diff --git a/src/core/init.c b/src/core/init.c
index 31314613..ea3b5ebe 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -337,7 +337,7 @@ void
 lwip_init(void)
 {
 #ifndef LWIP_SKIP_CONST_CHECK
-  int a;
+  int a = 0;
   LWIP_UNUSED_ARG(a);
   LWIP_ASSERT("LWIP_CONST_CAST not implemented correctly. Check your lwIP port.", LWIP_CONST_CAST(void*, &a) == &a);
 #endif