+ string const s = doc.write_to_string_formatted ();
+ boost::filesystem::path tmp (string(config_file().string()).append(".tmp"));
+ FILE* f = fopen_boost (tmp, "w");
+ if (!f) {
+ throw FileError (_("Could not open file for writing"), tmp);
+ }
+ checked_fwrite (s.c_str(), s.length(), f, tmp);
+ fclose (f);
+ boost::filesystem::remove (config_file());
+ boost::filesystem::rename (tmp, config_file());