Pavel Antokolsky aka Zigmar wrote:
'T' is deduced to a function /pointer/. You have to use the plain function type (without the pointer on top) for 'function_traits' to work:
typedef typename boost::function_traits< typename boost::remove_pointer<T>::type >::result_type X; Ah, thanks. That what I've been missing. I can of course "remove_pointer", but what I'm wandering, is why the function_traits tries to add pointer in a first place?
It's done to please broken compilers, I guess. Further, usually you want to accept both function objects and function pointers: template<typename R, typename F> void foo_impl(F f); template<class F> inline void foo(F f) { typedef typename F::result_type result; foo_impl<result>(f); } template<typename F> inline void foo(F * f) { typedef typename boost::function_traits<F>::result_type result; foo_impl<result>(f); } And if done like this, the function type is deduced without a pointer. Regards, Tobias