Hi, Newbie question follows... I've used BOOST_MPL_HAS_XXX_TRAIT_DEF in the past but recently needed to determine if a function was defined with a given signature. Searching boost::mpl, stackoverflow etc, I couldn't find anything to do what I needed. I've attached my solution below. Basically, I'm wondering if there is a boost::mpl solution or some other more elegant solution. thanks, andrew #include <boost/mpl/bool.hpp> #include <boost/mpl/assert.hpp> #define XXX_DEFINED(symbol) \ template <typename T, T* = symbol> \ struct check_ ## symbol \ { \ typedef void type; \ }; \ \ template <typename T, typename enable = void> \ struct symbol ## _defined : \ boost::mpl::false_ \ { }; \ \ template <typename T> \ struct symbol ## _defined<T, typename check_ ## symbol<T>::type > : \ boost::mpl::true_ \ { }; // declare a some_func(int) so we can see if its declared... void some_func(int) {} // defines some_func_defined template XXX_DEFINED(some_func); BOOST_MPL_ASSERT(( some_func_defined<void(int)> )); // some_func(double) hasn't been declared BOOST_MPL_ASSERT_NOT(( some_func_defined<void(double)> ));