fmt_write = bt_lookup_format(g_quark_from_static_string(opt_output_format));
if (!fmt_write) {
fprintf(stdout, "[error] format \"%s\" is not supported.\n\n",
fmt_write = bt_lookup_format(g_quark_from_static_string(opt_output_format));
if (!fmt_write) {
fprintf(stdout, "[error] format \"%s\" is not supported.\n\n",