--- a/src/array_t.cpp	2017-09-17 00:51:49.983706157 -0400
+++ b/src/array_t.cpp	2017-09-17 00:51:57.155899534 -0400
@@ -185,7 +185,7 @@
     : actual(rhs), m_begin((T*)(rhs->begin())), m_end((T*)(rhs->end())) {
     if (actual != 0)
         actual->beginUse();
-    difference_type diff = m_end - m_begin;
+    //difference_type diff = m_end - m_begin;
 
     LOGGER(ibis::gVerbose > 9)
         << "array_t<" << typeid(T).name() << "> constructed at "