This is meant as library code, not application code, though for template work, this is actually quite lightweight. You'd see scarier creatures than this if you write C++ libraries. Perhaps you should take a look at the implementation of your standard libraries or your favourite boost library sometime.

Let's break it down:

If this weren't library code you mightn't care about proper forwarding (which isn't important anyway since the function you're calling is written in C and C doesn't have lvalue-references!! - unnecessary complexity), so you would sloppily write this as:

    template<typename Creator, typename Destructor, typename... Arguments>
    auto make_resource(Creator c, Destructor d, Arguments&&... args)
    {
        typedef decltype(*c(args...)) ResourceType;
        return std::unique_ptr<ResourceType, void(*)(ResourceType*)>(c(args...), d);
    }

Which is much easier to understand, yes? Your standard passing multiple arguments along thing like you'd normally do when writing a custom printf.

Actually, now that I've had time to think about it, you can simpify the original code:

    template<typename Creator, typename Destructor, typename... Arguments>
    auto make_resource(Creator c, Destructor d, Arguments&&... args)
    {
        auto r = c(std::forward<Arguments>(args...));
        typedef typename std::decay<decltype(*r)>::type ResourceType;
        return std::unique_ptr<ResourceType, void(*)(ResourceType*)>(r, d);
    }

And again, written sloppily:

    template<typename Creator, typename Destructor, typename... Arguments>
    auto make_resource(Creator c, Destructor d, Arguments&&... args)
    {
        auto r = c(args...);
        typedef decltype(*r) ResourceType;
        return std::unique_ptr<ResourceType, void(*)(ResourceType*)>(r, d);
    }

Or, if you don't mind repetition of ResourceType:

    template<typename Creator, typename Destructor, typename... Arguments>
    auto make_resource(Creator c, Destructor d, Arguments&&... args)
    {
        auto r = c(args...);
        return std::unique_ptr<decltype(*r), void(*)(decltype(r))>(r, d);
    }

Clearer?