR   9
-
-/** The UCX version in format [major].[minor] */
-#define UCX_VERSION UCX_VERSION_MAJOR.UCX_VERSION_MINOR
+#define UCX_VERSION_MINOR   12
 
 #include <stdlib.h>
+#include <stdint.h>
 
 #ifdef _WIN32
 #if !(defined __ssize_t_defined || defined _SSIZE_T_)
@@ -89,7 +87,16 @@
  * and 0 if both arguments are equal. If the third argument is
  * <code>NULL</code>, it shall be ignored.
  */
-typedef int(*cmp_func)(void*,void*,void*);
+typedef int(*cmp_func)(const void*,const void*,void*);
+
+/**
+ * Function pointer to a distance function.
+ * 
+ * The distance function shall take three arguments: the two values for which
+ * the distance shall be computed and optional additional data.
+ * The function shall then return the signed distance as integer value.
+ */
+typedef intmax_t(*distance_func)(const void*,const void*,void*);
 
 /**
  * Function pointer to a copy function.
@@ -102,7 +109,7 @@
  * passed to <code>free()</code> depends on the implementation of the
  * respective <code>copy_func</code>.
  */
-typedef void*(*copy_func)(void*,void*);
+typedef void*(*copy_func)(const void*,void*);
 
 /**
  * Function pointer to a write function.