1 files changed, 2 insertions, 2 deletions

diff --git a/src/syntax.c b/src/syntax.c
index 4ab87a3a3c2..b17a8d4d0bc 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -877,8 +877,8 @@ DEFUN ("modify-syntax-entry", Fmodify_syntax_entry, Smodify_syntax_entry, 2, 3,
   if (*p)
     {
       int len;
-      int character = STRING_CHAR_AND_LENGTH (p, XSTRING (newentry)->size - 1,
-                                              len);
+      int character = (STRING_CHAR_AND_LENGTH
+                       (p, STRING_BYTES (XSTRING (newentry)) - 1, len));
       XSETINT (match, character);
       if (XFASTINT (match) == ' ')
         match = Qnil;