diff -r 320b962afaf9 -r 6089eb30a51a src/ucx/array.h
--- a/src/ucx/array.h	Wed Aug 07 20:45:21 2019 +0200
+++ b/src/ucx/array.h	Wed Aug 07 21:14:58 2019 +0200
@@ -234,8 +234,12 @@
 /**
  * Sorts a UcxArray with the best available sort algorithm.
  * 
- * A merge sort algorithm is used, which is guaranteed to use no more additional
- * memory than for exactly one element.
+ * The qsort_r() function is used, if available (glibc, FreeBSD or MacOS).
+ * The order of arguments is automatically adjusted for the FreeBSD and MacOS
+ * version of qsort_r().
+ * 
+ * If qsort_r() is not available, a merge sort algorithm is used, which is
+ * guaranteed to use no more additional memory than for exactly one element.
  * 
  * @param array the array to sort
  * @param cmpfnc the function that shall be used to compare the element data