+/* Lookup the default database path.
+ *
+ * This is the path that will be used by notmuch_database_create and
+ * notmuch_database_open if given a NULL path. Specifically it will be
+ * the value of the NOTMUCH_BASE environment variable if set,
+ * otherwise ${HOME}/mail
+ *
+ * Returns a newly allocated string which the caller should free()
+ * when finished with it.
+ */
+char *
+notmuch_database_default_path (void);
+