diff --git a/main.c b/main.c
index 04f6a30..bd443cf 100644
--- a/main.c
+++ b/main.c
@@ -4,18 +4,34 @@
 #include "ltrace.h"
 
 /*
+static int count_call =0;
+static int count_ret  =0;
+
 static void
-callback(Event * ev) {
-	printf("\n\tcallback(ev->type=%d)\n", ev->type);
+callback_call(Event * ev) {
+	count_call ++;
+}
+static void
+callback_ret(Event * ev) {
+	count_ret ++;
+}
+
+static void
+endcallback(Event *ev) {
+	printf("%d calls\n%d rets\n",count_call, count_ret);
 }
 */
 
 int
 main(int argc, char *argv[]) {
 	ltrace_init(argc, argv);
+
 /*
-	ltrace_add_callback(callback);
+	ltrace_add_callback(callback_call, EVENT_SYSCALL);
+	ltrace_add_callback(callback_ret, EVENT_SYSRET);
+	ltrace_add_callback(endcallback, EVENT_EXIT);
 */
+
 	ltrace_main();
 	return 0;
 }