1 files changed, 2 insertions, 1 deletions

diff --git a/src/fns.c b/src/fns.c
index 4dd04bf0b50..06d04781789 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -2370,8 +2370,9 @@ This makes STRING unibyte and may change its length.  */)
      (string)
      Lisp_Object string;
 {
-  int len = SBYTES (string);
+  int len;
   CHECK_STRING (string);
+  len = SBYTES (string);
   bzero (SDATA (string), len);
   STRING_SET_CHARS (string, len);
   STRING_SET_UNIBYTE (string);