+#ifdef FEATURE_CONNECTION_KEEP_ALIVE
+ if (config->feature_flags & RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE)
+ {
+ if (config->multi_threaded)
+ {
+ set_keep_alive_timeout(keep_alive_timeout);
+ }
+ else
+ {
+ /*
+ * While we could use keep-alive without multiple threads
+ * if we didn't bother with enforcing the connection timeout,
+ * that might make Tor users sad, even though they shouldn't
+ * enable the single-threaded option anyway.
+ */
+ config->feature_flags &= ~RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE;
+ log_error(LOG_LEVEL_ERROR,
+ "Config option single-threaded disables connection keep-alive.");
+ }
+ }
+#endif
+