2 This example program provides a trivial server program that listens for TCP
3 connections on port 9995. When they arrive, it writes a short message to
4 each client connection, and closes each connection once it is flushed.
6 Where possible, it exits cleanly in response to a SIGINT (ctrl-c).
15 #include <netinet/in.h>
16 # ifdef _XOPEN_SOURCE_EXTENDED
17 # include <arpa/inet.h>
19 #include <sys/socket.h>
22 #include <event2/bufferevent.h>
23 #include <event2/buffer.h>
24 #include <event2/listener.h>
25 #include <event2/util.h>
26 #include <event2/event.h>
28 static const char MESSAGE[] = "Hello, World!\n";
30 static const int PORT = 9995;
32 static void listener_cb(struct evconnlistener *, evutil_socket_t,
33 struct sockaddr *, int socklen, void *);
34 static void conn_writecb(struct bufferevent *, void *);
35 static void conn_eventcb(struct bufferevent *, short, void *);
36 static void signal_cb(evutil_socket_t, short, void *);
39 main(int argc, char **argv)
41 struct event_base *base;
42 struct evconnlistener *listener;
43 struct event *signal_event;
45 struct sockaddr_in sin = {0};
48 WSAStartup(0x0201, &wsa_data);
51 base = event_base_new();
53 fprintf(stderr, "Could not initialize libevent!\n");
57 sin.sin_family = AF_INET;
58 sin.sin_port = htons(PORT);
60 listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
61 LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
62 (struct sockaddr*)&sin,
66 fprintf(stderr, "Could not create a listener!\n");
70 signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);
72 if (!signal_event || event_add(signal_event, NULL)<0) {
73 fprintf(stderr, "Could not create/add a signal event!\n");
77 event_base_dispatch(base);
79 evconnlistener_free(listener);
80 event_free(signal_event);
81 event_base_free(base);
88 listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
89 struct sockaddr *sa, int socklen, void *user_data)
91 struct event_base *base = user_data;
92 struct bufferevent *bev;
94 bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
96 fprintf(stderr, "Error constructing bufferevent!");
97 event_base_loopbreak(base);
100 bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
101 bufferevent_enable(bev, EV_WRITE);
102 bufferevent_disable(bev, EV_READ);
104 bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
108 conn_writecb(struct bufferevent *bev, void *user_data)
110 struct evbuffer *output = bufferevent_get_output(bev);
111 if (evbuffer_get_length(output) == 0) {
112 printf("flushed answer\n");
113 bufferevent_free(bev);
118 conn_eventcb(struct bufferevent *bev, short events, void *user_data)
120 if (events & BEV_EVENT_EOF) {
121 printf("Connection closed.\n");
122 } else if (events & BEV_EVENT_ERROR) {
123 printf("Got an error on the connection: %s\n",
124 strerror(errno));/*XXX win32*/
126 /* None of the other events can happen here, since we haven't enabled
128 bufferevent_free(bev);
132 signal_cb(evutil_socket_t sig, short events, void *user_data)
134 struct event_base *base = user_data;
135 struct timeval delay = { 2, 0 };
137 printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
139 event_base_loopexit(base, &delay);