update_ref(): improve documentation

diff --git a/notes.c b/notes.c
index c763a21eef5b64c984c22d18cd5f21c1bd32e5a3..2be4d7f3fd081476001212b103f011e45b4a9c41 100644 (file)
--- a/notes.c
+++ b/notes.c
@@ -1006,7 +1006,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
        t->root = (struct int_node *) xcalloc(1, sizeof(struct int_node));
        t->first_non_note = NULL;
        t->prev_non_note = NULL;
-       t->ref = notes_ref ? xstrdup(notes_ref) : NULL;
+       t->ref = xstrdup_or_null(notes_ref);
        t->combine_notes = combine_notes;
        t->initialized = 1;
        t->dirty = 0;