Hi James, >> the easiest way is something like the following: >> >> #include <boost/type_traits.hpp> >> #include <boost/static_assert.hpp> >> >> BOOST_STATIC_ASSERT (boost::is_base_of<Base, Derived>::value); >> >> Hope this helps, >> >> Martin >> > > Thanks Martin - I knew I had seen it somewhere. > > That covers the first point, but I've just realised I need to be a bit > cleverer. The incoming type can either be the type itself or a pointer > to the type, or a boost::shared_ptr to the type, and the type must be > derived as the original question. Depending on which it is I need to do > slightly different things, so I need to, effectively, conditionally > compile a bit of code depending on the results of the tests, or assert > if the type (after getting rid of the pointer/shared point bit) isn't > derived from my base class. > > Basically I'm iterating through a vector of the incoming type and > calling a function in the type stored. That function comes from the base > class, but in order to be really generic I need to handle the shared_ptr > and pointer cases. > > I think I need mpl for that, but I only get to chapter three of the book > before my head starts to hurt. Any ideas/hints/places I can look? > > I'm not sure if you really need mpl to do this. To me it looks as if you need one template and multiple partial specialization, something like the following: template<typename T> class Handler { public: void doIt (T val) { .... // default implementation } }; template<typename T> class Handler<boost::shared_ptr<T> > { public: void doIt (boost::shared_ptr<T> val) { ... // Impl for shared_ptr } template <typename T> class Handler<T*> .... Hope this helps, Martin _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users Actually you can use only one Handler class and some templated function overloads: template<class Base> class Hanlder { template<class Derived> void do_it(T const& t, typename boost::enable_if< boost::is_base_of<Base, T> >::type*=0) { //do smth. } template<class Derived> void do_it(boost::shared_ptr<T> t, typename boost::enable_if< boost::is_base_of<Base, T> >::type*=0) { //do smth. } .... }; Thanks Martin and Ovanes, I think you have put me on the right track there. Much appreciated. James This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.