+ pthread_t worker_thread;
+
+ // Mutex protecting queued_data only. Note that if you want to hold both this
+ // and <mutex> below, you will need to take <mutex> before this one.
+ mutable pthread_mutex_t queued_data_mutex;
+
+ // Deferred commands that should be run from the do_work() thread as soon as possible.
+ // We defer these for two reasons:
+ //
+ // - We only want to fiddle with epoll from one thread at any given time,
+ // and doing add_client() from the acceptor thread would violate that.
+ // - We don't want the input thread(s) hanging on <mutex> when doing
+ // add_data(), since they want to do add_data() rather often, and <mutex>
+ // can be taken a lot of the time.
+ //
+ // Protected by <queued_data_mutex>.
+ std::vector<int> queued_add_clients;
+ std::map<std::string, std::string> queued_data;
+
+ // All variables below this line are protected by the mutex.
+ mutable pthread_mutex_t mutex;
+
+ // If the thread should stop or not.
+ bool should_stop;