Index: boost/operators.hpp
===================================================================
RCS file: /cvsroot/boost/boost/boost/operators.hpp,v
retrieving revision 1.14
diff -u -r1.14 operators.hpp
--- boost/operators.hpp	26 Feb 2003 21:26:57 -0000	1.14
+++ boost/operators.hpp	12 Mar 2003 18:58:40 -0000
@@ -302,6 +302,18 @@
   }
 };
 
+//  bool_testable (contributed by Sam Partington, David Abrahams, -----------//
+//  and Daniel Frey. Original concept taken from shared_ptr by Peter Dimov) -//
+
+template <class T, class B = ::boost::detail::empty_base>
+struct bool_testable : B
+{
+    friend bool operator!(const T& t)  { return !static_cast<bool>(t);    }
+private:
+    typedef signed char private_number_type;
+    operator private_number_type() const;
+};
+ 
 //  More operator classes (contributed by Daryle Walker) --------------------//
 //  (NRVO-friendly implementation contributed by Daniel Frey) ---------------//