--- /dev/null
+#include "typesafe_cb/typesafe_cb.h"
+#include <stdlib.h>
+
+void _callback(void (*fn)(void *arg), void *arg);
+void _callback(void (*fn)(void *arg), void *arg)
+{
+ fn(arg);
+}
+
+/* Callback is set up to warn if arg isn't a pointer (since it won't
+ * pass cleanly to _callback's second arg. */
+#define callback(fn, arg) \
+ _callback(typesafe_cb(void, (fn), (arg)), (arg))
+
+void my_callback(int something);
+void my_callback(int something)
+{
+}
+
+int main(int argc, char *argv[])
+{
+#ifdef FAIL
+ /* This fails due to arg, not due to cast. */
+ callback(my_callback, 100);
+#endif
+ return 0;
+}