diff --git a/src/mbyte.c b/src/mbyte.c
index 406d109..07446ca 100644
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -5542,6 +5542,20 @@
     return retval;
 }
 
+/*
+ * Return 1 or 2 when "c" is in the cellwidth table.
+ * Return 0 if not.
+ */
+    int
+get_cellwidth(int c UNUSED)
+{
+#ifdef FEAT_EVAL
+    return cw_value(c);
+#else
+    return 0;
+#endif
+}
+
 #if defined(FEAT_EVAL) || defined(PROTO)
 
 /*