2009/11/16 Surya Kiran Gullapalli
Hello all, I'm trying to come up with a solution for the following problem.
I've a macro with three arguments, but if the third is not given, it should be assumed as '0'. Something on the lines of default arguments for functions.
I'm using VS2005, and g++ 4.4.x so i can use Variadic macros, but I'm unable to come up with a solution. Is there any way i can achieve this using Boost.Preprocessor ?
I tried using BOOST_PP_IF but unable to proceed further. Any Ideas ?
#define FOO_IMPL(a, b, c) /* Definition of your macro. 3 arguments. */ // Expands to FOO_IMPL(a, b, c) if called with 3 arguments. // Expands to FOO_IMPL(a, b, 0) if called with 2 arguments. // En error if called with some other number of arguments. #define FOO(...) \ BOOST_PP_IF( \ BOOST_PP_EQUAL(PP_NARG(__VA_ARGS__), 2), \ FOO_IMPL(__VA_ARGS__, 0), \ FOO_IMPL(__VA_ARGS__)) Definition of PP_NARG is here: http://groups.google.com/group/comp.std.c/browse_thread/thread/77ee8c8f92e4a... Roman Perepelitsa.