diff --git a/src/optionstr.c b/src/optionstr.c
index d7cb38a..08b2350 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -3040,6 +3040,30 @@
     return NULL;
 }
 
+/*
+ * Process the updated 'messagesopt' option value.
+ */
+    char *
+did_set_messagesopt(optset_T *args UNUSED)
+{
+    if (messagesopt_changed() == FAIL)
+	return e_invalid_argument;
+
+    return NULL;
+}
+
+    int
+expand_set_messagesopt(optexpand_T *args, int *numMatches, char_u ***matches)
+{
+    static char *(p_meo_values[]) = {"hit-enter", "wait:", "history:", NULL};
+    return expand_set_opt_string(
+	    args,
+	    p_meo_values,
+	    ARRAY_LENGTH(p_meo_values) - 1,
+	    numMatches,
+	    matches);
+}
+
 #if defined(FEAT_SPELL) || defined(PROTO)
 /*
  * The 'mkspellmem' option is changed.