diff --git a/thunk.c b/thunk.c
index 17f3d320bb..7f31cffe09 100644
--- a/thunk.c
+++ b/thunk.c
@@ -86,7 +86,7 @@ void thunk_register_struct(int id, const char *name, const argtype *types)
 #endif
     /* now we can alloc the data */
 
-    for(i = 0;i < 2; i++) {
+    for (i = 0; i < ARRAY_SIZE(se->field_offsets); i++) {
         offset = 0;
         max_align = 1;
         se->field_offsets[i] = g_new(int, nb_fields);