Hello, Thank you for the parameter library; it is making my library much nicer to use. Two questions: 1. I am assuming there is no runtime penalty to use the BOOST_PARAMETER version of a function. Is that right? 2. My code looks like that: namespace keywords { BOOST_PARAMETER_NAME(id) BOOST_PARAMETER_NAME(test) } BOOST_PARAMETER_FUNCTION ( (void),foo,keywords::tag, (optional (id, *, "") (test, (const char*), "") ) ) { ... } Here the parameters must be converted, if necessary, to const char* in order to be used later. What would be the best way to write the requirement that the type must be const char* or must be convertible to const char*? thanks for your help