It appears that an enum cannot be default constructed in the way that tuple does, cons() : head(), tail() {} Any idea on how to get around this (besides using an int in the tuple)? Thanks, Tom <sample_code> #include <boost/tuple/tuple.hpp> #include <string> enum Foo { Willis, Arnold }; void test() { boost::tuple<Foo, std::string> a; } </sample_code> </error compiler="gcc version 2.96 20000731 (Mandrake Linux 8.2)"> /usr/local/eddynet/opt/include/boost/tuple/detail/tuple_basic.hpp: In method `boost::tuples::cons<HT, TT>::cons () [with HT = Foo, TT = boost::tuples::cons<string, boost::tuples::null_type>]': /usr/local/eddynet/opt/include/boost/tuple/detail/tuple_basic.hpp:454: instantiated from `boost::tuples::tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::tuple () [with T0 = Foo, T1 = string, T2 = boost::tuples::null_type, T3 = boost::tuples::null_type, T4 = boost::tuples::null_type, T5 = boost::tuples::null_type, T6 = boost::tuples::null_type, T7 = boost::tuples::null_type, T8 = boost::tuples::null_type, T9 = boost::tuples::null_type]' tuple_enum_test.cpp:8: instantiated from here /usr/local/eddynet/opt/include/boost/tuple/detail/tuple_basic.hpp:263: cannot convert `int' to `Foo' in assignment </error> ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------