diff --git a/include/boost/range/detail/implementation_help.hpp b/include/boost/range/detail/implementation_help.hpp
index 77cc8cc..11c6612 100755
--- a/include/boost/range/detail/implementation_help.hpp
+++ b/include/boost/range/detail/implementation_help.hpp
@@ -43,7 +43,7 @@ namespace boost
 #else
         inline const wchar_t* str_end( const wchar_t* s, const wchar_t* )
         {
-            if( s == 0 && s[0] == 0 )
+            if( s == 0 || s[0] == 0 )
                 return s;
             while( *++s != 0 )
                 ;