suppress warning in x64
diff --git a/skeletons/converter-sample.c b/skeletons/converter-sample.c
index 178264e..4119263 100644
--- a/skeletons/converter-sample.c
+++ b/skeletons/converter-sample.c
@@ -106,7 +106,7 @@
 }
 
 
-#define OP_OFFSET(fname)  (unsigned)(&(((asn_TYPE_operation_t *)0)->fname))
+#define OP_OFFSET(fname)  (size_t)(&(((asn_TYPE_operation_t *)0)->fname))
 typedef struct {
     const char *name;
     enum asn_transfer_syntax syntax;