Hi all, With GCC 3.4.6, when compiling this simple program, (in tuple_test.cc) 1: #include <boost/tuple/tuple.hpp> 2: typedef const boost::tuple<> tuple; 3: const int size = boost::tuples::length<tuple>::value; 4: int main() {} I get /usr/local/include/boost/tuple/detail/tuple_basic.hpp: In instantiation of `boost::tuples::length<const tuple>': tuple_test.cc:3: instantiated from here /usr/local/include/boost/tuple/detail/tuple_basic.hpp:483: error: no type named `tail_type' in `const class tuple' If i remove "const" from line 2, the program compiles fine. It also compiles if line 2 is substituted with: "typedef const boost::tuple<int> tuple;" I think that 'length' not working with const empty tuples is clearly a bug. Shouldn't 'boost::tuples::length' need to be specialized for 'const tuple<>' in addition to 'tuple<>'? -- Giovanni P. Deretta