#include #include /* const args in callbacks should be OK. */ static void _register_callback(void (*cb)(void *arg), void *arg) { } #define register_callback(cb, arg) \ _register_callback(typesafe_cb(void, (cb), (arg)), (arg)) static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg) { } #define register_callback_pre(cb, arg) \ _register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg)) static void _register_callback_post(void (*cb)(void *arg, int x), void *arg) { } #define register_callback_post(cb, arg) \ _register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg)) static void my_callback(const char *p) { } static void my_callback_pre(int x, /*const*/ char *p) { } static void my_callback_post(/*const*/ char *p, int x) { } int main(int argc, char *argv[]) { char p[] = "hello world"; register_callback(my_callback, p); register_callback_pre(my_callback_pre, p); register_callback_post(my_callback_post, p); return 0; }