Index: boost/tuple/tuple_io.hpp
===================================================================
--- boost/tuple/tuple_io.hpp	(revision 51856)
+++ boost/tuple/tuple_io.hpp	(working copy)
@@ -285,6 +285,21 @@
 } // namespace detail
 
 #if defined (BOOST_NO_TEMPLATED_STREAMS)
+
+inline std::ostream& operator<<(std::ostream& o, const null_type& t) {
+  if (!o.good() ) return o;
+ 
+  const char l = 
+    detail::format_info::get_manipulator(o, detail::format_info::open);
+  const char r = 
+    detail::format_info::get_manipulator(o, detail::format_info::close);
+   
+  o << l;
+  o << r;
+
+  return o;
+}
+
 template<class T1, class T2>
 inline std::ostream& operator<<(std::ostream& o, const cons<T1, T2>& t) {
   if (!o.good() ) return o;
@@ -305,6 +320,23 @@
 
 #else
 
+template<class CharType, class CharTrait>
+inline std::basic_ostream<CharType, CharTrait>& 
+operator<<(std::basic_ostream<CharType, CharTrait>& o, 
+           const null_type& t) {
+  if (!o.good() ) return o;
+ 
+  const CharType l = 
+    detail::format_info::get_manipulator(o, detail::format_info::open);
+  const CharType r = 
+    detail::format_info::get_manipulator(o, detail::format_info::close);
+   
+  o << l;
+  o << r;
+
+  return o;
+}
+
 template<class CharType, class CharTrait, class T1, class T2>
 inline std::basic_ostream<CharType, CharTrait>& 
 operator<<(std::basic_ostream<CharType, CharTrait>& o, 
Index: libs/tuple/test/io_test.cpp
===================================================================
--- libs/tuple/test/io_test.cpp	(revision 51856)
+++ libs/tuple/test/io_test.cpp	(working copy)
@@ -70,6 +70,15 @@
   os1 << make_tuple(1, 2, 3);
   BOOST_CHECK (os1.str() == std::string("[1,2,3][1,2,3]") );
 
+  // check empty tuple.
+  useThisOStringStream os3;
+  os3 << make_tuple();
+  BOOST_CHECK (os3.str() == std::string("()") );
+  os3 << set_open('[');
+  os3 << set_close(']');
+  os3 << make_tuple();
+  BOOST_CHECK (os3.str() == std::string("()[]") );
+
   ofstream tmp("temp.tmp");
 
 #if !defined (BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
@@ -98,13 +107,20 @@
 
 
   // reading tuple<int, int, int> in format (a b c); 
-  useThisIStringStream is("(100 200 300)"); 
+  useThisIStringStream is1("(100 200 300)"); 
    
-  tuple<int, int, int> ti; 
-  BOOST_CHECK(bool(is >> ti));
-  BOOST_CHECK(ti == make_tuple(100, 200, 300));
-   
+  tuple<int, int, int> ti1; 
+  BOOST_CHECK(bool(is1 >> ti1));
+  BOOST_CHECK(ti1 == make_tuple(100, 200, 300));
 
+  useThisIStringStream is2("()");
+  tuple<> ti2;
+  BOOST_CHECK(bool(is2 >> ti2));
+  useThisIStringStream is3("[]");
+  is3 >> set_open('[');
+  is3 >> set_close(']');
+  BOOST_CHECK(bool(is3 >> ti2));
+
   // Note that strings are problematic:
   // writing a tuple on a stream and reading it back doesn't work in
   // general. If this is wanted, some kind of a parseable string class