diff --git a/sds.h b/sds.h
index 394f8b5..13be75a 100644
--- a/sds.h
+++ b/sds.h
@@ -79,7 +79,7 @@ struct __attribute__ ((__packed__)) sdshdr64 {
 #define SDS_TYPE_64 4
 #define SDS_TYPE_MASK 7
 #define SDS_TYPE_BITS 3
-#define SDS_HDR_VAR(T,s) struct sdshdr##T *sh = (void*)((s)-(sizeof(struct sdshdr##T)));
+#define SDS_HDR_VAR(T,s) struct sdshdr##T *sh = (struct sdshdr##T *)((s)-(sizeof(struct sdshdr##T)));
 #define SDS_HDR(T,s) ((struct sdshdr##T *)((s)-(sizeof(struct sdshdr##T))))
 #define SDS_TYPE_5_LEN(f) ((f)>>SDS_TYPE_BITS)