base class for KennyKerr::unique_handle (https://dx.codeplex.com)

handle_traits_base.hpp

template<class T, T invalid_value=nullptr>
struct handle_traits_base
{
	using pointer = T;
	inline static pointer invalid() throw()
	{
		return invalid_value;
	}
};

//sample use
struct hdesk_traits : handle_traits_base<HDESK>
{
	static void close(pointer ptr) throw()
	{
		CloseDesktop(ptr);
	}
};

using unique_hdesk = KennyKerr::unique_handle<hdesk_traits>;