Michael Marcin wrote:
The documentation makes no mention of allowing extension for user defined types. It in fact has a table which clearly states that param_type is a const reference for all user defined types.
In a specific case I was working on a 3d renderer that we used for a mobile project where we used a templated fixed point class. There were some low level functions that worked on a typename Real which used pass by const reference because cheap copy was not a requirement of our Real concept. This project happened to only be using this fixed point type which was a wrapper over int. We branched the code and changed the functions to pass by value. This resulted in a measurable performance increase.
I would like to take classes like this and specialized param_type for them but the documentation for this library doesn't seem to allow for that.
There's nothing to stop you from adding a full or partial specialisation of call_traits to your header: struct my_value_type{ ... }; namespace boost{ template<> struct call_traits<my_value_type> { typedef my_value_type value_type; typedef my_value_type& reference; typedef my_value_type const& const_reference; typedef my_value_type param_type; }; } // namespace Then once your functions are call_traits aware, it's then easy to tweek behaviour by adding specialisations as required. Does this help? John.