#define BOOST_SIGNALS_ARGS_AS_MEMBERS T1 a1;
#define BOOST_SIGNALS_COPY_PARMS T1 ia1
#define BOOST_SIGNALS_INIT_ARGS :a1(ia1)
-#define BOOST_SIGNALS_ARG_TYPES typedef T1 arg2_type;
+#define BOOST_SIGNALS_ARG_TYPES typedef T1 arg1_type;
#include <boost/signals/signal_template.hpp>