diff --git a/main.c b/main.c
index e542f4f..f95732c 100644
--- a/main.c
+++ b/main.c
@@ -27,8 +27,9 @@
 
 #define VERSION "15"
 
-ASSERT_SIZE(struct in_addr, 4)
-ASSERT_SIZE(struct in6_addr, 16)
+ASSERT(sizeof(struct in_addr) == 4)
+ASSERT(sizeof(struct in6_addr) == 16)
+
 
 char ip_option[1] = "\0";
 
diff --git a/params.h b/params.h
index 5d3d7dd..706be71 100644
--- a/params.h
+++ b/params.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdbool.h>
+#include <assert.h>
 
 #include "mpool.h"
 
@@ -131,7 +132,6 @@ extern struct packet fake_udp;
 
 extern char ip_option[1];
 
-#define ASSERT_SIZE(stc, len) \
-    static char t[-(int)sizeof(stc) + len]; \
-    static char tt[(int)sizeof(t) * -1];
+#define ASSERT(exp) \
+    char t[(exp) ? 1 : -1];
 #endif