1 files changed, 1 insertions, 1 deletions

diff --git a/deflate.h b/deflate.h
index 8440790..f18c616 100644
--- a/deflate.h
+++ b/deflate.h
@@ -83,7 +83,7 @@ typedef struct static_tree_desc_s  static_tree_desc;
 typedef struct tree_desc_s {
     ct_data *dyn_tree;           /* the dynamic tree */
     int     max_code;            /* largest code with non zero frequency */
-    static_tree_desc *stat_desc; /* the corresponding static tree */
+    const static_tree_desc *stat_desc;  /* the corresponding static tree */
 } FAR tree_desc;
 
 typedef ush Pos;