+ boost::system::error_code ec;
+ copy_file(path_to_copy, add_number(path_to_copy, n), ec);
+ };
+
+ /* Make a backup copy of any config.xml, cinemas.xml, dkdm_recipients.xml that we might be about
+ * to write over. This is more intended for the situation where we have a corrupted config.xml,
+ * and decide to overwrite it with a new one (possibly losing important details in the corrupted
+ * file). But we might as well back up the other files while we're about it.
+ */
+
+ /* This uses the State::write_path stuff so, e.g. for a current version 2.16 we might copy
+ * ~/.config/dcpomatic2/2.16/config.xml to ~/.config/dcpomatic2/2.16/config.xml.1
+ */
+ copy_adding_number (config_write_file());