diff --git a/resource.c b/resource.c
index 23484ab1..acfe488e 100644
--- a/resource.c
+++ b/resource.c
@@ -409,7 +409,7 @@ coap_delete_attr(coap_attr_t *attr) {
     coap_free(attr->name.s);
   if (attr->flags & COAP_ATTR_FLAGS_RELEASE_VALUE)
     coap_free(attr->value.s);
-#ifdef POSIX
+#ifdef WITH_POSIX
   coap_free(attr);
 #endif
 #ifdef WITH_LWIP