[Boost-users] quick question about macro

hi there! I'm using boost library occasionally and have this simpleton question to ask. i need to debug *boost::asio::io_service* by enabling *BOOST_ASIO_ENABLE_HANDLER_TRACKING* macro. so, do I have to rebuild the library like * ./b2 cxxflags="-DBOOST_ASIO_ENABLE_HANDLER_TRACKING"...* or adding * #define BOOST_ASIO_ENABLE_HANDLER_TRACKING* to my source file is enough? (this doesn't work for me, so i suspect I should go with the first option) thanks, -- Peter Gusev