[boost] [threadpool] determining whether a Threadpool type uses a priority/attribute

Hello, Suppose I have a Threadpool type, which could for example be either of the following: tp::pool< tp::fixed, tp::unbounded_channel< tp::priority< int > > > -or- tp::pool< tp::fixed, tp::unbounded_channel< tp::fifo > > How do I find out whether Threadpool involves a priority/attribute, and what the type of it is? For example, I am looking for something that would give me: // returns something like mpl::true_ for the first case // returns something like mpl::false_ for the second case has_priority<Threadpool>::type // returns int for the first case priority_type<Threadpool>::type Thanks in advance, Stjepan